US PATENT SUBCLASS 454 / 171
.~ Having inlet and outlet ductwork

Current as of: June, 1999
Click HD for Main Headings
Click for All Classes

Internet Version by PATENTEC © 1999      Terms of Use


454 /   HD   VENTILATION

168  DF  MINE {3}
171.~ Having inlet and outlet ductwork

DEFINITION

Classification: 454/171

Having inlet and outlet ductwork:

(under subclass 168) Subject matter comprising conduit structure for admitting fresh ventilating air to the ventilated space and for exhausting stale air from the space.

(1) Note. The conduit structure (ductwork) must be distinct from the walls defining the mine excavation or gallery.