Bevel gear actuators are typically used for multi-turn applications unlike the worm gear actuator the bevel gear actuator does not incorporate end stops.
Bevel gear actuators can be specified to operate on non-rising or rising spindle applications where it is the requirement of the bevel gear operator to accept the thrust of the valve.
The bevel gear actuator can be used in manual applications with a hand wheel, generally actuators for these applications are classed as commercial grade service and do not include hardened gears or additional bearings at the input shaft.
The stem nut for rising stem applications is normally manufactured of AB1 and screw cut to suit the valve stem thread form.
The bevel gear actuator provides a mechanical advantage therefore reducing the torque or effort required to operate a valve, available in various ratios ranging anywhere from 2 to 8:1 reductions, a range of spur gear attachments are also available for applications requiring high output torques and a reduced input.
For manual applications there is the option of a Hammer-Blow effect to assist in unseating sticky valves.
Selection of bevel gear actuators is similar to that of the worm gear actuator and is typically:
- Maximum torque the actuator will be required to produce
- Valve stem diameter, this is critical for rising spindle valves as the bevel gear actuator must be able to accept the maximum diameter of the valve stem
- Input torque limitations
- Mounting base configuration, bolt size etc
- Actuator grade or construction
- Environmental considerations
The bevel gear actuator is also available for operation when close-coupled to an electric or multi-turn pneumatic actuator, this combination can provide substantial cost savings when compared to direct mounting an electric actuator, and this also provides the benefit of extended operation times for municipal applications.
As with the worm gear actuator, the bevel gear actuator generally utilises hardened gearing as well as additional bearings to cope with added loads and extended operating cycles.
The bevel gear actuator can be specified with various options, stem tube protection covers, various size hand-wheels, local position indicator and overload protection devices.
Bevel gear actuators available from Acrodyne .