초록 ▼

A pressure balanced gate valve mechanism wherein a closed loop fluid interchange system interconnects the valve actuator stem area of the valve mechanism with the pressure balancing stem area and functions to accomodate volumetric changes to prevent the development of a hydraulic lock that might oth

A pressure balanced gate valve mechanism wherein a closed loop fluid interchange system interconnects the valve actuator stem area of the valve mechanism with the pressure balancing stem area and functions to accomodate volumetric changes to prevent the development of a hydraulic lock that might otherwise prevent or retard opening and closing movement of the valve mechanism. Internal back-face seating arrangements with combination metal-to-metal and elastomeric sealing elements establish seals between the valve stem and bonnet at one gate position and between the pressure balancing stem and valve body structure at the opposite gate position. An externally threaded portion of the valve bonnet is receivable within internally threaded receiver openings of a plurality of different actuator systems, including manual, mechanical, hydraulic and pneumatic actuator systems. The actuator systems are field interchangeable with the valve in service and under pressure. The valve mechanism is capable of being hydraulically energized by portable hydraulic equipment for moving the valve mechanism to a predetermined position in the event the primary drive system should become inoperative for any reason.

대표청구항 ▼

A pressure balanced gate valve mechanism for controlling flow of fluid, said valve mechanism comprising: a valve body defining a valve chamber and inlet and outlet flow passages intersecting said valve chamber, said valve body being formed to define seat recess means within said valve chamber about

A pressure balanced gate valve mechanism for controlling flow of fluid, said valve mechanism comprising: a valve body defining a valve chamber and inlet and outlet flow passages intersecting said valve chamber, said valve body being formed to define seat recess means within said valve chamber about said inlet and outlet flow passages; seat carrier means being positioned within said valve chamber and being formed to define seat retainer means, said seat carrier means defining gate guide means; seat means being received by said seat retainer means of said seat carrier means and being at least partially received within said seat recess means; bonnet means forming a closure for said valve chamber and containing first packing means, said bonnet means defining stop and back-face surface means; gate means being movably positioned between said seat means and defining sealing surface means, said gate means defining port means for registry with said inlet and outlet passage means in the open position of said valve mechanism; manual operator means for moving said gate and including actuator stem means being extended through said bonnet and being sealed with respect to said bonnet by said first packing means, stop and back-face seal means being defined by said actuator stem means and being engageable with said stop and back-face surface means at one of the open and closed positions of said gate means; second packing means being supported by said valve body; a pair of pressure balancing stem means being connected to said gate means and extending at least partially through said valve body, said second packing means sealing said pressure balancing stem means with respect to said valve body said pressure balancing stem means are received within a pair of balancing chambers, said chambers are in fluid communication through a fluid line which is connected to a remote pressure source, at least one pressure balancing chamber being positioned at least partially within said actuator housing and outwardly of said first packing means, said one pressure balancing chamber is also formed within said operator, whereby the volume of fluid displaced by said pressure balancing stem means is equal and a balanced condition is mainained in each chamber during movement of said gate means; said valve body defining second stop and back-face seal surface means; and stop and back-face seal means being defined by said pressure balancing stem means and establishing sealing and gate positioning engagement with said second stop and back-face seal surface means in the other one of said open and closed positions of said gate means. A pressure balanced gate valve as recited in claim 1, wherein: packing retainer means is provided to retain said second packing within said valve, said packing retainer defining the other pressure balancing chamber, the other of said pressure balancing stem, means extending into said said other pressure balancing chamber seal means establishes a seal between said pressure balancing stem means and said packing retainer means; said operator means is adapted to impart reciprocal movement to said actuator stem, said operator means is capable of being rendered inoperative; and with said operator means rendered inoperative, force applied to said pressure balancing stem means in a direction toward said gate means imparts movement of said pressure balancing stem means and said gate means to a selected position thereof.