3
WILDEN PUMP & ENGINEERING, LLC
WIL-10070-E-03
SECTION 3
THE WILDEN PUMP — HOW IT WORKS
The Wilden diaphragm pump is an air-operated, positive displacement, self-priming pump. These drawings show the flow
pattern through the pump upon its initial stroke. It is assumed the pump has no fluid in it prior to its initial stroke.
FIGURE 1 When the solenoid is ener-
gized, the air valve directs pressure
to the back side of diaphragm A. The
compressed air is applied directly to the
liquid column separated by elastomeric
diaphragms. The diaphragm acts as
a membrane between the compressed
air and the liquid, balancing the load
and removing mechanical stress from
the diaphragm. The compressed
air moves the diaphragm away from
the center section of the pump. The
opposite diaphragm is pulled in by
the shaft connected to the pressur-
ized diaphragm. Diaphragm B is on its
suction stroke; air behind the diaphragm
has been forced out to the atmosphere
through the exhaust port. The move-
ment of diaphragm B toward the center
section of the pump creates a vacuum
within chamber B. Atmospheric pres-
sure forces fluid into the inlet manifold
forcing the inlet valve ball off of its seat.
Liquid is free to move past the inlet
valve ball and fill the liquid chamber (see
shaded area).
FIGURE 2 When the solenoid valve is
deenergized, the air valve redirects pres-
surized air to the back side of diaphragm
B. The pressurized air forces diaphragm
B away from the center section while
pulling diaphragm A to the center
section. Diaphragm B is now on its
discharge stroke. Diaphragm B forces
the inlet valve ball onto its seat due
to the hydraulic forces developed in
the liquid chamber and manifold of the
pump. These same hydraulic forces lift
the discharge valve ball off of its seat,
while the opposite discharge valve ball
is forced onto its seat, forcing fluid to
flow through the pump discharge. The
movement of diaphragm A toward the
center section of the pump creates a
vacuum within liquid chamber A. Atmo-
spheric pressure forces fluid into the
inlet manifold of the pump. The inlet
valve ball is forced off of its seat allowing
the fluid being pumped to fill the liquid
chamber.
FIGURE 3 Once the solenoid valve is
reenergized, the air is directed to the
back side of diaphragm A, which starts
diaphragm B on its exhaust stroke. As
the pump reaches its original starting
point, each diaphragm has gone through
one intake and one discharge stroke.
This constitutes one complete pump-
ing cycle. The pump may take several
cycles to completely prime depending
on the conditions of the application.
RIGHT STROKE
LEFT STROKE
RIGHT STROKE
