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WILDEN PUMP & ENGINEERING, LLC
WIL-10260-E-02
SECTION 7D
INSTALLATION – A4 METAL
ACCU-FLO™ PUMPS
Before installing your A4 Accu-Flo™ pump, review Section
7A for general installation suggestions including Location,
Access, Air Supply, Elevation, and Piping.
The Accu-Flo™ Model A4 has a 38 mm (1-1/2") inlet and
32 mm (1-1/4") outlet and is designed for flows to 196 lpm
(52 gpm). This maximum flow rate was calculated at 200
strokes per minute with 8.3 bar (120 psig) air inlet against 0
bar (0 psig) discharge head. The A4 Metal pump is manu-
factured with wetted parts of polypropylene or PVDF. The
center section of the A4 Metal pump is of aluminum or poly-
propylene construction. A variety of diaphragms, valve balls,
and o-rings are available to satisfy temperature, chemical
compatibility, abrasion and flex concerns.
All wiring used to operate the pump should be placed and
connected according to the proper electrical codes. It is
important that the wiring is of adequate gauge to carry
the current required to operate the pump. In addition, it is
necessary that the electrical power supply is large enough
to supply the current required to operate the pump. Wiring
should be above ground level if possible (in case of fluid
spill or leakage), and all wiring and connections which could
become wet or damp should be made watertight.
If the pump is to be used in a self-priming application, be
sure that all connections are airtight and that the suction lift
is within the pump’s ability. Note: Materials of construction
and elastomer material have an effect on suction lift param-
eters. Please refer to pump performance data.
Pumps in service with a positive suction head are most effi-
cient when inlet pressure is limited to 0.5–0.7 bar (7–10 psig).
Premature diaphragm failure may occur if positive suction
head is 0.8 bar (11 psig) and higher.
The solenoid valve is rated for continuous duty; however,
stopping on an even number stroke count insures that the
electrical power is off when pump is stopped. This practice is
safer and also eliminates unwanted strokes when the system
is shut down and electrical power is off.
THE MODEL A4 WILL PASS 4.8 mm (3/16") SOLIDS. THE M4
STALLION WILL PASS 13 mm (1/2") SOLIDS. WHENEVER
THE POSSIBILITY EXISTS THAT LARGER SOLID OBJECTS
MAY BE SUCKED INTO THE PUMP, A STRAINER SHOULD
BE USED ON THE SUCTION LINE.
SECTION 7C
OPERATING PRINCIPLES BEHIND
ACCU-FLO™ PUMPS
In Accu-Flo™ pump models, the standard air valve is replaced
with a two position, four-way solenoid valve that has a single
operator and spring return. The valve is internally air piloted
for longer coil and operator life.
When the solenoid is unpowered, one air chamber is pres-
surized with air, while the opposite chamber is exhausted.
When electric power is applied, the solenoid shifts, and the
pressurized air chamber is exhausted while the opposite
chamber is pressurized. By alternately applying and remov-
ing power, the solenoid-operated pump runs like a standard
Wilden pump.
The speed of the pump is controlled electrically. Since each
stroke is controlled by an electrical signal, the pump is ideal
for batching and other electrically controlled dispensing appli-
cations.
Although the speed of the pump is controlled electrically,
the air pressure is important. Air pressure displaces the fluid,
and if the pressure is insufficient to complete the physical
stroke before an electronic impulse signals the pump to shift,
the stroke will not be completed, and the displacement per
stroke will be reduced. This does not harm the unit in any
way, but it may cause inaccuracy when attempting to batch
specific quantities with high precision if this effect is not
taken into account.
There are three coil voltage options available. One coil allows
for 24V DC operation. The second coil option allows for
operation with either 12V DC or 24V AC at 60 Hz and the third
coil option allows for 110V AC operation.
WARNING: Before installation, consult chart in Section
10B to ensure proper electrical connection.
WARNING: The solenoid valve should not be used in
an area where explosion proof equipment is required
unless NEMA 7 valve is specified.
There are three coil options available in both NEMA 4 and
NEMA 7 ratings. One coil allows for 110V AC operation, one
allows for 24V DC operation, and the third allows for either
24V AC or 12V DC operation. Consult Section 10C for refer-
ence and part numbers.
