Servicing
Diaphragm pump N87.9 EX
32
Translation of Original Operation and Installation Instruction, english, KNF 323252 04/21
Fig.8 Replacing the structured di-
aphragm
4. Loosen the four screws ( Fig. 8/5).
5. Remove the head plate ( Fig. 8/4) and the intermediate plate ( Fig.
8/1).
The structured diaphragm (8) is visible.
Replacing the structured diaphragm
1. Turn the pump to the side; this keeps the shim rings (10) and the disk
springs (11) from falling into the pump chamber when removing the
structured diaphragm (8).
2. Move the structured diaphragm (8) by turning the counterweight to top
dead center.
3. Lift the structured diaphragm (8) onto opposing side edges; hold the
structured diaphragm and unscrew it counterclockwise.
4. Remove the diaphragm support (9), shim ring(s) (10) and disk spring
(11) from the threaded bolt of the structured diaphragm (8) and keep in
a safe place.
5. Check all parts for contamination and clean them if necessary.
6. Push the diaphragm support (9), shim ring(s) (10) and disk spring (11)
onto the threaded bolt of the new structured diaphragm (8) in this order
(see Fig. 9).
Fig.9 Aligning disk spring
The edge of the disc of the disc spring (11) must be aligned with the
structured diaphragm (8).
7. Move the connecting rod (connection part between drive shaft and
structured diaphragm) to top dead center by turning the counterweight.
8. Screw the structured diaphragm with diaphragm support, shim ring(s)
and disk spring clockwise onto the connecting rod and hand tighten.
Replacing the valve plates/seals
1. Separate the head plate (4) from the intermediate plate (1).
2. Remove the valve plates/seals (2) from the intermediate plate (1).
3. Check the valve seats, intermediate plate (1) and head plate (4) for
contamination and damage. Clean the parts if necessary.
4. Contact KNF in the event of unevenness, scratches or corrosion. Order
and replace damaged parts.
The valve plates/seals are identical for the pressure and suction
side. The same applies for the top and bottom of the valve plates/
seals.
5. Insert the new valve plates/seals (2) in the valve seats of the intermedi-
ate plates (1).
6. Place the head plate (4) on the intermediate plate according to the felt-
tip pen marking.
7. Check the centering of the head plate (4) by means of a slight lateral
movement.
