SANDPIPER ST40 - Manual (Page 6)

st15dl4sm-rev0614 Models ST1½, ST40 Page 4
PLEASE NOTE!
The photos shown in this manual are for general instruction only. Your specific model
may not be shown. Always refer to the parts list and exploded view drawing for your
specific model when installing, disassembling or servicing your pump.
PRINCIPLE OF OPERATION
All Warren Rupp SANDPlPER pumps, including this Containment Duty SANDPlPER
pump, operate on the same basic principle. They are designed to be powered by compressed
air only which alternately pressurizes the inner side of one diaphragm chamber while
simultaneously exhausting the other inner chamber. The diaphragms are connected by
a common rod; when the inner side of one diaphragm chamber is pressurized, moving
the diaphragm outward on a discharge stroke, the opposite diaphragm is pulled inward
on a suction stroke.
Alternate pressurizing and exhausting of the diaphragm chamber is accomplished
with an externally mounted pilot operated, four way, spool type, air distribution valve.
When the spool is at one end of the valve body, inlet air pressure is connected to one
diaphragm chamber while the other diaphragm chamber is exhausting. When the spool
is moved to the opposite end of the valve body, the porting of chambers is reversed. The
air distribution valve spool is moved from one end position to the other in the valve body
by an internal pilot valve which alternately pressurizes one end of the air distribution valve
spool while simultaneously exhausting the other. The pilot valve is positively shifted at
each end of the diaphragm stroke by the diaphragm plate contacting the end of the pilot
valve spool. This pushes it into position to shift the air distribution valve.
In all SANDPlPER pumps, this reciprocating diaphragm movement creates an alternating
suction and discharge action in the outer diaphragm chamber and the pumped material. A
manifold with a suction and discharge check valve for each chamber serves as a common
inlet and outlet for the pump.
This Containment Duty SANDPlPER unit differs from other SANDPIPER units only in
that it utilizes four (4) diaphragms instead of two (2). Two rod-connected diaphragms are
the driver diaphragms. The other two (outermost) diaphragms are the actual pumping
diaphragms. Each driver diaphragm (of neoprene or other elastomer), and the pumping
diaphragm (of PTFE), are separated by a chamber filled with liquid which transmits the
reciprocating motion of the driver diaphragm to the pumping diaphragm. The PTFE pumping
diaphragms, in turn, create the alternating suction and discharge action in the outer
diaphragm chambers, and are the only diaphragms in contact with liquid being pumped.
INSTALLATION PROCEDURES
CAUTION: This pump should not be applied in pumping applications where the driver
liquid coming in contact with the pumped liquid would create a hazardous condition.
This contact will occur if a PTFE pumping diaphragm fails since this diaphragm normally
separates the two liquids. Also note that care must be taken to guard against the operation
of this unit if it has been subjected to freezing temperatures. If the driver liquid freezes,
possible diaphragm failure may result.
Locate pump as close to product to be pumped as is practical to keep length of suction
line and number of fittings to a minimum. DO NOT REDUCE SUCTION LINE SIZE except
for very low flow rates or where higher velocities are required to keep pumped material
in suspension in the carrying liquid.
This unit is completely self-priming from a dry start up to a static suction lift of 10
feet (3.05 meters). For priming at suction lifts in excess of 10 feet (3.05 meters), fill the
pumping chambers with liquid prior to operation. POSITIVE SUCTION HEAD IN EXCESS
OF 10 FEET (3.05 METERS) OF LIQUID SHOULD ALSO BE AVOIDED FOR BEST
DIAPHRAGM SERVICE LIFE.
Model ST1½ Type 4
Model ST40 Type 4
SERVICE & OPERATING MANUAL
Original Instructions
II 2GD T5
See pages 18 & 19
for ATEX ratings