Blagdon Pump X25 Metallic - Manual (Page 8)

x25fvmdl1sm-rev0411 Page 6
AIR SUPPLY
Air supply pressures cannot exceed 125 psi (8.61 bar). Connect the pump air inlet
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 1/2"
(12.7 mm) 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.
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 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 Capscrews and elbows. When the top suction
elbows are removed, the valve and seat are connected as an assembly. When the bottom
discharge elbows are removed, the valve and seat stay with the outer chamber. Visual
inspection and cleaning is possible. If parts are to be replaced, remove the self-locking
nuts and all parts are accessible.
Caution should be used while reassembling Flap valves. The valves are designed for
some preload over the retainer hinge pad. This is done to insure proper face contact
with the seat. After all parts are in place, tighten the lock nuts down on the assembly to
the point where visual inspection shows that seat and valve face mate without gap. This
is important for dry prime. However, after priming action has started, valves will function
due to differential pressure without concern or trouble.
DIAPHRAGM SERVICING
Remove the eight bolts securing the elbows to the chamber. Remove the four nuts
and four capscrews securing the outer diaphragm chamber flange and remove the
chamber. Loosen the capscrew securing the diaphragm and plate to the rod by leaving
the diaphragm engaged with the capscrews around the outer flange, preventing rotation
of the rod. DO NOT USE A WRENCH ON THE DIAPHRAGM ROD. FLAWS ON THE
SURFACE MAY DAMAGE BEARINGS AND SEAL.
During reassembly make certain that the rubber bumper is on the rod on each side.
Install the diaphragm with the natural bulge outward as indicated on the diaphragm.
Install the outer plate on the outside of the diaphragm. Place the sealing washer between
the inner diaphragm plate and the end of the rod. Tighten the capscrew to approximately
25 ft. lbs. (33.9 Newton meters). Torque while allowing diaphragm to turn freely with
plates. Except for EPDM Rubber, use a lightweight oil between plates and diaphragm
when doing this procedure. For EPDM water can be used. Use a wrench on the Hex of
the opposite side to keep the rod from rotating. If the opposite chamber is assembled,
the rod need not be held. The Flap Valves can also be inspected for proper seating at
this point.