Patent attributes
The present invention provides a pneumatic test plug that seals a portion of a pipe section having a generally cylindrical internal pipe wall. In general, the pneumatic test plug includes an inflation valve mounted in the bladder wall of an inflatable bladder. The inflation valve includes a main air passageway through which air is introduced into the bladder and a separate release channel. The separate release channel includes an inlet disposed toward an interior end of the inflation valve and an outlet in fluid communication with an exterior environment outside the bladder. When in a sealed position, a sealing portion of the bladder engages the interior end of the inflation valve and sealingly closes the inlet of the release channel. When the sealing portion is elastically deflected by overinflation of the bladder, the sealing portion uncovers the inlet of the release channel to allow air to escape from the interior area of the bladder through the release channel to the exterior environment.
