Abstract: A gate valve is disclosed which comprises a valve body which includes a flow bore that extends completely therethrough and a gate cavity that extends partially therethrough and intersects the flow bore, a bonnet which is connected to the valve body over the gate cavity, a gate which is disposed in the gate cavity across the flow bore and includes a transverse opening that extends completely therethrough, a valve stem which includes a first portion that is connected to the gate and a second portion that extends through the gate cavity, a handwheel, and a roller screw assembly which is connected between the handwheel and the second portion of the valve stem and which converts rotation of the handwheel into translation of the valve stem. In this manner, translation of the valve stem raises or lowers the gate to bring the opening into or out of alignment with the flow bore to either open or close the gate valve, respectively.

Abstract: A gate valve is disclosed which comprises a valve body which includes a flow bore that extends completely therethrough and a gate cavity that extends partially therethrough and intersects the flow bore, a bonnet which is connected to the valve body over the gate cavity, a gate which is disposed in the gate cavity across the flow bore and includes a transverse opening that extends completely therethrough, a valve stem which includes a first portion that is connected to the gate and a second portion that extends through the gate cavity, a handwheel, and a roller screw assembly which is connected between the handwheel and the second portion of the valve stem and which converts rotation of the handwheel into translation of the valve stem. In this manner, translation of the valve stem raises or lowers the gate to bring the opening into or out of alignment with the flow bore to either open or close the gate valve, respectively.

Abstract: A sucker rod coupling 10 having a high ultimate tensile strength, resistance to corrosion, and resistance to surface cracking arising out of a method of making the sucker rod coupling 10, which employs a five-step process of forming a coupling 10. First, a hollow cylindrical core 12 from a heat treatable steel is formed. Second, a thin coating 18 of metallic alloy is applied to the outer surface of the core 12. Third, the core 12 is heat treated. Fourth, threads 20 are partially cut in the inner surface of the core 12. Fifth, the threads 20 are cold worked to transform the partially cut threads 20 into finished threads 20 and to place the thread roots 22 in compression.

Abstract: A sucker rod coupling 10 having a high ultimate tensile strength, resistance to corrosion, and resistance to surface cracking arising out of a method of making the sucker rod coupling 10, which employs a five-step process of forming a coupling 10. First, a hollow cylindrical core 12 from a heat treatable steel is formed. Second, a thin coating 18 of metallic alloy is applied to the outer surface of the core 12. Third, the core 12 is heat treated. Fourth, threads 20 are partially cut in the inner surface of the core 12. Fifth, the threads 20 are cold worked to transform the partially cut threads 20 into finished threads 20 and to place the thread roots 22 in compression.

Abstract: A sucker rod coupling 10 having a high ultimate tensile strength, resistance to corrosion, and resistance to surface cracking arising out of a method of making the sucker rod coupling 10, which employs a five-step process of forming a coupling 10. First, a hollow cylindrical core 12 from a heat treatable steel is formed. Second, a thin coating 18 of metallic alloy is applied to the outer surface of the core 12. Third, the core 12 is heat treated. Fourth, threads 20 are partially cut in the inner surface of the core 12. Fifth, the threads 20 are cold worked to transform the partially cut threads 20 into finished threads 20 and to place the thread roots 22 in compression.

Abstract: An electro-pneumatic or electro-hydraulic safety system for shutting in a well or the like in the event of unusual pressure conditions in the production line of the well. The safety system includes a pressure transducer (30) which senses the flowline pressure and provides a corresponding electrical signal to a digital controller (34). When the signal applied to the controller is outside of a preset range defined between low and high settings of the controller, a control circuit deenergizes a solenoid valve which bleeds fluid from a fluid actuator in order to close a surface safety valve (10). Once the safety valve has closed, the controller is latched out of service and must be manually reset before the safety valve can be opened. For protection of a subsurface safety valve (155), the safety system provides a time delay between opening of the subsurface valve and opening of the surface valve and also between closing of the surface valve and closing of the subsurface valve.