US PATENT SUBCLASS 55 / 520
SPIRAL FILTER MEDIA
Current as of: June, 1999
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DEFINITION
Classification: 55/520
(under the class definition) Apparatus comprising a filter element which is rolled or wound either in face-to-face or spaced relation to form one or more spiral convolutions.
SEE OR SEARCH THIS CLASS, SUBCLASS:
498, for filter sheet(s) edge supported in spiral form and subclass 484 for a spiral arrangement of spaced convolutions providing parallel flow for gas.
527, for a strand which is indiscriminately wound around itself, but not in a spiral.
