Rotork Gears has developed the innovative DSIR Dual Speed Input Reducer for speeding up the manual operation of valves and valve gearboxes by reducing the total number of input turns required.
To achieve this, the DSIR has two gearing ratios. Switching between the ratios is simply a matter of pushing or pulling on the input shaft. The high 4.25:1 ratio gearing is used for the portion of the valve stroke where the torque requirement is high, which is usually at the beginning and the end of the stroke. In mid-travel the valve torque generally drops considerable and therefore the low 1:1 ratio gearing can be used to reduce the number of input turns required. This can provide a 70% reduction in the number of turns required and the operating time.
Manufactured from cast iron with carbon and alloy steel shafts and gearing, the rugged DSIR is designed for arduous operation in an ambient temperature range of -40?C to +120?C. The standard enclosure specification is watertight to IP67, with IP68 optionally available. Other options include output machining for mounting directly to a valve, flexible drive extensions and a padlockable facility. It is also possible to lock the gearbox drive in either of the two gearing ratios.