| 摘要 |
An improved piston in a check valve which prevents unintentional leakage past the check valve even at low pressures. The piston includes a generally-conically shaped tip and a Teflon ring received in a groove circumscribing the tip. The valve includes first and second passageways with an annular, generally conical seat therebetween. The piston is slidably received in the second passageway such that with fluid pressure applied towards the seat, the ring abuts the seat. The proximal portion of the tip adjacent the ring is inwardly relieved such that the outermost region of the ring is unsupported. When even a low pressure is applied, the ring contacts the seat and flexs or bends towards the relieved proximal portion to provide an effective low pressure seal between the ring and seat.
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