Power Jet Systems (PJS) has demonstrated its concrete scabbling techniques to a variety of customers at Nuclear Engineering Services' (NES) open days. The company supplies ultra-high-pressure water-jet cutting solutions to a number of industrial clients, but believes the very high pressure (VHP) scabbling techniques developed will have a variety of applications within the nuclear and general industrial markets.Supported by Kuka robotics, the scabbling process can supply a fully enclosed concrete removal method suitable for pond wall and silo scabbling. Utilising a six-jet scabbling head, rotating at approximately 2,000revs/min, the equipment provides variable removal rates, with NES typically working at 6mm deep scabbling covering approximately 8m2 per hour. Driven manually or by an automated programme, the Kuka robot provides an ideal system for the VHP scabbling equipment to be mounted to. NES is developing a number of platforms to attach the PJS scabbling system to, including fixed robotic arms and crawler robots.
Supporting the scabbling and robotic systems is a 37kW vacuum pump extracting the wastes from the concrete surface at the point of scabbling. The 2,750m3 per hour capacity extraction unit is capable of separating solid from wet wastes. The vacuum system can also be run through a filtration system allowing the air and water to be free released. Through the utilisation of VHP, the volumes of water required for this process are reduced from that of high-pressure water jetting. The scabbling system uses approximately 15litres per minute, at a pressure of 30,000lb/in2.
Supplying the VHP water to this system is a 100hp pump unit powered by either diesel or electric, certified for use in hazardous environments. The Triplex piston pump unit is capable of delivering up to 30litres per minute at a pressure of 45,000lb/in2. PJS has also recently carried out underwater scabbling techniques on concrete. This technique will allow pond walls to be scabbled with the water remaining. This holds advantages over an empty pond as the water can be used as a natural barrier to the radiation.
