​Inductive sensors provide stroke feedback in pressure intensifier of water jet cutting machine

​Inductive sensors provide stroke feedback in pressure intensifier of water jet cutting machine


A US manufacturer of water jet cutting machines uses Contrinex High Pressure sensors (Extra Distance family) to regulate the action of opposed, reciprocating pistons in the pressure intensifier.


Water jet cutting is utilized in a wide variety of industries as a method of making precise and intricate cuts. High pressure water alone may be used, or abrasive material may be added to the water stream. Pressures of up to 90,000 psi (approx. 6200 bar) can trim vegetables, cut shapes from foam, and cut metal without leaving behind traces of material or lubricants. These high pressures are generated by the pressure intensifier: a system of opposed reciprocating hydraulic pistons driving small cylinders. These force the water through an orifice, accelerating the flow at high pressure. The reciprocal action of these opposing pistons is regulated by a directional control valve. Within this high pressure, hydraulic system, inductive sensors must deliver precise, instantaneous stroke feedback to the directional control valve.


Two Contrinex High Pressure sensors (series 500P) are mounted in specially machined ports in the hydraulic piston chamber at the two limit points of piston travel, where pressure on the water side is highest. When the end of travel is detected, a signal is sent to the machine controller which operates the directional control valve, propelling the assembly in the opposite direction and thus generating a pumping action. The cycle is constantly reversed and repeated (typically once per second).

The High Pressure sensor’s peak rating of 1000 bar (14500 psi) makes it ideal for this application. Built for permanent pressures up to 500 bar (7250 psi), its rugged stainless steel housing is shrunk onto the ceramic sensing face for a gas-tight, IP 68 seal. Its long operating distance of up to 3 mm keeps it safe from moving parts. It resists temperatures up to 100°C and is rated for more than 1 million pressure cycles, ensuring long-term reliability.

31st Jan 2019 S. Abd

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