Valve and actuator assembly

Abstract

A valve and actuator assembly having a mechanism adapting such assembly for remote actuation by a pressure medium such as hydraulic or pneumatic fluid and including means for controlling the development of resultant forces acting upon the valve stem of the valve. The valve and actuator assembly includes safety means for rendering the valve safe in response to the development of predetermined unsafe conditions and is adapted with a manual override system allowing the valve to be manually opened or closed regardless of the condition of the safety means. Mechanical or fluid actuated interlock means is provided to render fluid actuating means inoperative and is also provided with means for rendering the mechanical override inoperative. The assembly is adapted to lock out the fluid actuator system to allow the assembly to be serviced without risk of inadvertent actuation by automatic systems. Effluent pressure may be communicated to the outer extremity of the valve stem to balance the force applied to the inner extremity of the valve stem by effluent pressure within the valve.

Having thus fully described my invention, I claim: 
     
       1. A valve and actuator assembly comprising: valve body means defining a valve chamber and having flow passage means intercepting said valve chamber;   seat means disposed within said valve chamber about said flow passage means;   gate means being movably disposed within said valve chamber and having sealing engagement with said seat means, said gate having a flow port for registry with said flow passage means to conduct the flow of effluent through said valve and having an imperforate portion to block the flow of effluent;   bonnet means defining a closure for said valve chamber;   fluid motor means being carried by said bonnet means and having piston means movably disposed therein;   valve stem means having upper and lower extremities, the lower extremity being connected to said gate means and being connected to said piston means, said valve stem means cooperating with said valve body to define a first pressure responsive area of said stem means;   stem drive means engaging said stem means and being operative to impart reciprocal movement to said stem means;   balancing means carried by said stem means and cooperating with said stem drive means to define a second pressure responsive area of said stem means; and   means communicating effluent pressure from said valve chamber to each extremity of said valve stem and causing pressure induced forces acting on said first and second pressure responsive areas of said stem to be substantially balanced.   
     
     
       2. A valve and actuator assembly as recited in claim 1: said fluid motor means comprising a closed piston housing being fixed to said bonnet and having top and bottom walls and a generally cylindrical wall;   said piston dividing said housing into first and second chambers;   means communicating pressurized actuating fluid into said first chamber to impart movement to said piston and said valve stem in one direction;   means venting said second chamber; and   means urging said piston in a direction opposing said one direction.   
     
     
       3. A valve and actuator assembly as recited in claim 1: said means communicating effluent pressure from said valve chamber to each extremity of said valve stem comprising passage means defined axially through said valve stem.   
     
     
       4. A valve and actuator assembly as recited in claim 1: said stem having threads formed thereon;   said stem drive means comprising a tubular stem drive element received in surrounding relation about the outer extremity of said stem, said drive element having internal threads at the lower extremity thereof, said threads being disposed in threaded engagement with said stem;   means establishing a first seal between said valve bonnet and said stem and defining a first pressure responsive cross-sectional area on said stem;   a pressure balancing piston carried by said stem and establishing a second seal between said stem drive means and said stem and defining a second pressure responsive cross-sectional area; and   said means communicating effluent pressure from said valve chamber to each extremity of said valve stem causing said effluent pressure to act simultaneously on said first and second cross-sectional areas.   
     
     
       5. A valve and actuator assembly as recited in claim 4: said means establishing said first seal comprising a first packing retained within said bonnet and disposed in dynamic sealed engagement with said valve stem.   
     
     
       6. A valve and actuator assembly as recited in claim 4: said pressure balancing piston comprising a second packing being carried by said valve stem and disposed in dynamic sealed engagement with the inner surface of said tubular drive element.   
     
     
       7. A valve and actuator assembly as recited in claim 4: said means establishing said first seal comprising a first packing retained within said bonnet and disposed in dynamic sealed engagement with said valve stem; and   said pressure balancing piston comprising a second packing being carried by said valve stem and disposed in dynamic sealed engagement with the inner surface of said tubular drive element.   
     
     
       8. A valve and actuator assembly as recited in claim 7: vent passage means being defined in said tubular drive element and venting any leakage of effluent pressure of said second packing into said fluid motor means.   
     
     
       9. A valve and actuator assembly as recited in claim 4: said fluid motor means comprising a piston housing being fixed to said bonnet and having top and bottom walls and a generally cylindrical wall;   said tubular drive element extending through said top wall in sealed relation therewith; and   means closing the outer extremity of said tubular stem drive element and defining a pressure balancing chamber outwardly of said valve stem.   
     
     
       10. A valve and actuator assembly as recited in claim 9: said means communicating effluent pressure from said valve chamber to each extremity of said valve stem comprising an effluent passage formed in said valve stem; and   said effluent passage conducting pressurized effluent from said valve chamber to said pressure balancing chamber.   
     
     
       11. A valve and actuator assembly as recited in claim 4: said first and second cross-sectional areas being of substantially equal dimension.   
     
     
       12. A valve and actuator assembly as recited in claim 4: said first and second cross-sectional areas being of different dimension.   
     
     
       13. A valve and actuator assembly as recited in claim 4: means for blocking communication between said valve chamber and the outer extremity of said valve stem in at least one position of said stem.   
     
     
       14. A valve and actuator assembly as recited in claim 13: said means for blocking communication between said valve chamber and the outer extremity of said valve stem comprising a first seat surface defined on said stem inwardly of said passage means;   a second seat surface defined by said bonnet; and   said first and second seat surfaces being brought into sealed engagement upon movement of said stem to the outermost position thereof.   
     
     
       15. A valve and actuator assembly comprising: valve body means defining a valve chamber and having flow passge means intercepting said valve chamber;   gate means being movably disposed within said valve chamber and having a flow port for registry with said flow passage means to conduct the flow of effluent through said valve and having a solid portion to block the flow of effluent;   bonnet means defining a closure for said valve chamber;   a fluid motor being carried by said bonnet and having a housing defined by top and bottom walls and a generally cylindrical wall;   a piston being .[.removably.]. .Iadd.movably .Iaddend.disposed within said housing and dividing said housing into first and second chambers;   means communicating pressurized actuating fluid into said first chamber to impart movement to said piston and said valve stem in one direction;   means venting said second chamber;   means imparting a force to said piston in a direction opposing said one direction;   valve stem means interconnecting said gate means and said piston, said valve stem having upper and lower extremities and cooperating with said valve body to define a first pressure responsive area of said stem;   stem drive means engaging said stem means and being operative to impart reciprocal movement to said stem means;   balancing means carried by said stem means and cooperating with said stem drive means to define a second pressure responsive area of said stem means; and   means communicating effluent pressure from said valve chamber to each extremity of said valve stem and causing pressure induced forces acting on said first and second pressure responsive areas of said stem to be substantially balanced.   
     
     
       16. A valve and actuator assembly as recited in claim 15: said stem drive means being a tubular stem drive element received about the outer extremity of said stem and being disposed in threaded engagement with said stem;   means establishing a first seal between said valve bonnet and said stem and defining a first cross-sectional area of said stem;   means establishing a second seal between said stem drive means and said stem and defining a second cross-sectional area of said stem; and   said means communicating effluent pressure from said valve chamber to each extremity of said valve stem causing said effluent pressure to act simultaneously on said first and second cross-sectional areas.   
     
     
       17. A valve and actuator assembly as recited in claim 15: said stem drive means being a tubular stem drive element received about the outer extremity of said stem and being disposed in threaded engagement with said stem;   a first packing being retained within said valve bonnet and being disposed in dynamic sealed engagement with said valve stem; and   second packing means being carried by said valve stem and disposed in dynamic sealed engagement with said tubular drive element.   
     
     
       18. A valve and actuator assembly as recited in claim 17: said tubular drive element extending through said top wall in sealed relation therewith;   means for imparting movement to said tubular drive element.   
     
     
       19. A valve and actuator assembly as recited in claim 18: bearing means being carried by said closed housing of said fluid motor;   flange means being carried by said tubular stem drive element; and   said flange means being engagable with said bearing means to restrict outward movement of said tubular stem drive element.   
     
     
       20. A valve and actuator assembly as recited in claim 15: means for venting any effluent pressure leaked past said second seal past said piston and into said second chamber of said fluid motor.   
     
     
       21. A valve and actuator assembly as recited in claim 15: said piston having a central vent receptacle;   said tubular stem drive element being received within said vent receptacle;   means establishing a seal between said piston and said tubular stem drive element and cooperating with said piston and tubular stem drive element to define a leakage vent chamber; and   a port defined in said piston and communicating said leakage vent chamber with said second chamber of said fluid motor.   
     
     
       22. A valve and actuator assembly as recited in claim 15: said fluid motor means having mechanical means for selectively preventing fluid actuation of said fluid motor means.   
     
     
       23. A valve and actuator assembly as recited in claim 15: said stem drive means threadedly engaging said valve stem and extending outwardly of said housing;   stop shoulder means being defined on said stem drive means; and   fluid motor lock-out means adapted to be interposed between said fluid motor means and said stop shoulder means to prevent fluid actuation of said fluid motor means.   
     
     
       24. A valve actuator assembly as recited in claim 23: said lock-out means comprising sleeve means disposed about said stem drive means;   lock-out bearing means being carried by said housing; and   said lock-out means being interposed between said lock-out bearing means and said stop shoulder means.   
     
     
       25. A valve and actuator assembly as recited in claim 15: said stem drive means comprising a rotatable element being disposed in threaded engagement with said valve stem means and extending through said top wall of said housing;   means defining an internal .Iadd.stop .Iaddend.shoulder on said housing; and   thrust shoulder means being carried by said stem drive means within said housing and being engageable with said internal stop shoulder to limit axial movement of said stem drive means in one direction.   
     
     
       26. A valve and actuator assembly as recited in claim 25: said thrust shoulder means being removable from said stem drive means to render said stem drive means inoperative.   
     
     
       27. A valve and actuator assembly as recited in claim 15: adjustable stop means being carried by said piston;   means facilitating adjustment of the position of said stop means relative to said piston; and   said stop means engaging a portion of said fluid motor to limit movement of said piston, said valve stem means and said gate means in one direction to positively align said flow port with said flow passage means.   
     
     
       28. A valve and actuator assembly as recited in claim 27: said means facilitating adjustment of said stop means comprising threads formed on said piston;   said stop means being disposed in threaded engagement with said threads of said piston; and   lock means carried by said stop means and being operative to lock said stop means relative to said piston.   
     
     
       29. A valve and actuator assembly as recited in claim 15: means defining a cushioning chamber within said housing; and   means being movable into said cushioning chamber upon movement of said piston under influence of said force imparting means and compressing a quantity of fluid within said cushioning chamber to dissipate energy imparted to said piston by said force imparting means thereby cushioning travel of said piston means at one extremity of travel of said piston means.   
     
     
       30. A valve and actuator assembly as recited in claim 29: said means defining a cushioning chamber comprising a cushioning recess defined in said top wall of said housing; and   said means being movable into said cushioning chamber being a thrust shoulder carried by said drive stem means and being received in close fitting relation within said cushioning recess.   
     
     
       31. A valve and actuator assembly as recited in claim 15: position indicator means being carried by said fluid motor means and being movable responsive to both fluid actuation or mechanical actuation of said valve stem to indicate the position of said gate means.   
     
     
       32. A valve and actuator assembly as recited in claim 31: said bottom wall of said housing having an aperture formed therein; and   said piston indicator means being an elongated member carried by said piston and extending through said aperture. .Iadd. 33. A valve and actuator assembly comprising:   valve body means defining a valve chamber and having flow passage means intercepting said valve chamber;   gate means being movably disposed within said valve chamber and having a flow port for registry with said flow passage means to conduct the flow of effluent through said valve and having a solid portion to block the flow of effluent;   bonnet means defining a closure for said valve chamber;   a fluid motor means attached to said bonnet means and having a housing defined by top and bottom walls and a generally cylindrical wall;   a piston being movably disposed within said housing and dividing said housing into first and second chambers;   means communicating pressurized actuating fluid into said first chamber to impart movement to said piston and said valve stem in one direction;   means venting said second chamber;   means imparting a force to said piston in a direction opposing said one direction;   valve stem means interconnecting said gate means and said piston;   stem drive means engaging said stem means and being operative to impart reciprocal movement to said stem means;   means defining an internal shoulder on said top wall of said housing;   thrust shoulder means being carried by said stem drive means within said housing and being engageable with said internal shoulder to limit axial movement of said stem drive means in one direction;   passageway means being defined in said piston to vent said actuating fluid from said first chamber into said second chamber; and   vent seal means being positionable in sealing relation between said stem drive means and said piston to block said passageway means and being positionable in non-sealing relation with said piston to open said   
     
     
        passageway means. .Iaddend..Iadd. 34.  A valve and actuator assembly as recited in claim 33 wherein: said stem drive means is a tubular stem drive element received about the outer extremity of said stem and being disposed in threaded engagement with said stem,   said stem drive means extending outwardly through said housing of said fluid motor means and having a dynamically sealed relationship with said housing of said fluid motor means. .Iaddend..Iadd. 35. A valve and actuator assembly as recited in claim 33, wherein   vent seal surface means is formed by said piston;   seal retainer means is provided on said stem drive means; and   said vent seal means is positively supported by said seal retainer means. .Iaddend..Iadd. 36. A valve and actuator assembly comprising:   valve body means defining a valve chamber and having flow passage means intercepting said valve chamber;   gate means being movably disposed within said valve chamber and having a flow port for registry with said flow passage means to conduct the flow of effluent through said valve and having a solid portion to block the flow of effluent;   bonnet means defining a closure for said valve chamber;   a fluid motor means attached to said bonnet means and having a housing defined by top and bottom walls and a generally cylindrical wall;   a piston being movably disposed within said housing and dividing said housing into first and second chambers;   means communicating pressurized actuating fluid into said first chamber to impart movement to said piston and said valve stem in one direction;   means venting said second chamber;   means imparting a force to said piston in a direction opposing said one direction;   valve stem means interconnecting said gate means and said piston, said valve stem cooperating with said body to define a first pressure responsive area of said stem;   stem drive means engaging said stem means and being operative to impart reciprocal movement to said stem means;   balancing means being provided for said stem means and cooperating with said stem drive means to define a second pressure responsive area of said stem means;   means communicating effluent pressure from said valve chamber to each of said pressure responsive areas of said valve stem means and causing pressure induced forces acting on said first and second pressure responsive areas of said stem means to be substantially balanced;   means defining an internal shoulder on said top wall of said housing;   thrust shoulder means being carried by said stem drive means within said housing and being engageable with said internal shoulder to limit axial movement of said stem drive means in one direction;   passageway means being defined in said piston to vent said actuating fluid from said first chamber into said second chamber; and   vent seal means being positionable in sealing relation between said stem drive means and said piston to block said passageway means and being positionable in non-sealing relation with said piston to open said   
     
     
        passageway means. .Iaddend..Iadd. 37.  A valve and actuator assembly as recited in claim 36 wherein: said stem drive means is a tubular stem drive element received about the outer extremity of said stem and being disposed in threaded engagement with said stem, said stem drive means extending outwardly through said housing of said fluid motor means and having a dynamically sealed relationship with said housing of said fluid motor means. .Iaddend.