초록 ▼

A valve having dual seats and dual poppets operating in series to function as either a conventional check valve, or may be operated by an independent piston which may be styled to either combine or eliminate the check valve feature. One seat poppet combination employes a metal-to-metal seal. The oth

A valve having dual seats and dual poppets operating in series to function as either a conventional check valve, or may be operated by an independent piston which may be styled to either combine or eliminate the check valve feature. One seat poppet combination employes a metal-to-metal seal. The other seat poppet combination utilizes a resilient o-ring seal vented so that when the seal is raised from the bottom of its groove, the upstream and downstream sides of the soft seat poppet can communicate. Alternative embodiments provide a family of zero leakage valves for different purposes, e.g. a check valve, pilot operated check valve, and an in line or balanced relief valve with or without the check valve feature by employing generally the same elements with modifications.

대표청구항 ▼

A zero leakage valve comprising: a valve body having an inlet port and an outlet port and a flow pasasge bore between said inlet and outlet ports; first and second fixed, circular valve seats concentrically arranged and axially located in said bore with said second seat larger than said first seat;

A zero leakage valve comprising: a valve body having an inlet port and an outlet port and a flow pasasge bore between said inlet and outlet ports; first and second fixed, circular valve seats concentrically arranged and axially located in said bore with said second seat larger than said first seat; a first poppet having a head at one end containing a generally retangular groove having a bottom and opposing sidewalls and containing a first resilient sealing means, at least one vent passage in said sidewall nearest said first poppet head end and adjacent said bottom of said groove and communicating to said head end of said first poppet, and a stem, said stem having a cross sectional area essentially equal to the area sealed by said first resilient sealing means in said first poppet head when engaging said first valve seat, axially located in said bore with said head oriented to oppose said first seat; support means to slideably support said stem of said first poppet to allow engagement of said first poppet head with said first valve seat; a second poppet having a head, oriented to oppose said second seat, and an aperture for slideably receiving said stem of said first poppet, so that said second poppet head may engage said second valve seat; second sealing means, between the engaging surfaces of said second poppet and the stem of said first poppet; biasing means urging said second poppet head against said second valve seat so that said second poppet unseats after and seats before said first poppet; a differential piston and cylinder adapted to axially move said piston responsive to applied pressure; a load spring biasing said differential piston in the direction to close said first and second poppets; and shoulder means on said stem of said first poppet to unseat said first and said second poppets, sequentially, and simultaneously compress said load spring when said differential piston is actuated so as to open said zero leakage valve.