SANDPIPER ST25A User Manual

II 2GD T5

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SERVICE AND OPERATING MANUAL

Model ST1-A

Model ST25A

Type 4

PRINCIPLE OF OPERATION

This ball check 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

before installation and start-up of the pump.
It is the responsibility of the purchaser to
retain this manual for reference. Failure to
comply with the recommendations stated
in this manual will damage the pump, and
void factory warranty.

IMPORTANT

Rea d th ese saf ety
w a r n i n g s a n d
in struc ti ons in th is
manual completely,

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

Re-torque loose fasten ers to prevent
leakage. Follow recommended torques
stated in this manual.

CAUTION

B e f o r e p u m p
operation, inspect all
gasketed fastene rs
for looseness caused
by gasket creep.

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 valve spool. This pushes it into position for shifting of
the air distribution valve.

The chambers are manifolded together with a suction and discharge check valve for
each chamber, maintaining ow in one direction through the pump.

This specially-tted SandPIPER pump differs from standard units in that it utilizes
four diaphragms instead of two. The two rod-connected diaphragms being the driver
diaphragms, and the other two (outermost) diaphragms being the actual
pumping diaphragms. Each driver diaphragm (of Neoprene or other elastomer), and the

The discharge line may be pressurized
and must be bled of its pressure.

WARNING

Before maintenance
or repair, shut off the
com-pressed air line,
bleed the pressure,
and disconnect the
air line from the pump.

pumping diaphragm (of TFE), are separated by a chamber lled with liquid. This
transmits the reciprocating motion of the driver diaphragm to the pumping diaphragm.
The TFE pumping diaphragms create alternating suction and discharge action to each
outer diaphragm chamber. The pumping diaphragms are the only ones in contact with
the liquid being pumped.

INSTALLATION & START-UP

Locate the pump as close to the product being pumped as possible, keeping suction
line length and number of ttings to a minimum. Do not reduce line size.

For installations of rigid piping, short exible sections of hose should be installed

discharged into the atmosphere. The air
exhaust must be piped to an appropriate
area for safe disposition.

WARNING

I n t h e e v e nt o f
diaphragm rupture,
pumped material may
enter the air end of
th e pump , and be

between pump and piping. This reduces vibration and strain to the piping system.
A Warren Rupp Tranquilizer
pulsation in ow.

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 10-15 feet (35 meters) or
less. For suction lifts exceeding 15 feet of liquid, ll the chambers with liquid prior to
priming.

AIR SUPPLY

Air supply pressures cannot exceed 125 psi (8.61 bar). Connect the pump air inlet

®

surge suppressor is recommended to further reduce

WARNING

Take action to prevent
stati c sparking. Fire
or e xpl os ion can
res ul t, es pe cia l ly
w h e n h a n d l i n g

flammable liquids.
The pump, piping, valves,
co nta in er s or othe r m is ce lla ne ous
equipment must be grounded.

to an air supply of sufcient capacity and pressure required for desired performance.
When the air line is solid piping, use a short length of exible hose (not less than 3/4"
[19mm] in diameter) between pump and piping to eliminate strain to pipes. Use of a
Warren Rupp Filter/Regulator in the air line is recommended.

WARREN RUPP, INC. A Unit of IDEX Corporation • P.O. Box 1568 • Manseld, Ohio 44901-1568 USA • [phone] Fax [phone]

520-005-000 1/04

Models ST1-A, ST25A Type 4 Page 1

AIR INLET & PRIMING

For start-up, open an air valve approximately 1/2" to 3/4" turn. After the unit primes,
an air valve can be opened to increase ow as desired. If opening the valve increases
cycling rate, but does not increase ow rate, cavitation has occurred, and the valve
should be closed slightly.

For the most efcient use of compressed air and the longest diaphragm life, throttle
the air inlet to the lowest cycling rate that does not reduce ow.

WARNING

Do not sm oke near
t he p ump o r u s e
th e pu mp ne a r a n
ope n flam e. Fire or
explosion could result.

AIR EXHAUST

If a diaphragm fails, the pumped liquid or fumes can enter the air end of the pump,
and be exhausted into the atmosphere. When pumping hazardous or toxic materials,
pipe the exhaust to an appropriate area for safe disposition.

This pump can be submerged if materials of construction are compatible with the
liquid. The air exhaust must be piped above the liquid level. Piping used for the air
exhaust must not be smaller than 1" (2.54 cm). Reducing the pipe size will restrict air
ow and reduce pump performance. When the product source is at a higher level than
the pump (ooded suction), pipe the exhaust higher than the product source to prevent
siphoning spills.

Freezing or icing of the air exhaust can occur under certain temperature and humidity
conditions. Use of an air dryer should eliminate most icing problems.

BETWEEN USES

When used for materials that tend to settle out or transform to solid form, the pump
should be completely ushed after each use, to prevent damage. Product remaining
in the pump between uses could dry out or settle out. This could cause problems with
valves and diaphragms at re-start. In freezing temperatures, the pump must be drained
between uses in all cases.

CHECK VALVE SERVICING

Need for inspection or service is usually indicated by poor priming, unstable cycling,
reduced performance or the pump’s cycling but not pumping. (See Fig. 3)

Inspect the surfaces of both check valve and seat for wear or damage that could
prevent proper sealing. If pump is to prime properly, valves must seat air tight.

DIAPHRAGM SERVICING

Driver Diaphragms:

Drain the intermediate diaphragm housing (Item 36) by removing the pipe plug
directly beneath and behind the mounting ange. This port is also used for the optional
Electronic Leak Detector (Warren Rupp p/n 032-017-000 115 volt or p/n 032-018-000
220 volt). Remove four bolts securing the manifold ange to the chamber. Remove eight
nuts (Item 42) securing the inner diaphragm chamber (Item 22) and remove the outer
driver diaphragm assembly by pulling it axially off the studs. This permits inspection of
the Virgin PTFE diaphragm and the driver diaphragm. Pumping diaphragm chambers
need not be separated for access to the driver diaphragm. Loosen the plate which
secures the diaphragm and plate to the rod by keeping the diaphragm engaged with
the inner diaphragm chamber (Item 22) by inserting two or three capscrews through the
bolt holes so that the diaphragm cannot rotate when loosening. The diaphragm plates,
diaphragm and bumper will now come off the assembly. Repeat all actions if the other
diaphragm needs to be inspected or replaced.

NOTE: See “Filling of Driver Chamber with Liquid” for the correct procedure to
recharge the pump for operation.

Reassembly is the reverse of the tear down. During reassembly, be sure that the
rubber bumper is on the rod on each side (see Figure 5). Install the diaphragm with the
natural bulge to the outside as marked on the diaphragm. Install the heavier plate on the
outer side of the diaphragm. Be sure that the large radius side of each plate is toward the
diaphragm. Place the sealing washer between the inner diaphragm plate and the end
of the rod. Tighten the plate to approximately 25 ft. lbs. (33.89 Newton meters). Torque
while allowing the diaphragm to turn freely with the plate. Hold the opposite side with a
wrench on the plate to prevent rotation of the rod. If the opposite chamber is assembled,
this will not be necessary.

When reassembling the outer chambers and the manifold, the bolts securing the
manifold ange to the chamber should be snugged prior to tightening the manifold ange.
Finish tightening the manifold ange bolts after the chamber bolting is secured.

WARNING

This pump must not be
used for fluid transfer
into aircraft.

WARNING

This pump is
pressurized internally
wit h a ir pre s sur e
during operation.

Always make certain
that all bolting is in good condition and
that all of the correct bolting is reinstalled
during assembly.

WARNING

When used for toxic or

aggressive fluids, the

pump should always

be flushed clean prior

to disassembly.

WARNING

Bef ore d o ing a ny
main-tenance on the
pump, be certain all
pressure is completely

v e n t e d f ro m t he
pump, suct ion, discharge, pipin g, and
all other openings and connections. Be
certain the air supply is locked out or
made non-operational, so that it cannot
be started while work is being done on
the pump. Be certain that approved eye
protection and protective clothing are
worn all times in the vicinity of the pump.
Failure to follow these recommendations
may result in serious injury or death.

WARNING

Airborne particles and
loud noise hazards.
Wear ear and eye
protection.

520-005-000 1/04

Models ST1-A, ST25A Type 4 Page 2

Pumping Diaphragms:

It is recommended that the above procedure be followed to the point of removing
the pumping diaphragm assembly from the pumping unit. Remove eight hex nuts which
allow the outer diaphragm chamber to be lifted from the assembly exposing the PTFE
diaphragm. The PTFE diaphragm can now be lifted from the bolts. The black gasket
(Item 37) is designed to prevent movement and supplement the sealing of the PTFE
diaphragm to retain the driver liquid, and to seal the wetted chamber.

The reassembly should be in reverse as follows.

Install the rubber diaphragm gasket inside the hex head capsrews protruding through
inner chamber. Install PTFE diaphragm in place.

Snug down the outer diaphragm housing (Item 39) evenly torqued on all eight bolts,
alternating from one side to the other in the process. After this subassembly is completed
and reinstalled on the pump as it was removed, the pump should be tested prior to the
reinstallation on the job to make sure the capscrews and nuts are torqued down properly
to prevent leakage around the PTFE diaphragm surfaces. Do not overtighten these bolts.
PTFE has a tendency to cold ow. Torque at 200 inch/pounds (22.59 Newton meters).

A NOTE ABOUT AIR VALVE LUBRICATION

The SandPIPER pump’s pilot valve and main air valve assemblies are designed
to operate WITHOUT lubrication. This is the preferred mode of operation. There may
be instances of personal preference, or poor quality air supplies when lubrication of
the compressed air supply is required. The pump air system will operate with properly
lubricated compressed air supplies. Proper lubrication of the compressed air supply would
entail the use of an air line lubricator (available from Warren Rupp) set to deliver one drop
of 10 wt., non-detergent oil for every 20 SCFM of air the pump consumed at its point of
operation. Consult the pump’s published Performance Curve to determine this.

It is important to remember to inspect the sleeve and spool set routinely. It should
move back and forth freely. This is most important when the air supply is lubricated. If a
lubricator is used, oil accumulation will, over time, collect any debris from the compressed
air. This can prevent the pump from operating properly.

Water in the compressed air supply can create problems such as icing or freezing
of the exhaust air causing the pump to cycle erratically, or stop operating. This can be
addressed by using a point of use air dryer to supplement a plant’s air drying equipment.
This device will remove excess water from the compressed air supply and alleviate the
icing or freezing problem.

ESADS: EXTERNALLY SERVICEABLE AIR
DISTRIBUTION SYSTEM

Please refer to the exploded view drawing and parts list in the Service Manual
supplied with your pump. If you need replacement or additional copies, contact your
local Warren Rupp Distributor, or the Warren Rupp factory Literature Department at the
number shown below. To receive the correct manual, you must specify the MODEL and

TYPE in formation found on the name plate of the pump.

520-005-000 1/04

Models ST1-A, ST25A Type 4 Page 3