Low leakage relief valve

Patent metadata

Field	Value
Publication number	US-10288182-B2
Application number	US-201615158917-A
Country	US
Kind code	B2
Filing date	May 19, 2016
Priority date	Jun 10, 2015
Publication date	May 14, 2019
Grant date	May 14, 2019

Abstract

Provided is a relief valve with an inlet, and outlet, and a backside of a poppet fluidly connected to an input pressure to increasingly close the poppet as a function of input pressure until a prescribed pressure condition is reached. Upon the prescribed pressure condition being reached, the relief valve decreases pressure on the backside of the poppet to open the poppet and allow fluid flow from the inlet to the outlet. Increasingly closing the poppet allows the relief valve to operate under high pressure conditions and repeatedly open and close to reliable seal without significant leakage after thousands of cycles.

First claim

What is claimed is:

1. A relief valve assembly including:
a valve body having an inlet, an outlet and a valve seat;
a poppet having a piston portion and a valve portion for engaging at a front side of the valve portion the valve seat to block flow from the inlet to the outlet, the poppet being movable in the valve body and defining at a backside of the piston portion a biasing chamber;
a resilient member having a first end seated at the piston portion of the poppet and a second end seated on an adjustable stroke limiter disposed in the valve body, wherein the resilient member applies a biasing force on the poppet toward the valve seat, and wherein the biasing force is adjustable by the adjustable stroke limiter;
a pressure line configured to provide an input pressure to the biasing chamber to provide the input pressure to the backside of the poppet, whereby in a first state increasing the input pressure increases a force of the poppet against the valve seat to reduce leakage between the valve seat and the poppet;
an evacuation line for fluidly connecting the biasing chamber to a drain port; and
an unloading valve in the evacuation line for blocking fluid flow from the biasing chamber to the drain port, until pressure in the inlet exceeds a first pressure setting which causes the unloading valve to open to allow fluid flow through the evacuation line from the biasing chamber to the drain port, whereby in a second state pressure of fluid on the backside of the poppet is reduced below a predetermined proportion of an inlet pressure at the inlet while the front side of the valve portion is exposed to the inlet pressure to allow the poppet to move away from the valve seat against the biasing force of the resilient member thereby allowing fluid to flow between the valve seat and the poppet from the inlet to the outlet.

2. The relief valve assembly of claim 1 , wherein the pressure line fluidly connects the biasing chamber to fluid received at the inlet of the valve body for providing pressure of the fluid received at the inlet to the backside of the poppet, whereby in the first state increasing pressure of the fluid received at the inlet increases the force of the poppet against the valve seat to reduce leakage between the valve seat and the poppet.

3. The relief valve assembly of claim 1 , wherein the valve portion faces longitudinally away from the biasing chamber.

4. The relief valve assembly of claim 1 , wherein the drain port is fluidly connected to the outlet downstream of the valve seat.

5. The relief valve assembly of claim 1 , wherein a portion of the biasing chamber is defined by a cavity within the piston portion of the poppet, and wherein the first end of the resilient member is received within the cavity of the piston portion.

6. The relief valve assembly of claim 1 , wherein in a closed position the backside of the piston portion has a cross-sectional area greater than a cross-sectional area of a first portion of the front side of the valve portion exposed to the inlet pressure, by a cross-sectional area of the valve seat isolating a second portion of the front side from the inlet pressure.

7. The relief valve assembly of claim 1 , wherein the unloading valve includes an inlet port and a tank port fluidly connected to the evacuation line, whereby fluid from the biasing chamber flows into the inlet port and out of the tank port when the unloading valve is open.

8. The relief valve assembly of claim 7 , further including an evacuation signal line fluidly connected to an evacuation signal port of the unloading valve for signaling the unloading valve to open above a prescribed pressure.

9. The relief valve assembly of claim 1 , wherein the pressure line is an inlet pressure line that fluidly connects the biasing chamber to the inlet for providing the inlet pressure to the backside of the poppet, whereby in the first state increasing pressure of fluid at the inlet increases the force of the poppet against the valve seat to reduce leakage between the valve seat and the poppet.

10. The relief valve assembly of claim 9 , further including a first signal line fluidly connecting the inlet to the unloading valve.

11. The relief valve assembly of claim 9 , wherein the unloading valve includes a signal port fluidly connected to a first signal line fluidly connected to the inlet pressure line and configured to open at a predetermined pressure, thereby allowing fluid from the biasing chamber to pass through the unloading valve to a drain line.

12. The relief valve assembly of claim 9 , further including an orifice in the inlet pressure line, wherein the orifice is configured to reduce fluid flow from the inlet into the biasing chamber below a maximum flow rate of the unloading valve.

13. The relief valve assembly of claim 12 , wherein the orifice is disposed external to the poppet and the valve body and is disposed downstream of a first signal line that fluidly connects the inlet pressure line to the unloading valve.

14. A method of relieving pressure in a hydraulic circuit:
providing inlet pressure from an inlet to a backside of a poppet for urging the poppet against a valve seat with a closing force proportionally related to the inlet pressure for urging the poppet closed with increasing force as the inlet pressure increases, wherein a resilient member having a first end seated at the backside of the poppet and a second end seated on an adjustable stroke limiter applies a biasing force on the poppet toward the valve seat, and wherein the biasing force is adjustable by the adjustable stroke limiter;
providing the inlet pressure at a front side of the poppet for urging the poppet away from the valve seat with an opening force proportionally related to the inlet pressure; and
upon the inlet pressure exceeding a prescribed amount, evacuating pressure at the backside of the poppet for allowing the inlet pressure to force the poppet open, thereby allowing fluid flow between the poppet and the valve seat from the inlet to an outlet.

15. The method of relieving pressure of claim 14 , further including closing the poppet using the inlet pressure, thereby preventing fluid flow from the inlet to the outlet.

16. The method of relieving pressure of claim 14 , wherein the poppet has a valve portion configured to engage the valve seat when the poppet is urged against the valve seat, wherein the poppet is hollow and defines a cavity therein, the method further including providing the inlet pressure to the cavity of the poppet, thereby expanding at least a portion of the valve portion of the poppet to decrease sealing imperfections against the valve seat.

17. A relief valve including:
a valve body having an inlet, an outlet, a valve seat, an inlet pressure port, and an evacuation port;
a poppet having a piston portion and a valve portion for engaging at a front side of the valve portion the valve seat to block flow from the inlet to the outlet, the poppet being movable in the valve body and defining at a backside of the piston portion a biasing chamber; and
a resilient member having a first end seated at the piston portion of the poppet and a second end seated on an adjustable stroke limiter disposed in the valve body, wherein the resilient member applies a biasing force on the poppet toward the valve seat, and wherein the biasing force is adjustable by the adjustable stroke limiter,
wherein the inlet pressure port is connectable to an inlet pressure line to fluidly connect the biasing chamber to the inlet for providing inlet pressure from the inlet to the backside of the piston portion, whereby in a f

Assignees

• Parker Hannifin Corp

Inventors

• Thompson Jesse

Classifications

• F16K17/06

  with special arrangements for adjusting the opening pressure · CPC title

• F16K17/048 Primary

  combined with other safety valves, or with pressure control devices · CPC title