Valve interlocks enforce and guarantee a pre-defined sequence of operation, and therefore eliminate human error. They are used as an industry standard by renowned companies to create a safer working environment.

 They are used in many applications where safe and ‘first time right’ valve operation is required, such as pressure relief valves (PSV), pig launching and receiving, inert gas systems, pump start up, flare lines, boiler blow-down, ‘2 out of 3‘ and decoking.

Dedicated to getting people home safe and increasing overall plant safety and efficiency, Sofis manufactures valve operation systems such as mechanical valve interlocks, portable actuators and valve position indicators. It is the world’s largest interlock manufacturer, providing bespoke design solutions that protect people and property throughout the world.

 Teksal Safety is the Australian distributor for Sofis (formerly Smith Flow Control) valve interlocking and process safety systems, and supports Sofis’ complete range, including supply, installation, commissioning and training services.


Plant operations, when performed incorrectly, can have catastrophic consequences in safety-critical industries. To mitigate the effects of human error, valve interlocking systems are widely employed in risk management strategies, forming an important component of process safety. A valve interlocking system ensures a predetermined sequence of valve operations can be achieved by using a “trapped key” principle.

Available in quarter-turn and multi-turn versions, valve interlocks are designed to suit all types of valves and can be fitted to the valve without needing hot work or modification to the host valve. When used with other Sofis interlocks, operators are compelled to follow the correct sequence of operation of all valves and equipment within the interlock sequence.

Given the diverse applications interlocks can be used for, as part of HAZOP or design reviews, we can help define and review the sequence and create the interlock specifications.


VPI is a high-performance switch box for manual multiturn valves. It detects when valves have reached their open or closed position and sends a signal to your DCS. This valuable information about manual assets enriches your control system’s capabilities. It helps to further optimise your process performance, and prevents safety issues or product contamination caused by incorrect valve line-ups.


Flexible Remote Valve Operators – FlexiDrive

FlexiDrive is a versatile product consisting of two stations, joined by a unique, patented, linear drive cable. This equipment enables valves and other wheel-operated devices in remote, hard-to-reach or hazardous locations to be operated easily from a conveniently located handwheel.

Developed to operate valves in inaccessible locations, FlexiDrive can be applied to any conventional wheel-operated valve/device, in oil, gas and chemical processing plants, or any other industrial application. It is suitable for underwater use and will function reliably in all climatic conditions.

Portable Valve Actuators – EasiDrive

EasiDrive is an efficient, cost-effective alternative to a dedicated valve actuator. Wherever you have manually operated valves that have high-operating torques, hundreds of handwheel turns to open/close or are difficult to operate, EasiDrive is your ideal solution.

EasiDrive is fully portable and banks of valves can be managed with a single tool. Pneumatic, electric and hydraulic ‘drive guns’ are available.


The Power Wrench portable actuator reduces valve operating time by up to 80% and improves efficiency when operating manual valves. Install the drive plate with u-bolts, connect the Power Wrench portable actuator to an air supply and you are ready to go!

With the Power Wrench portable actuator you work more efficient during plant stops and maintenance. Put the tool to work in your plant within minutes and limit the time spent on operating manual valves. The Power Wrench is Ex certified and ready for use in Zone 1 classified areas.

Operation of the Power Wrench portable actuator is perfectly safe. You are in complete control over the applied force and various safety measures protect you during operation. The throttle allows for a controlled build-up of torque and speed and the safety lever and throttle valve enforce ‘2-hands operation’.


For more information about any of these products, call our office, email or visit our shop.