摘要 |
A plug having a pressure release valve for releasing excess pressure within a bladder of the plug. The release valve has a valve core with a pressure release passage therethrough with an inlet in fluid communication with an interior void of the bladder and an outlet in fluid communication with the external environment outside the bladder. An elastomeric seal under hoop stress about a portion of the valve core seals the outlet until overinflation of the bladder causes the seal to become elastically deflected and unseal the outlet, thereby allowing excess pressure to be released. When the overinflation no longer exists because of the pressure release, the hoop stress of the seal causes resealing of the outlet. An inflation valve may also be provided to inflate the bladder, and with the inlet opening into an inflation passageway into the bladder's interior.
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