The method involves pressuring fluid from a pump (2) i.e. piston pump, and supplying the fluid with a certain volume stream to a discharge opening (11). The pump is switched in an automatic manner from an operating mode for pressure generation into another operating mode for production of suction effect for suction of fluid, during interruption of the volume stream. The suction operation is realized so long till a signal is generated, during completion of interruption of the volume stream. A control device (24) is utilized for adjusting time duration of the two operating modes. An independent claim is also included for a device for production of a volume stream for realization of a fluid-stream for cutting/rinsing the rigid material and soft material.
