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WILDEN PUMP & ENGINEERING, LLC
WIL-10220-E-02
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 pressur-
ized with air, while the opposite chamber is exhausted. When
electric power is applied, the solenoid shifts, and the pressur-
ized air chamber is exhausted while the opposite chamber is
pressurized. By alternately applying and removing 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 applica-
tions.
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.
SECTION 7D
INSTALLATION – A4 PLASTIC
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 38
mm (1-1/2") outlet and is designed for flow to 235 lpm (62
gpm). This maximum flow rate was calculated at 300 strokes
per minute with 100 psig air inlet against 0 psig discharge
head. The A4 Plastic pump is manufactured with wetted
parts of polypropylene or PVDF. The center section of the A4
Plastic pump is of aluminum or polypropylene 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 parameters.
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. WHEN-
EVER THE POSSIBILITY EXISTS THAT LARGER SOLID
OBJECTS MAY BE SUCKED INTO THE PUMP, A STRAINER
SHOULD BE USED ON THE SUCTION LINE.
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. See Section 10B for options
and part numbers.
