Search results
Results from the WOW.Com Content Network
An air-operated valve, also known as a pneumatic valve, is a type of power-operated pipe valve that uses air pressure to perform a function similar to a solenoid. As air pressure is increased, the compressed air starts to push against the piston or diaphragm walls which causes the valve to actuate.
The normally closed valves will not permit flow from the inlet port of the valve to the outlet port, normally the flow will be permitted only by changing the position of the valve. In general, valves are designated as 2/2 DCV, 3/2 DCV, 5/2 DCV, 5/3 DCV etc., in which the first number indicates number of ports and second number indicates number ...
Air (or other gas) pressure is the power source for pneumatic valve actuators. [1] They are used on linear or quarter-turn valves. Air pressure acts on a piston or bellows diaphragm creating linear force on a valve stem. Alternatively, a quarter-turn vane-type actuator produces torque to provide rotary motion to operate a quarter-turn valve.
These types of valves are also known as automatic control valves. The hydraulic actuators respond to changes of pressure or flow and will open/close the valve. Automatic control valves do not require an external power source, meaning that the fluid pressure is enough to open and close them.
Globe control valve with pneumatic diaphragm actuator and "smart" positioner which will also feed back to the controller the actual valve position. Taking the example of an air-operated valve, there are two control actions possible: "Air or current to open" – The flow restriction decreases with increased control signal value. "Air or current ...
Air pilot control: converting from air to oil results in locking of the cylinder. Shifting the four-way valve to either extreme position applies the air pilot through the shuttle valve, holding the two air-operated valves open and applying oil under air pressure to the corresponding side of the cylinder. Positioning a manual valve to neutral ...
Pneumatic non-return valves are used where a normal non-return valve would be ineffective. This is for example where there is a risk of flood water entering a site but an equal risk of pollution or a chemical spills leaving a site and polluting the environment.
A desmodromic valve is a reciprocating engine poppet valve that is positively closed by a cam and leverage system, rather than by a more conventional spring. The valves in a typical four-stroke engine allow the air/fuel mixture into the cylinder at the beginning of the cycle and exhaust spent gases at the end of the cycle. In a conventional ...