dmf2dl5sm-rev0317
Model DMF2 Page 5
PRINCIPLE OF PUMP OPERATION
This flap swing valve pump is powered by compressed air and is a 1:1
pressure ratio design. It alternately pressurizes the inner side of one diaphragm
chamber, while simultaneously exhausting the other inner chamber. This
causes the diaphragms, which are connected by a common rod, to move
endwise. Air pressure is applied over the entire surface of the diaphragm,
while liquid is discharged from the opposite side. The diaphragm operates
under a balanced condition during the discharge stroke, which allows the unit
to be operated at discharge heads over 200 feet (61 meters) of water head.
Since the diaphragms are connected by a common rod, secured by plates
to the center of the diaphragms, one diaphragm performs the discharge stroke,
while the other is pulled to perform the suction stroke in the opposite chamber.
For maximum diaphragm life, keep the pump as close to the liquid being
pumped as possible. Positive suction head in excess of 10 feet of liquid (3.048 meters) may require a back pressure
regulating device. This will maximize diaphragm life.
Alternate pressuring and exhausting of the diaphragm chamber is performed by means of an externally mounted,
pilot operated, four-way spool type air distribution valve. When the spool shifts to one end of the valve body, inlet air
pressure is applied to one diaphragm chamber and the other diaphragm chamber exhausts. When the spool shifts to
the opposite end of the valve body, the porting of chambers is reversed. The air distribution valve spool is moved by
an internal pilot valve which alternately pressurizes one side of the air distribution valve spool, while exhausting the
other side. The pilot valve is shifted at each end of the diaphragm stroke by the diaphragm plate coming in contact
with the end of the pilot spool. This pushes it into position for shifting of the air distribution valve.
The chambers are manifolded together with a suction and discharge flap-type check valve for each chamber,
maintaining flow in one direction through the pump.
INSTALLATION & START-UP
Locate the pump as close to the product being pumped as possible, keeping suction line length and number of
fittings to a minimum. Do not reduce line size.
For installations of rigid piping, short flexible sections of hose should be installed between pump and piping. This reduces
vibration and strain to the piping system. A Warren Rupp Tranquilizer
®
surge suppressor is recommended to further reduce
pulsation in flow.
This pump was tested at the factory prior to shipment and is ready for operation. It is completely self-priming
from a dry start for suction lifts of 20 feet (6.096 meters) or less. For suction lifts exceeding 20 feet of liquid, fill the
chambers with liquid prior to priming.
AIR SUPPLY
Air supply pressures cannot exceed 125 psi (8.61 bar). Connect the pump air inlet to an air supply of sufficient capacity
and pressure required for desired performance. When the air line is solid piping, use a short length of flexible hose [not less
than 3/4" (19mm) in diameter] between pump and piping to eliminate strain to pipes.
Heavy Duty Flap
SERVICE AND OPERATING MANUAL
Model DMF2R
DMF2S
2" Flap Valve Pump
Type 5
II 2GD T5
See pages 20 & 21
for ATEX ratings
DR LLERS
S E R I E S
