6
Functional description
6.1 Liquid End
The dosing process is performed as follows: The diaphragm is
pressed into the dosing head; the pressure in the dosing head
closes the suction valve and the feed chemical flows through the
discharge valve out of the dosing head. The diaphragm is now
drawn out of the dosing head; the discharge valve closes due to
the negative pressure in the dosing head and fresh feed chemical
flows through the suction valve into the dosing head. One cycle is
completed.
6.2 Drive Unit
The diaphragm is driven by an electromagnet, which is controlled
by an electronic controller.
6.3 Capacity
The capacity is determined by the stroke length and the stroke
rate.
The stroke length is adjusted by the stroke length adjustment knob
within a range of 0 ... 100 %. A stroke length of between 30 ... 100
% (SEK type: 50 ... 100 %) is recommended to achieve the speci‐
fied reproducibility!
Data
Value Unit
Recommended stroke length,
standard type
30 ... 100 %
Recommended stroke length, SEK
type
50 ... 100 %
The stroke rate can be set within a range of 10 ... 100 % using the
multifunctional switch.
6.4 Self-Bleeding
Self-bleeding liquid ends (SEK types) are capable of independent
priming when a discharge line is connected and diverting existent
air pockets via a bypass. During operation they are also capable of
conveying away gases which are produced, independently of the
operating pressure in the system. It is also possible to dose pre‐
cisely in a depressurised state due to the integral back pressure
valve.
6.5 Operating modes
The operating modes are selected by means of the multifunctional
switch.
As soon as the stroke rate has been set by the multifunctional
switch, the pump finds itself in "Manual" operating mode. 100%
corresponds to 180 strokes/min.
"Manual" operating mode
Functional description
19
