Pneumatic Ledeen Actuators
Quarter-turn operation
Reliable performance with compressed air, natural gas, or nitrogen.
Dynatorque SRD non-declutchable manual override
Enables manual control of valve when automation isn't possible or preferred
Overview
Installed between an actuator and valve, the Dynatorque? SRD non-declutchable manual override is compatible with spring-return 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 SRD non-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 selflocking 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
- Transparent to valve operation when disengaged, enabling actuator to cycle without added loading
- Alternative to the Dynatorque™ SD declutchable manual override for spring-return applications
- Eleven frame and spur combinations that provide output torque ranging from 3,000 to 260,000 lbf.in [340 to 29,376 N.m]
- Designed to fail close or fail open based on the actuator’s fail position
- Worm wheel pocket that enables free driver movement when the actuator has air or power supply
- 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 | 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| DT3SRD | 19 | 1,111 | 3,000 | 8.10 | 10 | 74 | 1.250 | 0.250 × 0.188 | (4) 5/16–18 |
2.756 (ISO F07) | (4) 0.344 |
| DT7SRD | 27 | 2,593 | 7,000 | 12.96 | 14 | 77 | 1.750 | 0.500 × 0.375 | (4) 3/8–16 |
4.016 (ISO F10) | (4) 0.406 |
| DT12SRD | 45 | 4,444 | 12,000 | 13.68 | 24 | 73 | 2.000 | 0.375 × 0.375 | (4) 1/2–13 |
4.921 (ISO F12) | (4) 0.562 |
| DT21SRD | 62 | 7,778 | 21,000 | 22.50 | 30 | 62 | 2.500 | 0.500 × 0.500 | (4) 5/8–11 |
5.512 (ISO F14) | (4) 0.688 |
| DT36SRD | 126 | 13,333 | 36,000 | 19.00 | 36 | 105 | 3.250 | 0.750 × 0.750 | (4) 3/4–10 |
6.496 (ISO F16) | (4) 0.812 |
| DT40SRD | 126 | 14,815 | 40,000 | 27.60 | 36 | 81 | 3.250 | 0.750 × 0.750 | (4) 3/4–10 |
6.496 (ISO F16) | (4) 0.812 |
| DT50SRD | 154 | 18,519 | 50,000 | 60.80 | 36 | 46 | 3.250 | 0.750 × 0.750 | (4) 3/4–10 |
6.496 (ISO F16) | (4) 0.812 |
| DT54SRD | 151 | 23,330 | 63,000 | 91.20 | 20 | 69 | 3.250 | 0.750 × 0.750 | (4) 3/4–10 |
6.496 (ISO F16) | (4) 0.812 |
| DT90SRD | 258 | 33,333 | 90,000 | 49.92 | 36 | 100 | 4.000 | 1.000 × 1.000 | (8) 5/8–11 |
10.000 (ISO F25) | (8) 0.688 |
| DT140SRD | 261 | 51,852 | 140,000 | 78.00 | 36 | 100 | 4.000 | 1.000 × 1.000 | (8) 5/8–11 |
10.000 (ISO F25) | (8) 0.688 |
| DT200SRD | 724 | 74,074 | 200,000 | 150.00 | 36 | 74 | 6.250 | 1.500 × 1.000 | (8) 1 1/8–7 |
14.016 (ISO F35) | (8) 1.188 |
| DT260SRD | 764 | 96,296 | 260,000 | 264.00 | 30 | 66 | 6.25 | 1.500 × 1.000 | (8) 1 1/8–7 |
14.016 (ISO F35) | (8) 1.188 |
Table footnotes
Handwheel rim efforts shown are calculated at unit maximum torque rating.
DT50SRD and DT90SRD have a 4:1 spur assist; DT54SRD, DT200SRD, and DT260SRD 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.
