SANDPIPER MP04D User Manual

SERVICE AND OPERATING MANUAL

Model MP04D

SPILL PREVENTION Design Level 3

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

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
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 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 flow in one direction through the pump.

This MARATHON pump differs from other models in that it utilizes four diaphragms
instead of two. The two rod-connected diaphragms are the driver diaphragms, and the
other two (outermost) diaphragms are the actual pumping diaphragms. Each driver
diaphragm (of Neoprene or other elastomer), and the pumping diaphragm (of TFE), are
separated by a chamber filled with liquid which transmits the reciprocating motion of the
driver diaphragm to the pumping diaphragm. The pumping diaphragms, create the
alternating suction and discharge action to each outer diaphragm chamber. The pumping
diaphragms are the only ones in contact with the liquid being pumped.

Read these instructions completely,

IMPORTANT

before installation and start-up. 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.

WARNING

Take action to prevent static sparking.
Fire or explosion can result, especially
when handling flammable liquids. The
pump, piping, valves, containers or other
miscellaneous equipment must be
grounded.

BEFORE OPERATION

Before pump operation, inspect all
gasketed fasteners for looseness
caused by gasket creep. Retorque loose
fasteners to prevent leakage. Follow
recommended torques stated in this
manual.

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 could happen in the case
of a TFE pumping diaphragm failure.
This diaphragm normally separates the
two liquids. Do not operate this unit if it
has been subjected to freezing
temperatures. Because of the driver liquid
used, possible diaphragm failure may
result.

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
MARATHON 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 10-15 feet (9-14 meters) or less.
For suction lifts exceeding 15 feet of liquid, fill the chambers with liquid prior to priming.

Warren Rupp, Inc., A Unit of IDEX Corporation • P.O. Box 1568 • Mansfield, Ohio 44901 USA • [phone] • Fax [phone]

520-136-000 10/02 Model MP04D Design Level 3 Page 1

Fig. 1 Air Inlet

AIR SUPPLY

Air supply pressures cannot exceed 125 psi (8.61 bar). Connect the pump air inlet
(see Figure 1) 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.

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 flow as desired. If opening the valve increases
cycling rate, but does not increase flow rate, cavitation has occurred, and the valve
should be closed slightly.

For the most efficient use of compressed air and the longest diaphragm life, throttle
the air inlet to the lowest cycling rate that does not reduce flow.

A NOTE ABOUT AIR VALVE LUBRICATION

The MARATHON 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 MARATHON) 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 (available from MARATHON) 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.

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
MARATHON Distributor, or the MARATHON factory Literature Department at the
number shown on page 1. To receive the correct manual, you must specify the MODEL
and TYPE information found on the name plate of the pump.

MODELS WITH 1" SUCTION/DISCHARGE OR LARGER,
AND NON-METAL CENTER SECTIONS

The main air valve sleeve and spool set is located in the valve body mounted on the
pump with four hex head capscrews. The valve body assembly is removed from the pump
by removing these four hex head capscrews.

With the valve body assembly off the pump, access to the sleeve and spool set is made
by removing a retaining ring (each end) securing the end cap on the valve body
assembly. With the end caps removed, slide the spool back and forth in the sleeve. The
spool is closely sized to the sleeve and must move freely to allow for proper pump
operation. An accumulation of oil, dirt or other contaminants from the pump’s air supply,
or from a failed diaphragm, may prevent the spool from moving freely. This can cause
the spool to stick in a position that prevents the pump from operating. If this is the case,
the sleeve and spool set should be removed from the valve body for cleaning and further
inspection.

Remove the spool from the sleeve. Using an arbor press or bench vise (with an
improvised mandrel), press the sleeve from the valve body. Take care not to damage the
sleeve. At this point, inspect the o-rings on the sleeve for nicks, tears or abrasions.
Damage of this sort could happen during assembly or servicing. A sheared or cut o-ring
can allow the pump’s compressed air supply to leak or bypass within the air valve
assembly, causing the pump to leak compressed air from the pump air exhaust or not
cycle properly. This is most noticeable at pump dead head or high discharge pressure
conditions. Replace any of these o-rings as required or set up a routine, preventive

The weight of the air supply line end

WARNING

of the filter must be supported by
some means other than the air valve
cap. Failure to provide support may
result in damage to the pump.

Fig. 2 Exhaust muffler

Fig. 3 Filling the driver chamber

Fig. 4 Purge air in pump by moving

diaphragm rod.

DANGER

Before doing any maintenance on
the pump, be certain all pressure is
completely vented from the pump,
suction, discharge, piping, 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 at all times in the vicinity of
the pump. Failure to follow these
recommendations may result in
serious injury or death.

Model MP04D Design Level 3 Page 2 520-136-000 10/02

maintenance schedule to do so on a regular basis. This practice should include cleaning
the spool and sleeve components with a safety solvent or equivalent, inspecting for signs
of wear or damage, and replacing worn components.

To re-install the sleeve and spool set, lightly lubricate the o-rings on the sleeve with
an o-ring assembly lubricant or lightweight oil (such as 10 wt. air line lubricant).
Re-install one end cap, and retaining ring on the valve body. Using the arbor press or
bench vise that was used in disassembly,

carefully press the sleeve back into the valve
body, without shearing the o-rings. Re-install the spool, opposite end cap and retaining
ring on the valve body. After inspecting and cleaning the gasket surfaces on the valve
body and intermediate, re-install the valve body on the pump using new gaskets.
Tighten the four hex head capscrews evenly and in an alternating cross pattern, at 150
in./lbs. (16.94 Newton meters).

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 flow
and reduce pump performance. When the product source is at a higher level than the
pump (flooded 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 a MARATHON Extractor/Dryer unit should eliminate most
icing problems. Check the exhaust periodically for build-up of ice or contaminants (see
Figure 2).

BETWEEN USES

When used for materials that tend to settle out or transform to solid form, the pump
should be completely flushed 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.

FILLING OF DRIVER CHAMBER WITH LIQUID

The driver chambers are filled at the factory with water.

If you need to substitute another liquid to prevent system contamination, first consult
the factory for chemical compatibility with pump construction.

Follow the steps listed below to replace the liquid in the pump after disassembly or
liquid loss:

1. Filling is accomplished through the pipe plugs at the top of the liquid driver chamber

(see Figure 3).

2. After the driver fluid has been emptied from the pump, the driver diaphragms will

naturally come to center.

3. Remove the entire discharge manifold assembly exposing the ports in the outer

diaphragm chambers.

4. Fill either side with 600 ml. (20.44 fl. oz.) by volume with the driver liquid. It is
imperative that the driver liquid chambers be filled with the correct amount of driver liquid
as too little or too much will cause premature diaphragm failure and erratic pumping.

5. After filling with the proper amount of liquid, if the liquid does not come to the top
of the fill hole, pressure should be applied to the Teflon diaphragm with a blunt tool
through the discharge material flow port in the outer chamber until it does come to the
top (see Figure 4). To facilitate this filling, a taper punch can be used in the hole of the
rod to manually shift the pump.

6. When the driver fluid rises to the top of the fill plug hole, screw the boss plug, with
o-ring installed, into the chamber (see Figure 5). (Do not overtighten.) Remember to keep
pressure on the Teflon diaphragm until the boss plug is tight to prevent air from drawing
back into the chamber.

7. Filling the opposite side is accomplished in the same manner as described in 5 and 6.
The correct amount of fluid will come to the top of the fill hole. Screw in the boss plug.

In the event of diaphragm rupture,

CAUTION

pumped material may enter the air
end of the pump, and be discharged
into the atmosphere. If pumping a
product which is hazardous or toxic,
the air exhaust must be piped to an
appropriate area for safe disposition.

CAUTION

Do not use a wrench on the
diaphragm rod. Flaws on the surface
may damage bearings and seals.

Fig. 5 Tighten the boss plug.

Fig. 6 Ball check valves

Fig. 7 Diaphragm installation

Fig. 8 Torquing the air inlet capscrews

520-136-000 10/02 Model MP04D Design Level 3 Page 3