Control valve accessories are various, some are very vital for the performance of the whole machine. Positioners are chief accessories. Pneumatically operated valves rely upon a positioner to take a input from a process controller and convert it into valve traveling. Solenoid valve manifold is likewise an crucial kind of control valve accessory. The actuator type as well as the desired fail safe operation determine the selection of the suitable solenoid valve.
Limit switches also have close relationship KP-LOK with valves. Even the cam-operated type is typically used using 2 to four separate switches run by movement of the valve stem. An assembly which mounts on the face of the actuator houses the switches. Each switch adjusts independently and could be supplied for alternating current or direct current programs. Other forms of valve-mounted limit switches can also be offered.
Supply pressure regulators commonly called airsets, which can reduce plant air distribution to valve positioners and other control equipment. The regulator mounts integrally to the positioner or nipple-mounts or bolts into the actuator.
Pneumatic lock up systems are traditionally used with control detectors to lock in existing actuator loading pressure at the eventuality of supply pressure collapse. They can be used in combination with volume tanks to go the valve to the open or closed position on loss of pneumatic air distribution. Normal operation resumes mechanically with restored supply pressure. Functionally similar structures are offered for control valves using diaphragm actuators.
Electro-pneumatic transducer KP-LOK Bellows Valves receives a direct current input signal and uses a torque motor, nozzle-flapper, and biometric relay to convert the electric signal into a proportional pneumatic output . Nozzle pressure functions the relay and is piped into the torque engine responses bellows to supply a comparison between input and nozzle pressure. As shown, the transducer can be mounted on a control valve and operate the valve without the need for additional boosters or positioners. And the electro-pneumatic positioners can be found in electric controller loops to use pneumatic diaphragm control valve actuators.