3 Maintenance
Always use Alfa Laval genuine spare parts.
3.5
Type 10, 20, and 30 Actuator
INTRODUCTION
This section covers servicing of the following actuators: Type 10L - 10S (normally open), Type 20L - 20S (Normally Closed) Long
and Short, and Type 30L - 30S (Air Both Ways).
The 10 and 20 actuators are identical; with spring return operation. The change in description is for describing the mode of
operation when coupled to a valve. “10” defines normally open (air to lower) and “20” defines normally closed (air to close)
operation, but physically they are the same. Type 30 is a double acting actuator that is identical to the 10/20 except it does not
contain a spring. These actuators will require minimum maintenance over many years of service.
IMPORTANT:
Additional air supply must be relieved when product pressure is not present. Failure to do so will result in pressure damage
to the seat.
When using additional air loading it should exceed the minimum required by no more than 3 to 5 psig.
Valve Size
*Add’l Air
Pressure
Add’l Air
Pressure
Maximum
Maximum
Product
Holding
Pressure
1
1
10
200
1 1/2
1
5
200
2
2
10
150
2 1/2
3
20
100
3
3 1/2
35
100
4h
5
30
100
4
15
60
100
WARNING
To prevent personal injury, do not attempt to cut the actuator open. The
actuator spring is compressed and under load.
Air pressure measured in psig.
*Additional air pressure required to hold against 10
psig product pressure.
INSTALLATION
Connect air supply to the 1/8-27 FNPT port(s) located on the green end cap or yoke. Air supply specifications: 60 to 80
psig for spring return (Type 10 & 20); 35 psig for double acting (Type 30). Refer to table at right if additional product holding
pressure is required on normally closed Type 20 actuators.
Bushing/Packing Replacement
Bushings guide the actuator stem while packings provide sealing around the stem. The bushing and packing should both be
replaced if one or the other fails. Even if only one end fails both ends of the actuator should be serviced. Disconnect and remove
actuator completely from valve before proceeding with the steps that follow, see Valve Disassembly.
Step 1
Remove end cap from actuator. Separate clear stem protector
from the end cap. Fasten the end cap without stem protector to
one end of the actuator.
CAUTION
To prevent personal injury, keep hands and tools out of and away
from valve bodies and stems when applying or releasing air to an
actuator. The actuator stem assembly moves with extreme force
and suddenness.
CAUTION
To prevent personal injury, do not attempt to remove the bushing
or packing without the endcap fastened to the actuator. The
packing and bushing will be forced out of the actuator under air
pressure and will be trapped by the end cap.
Air
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Summary of Contents for 741 Series
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