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Derwent Couplings® were recently added back into the Derwent range with a new state of the art robotics manufacturing facility being established in North East Victoria.

The Stainless Steel Couplings(Kawandah®TM ) were developed for the Australian and export markets  by the Evans Group of companies, in Wangaratta Victoria. The iconic logo of the cockatoo (Current trademark) is the logo we are still proud to use today to represent the range.

Derwent Industries Variable Couplings are Australian manufactured. The couplings have been designed to alleviate the issues encountered when connecting pipes of different outside diameters and/or pipe materials. The coupling provides the installer with a precise simple way of connecting pipes that have OD variances of up to 24mm.

Derwent Industries manufacture and distribute under the Derwent brand the range of mechanical Couplings.

Technical Data:

Temperature Range:               -10°C to 60°C


Max. Operating Pressure:     1600 kPa 

Deflection:                               DN100 - DN 150
                                                  (6° each end on range of coupling)

                                                  DN200 - DN 300
                                                  (3° each end on range of coupling)


Quality Assurance:                 ISO9001:2015


Certificate Number:               QEC2004

Please refer to your local water authority for schedule of approved products.


• 316 Stainless Steel Sleeve for superior corrosion protection

• 316 SS Bolts and Nuts coated with molybond to prevent galling

• Flanges are Ductile Iron, Fusion Coated• Nitrile Gasket

• Sleeves are fully passivated, ensuring superior quality

• Ease of installation via tension wrench

• All bolts are supplied with plastic thread protectors

• Barrel is convex (not straight) allowing for angular deflection to be achieved.


The Derwent Industries Variable Couplings are the perfect solution for joining two sections of pipe together. The coupling allows for an OD variance between pipes requiring joining, allowing for a simple repair to damaged sections of pipe or for new joins. Regulations at water authorities may differ as to allowable usage.

Variable Couplings are not suited to all type of pipe, such as Polyethylene unless a form of restraint is included in the coupling.

Please refer to installation instruction for all installations.


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