SANDPIPER GH2 - Manual (Page 2)

Model GH2 Page 2 gh2dl1sm-REV0714
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.
DIAPHRAGM SERVICING/FILLING DRIVER FLUID
Motive power is delivered to the single diaphragm of the pump through a
fluid cell located between the diaphragm and the drive piston. During preventative
maintenance servicing (where the diaphragm has not ruptured, and the fluid cell is still
filled), the fluid should be drained from the chamber by removing the pipe plug, in the
lower most portion of inner chamber, item 54.
To fill the fluid cell, the piston(s) must be on full discharge stroke. To do this and hold
during fill procedure, remove item 46, (fitting) from the cylinder cap (item 15) and insert
gas pressure. This need not be more than 10 PSI. This will move the piston(s) and hold
them in the discharge position. Remove the pipe plug at the top of the fluid chamber,
and fill the chamber with ethylene glycol (anti-freeze). The chamber will take 3000 ml
(101.5 fluid ounces) of fluid. If the diaphragm is PTFE, use 2800 ml (95 fluid ounces).
Tilt the pump to evacuate air pockets from the fluid chamber. A box wrench can be used
to flex the diaphragm and purge air from the fluid chamber. Fill the chamber to the top
of the fill hole, and re-insert the pipe plug, using thread compound.
If the glycol cell fluid is not compatible with the pumped product or would form a
potentially dangerous mixture if the diaphragm ruptured, consult the factory before
choosing an alternative fluid.
CYLINDER PISTON SERVICING
The driver fluid must be drained (see above) to service the cylinder piston.
The piston seals are different on the natural gas side versus the driver fluid side.
Typically, the fluid side will require replacement before the gas side. Remove the nuts
and washers that secure the gas side piston cap and inner fluid chamber to the inter-
mediate bracket. The cylinders may now be removed. Inspect the cylinder wall carefully.
Scratches can cause driver fluid to leak to the gas side of the pump, which can find
its way to the exhaust muffler. Scratches on the gas cylinder will cause too much gas
to leak when on pressure stroke. The locknuts holding the cylinder to the rod can now
be removed. Carefully inspect the piston for scratches, burrs and wear, especially if
the piston seals are worn.
The piston seals can now be inspected or replaced. NATURAL GAS SIDE–The
gas side piston has a T-Seal. If the seal is worn showing flat areas or gouges, it
will require replacement. Remove seal and back-up (spacer). Remove wear rings
and carefully inspect for wear. During reassembly make sure the ends of the back
up spacer and wear ring end are not across from each other. WET SIDE–The wet
side piston has a yellow PSP seal. Inspect for flat spots and gouges. Behind the
seal is an energizer ring that helps to load the seal against the cylinder wall. (The
energizer ring is included with the new seal.) The wear rings are the same as on the
air side. Again, make sure the ends are not across from each other.
Reassembly of both pistons is the opposite of removal. Make sure the side of the
locknut with the seal is next to the piston. The groove in the piston or o-ring (item
35), must be toward the pump center (o-ring seals next to the rod). Apply a heavy oil to
the piston seals when sliding on the cylinder. The piston/nut should be torqued at 500
in./lbs. (56.49 Newton meters). The studs that secure the cylinders to the intermediate
should be torqued at 250 in./lbs. (28.24 Newton meters).
IMPORTANT NOTE: Reas-
sembly of the wet side piston/seal assembly differs from the gas side in that it must be
carefully pressed into the cylinder. An arbor press is commonly used for this purpose.
NATURAL GAS VALVE LUBRICATION
The SandPIPER pump’s pilot valve and main gas 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 gas supplies when
lubrication of the compressed natural gas supply is required. The pump gas system
will operate with properly lubricated compressed gas supplies. Proper lubricatrion
of the compressed gas supply would entail the use of a natural gas line lubricator
set to deliver one drop of 10 wt., non-detergent oil for every 20 SCFM of gas
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
Do not smoke near
t h e p u m p o r u s e
the pump near an
open flame. Fire or
explosion could result.
WARNING
This pump must not
be used for fluid
transfer into aircraft.
WARNING
T h i s p u m p i s
pressurized internally
w i t h n a t u r a l g a s
p r e s s u r e d u r i n g
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
Before doing any
main-tenance on the
pump, be cer tain
a l l p r e s s u r e i s
completely vented
from the pump, suction, discharge, piping,
and all other openings and connections.
Be certain the natural gas 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.
WARNING
Pump complies with EN809 Pumping
Directive, Directive 98/37/EC Safety of
Machinery.