The functional principle of pressure generation

Waterjet cutting - a technology on the rise

Treated water with an optional long-chained polymer content is pressurized from line pressure to 7 bar by means of a booster pump. The water flows into the high-pressure cylinder via a water filter. The principle of the pressure intensifier consists of a primary circuit which operates at 200 bar by means of an electrically driven hydraulic pump. The fluid is pumped alternatingly into the right-hand or left-hand side of the hydraulic cylinder by means of a four-way valve.

The piston rods installed in the hydraulic pistons of the secondary water circuit are also moved. Corresponding non-return valves for water inlet and outlet control the filling and discharge of pressurized water in the high-pressure cylinder. A water pressure of 4.136 bar is generated via the surface ratio of 20:1 of the hydraulic piston to the piston rod. A pressure accumulator (surge damper) is installed to minimize pressure peaks during changeover from one side of the cylinder to the other. The high pressure pump is connected to the cutting-head via high tensile-strength stainless steel tubes. A sapphire or diamond nozzle converts the pressure to a high-velocity jet of water (approx. 800 to 1000 m/s).

An abrasive is added in order to further enhance the efficiency of the jet of water. After addition of the abrasive, water, air and abrasive are mixed in the mixing chamber, collimated in the focusing nozzle and accelerated. The result of this technique is a high-energy jet which is capable of micro-eroding, i.e., drilling and cutting, materials of great thicknesses and of the most diverse consistencies, such as metals, ceramics, rock and bulletproof glass.

Fig.: The intensifier principle: A electro-motor drives a hydraulic pump pressurizing the oil circuit of the intensifier, where the pressure is increased 20 times and fed into the system.