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Home -> Solenoid Valves
The principal of a 2/2 Pilot Operated Solenoid Valve
Pilot operated solenoid valves consist of two chambers, separated by the diaphragm
which is not directly coupled to the core (sometimes called indirect acting).
The upper chamber is connected to upstream through a compensation hole or pilot
hole in either the cover or diaphragm. The pressure of the media is acting
on the upper side of the diaphragm, the keeping the valve closed. When the
coil is energised the core lifts off the orifice seat allowing the operating
chamber to de-pressurise. In this condition the thrust of the upstream pressure
under the diaphragm prevails and the diaphragm lifts, thus opening the valve.
The principal is very similar in the case of normally open valves however normally
open operators are used. Pilot operated solenoid valves can operate only with
a suitable upstream pressure differential therefore they do not operate at
zero pressure. In addition, a minimum pressure differential across the valve
is required to keep them open or closed. Pilot operated solenoid valves can
provide high flow rates at high pressures with a lower power consumption.
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| fig 1 - 2/2 Pilot Operating |
fig 2 - 2/2 Pilot Operating |
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