172-65742MA-01 (CT20/CT20D) 7 Oct 2021
13
Instructions for Reverse Action (Air to Open, Fail Closed) Stroke Adjustment
1.
Make sure that the valve plug is securely seated in the valve seat. (Fig. 1)
2.
Supply the maximum air pressure (0.33 MPaG (48 psig, 3.3 barg)) of the spring
range (e.g. 0.09 to 0.33 MPaG (13 to 48 psig, 0.9 to 3.3 barg)) to the actuator.
(Refer to the nameplate, drawing or specification data sheet (SDS) for the spring
range.)
With the actuator stem raised, screw the locknut and stem connector nut into the
guide bushing as far as possible without touching the valve stem. (Fig. 2)
3.
Supply the lower limit air pressure (0.09 MPaG (13 psig, 0.9 barg)) of the spring
range (e.g. 0.09 to 0.33 MPaG (13 to 48 psig, 0.9 to 3.3 barg)) to the actuator.
The actuator stem will descend. (Fig. 3)
NOTE: Be careful not to pinch your fingers.
4.
Turn the stem connector nut until it comes into contact with the actuator stem,
and turn the stem connector nut a further 1/4 turn to contact the actuator stem.
Make sure that the valve plug is seated in the valve seat.
Hold the stem connector nut with a spanner and tighten the locknut with a
proper torque. (Fig. 4)
5.
Shut off the air supply to the actuator.
NOTE: Be careful not to pinch your fingers.
6.
Secure the stem connector nut and the actuator stem with the stem bracket
clamps. Make sure to adjust the stem bracket clamps to 0% (fully closed) on the
travel indicator scale. (Fig. 5)
Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Actuator Stem
Valve Stem
Locknut
Stem
Connector Nut
Actuator Stem
ascends
Actuator Stem
descends
NOTE:
Be careful
not to pinch
your fingers
Stem
Connector Nut
Locknut
Stem Bracket Clamps
Travel Indicator Scale
Travel Indicator Scale
Mounting Bolt
Travel Indicator Scale
Mounting Bolt
