ProMinent Beta BT4b - 10.2 Replacing the Diaphragm

10.2 Replacing the Diaphragm
WARNING!
A few cubic centimetres of feed chemical may have
accumulated behind the diaphragm in the backplate
following a leak
- depending on the design!
– Take this feed chemical into consideration when you
are planning a repair - especially if it is hazardous!
Personnel:
n
Technical personnel
n If necessary take protective measures.
n Read the safety data sheet on the feed chemical.
n Depressurise the system.
1. Empty
the liquid end (turn the liquid end upside down and allow
the feed chemical to run out; flush out with a suitable
medium; flush the liquid end thoroughly when using hazardous
feed chemicals!)
2. Turn the stroke adjustment knob until it can go no further at 0
% stroke length if the pump is running
(the drive shaft is then
difficult to turn).
3. Switch off the pump.
4. Unscrew the hydraulic connectors on the discharge and
suction side.
5. With
PP types with bleed valve: Firstly remove the bleed valve
(star handle), then lift off the cover of the liquid end with a
screwdriver.
6. Remove the screws (1).
7. Loosen the dosing head
(2) and the backplate (4) from the
pump housing (6) - but only loosen!
8. Hold the pump housing
(6) with one hand and clamp the
diaphragm (3) with the other hand between the dosing head
(2) and the backplate (4).
9. Loosen the diaphragm
(3) from the drive shaft with a gentle
backwards turn of the dosing head (2), diaphragm (3) and
backplate (4) in an anticlockwise direction.
10. Unscrew the diaphragm
(3) completely from the drive shaft.
11. Remove the backplate
(4) from the pump housing (6).
12. Check
the condition of the safety diaphragm (5) and replace if
necessary.
13. Push the safety diaphragm (5) onto the drive shaft only until it
lies flush with the pump housing
(6) and no further!
14. Tentatively screw the new diaphragm
(3) onto the drive shaft
until its stop position.
ð
The diaphragm (3) is now sitting at the end position of the
thread.
15. Should this not work, remove dirt or swarf out of the threads
and
screw the diaphragm (3) onto the drive shaft correctly this
time.
Repair
32