KNF Laboport N811 KN.18, Operating Instructions Manual

Page: 47 / 140

Mini Laboratory pumps N 86.18, N 811.18 Servicing
Translation of original Operating Instructions, English, KNF 121435-121438 04/18 19
Changing the valve plates/sealings
1. Remove the valve plates/sealings (fig. 6/ 7 ) from the intermedi-
ate plate ( 2 ).
2. Check that the valve seats, the head plate ( 3 ) and intermediate
plate ( 2 ) 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 the housing, in the position indicated by the drawing line.
2. Place the head plate ( 3 ) with cover (fig. 5/ 5 ) on the housing
(fig. 6/ 1 ), in the position indicated by the drawing line.
3. Check that the head plate ( 3 ) is centred by moving it gently
sideways.
4. Tighten the screws ( 4 ), evenly and diagonally, first gently, then
firmly.
Final steps
1. Reconnect suction and pressure line to the pump.
2. Reconnect the pump to the electricity supply.
If you have any question about servicing call your KNF technical
adviser (see last page for contact telephone number).
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