Smith Flow Control has launched an enhanced version of its Flexi-Drive cable-driven remote valve operator. The new ‘Continuous Loop’ version has the same versatility as the original model but can transmit drive to valves through much shorter cable runs, even if a large number of handwheel turns is required. With the old system, the number of handwheel turns determined the length of the drive cable: the greater the number of turns, the longer the cable. The new ‘Continuous Loop’ system does away with this requirement by circulating the drive cable through a gear mechanism, eliminating the need for a long cable. Of course, some operators will actually require a long cable run. For this reason the new Flexi-Drive, like its predecessor, still has the capacity to transmit drive as far as 60m away, accommodating 540 degrees of bends in the cable run. The new system consists of three elements: an operator station (consisting of a geared handwheel and mounting facility), a valve station actuator, and a unique, patented helix drive cable. Due to the properties of the strong, flexible steel cable, turning the handwheel of the operator station simultaneously operates the valve actuator. The cable allows high valve operating torque to be transferred through walls, bulkheads, floors, tunnels and any other obstacles between the handwheel and the valve. Suitable for any size or type of valve, regardless of torque or turn requirements, the ‘Continuous Loop’ Flexi-Drive is available in a range of reduction ratios, including 4:1, 2:1 and 1:1, with no danger of delivering over-torque. With a service life of 20,000 valve cycles, the new Flexi-Drive is said to ensure uninterrupted operation for the life of any valve. It is completely sealed and permanently lubricated, never requiring maintenance. A further advantage is that the gearing system can be ‘piggy-backed’, allowing more than one valve to be operated from a single operator station. The ‘Continuous Loop’ Flexi-Drive is designed to withstand the most severe conditions, including high impact shock, sinusoidal vibration and open flame. It can be used down to 15m under water and in temperatures ranging from –54o to +200oC.
