Flash back arrestor

A pressure release valve for a flash back arrestor comprising in combination a housing having a wall, means defining a first outlet passage through said wall, a valve seat surrounding said passage, a valve member slidable in a bore in said housing and means biasing said valve member toward said valve seat, means defining a space outwardly of said valve seat, means defining a second passage through said wall to the outside communicating with said space, said valve member being in the shape of a sleeve defining a passage communicating the inside of the housing with said first passage, the diameter of the valve seat being greater than the inner diameter of said sleeve whereby said sleeve has a pressure surface facing said first passage and excessive pressure in said first passage will force said valve member against the biasing means away from the valve sent to communicate the first passage to said space.

A safety device for automatically interrupting a flash back through a gas supply conduit comprising in combination a housing having an inlet and an outlet chamber means, defining an elongated passageway intercommunicating said chambers, a valve between said inlet chamber and the inlet to said elongated passageway, said valve comprising a valve seat and a valve member freely slidable in sealed relationship with said housing on a line of movement from a normal first position spaced from said valve seat to a second position where a first surface on one end thereof is in sealing engagement with said valve seat, said valve member having a second surface on the opposite end exposed to pressure in said outlet chamber whereby high pressures in said outlet chamber from a flash back will move said valve member from said first position to said second position and latching means biasing said valve member to said second position after said valve member has moved a predetermined distance from said first position to said second position.

A housing for a flash back arrestor comprised of a first sleeve, first and second ends closing respective opposite ends of said sleeve, a second sleeve inside said first sleeve extending from said first end toward but spaced from the second end and spaced from the inner wall of said first sleeve and defining therebetween a space, means defining a chamber in said second end, a tube in the shape of a helix in said space having an end communicating with said chamber, the other end of said tube opening to said space and flash pressure actuated valve means movable under flash pressures in said second sleeve to close off the communication between said chamber and said tube.

A flash back arrestor comprising in combination an elongated housing having first and second ends, an inlet passage in said first end, a pressure-actuated valve in said passage, an elongated tube in said housing having an inlet passage communicating with the outlet of said pressure-actuated valve and an outlet end communicating with the inside of said housing, said pressure-actuated valve including a piston member having a first valve open and a second valve closed position and having a pair of oppositely facing surfaces, one exposed to pressure at the outlet and the other exposed to pressure at the inlet end of said tube, said piston member being freely movable from said first position to said second position when pressures at the outlet end of said tube exceed pressures at the inlet end of said tube, and means latching said piston member against movement when it has moved to a closed position under such pressure differential.