The introduction of the IS21 gearbox adds higher thrust ratings to Rotork’s established range of multi-turn, thrust taking spur gearboxes. Retaining most of the parts from the IS20, the IS21 incorporates a new F60 cast ductile iron thrust base, thrust bearings, spigot ring and output sleeve. The resulting thrust rating rises to 4350 kN for manual operation and 2900 kN for motorised operation, an increase of 30% over the previous maximum. Corresponding maximum output torques rise to 46100 Nm and 43386 Nm respectively.

Designed for the operation of gate, globe and sluice valves and penstocks, all IS gearboxes are designed with customer stocking in mind, featuring a removable output sleeve for separate spindle machining. The standard IP67 watertight and temporarily submersible enclosure can be optionally increased to IP68, whilst the standard operating temperature range of -40ºC to +120ºC can also be expanded to suit specific high or low temperature demands.

The totally enclosed gearing is grease filled for life and available in a wide range of ratios. The option of combined spur and bevel gear combinations adds even more operational flexibility. The addition of the IS21 to the existing range enables the gearboxes to be used for the manual or motorised operation of the largest valves to be seen in markets including water and waste treatment, power generation, petro-chemicals and general industry.