SANDPIPER RS20 Metallic - Manual (Page 17)

rs30mdl1sm_haz duty-rev0614 Model RS30 Hazardous Duty Metallic Page 15
DIAPHRAGM AND CHECK VALVE SERVICING
• To service the diaphragms, first shut off and bleed the air being supplied to the pump. For safety
purposes the air supply line should be disconnected from the pump.
• Then shut off the suction and discharge lines to the pump.
• Bleed the pressure from the pump suction and discharge lines and remove the lines from the pump.
• Drain any remaining liquid from the pump.
• During the servicing of the diaphragms, consult the “Composite Repair Parts Drawing” (p.7).
Step #1: Removing the Manifolds
• Using a 9/16" wrench or socket, remove the 16 cap-screws, hex-nuts, and lockwashers that fasten the
manifolds to the outer chambers.
• Remove the manifolds.
Step #2: Inspect Check Valve Components
• Inspect the four check balls for wear, abrasion or cuts on the spherical surface. Also inspect the
four check valve seats for cuts, abrasive wear or embedded material around the area where the ball
contacts the seat.
• For maximum pump performance and efficiency, the surface of the ball must seal against the seat
without any gaps.
• Replace worn or damaged parts as necessary. Consult the “Composite Repair Parts Drawing” for part
numbers and quantities.
Step #3: Removing the Outer Chambers
• Using an 11/16" and a 5/8" wrench or socket, remove the 16 cap-screws, and hexnuts that fasten the
outer chambers, diaphragms, and inner chambers.
Step #4: Removing the Diaphragm Assemblies
• Once the outer chambers are removed, use a 1-1/16” (27mm) wrench or six-pointed socket to remove
the diaphragm assemblies (outer plate, diaphragm, and inner plate) from the diaphragm rod by turning
counterclockwise.
• “AirVantage CAUTION” – When diaphragm assemblies are removed, watch for the brass probe
tips located on the end of the sensor rod. There is one brass probe tip and one o-ring per side.
Inspect the probe tips and o-rings for wear. For every diaphragm service, these parts should be
replaced and are available in kit form. Consult the “Composite Repair Parts Drawing” for part
numbers and quantities.
• The diaphragm connecting rod will usually stay with one of the diaphragm assemblies. Install the rod in
a vise fitted with soft jaws and loosen the diaphragm assembly from the rod. Take care not to scar the
surface of the rod.
• Insert a 1/4-20 capscrew or set screw into the smaller tapped hole in the inner diaphragm plate.
• Insert the protruding stud and the 1/4-20 fastener loosely into a vise. Use the 1-1/16" wrench or socket
to remove the outer diaphragm plate by turning counter-clockwise.
Step #5: Inspect Diaphragms, Diaphragm Connecting Rod, U-cup Seals and
Bumpers
• Inspect the diaphragms for cuts and/or punctures in the flexing area. Even the smallest hole or crack
can allow product to get to the air side of the pump. If there is product noticed on the air side of the
diaphragm, there is a good possibility the diaphragm needs to be replaced.
• “AirVantage CAUTION” – If product is observed on the air side of the diaphragm, refer to the
“AirVantage Servicing” section of the service manual.
• Abrasive wear of the diaphragm needs to be inspected at the point where the diaphragm contacts the
outer chamber or where the diaphragm plates contacts the diaphragm. Chemical attack of a diaphragm
will usually result in swelling or deformity. Replace the diaphragms if necessary. Inspect the diaphragm
connecting rod for scars, nicks or any imperfection that could cause damage to the u-cup seal. Inspect
the u-cup seal for imperfections on the sealing lip. Inspect the bumpers for damage on the face.
Replace components as necessary. Consult the “Composite Repair Parts Drawing” for part numbers
and quantities.
Step #6: Assemble the Diaphragms
• Push the threaded stud of the outer diaphragm plate through the center hole of the diaphragm. Thread
the inner plate clockwise onto the stud.
• Insert the loose assembly with the above 1/4-20 fastener back into the vise. Use a torque wrench and
1-1/16” socket (27 mm) to tighten the diaphragm assembly together to 480 in.-lbs. (54.23 Newton
meters).
• Allow a torqued assembly to set for 15-minutes. This will allow the diaphragm to relax. Re-torque the
assembly to compensate for stress relaxation in the clamped assembly.
Step #7: Installing the Diaphragm Assemblies to the Pump
• Make sure the bumper is installed over the diaphragm rod. Thread the stud of the one diaphragm
assembly clockwise into the tapped hole at the end of the diaphragm rod until the inner diaphragm plate
is flush to the end of the rod.
• “AirVantage CAUTION” – With the pump lying on one inner chamber, pull the sensor rod UP
the full length of its stroke. Insert the brass probe tip and o-ring into the sensor rod. Insert rod
and diaphragm assembly into pump, taking care not to damage the u-cup seal. Make sure the
diaphragm plate contacts the brass probe tip and stays in contact with it. This will help make
sure the probe tip does not fall out during reassembly.
• Align the bolt holes in the diaphragm with the bolt pattern in the inner chamber. Fasten the outer
chamber to the pump, using the cap screws, and hex nuts, but do not tighten. Flip the pump over so
that it is now setting on the outer chamber. Pull the diaphragm rod out as far as possible. Make sure the
bumper is installed over the diaphragm rod.
• “AirVantage CAUTION” – Install the second brass probe tip and o-ring on the sensor rod.
• Thread the stud of the remaining diaphragm assembly clockwise into the tapped hole at the
end of the diaphragm rod (item 34) until the diaphragm plate contacts the end surface of the
diaphragm rod. If the bolt holes in the diaphragm do not line up with the inner chamber, use a
1-1/16” (27 mm) socket or wrench to tighten the assembly until they line up.
• Fasten the remaining outer chamber to the pump, using the cap screws and hex nuts, and once again,
do not tighten at this point. Tip the pump 90° and set it on a flat surface with the discharge side of the
chambers down. This will allow the outer chambers to be aligned with each other. Tighten the sixteen
fasteners. Make sure to use a cross tightening pattern to ensure an even sealing on the diaphragm.
Step #8: Re-install the Check Valve Components and Manifolds
• While the pump is setting on the discharge side, insert the check balls and seats on the suction side of
the pump. Make sure the seats fit within the counter bore of the chambers. The suction manifold can
now be installed, using the eight cap screws,
hex nuts and lock washers.
• Flip the pump 180° and install the seats and
check balls on the discharge side.
• Now the discharge manifold can be installed
and fastened using the remaining cap screws,
hex nuts, and lock washers.
OVERLAY DIAPHRAGM SERVICING
The overlay diaphragm is a PTFE diaphragm
that fits over the exterior of the diaphragm. The
PTFE diaphragm is used to protect the standard
diaphragm from the chemicals being pumped.
Repeat step #6 when diaphragms need to be
serviced.
Read these instructions
completely, before
installation and start-up.
It is the responsibility of
the purchaser to retain
this manual for reference. Failure to
comply with the recommendations stated
in this manual will damage the pump, and
void factory warranty.
IMPORTANT