We have developed what is believed to be the worlds first purpose made plasma cutting system for use by divers. Working closely with the UK Ministery of Defence (MOD), with input from the Royal and U.S. Navy`s and others, the potential hazards were identified, and solutioins found eliminate risk The equipment has so far been proven in trials down to 30m (100’) depth, cutting metals to 40mm (1.5”) thick.

Plasma Arc metal cutting equipment typically uses voltages of 300 v or more, against a background of Codes of Practice in diving work favouring no more than 30 volts. Whilst plasma cutting equipment has occasionally been used underwater, there have been risks present requiring very careful application of safe working practices. This equipment is designed to control electrical leakage paths at source and prevent them reaching the diver. The methods have application to any exposed voltage process where currently shocks are routinely experienced.

Click here to view a paper on developement of electrical safety underwater.

The advantages over other metal cutting methods currently in use include high cutting speed, low running cost, and excellent cut quality. Apart from ensuring electrical safety, safety issues concerning oxygen and blow-back are eliminated and the environmental impact reduced. In spite of higher initial; equipment cost the combination of high cutting speed and low running cost can show a pay-back inside one week! This is before considering the savings that good cut quality might also bring.

Click on the picture to see video of a piece of 25mm mild steel being cut in a tank trial. The length of cut is 250mm.

Application

Wheter Offshore, in MArine Engineering or Civil Works, the ability to cut metal underwater can be requirment. Established methods are often slow and can have a high consumable cost. The logistics of supplying gas to those processes using oxygen can be a further problem.

Air Plasma cutting overcomes many of these problems by offering high cutting speeds at relatively low running costs. It offers further advantages in the quality of the cut edge, and the precision and degree of control of the cut, eliminating secondary operations such as grinding, which may be required with some established methods.

The disadvantages is the higher initial cost, although this is swiftly recovered in use, and the need for training, as with any new process. With proper training in correct operation materials in excess of 40mm can be cut. The equipment can also be used on the surface where the full 65mm capactiy of the standard P30 is available.