Valve gearboxes manufactured by Rotork Gears have been supplied for the operation of giant butterfly valves as part of the 17 billion Renminbi (RMB) scheme to increase and improve the supply of fresh water to the city of Shanghai.
The Qingcaosha raw water project will provide a daily supply of more than seven million cubic metres of clean water through a network of huge pipelines, the main four with a diameter of 5.5 metres. Rotork’s heavy duty IW17 worm gearboxes were ordered to operate butterfly valves manufactured by CVVT (China Valve Technology Ltd) on these pipelines.
With a gear ratio of 14142:1 and an output torque of 850,000 Nm, the gearboxes enable manual valve operation or operation with a portable pneumatic tool.
Rotork IW quarter-turn worm gearboxes are designed for use with low or no maintenance in rugged service duties. Available for clockwise or anti-clockwise valve operation, they feature a minimum safety factor of twice the maximum output torque. Tightly controlled manufacturing tolerances provide negligible backlash between the worm and quadrant to give accurate movement and reduced vibration during travel.
Grease filled for life, the gearboxes are ‘O’ ring sealed with an IP67 or IP68 watertight enclosure for service in all environments at ambient temperatures between -20ºC and +80ºC. Options include high or low temperature service, limit switches, flexible drive extensions, padlock kits and an AWWA specification.