Groups in the 2000-range:

The groups F17C 2201/00 - F17C 2209/00 cover features of the pressure vessel itself:

The groups F17C 2221/00 - F17C 2227/00 consider the fluid contained in the pressure vessel and its charging and discharging into and from the pressure vessel.

Layout of definition statements:

"Positive" examples have been chosen among patents to illustrate the definition statement and what is to be classified in the groups of the 2000 range. The qualifying features are marked in green in these drawings.

To illustrate the boundaries of the definition statement, "negative" examples have been chosen among patents to illustrate what would not lead to or even disqualify from a classification in a group. The corresponding features are marked in red in these drawings.

The fluid contained in the vessel according to F17C should be a gas. It is stored in a gaseous, mostly compressed, or in a liquefied or solidified state of matter in the pressure vessel.

Vessels that contain other substances than gases are classified in B65D.

Gas that is stored in solved or adsorbed form are classified in F17C 11/00.

Liquefaction, solidification or separation of gases or gaseous mixtures by pressure and cold treatment are classified in F25J.

Vessels in which processes take place, like chemical reactions, nuclear reactions, gas mixing or liquefaction, are classified in corresponding subclasses, like B01F 23/00 for mixing, e.g. dispersing, emulsifying, according to the phases to be mixed.

Processes involving gas, but for which the focus is on the process external to the pressure vessel and not on the pressure vessel itself, should be classified in subclasses relevant to the process.

Pressure vessel containing additionally to the gas another product or apparatus for which the gas serves as a carrier or a means for achieving another effect than storage, are to be classified in subclasses relevant to the application.

Documents classified in F17C should also get classifications in the 2000 series of this subclass. Classification in those Indexing Codes is mandatory.

Each technical feature in line with a definition should get this classification. There is theoretically no limitation to the quantity of symbols that can be attributed to one single document.

A document contains a technical feature when either this feature is explicitly mentioned in the text or undoubtedly visible in the drawings (e.g.: a weld seam symbol in a drawing has to be classified). Features that are implicit but not mentioned should generally not be considered. Exceptionally, when a feature is not explicitly mentioned but there is no doubt that this particular feature is meant, it may be classified too.

All embodiments have to be considered individually and their features separately identified and classified.

In the exceptional case that one feature reasonably fits into more than one definition, it can be classified in all of them.

Documents should, be classified within this 2000 series completely or not at all, to identify easily if complete classification of all features have been given. Simply attributing e.g. a single classification in that range to a document and not classifying all the other technical features should be avoided.

If the text contains a term which is very specific in the art of "pressure vessels for gas storage and transport" (e.g. "liner" or "LNG"), but its definition or use in the document seems to be in contradiction with the definition herein or the general knowledge of person skilled in the art, the term should in any case be considered and a classification code related to the term should be attributed.

When prior art (e.g. in form of patent numbers, summaries or drawings about prior art) is specifically mentioned in the document, its technical features are NOT considered for classification.

Warning about reorganisation!

Only a part of the documents classified in main groups F17C 1/00 - F17C 9/00 and F17C 13/00 have been coded completely in the 2000 series.

Consequently, in future all documents of subclass F17C should be classified in the 2000 series of F17C. No documents from subclass F17B have been classified so far in this scheme.

Constructional aspects of vessel for containing gas under high pressure.

Constructional aspects of vessel for containing liquefied gas or cryogenic fluid which is not under high pressure such as details about the insulation or about the suspension of an inner vessel within an outer vessel.

The filling of a receiver vessel with a gas at a high pressure.

The filling a vessel with a low pressure as for liquefied gas or cryogenic fluid.

The discharging of a vessel comprising a gas stored with a high pressure therein.

The discharging of a vessel comprising a gas stored with a low pressure therein as for liquefied gas or cryogenic fluid.

Means for coding or identifying vessels or their content, special adaptations of indicating, measuring, monitoring and regulating, mounting arrangements of vessels, it means their integration in their area of use, arrangement or mounting devices for preventing or minimising the effect of explosion, arrangement of valves, and closures.

Pressure vessels for which either the shape or axis orientation can be determined or the size either determined or estimated.

Pressure vessels the shape of which can be identified. For grouped vessel, the shape of the single vessel has to be considered individually, not the shape of the group per se.

In this positive example from GB818073: the shape of the vessel is the shape of the inner vessel.

In this negative example from GB818073, the outer jacket shape is NOT to be considered, as the definition of "shape" excludes the contour of external frames, covers, boxes etc...

In this negative example from US20080178611, the shape is not classified, as in this purely functional drawings, the vessels is represented symbolically. Symbolic information is generally not considered sufficient to determine a shape, unless the drawing is explicit and realistic, which is not the case here.

In most cases, the exterior shape of a vessel is identical to the interior shape of the vessel. It may though happen that a pressure vessel discloses a visible exterior shape that is different from the interior contour. In these exceptional cases, the classification codes of both shapes have to be allocated.

Pressure vessels with an axis and a cylindrical form with circular sections

Cylindrical pressure vessels with at least one exteriorly curved end-piece. The form of the end-piece is convex when considered from the outside and this convex form has to be dominant.

In this positive example from DE8619754U, the shape is a half-globe.

In this positive example from WO2053966, the shape has a flat bottom, but is dominantly exteriorly curved.

In this negative example from DE19952611, the round corners seem related to the manufacturing of the vessel. The flat bottom is dominant: the vessel is classified as having flat end-pieces.

Cylindrical pressure vessels with at least one interiorly curved end-piece. The form of the end-piece is concave when considered from the outside and this concave form has to be dominant.

In this positive example from DE877461, the shape of the vessel is interiorly curved.

Cylindrical pressure vessels with at least one flat end-piece. The flat form has to be dominant.

In this positive example from CH1480971, the shape of the vessel is flat.

In this negative example from DE490791, the curved portion is dominant upon the flat one: the vessel is classified as having exteriorly curved end-pieces.

Cylindrical pressure vessels for which in the middle part, the cross section has not a constant surface along the axis.

Cylindrical pressure vessels for which the wall thickness in the middle part is not constant along the axis.

The variations in thickness or diameter can be the result of a variable wall thickness along the axis, but also the result of e.g. rings added externally on the middle part.

In this positive example from US2280501, the thickness of the wall is not constant.

In this positive example from BE405843, the thickness of the wall is constant, but not the surface of the section.

In this negative example from DE10325598, the wall of the end piece, but not of the middle part, has a variable thickness.

Pressure vessels with a spherical or elliptical shape.

In this positive example from DE3131040, the shape is elliptical .

In this positive example from WO9612914, the shape is spherical.

In this negative example from DE800230, the shape seems elliptical but from the text indicated that the vessel is cylindrical (cross sections may be misleading).

Pressure vessels with toroidal form, like a hoop or a tire, that actually often replace spare tires in cars.

In this positive example from DE3316539, the shape is a tore.

Pressure vessels in form of a tube or a hose. The diameter of the tube is small in comparison with the extended length of the tube.

In this positive example from DE2305840 , the shape is tubular, even if the entire construction may look like a cylinder.

In this positive example from DE19547752, the shape is tubular.

In this negative example from US2008256960, the middle part is tubular, but the vessel is actually cylindrical.

Pressure vessels in a general conical form, i.e. cylindrical with an increasing and/or decreasing cross section.

In this positive example from WO2004005790, the shape is conical.

In this positive example from DE19747907 the shape is conical.

In this negative example from GB521979, the vessel is cylindrical, with an intermediate conical connection to the end-piece.

Pressure vessels the shape of which is not covered by the groups above, i.e. not cylindrical, spherical, elliptical, tubular or conical.

Pressure vessels the shape of which is not an association of fluidly connected shapes covered by the groups above, not cylindrical, spherical, elliptical, tubular or conical.

In this positive example from DE2931947, the shape is simple, but compliant with the definition of complex.

In this negative example from WO0049330, two cylindrical pressure vessel are bundled. This vessel "cylindrical with exteriorly curved end pieces" (F17C 2201/0109) and the bundle is considered as "two or more vessels " (F17C 2205/013).

Pressure vessels with the shape of connected curved wall segments.

In this positive example from DE1944315, the external shape consists of lobes, with an single internal volume.

In this positive example from EP1355105, the external shape consists of lobes, with several distinct internal volumes.

Pressure vessels with the shape of connected flat wall segments with generally sharp edges.

In this positive example from FR2781555, the external shape is polygonal, with several distinct internal volumes.

In this negative example from CH148097, the shape seems polygonal, but the pressure vessel is actually cylindrical (cross sections may be misleading).

Pressure vessels with a honeycomb structure (6 edges) inside the vessel, in contact with the stored fluid.

In this positive example from FR1268538, the honeycomb structure is in contact with the fluid.

In this negative example from NL7414082, the honeycomb structure is located in the insulation layer and is thus not in contact with the stored fluid.

Pressure vessels with the inner storage volume subdivided in individual volumes. These volumes are separated by common walls.

In this positive example from FR2781555 , 10 chambers are visible.

In this positive example from GB412814, 2 chambers are visible.

In this negative example from DE1946465, several distinct cylindrical vessels are fluidly connected and arranged in a bundle (F17C 2205/0134).

In this negative example from US1692670, two clearly distinguishable cylindrical vessels are mounted one inside the other (F17C 2205/0149).

Pressure vessel forming a single vessel wherein pressure balance between several distinct chambers is obtained via a permanent open hole between these chambers. For "pressure vessels divided in several chambers", the permanent open hole is situated in the common wall.

In this positive example from DE63206430, the 3 chambers of the " pressure vessel divided in several chambers" are connected by two permanent holes.

In this positive example from FR783241, a single vessel, materialized by its common external hull and its common fittings, is created by connecting cylindrical chambers via a permanent connection. This connection can be assimilated to holes as the cylindrical chambers are close to each other.

In this negative example from GB693156, two strictly separated vessels are simply connected by a pipe. No common vessel is created and the pipe is too long to be considered a hole.

In this negative example from DE531720, a hole connects two chambers of the vessel, but an inserted valve allows no pressure balance.

Pressure vessel with a non-constant or variable shape or with a non-constant or variable inner or outer volume.

In this positive example from DE102009017650, the shape is constant, but the volume changes.

Warning about pending reorganisation: Documents from F17B that will be deep-indexed with be classified herein.

Pressure vessel with an inflatable bag located in the vessel to retain the fluid.

In this positive example from US6234352, the bladder is attached on top.

When counting the number of layers in the group F17C 2203/0612, a bladder is not counted.

Pressure vessel with volume separating membrane attached to the inner wall of the vessel along a line.

In this positive example from GB80450, a membrane separates the vessel in two.

In this negative example from DE29816811U, a bladder separates the vessel in two.

Bladders have the function of a separating membrane, but are only classified in F17C 2201/018.

Pressure vessel with a volume separating piston.

In this positive example from US5253682, a free piston in the vessel helps discharging.

In this negative example from US3426545, the piston is part of a pump.

Pressure vessel in form of a bellows.

In this positive example from US3270905, the whole pressure vessel is a bellows.

Pressure vessels for which an axis can be defined and for which this axis has a defined orientation when mounted or in use. The orientation is mostly suggested by a device that allows or constrains the pressure vessel to be oriented a certain way. Such devices can be supporting feet, hanging up devices, frames etc.

In this positive example from GB494426, the pressure vessel has a vertical orientation due to its flat bottom acting as a mounting foot.

In this negative example from DE19934851, the vessel is a cylindrical bottle that can be turned upside down or oriented in any direction, without any preferred direction.

In this negative example from US3468264, no main axis of the vessel on the ship is identifiable.

Pressure vessels for which the axis has a vertical orientation.

In this positive example from DE199106, the pressure vessel is cylindrical and has a flat bottom.

Pressure vessels with toroidal shape are classified herein, their axis passing through the middle of the hole.

Pressure vessels for which the axis has a horizontal orientation

In this positive example from DE10022741, the cylindrical vessel rests on mounting feet.

Pressure vessels for which the axis is neither horizontal nor vertical.

In this positive example from EP2312196, the pressure vessel is mounted on an inclined frame.

Pressure vessels for which the inner storage volume can be determined.

Pressure vessels for which the inner storage volume can be estimated. The volume can be suggested by any hint, like objects in the drawings or knowledge from the context the pressure vessel is used in.

In this positive example from US20040003743, the size of the human allows to estimate the size of the vessel.

In this negative example from BE427219, the pressure vessel "looks" small, but there is no hint about the size.

In this negative example from NL7314739, the storage capacity of the whole ship is certainly large, but not to be considered as the vessels are probably bundled, and the size of the individual vessel is difficult to estimate.

In case of bundled pressures vessels from F17C 2205/0134, the volume of the individual pressure vessel has to be classified, not the resulting overall volume.

The rule of classification, according to which a technical feature has to be explicitly mentioned, is not strictly applicable here: the size is a technical feature that can be estimated.

The boundaries indicated in the groups (30 liters, 1 m³, 1000 m³) are merely to be understood as an indication and an order of magnitude. They are not binding or strict.

In doubt, it is recommended to classify into two adjacent classes (portable and small, or small and medium, or medium and large) simultaneously.

Pressure vessels of large size, an order of magnitude being 1000 m³. Such pressure vessels often appear in terminals, on subterranean caverns, on maritime gas carriers or sewage plants and hints that suggest a large size are often houses or ships.

In this positive example from WO9962794, the large size of the vessel is suggested by the building.

Pressure vessels of medium size (between 1 m³ and 1000 m³), often appearing e.g. on trailers supplying fuel stations, in installations for gas supply or in domestic use, e.g. buried LPG tanks.

In this positive example from DE10027619, the vessel is mounted on a trailer.

Pressure vessels of small size (between 0,03 m³ and 1 m³), often appearing on cars, in domestic use or with transporting means on wheels.

In this positive example from US2005183425, the pressure vessel stores gas fuel in a car.

Pressure vessels of small size (up to 30 liters), like gas bottles or cartridges, which are typically portable or liftable by a single human by muscular force.

In this positive example from NL7708523, the pressure vessel is a gas cartridge.

Pressure vessels containing floating elements in the liquid, which have only a physical and no chemical interaction with the fluid. Such elements are for instance microspheres or open spheres that prevent slosh.

In this positive example from US2008272130, spheres fill the whole container.

In this negative example from WO0211860, the pressure vessel is filled with an adsorbing medium, allowing adsorption and desorption of the fluid (F17C 11/00)

Pressure vessels for which technical features of the vessel wall and its structure can be determined.

Overlapping filament wraps are considered as one layer, as long as they form a functional envelope. They are often manufactured in one single process step.

The following items are not counted as wall or layer (convention for counting walls and layers): a thermal insulation envelope, a bladder, a coating.

Pressure vessels for which means, additionally to the wall, are provided, to strengthen the wall.

Pressure vessels in which the means to strengthen the wall are integrated in the wall or placed on the wall, e.g. in form of ribs or bars.

In this positive example from GB476713, circumferential reinforcing rings are mounted on the middle part.

In this positive example from FR2799526, a reinforcing bar is mounted in the inner separation wall, in particular in a column inside the vessel.

In this negative example from US5822838, the wall is made of wound filament. This filament is no additional means to reinforce the wall, but defines the wall itself.

Pressure vessels in which the means to strengthen the wall are wall-to-wall bars, columns or rods in the interior of the pressure vessel.

In this positive example from EP0166492, wall-to-wall columns connect and support the two upper and lower flat walls.

In this negative example from DE4300484, the reinforcing means on the inner wall do not have a wall-to-wall column structure.

Pressure vessels with an inner and a separate outer vessel wall, the inner vessel wall being held in the outer vessel wall by suspensions means, which are mostly designed to minimize thermal transfer.

In this negative example from DE101347733, the whole vessel is mounted in a frame.

In this negative example from WO2010020431, circumferential bearing means (F17C 2205/0192) are no suspension means, as they hold the entire vessel upright from the outside.

.

Bearing means for the vessel itself are classified in F17C 2205/0192.

Pressure vessels in which the suspension means are in form of stiff bars, that can be submitted to traction or compression.

In this positive example from WO9859195, bars hold the inner tank.

Pressure vessels in which the suspension means are in form of cords, submitted to traction only.

In this positive example from DE603062, the inner vessel is held by a cord.

In this negative example from US6345933, cords attach the entire vessel to the ground (F17C 2205/0184).

Pressure vessels in which the suspension means are in form of magnetic means, avoiding contact between the vessel walls.

In this positive example from WO2006034521, the inner vessel is held in place by magnets.

Pressure vessels in which the inner vessel is attached at its neck to the outer vessel.

In this positive example from US4218892, the inner vessel of the vertical pressure vessel is attached at the neck only.

In this negative example from EP1041337, a bladder is attached at the neck.

Bladders F17C 2201/018 are usually attached at the neck, but they are not to be classified here.

Pressure vessels in which insulating means are provided to avoid or reduce thermal transfer between the fluid in the pressure vessel and the environment.

When counting the number of layers in the group F17C 2203/0612, the thermal insulation layer is not counted.

Any material surrounding a pressure vessel has some thermal insulating effect, but only those documents should be considered having a thermal insulation in which the function of thermal insulation is explicitly mentioned.

Pressure vessels in which the insulating means have a solid consistency.

Pressure vessels in which the insulating means prevent radiation thermal transfer, like e.g. aluminum coating.

In this positive example from GB2454475, a radiation shield is wrapped around the vessel.

Pressure vessels in which the radiation shield is cooled and the heat is transferred by external means.

In this positive example from GB2414539, a cooling medium in form of a fluid is circulated and in contact with the shield.

Pressure vessels containing gas in a liquefied phase and in which the radiation shield is cooled by the gas in vaporized form. Usually, the gas has a cooling effect because of its discharge.

In this positive example from GB2025029, a constant flow of very cold vaporised helium serves as coolant for the shield.

Pressure vessels comprising a layer made of several thin reflective foils, sometimes in form of pads.

In this positive example from US6521077, multi-sheet blankets form insulation pads.

In this negative example from US3133659 a thicker ribbon is wrapped around the vessel in an overlapping helical scheme.

In this negative example from US3092148, a thicker sheet is wrapped several times around the vessel.

Pressure vessels in which the insulating means is made of aerogel, a material comprising about 99% pores.

In this positive example from US2010146992, granular aerogel surrounds the inner vessel.

Pressure vessels in which the insulating means is made of foam

In this positive example from EP0166492, foam is integrated in the wall.

Pressure vessel in which the foam is made of polyurethane.

Pressure vessels in which the insulating means is in granular form.

In this positive example from AU439960, ceramic balls are integrated in the wall.

Pressure vessels in which the insulating means is perlite in granular form.

In this positive example from WO2006001711, perlite is integrated in the wall.

Pressure vessels in which the insulating means is in fiber form.

In this positive example from US2004256395, fibers fulfill the explicit task of thermal insulation.

In this negative example from DE3103646, insulation is not mentioned in relation with the fibers.

Pressure vessels in which the fibers are glass wool.

In this positive example from US4366917, two glass wool fiber layers are used.

In this positive example from US3583351, a single glass wool fibre layer is used.

Pressure vessels in which the insulating means is wood.

In this positive example from DE2349100, wooden heat insulation is used on a ship.

Pressure vessels in which the insulating means is in form of panels, usually placed next to each other.

In this positive example from EP0543686, insulation on a ship is in form of panels.

Pressure vessels in which the insulating means is in liquid form.

In this positive example from US2507778, a liquid serves as insulating means.

Pressure vessels in which the liquid insulating means is a cryogen.

In this positive example from WO2007026332, liquefied cryogenic gas at its boiling point is used for insulation

Pressure vessels in which the liquid insulating means is water.

In this positive example from US2009114290, water is the insulating means.

Pressure vessels in which the insulating means is gaseous.

In this positive example from WO2009147162, an insulating cavity is filled with gas.

Pressure vessels in which the gaseous insulating means is an inert, non-reactive gas.

In this positive example from US3319431, an insulating cavity is filled with a non-combustible gas.

Pressure vessels in which the gaseous insulating means is air.

In this positive example from GB832880, air surrounds the vessel.

Pressure vessels in which the gaseous insulating means is a cryogen.

Pressure vessels in which the insulation is reached by evacuating an insulating cavity.

In this positive example from WO03018344, a vacuum cavity surrounds the vessel.

Pressure vessels in which the vacuum is maintained at a desired level by a getter, a reactive material used to remove traces of gas. The getter can be in form of a specific coating applied to the surface within the evacuated chamber.

In this positive example from WO9325843, the getter is placed in the intermediate evacuated space.

Pressure vessels for which the wall composition and layer structure and properties of these layers can be determined.

Pressure vessels comprising a liner, a solid layer located on the inner side of the vessel that prevents diffusion of the fluid and thus contact of the fluid with other layers and eventually corrosion. Liners are usually thin, and only moderately contribute to the mechanical resistance of the vessel.

In this positive example of EP0343098, a liner made of stainless steel is mounted in a pressure vessel for high-purity fluid. The term "liner" does not appear in the text.

In this negative example from EP2166260 coating for corrosion protection is sprayed on the vessel surface.

A liner is counted as a layer.

A layer fulfilling all the requirements of a liner (solid layer on the inner side to prevent diffusion) is to be classified herein too, even if the word "liner" does not explicitly appear.

If the word "liner" appears in the document, but the functionality of this "liner" differs from the requirements of a liner (solid layer on the inner side to prevent diffusion), the document is to be classified herein too.

If the word "liner" appears in the document without any further explanation, the document is to be classified herein too.

Simple coatings for corrosion protection are not to be considered as a liner.

Pressure vessels comprising a coating, a very thin painted or sprayed protection, usually against corrosion.

In this positive example from US2004089440, a coating is sprayed on the outside.

A coating is not is counted as a layer.

A layer fulfilling all the requirements of a coating (very thin, painted or sprayed) is to be classified here too, even if the word "coating" does not explicitly appear.

If the word "coating" appears in the document, like for cement coating, but the functionality of this "coating" differs from the requirements of a coating (very thin, painted or sprayed), the document is to be classified here too,

If the word "coating" appears in the document without any further explanation, the document is to be classified here too.

Pressure vessels comprising a layer made of usually adjacently wrapped bands, straps or ribbons.

In this positive example from NL6413265, ribbons are wrapped around a cylindrical vessel.

In this negative example from GB1518156, filaments, which have no ribbon form, are wrapped around a vessel.

Straps, bands or ribbons are counted as a layer.

Pressure vessels for which the number of walls and/or layers can be counted.

In this positive example from WO02074616, the drawing indicates 4 layers (layers 1-4), but from the definition of "layer", these 4 filament wraps are counted as one single layer.

In this positive example from GB1150131, the vessel comprises an inner envelope, and an outer envelope for thermal insulation. The inner envelope counts for a single wall (with one layer). Thermal insulation is per convention not counted as wall or layer.

Pressure vessels comprising only one wall made of one or several layers.

In this negative example from GB2440350, thermal insulation cavities separate and thus create 3 walls.

Pressure vessels, for which the single wall comprises only one layer.

In this positive example from NL7906614, the metallic vessel has the simplest construction with one single layered wall.

Pressure vessels, for which the single wall comprises two layers.

In this positive example from DE3716426, two layers are visible.

Pressure vessels, for which the single wall comprises three layers.

In this positive example from US3140006, three layers are visible.

Pressure vessels, for which the single wall comprises four or more layers.

In this positive example from US3372828, the single wall is made of 9 layers.

Pressure vessels comprising two or more walls. Usually, thermal insulating envelopes or cavities filled with a different fluid than the fluid stored, generate walls.

In this negative example from GB2249377, the stored fluid fills the cavities between of the pressure vessel: only one wall is counted.

For pressure vessels with two or more walls, no layers are counted.

Pressure vessels comprising two walls

In general the two structural walls are separated by thermal insulation.

In this positive example from WO0031459, two separated packages of layers defining two walls are separated by a space.

This negative example from DE3716426, one single wall with two layers is visible, without any separating space.

Pressure vessels comprising three or more walls.

In this positive example from US2002023926, three walls are counted.

Pressure vessels for which the wall's or layer's material is defined.

Material of exterior arrangement, insulation, assembling means, connecting components etc. are not considered.

Pressure vessels for which the wall's or layer's material comprises metal.

Pressure vessels for which the wall's or layer's metal comprises steel, that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight.

Pressure vessels for which the wall's or layer's material comprises non-magnetic steel.

Pressure vessels for which the wall's or layer's material comprises stainless steel.

Pressure vessels for which the wall's or layer's material comprises aluminium.

Pressure vessels for which the wall's or layer's material comprises an alloy, or for which a composition of the metal is disclosed.

Only alloys for which another groups are not foreseen are classified here.

Metals designated as "alloy" in the text, without revealing the exact composition, are classified here.

Alloys, for which the composition is revealed, are classified here, and in the group of the composing metal. Example: Al3Cr2Mg is classified as alloy and as aluminum.

The revelation of the composition of an alloy can be in any form: chemical formulae, by volume, by weight etc.

Pressure vessels for which the wall's or layer's material comprises FeNi36 or 64FeNi (US), known as Invar, a nickel steel alloy notable for its uniquely low coefficient of thermal expansion and resistance to cryogenic temperatures.

Pressure vessels for which the wall's or layer's material comprises lead (Pb).

Pressure vessels for which the wall's or layer's material is made of metal filaments.

In this positive example from GB48534, a metal filament winding forms a layer.

In this negative example from GB1518156, individual metal filaments do not form a layer.

Pressure vessels for which the wall's or layer's material is synthetic

Pressure vessels for which the wall's or layer's synthetic material comprises plastics.

Pressure vessels for which the wall's or layer's synthetic material is made of fibers or filaments.

In this positive example from EP0744274, a synthetic filament winding forms a layer.

Pressure vessels on which fibers or filaments are wound at right angle to the main axis of the vessel.

In this positive example from GB48534, filaments are radially wound around the middle part of the cylinder.

Pressure vessels on which fibers or filaments are wound in a way aligned with the main axis of the vessel.

In this positive example from US2009308874, filaments are axially wound around the middle part of the cylinder.

In this positive example from WO0157429, filaments are axially and radially wound.

Pressure vessels on which fibers or filaments are helically wound.

In this positive example from GB2253041, filaments are helically wound.

Pressure vessels on which fibers or filaments are embedded in a polymer.

In this positive example from WO03016777, fiber are embedded in a resin matrix.

Pressure vessels for which the composition of the wall's or layer's synthetic material is disclosed.

The revelation of the composition can be in any form: chemical formulae, by volume, by weight etc.

Pressure vessels for which the wall's or layer's material comprises concrete or cementitious materials.

Pressure vessels for which the wall's or layer's material is made of a fluid in liquid or gaseous form.

In this positive example from GB1343187, a pressurized liquid fills the free space.

In this negative example from EP0624752, a gaseous thermal insulation surrounds the vessel.

This is no load-bearing layer in the sense of the definition of "layer".

Pressure vessels for which the wall's or layer's material is flexible.

In this positive example from GB2435505, the whole vessel is flexible.

In this negative example from US4982870, the shape of the vessel is flexible, but not the material.

Pressure vessels for which the wall's or layer's material is superconducting.

Pressure vessels for which the wall's or layer's material comprises a break point, i.e. an intentionally weakened section supposed to break first at overpressure or when punctured.

In this positive example from GB2080436, a weakened tab member is located at the bottom section.

In this positive example from WO2004113787, a weakened part is located at the top section.

Pressure vessels for which the wall's or layer's material is transparent.

In this positive example from US4589562, a transparent layer allows to consult the label underneath.

Pressure vessels for which the wall's or layer's material is pre-constrained.

In this positive example from WO9935036, the inner layer is pre-constrained.

Pressure vessels for which the wall's or layer's material comprises nanoparticles, usually sized between 1 and 100 nanometers.

Means related to the stand or mounting of pressure vessels, to devices attached to it or in fluid connection with it, and to identification means.

Mounting arrangements allow the mounting of the pressure vessel but are not necessary for the structural integrity of the vessel, i.e. to avoid its bursting.

Mounting arrangements external to the pressure vessels.

Exterior arrangement in form of an external frame, usually for protection or transport.

In this positive example from EP1522786, a frame surrounds the vessel.

Exterior arrangement in form of an box in which the pressure vessel is contained, usually for protection or transport.

In this positive example from US4523548, 3 pressure vessels are mounted inside a common box.

Exterior arrangement in form of a dismountable hull to protect the vessel e.g. made out of neoprene, to protect from impacts.

In this positive example from US2001037549, two sections of composite fiber protect the vessel from bumps.

In this positive example from DE102007006047, the hull is welded and thus not dismountable.

Exterior arrangement which is also part of the vessel, the vessel wall itself fulfilling a double function: containing the fluid and constituting the external structure in which the vessel is mounted, e.g. a wing of a plane being at the same time the liquefied fuel tank.

In this positive example from EP1431096, the car frame is a vessel wall.

In this positive example from US3640237, the ship hull is a vessel wall.

Count of the number of pressure vessels and their external arrangements

Count of one single pressure vessel and its external arrangement.

In this positive example from EP1150059, a single spherical vessel is held in a frame.

In this negative example from BE471532, there is no exterior arrangement.

Count of two or more pressure vessels and their external arrangements.

In this positive example from US4523548, 3 pressure vessels are mounted inside a common box.

Count of two or more pressure vessels comprising at least one fluid connection.

In this positive example from US2005205137, several cylindrical pressure vessels are connected by several fluid connections.

In this negative example from EP1150059, no fluid connection is established.

In this negative example from DE4009248, the aligned cartridges are not in fluid connection.

Two or more pressure vessels in which the fluid connection is a serial fluid connection.

In this positive example from FR1222726, fluid from the right vessel needs to pass into the first vessel.

In most cases, there is no clear serial connection, so that generally, only the word "series" in the text can trigger classification in this group.

Two or more pressure vessels in which the fluid connection is a fluid connection in parallel.

In this positive example from DE3024251, fluid can be filled into or emptied from each vessel independently.

In most cases, there is no clear parallel connection, so that mainly the word "parallel" in the text triggers classification in this group.

Fluid connection between several vessels with a manifold, wherein details of the manifold (e.g. single valves, detailed connections, way of distributing fluid) are visible or explained.

In this positive example from US2007215209, the inner structure of the manifold is defined.

Arrangement of two distinct pressure vessels, in which one vessel is mounted inside the other and in which each vessel could have be operated as an independent vessel in terms of withholding the internal pressure. Each vessel contains fluid to be stored, and not a fluid for another purpose like insulation. The fluid contained in the different vessels can be different.

In this positive example from US1692670, two clearly distinguishable cylindrical vessels are mounted one inside the other.

In this negative example from GB2249377, the same fluid occupies a single vessel separated in several chambers. There are no independent vessels.

In this negative example from GB412814, the common wall of both chambers is dominant.

Each independent vessel has to be considered separately with regard to its wall structure (number of layers, material etc...).

Vessels that share a common wall have to be considered individually: if the common wall is dominant, than a classification herein is not necessary; if the common wall is not extended, an independent vessel can be defined and classified herein.

A device that indicate a specific way of transporting the vessel.

In this positive example from FR1281179, cavities for forks or for a forklift are foreseen.

In this positive example EP1643182, it is explained that the form is ergonomic so as to easily lift the vessel by hand.

In this negative example from EP0034555, a small cartridge is, by its size, easy to lift by human force and easy to transport, but there is not specific device that suggests a certain mode of transport.

The device for transport comprising wheels

In this positive example from US2006261567, wheels can be attached to the vessel.

Specific vehicles with wheels like e.g. trailers and trucks transporting pressure vessels are classified in groups in F17C 2270/0165.

The device for transport comprising a handgrip.

In this positive example from NL7906614, the handgrip is on the vessel.

In this positive example from WO0111285, the handgrip is mounted on a transporting box.

A device allowing to stack vessels or groups of vessel upon each other.

In this positive example from US2010186426, a specific frame allows to stack groups of vessel.

In this positive example from DE20010514U, a stacking device is mounted on the protection cap and fits with the mounting feet at the bottom of the vessel.

In this negative example from US4846088, the pressure vessels are piled on a ship, but without any detailed indication about a stacking device.

A device, e.g. a lock, preventing access to or removal of one or several vessels.

In this positive example from GB2171785, a safety lock holds a protective cap on the vessel.

In this positive example from US2007109068, access to the vessel is prevented by a lock on a box.

A device, e.g. a ventilator or ventilation openings, that support ventilation of the room or box in which the pressure vessel is stored.

In this positive example from EP1037269, two ventilators are mounted in the box wall.

In this negative example from WO2007048953 a vent valve is mounted on the vessel, but not on a room or box in which the pressure vessel is stored.

A device directly on the pressure vessel allowing an upright or lying fixed stable position.

In this positive example from GB412814, mounting feet are placed below a spherical vessel.

In this positive example from EP0826433, the bottom of the pressure vessel is formed so as to allow a stable upright position.

In this negative example from DE19952611, the flat bottom of the pressure vessel would allow an upright position, but there is no form that suggests mounting feet.

A device allowing not only positioning of the pressure vessel to the ground but an attaching, mooring or anchoring.

In this positive example from DE2447246, the vessel is attached to the sea ground.

In this positive example from US6345933, the vessel is attached to the ground by ropes

In this negative example from DE2633607, the supporting elements are not anchored to the ground.

A device allowing hanging up and lifting of the vessel.

In this positive example from DE20204336U, the vessel is hung up with crooks.

In this negative example from GB2440350, the inner vessel is hung in the outer vessel by suspension means.

Hanging up one vessel inside another is dealt with in F17C 2203/014, "suspension means".

A device allowing to maintain the vessel in an external structure.

In this positive example from EP1060936, the vessel can be attached into a vehicle by screws.

In this positive example from WO2010020431, circumferential bearing means hold the vessel upright.

A device comprising means absorbing shocks.

In this positive example from US2011147390, a shock absorbing padding is placed at the bottom of the tank.

Devices through which the fluid contained in the vessel flows or may flow.

Bosses and boss collars for which details related to the mounting, the sealing or the attachment to the vessel are available.

In this positive example from US2010072209, boss and boss collar are detailed.

Device for protecting the boss of a pressure vessel, and the valves mounted thereon, from impact. This device can be a prolonged part of the vessel wall.

In this positive example from BE1006503, the protection is flat.

In this positive example from FR1120882, the protection surrounds the valve.

Device for permanently closing the vessel openings, allowing only exceptionally an opening

In this positive example from FR1435928, a closure device is mounted on the vessel.

In this positive example from GB291061, a closure device is screwed on the vessel.

Closure means with a weakened zone bursting when a limit pressure is reached.

In this positive example from US4219126, the closure mean ruptures at a thinner weak zone

Closure means with a heat sensitive zone fusing or melting when a limit temperature is reached.

In this positive example from US2004159352, a melting device is placed in a manifold.

Closure means with a weakened zone to be easily pierced or punctured.

In this positive example from EP0155407, the cartridge discloses a zone to be punctured by a needle.

Valves through which the fluid contained in the vessel flows or may flow.

Valves related to other processes, like the cooling process, are not classified.

Valves with electrical actuation, usually a solenoid.

In this positive example from EP1990568, a solenoid valve is disclosed.

Valves with a manual actuation.

In this positive example from BE716158, the manual actuation is materialized by a handle on top.

Valves the opening of which is triggered by dangerous state of the fluid, usually overpressure.

In this positive example from EP1318347, gas is evacuated at overfilling.

Valves that prevents fluid flow in a certain direction.

In this positive example from US2004123735, the fluid can only flow out through the branch with the check-valve.

Regulators for pressure with a set point and means to stay at it.

In this positive example from WO0201306, a pressure regulator is mounted inside the vessel.

Filters for purifying the stored fluid.

In this positive example from US4111661, a filter is mounted inside the vessel.

Filters of the sintered type, like sintered bronze, often used in applications requiring high temperatures resistance.

Filters of the active carbon type with extremely porous activated carbon for absorption or chemical reaction to enable high quality filtering.

Devices to reduce flow of the fluid, like restrictors or throttles.

In this positive example from US2005028536, flow is reduced.

In this positive example from EP1445622, a capillary stem restricts the flow of hyperpolarized gas.

Pipes for which details are available.

In this positive example from US2006254676, details of the pipes are visible, in particular the bending and the parts located in the vessel and at the pressure vessel inlet.

In this negative example from EP0908665, no details about the pipe are visible. In purely functional drawings, pipes are often represented symbolically as a line between two points, without any details.

Pipes with a thermal insulation.

In this positive example from US2235424, the pipe is insulated.

In this negative example from US2005211711, the pipes run through the vessel and insulate the fluid inside the vessel.

The convenient subclass is "Thermal insulation by liquid means (F17C 2203/037)".

Pipes mounted inside another one

In this positive example from US3355893, several coaxial pipes reach into an underground vessel.

Pipes with a ripped outer or inner surface.

In this positive example from US2007186925, a ripped pipe is directly mounted on the vessel.

Pipes which, in use, can take several locations due to the flexibility of the material or due to articulations.

In this positive example from DE19910894, the pipe follows the fluid level in the vessel.

In this positive example from WO2005032942, the pipe adapts to the movement between ship and mooring buoy.

Pipes functioning in parallel, one being an inflow (usually liquefied gas), the other a backflow line (usually gas).

In this positive example from EP0889274, a liquefied fluid pipe and a gas pipe run in parallel and are located in parallel.

In this positive example from WO2006008299, a liquid hose and a vapor hose run in parallel.

In this positive example from EP2236904, a LNG pipe and a gas pipe run in parallel.

Means to quickly connect two devices so as to transfer fluid.

In this positive example from DE29711842U, a coupling allows to branch to a pipe.

In this negative example from EP1099664, the coupling has the form of dispensing pistols.

Quick connecting means in form of a dispensing coupling are classified with "Dispensing pistols" in F17C 2205/0376

Adapter to be located between means to connect two coupling devices, these means being for example a quick coupling means or a dispensing pistol.

In this positive example from EP1099664, an adapter is mounted on a dispensing pistol.

Means to quickly connect two devices so as to transfer fluid, the means having the form of a pistol, with the typical pistol bend.

In this positive example from EP1669663, the dispensing pistol is for liquefied gas.

Quick connecting means in form of a dispensing coupling which have not the typical pistol bend are classified with "quick connecting means" in F17C 2205/037

Pressure vessels comprising an access to the inner space for maintenance or inspection, no matter whether the access is dimensioned for a whole person or for a hand.

In this positive example from EP1522786, a manhole is situated on top of the vessel.

In this negative example from DE69723389T2, a manhole provides access to the protective concrete surrounding, not the vessel itself.

All vessels have an access to the inside. Those accesses that justify a classification herein should explicitly be designed for that purpose, e.g. maintenance or inspection should be mentioned in the text, or a ladder should be placed next to the access.

Valves or regulators for which details of the internal mechanisms are visible, which are thus not represented as functional drawings, but rather as workshop drawings or cut views.

In this positive example from FR847127, the valve seat, the spring, and a solenoid are visible.

In this negative example from US2003010395, valves are only represented as symbol.

Compact unit comprising several valves or regulators mounted en bloc.

In this positive example from FR2798450, one single body holds 5 types or valves.

In this negative example from EP1726869, a sequence of valves seems mounted close to the vessel, but there is no single unit.

Localisation of valves, regulators or filters in the gas storage or handling process.

Localisation of valves, regulators or filters at least partially inside the pressure vessel.

In this positive example from US5197710, the insertion of the valve is partial.

In this positive example from WO0181822, the pressure regulator is mounted entirely inside the vessel

Localisation of valves, regulators or filters on or in direct contact with the pressure vessel.

In this positive example from BE471532, the valve is mounted on the vessel.

In this negative example from DE10058496, the valves marked in red are placed on the pipe, only one valve directly mounted on the pressure vessel could be classified here.

Localisation of valves, regulators on two opposed or distant sides of the pressure vessel.

In this positive example from EP0753700, two openings are situated at opposite locations on the vessel.

In this positive example from DE19937470, openings are situated at opposite locations on the vessel and on the middle part

In this negative example from FR2067600, the main opening is flanked by two secondary openings.

The presence of appropriate openings, within the explicit presence of valves or regulators, is sufficient to allow a classification here.

An opening which is not on an opposed or at least distant localisation on the vessel is not classified herein.

Devices carrying information about the content of the vessel or the vessel itself.

In this positive example from FR2849606, a maintenance report is attached to vessel.

Devices using coating to carry the information.

In this positive example from US2007164040, the gas type is marked on the vessel.

Coating which has not role in carrying information like e.g. coating that serves for protection against mechanical impact, is not classified here, but only under F17C 2203/0607

Devices using a sticker to carry the information.

In this positive example from WO8504380, a label is placed between two layers.

Devices using bar codes to carry the information.

In this positive example from EP0515184, a bar code is attached to the valve.

Devices using magnetic means to carry the information.

In this positive example from WO2007042879, an electromagnetic tag is attached at the neck of the vessel.

Devices using electronic chips to carry the information.

In this positive example from FR2868186, information carried on chips can be transmitted.

Devices using RFID to carry the information.

In this positive example from EP1988327, RFID allows transmitting information over longer distances.

Manufacturing steps or manufacturing method for pressure vessels.

In this positive example from WO03031860, several manufacturing steps of a cylindrical vessel are illustrated.

In this negative example from GB2096299, round corners appear, but are not sufficient to deduct any manufacturing method like moulding.

Ideally, manufacturing steps or methods are explicitly disclosed. Alternatively the vessel must be described in a way indicating how it has been manufactured e.g. "blow-moulded vessel".

Manufacturing steps or manufacturing method for pressure vessels during which material is put into a certain shape.

Manufacturing steps or manufacturing method for pressure vessels comprising moulding, e.g. applied to plastics or metal.

Manufacturing steps or manufacturing method for pressure vessels comprising injection moulding, during which heated material is forced into a mould cavity where it cools and hardens.

Pressure vessel for which blow moulding is disclosed as manufacturing step, usually to form hollow elements, consisting in forcing heated material into a mould cavity where it cools to form hollow parts.

Manufacturing steps or manufacturing method for pressure vessels using wax moulds, which are lost after the process.

Manufacturing steps or manufacturing method for pressure vessels comprising rotation moulding, causing the material to disperse and stick to the mould walls.

Manufacturing steps or manufacturing method for pressure vessels comprising winding

In this positive example from US5202165, details of the winding step are visible.

In this negative example from US2011210131, a wound pressure vessel is disclosed without details of the manufacturing process.

The term "wound" or "winding" is per se not sufficient to materialize a manufacturing step. A wound pressure vessel is classified under

F17C 2203/0663. Manufacturing steps or a manufacturing method details how the pressure vessel is wound is required to classify herein.

Manufacturing steps or manufacturing method for pressure vessels comprising winding with a mandrel, which is removed after the process.

In this positive example from US6189723, the removable mandrel is visible.

In this negative example from FR2575966, the winding takes place around a liner, which is not removed afterwards.

Manufacturing steps or manufacturing method for pressure vessels comprising a form of polishing, e.g. by sand blasting.

Manufacturing steps or manufacturing method for pressure vessels comprising a metal working process, like deep drawing, stamping or cutting.

In this positive example from US4023696, a punch forms metal into a vessel.

Manufacturing steps or manufacturing method for pressure vessels comprising a non-metal working process, like extruding.

In this positive example from WO0236333, a polymeric vessel is formed by extruding.

Manufacturing steps or manufacturing method for pressure vessels during which material parts are assembled to complete the vessel.

Unless particularly interesting and exceptional assembling steps are detailed, the mounting of valves on the vessel should not be classified herein.

Manufacturing steps or manufacturing method for pressure vessels during which material parts are assembled by welding

In this positive example from WO8900658 weld spots are visible in a drawing.

As there is no other classification entry related to welding, an explicit welding manufacturing step is not necessary, so that the term "welded" or the presence of welding spots on drawings are sufficient for classification in this group.

Manufacturing steps or manufacturing method for pressure vessels during which material parts are assembled by friction welding.

In this positive example from WO2004096459, several parts are assembled by friction welding at the same time.

Manufacturing steps or manufacturing method for pressure vessels during which material parts are assembled by press- or shrink-fitting.

In this positive example DE8619754U, fitted parts of the middle part are slightly conical.

Manufacturing steps or manufacturing method for pressure vessels during which material parts are sprayed.

In this positive example from US2004089440, glue is sprayed.

Manufacturing steps or manufacturing method for pressure vessels during which material parts are assembled by adhesive means like glue.

In this positive example from WO02088593, layers are glued together.

In this negative example from WO0148418, fibers in a layer are adhered by a matrix material, but this is not considered an assembling step.

Manufacturing steps or manufacturing method for pressure vessels during which material parts are assembled by screws or bolts or rivets.

In this positive example from DE671013, a screw holds parts of the vessel together.

In this negative example from US2372800, two parts of a vessel are screwed together. This example is classified in "assembling processes"

Particular details or locations in relation with manufacturing steps or manufacturing method for pressure vessels.

Any details related to a way of assembling walls or layers, like the presence of welding spots, the placing of an O-ring or a way to fold metal in the contact zone, are classified herein.

A manufacturing process step does not need to be explicitly mentioned, in most cases, a drawing with a detail is sufficient.

Details in relation with the assembling of walls or layers.

In this positive example from WO9220954, a layer is assembled with a certain angle.

In this positive example from EP0166492, the layer has a honeycomb structure.

In this positive example from WO2010112715, layers are maintained by an H-profiled element.

Details in relation with the assembling of end pieces.

In this positive example from WO03031860, the mounting steps of closing end pieces is illustrated.

In this positive example from US2011253727, the form of the edge of the end piece is detailed.

Apparatus related to the assembling of end pieces and to the inserting of valves.

In this positive example from EP0780191, the focus is on the mounting apparatus, not on the vessel.

Details in relation with the filling of insulant into a wall, e.g. insertion and compression of perlite.

In this positive example from WO2010039198, Aerogel is added to an insulating layer.

Fluid stored in the pressure vessel or handled during charging or discharging into or from a pressure vessel.

In this positive example from WO2010039198, the fluid stored in the tank is hydrogen.

Fluids not being the primary fluid to be stored in the tank, e.g. fluids for insulation layers, are not classified herein.

Mixtures of different fluids are classified in all relevant classes into which each fluid composing the mixture would be classified, and additionally into the class "Mixtures", e.g. a mixture of He and O2 are classified in the classes related to Helium , Oxygen, and "Mixtures".

Fluid represented by a single sort of molecules, or mixture containing at least one fluid represented by a single sort of molecules.

Fluid comprising oxygen (O₂).

Fluid comprising hydrogen (H₂).

Fluid comprising carbon dioxide (CO₂).

Fluid comprising nitrogen (N₂).

Fluid comprising carbon monoxide (CO).

Fluid comprising mono-atomic fluids with very low chemical reactivity, like), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe) or radon (Rn).

Fluid comprising Helium (He).

Fluid comprising acethylene (C₂H₂).

Fluid represented by a mixture of molecules or mixture containing at least one fluid represented by a mixture of molecules.

Fluid comprising air (4/5 nitrogen, 1/5 oxygen, argon and traces of carbon dioxide).

The constituents of air, like oxygen or nitrogen are not additionally classified in the relevant classes

Hydrocarbon, composition of carbon and hydrogen atoms, of the type CmHn.

Hydrocarbon entirely or essentially made of methane CH₄, but generally comprising also ethane and higher hydrocarbons.

Natural gas is generally rather defined by its heat value than by its composition.

Hydrocarbon entirely or essentially made of propane C₃H₈ or butane C₄H₁₀, but generally comprising also some higher or lower hydrocarbons.

Fluid comprising hydrates, a mixture of hydrocarbon and water.

Fluid comprising toxic or pollutant substances, like chlorine.

Fluid stored or transferred is a refrigerant.

In this positive example from EP1333223, Chlorodifluoromethane or ,1,1,2-Tetrafluoroethane is stored in the tank.

In this negative example from US2003159800, the refrigerant is not the fluid stored in the vessel, but in an attached refrigerating system.

Fluid cleaned of bacteria, particles. organic and inorganic substances, often used in the semiconductor manufacturing process.

Gas in an hyperpolarized state (ionised, having a negative potential).

Combustion fluid or propellant for rockets or space vehicles, e.g.N₂H₄.

Particular characteristics of the fluid stored in the pressure vessel or before transfer into the pressure vessel.

If a network of pressure vessels, the fluid in each pressure vessel and the transfer into each pressure vessel have to be considered separately and eventually classified.

E.g.: if a vessel 1 is emptied into a vessel 2, vessel 1 may be considered for classification into F17C 2223/00 and its sub-groups, and vessel 2 has to be considered for classification into F17C 2225/00 and its sub-groups. Finally, actual classification should only take place if "interesting", specific or unconventional transfer processes are disclosed.

Phase of the fluid stored in the pressure vessel or before transfer from the pressure vessel.

Fluid stored in the pressure vessel or before transfer from the pressure vessel is in a single phase.

The single phase of the fluid stored in the pressure vessel or before transfer from the pressure vessel is dense or supercritical, i.e. at a temperature or pressure above the critical point, where no distinction between liquid or gas exists.

In this positive example from US2003115889, natural gas is in dense phase.

The single phase of the fluid stored in the pressure vessel or before transfer from the pressure vessel is gaseous.

In this positive example from US201007229, compressed hydrogen gas is stored.

The single phase of the fluid stored in the pressure vessel or before transfer from the pressure vessel is liquid.

Fluids in liquid form, other than "gas" in the sense of the definition for this subclass, should not be classified in F17C. Some documents though may appear in which the liquid form is present e.g. a vessel filled completely with pure subcooled gas.

The single phase of the fluid stored in the pressure vessel or before transfer from the pressure vessel is solid.

In this positive example from WO2011093786A1, a solid block of CO₂ is placed into the vessel during manufacturing.

Fluids in solid form, other than "gas" in the sense of the definition for this subclass, should not be classified in F17C. Some documents though may appear in which the solid form is present.

Fluid stored in the pressure vessel or before transfer from the pressure vessel is in a two-phase state.

The two-phase state is liquid and gaseous, and the fluid concerned can be liquefied at high pressure under normal temperatures, like butane or propane.

In this positive example from DE102004044259, liquefied propane is stored.

The two-phase state is liquid and gaseous, and the fluid concerned is in liquid state at cryogenic temperature, like oxygen, hydrogen or natural gas.

In this positive example from WO2010039198, liquefied hydrogen is stored.

The liquid and gaseous two-phase state is additionally sub-cooled, i.e. at a temperature lower than saturation temperature.

In this positive example from EP1353112, liquid CO₂ is subcooled.

The two-phase state is solid and gaseous, like CO₂ dry ice.

In this positive example from WO9403288, solid carbon dioxide sublimates.

The two-phase state is solid and liquid, like hydrates.

Fluid stored in the pressure vessel or before transfer from the pressure vessel is in a three-phase state, i.e. at the triple point.

In this phase diagram extracted from Wikipedia, the triple point is visualised.

Pressure of the fluid stored in the pressure vessel or before transfer from the pressure vessel.

The rule of classification, according to which a technical feature has to be explicitly mentioned, is not strictly applicable here: pressure can be estimated, if there are sufficient hints.

The boundaries indicated in the groups (1 bar, 10 bars, 80 bars) are merely to be understood as an indication and an order of magnitude. They are not binding or strict.

In doubt, it might be useful to classify into two adjacent classes (high pressure and very high pressure, high pressure and small pressure, or small pressure and not under pressure) simultaneously.

Hints allowing to estimate pressure can be in the drawings, like the thickness of the vessel wall, or knowledge from the context or the application the fluid is used in.

The pressure is very low, around 1 bar absolute, or the vessel is not under pressure, open and in direct contact with the environment.

In this positive example from EP2103863, liquid oxygen is stored under lowest pressure.

The pressure is low, from 1 to 10 bars absolute, or the pressure vessel contains liquefied gas and is submitted to its vapor pressure.

The pressure is high, from 10 bars to 80 bars absolute.

The pressure is very high, above 80 bars absolute.

The pressure is sub-atmospheric, e.g. when vacuum is intentionally maintained in the pressure vessel.

Fluid within one phase discloses different layers e.g. liquefied gas which is sub-cooled in the lower layers of the liquid phase, and at saturation temperature in the higher layers of the liquid phase.

In this positive example from WO9941164, stratification is obtained in a gaseous fluid.

In this positive example from JP59019800, liquefied gas stratifies in two layers.

In this negative example from WO0134235, a liquid phase is topped by the vapor phase. Each phase is homogeneous.

Fluid removal point with a particular location or position.

In this positive example from CH239535, the upper removal tube is bent upwards in a detailed drawing.

In this positive, more schematic example from WO0134235, a tube is prolonged inside the liquid in the vessel.

Only documents in which the vessel contains at least two phases of the fluid should be classified. There is no need to classify a removal point in the gas for a vessel in which there is nothing else than gas.

Fluid removed is gas only or removal point is situated in the gas phase.

In this positive example from FR2607575 the removal tube's end is located on top of the vessel.

Gas is removed through a tube that extends into the vessel through the liquid phase.

In this positive example from CH239535, the upper tube reaches the gas phase through the liquid phase.

Fluid removed is liquid only or removal point is situated in the liquid phase.

In this positive example from DE102005002976, liquid carbon dioxide is removed from the bottom of the vessel.

Liquid is removed through a tube that extends into the vessel through the gas phase.

In this positive example from WO2007107509, liquefied natural gas is removed with a dip tube.

Fluid removed is solid only or removal point is situated in the solid phase.

Particular characteristics of the fluid after being transferred.

In this positive example from EP1846691, the handled fluid after transfer is gaseous.

If a network of pressure vessels, the discharge from each pressure vessel has to be considered separately and eventually classified.

E.g.: if a vessel 1 is emptied into a vessel 2, vessel 1 may be considered for classification into F17C 2223/00 and its sub-groups, and vessel 2 has to be considered for classification into F17C 2225/00 and its sub-groups. Finally, actual classification should only take place if "interesting", specific or unconventional transfer processes are disclosed.

Consult also F17C 2223/00

Phase of the fluid after being transferred.

Fluid after being transferred is in a single phase.

The single phase of the fluid after being transferred is dense or supercritical, i.e. at a temperature or pressure above the critical point, where no distinction between liquid or gas exists.

In this positive example from US2003115889, natural gas is in dense phase.

The single phase of the fluid after being transferred is gaseous.

In this positive example from CH209041, gas is transferred.

The single phase of the fluid after being transferred is liquid.

Fluids in liquid form, other than "gas" in the sense of the definition for this subclass, should not be classified in F17C. Some documents though may appear in which the liquid form is present e.g. a vessel filled completely with pure subcooled gas

The single phase of the fluid after being transferred is solid.

Fluids in solid form, other than "gas" in the sense of the definition for this subclass, should not be classified in F17C. Some documents though may appear in which the solid form is present.

Fluid after being transferred is in a two-phase state.

The two-phase state is liquid and gaseous, and the fluid concerned can be liquefied at high pressure under normal temperatures, like butane or propane.

In this positive example from WO2005058684, liquefied gas is transferred without phase change.

The two-phase state is liquid and gaseous, and the fluid is liquefied under cryogenic temperatures, like oxygen, hydrogen or natural gas.

The two-phase state is liquefied gas, and the fluid phase is additionally sub-cooled, i.e. at a temperature lower than saturation temperature.

The two-phase state is solid and gaseous, like CO₂ dry ice.

The two-phase state is solid and liquid, like hydrates.

Fluid after being transferred is in a three-phase state, i.e. at the triple point.

Pressure of the fluid after being transferred.

The rule of classification, according to which a technical feature has to be explicitly mentioned, is not strictly applicable here: pressure can be estimated, if there are sufficient hints.

The boundaries indicated in the groups (1 bar, 10 bars, 80 bars) are merely to be understood as an indication and an order of magnitude. They are not binding or strict.

In doubt, it might be useful to classify into two adjacent classes (high pressure and very high pressure, high pressure and small pressure, or small pressure and not under pressure) simultaneously.

Hints allowing to estimate pressure can be in the drawings, like the thickness of the vessel wall, or knowledge from the context or the application the fluid is used in.

The pressure is very low, around 1 bar absolute, or the vessel is not under pressure, open and in direct contact with the environment.

The pressure is low, from 1 to 10 bars absolute, or the pressure vessel contains liquefied gas and is submitted to its vapor pressure.

The pressure is high, from 10 bars to 80 bars absolute.

The pressure is very high, above 80 bars absolute.

The pressure is sub-atmospheric, e.g. when vacuum is intentionally maintained in the pressure vessel.

Fluid within one phase discloses different layers e.g. liquefied gas which is sub-cooled in the lower layers of the liquid phase, and at saturation temperature in the higher layers of the liquid phase.

Fluid filling point with a particular location or position.

Only documents in which the vessel contains at least two phases of the fluid should be classified. There is no need to classify a filling point in the gas for a vessel in which there is nothing else than gas.

Fluid filling point is situated in the gas phase.

In this positive example from US2008141684, the filling tube's is located in the gas phase.

Fluid is filled at several filling points, and condenses at the same time surrounding gas vapor.

In this positive example from WO2008099977, filling takes place at several points in the gas phase, where recondensation takes place.

Gas is filled through a tube that extends into the vessel through the liquid phase.

In this positive example from US2008141684, the upper tube reaches the gas phase through the liquid phase.

Fluid filling point is situated in the liquid phase.

In this positive example from US5404918 the filling tube's end is located on bottom of the vessel.

Liquid is filled through a tube that extends into the vessel through the gas phase.

In this positive example from FR2607575 the filling tube's end is located on the bottom of the vessel.

Fluid filling point is situated in the solid phase.

Methods or means for transferring fluid out of or into a pressure vessel. Method or means for achieving thermal exchange with fluid stored in or transferred out of or into a pressure vessel.

Methods or means for transferring fluid out of or into a pressure vessel.

In this positive example from US2836963, the pressure vessel contains a piston.

In this negative example from BE471532, fluid is discharged after opening the valve.

When the valve of a pressurized vessel is opened, fluid flows by pressure difference out of the vessel. This standard discharge of a pressure vessel is not classified, unless additional features make the discharge more specific.

Propulsion means like pumps or compressors are to be classified in relevant classes.

Methods of transferring liquefied gas out of a pressure vessel by raising the pressure of the vapor phase (the ullage), so that the vapor phase pushes on the liquid surface. The pressure raise is often operated by vaporizing part of the liquefied gas with a heater.

In this positive example from US2007186925, a heating element evaporates liquefied gas in the vessel.

In this negative example from US2007017596, an external purge gas replaces the vapor phase. Though gas is added in the ullage, the purpose is not to specifically to discharge the vessel.

Any vessel containing liquefied gas is subject to a pressure rise when heat influx takes place. Only those documents are classified herein in which the pressure rise serves specifically the purpose of discharging the vessel.

Methods of transferring fluid out of or into a pressure vessel by using vacuum created by a vacuum injector, e.g. venturi type.

In this positive example from US2007261756, extraction takes place by a venturi pump.

Methods of transferring fluid by gravity out of a pressure vessel, the weight of the fluid itself discharging the vessel.

In this positive example from EP1770326, an exit is simply mounted on the bottom of the vessel.

Methods of transferring out of or into a pressure vessel fluid by using pumps or compressors.

Pumps generally are used for the liquid phase and compressors for the gas phase. This rule should be followed for classification. Though, the distinction is not always clear, e.g. for supercritical fluid, for which both terms are used.

Methods of transferring liquid fluid out of or into a pressure vessel, by using pumps.

In this positive example from WO9709561, a pump is immersed in the vessel.

Methods of transferring liquid fluid out of or into a pressure vessel by using a pump, the type of which is specified, e.g. of piston type.

In this positive example from US3426545, a piston type pump is used.

Methods of transferring liquid fluid out of or into a pressure vessel using pumps, wherein the pump is cooled.

Methods of transferring gas out of or into a pressure vessel using a compressor.

In this positive example from DE102009039645, a compressor compresses gas from the tank.

Methods of transferring gas out of or into a pressure vessel using a compressor, the type of which being specified, e.g. piston type.

In this positive example from US2003021743, a high pressure piston compressor is used.

Special localization or configuration of pumps or compressors used to transfer fluid out of or into a pressure vessel.

Localization of pumps or compressors used to transfer fluid out of or into a pressure vessel inside a vessel.

In this positive example from FR2722760, the pump is immersed.

Configuration of pumps or compressors used to transfer fluid out of or into a pressure vessel, in which several pumps or compressors are used or usable.

In this positive example from US2006150640, three pumps transfer cryogen.

Methods of transferring fluid out of or into a pressure vessel using a working fluid. This working fluid replaces and pushes the fluid to be transferred. The working fluid may be in direct contact with the fluid to be transferred or separated by an element like a membrane or a piston. The working fluid is different from the transferred fluid.

In this positive example from DE29816811U, a piston separates the working fluid from the gas.

In this negative example from US2007186925, the vaporized fluid itself pressurises the ullage and pushes the liquefied gas.

Transfer or gas by pressurizing the ullage should be classified in F17C 2227/0107

Method or means for achieving thermal exchange with fluid transferred, the thermal exchange being heating or cooling, direct or indirect or via intermediate fluids, and taking place anywhere.

In this positive example from US20070186564, the part of the scheme related to the actual process gas is restricted to one heat exchanger 114.

The terms "heating" or "cooling" are defined with regard to the classified process gas only.

"Heating" means that heat is transferred to the gas. "Cooling" means that heat is transferred from the gas.

Heating or cooling of external fluid carriers like intermediate fluids are not classified herein.

Method or means for heating fluid transferred out of or into a pressure vessel.

In this positive example from US2007186925, a heating element heats and evaporates liquefied gas in the vessel.

Method or means for heating fluid by an electrical heater.

In this positive example from DE102005049252, an electrical heater is mounted on a pipe inside the vessel.

Method or means for heating fluid by using the same fluid as the fluid transferred.

In this positive example from WO2005045337, the gaseous and the liquid phase of the fluid exchange heat in an external heat exchanger, the one being heated, the other cooled.

Method or means for heating fluid, the heat being obtained from another fluid than the fluid transferred.

In this positive example from US4995234, liquefied carbon dioxide exchanges heat with the LNG.

Method or means for heating fluid , the heat being obtained from air.

In this positive example from US2007132116, air is used to vaporize LNG.

The heat source has to be considered, even if there are other intermediate heat carrying fluids.

If the heat source is air, then the document has to be classified herein.

Method or means for heating fluid, the heat being obtained from air in a forced circulation, e.g. by using a ventilator.

In this positive example from EP1724514, air is ventilated onto LNG.

Method or means for heating fluid, the heat being obtained from water.

In this positive example from US2006288711, water vaporizes the LNG.

The heat source has to be considered, even if there are other intermediate heat carrying fluids.

If the heat source is water, then the document has to be classified herein.

Method or means for heating fluid, the heat being obtained from seawater.

In this positive example from US2006288711, seawater vaporizes the LNG.

The heat source has to be considered, even if there are other intermediate heat carrying fluids.

If the heat source is seawater, then the document has to be classified herein

Method or means for heating fluid, the heat being obtained from geothermal water.

In this positive example from US2007079617, geothermal water vaporizes the LNG.

The heat source has to be considered, even if there are other intermediate heat carrying fluids.

If the heat source is geothermal water, then the document has to be classified herein

Method or means for heating fluid, the heat being obtained from another fluid that circulates in a closed loop. This other fluid is often an intermediate heat carrying fluid, like propane or an alcohol, chosen so as not to freeze in contact with the cryogen.

In this positive example from WO2009068731, an intermediate fluid is used to vaporize LNG.

Method or means for heating fluid, the heat being recovered for later reuse.

In this positive example from WO2007019946, LNG is vaporized, and the cold energy used to liquefy oxygen.

Method or means for heating fluid, the heat being generated by solar energy.

Method or means for heating fluid, the heat being generated by burning a combustible.

In this positive example from WO2009032683, vaporizing of LNG occurs by using a submerged combustion vaporizer.

Method or means for heating fluid, the heat being generated by radiation from e.g. chemical processes.

Method or means for cooling fluid transferred.

Method or means for cooling fluid, the cooling effect being obtained by a using the same fluid as the fluid transferred out of or into a pressure vessel.

In this positive example from WO2005045337, the gaseous and the liquid phase of the fluid exchange heat in an external heat exchanger, the one being heated, the other cooled.

Method or means for cooling fluid, the cooling effect being obtained from another fluid than the fluid transferred out of or into a pressure.

In this positive example from EP1790904, hydrogen is cooled by nitrogen.

Method or means for cooling fluid, the cooling effect being obtained from air.

In this positive example from US2005284154, hot nitrogen gas is cooled by air.

Method or means for cooling fluid, the cooling effect being obtained from air in a forced circulation, e.g. by using a ventilator.

In this positive example from EP2110596, the hydrogen storage tank is cooled by a fan.

Method or means for cooling fluid, the cooling effect being obtained from water

In this positive example from US2009114290, gaseous CO₂ is condensed und thus cooled by using water.

Method or means for cooling fluid, the cooling effect being obtained from seawater.

In this positive example from US2720082, seawater is used to cool the liquefied gas of the storage tanks.

Method or means for cooling fluid, the cooling effect being obtained from a cryocooler, which uses e.g. helium or another fluid to generate cryogenic temperature.

In this positive example from US2005204752, a helium cryocooler is disclosed.

Method or means for cooling fluid, the cooing effect being obtained from another fluid that circulates in a closed loop.

In this positive example from WO2005071333, LNG boil-off gas is cooled in a closed-loop refrigeration system.

Method or means for cooling fluid, the cooling effect being obtained from expansion of the fluid.

Method or means for cooling fluid, the cooling effect being obtained from expansion of the fluid, the Joule-Thompson effect being mentioned or clearly implicit like when using a throttle.

Joule-Thompson formula:

The Joule-Thompson effect can either be cooling or heating, depending on the inversion temperature.

Method or means for cooling fluid, the cooling effect being obtained from expansion in a turbine.

In this positive example from WO2007028221, nitrogen is expanded in a turbine.

Method or means for cooling fluid, the cooling potential being recovered for later reuse.

Thermal exchange with the fluid, including heating and cooling, the thermal exchange taking place at particular locations.

Simple heat loss though vessel wall, without any particular device is not classified in this group or its sub-groups.

Thermal exchange with the fluid, the exchange taking place in or on the pressure vessel.

In this positive example form EP1167862, the heating device is mounted in or on the vessel.

Thermal exchange located in the gas phase of the fluid in the pressure vessel.

In this positive example from DE19720451, a heater is mounted in the gas phase.

Thermal exchange located in the liquid phase of the fluid in the pressure vessel.

In this positive example from DE19544593, a heating exchange device is located in the liquid phase.

Thermal exchange with the fluid in the pressure vessel, the thermal exchange device being in contact with the vessel wall.

Thermal exchange with the fluid in the pressure vessel, the thermal exchange device being located inside the vessel.

In this positive example from EP2103863, the heat exchange device is distributed all over the spherical inner wall surface.

Thermal exchange with the fluid in the pressure vessel, the thermal exchange device being integrated in the wall of the vessel.

In this positive example from WO9612521, the heat exchange device is mounted inside the wall of the vessel.

Thermal exchange with the fluid in the pressure vessel, the thermal exchange device not being in contact with the vessel.

In this positive example from US2002124575, the heat source is located below the vessel.

Thermal exchange with the fluid in the pressure vessel, the thermal exchange device being in form of a dismountable jacket.

In this positive example from FR2897413, the jacket covers the upper part of the vessel.

Thermal exchange with the fluid, including heating or cooling, the thermal exchange taking place at a location remote from the pressure vessel.

Thermal exchange with the fluid, the thermal exchange taking place on pipes.

In this positive example from DE102005049252, the pipe is heated.

Thermal exchange with the fluid, the thermal exchange being vaporization and taking place in a vaporizer.

In this positive example from US6598408, LNG is vaporized in a vaporizer.

In this positive example from WO03012277, the vaporizer is a compact unit.

Thermal exchange with the fluid, the thermal exchange taking place in a submerged a heat exchanger.

In this positive example from US2006288711, seawater vaporizes the LNG.

In this negative example from WO2004081441, there is no heat exchanger, but direct heat exchange between seawater and vessel.

Thermal exchange with the fluid, the thermal exchange process being supported by fins or rips.

In this positive example from US4598554, fins surround an vaporizer.

Fins or rips to improve strength of the structure without evidence that they increase heat transfer, are not classified here.

Method for filling or emptying pressure vessels.

In this negative example from DE748096, a particular alignment of vessels is disclosed (arrangement in series). This does not allow a conclusion how the filling or emptying takes place.

When the valve of a pressurized vessel is opened, fluid flows by pressure difference out of the vessel. This standard emptying of a pressure vessel is not classified, unless additional features make the method more specific.

A particular arrangement of vessels, like a serial one, or an arrangement in parallel, is not sufficient to classify here: the way of filling or emptying must be detailed.

Method for filling or emptying pressure vessels, the method comprising the filling or emptying of one vessel after another, instead of several vessels at the same time.

In this positive example from FR2874247, vessels are filled one by one.

In this negative example from US2006150640, salt caverns empty simultaneously.

Method for filling or emptying pressure vessels, the method comprising details about a switch-over from a first vessel or group of vessels, to a second vessel or group of vessels, once the filling or emptying of the first vessel or group of vessels is achieved.

In this positive example from FR2857728, a change-over from an emptied vessel to a spare vessel is described.

Method for filling a pressure vessel with gas by pressure cascade, i.e. from a group of pressure vessels at a different pressure levels each, the filling starting from the vessel at the lowest pressure and ending with the vessel at the highest pressure, so as to systematically obtain gas transfer by pressure difference, with the lowest pressure drop possible.

In this positive example from US2009229701, the filling is of cascade type.

Method for emptying a pressure vessel or pipes, that includes a step of purging, i.e. washing out residual gas by an inert gas

In this positive example from EP0916891, inert gas replaces residual gas.