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 [Search a list of Patent Appplications for class  23]   CLASS 23,CHEMISTRY: PHYSICAL PROCESSES
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SECTION I - CLASS DEFINITION

Processes for preparation or treatment of inorganic compounds and nonmetallic elements which involve only physical treatments not specifically provided for in some other class. See subclass 293.

SUBCLASSES

[List of Patents for class 23 subclass 293]    293PHYSICAL PROCESSES:
 This subclass is indented under the class definition.  Physical processes not more specifically provided for in other classes.
(1) Note. Patents containing both a claim to an inorganic compound or non-metallic element, and a claim to a physical process for this class, are classified in Class 423, Chemistry of Inorganic Compounds, and cross-referenced here.
(2) Note. The removal or addition of water of hydration or cystallization is considered a chemical reaction and not a physical process for this class. For such processes see the appropriate chemical class, e.g., 423, Chemistry of Inorganic Compounds, 260, Chemistry of Carbon Compounds, 585, Chemistry of Hydrocarbon Compounds, etc.
(3) Note. Processes for preserving chemicals and compositions are classified with the chemical or composition preserved and processes of packaging chemicals are classified in Class 53, Package Making, except when chemicals classifiable in Classes 260, Chemistry of Carbon Compounds, and 423, Chemistry of Inorganic Compounds, 585, Chemistry of Hydrocarbon Compounds, are stored by means of a chemical combination from which the chemicals may be subsequently released, when they are classified on the basis of the chemical combination so formed.

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34Drying and Gas or Vapor Contact With Solids,   for drying processes.
53Package Making,   appropriate subclasses for methods of and apparatus for encompassing or encasing goods or materials with a separate cover or band which serves as means for identifying, protecting or unit handling the goods or materials. See (3) Note.
62Refrigeration,   subclasses 600+ for processes and apparatus specialized to the manufacture of a solidified or liquefied product from a gas by physical treatment only.
75Specialized Metallurgical Processes, Compositions for Use Therein, Consolidated Metal Powder Compositions, and Loose Metal Particulate Mixtures,   for processes provided for in that class which may include a physical process.
95Gas Separation: Processes,   for physical processes of gas separation and purification.
100Presses,   subclasses 35+ for processes for compacting material, not elsewhere provided for.
127Sugar, Starch, and Carbohydrates,   for processes of extracting and crystallizing sugar.
159Concentrating Evaporators,   for processes of concentrating solutions or suspensions of solids in liquids.
201Distillation: Processes, Thermolytic,   appropriate subclasses for a destructive distillation process.
203Distillation: Processes, Separatory,   appropriate subclasses for a separatory distillation process.
209Classifying, Separating, and Assorting Solids,   for processes of separating solids from solids.
210Liquid Purification or Separation,   subclasses 634+ , especially 643+ for processes of liquid purification including dialysis, and subclasses 800+ for processes for liquid separation by gravitational force.
241Solid Material Comminution or Disintegration,   appropriate subclass, for processes and apparatus involving comminution and see section 2 of the class definition of that class (241) for the line.
261Gas and Liquid Contact Apparatus,   for processes for contacting gases and liquids when for a purpose other than that of gas separation or purification.
264Plastic and Nonmetallic Article Shaping or Treating: Processes,   appropriate subclasses for processes involving shaping or molding of plastic materials, noting, for example, subclass 4 , pertaining to encapsulating of normally liquid material.
366Agitating,   for mixing or agitating processes.
422Chemical Apparatus and Process Disinfecting, Deodorizing, Preserving, or Sterilizing,   subclasses 243+ for physical type apparatus including apparatus used in carrying out come processes of this class (23).
426Food or Edible Material: Processes, Compositions, and Products,   appropriate subclasses for physical processes involving foods.
432Heating,   subclasses 1+ for a material heating process of general utility.
494Imperforate Bowl: Centrifugal Separators,   appropriate subclasses for apparatus and process for breaking up a mixture of fluids or fluent substances into two or more components by centrifuging within a generally solid-walled, receptacle-like member.
  
[List of Patents for class 23 subclass 294]    294Sublimation:
 This subclass is indented under subclass 293.  Processes directed to or including sublimation as a significant step.

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266Metallurgical Apparatus,   subclasses 144+ for metallurgical furnaces with fume arresters.
  
[List of Patents for class 23 subclass 295]    295Crystallization:
 This subclass is indented under subclass 293.  Processes directed to or including crystallization as a significant step.

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29Metal Working,   subclass 25.35 for processes of manufacturing piezo-electric crystal devices which include crystallizing and additional manufacturing operations.
62Refrigeration,   for processes of crystallization including a step of refrigeration, especially see subclasses 66+ and subclasses 532+.
65Glass Manufacturing,   subclasses 33.1+ for a process of devitrifying of vitrifying glass combined with a glassworking operation.
117Single-Crystal, Oriented-Crystal, and Epitaxy Growth Processes; Non-Coating Apparatus Therefor,   for processes and non-coating apparatus for growing therein-defined single-crystal of all types of materials, including inorganic or organic.
127Sugar, Starch, and Carbohydrates,   subclasses 58+ for the crystallization of sugar.
159Concentrating Evaporators,   for processes for mere evaporation of a solution or suspension of a solid in a liquid whether or not the claims are directed to treatment of a definite chemical compound or element, unless such processes are provided for elsewhere. The combination of evaporation and significant crystallization is in this class (23).
203Distillation: Processes, Separatory,   subclass 48 for a distillation process including the step of crystallizing a material from a distillate or residue.
423Chemistry of Inorganic Compounds,   appropriate subclasses, for chemical processes of manufacturing inorganic compounds and nonmetallic elements which may involve crystallizing.
501Compositions: Ceramic,   subclasses 2+ for devitrified glass compositions, and subclass 86 for synthetic precious stone compositions.
  
[List of Patents for class 23 subclass 296]    296Selective:
 This subclass is indented under subclass 295.  Processes wherein preferential crystallization is carried out in a system containing two or more normally solid crystallizable constituents.
  
[List of Patents for class 23 subclass 297]    297With extraction:
 This subclass is indented under subclass 296.  Processes carried out in solution, in combination with a step of physical extraction or dissolving.

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423Chemistry of Inorganic Compounds,   appropriate subclasses, for extracting leaching or dissolving, per se.
  
[List of Patents for class 23 subclass 298]    298From natural sources:
 This subclass is indented under subclass 296.  Processes wherein the system being crystallized is found in nature, i.e., naturally occurring brines containing a number of salts.

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303,for processes of crystallizing Na Cl from brines containing this compound as the principal recoverable constituent.
  
[List of Patents for class 23 subclass 299]    299With extraction:
 This subclass is indented under subclass 295.  Processes combined with a step of physical extraction or dissolving, before or after crystallization.

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423Chemistry of Inorganic Compounds,   appropriate subclasses for extracting, leaching or dissolving, per se.
  
[List of Patents for class 23 subclass 300]    300With added material:
 This subclass is indented under subclass 295.  Processes wherein a substance is added to affect or cause crystallization.
(1) Note. This subclass includes salting out or addition of substances to control the size or shape of the crystals formed.
  
[List of Patents for class 23 subclass 301]    301Seed:
 This subclass is indented under subclass 300.  Processes wherein the added material is seed crystals.

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29Metal Working,   subclass 25.35 for processes of manufacturing piezo-electric crystal devices which include crystallizing and additional manufacturing operations.
  
[List of Patents for class 23 subclass 302]    302Alkali metal and ammonium compounds:
 This subclass is indented under subclass 295.  Processes in which the substance being crystallized is a compound of an alkali metal or ammonium.
  
[List of Patents for class 23 subclass 303]    303Common salt:
 This subclass is indented under subclass 302.  Processes in which the substance being crystallized is sodium chloride.

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423Chemistry of Inorganic Compounds,   subclasses 179 and 499.1 for processes of producing sodium chloride involving a chemical reaction.
  
[List of Patents for class 23 subclass 304]    304Alkaline earth metal and magnesium compounds:
 This subclass is indented under subclass 295.  Processes in which the substance being crystallized is a compound of an alkaline earth metal or magnesium.
  
[List of Patents for class 23 subclass 305]    305Heavy metal or aluminum compounds:
 This subclass is indented under subclass 295.  Processes in which the substance being crystallized is a compound of a heavy metal or aluminum.
  
[List of Patents for class 23 subclass 306]    306Concentration of liquids in liquids:
 This subclass is indented under subclass 293.  Processes involving concentration of solutions of liquids in liquids not otherwise provided for.

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274+,for apparatus for concentrating liquids in liquids.

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159Concentrating Evaporators,   for processes for concentrating solutions or suspensions of solids in liquids not more specifically provided for in other classes.
202Distillation: Apparatus,   subclasses 152+ and 232+ for separatory distillation apparatus.
203Distillation: Processes, Separatory,   subclasses 12+ for processes of distilling a liquid to separate only water.
  
[List of Patents for class 23 subclass 307]    307With direct heating:
 This subclass is indented under subclass 304.  Processes in which the liquid being concentrated is directly contacted with the concentrating medium (e.g., hot gases).

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203Distillation: Processes, Separatory,   subclass 49 for convective distillation.
  
[List of Patents for class 23 subclass 308]    308Melting out:
 This subclass is indented under subclass 293.  Processes drawn to or including as a significant step the melting out of fusible substances by heat.

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280,for melting separators.

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554Organic Compounds,   subclass 23 for processes of rendering fats, fatty oils or fatty oil acids. See also the notes thereto.
  
[List of Patents for class 23 subclass 313]    313Agglomerating:
 This subclass is indented under subclass 293.  Processes directed to the preparation of agglomerates from finely divided solid nonmetallic elements or inorganic compounds by treatments which cause coalescence of the particles.
(1) Note. The types of treatments usually employed are mechanical agitation and liquid treatment where the liquid is not a binder.

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156Adhesive Bonding and Miscellaneous Chemical Manufacture,   subclasses 62.2+ for processes of particle uniting combined with laminating.
264Plastic and Nonmetallic Article Shaping or Treating: Processes,   subclass 5 for particle formation by liquid comminuting, particularly subclass 6, with uniting of said particles, and subclasses 109+ for processes of forming articles by uniting of particulate material.
419Powder Metallurgy Processes,   appropriate subclasses for processes of forming articles by uniting particulate material containing metal particle.
425Plastic Article or Earthenware Shaping or Treating: Apparatus,   subclass 222 for tumbling type agglomerating apparatus for particulate material.
  
[List of Patents for class 23 subclass 314]    314Carbon:
 This subclass is indented under subclass 313.  Processes wherein the material undergoing agglomeration is carbon.
  

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