US PATENT SUBCLASS 95 / 273
FILTERING

Current as of: June, 1999
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95 /   HD   GAS SEPARATION: PROCESSES

273FILTERING {7}
274  DF  .~> Through particulate solids {2}
277  DF  .~> Moving filter
278  DF  .~> With cleaning of filter {3}
283  DF  .~> With heating of filter
284  DF  .~> And reduction of pressure
285  DF  .~> Coated or chemically treated filter
286  DF  .~> Plural separate media {1}

DEFINITION

Classification: 95/273

FILTERING:

(under the class definition) Process in which a gas and solid or liquid particles entrained therein are passed through a foraminous or porous mass which separates the solid or liquid particles from the gas by entrapment and retention while permitting the gaseous or vaporous constituents to pass through; and subcombinations of gas filtration processes that do not result in separation (e.g., cleaning of a filter, etc.) when the subcombinations are not provided for elsewhere.

(1) Note. A filter (particulate solids or other) has no "chemical" affinity for a constituent of a fluid mixture. The separation in the case of a filter depends on a mechanical entrapment of solid or liquid particles because of their relatively large size compared with the interstices or spaces between individual elements of the filter. The retained particles can be removed by brushing, wiping, shaking, or

similar mechanical action.

A solid sorbent is a solid material which separates a constituent (e.g., a gas, vapor, etc.) from a fluid mixture containing such constituents in a "quasi-chemical" manner. The action in most instances is that of selective retention (i.e., the sorbent removes only the part of the fluid mixture for which it has the greatest affinity). The retained constituent cannot be removed by shaking, brushing, or similar mechanical action, but generally can be removed by heating, pressure reduction, or use of a stripping or denuding fluid.

SEE OR SEARCH THIS CLASS, SUBCLASS:

214+, for processes of contacting a gas with a liquid and filtration of the gas.

268, for processes of filtering with deflection.

SEE OR SEARCH CLASS 55, Gas Separation, appropriate subclasses for filters.