November 2022
Installation, Operation and Maintenance Manual
MAC050515 EN Rev. 0
22
Bottom Mounted Stop Block
Section 11: Bottom Mounted Stop Block
11.3.3
Reverse Action Fail-Safe Counterclockwise
Air power between the pistons rotates the pinion in a clockwise direction.
When the air pressure is removed the springs drive the actuator pinion counterclockwise.
11.4
Actuator Conventions for the Normal Position
11.4.1
Double-Acting
For convention purposes the At Rest or NORMAL (CLOSED) position is when the pistons
are together. This is when the air power is supplied to the bottom port “4” next to the
solenoid mounting pad.
11.4.2
Spring-Return
On Spring-Return actuators, the NORMAL (CLOSED) condition is when no air pressure is
present and the pistons are together under the force of the springs.
11.5
Assembly to Valves for Standard
Rotation Configuration
11.5.1
Double-Acting and Fail-Safe Clockwise
1.
Make sure the valve is set in the CLOSED position if it is to Fail CLOSED and in the
OPEN position if it is to Fail OPEN.
2.
Assemble the mounting bracket to the valve with the open part of the bracket in
line with the direction of flow through the valve.
3.
Assemble the long shaft adaptor to the valve stem.
4.
Take the stop block assembly making sure the arrow cast into the quadrant is
facing toward the single indent on the top of the stop block assembly.
5.
With the quadrant held in this position, the pointed dowels (refer to Figure 8)
facing upwards and the stop bolts facing towards the closed side of the mounting
bracket, place the stop block assembly over the square drive shaft of the long shaft
adaptor onto the top face of the mounting bracket. The shallow recessis now on
the underside next to the bracket.
NOTE:
The dowel pins assembled with pointed end facing towards actuator bottom,
gives additional grip between actuator and stop block when securely fastened by the
mounting studs.
6.
Lower the actuator onto the adaptor, checking that the actuator is in the NORMAL
position (pistons together) with the solenoid mounting face towards you and
screw the four (4) fixing studs through the mounting bracket, through the stop
block into the actuator base (refer to Figure 9).
7.
Ensure that the studs are screwed into the actuator until they bottom in the hole.
8.
Fit washers and nuts onto the studs.
9.
Using a torque wrench, tighten the studs to a torque of 175 Nm (130 lbf-ft).
10.
Adjust the stop bolts to the desired position.
