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VALVE DISC OPTIONS
Myers Aplex Series acetal resin discs made of DuPont
Delrin
®
are machined flat and smooth to produce
perfect sealing on the lapped-flat face of the seat.
Used successfully in thousands of applications, these
discs are light, slightly flexible under load, and seal
well, even at high pump speeds, providing smooth
pump action.
Acetal resins are very resistant to most corrodents, but
are not usually suitable in fluid temperatures above
120 degrees. Nor do they afford long life at extreme
pressures. Pressure limitations depend on valve size.
But continuous valve operation at pressures above
2,500 psi usually indicates the need of metal
valve discs.
For higher temperatures or pressures, Myers Aplex
Series offers lapped flat, hardened Type 17-4PH
stainless discs, or titanium alloy discs. These metal
discs are less tolerant of any fine grit in the liquid and
are noisier than the acetal resin disc.
PULLING THE VALVE SEAT
First drain the fluid end entirely. For abrasion resistant
valves, use the cage wrench to unscrew the cage from
the seat. For disc valves unscrew the stem from the
seat. Remove the cage, spring and valve from the fluid
end. Attach the Myers Aplex Series puller head to the
puller stem, tighten their tapered threads with a pipe
wrench applied to the knurled areas of the puller stem
and head. Lower the stem and head into the fluid end
and engage the threads of the head onto the
seat threads.
Using a 1/2" bar (or screwdriver), rotate the head
clockwise and thread it fully onto the seat. But do
NOT tighten.
Slide the bridge over the stem. Clean and oil the stem
threads. Oil the face of the wing nut. Thread wing nut
down onto the stem, seating it on the bridge top firmly.
Extract the seat from the pump by striking the wing
nut with a heavy hammer. A hydraulic ram may also be
used. Stand clear of the pump when applying heavy
tonnage, as the entire assembly will jump violently
upward when the pulling energy is suddenly released!
The Myers Aplex Series puller/setting tool and gauge
tool are custom designed and built for each specific
Myers Aplex Series pump model. The same puller head
is used on both suction and discharge seats. The bridge
is made to fit each model, and its proper use will not
damage the valve cover gasket machined counterbore
on the top of the
fluid end.
SALVAGE OF WORN SEATS
Rough valve seat faces may often be renewed by
lapping or grinding, if not deeply fluid-cut.
Perfect flatness is required. A surface grind, followed
by lapping on a lapping plate, provides excellent
smoothness and the flatness needed for good sealing
and smooth running. Metal valve discs may sometimes
be salvaged by grinding or lapping, if not deeply cut
or cracked.
Delrin
®
discs are relatively inexpensive and salvage is
seldom worthwhile. Replace the stem, if severely worn.
Inconel
®
valve springs rarely require replacement.
OTHER PUMP BRANDS
Myers Aplex Series Industries can provide its unique
(patented) valve to fit nearly all brands and models of
multiplex pumps. An Myers Aplex Series seat setting/
puller tool is available, too.
Trouble Possible Cause Remedy
Excessive heat in power end.
(Above 180ºF)
Pump operating backward. Correct rotation.
Insufficient oil in power end. Fill to proper level.
Excessive oil in power end. Drain to proper level.
Incorrect oil viscosity. Fill with correct oil.
Overloading. Reduce load.
Tight main bearings. Correct clearance.
Drive misaligned. Realign.
Belts too tight. Reduce tension.
Discharge valve of a cylinder(s)
stuck open.
Fix valve(s).
Insufficient cooling. Provide adequate cooling for oil or
reduce ambient temperature.
Pump speed too low. Increase speed.
TROUBLE LOCATION AND REMEDY
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