Powers 593 Series Flowrite II Heavy Duty Bronze Globe Control Valves - Manual (Page 4)

4
CHANGING SPRINGS (DIRECT ACTING ACTUATORS)
Springs can be changed or added if a higher shutoff rating is
required. This may become necessary under the following
conditions:
1. If the pressure of the medium passing through the valve increases,
2. If the valve size increases due to an increase in process demand, or
3. If valve body type is changed.
The Modification Data Tables (page 13-15) provide dimensional
data including part numbers, and number of springs required to
reconfigure an actuator.
Springs may be changed with the actuator assembled or removed
from the valve. For ease of instruction, pictures are shown with
actuators removed.
To change or add springs on a Direct Acting (DA, NO, ATC)
actuator assembled to the valve, follow steps 1, 2, 3, 4A, 5-10.
To change or add springs on a Direct Acting (DA, NO, ATC)
actuator removed to the bench, follow steps: 1-4A, 5-9.
To change or add springs on a Direct Acting (DA, NO, ATC)
actuator assembled to the valve and under preload, follow steps:
1, 3, 4B, 5-10.
1. Shut off controlled medium supply (steam, water, or other
liquid).
2. Reduce preload on the springs (refer to Decreasing Preload
on DA Actuators pg. 7).
3. Remove the control signal to the actuator.
4A. (Fig. 1) Remove top housing nuts and bolts or (see above)
4B. (Fig. 1) Remove the three bolts attached to the short nuts,
then equally release the bolts attached to the long nuts.
CAUTION: Springs under tension.
5. (Fig. 2A) Remove upper housing.
6. Remove stem nut, silver and black washers (Fig. 2B).
7. Remove diaphragm, and thrust plate (Fig. 2C).
8. Change or add springs as needed (Fig. 3A & 3B). Make sure
the springs are properly placed over the spring guides
and their configuration is symmetrical.
9. Reassemble parts in reverse order, then attach upper housing.
10. Adjust preload ref.
NOTE: Some actuator models have small springs nested inside
the larger springs. The small springs also fit over spring guides
and must also be placed symmetrically.
Fig 1 - Remove Housing Bolts
*(extended versions last and gradually) Fig 2A - Remove Upper Housing Fig 2B - Remove Stem Nut, & Washers
INSTALLING AN ACTUATOR
1. Place actuator assembly over valve stem. With actuator stem and
valve stem separated, place bonnet lock nut over valve stem onto
bonnet.
2. Apply air pressure to the actuator approximately 9 psi for a
Normally Closed valve assembly, and 3 psi for a Normally Open
Assembly.
3. Tighten the valve stem to the actuator stem by rotating the valve
stem (NOT THE ACTUATOR STEM).
4. Tighten the two locknuts together and rotate them clockwise.
Tighten the nuts to achieve the proper PRELOAD (as explained in
the Preload Section).
5. Remove air pressure.
6. Tighten the bonnet locknut on the bonnet (Fig.1).
Fig 1 - Tighten the Bonnet
Lock Nut on the Bonnet