US 4,180,177 AGranted

Pressure vent for explosion-proof electrical enclosures

AssigneeThe United States of America as represented by the Secretary of the Interior

InventorsRobert J. Gunderman, Keith Alcock, Charles S. Skinner, Michael W. Riley

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Abstract

A vent device for relieving pressure buildup inside an electrical enclosure due to an internal explosion of gases. A mass of stainless steel foam covers an opening in the enclosure and stops any flames or particles from escaping but provides a large equivalent cross section opening to permit the gases to escape and vent the pressure buildup. An outer cover protects the foam mass from impact damage and shields it from high pressure water spray used in cleaning. The cover is vertically hung from a knife-edge and held closed by means of a permanent magnet. A predetermined pressure differential is sufficient to overcome the attractive force of the magnet and allow the protective cover to be pushed open.

Claims7

Dependent claims

A pressure vent device, comprising:

(a) an enclosure for electrical apparatus,
(b) a vent opening extending from the interior to the exterior of the enclosure,
(c) flame arrestor means affixed in the opening for preventing flames from propagating through the opening in the event of an explosion of gases in the enclosure while permitting gas to vent through the opening at a predetermined pressure and a flow rate sufficient to preclude a pressure build-up,
(d) the enclosure including a seat surrounding the opening on the exterior side of the flame arrestor means,
(e) a cover sized and shaped to close the opening and fit against the seat for protecting the flame arrestor means,
(f) hinge means for connecting one edge portion of the cover to the enclosure while permitting an opposite edge portion to swing away from the seat,
(g) releasable latch means for holding said opposite edge portion against the seat until a predetermined pressure is reached in the enclosure,
(h) closing means for automatically returning said opposite edge portion into contact with the seat after the enclosure pressure drops below said predetermined pressure.

5 more elements

Dependencies are inferred from the claim text.