NOVELTY - Device for supplying a fluid with varying pressure comprises a supply device (1) comprising a connecting channel (6) for supplying hydraulic fluid, a switching means (5), which connects the connecting channel optionally with a first pressure reservoir (3) with a first pressure or with a second pressure reservoir (4) with a second pressure, and an operating device comprising an operating chamber for receiving the fluid, a supply channel, which is closed by a first closure device, and a discharge channel, which is closed by a first closure device.    USE - The device is useful for supplying a fluid with varying pressure.    DETAILED DESCRIPTION - Device for supplying a fluid with varying pressure comprises a supply device (1) comprising a connecting channel (6) for supplying hydraulic fluid, a switching means (5), which connects the connecting channel optionally with a first pressure reservoir (3) with a first pressure or with a second pressure reservoir (4) with a second pressure, and an operating device comprising an operating chamber for receiving the fluid, a supply channel, which is closed by a first closure device, and a discharge channel, which is closed by a first closure device. The supply channel and the discharge channel respectively open into the operating chamber. The operating chamber is pressurized on the secondary side of a piston arrangement by a chamber piston. The primary side of the chamber piston is subjected to a compressive force, which corresponds to a pressure present in the connecting channel. An INDEPENDENT CLAIM is also included for operating the device comprising supplying the pressure, which is alternately increased, reduced and synchronized in the connecting channel of the supply device by periodic operation of the switching means, preferably by continuous or intermittent rotation of the shaft, to the fluid, which is to be processed, of the operating chamber, and simultaneously removing the processed fluid from the operating chamber.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic representation of the device.    Supply device (1)    First pressure reservoir (3)    Second pressure reservoir (4)    Switching means (5)    Connecting channel (6)