Dwyer WE02 - Manual (Page 4)

PNEUMATIC ACTUATOR
Note: For optimal operation, pneumatic actuators should be run with a supply of
clean, lubricated air.
Spring Return Actuator Operation
Air to PORT 2 (the left hand port) causes the actuator to turn counter clockwise
(CCW). Loss of air to PORT 2 causes air to exhaust and the actuator turns
cockwise (CW). This is the FAIL CLOSE operation.
Double Acting Actuators Operation
Air to PORT 2 (the left hand port) causes the actuator to turn counter clockwise
(CCW). Air to PORT 1 (the right hand port) causes the actuator to turn clockwise
(CW).
Pneumatic Actuator Maintenance
Routine maintenance of pneumatic actuator:
• Keep the air supply dry and clean
• Keep the actuator surface clean and free from dust
• Periodic checks should be done to make sure all fittings are tight
• Pneumatic actuators are supplied with lubrication to last the entire life span of the
actuator under normal operating conditions.
The outer surface of the pneumatic actuator should be clean to avoid friction or
corrosion. All fittings and connections should be tight to prevent leaks during
operation. Check the bolts mounting the valve to the actuator to make sure they
have not come loose during shipping or installation. Make sure the valve and
actuator are not rubbing or jamming against other components during operation.
The actuator should be inspected annually to make sure all fittings and bolts are
tight and nothing has come loose during operation.
Disassembling Pneumatic Actuators
Failures
Pneumatic
actuator won’t
operate
Pneumatic
actuator runs
slowly
Inspection Items
1. Check the solenoid valve. Is
the coil burnt out or is the
solenoid spool?
2. The actuator will not move
because of debris in the gears.
3. The pneumatic line to the
actuator is distorted or
smashed.
4. The pneumatic line is frozen
because of low temperatures
and moisture.
1. The air supply pressure is
insufficient.
2. Are other pneumatic devices
consuming the air required for
the actuator to operate?
3. The pneumatic actuator is
undersized for the application.
Corrective Action
1. Replace the solenoid
valve coil or remove debris.
2. Disassemble the actuator,
clean the debris and
reassemble the actuator.
3. Replace pneumatic line to
the actuator.
4. Warm the pneumatic lines
and remove moisture from
supply lines.
1. Increase the air supply
pressure and look for leaks
in the supply pressure
pipeline.
2. Increase the air supply or
reduce the number of
devices operating at the
same time.
3. Replace the actuator with
a larger actuator.
Page 4
Before beginning disassembly, ensure that the air supply to the
actuator has been disconnected, all accessories have been
removed, and that the actuator has been disassembled from the valve.
1. Loosen the end cap fasteners (22) with a wrench (size varies depending on
actuator model). On the spring return actuator, alternate 3 to 5 turns on each
fastener until the springs are completely decompressed. Use caution when
removing the cap since the springs are under load until the fasteners are fully
extended.
2. Remove the pinion snap ring (10) with a lock ring tool. The indicator (7) may now
be removed.
3. Turn the pinion shaft (2) counter clockwise until the pistons are at the full end of
travel. Disengage the pistons (11) from the pinion. (NOTE: Low pressure air--3 to 5
psi MAXIMUM--might be required to force the pistons completely from the body.)
Note the position of the pistons before removing them from the actuator body.
4. Remove the pinion through the bottom of the actuator. The actuator is now
completely disassembled.
Pneumatic Actuators Bill of Materials
WARNING
Be sure the actuator surfaces are free of debris and scratches
before reassembling.
1. Apply a light film of grease to all O-rings and the pinion before replacing.
2. Put the pinion (2) back through the actuator with the flats of the pinion shaft
running parallel with the body.
3. When reassembling the actuator, make sure that the piston racks are square to
the actuator body and returned to their original orientation. (NOTE: The normal
operation of all spring return pneumatic actuators is FAIL CLOSED. To change the
orientation to FAIL OPEN, rotate the racks 180º to create a reverse operation.
4. When replacing springs in a spring return actuator, ensure that the springs are
replaced in their identical position in the end cap from which they were removed.
(NOTE: In some circumstances, you might want to change the standard 80 pound
spring set to fit your application and available air pressure.
5. Seal the end caps with a petroleum lubricant and bolt to actuator body.
6. Check the seal of the actuator by covering seal areas (pinion, end caps) with
soapy water and using low pressure air to the actuator to ensure that no bubbles
are produced.
WARNING
Part Number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
Quantity
1
1
1
1
1
1
1
1
1
1
1
1
1
4
2
2
2
2
5 to 12
2
1
1
8
2
2
2
2
Part Name
Cylinder
Output Shaft
O-ring
Bearing
Adjusting Cam
Thrust Bearing
Bearing
O-ring
Bearing
Gasket
Damping Ring
Position Indicator
Screw
Position Indicating
Inserts
Piston
Guide Ring
O-ring
Guide Ring
Spring Assembly
O-ring
Left End Cap
Right End Cap
End Cap Bolt
O-ring
Gasket
Nut
Adjusting Bolt Material
Extruded Aluminum Alloy
Stainless Steel
Fluorine Silicon Rubber
Nylon46
Stainless Steel
Nylon46
Nylon46
Fluorine Silicon Rubber
Nylon46
Stainless Steel
Stainless Steel
PPPP+30%GF
PPPP+30%GF
PPPP+30%GF
Casting Aluminum Alloy
Nylon46
Fluorine Silicon Rubber
Fluorine-Carbon Composite Material
Alloy Spring Steel
Fluorine Silicon Rubber
Casting Aluminum Alloy
Casting Aluminum Alloy
Stainless Steel
Fluorine Silicon Rubber
Stainless Steel
Stainless Steel
Stainless Steel
Reassembling Pneumatic Actuators