KNF Laboport N86 KN.18 Mode D'emploi page 49

Mini Laboratory pumps N 86.18, N 811.18
Fig. 8 Pump head
Translation of original Operating Instructions, English, KNF 121435-121438 04/18
Change diaphragm
1. Using a small screwdriver, between the housing (1) and the
outer edge of the diaphragm (8), carefully lever the edge of the
diaphragm lightly upwards
2. Grip the diaphragm (8) on opposite sides, unscrew it about two
turns (anti-clockwise).
3. Hold the pump with one hand, so that the head is pointing
downwards. Turn the diaphragm (8) anti-clockwise to unscrew
it.
4. Take the diaphragm support (9) and diaphragm spacer(s) (10)
off the threaded portion of the diaphragm (8) and retain them.
5. Check that all parts are free from dirt and clean them if neces-
sary (see chapter 6. Cleaning).
6. Put the diaphragm support (9) and diaphragm spacer(s) (10),
in that order, on the threaded portion of the new diaphragm (8).
7. Screw the new diaphragm (8) complete with diaphragm sup-
port (9) and diaphragm spacer(s) (10) into the connecting rod
(clockwise) and tighten it by hand.
Changing the valve plates/sealings
1. Remove the valve plates/sealings (7) from the intermediate
plate (2)
2. Check that the valve seats, intermediate plate (2) and head
plate (fig. 7/3) are clean. If scratches or distortion are evident
on these parts they should be replaced.
3. Lay the new valve plates/sealings (7) in the recesses in the
intermediate plate (2). The valve plates/sealings for suction
and pressure sides are identical, as are upper and lower sides
of the valve plates/sealings.
4. Check that the valve plates/sealings (7) are not deformed by
moving them gently sideways in their recesses.
5. Dispose of the old diaphragm and valve plates/sealings
properly.
Refitting pump head
1. Place the intermediate plate (2) with valve plates/sealings (7)
on housing (1) in the position indicated by the drawing line.
2. Place the head plate (fig. 7/3) with cover (fig. 7/5) on the inter-
mediate plate (2) in the position indicated by the drawing line.
3. Check that the head plate (fig. 7/3) is centred by moving it
gently sideways.
4. Tighten the screws (4), evenly and diagonally, first gently, then
firmly.
Servicing
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