SANDPIPER HDF4-M - Manual (Page 9)

hdf3mdl2sm-rev1110 Model HDF3-M & HDF4-M Page 7
that the bumper stays in place allowing the sleeve to press in all the way. Reinstall the
spool, opposite end cap, gasket and bumper on the valve body. After inspecting and
cleaning the gasket surfaces on the valve body and intermediate, reinstall the valve
body on the pump using new gaskets. Tighten the four hex head capscrews evenly
and in an alternating cross pattern.
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-up of the air exhaust can occur under certain temperature and
humidity conditions. Use of an air dryer unit 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 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.
FLAP VALVE SERVICING
Valve inspection requires removal of 3/8" hex nuts and elbows. When the
top suction elbows are removed, the valve and seat are connected as an as-
sembly. When the bottom discharge elbows are removed, the valve and
seat stay with the outer chamber. Visual inspection and cleaning is pos-
sible. If parts are to be replaced, remove the self-locking nuts and all parts
are accessible.
DIAPHRAGM SERVICING
Diaphragms can be inspected or the diaphragm assembly removed without remov-
ing the suction and discharge flanges. Remove (8) nuts around the chamber flange,
and the housing assembly will pull off. Flap valves can be inspected for proper
seating at this point as well as the diaphragm. Use care to keep foreign matter from
behind the diaphragm. The opposite diaphragm may be inspected by the same
procedure. If either diaphragm has to be replaced, follow closely these steps:
Pull the outer diameter of one diaphragm off the (8) capscrews. NOTE: One side
only! On the free diaphragm assembly, use a 3/8" allen wrench to turn the assembly
(diaphragm, plates and screw) loose from the shaft. Once the assembly has turned,
it will turn out by hand by use of the diaphragm. Now the opposite diaphragm as-
sembly and the drive shaft will pull free from the capscrews and pump
intermediate assembly. The interior components consisting of sleeve bearings, rod
seals, and pilot valve actuator bushings are now accessible for service if required.
Hold the shaft in a clamping device making sure to protect surface of shaft so as
not to scratch or mar it in any way. The diaphragm assembly will turn loose. To dis-
assemble the components, turn a 1/4"-20 capscrew by hand into the tapped hole in
the inner plate. This keeps the plate from turning while the socket head capscrew is
removed. To do this, place assembly in a vise so the two protruding ends of screws
are loose in the vise jaws (about 3/4" apart). Turn the center screw loose from the
back plate and the assembly will come apart.