Denso system gives easier coupling gasket replacement
Methods
Denso system gives easier coupling gasket replacement
Keywords Coatings,Denso, Pipelines, Powerplants
The hydro-electric powered aluminium smelter of Alcan Smelting and Power UK at Kinlocheven in Scotland has been in operation for 90 years. And so have the 12km of pipelines that bring the water down the mountain side to drive the turbines.
The six 1m diameter pipelines, each 2km in length (Plate 10), were originally protected with a bitumen coating. This was deteriorating to such an extent that it was recently removed and a new liquid coating applied.
The pipes are joined by a type of spigot and socket secured by a separate bolted coupling with a sealing gasket. From time to time one of the 2,500 gaskets will fail and has to be replaced. The Alcan engineers required a protective system for the coupling that could be easily removed and reinstated after repairs had been carried out.
The system devised consisted of a circumferential wrap of Winn & Coales Dense Petrolatum Tape on the pipes either side of the coupling. This ensured protection of the pipes adjacent to the coupling. The coupling itself was given a liberal covering of Dense Protal Lubecoat, a non-hardening wax based liquid coating.
When a gasket fails, the tape is removed, the bolts loosened and the coupling slipped back along the pipes. The failed gasket is replaced and the coupling bolted tight. The tape and Protal Lubecoat are then replaced with new material. This operation can be quickly carried out by the maintenance crew without the need for special equipment.
Plate 10 The six 1m pipelines bringing hydro-electric power to Alcan's Kinlocheven smelter. The couplings are protected with a Denso system
Winn & Coales adds that the system ensures excellent protection to the pipe/coupling area and does not jeopardise the coating system on the body of the pipe.
Details from: Winn &Coales (Denso) Ltd. Tel: +44 (0)181 670 7511; Fax: +44 (0) 181 761 2456.
