DT, SRD, and BG Locking Devices
For quarter-turn, multiturn, and bevel-gear operators
Avoid inadvertent handwheel rotation.
Dynatorque 90 quarter-turn worm gears
For valves and dampers requiring dependable and controlled 90° rotation
Overview
Engineered for reliable and precise operation
Dynatorque™ 90 quarter-turn worm gears are used to operate quarter-turn valves, dampers, and rotary devices across a wide range of industrial applications. Designed with a self-locking worm gear mechanism, they ensure controlled torque transmission and secure valve positioning, even under demanding operating conditions. Their ability to integrate with both manual and automated systems, together with a broad accessory portfolio, makes them the preferred choice for OEMs; engineering, procurement, and construction (EPC) companies; and end users, worldwide.
Built on a flexible manufacturing platform, the gears are offered with multiple mounting interface dimensions, while custom-machined versions can include bores and bolt holes for direct valve mounting. Gearbox housings are generally made of cast gray iron, with ductile iron and other material options available for specialized applications.
Exterior (left) and cutaway (right) views of a Dynatorque 90 quarter-turn worm gear.
Applications
Widely used where quarter-turn valve operation and reliability are critical, including
- ball, butterfly, and plug valves in process and pipeline systems
- dampers and rotary equipment in power and industrial plants
- oil and gas, chemical, and petrochemical facilities
- water and wastewater systems, including AWWA*-compliant installations
- marine, submerged, and extreme-temperature environments
* American Water Works Association
Benefits
- Controlled operation: Smooth worm gear engagement delivers precise torque control, enabling operators to position valves accurately throughout the 90° stroke
- Enhanced safety: Self-locking capability prevents back-driving, ensuring that valves remain securely in position even under load or system pressure
- Reduced operating effort: Optimized gear ratios and mechanical advantage help minimize manual effort, facilitating operation in high-torque applications
- Customizable solutions: A wide range of mounting interfaces, materials, and configurations enable tailoring the gears to specific valve requirements
- Lower life cycle cost: Durable construction and application-specific design contribute to long service life, reduced maintenance, and improved overall reliability
Features
- Available in 16 frame and spur gear combinations
- Gearbox housings available in cast gray iron or ductile iron
- Custom-machined bores and bolt patterns available for direct valve mounting
- Compliance with AWWA C-504 requirements on request
Tech Specs
Specifications
| Model | Unit Weight, lbm | Max. Output Torque, lbf.in | Gear Ratio | Turns for 90° | Std. Output Bore, in | Std. Key Size, in × in | Std. Mounting Pattern (Qty. and Size) |
Std. Mounting Pattern (Bolt Circle) |
Mech. Adv. | Handwheel Size, in | Approx. Rim Pull, lbf |
| DT1 | 5.4 | 1,500 | 30:1 | 7.5 | 0.501 | 0.125 | (4) 5/16-18 |
2.756 | 8.1 | 6 | 67 |
| DT3 | 7 | 4,500 | 30:1 | 7.5 | 1.000 | 0.250 | (4) 3/8-16 |
3.250 | 8.10 | 14 | 80 |
| DT7 | 15 | 10,000 | 48:1 | 12 | 1.750 | 0.375 | (4) 1/2-13 |
5.000 | 12.96 | 18 | 86 |
| DT8 | 19 | 8,000 | 30:1 | 7.5 | 1.750 | 0.375 | (4) 1/2-13 |
5.000 | 8.10 | 24 | 82 |
| DT12 | 26 | 16,000 | 57:1 | 14.25 | 2.000 | 0.375 | (4) 1/2-13 |
4.921 | 13.68 | 30 | 78 |
| DT21 | 34 | 26,000 | 60:1 | 15 | 2.500 | 0.500 | (4) 5/8-11 |
5.512 | 22.50 | 30 | 77 |
| DT36 | 78 | 36,000 | 53:1 | 13.25 | 3.250 | 0.750 | (4) 3/4-10 |
6.496 | 19.00 | 36 | 105 |
| DT40 | 78 | 40,000 | 79:1 | 19.75 | 3.250 | 0.750 | (4) 3/4-10 |
6.496 | 27.60 | 36 | 80 |
| DT50† | 105 | 50,000 | 212:1 | 53 | 3.250 | 0.750 | (4) 3/4-10 |
6.496 | 60.80 | 20 | 82 |
| DT54† | 108 | 63,000 | 318:1 | 79.5 | 3.250 | 0.750 | (4) 3/4-10 |
6.496 | 91.20 | 18 | 77 |
| DT60 | 111 | 60,000 | 60:1 | 15 | 3.250 | 0.750 | (4) 3/4-10 |
10.250 | 15.60 | 36 | 213 |
| DT90† | 145 | 90,000 | 240:1 | 60 | 3.250 | 0.750 | (4) 3/4-10 |
10.250 | 49.92 | 36 | 100 |
| DT140† | 148 | 140,000 | 360:1 | 90 | 3.250 | 0.750 | (8) 3/4-10 |
10.250 | 78.00 | 36 | 104 |
| DT200† | 278 | 200,000 | 450:1 | 112.5 | 4.750 | 1.25 × 1.0 | (8) 1 1/8-7 |
14.016 | 120 | 36 | 93 |
| DT220† | 402 | 220,000 | 600:1 | 150 | 6.250 | 1.5 × 1.0 | (8) 1 1/8-7 |
14.016 | 150 | 36 | 81 |
| DT300† | 460 | 300,000 | 1,200:1 | 300 | 6.250 | 1.5 × 1.0 | (8) 1 1/8-7 |
14.016 | 264 | 30 | 75 |
† Units with spur assist.
Notes
- Handwheels listed are recommended sizes to produce full rated torque with the rim effort listed.
- Bore, keyways, and mounting patterns listed are per SLB standards.
- Standard mounting patterns on the DT3 through DT54 are 4 tapped holes straddling the centerline at 45°. Standard mounting patterns on the DT60 through DT300 are 8 tapped holes straddling at 22.5°.
