ProMinent Makro TZ Operating Instructions Manual page 18

Function description
Page 18
Description of the liquid end function
The TZHa liquid end has a hydraulically actuated displacement element in the form of a highly
durable composite diaphragm (2). It hermetically seals the feed cavity in the liquid end (3) and
creates the displacement action within the liquid end at each pump stroke. The suction valve (4)
and the discharge valve (1) together with the diaphragm action perform the feed process.
As the diaphragm is hydraulically actuated – it is permanently connected to the piston (7) – it is
always pressure-compensated and is therefore suitable for high feed pressures.
As with a conventional motor-driven metering pump the motor moves the piston (7) forwards and
backwards. As it moves forwards the piston pushes in the hydraulic end and increases the
pressure in the hydraulic oil. The hydraulic oil then pushes the composite diaphragm (2) towards
the liquid end (3).
The stroke length of the composite diaphragm is adjusted by altering the stroke length of the
connecting rod.
The bleed valve (10) vents the hydraulic end and passes the gas bubble with a small amount of
oil into the storage tank (8). In this way the quantity of hydraulic oil in the hydraulic end decreases
and the composite diaphragm (2) moves slowly towards the piston (7). When contact with the
diaphragm position sensor (5) is made, the compensation valve (6) opens and hydraulic oil is
sucked out of the storage tank, thereby correcting the diaphragm position.
1
2
3
4
Fig. 12 TZHa function
10
5
A B
9
7 8
6
A Liquid end
B Hydraulic end
1 Discharge valve
2 Composite diaphragm
3 Liquid end
4 Suction valve
5 Diaphragm position sensor
6 Compensation valve (snifting valve)
7 Piston
8 Feed tank
9 Overpressure sensor
10 Bleed valve
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