Operating instructions

34
Mechanical and electrical design
55
56
0306
0307
Supply injection valve
Construction
The valve has a single-inlet with either one, two
or three outlets, each with its own solenoid coil.
The body is made of heat-resistant polyamid
plastic and the solenoids encased in water-tight
plastic. The electrical connector terminals are
spade lugs.
A filter screen on the inlet side prevents dirt from
entering the valve. Flow restrictors can be
placed at either the inlet or any of the outlets.
Operation
When the solenoid is energized, the spring-
loaded plunger is drawn up and the pilot valve in
the centre of the diaphragm open. Because of
the difference in diameter between the pilot
valve opening and the ventilating hole in the
diaphragm, the pressure above the diaphragm
drops to a point where the admission pressure
below the diaphragm can lift the diaphragm, thus
opening the valve.
When the current to the solenoid is cut off, the
plunger spring will press the plunger against the
pilot opening of the diaphragm. The pressure
above the diaphragm then rises to correspond to
the water inlet pressure and the pressure of the
spring will close the valve.
Fig.
55
Fig.
56