KNF Laboport N86 KN.18 Mode D'emploi page 46

Servicing
Fig. 5: Removing pump head
Fig. 6: Pump head
18 Translation of original Operating Instructions, English, KNF 121435-121438 04/18
Health hazard due to dangerous substances
in the pump!
Depending on the substance transferred, caustic
burns or poisoning are possible.
WARNING
 Wear protective clothing if necessary, e.g.
protective gloves.
 Flush pump before replacing the diaphragm and
valve plates (see chapter 8.2.1).
Removing pump head
1. Mark the position of head plate (Fig. 5/3), cover (5) and
cover plate (6) by a drawing line with a pencil. This helps
to avoid incorrect assembly later.
2. Undo the 4 screws (4) in the head plate (3) and lift the
head plate together with cover (5) off the pump housing.
3. Mark the position of intermediate plate (fig. 6/2) and
housing (1) relative to each other by a drawing line with
a pencil.
4. Lift intermediate plate (2) off the housing (1).
Change diaphragm
1. Using a small screwdriver, between the housing (1) and
the outer edge of the diaphragm (9), carefully lever the
edge of the diaphragm lightly upwards
2. Grip the diaphragm (9) on opposite sides, unscrew it
about two turns (anti-clockwise).
3. Hold the pump with one hand, so that the head is point-
ing downwards. Turn the diaphragm (9) anti-clockwise to
unscrew it.
4. Take the diaphragm support (10) and diaphragm spac-
er(s) (11) off the threaded portion of the diaphragm (9)
and retain them.
5. Check that all parts are free from dirt and clean them if
necessary (see chapter 6. Cleaning).
6. Put the diaphragm support (10) and diaphragm spacer(s)
(11), in that order, on the threaded portion of the new di-
aphragm (9).
7. Screw the new diaphragm (9) complete with diaphragm
support (10) and diaphragm spacer(s) (11) into the con-
necting rod (clockwise) and tighten it by hand.
Mini Laboratory pumps N 86.18, N 811.18