U.S. PATENT AND TRADEMARK OFFICE
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U.S. Patent Classification System - Classification Definitions
as of June 30, 2000
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Classification Index
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Class 023
CHEMISTRY: PHYSICAL PROCESSES
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
Subclass:
293
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.
SEE OR SEARCH CLASS:
34, Drying and Gas or Vapor Contact With Solids, for drying
processes.
53, Package 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.
62, Refrigeration, subclasses 600+ for processes and
apparatus specialized to the manufacture of a solidified or
liquefied product from a gas by physical treatment only.
75, Specialized 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.
95, Gas Separation: Processes, for physical processes of gas
separation and purification.
100, Presses, subclasses 35+ for processes for compacting
material, not elsewhere provided for.
127, Sugar, Starch, and Carbohydrates, for processes of
extracting and crystallizing sugar.
159, Concentrating Evaporators, for processes of
concentrating solutions or suspensions of solids in liquids.
201, Distillation: Processes, Thermolytic, appropriate
subclasses for a destructive distillation process.
203, Distillation: Processes, Separatory, appropriate
subclasses for a separatory distillation process.
209, Classifying, Separating, and Assorting Solids, for
processes of separating solids from solids.
210, Liquid 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.
241, Solid 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.
261, Gas and Liquid Contact Apparatus, for processes for
contacting gases and liquids when for a purpose other than
that of gas separation or purification.
264, Plastic 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.
366, Agitating, for mixing or agitating processes.
422, Chemical 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).
426, Food or Edible Material: Processes, Compositions, and
Products, appropriate subclasses for physical processes
involving foods.
432, Heating, subclasses 1+ for a material heating process
of general utility.
494, Imperforate 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.
Subclass:
294
This subclass is indented under subclass 293. Processes
directed to or including sublimation as a significant step.
SEE OR SEARCH CLASS:
266, Metallurgical Apparatus, subclasses 144+ for
metallurgical furnaces with fume arresters.
Subclass:
295
This subclass is indented under subclass 293. Processes
directed to or including crystallization as a significant
step.
SEE OR SEARCH CLASS:
29, Metal Working, subclass 25.35 for processes of
manufacturing piezo-electric crystal devices which include
crystallizing and additional manufacturing operations.
62, Refrigeration, for processes of crystallization including
a step of refrigeration, especially see subclasses 66+ and
subclasses 532+.
65, Glass Manufacturing, subclass 33.1 for a process of
devitrifying of vitrifying glass combined with a glassworking
operation.
117, Single-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.
127, Sugar, Starch, and Carbohydrates, subclasses 58+ for
the crystallization of sugar.
159, Concentrating 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).
203, Distillation: Processes, Separatory, subclass 48 for a
distillation process including the step of crystallizing a
material from a distillate or residue.
423, Chemistry of Inorganic Compounds, appropriate
subclasses, for chemical processes of manufacturing inorganic
compounds and nonmetallic elements which may involve
crystallizing.
501, Compositions: Ceramic, subclasses 2+ for devitrified
glass compositions, and subclass 86 for synthetic precious
stone compositions.
Subclass:
296
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.
Subclass:
297
This subclass is indented under subclass 296. Processes
carried out in solution, in combination with a step of
physical extraction or dissolving.
SEE OR SEARCH CLASS:
423, Chemistry of Inorganic Compounds, appropriate
subclasses, for extracting leaching or dissolving, per se.
Subclass:
298
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.
SEE OR SEARCH THIS CLASS, SUBCLASS:
303 for processes of crystallizing Na Cl from brines
containing this compound as the principal recoverable
constituent.
Subclass:
299
This subclass is indented under subclass 295. Processes
combined with a step of physical extraction or dissolving,
before or after crystallization.
SEE OR SEARCH CLASS:
423, Chemistry of Inorganic Compounds, appropriate subclasses
for extracting, leaching or dissolving, per se.
Subclass:
300
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.
Subclass:
301
This subclass is indented under subclass 300. Processes
wherein the added material is seed crystals.
SEE OR SEARCH CLASS:
29, Metal Working, subclass 25.35 for processes of
manufacturing piezo-electric crystal devices which include
crystallizing and additional manufacturing operations.
Subclass:
302
This subclass is indented under subclass 295. Processes in
which the substance being crystallized is a compound of an
alkali metal or ammonium.
Subclass:
303
This subclass is indented under subclass 302. Processes in
which the substance being crystallized is sodium chloride.
SEE OR SEARCH CLASS:
423, Chemistry of Inorganic Compounds, subclass 179 and
499.1 for processes of producing sodium chloride involving a
chemical reaction.
Subclass:
304
This subclass is indented under subclass 295. Processes in
which the substance being crystallized is a compound of an
alkaline earth metal or magnesium.
Subclass:
305
This subclass is indented under subclass 295. Processes in
which the substance being crystallized is a compound of a
heavy metal or aluminum.
Subclass:
306
This subclass is indented under subclass 293. Processes
involving concentration of solutions of liquids in liquids
not otherwise provided for.
SEE OR SEARCH THIS CLASS, SUBCLASS:
subclasses 274+ for apparatus for concentrating liquids in
liquids.
SEE OR SEARCH CLASS:
159, Concentrating Evaporators, for processes for
concentrating solutions or suspensions of solids in liquids
not more specifically provided for in other classes.
202, Distillation: Apparatus, subclasses 152+ and 232+ for
separatory distillation apparatus.
203, Distillation: Processes, Separatory, subclasses 12+
for processes of distilling a liquid to separate only water.
Subclass:
307
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).
SEE OR SEARCH CLASS:
203, Distillation: Processes, Separatory, subclass 49 for
convective distillation.
Subclass:
308
This subclass is indented under subclass 293. Processes drawn
to or including as a significant step the melting out of
fusible substances by heat.
SEE OR SEARCH THIS CLASS, SUBCLASS:
280 for melting separators.
SEE OR SEARCH CLASS:
554, Organic Compounds, subclass 23 for processes of
rendering fats, fatty oils or fatty oil acids. See also the
notes thereto.
Subclass:
313
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.
SEE OR SEARCH CLASS:
156, Adhesive Bonding and Miscellaneous Chemical Manufacture,
subclass 62.2 for processes of particle uniting combined
with laminating.
264, Plastic 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.
419, Powder Metallurgy Processes, appropriate subclasses for
processes of forming articles by uniting particulate material
containing metal particle.
425, Plastic Article or Earthenware Shaping or Treating:
Apparatus, subclass 222 for tumbling type agglomerating
apparatus for particulate material.
Subclass:
314
This subclass is indented under subclass 313. Processes
wherein the material undergoing agglomeration is carbon.
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Last Modified: 6 October 2000