Rotary Distributors: Features
ELECTRIC DRIVE OPTIONS
All electric drive options use an electric motor connected into a speed reducer gearbox which is then connected to a disengagement clutch. The electric drive system has 3 optional mounting positions :
- TOP DRIVEN SPUR GEAR (typically on filter bed diameters <10m)
- The electric drive system is mounted onto the top of the central column and from here drives a spur gear ring to effect distributor rotation. The spur gear ring is manufactured in accordance with AGMA (American Gear Manufacturers association) and the teeth have a hardness of 250-300 Brinell.
- DRUM DRIVEN SPUR GEAR (typically on filter bed diameters 10m-25m)
- The electric drive system is mounted onto the central column inside the rotating drum and from here drives a spur gear ring to effect distributor rotation. The spur gear ring is manufactured in accordance with AGMA (American Gear Manufacturers association) and the teeth have a hardness of 250-300 Brinell.
- ARM DRIVEN SPUR GEAR (typically on filter bed diameters 25m-35m)
- The electric drive system is mounted inside the central well and from here drives a spur gear ring to effect distributor rotation. The spur ring gear is attached to the underside of the distributor arms.
The electric motor is rated to suit customer’s application. Options are :
- Power sizes from 0.12kW upto 4.0kW
- 2, 4, 6 or 8 pole motors
- IP55, IP56 or IP67 degrees of motor protection according to the requirements of enclosure protection standard IEC 60529
- Thermostat (Klixon) thermal overload protection or thermistor thermal overload protection.
- Anti-condensation heater 220 or 110 volts single phase
- Natural ventilation for speed range 10 Hz to 50 Hz
- Forced ventilation for speed for 3Hz to 50 Hz
The reducer gearbox is specified to suit customer’s application. The gearbox is selected according to required output speed and required output torque.
Aspinalls offer a range of disengagement clutches to suit customer’s application. The options include :
- 3 model sizes of clutch
- Protection in accordance with the requirements of either IP54 or IP55
The purpose of the clutch is to automatically disengage the drive motor from the spur gear in the event of power failure or motor loss of rotation to allow a backup hydraulic drive system to continue distributor rotation.
The central column of an Aspinall rotary distributor is fitted with upper and lower heavy duty bearings capable of accommodating combined high axial and radial loads. The bearings have a basic rating life of 11,000,000 revolutions and are pre-packed with an extreme pressure additive lubrication grease. This grease is topped up during operation by an automatic lubrication system.
OPEN TROUGH ARMS
The standard Aspinall arm design is the open trough fitted with “V” shape or “U” shape notched weir plate. The pattern of the notches is designed to distribute an even curtain of effluent to the filter media surface.
Upon request closed tube design of arms are available.
On jet reaction and paddlewheel applications the speed of rotation varies relative to the incoming flowrate. Reverse thrusters are used to slow down the relative speed of rotation to suit the customer’s specific operating conditions.
MATERIALS OF CONSTRUCTION
The rotating drum and the distribution arms are manufactured from high quality stainless steel conforming to the requirements of BS 1501 part 3.
The central support column is manufactured from high quality carbon steel with either a subsequent protective hot dip galvanised coating in accordance with BS729 or a subsequent epoxy paint coating system.
Each standard design of Aspinall rotary distributor requires a given minimum head for satisfactory distributor performance. The client’s distribution chamber should be given adequate elevation to provide the minimum head requirements.
For non standard distributor designs to accommodate low available heads consult Aspinalls for further advice.