Patent ID: 8256467
Filing Date: 2012-09-04
Classification: F16K,F16L,Y10T

Abstract:
1. A plug for use in sealing a pipe having a generally cylindrical internal pipe wall, said plug comprising an inflatable bladder having an interior void defined within said bladder; said plug further comprising a pressure release valve being mounted into an end of said plug, said pressure release valve including: (a) a valve core having a pressure release passageway therethrough, said pressure release passageway having a pressure release inlet in fluid communication with said interior void and further having a pressure release outlet in selective fluid communication with an exterior environment outside said bladder, said pressure release inlet and said pressure release outlet being joined by a bore through said valve core; (b) an elastomeric seal having a first seal portion always under hoop stress about a portion of said valve core and selectively sealing said pressure release outlet from said exterior environment, wherein, when overinflation of said bladder occurs, said first seal portion becomes elastically deflected to unseal said pressure release outlet from said exterior environment and thereby allow excess fluid pressure within said bladder to be released through said pressure release passageway and out said pressure release outlet into said exterior environment, said hoop stress causing said first seal portion to reseal said pressure release outlet from said exterior environment after sufficient excess fluid pressure within said bladder has been released.