This appraisal is for a range of Derwent mechanical couplings in sizes DN 100 to DN 300 complying with AS/NZS 4998:2009 Bolted unrestrained mechanical coupling for waterworks purposes. This Issue 3 is to include DN 300 size couplings to the range. Issue 2 was to include DN 200, DN 225 and DN 250 sizes.
Derwent unrestrained mechanical couplings are designed to suit a wide range of pipe outside diameters and are intended for jointing spigot ends of pipes, other than PE, in water and sewerage applications, either in above or below ground situations.
The couplings are supplied with Grade 316 stainless steel barrels and polymeric coated ductile iron end rings. The fastener options are either Grade 316 coated with a Molybond dry film coating or galvanized mild steel. The seals are NBR (Nitrile).