A limit switch for a rising-stem type valve which has a spring-loaded actuator arm with a bracket on one end which wraps around the valve stem. A follower or roller on the end of the bracket opposite the actuator arm rides on the rising stem of the valve, held in contact with the stem by the spring. When the stem has risen to a preselected position, usually the position in which the valve is fully open, the follower or roller engages a circumferential groove formed around the stem. This causes the spring to bias the actuator arm to move a tab at the opposite end of the actuator arm, and the tab operates a limit switch.

A limit switch for a rising-stem type valve which has a spring-loaded actuator arm with a bracket on one end which wraps around the valve stem. A follower or roller on the end of the bracket opposite the actuator arm rides on the rising stem of the valve, held in contact with the stem by the spring. When the stem has risen to a preselected position, usually the position in which the valve is fully open, the follower or roller engages a circumferential groove formed around the stem. This causes the spring to bias the actuator arm to move a tab at the opposite end of the actuator arm, and the tab operates a limit switch.

A fully-dense, fluid tight, low friction coating system is described that is characterized by fluid impermeability and a reduced coefficient of friction. The coating system includes a fully dense, fluid tight underlying layer; and a low friction layer. Unlike conventional materials requiring a sealant, the coating systems of the present invention achieves better fluid tightness and maintains said fluid tightness along one or more sealing surfaces at higher service temperatures and service pressures than previously attainable. The constituents of the fully-dense, fluid tight, low friction coating system are physically and chemically compatible so as to not adversely impact lubricity, wear resistance and corrosion resistance during the service life of a component coated with the fully-dense, fluid tight, low friction coating system.

A grease-retaining frac valve insert to mitigate grease loss during operation of a frac valve, a frac valve assembly using one or more of the grease-retaining frac valve insert, and a wellhead including one or more frac valve assemblies using one or more of the grease-retaining frac valve inserts. The frac valve assembly includes a valve gate defining a valve aperture movable from an wellhead operating position to the valve open position. The grease-retaining frac valve insert includes a seal plate defining a cuff receptacle. A valve sealing cuff is removably received in the cuff receptacle. The valve sealing cuff carries a face sealing groove for sealing against the valve aperture as the valve gate is moved between the wellhead operating position to the valve open position.

A hydraulic cartridge valve includes a movable member and a position monitoring mechanism configured to detect the position of the movable member. The position monitoring mechanism is adapted to generate a position signal indicative of the position of the movable member. The position monitoring mechanism can be in the form of a linear variable differential transformer (LVDT).

A hydraulic cartridge valve includes a movable member and a position monitoring mechanism configured to detect the position of the movable member. The position monitoring mechanism is adapted to generate a position signal indicative of the position of the movable member. The position monitoring mechanism can be in the form of a linear variable differential transformer (LVDT).

A push joint adapter is connectable to one or more push joint pipe fittings in a pipeline. The push joint adapter includes an insertion section insertable into a socket of a push joint pipe fitting in an interference fit, a pipeline section connectable with the pipeline, and a collar disposed between the insertion section and the pipeline section. A restraint ring assembly cooperable with the push joint pipe fitting includes a restraint ring secured to the pipeline section and engaging the collar and a restraint rod connected to the restraint ring. The push joint adapter facilitates connecting push joint gasketed bell gate valves and fittings in a pipeline such as a polyethylene pipeline.

A device for controlling feed of fluid to equipment, such as a heat exchanger, the device including: a fluid slide valve mounted in a fluid circuit including a slide movable between two positions, a first position in which it allows the fluid to flow through the equipment, and a second position in which it prevents the fluid from flowing through the equipment; a laminar flow constriction arranged in the fluid circuit upstream from the slide valve; and a drive mechanism moving the slide of the slide valve between its two positions by head loss of the fluid in the laminar flow constriction.

A device for controlling feed of fluid to equipment, such as a heat exchanger, the device including: a fluid slide valve mounted in a fluid circuit including a slide movable between two positions, a first position in which it allows the fluid to flow through the equipment, and a second position in which it prevents the fluid from flowing through the equipment; a laminar flow constriction arranged in the fluid circuit upstream from the slide valve; and a drive mechanism moving the slide of the slide valve between its two positions by head loss of the fluid in the laminar flow constriction.

A bypass plunger combines a unitary or one-piece hollow body-and-valve cage, retains a dart valve within the valve cage portion of the hollow body using a threaded retaining nut secured by crimple detents. A series of helical grooves surround the central portion of the outer surface of the hollow body of the plunger to control spin during descent. A canted-coil-spring disposed within the retaining nut functions as a clutch. The valve cage includes ports that may be configured to control flow through the plunger during ascent. Other embodiments include clutch assemblies using canted-coil springs with split bobbins, and valve stems surfaced to achieve specific functions. Combinations of these features provide enhanced performance, durability and reliability at reduced manufacturing cost, due primarily to the simplicity of its design.