Smith Flow Control and Netherlocks have merged. We are now Sofis.

Smith valve interlocks

The industry standard for premium valve interlocks. Originators of coded card linear key.

Global standard for premium interlocks

Smith Flow Control introduced the modern valve interlock in 1985. The brand became the global standard for premium valve interlocks. Smith valve and equipment interlocks provide highly reliable sequencing for operation of your valves and adjacent equipment.

Safe and efficient valve operation

Valve interlocks guarantee safety and right-first-time manual valve operation through a key transfer principle. Valve interlocks are mechanical devices which are permanently mounted on your equipment. They avoid operator errors by enforcing adherence to procedures. By eliminating the chances of human error, they avoid costs and safety risks.

Smith valve interlock
Valve interlocks on gearbox valves

Optimize your operating performance

  • Guaranteed right-first-time operation
  • Higher equipment efficiency and asset availability
  • Reliable process status feedback through colour-coded key positions
  • Improved HS&E performance

Premium design

  • Integral lock assembly
  • AISI 316 Stainless steel
  • Standard coated body

Easy installation

  • Bespoke mounting kit for perfect fit
  • Sequence-free commissioning with one-time commissioning keys

Optimal reliability

  • Anti-tamper assembly
  • Linear key improves reliability and operability
  • Uniquely-coded keys for each lock

Universal applicability

  • Fits any quarter- or multi-turn valve
  • Fits large valves and gearboxes with high rotation counter
  • Integrates adjacent equipment into operational sequencing
smith valve interlocks on gearbox valves
Smith Valve interlock on multi rotation valve

Easy installation

  • Bespoke mounting kit for perfect fit
  • Sequence-free commissioning with one-time commissioning keys

A Smith lock for every piece of equipment

Engineering support

Valve interlocking application is probably not part of your daily routine. We can lend you our extensive application expertise and over 30 years of field experience and project management skills. Our global team of engineers will help you with valve operating sequence design or customized interlocking solutions.

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