Abstract: The invention concerns a vane cell machine having a stator and a rotor that is made of a first material, the rotor having guides comprising radially displaceable vanes that rest on an inside of the stator and border work chambers at each axial end of the rotor together with the rotor, the stator and individual stationary side walls, the vanes having, at least at some contact faces with the rotor and the stator, a second material that interacts unfrictionally with the first material. It is endeavoured to keep the wear small. For this purpose, in a radially inner area, the side wall comprises a surface of a third material interacting unfrictionally with the first material and, in a radially outer area a surface made of the first material.

Abstract: The invention concerns a reverse osmosis system (1) with at least one membrane unit (2) comprising an inlet (3), a permeate outlet (4) and a concentrate outlet (5), a high-pressure pump (8) that is connected to the inlet (3), a pressure exchanger (11) comprising at least one high-pressure concentrate connection (HPC), and a booster pump. It is endeavoured to achieve the lowest possible energy consumption. For this purpose, the booster pump is made as a displacement pump (16) that is arranged between the concentrate outlet (5) and the high-pressure concentrate connection (HPC) of the pressure exchanger (11).

Abstract: The invention concerns a reverse osmosis system (1) with a membrane unit (2) comprising an inlet (3), a permeate outlet (4) and a concentrate outlet (5), a high-pressure pump (8) that is connected to the inlet (3), a pressure exchanger (11) connected on its concentrate side (10) to the concentrate outlet (5), and a booster pump between the pressure exchanger (11) and the inlet (3). It is endeavoured to make the energy consumption as small as possible. For this purpose, the booster pump is made as a displacement pump.

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 valve arrangement (1) with a housing (2), an inlet connection (3) and an outlet connection (4), which are connected with each other via a flow path, in which is located a dosing device (5), which has a valve seat (7) and a valve element (6) interacting with the valve seat (7), the valve element (6) being loaded in the direction of the valve seat (7) by a resetting device (8) and being acted upon on the side facing the valve seat (7) by a pressure in a first pressure chamber (9), said pressure corresponding to the pressure in the inlet connection (3), when the dosing device (5) is dosed, and on the side facing away from the valve seat (7) by the pressure in a second pressure chamber (11), which is connected with the outlet connection (4) via a channel arrangement (14), in which is located at least one auxiliary valve (15), and with the first pressure chamber (9) via a throttle (13). It is endeavoured to reliably ensure that the closing device (5) opens.

Abstract: The invention concerns a water-hydraulic machine with at least two mutually movable parts, of which one has a surface of a plastic material with friction-reducing properties. In such a machine it is desired to enable the use of demineralised water. For this purpose, it is ensured that a layer of a carbon-containing material is arranged between the plastics material and the other part.

Abstract: The invention concerns a valve arrangement (1) with a housing (2), an inlet connection (3) and an outlet connection (4), which are connected with each other via a flow path, in which is located a dosing device (5), which has a valve seat (7) and a valve element (6) interacting with the valve seat (7), the valve element (6) being loaded in the direction of the valve seat (7) by a resetting device (8) and being acted upon on the side facing the valve seat (7) by a pressure in a first pressure chamber (9), said pressure corresponding to the pressure in the inlet connection (3), when the dosing device (5) is closed, and on the side facing away from the valve seat (7) by the pressure in a second pressure chamber (11), which is connected with the outlet connection (4) via a channel arrangement (14), in which is located at least one auxiliary valve (15), and with the first pressure chamber (9) via a throttle (13). It is endeavoured to reliably ensure that the closing device (5) opens.

Abstract: The invention concerns a water-hydraulic machine with at least two mutually movable parts, of which one has a surface of a plastic material with friction-reducing properties. In such a machine it is desired to enable the use of demineralised water. For this purpose, it is ensured that a layer of a carbon-containing material is arranged between the plastics material and the other part.

Abstract: A valve is indicated as well as a device for controlling the valve body in a valve, which is special in that the travel of the valve body in the valve housing is insignificantly damped in the opening movement of the valve, and strongly damped in the closing movement of the valve. The valve is therefore distinguished by the fact that especially in connection with pressure media with a low boiling point, the risk of cavitation in the valve and instability in operation is reduced.