Valve construction

In a conduit stopper for use with a nozzle, said nozzle sealingly mounted on an elongated conduit, said conduit stopper selectively interrupting the flow of a fluid through the interior of the conduit, said conduit having an aperture communicating with the nozzle for receiving the conduit stopper, said conduit stopper having a linear actuator connected thereto, said conduit stopper including a plug holder connected to the linear actuator for movement of the plug holder within the nozzle, the improvement comprising a retainer cap connected to the plug holder moveable longitudinally within the nozzle, said retainer cap having a cylindrical sidewall within said nozzle and extending along a length therein toward said apertures, an elongated deformable sealing element having one end secured in the retainer cap and an opposite end positioned in the interior of the conduit for sealing engagement therewith to interrupt the flow of fluid through the conduit, said cylindrical sidewall having internally thereof means to secure the one end of the sealing element to the interior of the retainer cap, whereby deformation of said opposite end of the sealing element by fluid pressure in the conduit does not affect the retention of the one end of the sealing element in the cylindrical sidewall and in the nozzle to maintain a seal in the conduit and at the aperture to prevent leakage in the nozzle.