13
The different methods of arranging the discs are dependent on the type of valve. Three different methods are
possible:
A: Arrangement for a through-valve with "Valve stem retracting" as direction of closing (Figure 9).
B: Arrangement for a 3-way valve (Figure 9).
C: Arrangement for a through valve with "Valve stem extending" as direction of closing (Figure 9).
3-way valves using the spring disc arrangement "B" require only half of the spring stroke
designated in the spring pressure graph below!
Basic rule:
For a through-valve, first set the CLOSED position force/stroke-dependent, then the OPEN position stroke-
dependent.
For a 3-way valve set both limit positions force/stroke-dependent.
9.3.2 Force/Stroke-Dependent Limit Switch Cut-Off
Using the handwheel on the actuator, drive the valve into the limit position until the valve cone touches the
valve seat. This occurs when the valve stem nut starts to move axially and the spindle pushes against the disc
spring force.
Mark the position on one of the drive support pedestals at the rotation protection piece.
Continue to drive the actuator in the same direction until the disc springs are compressed to the required
amount (see the specific data sheet for the drive) as denoted on the spring/force diagram.
Unlock the fixing screw on the corresponding switching cam (Figure 8), move the cam towards the limit switch
until it clicks, and re-tighten the fixing screw.
Check the setting by repeating the drive action to close the valve and check that the spring discs are compressed
to the correct stroke. Re-adjust the cam if required.
Figure 10: Spring load graph PSL320 Figure 11: Spring load graph PSL325-330
9.3.3 Stroke-Dependent Limit Switch Cut-Off
The spring discs are not compressed for the stroke dependent limit switch cut-off.
Using the handwheel of the actuator, drive the valve until the required end position is reached.
Unlock the fixing screw on the corresponding switching cam (Figure 8), move the cam towards the limit
switch until it activates, and re-tighten the fixing screw.
Check the settings by driving into the end position again and measure the valve stroke. Re-adjust the cam if
required.
a = for
arrangement A
and C
b = for
arrangement B
a = for
arrangement A
and C
b = for
arrangement B
To Next Page
Loading...