18
4.1.2 PN9100R, PN9200R, PN9300R or PN9400R spring-retract actuators
only
Note: Adjustment of the spring will only alter the pressure of the control signal air at which
the valve commences to move off its seat (set point) and will not alter the spring pressure
range required to move the valve through its full travel. i.e. 0.2 to 1.0 bar spring (range
0.8 bar) set to commence to lift at 0.4 bar will require a 1.2 bar air pressure (0.4 + 0.8) to
obtain valve full travel.
To adjust the set point refer to Figure 3 and proceed as follows:
-
Ensure the control valve has been isolated and the actuator housing is pressure free.
-
Loosen and remove the clamp nuts and screws (26 and 27, see Figure 8) and remove
the valve adaptor (11).
-
Using two spanners whilst holding the actuator spindle (6) loosen the actuator connector
lock-nut (25).
-
Apply the control signal pressure required to complete the full travel of the actuator
spindle.
-
With the valve plug remaining on its seat adjust the valve adaptor (11) until it presses
tightly against the connector (10). See Figure 7 for correct installation.
Caution: Two female threads must be visible inside the adaptor when fitted to the valve
spindle.
-
Fit the front and rear clamps (13 and 14) across the collar (12) and valve adaptor (11).
-
Ensure that the screws (26) and the nut (27) are not damaged.
-
Fit the clamp locking screws and nuts (26 and 27) and loosely tighten. Operate the unit
over its full travel four times to ensure alignment. Tighten the locking screws and nuts
to 2 N m (1.5 lbf ft).
-
Release the air control pressure and recheck that the valve just commences to move
toward the seat at the right spring range (minimum pressure), and is fully closed at the
spring range (maximum pressure). After the test check the position of the scale travel
indicator against the 'arrow' of the connector and adjust its position accordingly.
Warning: To prevent damage to the valve seat, please ensure the plug does not turn while
pressing on the seat during assembling or adjustment. To prevent damage to the
diaphragm, ensure the actuator spindle (6) is not allowed to rotate when the
diaphragm is assembled within its housing.
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