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 [Search a list of Patent Appplications for class 494]   CLASS 494,IMPERFORATE BOWL: CENTRIFUGAL SEPARATORS
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SECTION I - CLASS DEFINITION

Apparatus and process, not provided for elsewhere, for the breaking up or subdividing of material, which material comprises a mixture of fluids or fluent substances, into two or more components by utilizing a rotatable, receptacle-like member having a generally solid wall, and commonly termed a bowl, for subjecting the material to centrifugal force.

(1) Note. When the material is subjected to centrifugal force, the usual tendency is for the heavier component(s) (e.g., the "heavies") to move outwardly from the axis of rotation of the member and the lighter component(s) (e.g., the "lights") to move inwardly toward the axis. When plural heavier components of more than one density are present in the material, the outward movement ordinarily results in stratification, with the most dense component forming the layer nearest the wall, and so forth. When the heavier component, or one or more of a plurality thereof, is particulate in nature, the resulting layer, or layers, tends to be more or less solid.
(2) Note. Most frequently, the member is capable of receiving and holding the material while at rest, and thus is truly a receptacle; in some instances (e.g., a member in the form of a open-ended cylinder), however, it can receive and hold material only when in its operating (i.e., rotating) mode.
(3) Note. The use of the phrase "generally solid" to describe the wall of the member is not intended to infer that the wall behaves as anything other than an imperforate surface insofar as the separating function is concerned; rather, the purpose of the qualifying word is to acknowledge that there sometimes are one or more openings (e.g., discharge apertures) in the wall which serve a nonseparating function. See also Subclass References to the Current Class, below.

SECTION II - LINES WITH OTHER CLASSES AND WITHIN THIS CLASS

A centrifugal extractor, per se, for treating textiles is not in Class 494 if of the imperforate bowl type, inasmuch as the mixture involved is not one which this class (494) provides for. (See References to Other Classes, below.) If the extractor is perforate in nature, it may be proper for Class 210 (e.g., subclasses 360.1+).

LINE WITH CLASS 196 AND WITH CLASS 208

While the treating of a nominally mentioned oil by merely subjecting it to the action of an imperforate bowl, centrifugal separator does not go beyond the scope of this class (494), the apparatus of Class 196 and the processes of Class 208, in References to Other Classes, below, involve more; for example, (a) apparatus, or process, respectively, pertaining to an additional, chemical treatment of the oil, or (b) specific properties (e.g., the composition) of the oil or of one or more of its components.

SECTION III - SUBCLASS REFERENCES TO THE CURRENT CLASS

SEE OR SEARCH THIS CLASS, SUBCLASS:

43,(2) Note, for a discussion of the phrase "generally closed," and see the Class Definition, (3) Note, above.

SECTION IV - REFERENCES TO OTHER CLASSES

SEE OR SEARCH CLASS:

29, Metal Working,   subclass 279 for a hand tool which is particularly adpated for applying or removing component parts of a centrifugal separator.
34, Drying and Gas or Vapor Contact With Solids,   subclasses 312+ for a process of that class which involves subjecting the material being treated to centrifugal force, and subclasses 58+ for apparatus which utilizes centrifugal force.
57, Textiles: Spinning, Twisting, and Twining,   subclasses 76+ .
68, Textiles: Fluid Treating Apparatus,   subclasses 23+ for a machine of that class which is combined with a liquid extractor and wherein the extractor is centrifugal in nature. A centrifugal extractor, per se, for treating textiles also is in that area (23+) if of the imperforate bowl type, inasmuch as the mixture involved is not one which this class (494) provides for. For an extractor that is perforate in nature, see Lines With Other Classes and Within This Class, above.
73, Measuring and Testing,   subclasses 535+ .
95, Gas Separation: Processes,   for processes involving steps resulting in separation of a gas from a fluid mixture comprising (a) a gas and solid or liquid particles entrained therein, (b) a liquid and gas entrained therein, or (c) a plurality of gases. However, gas separation processes that use an imperforate bowl, centrifugal separator are proper for Class 494.
96, Gas Separation: Apparatus,   for apparatus used in separation of a gas from a fluid mixture comprising (a) a gas and solid or liquid particles entrained therein, (b) a liquid and gas entrained therein, or (c) a plurality of gases. However, gas separation apparatus that is an imperforate bowl, centrifugal separator is proper for Class 494.
99, Foods and Beverages: Apparatus,   subclasses 452+ for apparatus of that class utilized for the mechanical, fluid or heat treatment of dairy food. Prominent in this class (494), however, is the separating of raw milk into one or more heavier components (e.g., skim milk) and one or more lighter components (e.g., cream).
118, Coating Apparatus,   subclasses 52+ .
124, Mechanical Guns and Projectors,   subclasses 4+ .
127, Sugar, Starch, and Carbohydrates,   subclass 19 for apparatus of that class for treating sacchariferous material involving the treatment of sugar crystals and wherein the apparatus includes means for applying centrifugal force, and subclass 56 for a process of that class directed to the separation, in a mechanical manner, of impurities from a sugar solution and wherein centrifugal force is relied upon to separate impurities from a sugar solution which is of a different specific gravity than the impurities.
134, Cleaning and Liquid Contact With Solids,   subclass 17 and 33.
156, Adhesive Bonding and Miscellaneous Chemical Manufacture,   subclass 74 .
159, Concentrating Evaporators,   subclasses 6.1+ .
162, Paper Making and Fiber Liberation,   subclass 384 .
164, Metal Founding,   subclasses 114+ , 175, and 286+.
184, Lubrication,   subclasses 6.24+ for a system of lubrication which is provided with means for treating the lubricant of the system and wherein the treatment is in the nature of purification, which may involve a separating operation.
184, Lubrication,   subclass 43 , 70, and 77.
196, Mineral Oils: Apparatus,   subclass 14.5 for apparatus of that class for separating wax from a petroleum oil for either recovering the wax or purifying the oil, and subclasses 46+ for apparatus adapted for separating either impurities or nonmineral oil components from mineral oil. (See Lines With Other Classes and Within This Class, for the line with Class 494.)
200, Electricity: Circuit Makers and Breakers,   subclass 80 .
208, Mineral Oils: Processes and Products,   appropriate subclasses, for a process of that class for the recovery or treatment (including separating) of naturally occurring mineral oil, which process results in the production of a purified or modified oil or of coke. (See Lines With Other Classes and Within This Classabove, for the line with Class 494.)
209, Classifying, Separating, and Assorting Solids,   appropriate subclasses, for process and apparatus for separating solid materials and assorting or segregating them in grades or classes according to physical characteristics. The relationship of Class 209 with this class (494) is explained in (6) Note of the class definition of Class 209, which reads as follows: "This class does not include apparatus or methods which involve the use of bowls or receptacles rotating at speed high enough to develop sufficient centrifugal force to separate one class of solids from others unless there is "amalgamation" involved, in which case such apparatus or methods are classifiable in subclass 60 and 199 of this class. Cases not falling within the exception noted are classifiable in Class 494, Imperforate Bowl: Centrifugal Separators. This class, however, does include some borderline cases where it is not clear that the separation of the classes of solids is wholly dependent upon centrifugal force generated by high speed rotation of the receptacle."
210, Liquid Purification or Separation,   subclasses 360.1+ for apparatus of that class wherein the constituents of a mixture are separated by passing the mixture through a medium having openings (i.e., a filter) and wherein the medium is adapted for rapid movement about an axis of rotation, subclasses 781+ for a process of that class for separating one constituent of either a liquid-liquid or a liquid-solid mixture and wherein motion, relative to its support or housing, is imparted to the filter medium and further wherein the mixture is caused to pass through the medium by centrifugal force, and subclasses 787+ for a process for separating one constituent of either a liquid-liquid or a liquid-solid mixture and wherein centrifugal force is developed by cyclonic movement of the mixture (but not involving movement of the filter); also, see Lines With Other Classes and Within This Class, above.
239, Fluid Sprinkling, Spraying, and Diffusing,   subclass 7 .
241, Solid Material Comminution or Disintegration,   appropriate subclasses, for process or apparatus of that class when combined with process or apparatus for the separation of material. The relationship of that class (241) to the material separating classes is explained in Lines With Other Classes and Within This Class, in the class definition thereof, which reads, in part, as follows: "Class 241 is superior to the material separation classes and, therefore, provides for processes and apparatus in which comminution is combined with steps or means to separate the material into classes according to the physical characteristics of its components, before, during, or after the comminuting operation. See subclasses 9+ , 24 and 68+ or, if the separation involves applying a fluid to the material, subclasses 19, 20 and 38+."
264, Plastic and Nonmetallic Article Shaping or Treating: Processes,   subclass 8 , 114, 270, and 311.
266, Metallurgical Apparatus,   subclass 204 and 227+.
277, Seal for a Joint or Juncture,   subclasses 427+ and 433.
366, Agitating,   subclass 263 .
415, Rotary Kinetic Fluid Motors or Pumps,   subclasses 13+ , 25, and 89.
422, Chemical Apparatus and Process Disinfecting, Deodorizing, Preserving, or Sterilizing,   subclass 72 for apparatus of that class comprising means for analyzing a liquid or solid sample and wherein the means includes a centrifuge.
427, Coating Processes,   subclass 240 .
451, Abrading,   subclasses 465+ and 506.

SECTION V - GLOSSARY

BOWL

A receptacle-like member having generally-imperforate sidewalls and constituting that portion of a SEPARATOR within which the subdividing of material into two or more components takes place, or, at least, commences. Ordinarily considered as part of the member are such devices or structure as are either affixed thereto or integral therewith. The art term, rotor, is sometimes used to mean approximately the same as BOWL. (See the Class Definition, (2) Note and (3) Note, above, and see Subclass References to the Current Class, above, for a discussion of the phrase "generally closed.")

SEPARATOR

The combination of a BOWL plus such other devices or structure not clearly a part of the BOWL as are necessary to constitute apparatus of the kind capable of subdividing material by subjecting it to centrifugal force within the BOWL. The art terms, centrifuge and centrifugal, are sometimes used to mean approximately the same as SEPARATOR.

SUBCLASSES

[List of Patents for class 494 subclass 1]    1WITH CONDITION RESPONSIVE MEANS:
 This subclass is indented under the class definition.  Apparatus provided with means which reacts to a condition, or a change of condition, of the separator, or the environment of the separator, or the material entering, within, or departing from the separator, the reaction of the means serving as a response to the condition or the change therein.
(1) Note. The means may range from a relatively sophisticated system for controlling the operation of the separator, which system may include a means to sense a condition and a means to respond to the information sensed, to a mere element of the separator, which element, by virtue of, for example, (a) its design or (b) the material of which it is formed inherently reacts to a condition to which it is exposed, subjected, etc.

SEE OR SEARCH THIS CLASS, SUBCLASS:

11,for a separator provided with cyclic or time control means.

SEE OR SEARCH CLASS:

210, Liquid Purification or Separation,   subclasses 97+ for apparatus of that class which is responsive to flow, fluid pressure, or material level, and subclasses 143+ for apparatus which has automatic control.
  
[List of Patents for class 494 subclass 2]    2For controlling outlet valve:
 This subclass is indented under subclass 1.  Apparatus wherein the means is one which serves to operate, or to regulate the operation of, a valve which controls an outlet of the separator, usually located on the receptacle-like member.
  
[List of Patents for class 494 subclass 3]    3In response to location of inner boundary of heavy component:
 This subclass is indented under subclass 2.  Apparatus wherein the condition to which the means reacts is the locus defining the innermost extent to which stratification of the heavier component of the material has progressed within the member.
(1) Note. While the inner boundary of one component usually coincides with the outer boundary of another component, and therefore represents their interface, the inner boundary of the heavier component sometimes lends itself to being located more precisely.
  
[List of Patents for class 494 subclass 4]    4In response to centrifugal force:
 This subclass is indented under subclass 2.  Apparatus wherein the condition to which the means reacts is the effect of the force imposed upon it by the rotation of the member.
(1) Note. The means may be no more than a normally-closed or a normally-open valve which is caused by the force to which is subjected to change to its opposite mode.
  
[List of Patents for class 494 subclass 5]    5For controlling inlet valve:
 This subclass is indented under subclass 1.  Apparatus wherein the means is one which serves to operate, or to regulate operation of, a valve which controls an inlet of the separator, which valve occasionally is located on the receptacle-like member.
(1) Note. Included herein is art wherein the condition to which the means reacts is the weight of the bowl or its contents.
  
[List of Patents for class 494 subclass 6]    6In response to level of liquid-type material in bowl or in reservoir for supplying bowl:
 This subclass is indented under subclass 5.  Apparatus wherein the condition to which the means reacts is the location of the surface of a quantity of material to be, or being, separated, which surface is that formed by the material when it is in either the receptacle-like member or in a container which furnishes (e.g., meters) it to the member, and which material is in the nature of either a liquid or a slurry.
  
[List of Patents for class 494 subclass 7]    7For controlling drive of (a) bowl or (b) driven means within bowl:
 This subclass is indented under subclass 1.  Apparatus wherein the means is one which serves to operate, or to regulate the operation of, a motor, transmission or other device which drives either (a) the receptacle-like member or (b) a conveyor, an agitator or other driven device located in the member.
(1) Note. The function and operation of a driven means within the bowl is discussed at length in (2) Note and (3) Note of subclass 50 below.
(2) Note. Included herein is art wherein the condition to which the means reacts is an excessive vibration on the part of the bowl.

SEE OR SEARCH THIS CLASS, SUBCLASS:

50,as explained in the reference thereto appearing in (1) Note above.
  
[List of Patents for class 494 subclass 8]    8In response to load imposed upon driven means:
 This subclass is indented under subclass 7.  Apparatus wherein the condition to which the means reacts is the effort (e.g., the torque) which the conveyor, agitator or other driven device in the member must develop to move the material which it engages therein.
  
[List of Patents for class 494 subclass 9]    9In response to speed of bowl or rotarily-driven means therewithin:
 This subclass is indented under subclass 7.  Apparatus wherein the condition to which the means reacts is the velocity, usually expressed in revolutions per minute, at which either the member, or a device therein which is driven rotatably, turns, or a change in that value.
(1) Note. Included herein is art wherein the condition to which the means reacts is the difference between the speed of the bowl and that of the rotarily-driven means.
  
[List of Patents for class 494 subclass 10]    10WITH MEANS FOR INDICATING, INSPECTING, MEASURING, SIGNALING, OR TESTING:
 This subclass is indented under the class definition.  Apparatus provided with means for carrying out, or for facilitating the carrying out of, those purposes ordinarily associated with the functions of indicating, inspecting, measuring, signaling, or testing, which means might comprise, but are not limited to, a tachometer, a viewing port, a scale, an audible or visual alarm, or a viscosimeter, respectively.
(1) Note. Obviously, the functions may not be mutually exclusively insofar as the means for carrying them out are concerned; hence, the fact that it may not be possible to restrict the association of a particular means to only one, specific function is immaterial.

SEE OR SEARCH CLASS:

96, Gas Separation: Apparatus,   subclasses 414+ for gas separation apparatus having inspection means and subclasses 417+ for gas separation apparatus having signals, indicators, measuring, or testing means.
73, Measuring and Testing,   appropriate subclasses, for measuring or testing means peculiar to that class.
210, Liquid Purification or Separation,   subclasses 85+ for apparatus peculiar to that class which is provided with alarm, indicator, register, recorder, signal or inspection means.
324, Electricity: Measuring and Testing,   appropriate subclasses, for measuring and testing means peculiar to that class.
  
[List of Patents for class 494 subclass 11]    11WITH CYCLIC OR TIME CONTROL MEANS:
 This subclass is indented under the class definition.  Apparatus provided with means for causing the separator, or a component thereof, to operate in accordance with (a) a predetermined sequence of events (e.g., program control by a cam), or (b) the progression of time (e.g., the length of time to be allotted to each of one or more phases of the separating function) as determined by a device having at least the capability of establishing a time interval (e.g., a timer) and possibly having also the capability of relating the time interval to the time of day (e.g., a clock-timer).
(1) Note. The term "automatic" frequently is utilized in describing the operation of the art of this subclass.
(2) Note. The reference to a "cam" in (a) above is not intended to infer that a cam may not be found elsewhere in the class; see, for example, subclasses 47+ below, where the "other movement" may result from the use of a cam.

SEE OR SEARCH THIS CLASS, SUBCLASS:

47+,as explained in the reference thereto appearing in (2) Note above.

SEE OR SEARCH CLASS:

96, Gas Separation: Apparatus,   subclasses 424+ for gas separation apparatus having timing or changeable programming means.
210, Liquid Purification or Separation,   subclasses 138+ for apparatus of that class which is provided with time control.
  
[List of Patents for class 494 subclass 12]    12INCLUDING MEANS OR STRUCTURE FOR PROMOTING SAFETY:
 This subclass is indented under the class definition.  Apparatus which includes a provision in the nature of a device or element, or merely a structural feature, which is indicated as being intended to reduce or eliminate one or more hazards of a kind associated with the separator, especially during its operation.
(1) Note. If mere strength of the bowl wall, for example, is involved, and there is no express statement relating that property to safety, classification in subclass 81 below, rather than here (12), is proper.

SEE OR SEARCH THIS CLASS, SUBCLASS:

81,as explained in the reference thereto appearing in (1) Note above.
  
[List of Patents for class 494 subclass 13]    13WITH MEANS FOR EXCHANGING HEAT:
 This subclass is indented under the class definition.  Apparatus provided with means for changing the heat content of either the material or the separator.

SEE OR SEARCH CLASS:

165, Heat Exchange,   appropriate subclasses, for process and apparatus for transferring heat from one material to another.
210, Liquid Purification or Separation,   subclasses 175+ for apparatus of that class provided with a heater or a heat exchanger.
219, Electric Heating,   subclass 389 for a heating device of that class which is associated with a container or an enclosure for material to be heated and wherein the container or enclosure is adapted to be rotated about an axis.
  
[List of Patents for class 494 subclass 14]    14Comprising or including means for cooling:
 This subclass is indented under subclass 13.  Apparatus wherein the means for changing the heat content comprises or includes a device, fluid or system for reducing the heat content.

SEE OR SEARCH CLASS:

62, Refrigeration,   appropriate subclasses, for process and apparatus peculiar to removing heat from a substance, or the product of such removal, or the handling of the latter as a stored product.
  
[List of Patents for class 494 subclass 15]    15WITH MEANS FOR LUBRICATING:
 This subclass is indented under the class definition.  Apparatus provided with means for furnishing antifriction material to one or more regions thereof.
(1) Note. The material ordinarily is of a fluid or a fluent nature; e.g., oil, grease, graphite.

SEE OR SEARCH CLASS:

184, Lubrication,   appropriate subclasses, for lubrication and lubricators, generally.
  
[List of Patents for class 494 subclass 16]    16INCLUDING PLURALITY OF MINIATURE BOWLS (E.G., TEST TUBES) DISTRIBUTED ABOUT A ROTATABLE CARRIER AND READILY REMOVABLE THEREFROM:
 This subclass is indented under the class definition.  Apparatus which includes two or more, extremely small, receptacle-like members for receiving the mixture and holding it during separation, and a revolving support for holding, at intervals spaced therearound, the members and further wherein the members are retained by the support in such a manner that they may be more or less easily disengaged therefrom.
(1) Note. The members most frequently comprise test tubes into which may be placed blood samples for separation into, for example, red cells and plasma.
(2) Note. The spacing of the containers on the support is such that the assembly will remain balanced.
(3) Note. Including in this and the indented subclasses is art directed to only a subcombination of the revolving support and/or the receptacle-like member.
(4) Note. In view of the uniqueness of the art of this area (16+), cross-referencing between this area and the other principal areas of the class is, for the most part, neither appropriate nor beneficial.

SEE OR SEARCH CLASS:

210, Liquid Purification or Separation,   subclass 782 for a process of that class for separating one constituent of either a liquid-liquid or a liquid-solid mixture and wherein motion, relative to its support or housing, is imparted to the filter medium and further wherein the mixture is caused to pass through the medium by centrifugal force and additionally wherein the mixture comprises blood.
422, Chemical Apparatus and Process Disinfecting, Deodorizing, Preserving, or Sterilizing,   subclasses 44+ for a device of that class for treating transfusible blood.
424, Drug, Bio-Affecting and Body Treating Compositions,   subclasses 529+ for a composition of that class wherein the active ingredient is an animal tissue extract of undetermined constitution and further wherein the composition contains either a blood extract or a structurally undetermined component obtained from blood.
604, Surgery,   subclass 507 for methods of introducing therapeutic material into or removing it from the vasculature system.
  
[List of Patents for class 494 subclass 17]    17And means for introducing either material or auxiliary fluid into bowls:
 This subclass is indented under subclass 16.  Apparatus which includes also means for feeding either (a) the material which is to be separated or (b) one or more fluids, which fluid or fluids are not initially a part of the material to be separated, to the members.
(1) Note. While not initially a component of the material supplied for separation, the fluid of this subclass sometimes becomes an indistinguishable part of either the material or a separated component thereof.
(2) Note. Typical of the art of this subclass is the supplying of a liquid for "washing" a sample of blood.
  
[List of Patents for class 494 subclass 18]    18Including conduit of flexible umbilical cable type:
 This subclass is indented under subclass 17.  Apparatus which further includes a flaccid, tubular element for conducting the mixture or other fluid from a stationary supply, or supply connection, to or from the receptacles while they are rotating with the carrier.
(1) Note. The development and use of a conduit of this nature is generally considered to reduce certain maintenance and contamination problems inherent in the rotating seal which it eliminates.
  
[List of Patents for class 494 subclass 19]    19And means for rotating each bowl about own axis:
 This subclass is indented under subclass 16.  Apparatus which includes also means for imparting rotary movement, about its principle axis, to each of the members.
(1) Note. Here, the centrifugal force for causing separation of the mixture is developed in part by the revolving of the support and in part by the additional turning of each member about its own axis.
  
[List of Patents for class 494 subclass 20]    20Having bowls, or holders therefor, pivotably attached to carrier for tilting during rotation of carrier:
 This subclass is indented under subclass 16.  Apparatus wherein either each member, or each of a plurality of receivers provided with accommodations for one or more members, is joined to the support in a manner (e.g., pivoted at a locus above the center of gravity of the member or the receiver) whereby the lower portion of each member or receiver will swing, about a horizontal axis, outwardly and upwardly when acted upon by the centrifugal force developed by the revolving of the support.

SEE OR SEARCH THIS CLASS, SUBCLASS:

16,for related art but wherein, for example, (a) the outward and upward movement of the lower portion of the member is not in the nature of turning about an axis, or (b) each member is fixedly supported at a predetermined degree of tilt.
  
[List of Patents for class 494 subclass 21]    21Comprising flexible bowls embraced by pockets provided therefor in carrier:
 This subclass is indented under subclass 16.  Apparatus wherein the members are flaccid in nature and are held within cavities, compartments or the like located in the revolving support.
(1) Note. Prior to being filled with the mixture, the member of this subclass may be collapsed; i.e., flat. Upon filling, it assumes the shape of its cavity, thereby sometimes resembling a liner therefor. The confinement thus provided enables the member to withstand the centrifugal force to which it is subjected.
  
[List of Patents for class 494 subclass 22]    22INCLUDING INTRODUCTION OF DIFFERING-WEIGHT FLUIDS (E.G., LIQUIDS) FOR COUNTERCURRENT FLOW:
 This subclass is indented under the class definition.  Apparatus which includes supplying to the bowl two or more fluids, usually two liquids but sometimes a liquid and a gas, which differ in specific gravity and which difference enables radially outwardly movement of the heavier fluid to take place more or less simultaneously with radially inwardly movement of the lighter fluid.
(1) Note. A principle function of the opposing flow is to achieve intimate contact of one fluid with another, which fluids most frequently are two, immiscible or partly immiscible liquids, and which contact is sometimes described in terms of one fluid acting as a solvent upon the other.
(2) Note. The purpose of the intimate contact (occasionally described as "sliding surface contact") and subsequent separation sometimes is to promote a chemical reaction between the liquids, or, occasionally, it may be for transferring one or more components from one liquid to the other.
(3) Note. Separators of the countercurrent flow type are particularly useful in separating liquids whose specific gravities differ so slightly that separation in a conventional separator might prove impractical.
(4) Note. Separating apparatus of the kind peculiar to this subclass is sometimes identified as an "extractor" (where two liquids are involved) or an "evaporator" (where a liquid and a gas are involved).

SEE OR SEARCH CLASS:

210, Liquid Purification or Separation,   subclass 799 , for a process of that class for separating one constituent of a liquid-liquid mixture and wherein the liquids are immiscible.
422, Chemical Apparatus and Process Disinfecting, Deodorizing, Preserving, or Sterilizing,   subclasses 258+ for apparatus of that class having means for separating or dissolving a material constituent and wherein the means is of the liquid-liquid contact kind and further wherein the means includes a rotating chamber.
  
[List of Patents for class 494 subclass 23]    23WITH MEANS FOR FURNISHING AUXILIARY FLUID TO MATERIAL OR APPARATUS:
 This subclass is indented under the class definition.  Apparatus provided with means for introducing, or for facilitating the introduction of, one or more fluids, which fluid or fluids are not initially a part of the material intended to undergo separation, to the material or to one or more components or elements of the separator.
(1) Note. While not constituting a portion of the material as supplied for separation, the fluid of this subclass sometimes becomes an indistinguishable part of either that material or a separated component thereof.
(2) Note. Included in this and the indented subclasses, especially subclasses 27+ is the introducing of a fluid for a cleaning purpose.
(3) Note. Suction is not considered to be the introduction of a fluid within the concept of this and the indented subclasses; note, however, that suction for the purpose of reducing the pressure in a housing for a bowl is provided for in subclass 61 below.
(4) Note. The furnishing of a fluid for actuating a component (e.g., a valve) of the separator is included in this and the indented subclasses.

SEE OR SEARCH THIS CLASS, SUBCLASS:

13+,for a separator provided with means for exchanging heat, which means may involve a fluid in the nature of a medium of heat exchange.
15,for a separator provided with means for lubricating, which means may involve a fluid in the nature of a lubricant.
17,for a separator which includes a plurality of miniature bowls distributed about a rotatable carrier and readily removable therefrom and wherein means is provided for introducing either the material or an auxiliary fluid into the bowls.
61,as explained in the reference thereto appearing in (3) Note above.

SEE OR SEARCH CLASS:

96, Gas Separation: Apparatus,   subclasses 372+ for gas separation apparatus including inlet means for diverse gas or solid for gas treatment.
210, Liquid Purification or Separation,   subclasses 198.1+ for apparatus of that class provided with means to add treating material.
  
[List of Patents for class 494 subclass 24]    24Energy of fluid utilized for driving bowl:
 This subclass is indented under subclass 23.  Apparatus wherein the fluid is under pressure or otherwise possesses energy, and wherein that property of the fluid is used for imparting rotation to the member.
(1) Note. The fluid may serve only to enhance the rotation of a bowl which is provided also with driving means of a different nature.
(2) Note. Most commonly, a fixed or adjustable nozzle is utilized to direct the fluid against one or more regions of the member, which regions may be particularly adapted to receive and react to the force of the fluid.
  
[List of Patents for class 494 subclass 25]    25Gas other than air:
 This subclass is indented under subclass 23.  Apparatus wherein the fluid introduced is in the nature of a gas, and wherein the gas has a composition which serves to distinguish it from that gas commonly considered to constitute "air".
  
[List of Patents for class 494 subclass 26]    26Air at atmospheric, or greater, pressure:
 This subclass is indented under subclass 23.  Apparatus wherein the fluid introduced is air which is at either the pressure normal to the region in which the separator is located or a pressure which is elevated from that pressure.
(1) Note. See (3) Note of subclass 23 above.
(2) Note. Included in this subclass is a body of art which is concerned with counteracting the derogatory effect on the separating process caused by the movement of air within a housing provided for the bowl, which movement is created most frequently by the friction developed between the rotating bowl and the air surrounding it. The means making this particular art proper for this subclass usually comprises an inlet for admitting outside air to the housing, which latter air is utilized to at least partially overcome the undesired results (e.g., intermingling, or loss, of liquids which have been separated) of the movement of the air already in the housing.
(3) Note. As a sidelight to (2) Note., it can be observed that an aperture for admitting air, if located in a lower region of the housing, may serve also as an outlet for unwanted substances (e.g., liquids, foreign particles) which otherwise would accumulate there.

SEE OR SEARCH THIS CLASS, SUBCLASS:

60+,especially subclasses 60 and 63 for a separator which includes an exterior housing for the rotatable bowl, which subclasses include a collection of art that is concerned with the movement of only that air which already is in housing, as contrasted with the situation discussed in (2) Note above.
  
[List of Patents for class 494 subclass 27]    27Liquid:
 This subclass is indented under subclass 23.  Apparatus wherein the fluid introduced is in the nature of a liquid.
(1) Note. See the reference to this subclass (27) contained in (2) Note of subclass 23 above.

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23,as explained in the reference thereto appearing in (1) Note above.
  
[List of Patents for class 494 subclass 28]    28Moving radially inwardly toward axis of rotation of bowl:
 This subclass is indented under subclass 27.  Apparatus wherein the liquid flows from one or more regions removed from the axis about which the member turns (e.g., an inlet on the periphery of the member) in the direction of that axis.
(1) Note. The countercurrent flow provided for in subclass 22 above represents another provision for radially inwardly flow of fluid, but is to be distinguished from the subject matter of this subclass (28) on the basis that there (22) the flow is that of one of the two fluids which are essential to the separation, whereas here the radially inwardly flow is that of an auxiliary fluid (i.e., an auxiliary liquid).

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22,as explained in the reference thereto appearing in (1) Note above.
  
[List of Patents for class 494 subclass 29]    29Furnished at plural locations:
 This subclass is indented under subclass 27.  Apparatus wherein the liquid is introduced at more than one place.
(1) Note. Most commonly, the liquid is introduced into the member, and, most frequently, by utilizing plural conduits.
(2) Note. Two or more different liquids may be involved.
  
[List of Patents for class 494 subclass 30]    30Including one or more valves in incoming path:
 This subclass is indented under subclass 27.  Apparatus wherein at least one valve is provided for controlling the liquid which is enroute to the separator.
  
[List of Patents for class 494 subclass 31]    31INCLUDING PLURALITY OF SEPARATE AND DISTINCT BOWLS:
 This subclass is indented under the class definition.  Apparatus which includes two or more receptacle-like members, no one of which members is contained in whole or in part in any other member, and each of which members serves as the locus of a separating function.
(1) Note. The separating functions taking place in the members sometimes are identical; however, they are more likely to differ in, for example, the king or the phase or the degree of separation.
(2) Note. "Separate" is not intended to exclude an externally touching (e.g., a rolling contact) relationship between two or more of the members.

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16+,for a separator which includes a plurality of miniature bowls (e.g., test tubes) distributed about a rotatable carrier and readily removable therefrom.
44,for a separator wherein the rotatable bowl comprises a plurality of bowls which are partly or wholly within one another.

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55, Gas Separation,   subclasses 482+ for apparatus of that class including plural separators.
210, Liquid Purification or Separation,   subclasses 294+ for apparatus of that class including diverse, distinct separators, and subclasses 322+ for apparatus including plural, distinct separators.
  
[List of Patents for class 494 subclass 32]    32And means external of bowls for conducting material therebetween:
 This subclass is indented under subclass 31.  Apparatus which includes means (e.g., a conduit, surface, etc.) for enabling material to move from one member to another, which means is located, at least in part, outside of one or both of the members with which it is associated.
(1) Note. Included herein are instances wherein material moves back to a member which it occupied at an earlier stage of the separating function; e.g., "feedback".
  
[List of Patents for class 494 subclass 33]    33Having bowls equally spaced from a central axis of rotation for orbiting thereabout:
 This subclass is indented under subclass 31.  Apparatus wherein the members describe a common path as they turn about an axis from which each member is equidistantly removed.

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16+,as explained in the reference thereto appearing in subclass 31 above, and with the further observation that the bowls of that area (16+) are spaced from and turn about a central axis of rotation.
  
[List of Patents for class 494 subclass 34]    34Having bowls spaced along common axis of rotation:
 This subclass is indented under subclass 31.  Apparatus wherein the members occupy successive, but not overlapping, positions along the axis about which they turn.
(1) Note. While the driving means here typically is a shaft common to each of the members, concentric shafts are sometimes utilized.
  
[List of Patents for class 494 subclass 35]    35BOWLS AND MEANS EXTERNAL THEREOF FOR RECIRCULATING MATERIAL:
 This subclass is indented under the class definition.  Apparatus wherein a receptacle-like member is provided with means, located at least in part outside thereof, for conducting material away from the member and subsequently returning all or a part of that material to the member.
(1) Note. The material leaving and later returning to the member may constitute, for example, (a) material for which a higher degree of separation is desired than could be obtained by passing through the member once, or (b) material which was in excess of the separating capacity of the member upon the occasion of its initial entry thereinto, or (c) leakage which has been collected.
(2) Note. The outside means may include a driven device (e.g., a pump) for moving the material.
(3) Note. The means, while outside, at least in part, of the member, is not necessarily outside of any such structure as may be provided for enclosing the member.

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32,for a separator which includes a plurality of separate and distinct bowls and which also includes means external of the bowls for conducting material therebetween.

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55, Gas Separation,   subclasses 338+ for apparatus of that class provided with recycle means.
210, Liquid Purification on Separation,   subclasses 194+ for apparatus of that class involving recirculation.
  
[List of Patents for class 494 subclass 36]    36WITH MEANS FOR FILTERING:
 This subclass is indented under the class definition.  Apparatus provided with means for removing an undesired or unintended constituent (e.g., particles of a solid) from material which is enroute to, or within, or enroute from, a separator, and wherein the means is a medium of a porous or perforate nature which is placed in the flow path of the material and prevents the constituent from continuing to accompany the remainder of the material.
(1) Note. The means usually is in the nature of a screen, sieve, strainer, or the like (e.g., a fibrous batt).

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196, Mineral Oils: Apparatus,   subclass