Type 657 Sizes 80 & 100
10
decrease damping action. The adjusting screw on the
right (the lower of the two adjusting screws in section
B-B of figure 7) regulates downward damping action,
and the screw on the left regulates upward damping
action.
Size 80 Top-Mounted Handwheel
CAUTION
If repeated or daily manual operation is
expected, the actuator should be
equipped with a side-mounted hand-
wheel rather than a casing-mounted
travel stop or top-mounted handwheel.
The side-mounted handwheel is de-
signed for more frequent use as a manu-
al operator.
A top-mounted handwheel assembly is normally used
as an adjustable-up travel stop to limit full retraction of
the actuator stem. Turning the handwheel clockwise
turns the handwheel stem (key 133, figure 8) into the
diaphragm casing and forces the pressure block as-
sembly (key 179, figure 8) against the diaphragm and
diaphragm plate. Instructions are given below for com-
plete disassembly and assembly. Perform the disas-
sembly only as far as necessary to accomplish the
required maintenance; then, begin the assembly at the
appropriate step.
Key numbers refer to figure 5 for actuator parts and
figure 8 for handwheel parts.
Size 80 Top-Mounted Handwheel:
Disassembly
1. Bypass the control valve. Reduce the loading pres-
sure to atmospheric, and remove the tubing or piping
from the diaphragm casing (key 1).
WARNING
To avoid personal injury from the pre-
compressed spring force thrusting the
upper diaphragm casing (key 1) away
from the actuator, relieve spring com-
pression (step 2, below), and carefully
remove casing cap screws (key 141)
(step 3, below).
2. Remove cover band (key 60). Insert a rod of
approximately 1/2-inch (12.7 mm) diameter into a hole
in the adjusting screw (key 12), and rotate the adjust-
ing screw from right to left until spring compression is
relieved. Rotate handwheel to be sure it is not com-
pressing actuator spring.
3. Unscrew cap screws (key 141), and remove hand-
wheel assembly.
4. Remove hex nut (key 54), and lift off the hand-
wheel.
5. Unscrew support screws (key 182), and remove
pressure block, stem, stem collar, and thrust bearing
(keys 179, 133, 183, and 175).
6. Unscrew body nut (key 186), and remove gland
(key 180). If necessary, remove and replace packing
rings (key 181).
Size 80 Top-Mounted Handwheel:
Assembly
1. Install new packing rings and gland (keys 181 and
180), and thread the body nut (key 186) onto the body.
2. Lubricate the thrust bearing and stem (keys 175
and 133), with Lubriplate MAG-1 (key 241) or equiva-
lent lubricant. Slide stem, stem collar, thrust bearing,
and pressure block (keys 133, 183, 175, and 179) into
the body as shown in figure 8. and install support
screws (key 182).
3. Install handwheel and hex nut (keys 51 and 54).
4. Install a new handwheel gasket (key 185).
5. Mount the handwheel assembly on the diaphragm
casing, and secure with cap screws (key 141).
6. Reconnect pressure tubing or piping to actuator
casing.
Size 100 Top-Mounted Handwheel
A top-mounted handwheel assembly is normally used
as an adjustable-up travel stop to limit full retraction of
the actuator stem. Clockwise rotation of the hand-
wheel (key 51) moves the actuator stem (key 10)
downward, compressing the spring (key 6). Spring ac-
tion returns the stem as the handwheel is turned coun-
terclockwise. Instructions are given below for complete
disassembly and assembly. Perform the disassembly
only as far as necessary to accomplish the required
maintenance; then, begin the assembly at the ap-
propriate step.
Key numbers refer to figure 6 for actuator parts and
figure 9 for handwheel parts.
Size 100 Top-Mounted Handwheel:
Disassembly
1. Bypass the control valve. Reduce the loading pres-
sure to atmospheric (refer to the
Maintenance sec-
tion), and remove the tubing or piping from the dia-
phragm casing.