A rotating device for producing pressure by expansion of a-pressurized process substance is provided. The rotating device includes a U-channel structure arranged to be rotatable around an axis of a shaft. The U-channel structure includes an expansion point arranged at a periphery of the rotating device, a sinking channel for delivery of the pressurized process substance to the expansion point, a rising channel for delivery of the expanded process substance from the expansion point to a regulating valve for a delivery of the expanded process substance under a higher pressure than that of the pressurized process substance through an outlet channel to an energy recovery device. The rotating device is connected to driving devices in order to rotate the U-channel structure around the axis of the shaft.