VARIABLE BACK PRESSURE CHECK VALVE AND DRAIN VALVE

• US 3,665,950 A
• Filed: 07/13/1970
• Issued: 05/30/1972
• Est. Priority Date: 07/13/1970
• Status: Expired due to Term

• Current Assignee: Thomas A. Nelson
• Original Assignee: Thomas A. Nelson
• Inventors: Nelson, Thomas A.
• Primary Examiner(s): Rothberg, Samuel B.
• Assistant Examiner(s): Wright, William H.
• Application Number:
  US05/054,416
• Time in Patent Office: 687 Days
• Field of Search: 137/107,102,115,116.3,116
• US Class Current: 137/107
• CPC Class Codes: F02C 7/232 Fuel valves control of fuel supply by means of fuel metering valves F02C9/263; Draining valves or systems valves in general F16K
• CPC Class Codes: Y10T 137/2557 Waste responsive to flow stoppage
• CPC Class Codes: Y10T 137/2599 Venturi
• CPC Class Codes: Y10T 137/2607 With pressure reducing inlet valve
• CPC Class Codes: Y10T 137/7754 Line flow effect assisted

Abstract

A fluid receiver is connected via a supply orifice to a pressurized fluid supply source and via a fluid drain orifice to a relatively low pressure fluid drain source. A fluid pressure responsive spring-loaded check valve connected to the supply orifice and a drain valve connected to the drain orifice are provided with a one way collapsible link including a compression spring connecting the same causing the drain valve to open when the check valve is fully closed and close in response to compression of the spring when the check valve moves a predetermined distance in an opening direction. The check valve is provided with a contoured end portion and parallel flow passages in series flow therewith. One of the parallel flow passages includes a venturi for generating a fluid pressure which varies as a function of the flow therethrough and which is imposed on the check valve to assist the spring force acting thereagainst.

Claims

1. A variablE back pressure fluid flow check valve comprising:

a casing having an inlet connected to receive pressurized fluid at a variable flow rate and an outlet connected to a fluid receiver;

check valve means operatively connected to said inlet and outlet for controlling the effective flow area therebetween and thus the fluid pressure drop therebetween;

resilient means operatively connected to said valve means for imposing a predetermined force preload thereon tending to close the same in opposition to force derived from said pressurized fluid acting against said valve means;

fluid flow responsive means operatively connected in series flow relationship with said inlet and outlet for generating a control fluid pressure which varies as a function of the fluid pressure drop between said inlet and outlet; and

force producing means responsive to said control fluid pressure operatively connected to said valve means for imposing a force thereon to augment said resilient means.

2. A variable back pressure fluid flow check valve as claimed in claim 1 and further including:

a drain port in said casing connected to a relatively low pressure fluid drain source;

normally closed drain valve means operatively connected to said outlet and said drain port for establishing and disestablishing fluid communication therebetween; and

means operatively connecting said check valve means and said drain valve means for actuating said drain valve means to an open position in response to movement of said check valve means to a closed position and to a closed position in response to movement of said check valve means to an open position.

3. A variable back pressure fluid flow check valve as claimed in claim 1 wherein:

said check valve means is slidably carried in said casing and provided with first and second valve portions operative with said inlet and outlet, respectively, to define corresponding first and second variable flow areas;

conduit means including said fluid flow responsive means in series flow relationship with said first valve portion and in parallel flow relationship with said second valve portion;

said check valve means being operative over a first range of positions wherein said first valve portion is open and said second valve portion is closed with the resulting fluid flow through said inlet passing through said conduit means to said outlet and a second range of positions wherein said first valve portion is open and said second valve portion is open with the resulting fluid flow through said inlet passing through said second valve portion and said conduit means to said outlet.

4. A variable back pressure fluid flow check valve as claimed in claim 1 wherein:

said inlet defines an annular valve seat;

said check valve means is slidably carried in said housing and provided with a contoured end having a portion thereof adapted to seat on said valve seat to block said inlet;

a chamber formed in said housing downstream from said inlet;

a skirt formed on said check valve means and provided with a plurality of openings therein communicating with said chamber and adapted to register with said outlet to a varying degree depending upon the position of said check valve means;

a passage in said check valve means connecting said chamber with said outlet in parallel to said plurality of openings;

said fluid flow responsive means being disposed in said passage means and responsive to fluid flow therethrough;

said check valve means being actuable off said valve seat and having a first range of positions wherein said contoured end portion establishes a variable effective flow area of said inlet with said plurality of openings blocked and a second range of positions wherein said plurality of openings register with said outlet to vent fluid from said chamber to said outlet in parallel with fluid flow through said passage.

5. A variable back pressure fluid flow check valve as claimed in claim 4 wherein:

said resilient means is a compression spring urging said check valve means into seating engagement with said valve seat; and

said force producing means being defined by a predetermined effective area of said check valve means exposed to said control fluid pressure for generating a variable force augmenting said compression spring.

6. A variable back pressure fluid flow check valve as claimed in claim 2 wherein:

said means operatively connecting said check valve means includes a stop member fixedly secured to said check valve means and movable therewith;

said drain valve means being slidably carried on said check valve means and engageable with said stop member to limit the movement of said drain valve means relative to said check valve means; and

a compression spring interposed between said check valve means and said drain valve means for urging said drain valve means into engagement with said stop member.

7. A variable back pressure fluid flow check valve as claimed in claim 2 wherein:

said pressurized fluid is a controlled flow of fuel for a combustion engine;

said fluid receiver is a fuel manifold connected to supply said fuel to combustion chambers of the combustion engine; and

said relatively low pressure fluid drain source is a source of fuel.

8. A variable back pressure fluid flow valve as claimed in claim 6 wherein:

said inlet and said drain port are arranged in spaced apart co-axial relationship;

said check valve means and said drain valve means are arranged in spaced apart coaxial relationship and interposed between said inlet and said drain port in axial alignment therewith.

9. A variable back pressure fluid flow check valve as claimed in claim 3 wherein:

said fluid flow responsive means is a venturi wherein said control fluid pressure generated thereby varies as a function of fluid flow therethrough and thus the fluid pressure drop thereacross.