Vacuum Pumps N 920 APE-W and N 920 APDC-B
Servicing
Translation of original Operating and Installation Instructions, english, KNF 121690-121708 09/19
35
8. Screw in the new stabilization diaphragm (
17
) and tighten it
hand-tight with the assembly key.
9. Put the diaphragm spacer(s) onto the thread of the new stabili-
zation diaphragm (
17
) (same number).
10. Place the diaphragm recording (
14
) onto the pump housing
(
15
).
The diaphragm recording must be aligned flush with the pump
housing (
15
). This is important for later installation of the dia-
phragm (
9
).
11. Tighten the two screws (
19
) to hand-tightness.
Begin with the outermost screw and make sure that the dia-
phragm recording (
14
) does not move while you are tightening
the screws.
12. Screw the new diaphragm (
9
) into the thread of stabilization di-
aphragm (
17
) and tighten it by hand.
To ensure proper pump performance, it is important to main-
tain a uniform distance everywhere between the outer edge of
the diaphragm (
9
) and the diaphragm recording (
14
). If the dis-
tance is not uniform, you must re-loosen the screws (
19
) and
re-align the diaphragm receiver so the distance is the same
everywhere.
Before you finally tighten the diaphragms, you are recom-
mended to move the diaphragm to the upper dead center by
rotating the fan (
16
).
13. Screw the new diaphragms (
10
) and (
11
) onto the connecting
rods (
12
) and (
13
) and tighten it by hand.
Mount valve plates, intermediate plates and head cover
1. Lay the new O-ring (
18
) on the diaphragm recording (
14
).
2. Lay the new valve plates (Fig. 18/
4
) and the new O-rings (
5
) on
the intermediate plates (
3
), (
7
) and (
8
).
Upper and lower sides of the valve plates are identical. For
correct position see Fig. 18.
3. Lay the new O-ring (
6
) on the intermediate plate (
3
).
4. Place the intermediate plates (
3
), (
7
) and (
8
) on the diaphragm
recording (14) in the position indicated by the drawing lines.
5. Place the head cover (
1
) on the pump housing (
15
); tighten the
screws (
2
) hand tight, evenly and diagonally.
6. Dispose of the old diaphragms, valve plates and O-rings
properly.
Fig. 18: Position of valve plates