Pneumatic Ledeen Actuators
Quarter-turn operation
Reliable performance with compressed air, natural gas, or nitrogen.
Dynatorque SD declutchable manual override
Enables manual control of valve when automation isn't possible or preferred
Overview
Installed between an actuator and valve, the Dynatorque™ SD declutchable manual override is compatible with both spring-return and double-acting actuators. It ensures reliable valve operation during maintenance, emergencies, and system failures. The durable design and simple installation suit a range of industrial settings, including oil and gas, water treatment, and manufacturing. A locking device for these overrides is also available to prevent unintended engagement or disengagement.
Side (left) and bottom (right) views of a Dynatorque SD declutchable manual override.
Applications
- Emergency operation of automated valves during loss of power, instrument air, or control signal
- Commissioning and functional testing of valves where manual positioning is required before the actuator is placed in service
- Maintenance and troubleshooting by isolating a process or cycling a valve while the actuator is being serviced or has been removed
- Remote or difficult-to-access installations where a reliable and local manual backup is required
- Critical shutoff or isolation duties (e.g., emergency shutdown valves and block valves) where manual intervention may be required as a contingency
- Processes with intermittent automation requirements
Benefits
- Enhances operational safety and reduces downtime by providing a reliable manual backup
- Enables controlled manual positioning with a self-locking worm gear that reduces the risk of unintended valve movement from process forces
- Supports safer and faster maintenance and commissioning by allowing manual stroking and positioning without removing the actuator or valve package
- Reduces wear-related intervention; typically lubricated for life with minimal periodic maintenance required under normal service
Features
- Standard ISO 5211 mounting dimensions on top and bottom flanges or custom machined for mounting to actuator and valve
- Switchable worm gear that enables manual or automatic operation
- Compatibility with both double-acting and spring-return actuators
- Transparent to valve operation when disengaged, enabling actuator to cycle without added loading
- Nine frame and spur combinations that provide output torque from 3,000 to 315,000 lbf.in [340 to 35,590 N.m]
- One-handed declutch mechanism
- Suitable for all handwheel applications with chainwheel adapters
- Compatibility with third-party sensor switches for improved monitoring and automation
Tech Specs
| Model | Unit Weight, lbm | Double-Acting Actuators: Max. Valve Torque, lbf.in | Spring-Return Actuators: Spring-End Torque, lbf.in | Override Max. Torque Rating, lbf.in | Mechanical Advantage | Standard Handwheel Size, in | Rim Pull, lbf | Standard Output Bore, in | Standard Keyway Size, in | Standard Bottom Mounting Pattern, (Quantity) and Tap Size, in | Standard Mounting Pattern (Bolt Circle Diameter), in | Standard Top Mounting Pattern, (Quantity) and Hole Size, in |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| DT3SD | 20 | 2,400 | 1,100 | 3,000 | 8.10 | 10 | 74 | 1.250 | 0.250 × 0.188 | (4) 5/16?–?18 |
2.756 (ISO F07) | (4) 0.344 |
| DT7SD | 28 | 5,600 | 2,600 | 7,000 | 12.96 | 14 | 77 | 1.750 | 0.500 × 0.375 | (4) 3/8–16 |
4.016 (ISO F10) | (4) 0.406 |
| DT12SD | 45 | 9,600 | 4,550 | 12,000 | 13.68 | 24 | 73 | 2.000 | 0.375 × 0.375 | (4) 1/2–13 |
4.921 (ISO F12) | (4) 0.562 |
| DT21SD | 62 | 16,800 | 7,775 | 21,000 | 13.20 | 30 | 106 | 2.500 | 0.500 × 0.500 | (4) 5/8–11 |
5.512 (ISO F14) | (4) 0.688 |
| DT36SD | 130 | 28,800 | 13,330 | 36,000 | 13.25 | 36 | 151 | 3.250 | 0.750 × 0.750 | (4) 3/4–10 |
6.496 (ISO F16) | (4) 0.812 |
| DT40SD | 130 | 32,000 | 14,815 | 40,000 | 19.84 | 36 | 112 | 3.250 | 0.750 × 0.750 | (4) 3/4–10 |
6.496 (ISO F16) | (4) 0.812 |
| DT50SD | 150 | 40,000 | 18,520 | 50,000 | 34.45 | 36 | 81 | 3.250 | 0.750 × 0.750 | (4) 3/4–10 |
6.496 (ISO F16) | (4) 0.812 |
| DT54SD | 163 | 50,400 | 23,330 | 63,000 | 51.68 | 30 | 81 | 3.250 | 0.750 × 0.750 | (4) 3/4–10 |
6.496 (ISO F16) | (4) 0.812 |
| DT90SD | 268 | 72,000 | 33,325 | 90,000 | 49.92 | 36 | 100 | 4.000 | 1.000 × 1.000 | (8) 5/8–11 |
10.000 (ISO F25) | (8) 0.688 |
| DT140SD | 271 | 112,000 | 51,850 | 140,000 | 78.00 | 36 | 100 | 4.000 | 1.000 × 1.000 | (8) 5/8–11 |
10.000 (ISO F25) | (8) 0.688 |
| DT315SD | 906 | 210,000 | 116,667 | 315,000 | 190.00 | 36 | 72 | 6.250 | 1.500 × 1.000 | (8) 3/4–10 |
11.732 (ISO F30) | (8) 0.810 |
Notes
- Handwheel rim efforts shown are calculated at unit maximum torque rating.
- DT50SD and DT90SD have a 4:1 spur assist; DT54SD and DT140SD have a 6:1 spur assist.
- Handwheels listed are recommended sizes to produce full rated torque with rim effort listed.
- Standard mounting patterns on all units are per ISO 5211 (UNC) specifications.
