SIGMA 150Ci - Manual (Page 36)

MAINTENANCE INSTRUCTIONS
4.6
Model 880 Delta, Model 880 Sigma and Model 880 Elite
annual maintenance requirements
Model 880 Delta, Sigma and Elite exposure devices must receive inspection and maintenance
at least once a year.
The locking mechanism and outlet port mechanism must be removed from the exposure
device and disassembled for proper cleaning, inspection and lubrication on components that
are critical to safety.
These procedures can only be performed on an empty exposure device, which requires
transfer of the radioactive source assembly into an approved storage container.
The inspection and maintenance procedures must be performed by personnel specifically
trained and qualified for this work. AEA Technology QSA service engineers will service these
systems at one of their service centers or in the field upon request.
Trained and qualified personnel who wish to perform this work should use the
following procedure:
1 Perform a daily inspection of the system and transfer the radioactive source assembly
into an approved storage container. Disengage remote controls and source guide tubes.
The exposure device must be empty for the following steps. (See page 4.3)
2 Remove the four
5 /
16
-18 x 1 1 /
2
in socket button-head screws that retain the locking
mechanism plate from the empty Model 880 device using the tamperproof tool bit mounted
in a ratchet.
3 Remove the 10-32 socket head screws that retain the selector-ring and plunger lock
housing from the mounting plate using a 5 /
32
in Allen wrench.
4 Disassemble the locking mechanism assembly, taking care not to lose the spring loaded
parts. Place the disassembled locking mechanism components into a pan filled with fresh,
clean solvent. Clean all parts using a brush to dislodge any dirt or grease. Remove cleaned
parts from the solvent bath, dry and place on a clean surface. Inspect all parts for wear.
Replace worn parts as necessary.
Discard all used locking mechanism springs and replace with new springs.
When ordering spare parts, quote the model and serial number of the exposure device as
well as the part number to ensure correct replacement.
Remove the lock retainer from the mounting plate by unscrewing the two 10-32 x
1 /
2
in
socket head screws using a 5 /
32
in Allen wrench. Remove the plunger lock from the lock
retainer by removing the cap screw using a 3 /
32
in Allen wrench. Clean the lock plunger,
lock retainer and springs in a solvent bath. Ensure the lock plunger is thoroughly rinsed to
remove all dust from the key tumblers. Removed the cleaned parts from the solvent bath
and dry thoroughly, using compressed air to dry the lock tumbler. Inspect all parts for wear.
Replace worn parts as necessary. Lubricate the plunger lock barrel and tumbler using two
drops of a light viscosity oil. Apply Vibratite™ thread sealant to the lock set screw and install.
Check the plunger lock for proper function by using the key to engage and unlock. Apply
Vibratite™ to the lock retainer's 10-32 x 1 /
2
in screws, then mount the lock retainer to the
locking mechanism plate. Hand-tighten the screws using a 5 /
32
in Allen wrench.
Apply a light coating of lubrication to the inside surfaces of the selector ring and selector
body using MIL-G-23827B or C, MIL-PRF-23827C grease or equivalent radiation resistant
grease. Do not lubricate the lock slide and sleeve. Note that some types of greases may
undergo chemical changes and form tars when exposed to radiation.