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An angle seat piston valve is a
pneumatically-controlled valve with a piston
actuator providing linear actuation to lift a seal
off its seat. The seat is set at an angle to provide
the maximum possible flow when unseated. Angle seat
piston valves are particularly suited to
applications where high temperatures and large
flowrates are required, such as steam or water. When
used in reverse some models of angle seat piston
valve will eliminate water hammer when operated.
Operation
Pneumatic valves are operated by a pilot medium
under pressure, usually compressed air but also oil
or water.
The valve is equipped with a pneumatic actuator
supplied by a three-way solenoid valve. The pressure
of the pilot medium enters the actuator cylinder and
acts on the piston, which allows the seal to open or
to close through the stem. The return of the seal
into its rest position is usually achieved by a
return spring that can be found in the pneumatic
actuator.
In the double acting configuration there is no
return spring and the pilot medium is used both for
opening and for closing the valve.
A red indicator becomes visible through the sight
dome that is found on the top of the actuator when
the valve is in the open position.
The pressure range depends on the pressure of the
pilot medium and the controlled medium and on the
direction of the flow, but also on construction
parameters of the valve, such as the diameter of the
orifice, the diameter of the actuator cylinder and
the spring force. |
