2202L5JE-DA-C5-N_2015.05.
5 Maintenance and Inspection
Compound 2-stage Screw Compressor
5.4 Disassembly and Inspection
1612LSC Speed Increaser Type
5-20
Figure 5-4 Unloader Cover Block
Indicator Cam Mounting Parts
5.4.3 Unloader
Cover
The unloader cover [74] contains the indicator cam [77], which
converts the linear motion of the unloader slide valve to a
rotational motion, and its attachment parts.
5.4.3.1 Disassembly
a) Remove the hexagon socket head cap screws [76] for
attaching the unloader cylinder cover.
b) The unloader cylinder cover can be pulled straight out as
is because the indicator cam [77] attached to the unloader
cylinder cover is stuck to the inner side of the unloader
push rod [67] in the unloader cylinder, and the grooved pin
(guide pin) [68] is in the groove of the indicator cam.
Ensure that the unloader cylinder cover is not bent
because the axis part of the indicator cam will also become bent.
c) If the indicator cam does not move properly, check the spiral groove of the indicator cam, bearing
and guide pin. Disassembly sequence is as shown below.
c-1) The bearing gland [80] that holds the indicator
cam is secured to the cylinder side of the
unloader cover. Remove the three hexagon
socket head cap screws [81] that are securing
the bearing gland.
c-2) Now, the indicator cam can be pulled out as it is,
together (attached to its shaft) with its ball
bearing [78] and external snap ring [79] securing
the bearing.
c-3) The spring retainer [84], spring [83] and V-ring
[82] are attached, in this order, to the inside of
the unloader cover.
The outer diameter of the Teflon V-rings is
attached tightly to the holes of the unloader cover. These V-rings, once removed, cannot be
reused because their tongue portion gets damaged. So be careful.
5.4.3.2 Inspection
a) Check the packing portion of the indicator cam shaft
for any flaw. If the refrigerant leaks without any flaw
observed in this part, it should be due to a defect of
the V-ring or installing the V-ring without sufficient oil.
In this case, replace the V-ring.
b) Check the spiral groove of the indicator cam. If defect
such as damage or wear is found, replace it with a
new one.
V-ring
