Index revision : I - November 2018
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6.2.2. Disassembly of the isocyanate pneumovalves
Removal of the needle:
•
Step 1
: Tighten the needle with a vice in order to ovalize it, turn of 90° and to start again
to tighten.
•
Step 2
: Make lever with a grip to extract it from the axis.
WARNING : Remain straight in order not to fold the part "fir tree".
•
Step 3
: On a small chuck of drilling machine vertically positioned (not to twist the axis) to
block the part "fir tree" to prevent that the axis turns at the time of the unscrewing of the
nuts of the piston.
•
Step 4
: Unscrew the cap nut (ref.: X4KEHB003), remove the red plate (Ref.:1410082), the
external circlip (ref.: X4KQNT117), the lock washer (ref.: 900000571), the spring
(Ref.:449089), and the nut M3 (Ref.:X4KEHU003).
•
Step 5
: Remove the pneumovalve from the chuck, remove the flat washer
(Ref.:X4KDZU003) and the sealing ring (ref.: J4BRND032) (fold it with a grip and unscrew).
•
Step 6
: Disunite the axis of the piston, the piston is stuck on the axis by the joint-sealing
product, to separate them, install the pneumovalve on the block support (ref.: 1315253)
and give a blow of mallet on the axis.
•
Step 7
: Extract the piston unit, the sealing ring (ref.: J4BRND032) (fold it with a grip and
unscrew), the washer (Ref.:1412147), if necessary install the axis on the chuck to unscrew
the nut M3 (ref.: X4KEHU003).
•
Step 8
: Remove the axis, extract the two screws milled (Ref.:X4EVSF123) to remove the
stuffing box from the body, leave the spring bushing (ref.: 449093) and the drain washer
(ref.:749985), the spring (ref.: 449095), the equipped seal cartridge (ref.: 749987), the ring
Teflon (ref.: 749986) and biconical sealing ring (ref.: 441117).
•
Step 9
: If necessary to replace the seal of piston (ref.: 449091), for that, to block the body
of piston on a vice equipped with jaws with vertical V-shaped grooves or a standard grip
"multi-grip" (to protect the nozzles not to stripe the part), unscrew the nut, remove the
damage seal, clean the body of piston and the nut, to plate it well on the body of piston,
put a drop of loctite "oléoétanche 542" on the bottom of the threading of the piston (with
screwing, the nut will distribute the product on the seal), screw the nut side chamfer resting
against the seal and tighten moderately from 1/4 to 1/2 turn (too much to tighten, the
seal becomes deformed). Wipe the excess of product.
•
Step
10
: Clean all the reusable parts, pass the die M3 on the threading of the axis if this one
is reusable (it should neither be striped, nor twisted).