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8.4 Diaphragm leakage
If the diaphragm leaks or is broken, dosing liquid
escapes from the drain opening on the dosing head.
See fig.
, pos. 16.
In case of diaphragm leakage, the safety diaphragm
(fig.
, pos. 10) protects the pump housing
against ingress of dosing liquid.
When dosing crystallising liquids the drain opening
can be blocked by crystallisation. If the pump is not
taken out of operation immediately, a pressure can
build up between the diaphragm (fig.
-
, pos. 3)
and the safety diaphragm. The pressure can press
dosing liquid through the safety diaphragm into the
pump housing.
Most dosing liquids don't cause any danger when
entering the pump housing. However a few liquids
can cause a chemical reaction with inner parts of the
pump. In the worst case, this reaction can produce
explosive gases in the pump housing.
To avoid any danger resulting from diaphragm
leakage, observe the following:
•
Perform regular maintenance. See section
•
Never operate the pump with blocked or soiled
drain opening.
– If the drain opening is blocked or soiled,
proceed as described in section
8.4.1 Dismantling the dosing head, diaphragm
and valves in case of diaphragm leakage
•
Take suitable precautions to prevent harm to
health and damage to property from escaping
dosing liquid.
•
Never operate the pump with damaged or loose
dosing head screws.
8.4.1 Dismantling the dosing head, diaphragm
and valves in case of diaphragm leakage
This section refers to fig.
-
.
1. Put on the stipulated personal protective
equipment.
2. Make system pressureless.
3. Take suitable steps to ensure that the returning
liquid is safely collected.
4. Empty dosing head and flush it if necessary.
5. Dismantle inlet, outlet and deaeration lines.
6. Unscrew valves on inlet and outlet side (4, 7).
7. For plastic dosing head:
– Remove screws (6).
– Remove dosing head (5) together with cover
plate (6a).
8. For stainless steel dosing head:
– Remove screws (6) together with washers (6b).
– Remove dosing head (5).
9. Unscrew diaphragm (3) counter-clockwise and
remove it.
10. DDE 60-10:
– Remove flange (2) together with O-rings (2a,
2d).
11. DDE 120-7 / DDE 200-4:
– Remove intermediate ring (2c).
– Remove screws (2b) together with flange (2)
and O-ring (2a).
12. Make sure the drain opening (8) is not blocked or
soiled. Clean if necessary.
13. Check the safety diaphragm (10) for wear and
damage. If the safety diaphragm is damaged,
send the pump to Grundfos for repair. See
section
If nothing indicates that dosing liquid has entered the
pump housing, go on as described in section
8.3.3 Reassembling the dosing head, diaphragm and
valves
. Otherwise proceed as described in section
8.4.2 Dosing liquid in the pump housing
.
8.4.2 Dosing liquid in the pump housing
If dosing liquid has entered the pump housing:
•
Send the pump to Grundfos for repair, following
the instructions given in section
•
If a repair isn't economically reasonable, dispose
of the pump observing the information in section
.
WARNING
Danger of explosion, if dosing liquid
has entered the pump housing!
Death or serious personal injury
Operation with damaged diaphragm can
lead to dosing liquid entering the pump
housing.
- In case of diaphragm leakage,
immediately separate the pump from
the power supply!
- Make sure the pump cannot be put back
into operation by accident!
- Dismantle the dosing head without
connecting the pump to the power
supply and make sure no dosing liquid
has entered the pump housing. Proceed
as described in section
8.4.1 Dismantling the dosing head,
diaphragm and valves in case of
diaphragm leakage
Do not connect the pump to the power
supply!
Immediately separate the pump from the
power supply!
Make sure the pump cannot be put back
into operation by accident!
