Safe not sorry For tamperproof operation, the engineer requested a lockable option. Choices included a button lock or a key lock. Make it BLUE By designing a custom zero-leak rotary shear valve solution using the Make it BLUE process, Webtec helped the design engineer overcome all four key challenges. The same process benefitted the service manager, who Fig. 3 – Rotary shear valve principle of operation Fig. 4 – Leakproof arrangement with rotary shear directional valve Fig. 5 – Valve locking options The final solution used a button-lock mechanism with a unique locking plunger. After the handle is moved, the plunger automatically locks it in position. The operator must Fig. 6 – Winch lowering during power failure had the unique requirement of placing multiple shear valves in series. The engineer specified a 350 bar (5000 psi) valve capable of pressurising the tank line and feeding that flow into the pressure line of the next valve. Two approaches were considered: pressurising the T port, which would require a stronger valve body; or adding a fifth port with a case drain from the top cap feeding separately to tank. Both were feasible, but the engineer chose the latter. www.hpmag.co.uk HYDRAULICS & PNEUMATICS February 2026 21 system also required specifying a bespoke valve that would minimise piping and reduce installation costs. The preferred solution was a custom 8-port valve with four ports duplicated on the bottom and side. This allows users to select which ports to employ in different configurations while plugging the unused ones. Under pressure High-pressure capability is a common request for shear valves, but this project needed a replacement valve—plus additional functionality—for controlling winches on ageing mobile drilling rigs. Like the design engineer, the service manager identified four key challenges: combining directional and pressure control, introducing flow regulation, enabling remote mechanical actuation, and resisting harsh weather conditions. Because the existing valve included built-in relief, the replacement also needed combined directional and pressure control. A spool valve was unsuitable due to leakage causing the winch load to drift downward. A zero-leak rotary shear valve eliminated this issue by providing reliable load holding and smooth operation. A secondary override function also allowed winch movement during power failure. The solution incorporated an integral pilot relief valve with a pressurised tank port and an additional vent/tank connection. The incoming pressure line was therefore protected by the relief valve, while the vented tank connection (fifth port) enhanced control. Interflow requirement The service manager also required finer flow regulation without installing a separate flow regulator. Achieving this with a directional valve called for an “interflow” design, which allows a small amount of flow during the transition between positions. This provides smoother, more controlled cylinder movement. Mechanical actuation The valve needed remote mechanical actuation via a unique linkage because of its inaccessible location inside the machine. Options included a detent mechanism, where the handle stays in place, or a spring-centred design. In this case, the handle was removed and replaced with a pin to interface with the mechanical actuator. Weatherproofing Because the mobile drilling rigs operate in diverse and often coastal environments, the final requirement was for a zero-leak rotary shear valve with a stainless-steel body for corrosion resistance. For further information please visit: www.webtec.com
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