IMO 10/19
IMO-215 EN
5
Obtain the following tools: two (2) M10 wrenches, preferably
one being a ratchet, one (1) hex (Allen) wrench, 3 mm for
QPX1, 5 mm for QPX2, 3 and 4, 6 mm for QPX5, one (1)
screwdriver, one (1) plastic faced mallet.
1. Remove the cover (5) by removing six (four on QPX1)
socket cap screws (21). If the cover cannot be removed,
tap it with a plastic hammer to break the adhesion of
the paint between the body and cover joint.
2. Use air pressure to remove spring preload by partially
stroking the actuator. If the diaphragm (14) is ruptured,
replace as instructed in the previous section.
3. To remove the socket shoulder screw (8) (or socket cap
screw in QPX1) that holds the clevis (7) to the driver arm
(3), first apply some heat to the lower arm to loosen
the Loctite® on threads of the socket shoulder screw.
CAUTION: DO NOT place fingers or hands inside Driver
Housing when disconnecting Clevis from Driver Arm.
4. Slowly increase air pressure until the driver arm (3)
moves slightly off the stop screw (19). Remove the
socket shoulder screw (8).
5. Slowly relieve the air pressure in the actuator. The clevis (7)
should be set against the spring retainer (30), and positioned
symmetrically about the slot in the spring housing.
6. Shut off and bleed the air pressure to zero. Disconnect
the air lines.
7. Remove the hex head screws (27) and hex nuts (29)
holding the diaphragm casing and spring housing
together. CAUTION: DO NOT remove diaphragm casing
hex head cap screws (27) and nuts (29) or diaphragm
casing while the actuator is pressurized.
8. Lift off diaphragm casing (15), remove hex head cap
screw (88), washer (89) and diaphragm (14). Inspect
the diaphragm for signs of wear, rupture or mechanical
damage.
9. Inspect the inside of both the diaphragm casing and
spring housing, as well as the outside of the diaphragm
retainer for any rough spots or foreign matter which
may cause abrasion of the diaphragm.
10. Lift the entire spring cartridge out of the unit.
WARNING:
DISASSEMBLY OF THE SPRING PACKAGE SHOULD NOT BE
ATTEMPTED. SPECIAL EQUIPMENT IS REQUIRED. DISASSEMBLY OF
THE SPRING PACKAGE MAY RESULT IN SERIOUS PERSONAL INJURY. IF
MAINTENANCE IS REQUIRED SHIP THE ENTIRE ACTUATOR TO METSO.
It is usually not necessary to remove the spring housing
(32) from the body (1). However, if removal is required, heat
must be used to loosen the Loctite®. When reassembling,
the information in (Table 3), torque and Loctite®
recommendations must be met. All fasteners should use
Loctite® 271 on the threads. Inspect and clean all components.
Good practice dictates that all bearings should be removed
and replaced. See section 5 of this IMO for the proper
actuator series repair kit number.
3.2
Assembly
To aid assembly, spread light oil or grease on the outside
diameter of the new bearings.
1. Press driver arm bearings (6) into the body (1) and covers
(5). This is best done in an arbor press, but a vise could be
used if care is taken not to damage the bearing. Driver arm
bearings are to be pressed in until they are flush or 0.015
in. (0.38 mm) below the body counterbore or the inside
cover surface. Press clevis bearings (62) into the clevis (7).
2. Apply lubricant, MOLYKOTE® GN grease on the barrel
of shoulder screw (8) prior to assembly. Also, apply
MOLYKOTE ® GN grease to driver arm bearings (6).
3. Place the thrust bearing (31) into the counterbore in the
body of QPX1-QPX5 actuators. Slide the other thrust
bearing onto the trunnion of the driver arm (3). Place the
driver in the body
.
4. Spring housing (32), diaphragm retainer (10) and springs
shall be lubricated with Kendall L-427 Super Blu® or
Mobilgrease™ XHP 222. Lower the spring cartridge into
the spring housing (32). Make sure that the spring package
is not resting on the hex head cap screws (38) which hold
the spring housing and body together. If bearing (64) has
separated from diaphragm retainer (10), hold in place
while lowering spring cartridge into housing.
5. Place the new diaphragm (14) on the diaphragm plate.
Attach diaphragm (14) to diaphragm retainer (10) using
washer (89) and hex head cap screw (88). Torque to the
value specified in (Table 3).
6. Insert the hex head bolt (27) in all holes. Do not force the
bolts through the diaphragm. Install nuts (29) and tighten
uni-formly using the standard practice of tightening
diametrically opposed bolts (criss cross pattern) in
sequence. Follow (Table 3) for tightening torques.
7. Connect a regulated air supply to the pressure port
and slowly increase the air pressure until the holes in
the clevis and driver arm are aligned. Turn clevis a few
degrees, if required, to align holes.
8. Apply Loctite® 271 on the threads of the shoulder screw.
Insert it through the driver arm and clevis. Tighten per
(Table 3).
9. Slowly release air pressure. Assemble cover by using the
socket head screws (21). Apply tightening torque per
(Table 3).
10. Install the indicator pointer (24) if this was previously
disassembled. In female actuators make certain that the
indicator points to the inscribed line in the driver arm. In
male actuators, hold the indicator pointer in place with a
retaining ring (9). NOTE: Refer to Installation instructions
for spring-to-close or spring-to-open configuration.
Table 3
Torque Requirements
Required Tightening Torques In FT•LBS (N•m)
For Various Fasteners
QPX1 QPX2 QPX3 QPX4 QPX5
Nuts for Hex Head
Screws through
Diaphragm Casing (29)
24
(32)
24
(32)
24
(32)
24
(32)
24
(32)
Socket Head
Cover Screws (21)
4
(5)
6
(8)
6
(8)
6
(8)
15
( 20)
Socket Head
Shoulder Screw (8)
35
(48)
55
(75)
132
(179)
132
(179)
132
(179)
Nuts on Actuator
Rod (74)
55
(74)
55
(75)
88
(119)
132
(176)
176
(239)
Hex Head Screws
between Body and
Spring Housing (38)
5
(7)
18
(24)
30
(40)
30
(40)
55
(75)
Hex Head Cap Screws for
Attaching Diaphragm to
Diaphragm
Retainer (88)
19
IN•LBS
(1)
19
IN•LBS
(1)
27
IN•LBS
(2)
10
FT•LBS
(14)
17
FT•LBS
(23)
