Diaphragm - Grundfos DMH 25X Installation And Operating Instructions Manual

10.6.6 Checking the oil level
1. Switch off the pump, check the oil level and add oil, if necessary.
2. Refit the oil-filling screw (F).
After initial start-up and after each time the diaphragm is
changed, tighten the dosing head screws.
After approximately 6-10 operating hours or two days,
Caution
cross-tighten the dosing head screws using a torque
wrench.
Torques
Pump model
DMH 251, 10 bar
DMH 251, 16 bar
DMH 251, 25 bar
DMH 252
DMH 253
DMH 254
DMH 255
DMH 257
10.7 Replacing the diaphragm for dosing head with
double diaphragm
Warning
Wear protective clothing (gloves and goggles) when work-
ing on the dosing head, connections or lines!
The dosing diaphragm should be replaced with each gear
oil change.
Before removing the dosing head, valves and lines, empty
any remaining medium in the dosing head into a drip tray
by carefully unscrewing the suction valve.
Only use original Grundfos gear oil!
For product numbers, see "Service kit catalogue" on
Note
www.grundfos.com
10.7.1 Removing the dosing head
1. Close the suction and discharge lines and loosen the suction
and discharge valve connections.
2. Loosen the six dosing head screws (1q with 2q).
3. Remove the dosing head (2).
10.7.2 Replacing a double diaphragm
1. Clean the intermediate disk (3q), sealing rings (4q) and covering
rings (5q). After a diaphragm breakage, replace the parts by
new ones.
2. Remove both clamping sleeves (6q) slightly using pliers. After a
diaphragm breakage, replace the parts by new ones.
3. Measure the outer wall thickness of both new diaphragms (Q1
and Q2): s1 < s2 .
(Q1) (Q2)
38
2q
Torque
1q
[Nm]
8-10
10-12
2
13-15
8-10
10-12
50-54
Installation of diaphragm
50-54
1) The shape of the diaphragm varies depending on pump type.
50-54
Caution
4. Fit both new diaphragms (Q1 and Q2) and the parts (3q - 5q) in
the correct order, as is shown in the diagrams (the clamping
sleeves (6q) are used for centring purposes).
Diaphragm on dosing-head side
s < s
1
Q1 3q - 5q Q2
1)
Pos. Components
1q Dosing head screw
2q Intermediate disk
2 Dosing head
Q1/Q2
See fig. Diaphragm on dosing-head side
3q - 5q
Observe correct installation of diaphragms (Q1 and
Q2)! See fig. Diaphragm on dosing-head side.
Fit the thinner diaphragm (Q1) on the dosing side and
the thicker diaphragm (Q2) on the oil side/pump side!
S
6q
3q
2 Q1 5q 4q 3q 4q
Pos. Components
S Contact pressure gauge (installation position)
Q1 Diaphragm on dosing-head side
Q2 Diaphragm on oil side/pump side
3q Intermediate disk
4q Sealing rings
5q Covering rings
6q Clamping sleeves
2
5q Q2