US PATENT SUBCLASS 423 / 210
MODIFYING OR REMOVING COMPONENT OF NORMALLY GASEOUS MIXTURE

Current as of: June, 1999
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423 /   HD   CHEMISTRY OF INORGANIC COMPOUNDS

210MODIFYING OR REMOVING COMPONENT OF NORMALLY GASEOUS MIXTURE {11}
210.5  DF  .~> Direct contact with molten material
212  DF  .~> Mixture is exhaust from internal-combustion engine {1}
219  DF  .~> Molecular oxygen or ozone component
220  DF  .~> Carbon dioxide or hydrogen sulfide component {9}
235  DF  .~> Nitrogen or nitrogenous component {3}
240 R  DF  .~> Halogenous component {2}
242.1  DF  .~> Sulfur or sulfur containing component {3}
245.1  DF  .~> Organic component {2}
246  DF  .~> Carbon monoxide component {1}
248  DF  .~> Hydrogen component
215.5  DF  .~> Solid component

DEFINITION

Classification: 423/210

(under the class definition) Processes in which an initial gaseous or vaporous mixture is treated so as to remove therefrom or change to a different chemical form at least one of the components therein, resulting in a heterogeneous composition.

(1) Note. As between coordinate subclasses distinguished by specified chemical components, the original placement of a patent is in the first appearing subclass providing for a component which has been chemically modified.

(2) Note. A chemical reaction must be involved in the process.

(3) Note. Wherever the recovery of a definite chemical compound or element as a product is claimed, original classification of the patent is in the subclass following subclass 215.5 which provides for the compound or element. However, where the claim does not include the step of separating the modified component, the patent is classified here (subclasses 210+) even though disclosed intent is to ultimately effect separation of the component.

(4) Note. The mixture need not be entirely gaseous; it may contain entrained solids or liquids. It must however be handled and distributed as a gas and must be in this form at the onset of the treatment.

SEE OR SEARCH THIS CLASS, SUBCLASS:

264, for rendering an impurity ineffective in a process in which either the starting mixture is not gaseous, or if gaseous, the intent is to make a compound; see preceding notes. SEE OR SEARCH CLASS

95, Gas Separation: Processes, appropriate subclasses, for processes of purifying a gaseous mixture or separating a

constituent therefrom where no chemical reaction is involved in the separation or purification, per se. In this respect sorption on a solid (e.g., silica gel, charcoal etc.) or in water even of gases such as NH3, SO3, etc. which may form alkalis or acids with the water is considered to be a nonchemical separation proper for Class 95. However, adsorption on a basic or acidic solid, or absorption in acid or a base is considered to be a chemical reaction and proper for Class 423,

210+, unless the acid or base is the solvent for itself, i.e., hydrochloric acid for gaseous hydrogen chloride, sulfuric acid for sulfur trioxide, etc.

102, Ammunition and Explosive,

23, for blasting methods which include procedures for fume control.

149, Explosive and Thermic Compositions or Charges,

108.4, for subject matter of that class drawn to control of the smoke or gas produced.

260, Chemistry of Carbon Compounds, appropriate subclasses for preparation and treatment of organic materials.

431, Combustion, for processes of burning exhaust gases where the intent is to use the gas as a fuel primarily and not to separate or purify the gas. Note

224, in Class 423 where combustion is used to purify or separate a gas.

588, Hazardous or Toxic Waste Destruction or Containment, appropriate subclasses for treatment of gaseous, hazardous, or toxic waste.