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Valve apparatus for providing shutoff and overspeed protection in a gas turbine fuel system

  • US 6,401,446 B1
  • Filed: 06/23/2000
  • Issued: 06/11/2002
  • Est. Priority Date: 06/23/2000
  • Status: Expired due to Term
First Claim
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1. A valve pack for use in a fuel delivery system for providing a desired fuel flow to an engine, the fuel deliver system including a metering valve having a metering state where the metering valve provides a metered fuel flow to the engine in response to a pressure differential between a reference pressure chamber and a modulated pressure chamber of the valve and a shutoff state wherein the metering valve blocks fuel flow to the engine in response to a pressure differential between the reference and modulated pressure chambers;

  • the valve pack comprising;

    a fuel inlet port to receive a metered fuel flow from the fuel metering valve;

    a fuel outlet port to selectively receive the metered fuel flow from the fuel inlet port to direct the metered fuel flow to the engine;

    an actuation pressure inlet port selectively connected to a drain to transfer an actuation fuel flow to the drain;

    a reference pressure inlet port to receive fuel flow at a reference pressure;

    a reference pressure outlet port to selectively receive the fuel flow at the reference pressure form the reference pressure inlet port to transfer the fuel flow to a modulated pressure chamber of the fuel metering valve;

    an overspeed activation port; and

    a shutoff activation port;

    the valve pack having an overspeed state in response to the overspeed activation port being placed in fluid communication with a drain, a shutoff state in response to the shutoff activation port being placed in fluid communication with a drain and flow from the overspeed activation port to the drain being blocked, and a run state with flow from both of the overspeed and shutoff activation ports to the drain being blocked;

    with the valve pack in the overspeed state, the reference pressure inlet port is connected to the reference pressure outlet port to direct fuel flow at the reference pressure from the reference pressure inlet port to the modulated pressure chamber of the fuel metering valve, the actuation pressure inlet port is opened to receive a fuel flow, and flow from the fuel inlet port to the fuel outlet port is blocked to shutoff the metered fuel flow to the engine;

    with the valve pack in the shutoff state, the actuation pressure inlet port is opened to receive a fuel flow, fuel flow from the reference pressure inlet port to the reference pressure outlet port is blocked, and fuel flow from the fuel inlet port to the fuel outlet port is blocked to shutoff the metered fuel flow to the engine;

    with the valve pack in the run state, the fuel inlet port is connected to the fuel outlet port to direct the metered fuel flow from the fuel inlet port to the engine, fuel flow from the reference pressure inlet port to the reference pressure outlet port is blocked, and the actuation pressure inlet port is closed;

    a first valve spool positioned in the valve pack to block fuel flow from the fuel inlet port to the fuel outlet port with the valve pack in the overspeed state and with the valve pack in the shutoff state; and

    a second valve spool positioned in the valve pack to block fuel flow through the actuation pressure inlet port with the valve pack in the run state.

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