Pneumatic Diaphragm Actuator Type S57 And S67

I. Overview

 

Balanced by a spring, the pneumatic diaphragm actuator (Fig. 1) type S57 and S67 can respond to the pneumatic output signals sent by valve positioner to the actuator diaphragm, and determine the position of valve element on basis of signal variation. The actuator's zero position and stroke range is determined by compression and rigidity of spring respectively.

Actuators type S57 and S67, which are featured by direct action and reverse action respectively, are designed for opening, closing or regulating the adjustment valves with high reliability.

See Fig. 1 for installation example of pneumatic actuator.

Fig. 1 Installation Example of
Pneumatic Actuator Type S57

II. Specification (see Table 1)

Table 1 Specification

S67-30~S67-87 Fig. 2 S57-30-S57-87

III. Characteristics

1. High adaptability: We can offer actuators from 2 major series and 10 specifications and fitted with sorts of springs, stroke limiters and manual operators, to be adaptable to almost all control valves.

2. Superior linear relationship between load pressure and stroke: By moving inside the deep diaphragm shell, the diaphragm enjoys the minimum area change in the entire stroke.

3. High dynamic stability and frequency response: Fast response benefited from small chamber volume.

4. Resistant to large thrust: The diaphragm for die pressing can generate the maximum thrust under the given diaphragm size.

5. Long life: Solid and thick cast iron and cast steel structure contribute to high stability and avoid deformation due to overpressure; surface coating is resistant to corrosion.

6. Applicable to low-temperature workplace: All Type S57 and S67 pneumatic diaphragm actuators are given performance improvement to ensure normal functioning below -50℃. It is recommended to install positioner to keep good response under -40℃.

7. Rigid connection: Connected by split push-rod connector, the actuators can enjoy reliable transmission, easy installation and avoid lost motion and inaccurate positioning of valve.

IV. Configuration Available

Direct action

As a direct action diaphragm type actuator, the actuator type S57 drives the push rod downwards when applied with air pressure onto the upper diaphragm shell. When this air pressure reduces, the actuator push rod will move upwards under reverse spring force, or the spring will ascend the actuator push rod to the topmost position when air source is cut off, so as to realize gas-loss opening for valve which is closed by pushing it downwards.

Reverse action

As a reverse action diaphragm type actuator, the actuator type S67 drives the push rod upwards when applied with air pressure onto the lower diaphragm shell. When this air pressure reduces, the actuator push rod will move downwards under the spring force, or the spring will descend the actuator push rod to the bottommost position when air source is cut off, so as to realize gas-off closing for valve which is closed by pushing it downwards.

Accessories

Handwheel

Designed as an adjustable stroke limiter, the handwheel of pneumatic diaphragm actuator can be urgently used for valve opening/closing and regulation in case of emergency. The actuator with side-mounted handwheel is recommended in places where valves are repeatedly handled manually each day.

Top-mounted handwheel

The handwheel of actuator type S57 and S67 is designed for setting the stroke limit at up and down direction respectively.

The handwheel of actuator Type S57 will move the actuator push rod downwards to compress the spring if being rotated clockwise, or it will push back the push rod under the action of spring if being rotated anticlockwise. While the handwheel of Type S67 actuator will move push rod upwards when being rotated anticlockwise, or rotate push rod downwards under the action of spring if being rotated clockwise.

Side-mounted handwheel

The side-mounted handwheel, which applies to the Actuators type S57 and S67 sized 34-87 instead of those sized 30, can be used at any point on stroke of actuator push rod in order to move the valve upwards or downwards. Different from the top-mounted handwheel, the side-mounted handwheel can be located at both upward/downward directions in order to limit the stroke; however, it cannot limit position at two directions simultaneously. The pneumatic action can be executed within the full stroke of valve when handwheel is rotated to the middle position, or valve stroke will be limited if handwheel stays at other position. The handwheel is fitted with a spring-loaded spherical brake to avoid setting change due to vibration.

Model Coding Rules

See Table 1 for Stroke and Spring Range

Manual mechanism: Marked as S if fitted with top-mounted manual mechanism

Marked as Sc if fitted with side-mounted manual mechanism

No mark if manual mechanism is unavailable

Specification of actuator: 30, 34, 40, 45, 46, 50, 60, 70, 70-4 and 87

Actuator code: S57 for direct action, S67 for reverse action

For example: Model: S57-40-S 29mm 0.04-0.2MPa

Meaning: Direct action actuator, sized 40, with stroke of 29 mm, spring pressure range is 0.04-0.2Mpa, fitted with top-mounted manual mechanism

Table 2 Other Technical Parameters of Type S57 and S67 Pneumatic Diaphragm Actuator

Table 3 Volume and Displacement for Diaphragm Shell of Actuators type S57 and S67

Table 4 Thrust in Corresponding Input Signals Range (Standard Signals)

Table 5 Technical Parameters of Manual Actuator Type S57

Table 6 Technical Parameters of Manual Actuator Type S67

VI. Dimensions

               Type S57                                            Type S67                        Type S57/67-87      

Type 34-60 Side-mounted Handwheel Type 70/87 Side-mounted Handwheel

Fig. 3

Table 7

Note: ①The figure above oblique line is 19 mm stroke, while the figure below oblique line is 29 mm stroke.

②The figure above oblique line is signal range 0.02-0.1MPa, while the figure below oblique line is signal range 0.04-0.2MPa.

VII. Selection of Actuator

1. Selection of Type S57 and S67: Choose Type S857 if actuator push rod needs to move upwards after gas source is cut off;
2. Choose Type 867 if actuator push rod needs to move upwards after gas source is cut off.
3. Connection method: Fasten the lock nets at the internal positioning holes of joint of bracket 30-70; Type 87 is connected via bolts, see table of dimensions for details.

VIII. Installation and Adjustment of Actuator:

1.Keep the push rod of actuator concentric with the valve rod while installing the actuator and valve together; otherwise, the push rod and upper diaphragm of actuator type S57 are tilted and thus affecting the stroke and service life of actuator; however, the Type S67 actuator is well protected against the problem above and free from accelerated wear of O-ring between push rod and sleeve, in order to avoid leakage.

2.The actuator, which is adjusted after delivery, should be readjusted after assembly by user and valve team:

a.Check if the seal of upper/lower diaphragm shell of Type S57 actuator has air leakage;

b.Check if air leakage occurs at the seal of upper/lower diaphragm shell and the joint

between push rod and sleeve of actuator type S67.

IX. Assembly & Disassembly of Actuator:

Type S57:

1. Loosen the screws on push rod connector to remove the connector.
2. Rotate spring-loaded governor anticlockwise until it is removed from bracket and spring is not bearing force.
3. Remove the hexagon head screws and nuts on diaphragm shell to uplift the diaphragm shell.
4. Remove the actuator diaphragm.
5. Remove the upper diaphragm shell, actuator guide rod and cap screw and keep them as independent component. If necessary, remove the head screws to further disassembly this component.
6. Remove actuator spring and spring seat.
7. If necessary, loosen the head screws on lower diaphragm shell to separate the bracket from the lower diaphragm shell.
8. Remove the spring-loaded governor from the bracket.
9. Check if parts are damaged and replace them if so. Clean the parts, apply lubricant at the joint and assemble according to the reverse procedure of disassembly.
10. Once parts are assembled, feed gas source, check if actuator is running normally and check the sealing of joints by using foaming agent.

Type S67:

1. Loosen the screws on push rod connector to remove the connector.
2. Rotate spring-loaded governor anticlockwise and remove it from pull rod. Uplift the spring seat and spring to remove them from the bracket.
3. Remove the hexagon head screws and nuts on diaphragm shell to uplift the diaphragm shell.
4. Remove the following components: Diaphragm, upper diaphragm, stroke block positioning ring, head screw, lower diaphragm and actuator push rod. Be careful when pulling out actuator push rod from sleeve to avoid damaging the O-ring.
5. Remove the head screws to take down the parts above.
6. Remove the check ring and uplift sleeve to remove the sleeve. Test the O-ring and replace it if necessary.
7. If necessary, loosen the head screws on lower diaphragm shell to remove the bracket and sealing gasket.
8. Check if parts are damaged and replace them if so. Clean the parts, apply lubricant at the joint and assemble according to the reverse procedure of disassembly.
9. Once parts are assembled, feed gas source, check if actuator is running normally and check the sealing of joints by using foaming agent.

X. Assembly & Disassembly of Top-mounted Handwheel:

Type S57:

1. Rotate the handwheel anticlockwise to avoid spring compression in any form.
2. Connect bypass of control valve, release loading pressure to air and dismantle the pipe or hose on handwheel rack.
3. Remove the hexagon head screws and nuts on diaphragm shell to uplift the diaphragm shell and handwheel component.
4. If necessary, separate the handwheel and diaphragm shell by removing the hexagonal head screw and O-ring must be replaced.
5. Loosen lock nut, rotate handwheel anticlockwise, remove nut and baffle ring and uplift the handwheel.
6. Loosen nut on manual bar and screw off the manual bar from bottom of handwheel rack.
7. Reinstall O-ring on the handwheel rack.
8. For handwheel components used on actuator sized 30 and 60, screw off the manual bar from push board directly to complete the disassembly process.
9. For handwheel components used on actuator sized 70, loosen the screws on push board and remove the thrust bearing to complete the disassembly process.
10. Check if parts are damaged and replace them if so. Clean the parts, apply lubricant on the handwheel, thread, bearing and check ring before assembling them according to the reverse procedure of disassembly.

Type S67:

1.Connect bypass of control valve, release loading pressure to air and dismantle the pipe or hose at top of bracket.

2.Rotate the handwheel clockwise to avoid spring compression in any form.

3.Rotate the spring-loaded governor of actuator to release the compression of spring completely.

4.Do maintenance of needle roller thrust bearing, thrust washer and manual bar by the following steps:

• Remove the handwheel cover to take down elastic cylindrical pin. Remove the nut, baffle ring, needle roller thrust bearing and thrust washer.
• Remove the manual bar from handwheel rack by using the handwheel.
• Remove the manual bar if necessary. The manual bar can be reserved without removal in most of the maintenance process.
• Clean and inspect all parts and replace them if necessary. Apply lubricant or equivalent on handwheel, thread and bearing when reassembling the parts.
• Apply lubricant on manual bar, install it in handwheel, apply lubricant on baffle ring, needle roller thrust bearing and thrust washer when assembling them. Install and fasten the nuts and insert them in the elastic cylindrical in. Reinstall the handwheel cover.

5.Handwheel of actuator sized 30-60:

• Remove the bolts and make sure guide plate can rotate smoothly between handwheel rack and connection flange.
• Remove handwheel cover and elastic cylindrical pin, remove nut, and screw off the manual bar if necessary; remove the handwheel bar and connected parts.
• Screw off hexagon nuts and hexagonal head screws from diaphragm shell, uplift diaphragm shell and connection flange.
• If necessary, do other maintenance of actuator before assembly.

6.Handwheel of actuator sized 70:

• Remove handwheel cover, take out elastic cylindrical pin, nut, baffle ring, needle roller thrust bearing and thrust washer; now, the manual bar can be reserved without removal.
• Remove hexagon nuts and hexagonal head screws from diaphragm shell, uplift the diaphragm shell, handwheel rack and connected parts.
• Where stop screws are used, record their relative position to the bolts for handling in assembly process. Remove the stop screws and hexagonal head screws, take down connection flange, handwheel rack and connected parts.
• Rotate handwheel, remove manual bar from handwheel rack. The baffle ring needs to be removed to separate the handwheel and manual bar.
• If necessary, do other maintenance of actuator before assembly.

Type S57 Manual Mechanism      Type S67 Manual Mechanism

Fig. 4

XI. Assembly & Disassembly of Side-mounted Handwheel:

Side-mounted manual mechanism sized 34~60

1. If necessary, remove the handwheel from actuator bracket and remove the U-bolt and nut.
2. Remove the fixed ring and take out bar split pin.
3. Remove the left/right bar screws and take down bar from component.
4. Remove the screws of stroke mark and pointer.
5. Remove lock nut, gasket and take down handwheel; do not lose the rolling ball and spring.
6. Loosen bearing holder using proper tools.
7. Uplift the screws from handwheel and nuts will be pulled out simultaneously; remove the sleeve.
8. If necessary, remove the two bearings which are separately located at the bearing holder and handwheel.
9. Check if parts are damaged and replace them if so. Clean the parts, apply lubricant or equivalent on the handwheel, thread and bearing before assembling them according to the reverse procedure of disassembly.

Side-mounted manual mechanism sized 70-87

Type S57:

1. Connect bypass of control valve, release loading pressure to air and dismantle the pipe on handwheel rack.
2. Rotate spring-loaded governor anticlockwise and release the spring.
3. Remove screw and nut, uplift diaphragm shell and remove the diaphragm.
4. Remove the connection screws and diaphragm plate.
5. Remove spring, upper lining and sparing seat from bracket cylinder.
6. Remove push rod connector to take out the actuator push rod and stroke indicator.
7. Rotate handwheel, uplift screw rod until it is separated from worm gear pair.
8. Loosen 2 set screws, loosen the bearing holder flange and spring-loaded governor, take out worm gear pair and thrust bearing.
9. Remove spring-loaded governor from bearing holder flange. If necessary, remove the worm shaft and relevant parts for replacement and lubricating. Remove the lock nut and handwheel firstly and do not lose the rolling ball and spring.
10. Loosen 2 set screws and loosen front/rear holder, to screw off bearing and holder together and remove the worm shaft.
11. Check if parts are damaged and replace them if so. Clean the parts, apply lubricant or equivalent on the handwheel, thread and bearing before assembling them according to the reverse procedure of disassembly.

Type S67:

1. Connect bypass of control valve, release loading pressure to air and dismantle the pipe on handwheel rack.
2. Rotate spring-loaded governor anticlockwise and release the spring.
3. Remove screw and nut and uplift diaphragm shell.
4. Remove stroke block screw, locating ring, diaphragm plate, diaphragm and lower diaphragm plate.
5. Loosen screws, remove the lower diaphragm shell and spring adapter.
6. Remove the baffle ring, take out sleeve and O-ring from spring adapter.
7. Remove actuator spring.
8. Remove push rod connector and screw.
9. Uplift actuator push rod (push rod and spring adjusting screw), remove spring seat, spring adjuster and bearing.
10. Rotate handwheel to stretch the lower lining out of bracket bottom.
11. Loosen 2 set screws, loosen the bearing holder flange and spring-loaded governor, take out worm gear pair and thrust bearing.
12. If necessary, remove the worm shaft and relevant parts for replacement and lubricating. Remove the lock nut and handwheel firstly and do not lose the rolling ball and spring.
13. Loosen 2 set screws and loosen front/rear holder, to screw off bearing and holder together and remove the worm shaft.
14. Check if parts are damaged and replace them if so. Clean the parts, apply lubricant or equivalent on the handwheel, thread and bearing before assembling them according to the reverse procedure of disassembly.

Fig. 5 Side-mounted Manual Mechanism Sized 30-60

Side-mounted Manual Mechanism S57Sc-70 Side-mounted Manual Mechanism S67Sc-70

Fig. 6

XII. Order Instructions:

1.Please clearly mark the following contents when placing an order:

1)Actuator model, specification, stroke, spring range and gas source pressure;

2)Actuator accessories.

2.Any special requirements must be clarified before you place an order:

1)Special stroke of actuator;

2)Actuator will be operating in low/high-temperature places;

3)Actuator will be operating in places with salt wind, chlorine and corrosion;

4)Technical supports need to be provided by us.

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