Particular elements of heat exchangers; details of heat transfer devices; means for modifying heat transfer; control arrangements for heat exchangers.

Tubular elements; assemblies of tubular elements,e.g. particular shape, construction, geometry of individual tubular element, e.g. multiple wall conduits, tubes with variable shape.

Tubular elements of cross-section which is non circular, e.g. flat tubes, flat multichannel tubes.

Tubular elements of cross-section which is polygonal, e.g. square, rectangular.

Tubular elements which are crimped or corrugated in cross-section.

Tubular elements which are crimped or corrugated in longitudinal section.

Means for increasing heat transfer area, e.g. fins, ribs.

The fins are either outside the tubular elements: F28F 1/12 or inside the tubular elements: F28F 1/40. The subgroup F28F 1/42 covers fins being both inside and outside the elements.

Outside fins can either extend longitudinally: F28F 1/14, or laterally: F28F 1/24 or obliquely: F28F 1/34, relative to the axis of the tubular elements..

Longitudinal fins can be integral with the elements, e.g. extruded as unitary element,: F28F 1/16 or can be attachable to the element (removable): F28F 1/20, or can have portions which are common to several tubular elements: F28F 1/22.

Transversal fins can be integral with the elements,: F28F 1/26 or can be attachable to the element (removable): F28F 1/30, or can have portions which are common to several tubular elements: F28F 1/32.

Oblique fins can be in the form of helically wound fins or wire spirals: F28F 1/36.

Corrugated fins are classified in F28F 1/12.

Tubular elements which made from finned sections are classified in F28F 1/18 or F28F 1/28.

Staggered fins to form tortuous passages are in F28F 1/38.

Plate-like or laminated elements; assemblies of plate-like or laminated elements,e.g. particular shape, construction, geometry of individual plate-like or laminated element, e.g. arrangements for preventing direct contact between different heat-exchange media.

Heat exchangers formed by stacked plates permanently fixed together (not capable of being taken apart) are normally classified only in F28F 9/00 and not in F28F 3/08.

The subgroup F28F 3/02 covers elements or assemblies thereof with means for increasing heat-transfer area, e.g. with fins, wires, pins, corrugated plates.

The subgroup F28F 3/04 covers means which are integral with the plate-like or laminated element, e.g. in the form of local deformations of the elements, e.g. dimples, corrugations, or in the form of ribs.

The subgroup F28F 3/06 covers means which are attachable to the elements

(removable).

The subgroup F28F 3/08 covers elements constructed for building-up into stacks, e.g. capable of being taken apart, stacked plates with openings forming tubular heat-exchange passages.

The subgroup F28F 3/10 covers sealing means, e.g. gaskets at plate margins.

The subgroup F28F 3/12 covers elements constructed in the shape of a hollow panel, e.g. with channels, e.g. cold plate. Panels manufactured by inflation (roll-bonding, hydro-forming) are classified in F28F 3/14.

Particular type of moving elements, e.g. rotary drums or rollers (F28F 5/02), hollow impellers (F28F 5/04), hollow screw conveyor s (F28F 5/06).

Elements not covered by group F28F 1/00, F28F 3/00 or F28F 5/00, e.g. particular heat-exchange elements not in the form of tubular or plate-like elements.

Particular construction of casings or shells; particular frame elements, e.g. side plates for radiator cores; auxiliary members within casings, e.g. filling means, sealing means.

Auxiliary supports for elements

Supports for tubes or tube-assemblies, e.g. formed by plates, by slats, by tie-rods, by strips, by wires.

Header boxes (manifold, tank), end plates, e.g. header boxes with inner space divided by partitions or baffles; arrangements for fastening header box or end plate with casing; arrangements for fastening header (cover) with end plate; double end plates or hollow end plates; expansion chambers; header boxes with second heat exchanger disposed inside; floating elements; arrangements for connecting header boxes with flow lines; static flow control, e.g. heat exchange media distributing means.

Arrangements for connecting elements to header boxes or end plates, either by dismountable joints (F28F 9/06), or by permanent joints (F28F 9/16).

Dismountable joints can be: wedge-type connections, e.g. taper ferrule (F28F 9/08), or screw-type connection, e.g. gland, stuffing box (F28F 9/10), or flange-type connection, or made by force-joining, e.g. the elements are forced into the end plate, generally with a gasket (F28F 9/14).

Permanent joints means: using a working procedure for permanently deforming the elements or using bonding materials, e.g. adhesive, brazing or welding material for permanently joining the elements with the end plate or header box: the subgroup F28F 9/18 covers permanent joint by welding.

Arrangement of heat reflectors, e.g. protective walls inside casings.

Arrangement of guide plates inside casing, e.g. longitudinal, transversal or oblique baffles for guiding the heat exchange medium flowing inside the casing

Arrangements for promoting turbulent flow inside casing

Arrangements for connection different heat-exchange sections, e.g. elbows, connecting sleeves, nipples.

Devices or processes for repairing damaged heat exchange conduits

F28F 11/02: using obturating elements, e.g. washers, plugs

Means for optimizing heat transfer (increasing heat transfer), other than fins; Heat insulating means (decreasing heat transfer); e.g. thermal joints, use of particular conductive materials, thermal barriers, use of permeable mass, perforated or porous materials.

Increasing heat transfer by using means for increasing heat transfer area, e.g. fins: F28F 1/10, F28F 3/02

The following classification applies depending on the means for modifying heat transfer

F28F 13/02: by influencing fluid boundary

F28F 13/04: by preventing the formation of continuous films of condensate on heat-exchange surface, e.g. by promoting droplet formation (enhancing dropwise condensation)

F28F 13/06: by affecting the pattern of flow of the heat-exchange media, e.g. with inserts, deflectors, vortex generators.

F28F 13/08: by varying the cross-section of the flow channels

F28F 13/10: by imparting a pulsating motion to the flow, e.g. by sonic vibration

F28F 13/12: by creating turbulance, e.g. by stirring, by increasing the force of circulation

F28F 13/14: by endowing the walls of conduits with zones of different degrees of conduction of heat, e.g. heat conductive elements having heat insulating portions.

F28F 13/16: by applying an electrostatic field to the body of heat-exchange medium, e.g. enhancing heat transfer by electro hydrodynamic effects

F28F 13/18: by applying coatings, e.g. radiation-absorbing, radiation-reflecting, hydrophilic coatings, hydrophobic coatings, conductive coatings; porous coatings; by surface treatment, e.g. polishing, obtaining rough surfaces; heat exchange surfaces having microstructures, e.g. nucleation sites for enhancing nucleate boiling.

Means for draining water from heat exchangers, e.g. means for draining condensates from evaporators

Means for preventing corrosion, abrasion, erosion, damages in heat exchangers, e.g. by using inserts or attachments, by using protective electric currents; preventing deposits of ice, means for preventing freezing of heat exchange media; by using scrapers

Depending on the preventing means, the following classification applies:

F28F 19/01 by using means for separating solid materials from heat-exchange fluid, e.g. filters

F28F 19/02 by using coatings

F28F 19/04 plastic coatings

F28F 19/06 metallic coatings

Heat exchanging elements made by particular materials, e.g. glass.

Depending on the material, the following classification applies:

F28F 21/02: carbon, e.g. graphite

F28F 21/04: ceramic e.g. alumina, beryllia, zirconia carbide, boride, nitride, silicide; concrete; natural stone.

F28F 21/06: plastics, e.g. resins, polymeric materials, reinforced plastics.

F28F 21/08: metal, e.g. steel or ferrous alloys, stainless steel, aluminium or aluminium alloys, copper or copper alloys, titanium, nickel

Particular intermediate heat exchange materials

Arrangements for distributing, circulation or accumulating liquid

Distributing or accumulator troughs

Spray nozzles

Splashing boards or grids, e.g. for converting liquid sprays into liquid films; Elements or beds for increasing the area of the contact surface, e.g. in the form of spaced elongated bars, laths, horizontal grids, vertical or inclined sheets

Gas or vapour feeding

Ducts; Guide vanes

Controlling, monitoring heat exchangers, e.g. temperature control, pressure control, flow control, heat transfer control; Safety means.

The feature "controlling" means influencing a variable in any way e.g. changing its value, maintaining it constant, limiting its range of variation; "regulating" means maintaining a variable automatically at a desired value or within a desired range of values. The desired value may be fixed, manually varied or may vary with time according to a predetermined "programme". Regulation is a form of control.

Controlling the distribution of heat exchange media between different channels, e.g. flow control means in heat exchangers, e.g. valves