Diaphragm Vacuum Pumps N 920__.18 and N 920 KT.29.18G
Servicing
Translation of original Operating Instructions, English, KNF 121416-121419 07/18
23
Change diaphragms
1. Turn the diaphragms (
16
) (2 pieces) and (
22
) (1 piece) out-
wards with your hands, counterclockwise. For this, turn the fan
(
20
) such that you can easily grip each diaphragm with your
hands.
Make sure the diaphragm spacers being between diaphragm
and connecting rod (
21
) do not fall into the pump housing.
If diaphragm spacers should adhere to the diaphragms, take
them off and put them on the thread of the corresponding
connecting rod.
The same number of diaphragm spacers must be mounted
as were used for the previous assembly. This is necessary, in
order to ensure the pump's pneumatic performance.
2. Screw the new diaphragms (
16
) (2 pieces) and (
22
) (1 piece)
onto the connecting rods (
21
) and tighten it by hand.
Before you finally tighten the diaphragm, you are recom-
mended to move the diaphragm to the upper dead center by
rotating the fan (
20
).
3. Put head plate (
10
) with intermediate plates (
11
), (
14
) and (
15
)
on adapter (
17
).
Change valve plates
1. Mark the position of head plate (
10
) and intermediate plate
(
11
) relative to each other by a drawing line with a felt-tip pen.
This helps avoid incorrect assembly later.
2. Mark the position of head plate (
10
) and intermediate plate
(
14
) relative to each other by two drawing lines with a pencil.
3. Mark the position of head plate (
10
) and intermediate plate
(
15
) relative to each other by three drawing lines with a pencil.
4. Undo the three screws (
7
) in head plate (
10
) and remove head
plate from intermediate plates (
11
), (
14
) and (
15
).
5. Remove valve plates (
13
) and O-rings (
12
) from intermediate
plates (
11
), (
14
) and (
15
).
Instead of lying on intermediate plate, O-rings could stick to
head plate (
10
).
6. Lay the new valve plates (
13
) and the new O-rings (
12
) on the
intermediate plates (
11
), (
14
) and (
15
).
Upper and lower sides of the valve plates are identical. For
correct position see fig. 9.
7. Dispose of the old diaphragms, valve plates and O-rings
properly.
Fig. 9: Position of valve plates
Содержание N920 AP.18
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