Check valve for RAT re-stow pump

Patent metadata

Field	Value
Publication number	US-12516665-B2
Application number	US-202418906902-A
Country	US
Kind code	B2
Filing date	Oct 4, 2024
Priority date	Oct 10, 2023
Publication date	Jan 6, 2026
Grant date	Jan 6, 2026

Abstract

A check valve assembly includes a valve body having a first end and a second end, the valve body extending along an axis (X) from the first end to the second end; a check valve outlet is located between the first and the second end; an actuator port provided in the check valve body at a location axially between the outlet and the second end, for fluid connection, in use, to a pump actuator. The valve body further includes a fluid inlet via which the check valve is, in use, connected to a fluid tank, the fluid inlet being provided in the valve body towards the second end, axially between the actuator port and the second end.

First claim

The invention claimed is:

1 . A pump unit comprising:
a pump housing containing a tank of pressurised fluid and having an outlet port via which fluid from the tank exits the pump unit; and a check valve assembly between the tank and the outlet port to regulate flow of the fluid from the tank to the port; and a pump actuator which cooperates with the check valve to regulate the fluid flow; wherein the check valve assembly comprises: a valve body having a first end and a second end, the valve body extending along an axis (X) from the first end to the second end such that the second end is lower than the first end; a check valve outlet is located between the first and the second end; an actuator port provided in the check valve body at a location axially between the outlet and the second end, for fluid connection, in use, to the pump actuator; the valve body further comprising a fluid inlet via which the check valve is, in use, connected to a fluid tank, the fluid inlet being provided in the valve body towards the second end, axially between the actuator port and the second end; the assembly further comprising: check valve components located in the check valve body configured to control the flow of fluid entering the check valve from the tank via the fluid inlet, and leaving the check valve via the outlet, according to the first and second stages of operation, the check valve components comprising a first ball located in the valve body adjacent the first end, and a second ball located in the valve body adjacent the second end, and a check valve spring provided in spring force engagement with the second ball, the check valve spring being sized and positioned to bias the second ball towards the second end; wherein a first stage pressure differential between the actuator port and the fluid inlet creates a fluid flow path from the inlet to the actuator port by causing the second ball to press against the bias of the check valve spring to create a flow passage between the second ball and the second end, and causing the first ball to block the flow of fluid to the outlet, and wherein removal of the first stage pressure differential causes the check valve spring to return the second ball to its biased position to close the passage from the fluid inlet to the actuator port and to cause the first ball to move to open a fluid passage between the actuator port and the outlet; wherein pump unit includes one piston, disposed in the pump actuator, and a piston cylinder within which the piston moves between a retracted position and an extended position relative to the cylinder, and whereby, in a first stage of pump operation, the piston is retracted to draw fluid from the tank into the cylinder via the check valve and, in a second stage of operation, after the first stage of operation, the piston is extended relative to the cylinder to eject fluid from the cylinder to the outlet port via the check valve, and wherein locating the inlet port at a lower end of the check valve, and fluid flow from the tank to the check valve is assisted by gravity and is thereby independent on a level of fluid in the tank.

2 . The pump unit of claim 1 , wherein the check valve assembly further comprises a cap at the first end of the valve body.

3 . The pump unit of claim 2 , wherein the check valve assembly further comprises a locking pin removably mountable through the valve body and the cap to secure the cap in place relative to the valve body.

4 . The pump unit of claim 1 , wherein the check valve assembly further comprises a retainer at the second end of the valve body.

5 . The pump unit of claim 4 , wherein the check valve assembly further comprises a safety wire to removably secure the retainer at the first end.

6 . The pump unit of claim 5 , wherein the check valve assembly further comprises seals provided between parts of the check valve assembly.

7 . The pump unit of claim 6 , wherein the valve body is provided with an external thread.

8 . The pump unit of claim 1 , further comprising:
a pump lever having a first end extending out of the pump housing for actuation by a user and a second end connected to the piston, such that movement of the lever moves the piston between the retracted and the extended positions.

9 . A ram air turbine (RAT) actuator assembly comprising:
a RAT actuator; and a pump unit as claimed in claim 1 , the RAT actuator connected to the outlet port.

10 . A ram air turbine (RAT) assembly comprising:
a RAT; and a RAT actuator assembly as claimed in claim 9 , arranged to stow the RAT.

11 . An aircraft having a ram air turbine (RAT) assembly as claimed in claim 10 .

12 . A check valve assembly comprising:
a valve body having a first end and a second end, the valve body extending along an axis (X) from the first end to the second end such that the second end is lower than the first end; a check valve outlet is located between the first and the second end; an actuator port provided in the check valve body at a location axially between the outlet and the second end, for fluid connection, in use, to a pump actuator; the valve body further comprising a fluid inlet via which the check valve is, in use, connected to a fluid tank, the fluid inlet being provided in the valve body towards the second end, axially between the actuator port and the second end; the assembly further comprising: check valve components located in the check valve body configured to control the flow of fluid entering the check valve from the tank via the fluid inlet, and leaving the check valve via the outlet, according to the first and second stages of operation, the check valve components comprising a first ball located in the valve body adjacent the first end, and a second ball located in the valve body adjacent the second end, and a check valve spring provided in spring force engagement with the second ball, the check valve spring being sized and positioned to bias the second ball towards the second end; wherein a first stage pressure differential between the actuator port and the fluid inlet creates a fluid flow path from the inlet to the actuator port by causing the second ball to press against the bias of the check valve spring to create a flow passage between the second ball and the second end, and causing the first ball to block the flow of fluid to the outlet, and wherein removal of the first stage pressure differential causes the check valve spring to return the second ball to its biased position to close the passage from the fluid inlet to the actuator port and to cause the first ball to move to open a fluid passage between the actuator port and the outlet.

13 . The check valve assembly of claim 12 , comprising a cap at the first end of the valve body and a retainer at the second end of the valve body, wherein a cap fastener differs from the retainer fastener.

14 . The check valve assembly of claim 13 , wherein the cap fastener is a locking pin removably mountable through the valve body and the cap to secure the cap in place relative to the valve body, and the retainer fastener is a safety wire to removably secure the retainer at the first end.

15 . The check valve assembly of claim 12 , further comprising seals provided between parts of the check valve assembly.

16 . The check valve assembly of claim 12 , wherein the valve body is provided with an external thread.

17 . A pump unit comprising:
a pump housing containing a tank of pressurised fluid and having an outlet port via which fluid from the tank exits the pump unit; and the check valve assem

Assignees

• Hamilton Sundstrand Corp

Inventors

• Kiełczykowski Przemysław
• Bereszyński Piotr Michał
• Słodczyk Damian

Classifications

• F16K15/044

  spring-loaded · CPC title

• F04B23/02

  having reservoirs · CPC title

• B64D41/007

  Ram air turbines · CPC title

• F16K27/0209

  Check valves or pivoted valves · CPC title

• F04B53/1002 Primary

  Ball valves · CPC title