Gate valve having pressure balanced stem

Claim 2

A gate valve comprising: valve body means having flow passages defined therein and having a valve chamber disposed in intersecting relation with said flow passages; a gate valve element disposed within said valve chamber and having a flow port defined therein for registry with said flow passages in the open position of said valve and having a solid portion for blocking said flow passages in the closed position of said valve; bonnet means defining a closure for the upper extremity of said valve chamber; valve stem means being connected to said gate valve element and extending through said bonnet means; said valve stem means having a threaded portion; valve actuator means being fixed to said bonnet and having stem drive means threadedly received by said threaded portion of said valve stem in driving relative therewith; means for imparting movement to said gate valve element; and means communicating effluent pressure within said valve to the outer extremity of said valve stem means and controlling the direction and amount of resultant force developed by the effluent on the valve stem.

Claim 3

A gate valve as recited in claim 1: first packing means disposed within said bonnet and having an inside diameter establishing a dynamic seal about said valve stem means and encompassing a first cross-sectional area; said stem drive means defining a closed chamber about said valve stem means; second packing means being carried by said valve stem means and being received in dynamically sealed engagement within said stem drive means and encompassing a second cross-sectional area; and said effluent pressure acting simultaneously upon said first and second cross-sectional areas and developing said resultant force.

Claim 4

A gate valve as recited in claim 2: said first cross-sectional area being substantially equal to said second cross-sectional area and said resultant force being substantially zero.

Claim 5

A gate valve as recited in claim 2: said first cross-sectional area being greater than said second cross-sectional area and said resultant force urging said valve stem means outwardly away from said valve body.

Claim 6

A gate valve as recited in claim 2: said first cross-sectional area being less than said second cross-sectional area and said resultant force urging said valve stem means inwardly toward said valve body.

Claim 7

A gate valve as recited in claim 1: said means communicating effluent pressure within said valve to the outer extremity of said valve to the outer extremity of said valve stem comprising an effluent passage extending axially through said valve stem.

Claim 8

A gate valve as recited in claim 1: means defining a closed chamber outwardly of said valve stem; and fluid passage means formed in said valve stem means and communicating said effluent pressure into said closed chamber.

Claim 9

A gate valve as recited in claim 1: said valve stem means having a generally cylindrical surface; first packing means disposed within said bonnet and establishing a dynamically sealed relation with said cylindrical surface and encompassing a first cross-sectional area; second packing means carried by said valve stem means; said valve actuator means having a tubular drive sleeve being received about said valve stem and having an inner generally cylindrical surface disposed in dynamically sealed relation with said second packing means and encompassing a second cross-sectional area; means closing one extremity of said tubular drive sleeve and defining a closed chamber outwardly of said second packing means; means retaining said tubular drive sleeve in rotatable relation with said bonnet means; and said means communicating effluent pressure within said valve to the outer extremity of the valve stem means comprising passage means extending through said valve stem means.

Claim 10

A gate valve as recited in claim 8: said valve actuator means further comprising actuator adapter means being carried by said bonnet means; thrust flange means being carried by said tubular drive sleeve; and bearing means retained by said actuator adapter means and disposed in bearing engagement with said thrust flange means.

Claim 11

A gate valve as recited in claim 9: said thrust flange means comprising a flange retainer groove defined in said tubular drive sleeve; and at least two thrust flange segments being retained within said flange retainer groove by said actuator adapter means.

Claim 12

A gate valve as recited in claim 8: said tubular drive sleeve being disposed in threaded engagement with said valve stem and upon rotation thereof imparting reciprocal movement to said valve stem.

Claim 13

A gate valve as recited in claim 8: means establishing a lubricant chamber within said valve actuator means; and means causing flow of lubricant material within said lubricant chamber upon actuation of said valve and lubricating said valve actuator means.

Claim 14

A gate valve as recited in claim 8: said means closing one extremity of said tubular drive sleeve means comprising check valve means oriented to prevent escape of effluent pressure from said valve and allowing introduction of fluid into said valve.

Claim 15

A gate valve as recited in claim 1: means preventing communication of effluent pressure to the outer extremity of said valve means in at least one operating condition of said gate valve.

Claim 16

A gate valve as recited in claim 13: said means preventing communication of effluent pressure comprising an effluent seat surface formed within said bonnet; an effluent seat surface defined on said valve stem and being disposed in sealed relation with said effluent seat surface of said bonnet in said one operating condition; said means communicating effluent pressure within said valve to the outer extremity of the valve stem means being a passage extending through said valve stem means and terminating outwardly of said effluent seat surface of said valve stem; and said effluent seat surfaces of said bonnet and valve stem developing a seal in said one operating position and preventing fluid communication between said valve chamber and said passage of said valve stem means.

Claim 17

A gate valve comprising: valve body means having flow passaGes defined therein and having a valve chamber disposed in intersecting relation with said flow passages; a gate valve element disposed within said valve chamber and having a flow port defined therein for registry with said flow passages in the open position of said valve and having a solid portion blocking said flow passages in the closed position of said valve; bonnet means defining a closure for said valve chamber; valve stem means being connected to said gate valve element and extending through said bonnet means and being provided with a threaded portion; tubular stem drive means being disposed about the valve stem means and being disposed in threaded engagement therewith; means supporting said tubular drive means for rotation relative to said bonnet means; first packing means disposed within said bonnet and having an inside diameter establishing a dynamic seal about said valve stem means and encompassing a first cross-sectional area; second packing means being carried by said valve stem means and being received in dynamically sealed engagement within said tubular stem drive means and encompassing a second cross-sectional area; means communicating effluent pressure within said valve chamber outwardly of said second packing means; and said effluent pressure acting simultaneously upon said first and second cross-sectional areas and developing a resultant force acting on said valve stem means.

Claim 18

A gate valve comprising: valve body means having flow passaGes defined therein and having a valve chamber disposed in intersecting relation with said flow passages; a gate valve element disposed within said valve chamber and having a flow port defined therein for registry with said flow passages in the open position of said valve and having a solid portion blocking said flow passages in the closed position of said valve; bonnet means defining a closure for said valve chamber; valve stem means being connected to said gate valve element and extending through said bonnet means and being provided with a threaded portion; tubular stem drive means being disposed about the valve stem means and being disposed in threaded engagement therewith; means supporting said tubular drive means for rotation relative to said bonnet means; first packing means disposed within said bonnet and having an inside diameter establishing a dynamic seal about said valve stem means and encompassing a first cross-sectional area; second packing means being carried by said valve stem means and being received in dynamically sealed engagement within said tubular stem drive means and encompassing a second cross-sectional area; means communicating effluent pressure within said valve chamber outwardly of said second packing means; and said effluent pressure acting simultaneously upon said first and second cross-sectional areas and developing a resultant force acting on said valve stem means.

Claim 19

A gate valve as recited in claim 16: said first cross-sectional area being substantially equal to said second cross-sectional area and said resultant force being substantially zero.

Claim 20

A gate valve as recited in claim 16: said first and second cross-sectional areas being different and said resultant force urging said valve stem toward one extremity thereof.

Claim 21

A gate valve as recited in claim 16: means closing said tubular drive stem means at the outer extremity thereof; said second packing means cooperating with said tubular drive means to define a closed chamber outwardly of the second packing means; and said means communicating effluent pressure within said valve chamber outwardly of said second packing means being an effluent passage formed in said valve stem means and communicating effluent pressure into said closed chamber means.

Claim 22

A gate valve as recited in claim 19: means establishing a lubricant chamber within said valve actuator means; and means causing flow of lubricant material within said lubricant chamber upon actuation of said valve and lubricating said valve actuator means.

Claim 23

A gate valve as recited in claim 16: said tubular drive stem means having a thrust flange thereon; actuator adapter means being carried by said bonnet means and receiving said thrust flange of said tubular drive stem means; and thrust bearing means being received by said actuator adapter means and supporting thrust loading applied to said tubular drive stem means.

Claim 24

A gate valve as recited in claim 21: means preventing communication of effluent pressure outwardly of said second packing means in at least one operating condition of said gate valve.