Abstract: A heat exchanger is provided comprising a stack of heat exchanger plates (1, 1a, 1b, 1c) formed of sheet metal having a three-dimensional structured pattern (2, 3), each heat exchanger plate (1,1a, 1b, 1c) having a groove (10), a gasket (9) being arranged in said groove (10) and resting against an adjacent heat exchanger plate (1a), said groove (10) having a bottom inner surface (11), said inner surface bottom (11) having at least a protrusion (14, 15) directed to said adjacent heat exchanger plate (1a). It is intended to minimize the risk of a leakage. To this end in the region of said protrusion (14, 15) said gasket (9) is compressed more than in a region out of said protrusion (14, 15).

Abstract: The invention concerns a valve arrangement (7) comprising a flow path (11) connecting an inlet (9) and an outlet (10), a closing means (12) arranged in said flow path (11), a resetting means and a first pressure in a first pressure chamber (14) acting in a closing direction on said closing means (12), a pressure of said outlet (10) and a second pressure in a second pressure chamber (18) corresponding to a pressure of said inlet (9) when said closing means (12) is closed acting in opening direction on said closing means (12), said first pressure chamber (14) being connectable to the outlet (10) via an auxiliary valve (13). It is intended to keep small a pressure pulse when opening the valve arrangement (7). This is achieved in that the closing means (12) having a first opening state (A) and a second opening state (B), a flow resistance of said closing means (12) in said first opening state (A) being larger than a flow resistance of said closing means in said second opening state (B).

Abstract: The invention concerns a vane cell machine with a stator and a rotor having radially displaceable vanes arranged in guides, said vanes bearing on an inside of the stator and bordering, together with the rotor, the stator and a side wall, work chambers at each axial end of the rotor. It is endeavoured to provide a vane cell machine that has a good internal tightness, in which the wear is still kept small. For this purpose, in a radially internal area the side wall comprises an insert that is axially movable in the side wall and has a pressure application surface axially inside and axially outside.