Screw expander with variable volume controlled by the pressure ratio, and plant for recovering electrical energy from heat with a screw expander

Abstract

In order to adapt to different operating conditions a screw expander, comprising an expander housing with a screw rotor chamber arranged therein, two screw rotors arranged in the screw rotor chamber and mounted rotatably in the expander housing, which screw rotors intermesh with their screw contours in order to receive working medium supplied by means of a high-pressure chamber arranged in the expander housing and in order to discharge said medium in the region of a low-pressure chamber arranged in the expander housing, and a generator driven by the screw rotors, it is proposed that the screw expander has at least one control slide, which is arranged in a slide channel of the expander housing and is adjacent to both screw rotors with slide wall surfaces, which control slide is movable in a displacement direction parallel to the screw rotor axes and is thereby configured to influence the final volume and/or the initial volume, and that a slide drive is provided for moving the control slide into different slide positions.