15
Preventive Maintenance
The SMU design is virtually maintenance free. Applications with
airborne dust within the vessel should be setup on a periodic
maintenance schedule to ensure optimum performance.
Evaluation should be conducted twice a year. General interior
cleaning and/or cable and wiper seal replacement as described
below should be the primary emphasis.
ATEX and IECEx:
It is
advised that the motor be removed periodically for inspec-
tion and cleaning of the shaft.
Cleaning Requirements
Ensure cover gaskets remain clean so hazardous/environmental
protection is maintained. If necessary, remove excess dust from
inside the SMU with compressed air. Ensure all mechanical
parts can rotate/swing freely. If necessary, replace the wiper seal
as described to ensure free cable travel. Remove any material
build-up which may occur on the plumb bob.
ATEX and IECEx Supplemental Instructions
(Maintenance)
See Bulletin 344K.
Cable and wiper seal replacement
1) Manufacturer observations
- Cable life can last over
100,000 operations. However, in applications with coarse
material or temperature swings, life can be reduced. Cables
that are kinked, frayed or which have peeling of the jacket
require immediate replacement to ensure proper operation.
2) Target operation
- Reliable operation requires a damage-
free cable which can easily navigate through the wiper seal,
around the cable rollers and onto the storage wheel. Cables
should pass through wipers without any resistance.
Cable Replacement Procedure
1. Access plumb bob:
Press the "Down" motor control switch
until enough cable is spooled out so the plumb bob can be
accessed from a port on the vessel. Disconnect power plug.
2. Remove cable:
Cut the cable just above the thimble at the
plumb bob end. Retain hardware. Remove the storage
wheel cover by removing the four screws. Remove cable
from the SMU.
3. Remove wiper seals:
Remove the wiper seal cover. Pull
out wiper seals. Clean wiper seal compartment. Do not
install wiper seals at this time.
4. Attach cable to hub:
Insert cable into slot of reel hub. Loop
the cable over the closest casting boss. Secure cable with
one compression sleeve. Replace storage reel side cover
and route cable around lower corner roller.
5. Spool cable:
Reapply power to the SMU. Motor will briefly
start pulling in cable. Press the "Up" motor control switch and
allow motor to wind cable onto storage reel in even manner.
Release switch when there is just enough cable to perform
the actions outlined in steps 6 and 7 below.
6. Route cable:
Position cable around rollers, measuring
wheel and through the wiper seal compartment and mounting
flange. Do not install wiper seals yet.
7. Reattach plumb bob:
Pass cable through two compression
sleeves, around thimble and back through compression
sleeves. Crimp compression sleeves.
8. Install wiper seals:
Install wiper seals as explained in the
Wiper Seal Replacement section.
9. Re-establish operation:
Remove all slack from cable and
be sure it passes freely through both wipers. Press System
Reset Switch and allow SMU to fully wind cable onto
storage reel.
Wiper Seal Replacement
(See Figure 13)
1. Create cable stack:
Press the “Down” motor control switch
so plumb bob is not socketed and until there is enough cable
slack to allow setting the plumb bob aside.
2. Wiper removal from the cartridge:
Grasp the cable from
between the two wipers and pull toward you in direction of
arrow “A” while also pulling on the wipers. There is a slot on
the Viton
®
wiper that must be aligned parallel with the cable
(facing toward the back of the cartridge). It is necessary for
the cable to be aligned and somewhat embedded in the slot
in order to remove the wiper without pinching the cable. The
brush wiper can be pulled out regardless of alignment.
3. Wiper removal from cable:
Viton wiper: Firmly pull cable through the slot in direction of
arrow “B”.
Brush wiper: Spread open the wiper enough to pull cable
through.
4. Install replacement wipers or cleaned originals:
Brush wiper: Spread open the wiper enough to pull cable
through and slide it onto the cable until centered and reclose.
Viton wiper: Firmly pull cable through the slot until the cable
pops into the center hole. Do not flex or bend this wiper or the
bond between the metal and rubber components may be
compromised.
5. Install wipers in cartridge slots:
Viton wiper: Align the wiper so that the slot faces the back of
the cartridge (direction of arrow “B”). Align the cable parallel
over the slot so that it almost lies in the slot. This is necessary
to prevent the cable from getting pinched or jammed between
the wiper and the cartridge slot. Slide the wiper into the
cartridge slot. The cable must move freely through the hole
once installed.
Brush wiper: Slide the wiper into the cartridge slot while
slowly rotating the wiper around the cable. Rotating the wiper
helps keep the bristles from getting hung up on the front edge
of the cartridge slot. Installed correctly, the wiper should be
fairly easy to revolve around the cable.
6. Re-establish operation:
Remove all slack from cable and be
sure it passes freely through both wipers. Press System Reset
Switch and allow SMU to fully wind cable onto storage reel.
B
WIPER SEAL MAINTENANCE
A
CARTRIDGE
Figure 13
VITON WIPER
BRUSH WIPER
