pneumatically actuated valves-control valves
Control valves are typically operated with instrument air and are therefore characterised as pneumatically actuated valves. Electric and electro-hydraulic actuators can also be used with control valves. However, they are generally more complicated and thus more expensive compared with pneumatic actuators. They offer advantages where no instrument air or instrument gas supply source is available, in low ambient temperatures in which condensed water in pneumatic supply lines could freeze, or where unusually large driving (stem) forces are necessary for valve movement. Pneumatic type control valves are typically globe valves.
Control valves are typically designed to operate in a closed loop, i.e. information regarding the process variable is continuously fed back to the controller set point in order to provide continuous, automatic corrections to the process variable. This is usually referred to as the feedback loop.
More products of valves
2012-08-08
