Setting The Valve Seat; Installing O-Rings, Abrasion Resistant Spring And Cage; Installing Disc, Spring, Disc Valves And Stem; Valve Spring Options - Pentair MYERS APLEX Series Installation And Service Manual

experience. By locating these on the rim, setting/
pulling forces are now applied only to the rim of the
seat, never to the webs (or "spokes"), or to the center
section. Distortion of the seat is eliminated.
Access to these seat threads is provided by the removal
of the valve cage on abrasion resistant valve or the
spring retainer on disc valves which is screwed onto the
seat. An anti-seizing lubricant applied to all threads is
good insurance against future difficulty.

SETTING THE VALVE SEAT

PULLER STEM
PUMP FLUID END
PULLER HEAD
Effective pressure-sealing between tapered (male) seat
and tapered (female) fluid end deck is possible ONLY
if the tapers are absolutely clean and dry just prior to
installation. Thoroughly clean surfaces using a clean
solvent. Dry with a CLEAN shop towel.
Examine the cleaned fluid end deck tapers, using a
flashlight, and remove all deposits of gyp, salt, or other
incrustation. Using emery cloth, lightly rub out any
minor imperfections found in the deck taper.
The puller stem and puller head are provided with
tapered (locking) threads. Screw them together using
two pipe wrenches applied to the knurled areas
provided. Then screw the valve seat onto the puller
head by hand until it shoulders against the puller
shoulder. Do not tighten.
Lower the seat and puller assembly into the fluid end,
squarely setting the seat into the deck. Then pound the
top of the stem with a 6 pound hammer.
Unscrew the head and stem from the seat using a 1/2"
bar (or screwdriver) into the hole provided at the top
end of the stem.
INSERT 1/2" BAR TO
UNSCREW HEAD
FROM SEAT
DISCHARGE
VALVE DECK
SUCTION VALVE
SEAT
INSTALLING O-RINGS, ABRASION
RESISTANT SPRING AND CAGE
Install nitrile O-ring over the threaded
section of the seat and position it at
the bottom of the threads. Install the
polyurethane insert into the valve. The
insert may be heated in hot water to
make it flexible enough to stretch over
the valve. Position the valve into the
seat. Install the valve spring. Apply
anti-seizing lubricant to the threads of
the valve cage and screw the cage on
to the threaded valve seat with cage
setting tool.
INSTALLING DISC, SPRING,
DISC VALVES AND STEM
Myers Aplex Series offers discs of Delrin
of 17-4PH S.S. hardened and ground, and of titanium
alloy.
Position the disc and Inconel
aligning the hole in the disc with the stem threads in
the seat center.
The stem, spring retainer, and locknut are shipped from
Myers Aplex Series already assembled and tightened
with a torque wrench with Loctite
top stem threads only.
Stem Threads
1/2"-13UNC
Use an anti-seizing lubricant in these threads. This
is very necessary when seats and stems of Type 316
stainless steel are selected (optional) to prevent
galling. CLEANLINESS of threads and other contacting
surfaces is of paramount importance in the assembly of
all valve elements.

VALVE SPRING OPTIONS

All Myers Aplex Series valve springs are made of
Inconel material, precisely designed and fabricated.
®
Unless otherwise specified, the standard spring is
furnished. It provides excellent results in the great
majority of applications.
Pumps employed in marginally available NPSH
conditions may require a softer spring, to reduce the
required NPSH. For these special conditions, Myers
Aplex Series can supply light valve springs which exert
lower pressure on the valve disc. The use of light valve
springs may be limited by the choice of plunger size
and/or limited by the chosen speed of the pump. Light
valve springs may be impractical for pump models
fitted with their maximum plunger size, or which
22
acetal resin,
®
spring on the seat,
®
sealant added to the
®
Tightening Torque
65-75 ft. lb.