GLS & GLM Valve Interlocks
Handwheel-operated gate, globe, and gear valves — mechanical interlocking with simple key sequences.
Valve Interlocks & Portable Actuators — Sofis
Mechanical valve interlocks and portable actuators from Sofis. GLS, GLM, QLR, QLT interlock variants and the EasiDrive portable actuator — eliminating human error in valve operation.
Netherlands 30+ years interlock heritageSmith Flow ControlNetherlocksOverview
Valve Interlocks & Portable Actuators — Sofis
Sofis (incorporating Smith Flow Control, Netherlocks Safety Systems, and Ellis) is the global leader in mechanical valve interlocks. JST supplies the full Sofis range in Thailand — including handwheel interlocks (GLS, GLM) for gate, globe, and gear-operated valves, lever interlocks (QLR, QLT) for ball and butterfly valves, and the EasiDrive portable actuator.
Mechanical interlocking enforces correct valve operation sequences — eliminating human error, protecting operators, and reducing the risk of incidents during isolation, depressurisation, and product changeover. Some JST and Sofis partner-company staff have worked with valve interlocks for over 30 years.
JST's track record across Chevron Offshore, Tapline, HMC Polymer, PTT Asahi, and South Pailin includes interlock supply, on-site installation, operator training, and ongoing maintenance support.
Interlock Range
Interlock Variants & Portable Actuators
A complete mechanical interlock portfolio plus the EasiDrive portable actuator.
QLR & QLT Valve Interlocks
Lever-operated ball and butterfly valves — interlocked sequences for safe isolation and changeover.
EasiDrive Portable Actuator
Portable powered actuator for heavy or remote valves — reduces manual handling and operator fatigue.
Custom Interlock Schemes
Engineered sequences for complex isolation, depressurisation, and changeover scenarios.
Featured Projects
Field-Proven Across Southeast Asia
Sofis
Chevron Offshore, Tapline & HMC Polymer
Valve interlock installation across Chevron Offshore, Tapline, and HMC Polymer — full scope from key-scheme design through installation, training, and maintenance.
Sofis
PTT Asahi — EasiDrive
EasiDrive portable actuator supplied to PTT Asahi with operator training and ongoing maintenance support.
Related Services
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