RXF ROTARY SCREW COMPRESSOR UNITS
MAINTENANCE
070.410-IOM (JAN 12)
Page 27
DEMAND PUMP ASSEMBLY
Assembly Notes On Standard Mechanical Seal (Synthetic
Rubber Bellows Type)
NOTE: Read carefully before reassembling pump
The seal used in this pump is simple to install and good
performance will result if care is taken during installation.
The principle of a mechanical seal is contact between the
rotary and stationary members. These parts are lapped to
a high finish and their sealing effectiveness depends on
complete contact.
Prior to installing the rotary portion of the mechanical seal,
prepare and organize the rotor shaft, head and idler assem-
blies, and appropriate gaskets for quick assembly
Once the rotary portion of the mechanical seal is installed on
the rotor shaft, it is necessary to assemble parts as quickly
as possible to ensure that the seal does not stick to the shaft
in the wrong axial position. The seal will stick to the shaft
after several minutes setting time.
Never touch sealing faces with anything except clean hands
or clean cloth. Minute particles can scratch the seal faces
and cause leakage.
1. Coat the idler pin with refrigeration oil and place idler
and bushing on idler pin in the head. If replacing a carbon-
graphite bushing, refer to
"Installation of Carbon Graphite
Bushings"
.
2. Clean rotor hub and casing seal housing bore. Make sure
both are free from dirt and grit. Coat outer diameter of seal
seat and inner diameter of seal housing bore with refrigera-
tion oil.
3. Start seal seat in seal housing bore. If force is necessary,
protect seal face with a clean cardboard disc and gently tap it
in place with a piece of wood. Be sure seal seat is completely
seated in the bore.
4. Place tapered installation sleeve on shaft. Refer to Figure
31. Sleeve is furnished with GG, AS, AK, and AL replacement
mechanical seals. Coat rotor shaft, tapered installation sleeve,
and inner diameter of mechanical seal rotary mem ber with
a generous amount of refrigeration oil. Petrolatum may be
used but grease is not recommended.
5. Place seal spring on the shaft against the rotor hub. Refer
to Figure 32.
6. Slide rotary member, with lapped contact surface facing
away from the spring, over installation sleeve on shaft until
just con tacting the spring. Do not compress the spring. Re-
move the installa tion sleeve.
7. Coat the rotor shaft with refrigeration oil. Install the rotor
and shaft into the casing, slowly pushing until the ends of
the rotor teeth are just below the face of the casing.
Take
care not to damage the seal seat.
8. Leave the rotor in this position. Withdrawal of rotor and
shaft may displace the carbon seal rotating face and result
in damage to the seal.
9. Place O-ring gasket on the head and install head and idler
assembly on pump. Pump head and casing were marked
before disassembly to ensure proper reassembly. If not, be
sure the idler pin, which is offset in pump head, is positioned
up and equal distance between port connections to allow for
proper flow of liquid through the pump.
10. Tighten the head capscrews evenly.
11. If the pump was equipped with a relief valve and was
removed during disassembly, install on the head with new
O-Rings or gaskets. The relief valve adjusting screw cap must
always point towards the suction port.
12. In 2005, the use of single seal bearings were phased out.
Pumps now use “Sealed for Life” bearings that have seals
on both sides. The new bearings can be installed either side
first and do not need to be packed with grease. For older
models with single seal bearings, pack the inner ball bearing
with multi-purpose grease, NLGI #2.
GG, HJ, HL
: Drive the bearing into the bore. Tap the inner
race with a brass bar and lead hammer to position bearing.
Install the inner snap ring.
AS, AK, AL
: Install the bearing retainer washer over the shaft
before installing the ball bearing. Install the ball bearing in
the casing with sealed side towards head end of the pump.
Drive the bearing into the bore. Tap the inner race with a
brass bar and lead hammer to position the bearing.
13.
GG, HJ, HL
: Install the shaft snap ring in groove in the
shaft. See Figure 29.
AS, AK, AL
: Install the bearing spacer over the shaft and
against the single row ball bearing. See Figure 30.
14. Pack the lubrication chamber between the inner ball
bearing and double row ball bearing in the thrust bearing as-
sembly approximately one-half full of multi-purpose grease,
NLGI #2. The thrust bearing assembly will take the remaining
space. See Figures 29 and 30.
Figure 31
Figure 32