PSG Dover WILDEN PRO-FLO P.025, Engineering, Operation & Maintenance, Page: 6 / 28

WIL-10090-E-08
Wilden
®
6
The Wilden diaphragm pump is an air-operated, placement, 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 The air valve directs pressurized
air 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
separation
membrane between the
compressed air and liquid, balancing the
load and removing mechanical stress from
the diaphragm. The compressed air moves
the diaphragm away from the center block
of the pump. The opposite diaphragm is
pulled in by the shaft connected to the
pressurized diaphragm. Diaphragm B is on
its suction stroke; air behind the diaphragm
has been forced out to the atmosphere
through the exhaust port of the pump. The
movement of diaphragm B toward the
center block of the pump creates a vacuum
within chamber B. Atmospheric pressure
forces fluid into the inlet manifold forcing
the inlet valve ball off its seat. Liquid is free
to move past the inlet valve ball and fill the
liquid chamber (see shaded area).
FIGURE 2 When the pressurized
diaphragm, diaphragm A, reaches the limit
of its discharge stroke, the air valve
redirects pressurized air to the back side of
diaphragm B. The pressurized air forces
diaphragm B away from the center block
while pulling diaphragm A to the center
block. 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 mani-
fold of the pump. These same hydraulic
forces lift the discharge valve ball off 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 block of the pump creates a vacuum
within liquid chamber A. Atmospheric
pressure forces fluid into the inlet manifold
of the pump. The inlet valve ball is forced
off its seat allowing the fluid being pumped
to fill the liquid chamber.
FIGURE 3 At completion of the stroke,
the air valve again redirects air 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
exhaust and one discharge stroke. This
constitutes one complete pumping cycle.
The pump may take several cycles to
completely prime depending on the
conditions of the application.
HOW IT WORKS
— AIR DISTRIBUTION SYSTEM
The Pro-Flo
®
patented air distribution system incorporates
three moving parts: the air valve spool, the pilot spool, and the
main shaft/diaphragm assembly. The heart of the system is the
air valve spool and air valve. As shown in Figure 1, this valve
design incorporates an unbalanced spool. The smaller end of
the spool is pressurized continuously, while the large end is
alternately pressurized and exhausted to move the spool. The
spool directs pressurized air to one chamber while exhausting
the other. The air causes the main shaft/diaphragm assembly
to shift to one side
— discharging liquid on one side and pulling
liquid in on the other side. When the shaft reaches the end of
its stroke, it actuates the pilot spool, which pressurizes and
exhausts the large end of the air valve spool. The pump then
changes direction and the same process occurs in the
opposite direction, thus reciprocating the pump.
Section 3 HOW IT WORKS
— PUMP