Dover Wilden Advanced H38 Engenharia, exploração e manutenção - Página 5
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S e c t i o n 3
H O W I T W O R K S — P U M P
The Wilden piston 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.
CLOSED
B
A
OPEN
RIGHT STROKE
FIGURE 1: When air pressure is supplied to the
pump, the air valve directs pressure to the back
side of power piston A. The compressed air
moves the power/liquid piston A away from the
center section of the pump. At the same time,
air is directed to the front of power piston B by
means of tubing connected to the pressurized
air in side A. Power piston/liquid piston B is
on its suction stroke; air behind the piston has
been forced out to atmosphere through the
exhaust port of the pump. The movement of
power/liquid piston B toward the center section
of the pump creates a vacuum within chamber
B. Atmospheric pressure forces fluid into the
inlet port forcing the inlet valve ball, on side B,
off its seat. Liquid is then free to move past the
inlet valve ball and fill liquid chamber B (see
shaded area).
A I R D I S T R I B U T I O N S Y S T E M — H O W I T W O R K S
WIL-11181-E-04
OPEN
OPEN
B
CLOSED
CLOSED
LEFT STROKE
FIGURE 2: When piston A reaches the limit of its
discharge stroke, the air valve redirects pressur-
ized air to the back side of the power/liquid piston
B and the front side of power/liquid piston A. The
pressurized air forces power/liquid piston B away
from the center section while pressurized air forces
power/liquid piston A toward the center section.
Power/liquid piston B is now on its discharge
stroke. Liquid piston B forces the inlet valve ball,
on side B, onto its seat due to the hydraulic forces
developed within the liquid chamber. 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 combined force created
by both power pistons being pressurized and the
smaller size of the liquid piston area relative to the
total area of the power piston creates the ampli-
fied liquid discharge pressure. The movement of
power/liquid piston A toward the center section of
the pump creates a vacuum within liquid chamber
A. Atmospheric pressure forces fluid into the inlet
port. The inlet valve ball, on side B, is forced off its
seat allowing the fluid being pumped to fill liquid
chamber A.
The Pro-Flo
three moving parts: the air valve spool, the pilot spool, and the
main shaft/piston assembly. The heart of the system is the air
valve spool and air valve. As shown in this figure, this valve
design incorporates an unbalanced spool. The smaller end of
the spool is pressurized continuously, while the large end is
alternately pressurized then exhausted to move the spool. The
spool directs pressurized air to one air chamber while exhaust-
ing the other. The air causes the main shaft/piston assembly to
shift to one side — discharging liquid on that side and pulling
liquid in on the other side. When the shaft reaches the end of its
stroke, the power piston actuates the pilot spool, which pres-
surizes and exhausts the large end of the air valve spool. The
repositioning of the air valve spool routes the air to the other
air chamber.
3
CLOSED
CLOSED
B
A
OPEN
OPEN
RIGHT STROKE
FIGURE 3: At completion of the stroke, the air
valve again redirects air to the back side of
power/liquid piston A, which starts power/liq-
uid piston B on its suction stroke. As the pump
reaches its original starting point, each power/
liquid piston has gone through one suction
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.
patented air distribution system incorporates
®
WILDEN PUMP & ENGINEERING, LLC
OPEN
A
CLOSED