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Metering valve

  • US 5,295,654 A
  • Filed: 03/01/1993
  • Issued: 03/22/1994
  • Est. Priority Date: 03/01/1993
  • Status: Expired due to Term
First Claim
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1. A metering valve for controlling fluid flow between a fluid inlet and fluid outlet, comprising a piston assembly for mounting between the fluid inlet and outlet and for relative movement within a tubular unit having an interior surface first section bore providing sealing engagement with said piston assembly and a second section bore large enough to prevent sealing engagement with said piston assembly;

  • said piston assembly operative in a first open mode, a second open mode and a close mode and being biased to assume a close mode in which said piston assembly is disposed in non-sealing relation with the tubular unit interior surface second section; and

    an elongate valve actuating member having an exposed one end portion extending from a first end of the tubular unit, a second end portion extending from a second end of the tubular unit and an enlarged section disposed intermediate said end portions;

    said member second end portion including a first valve component actuated to an open position when a predetermined first external force is applied to said member one end portion, said piston assembly thereby assuming the first open mode in which fluid from said inlet through said first valve component fills a first cavity adjacent said piston assembly toward said tubular unit first end;

    said piston assembly including a second valve component actuated to an open position upon engagement by said enlarged section when a predetermined second external force is applied to said member one end portion, said piston assembly thereby moving within said tubular unit and assuming the second open mode in which said first cavity fluid volume is increased and said piston assembly is disposed in sealing relation with the tubular unit interior surface first section and direct interconnection between the fluid inlet and outlet is effected;

    upon the predetermined first and second external forces being released, said piston assembly automatically returning to the close mode upon successively moving through first and second segments of travel relative to said tubular unit;

    said piston assembly being in sliding sealing engagement with the tubular unit interior surface first section when moving through said first segment of travel whereby movement of said piston assembly is retarded as the fluid in said first cavity is slowly dissipated through a metering port in said piston assembly toward a side of said piston assembly opposite said first cavity, thereby allowing a predetermined volume of fluid to flow through the metering valve, said piston assembly being in a non-sealing relation with the tubular unit interior surface second section when said piston assembly move through the second segment of travel whereby said piston assembly relative motion is substantially instantaneous to the close mode as the fluid in said first cavity is quickly dissipated toward said opposite side between said piston assembly and said tubular unit interior surface second section, thereby halting further fluid flow through the metering valve.

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