Pressure relief valve
AssigneeChicago Pneumatic Tool Company
InventorWilliam H. Schneider
Life of this patent
Estimating the term…
Abstract
A pressure relief valve for attachment to a tank, such as used on an electrical transformer, which valve will release excessive gas pressure developed in the tank because of transformer malfunction. The valve has a cap which uncovers a signal indicating portion of the valve when the valve is unseated during a pressure release operation. The cap remains in signal uncovered position, after the valve resets, to warn maintenance personnel that the tank has had an excessive pressure condition.
Claims6
A pressure relief valve comprising in combination, a valve body (12) having a threaded end (28) for mounting the valve upon an enclosure containing pressurized medium, a valve plunger (14) having a valve seating means (22, 38) at one end engageable with a valve seating surface (36) formed in the valve body to prevent release of pressurized medium from the enclosure and a tapered surface (40) which expands into a maximum diameter portion positioned near the other end of the plunger, a cap (18) slidingly supported upon the valve plunger and having a bearing surface (42) which is of less diameter than the maximum diameter portion of the tapered surface, a retainer (16) secured to the valve body and slidingly supporting the valve plunger, said retainer being arranged to allow flow of pressure medium thereby and into the cap, and a helical spring (20) compressively arranged between the plunger valve seating means and the retainer so that the valve is biased to seated condition, said valve body having an exterior signal surface (30) which is covered by the cap when the valve seating means is contacting the valve seating surface and is uncovered by the cap when the cap is moved by pressurized medium during pressure relief operation, and the cap bearing surface is forced upon the maximum diameter portion of the tapered surface.
Dependencies are inferred from the claim text.