MS Series

Spring-Return Hydraulic Actuator

Compact. Simple. Versatile.
Delivering thrust up to 72,000 lbs and SIL-3 Capable. Our Spring-Return Hydraulic Valve Actuator is designed to suit a wide range of valve automation applications; from commodity to severe-service extremes.

electro hydraulic actuator linear valve automation

Taking Spring-Return Actuation to the Next Level:
Hydraulic Version Now Available


  • Bore Size: 1 1/2″ – 14″
  • Rod Size: 1″ – 7″
  • Configuration: Single-Stage
  • Stroke Range: Up to 24″
  • Pressure Rating: 3000 psi


  • Preloads up to 72,000 lbs
  • SIL-3 Capable
  • GT3 Triple Seal Gland for
    Severe Service Applications
  • Fail-Open or Fail-Close
SIL3 Logo
Download Our MS Brochure

Cylinder cutout showing springs of Hydraulic Spring-Return Valve Actuator - MS Series
  • Custom dimensional sizes and thrusts available
  • Springs are pre-compressed and sealed in a factory-installed canister
  • No extended tie-rods required
  • Standard offering – no custom design required
  • Proven seal technology

Safety comes first, stays first. Backed by Cowan Dynamics’ warranty and service/support guarantee.

Complete the form to get a quote within 24hrs.

Dual Speed Manifold of Hydraulic Spring-Return Valve Actuator - MS Series

Dual Speed Manifold

Dual-Speed Cam-Operated hydraulic manifold reduces speed at end of stroke to help prevent water hammer.

High and Low Temperature Ranges for Hydraulic Spring-Return Valve Actuator - MS Series

Control and Monitoring Solutions

GT3 Gland for Harsh Environments

GT3 Gland
Triple-seal gland with dual wipers. Rugged metallic scrapper and urethane double-acting wiper deflect contamination away from the rod seal for long service life.


Low Temp

Cast Iron construction for applications where yellow metals are not allowed

Mounting Kits: ISO, MSS & Customized Patterns Available

Mounting Kit
Cowan valve mounting kits can be designed for any linear valve. Mounting kits available in steel and stainless steel construction.

Anti-Rotation Torque Arm:

Maintains constant alignment between valve stem and cylinder piston-rod. Compatible with rotary type switch boxes and beacons.

Field-Adjustable Travel Stops:
To limit stroke for position-seated or limited-travel applications. Ensures valve reaches positive sealing every time without damage to valve internals.

HPU & Gas/Oil Systems

HPU & Oil/Gas System
HPU and Gas/Oil Systems available. Standard and custom units engineered to customer specifications and applications.

The MS Series is yours in just a few clicks.

Complete the form to receive a quote within 24 hrs.