Bettis CBB 520-SR80 Pneumatic Actuator

Bettis CBB 520-SR80 Pneumatic Scotch-Yoke Actuator

The Bettis CBB 520-SR80 is a heavy-duty spring-return pneumatic scotch-yoke actuator designed for reliable fail-safe automation of quarter-turn valves. As part of the CBB-Series, this model delivers high break torque, robust mechanical performance, and long operational life, even under demanding service conditions.

The SR80 spring-return configuration provides fail-safe action—either fail-open or fail-close depending on installation orientation—ensuring dependable shutdown performance in critical process applications. The actuator features a strong ductile-iron housing, a high-efficiency scotch-yoke mechanism, and a precision-engineered spring module that delivers consistent, powerful return force across the full stroke.

Suitable for ball, butterfly, and plug valves, the CBB 520-SR80 is widely used in oil & gas, petrochemical, refining, power generation, and general industrial systems requiring high torque and dependable emergency shutdown capability.

Technical Specifications — Bettis Type CBB 520-SR80

Actuator Type

• Pneumatic quarter-turn actuator

• Scotch-yoke mechanism

• Spring-Return configuration (SR80 spring module)

• Model size: CBB 520

Performance

Spring-Return Characteristics (SR80)

• SR80 spring module provides strong and consistent fail-safe torque

• Delivers high break torque during fail-stroke (spring stroke)

• Suitable for valves requiring high unseating torque

Cylinder Volumes

• Inboard and outboard cylinder volumes sized for high-torque output specific to CBB520

• Balanced air chamber capacity for efficient power stroke

Operating Pressure

• Supports typical industrial instrument-air pressures

• Compatible with torque charts for accurate valve sizing

Pressure Ratings

• Maximum Operating Pressure (MOP): approx. 120 psig

• Maximum Allowable Working Pressure (MAWP): approx. 200 psig
  (Values follow the standard pressure ratings of the CBB-Series in this size range.)

Construction & Materials

• Heavy-duty ductile iron or carbon steel housing

• Spring pack enclosed in a robust SR80 module

• Hard-wearing scotch-yoke mechanism for high reliability

• Internal surfaces designed to reduce friction and extend service life

• External components built to withstand corrosive and industrial environments

Dimensions (Typical for CBB 520 SR)

(Values vary by selected configuration and accessories; based on the 520 model dimensional range)

• Overall length: approx. 20–24 in

• Height: approx. 10–12 in

• Drive housing width: approx. 4.5–5 in

• Pressure ports: typically 3/8" NPT

• Mounting bolt pattern: standardized Bettis CBB interface

• Output shaft: square/drive dimensions compatible with quarter-turn valves

Weight

• Approx. 25–35 kg depending on housing materials and SR80 module
  (Spring-return versions weigh more than double-acting models due to spring module.)

Operating Characteristics

• 90° rotary motion

• Fail-safe operation (fail-open or fail-close)

• High break-torque scotch-yoke profile

• Suitable for vertical or horizontal mounting

• Compatible with valve automation accessories:

  • Limit switches

  • Positioners

  • Solenoid valves

  • Manual overrides

Applications

• Emergency shutdown (ESD) valves

• Ball, plug, and butterfly valves

• Pipeline block valves

• Chemical and petrochemical process isolation

• Power plant valve automation

• Oil & gas upstream, midstream, and downstream operations