Coupling proves worth in Malaysia

Malaysian pump house shows benefits of metal disc style shaft coupling used with composite shafting.

The TB Woods Form-Flex metal disc style shaft coupling has been used with composite shafting for many years.

If an application has a large distance between the driver and driven ends, the traditional design would be to incorporate a steel drive shaft between the two flexible coupling units.

However, using steel shafting in this way can have disadvantages.

Primarily, the weight of the connecting shaft could mean additional bearing mounts and inertia problems to the whole design especially when large span distances are required and again when using couplings suited to bore sizes of 25mm and above to a maximum of 400mm.

The key advantages to using composite shafting lie in its weight saving characteristics and its inherent nature to transmit high torques reliably with near zero torsional wind up.

A example of this capability was put to the test at a pumping house in Malaysia.

The original design incorporated four heavy cardan shafts to span a vertical distance of 13.89m.

During an upgrade of the motors within the plant, to cope with increasing demand, it became apparent that due to poor bearing mounts, large inertia and unbalanced cardan shafting, the plant could not safely operate more than about five or six of nine pumps at a time.

The engineers suggested a three-section lightweight composite Form-Flex coupling design to transmit the 820kW at 1500rev/min.

Reducing the weight of the system also enabled one of the additional bearing mounts to be omitted, further improving vibration dampening within the design.

Other applications where the Form-Flex couplings and composite shafting combinations have successfully been used include cooling tower axial fan drives and gearbox to dredge pumps on underwater dredging vehicles.

The products are available in the UK from Abssac.

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