Abstract: A hydraulic piston engine driven by a lubricant-free, water-based pressure fluid, and comprising an enclosing housing and a piston-connected drive shaft supported by radial journal bearings in bearing bushings. One of the sliding surfaces of the radial journal bearing comprises a recess with a bearing-supporting hydrostatic pressure fluid pocket. The center of the recess is displaced by an angle (.alpha.) in the direction against the direction of rotation of the drive shaft, seen in relation to the geometrical, radial mean point in the high-load area for transmission of the piston forces to the bearing surface via the drive shaft. Hereby a particularly reliable piston motor of the type indicated is provided.

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.

Abstract: A fully functional analyzing unit is included within the fluid tight housing of a dialyzer which is immersed in the medium to be analyzed. An opening in the housing is closed by a dialysis membrane. A channel defining body cooperates with the membrane to define a flow channel. The unit includes a carrier fluid reservoir and a carrier pump for generating a flow of carrier fluid through the flow channel. By dialysis via the membrane, the flow of carrier fluid is transformed into a flow of sample fluid. A detecting device is coupled to detect an analyte in the sample fluid and for generating a corresponding detection signal. Effluent sample fluid is received in a waste reservoir. The device is suitable for in situ real-time measurement of plant nutrient salts in process waters of waste water treatment plants.

Abstract: A hydraulic axial piston machine is disclosed, having a cylinder drum which is mounted for rotation relative to a housing (1), with a bearing (3) having a slide face (4) being arranged between the circumference of the cylinder drum and the housing (1). It is desired that such a machine shall be capable of operating also with fluids that are not such good lubricants as hydraulic oil. For that purpose the slide face (4) is formed by a friction-reducing plastics material and has at least one recess (5, 6, 7) communicating with at least one end edge of the slide face (4).

Abstract: A measuring section for an electromagnetic flowmeter is provided having a metallic measuring tube made of a non-magnetic material, a set of magnetic coils for generating a magnetic field in a direction substantially at fight angles to the direction of flow, an electrode arrangement which is arranged substantially at fight angles to the direction of the magnetic field and substantially at right angles to the direction of flow, and an electrical insulator on the inside of the measuring tube, and also a method for the manufacture of this measuring section. Here, it is desirable for manufacture to be carried out with a relatively high degree of reliability. For that purpose, the insulator is constituted by a surface layer of metal oxide or metal nitride having a thickness of more than 10 .mu.m an on the inside of the measuring tube. The inside of the measuring tube can be oxidized or nitrogenized for that purpose and a metal oxide or a metal nitride is deposited on the resulting oxide or nitride layer.

Abstract: A controlled proportional valve is provided, with a main slide valve section (4) containing a main slide valve, which section controls a flow of fluid between a pump connection (P) connected to a pump (2) and a tank connection (T) connected to a tank (6) and two work connections connected to a load (5) and which generates a load-sensing signal (LS.sub.INT) in dependence on the pressures at the work connections (A, B), and with a compensating slide valve section (3) which controls the pressure across the main slide valve section (4) in dependence on the load-sensing signal (LS.sub.INT). It is desirable to achieve a more rapid response time in a proportional valve of that kind, wherein the control means should be capable of being retrofitted to existing proportional valves. To that end, a control arrangement (10) which controls the pressure of the load-sensing signal (LS.sub.INT) to influence the actual volume flow and/or the actual pressure in the work connections (A, B) is provided.

Abstract: A hydraulic machine is disclosed, with an annular gear with internal teeth and, eccentrically mounted in the annular gear, a gearwheel with external teeth which engage with the internal teeth, the internal teeth comprising one more tooth than the external teeth and the contour of the external teeth being formed by an envelope of a system of generating circles, the midpoints of which lie on a trochoid which, as a rolling circle rolls without slipping on a base circle, can be generated by the movement of a point lying on a radial ray of the rolling circle co-rotating with the rolling circle. A method of producing the contour of a rear wheel of such a machine is also disclosed. In such a machine it is desirable to realize a satisfactory inner seal and low Hertzian stresses. To that end, the spacing of the point from the midpoint of the rolling circle is larger than the radius of the rolling circle.

Abstract: A control valve is disclosed, having a housing which has an input port and an output port that are connected to one another by a flow path in which a throttling device is arranged. It is desirable for such a control valve to be able to hold a volume flow constant, irrespective of the load pressure at the output port. For that purpose, the throttling device comprises a series connection of a first throttle, the passage of which is externally adjustable, and a second throttle, the passage of which is adjustable in dependence on pressure.

Abstract: A mass flowmeter has a flow-through channel (2) and as its measuring section (10) a thin strip (3) which at one end has an oscillation generator generating waves travelling along the measuring section (10) and at the other end has an energy converter (8, 9) acting as oscillation detector for these travelling waves. An evaluating circuit (11) determines the mass flow on the basis of the travelling speeds which are different in and against the direction of flow (X). In particular, only one measuring section (10) is provided, the energy converters (8, 9) of which are operable alternately as oscillation generator and oscillation detector. In this manner, meters of relatively short length and high accuracy can be made.

Abstract: A hydraulic machine is disclosed, with a gearwheel, which has a midpoint (6) and a predetermined number of external teeth, and an annular gear, which has a midpoint (7) offset by an eccentricity (E) with respect to the midpoint (6) of the gearwheel and a number of internal teeth which exceeds by one the number of external teeth, the gearwheel and annular gear orbiting and/or rotating relative to one another and at least the form of the external teeth being created using a set of circles (30, 30'; 35, 35') lying with their midpoints (P1-P6; P1'-P6') on a trochoid (36, 37). It is desirable for the efficiency, service life and noise properties of such a machine to be improved. To that end, at least two trochoids (36, 37), displaced relative to one another in the circumferential direction, are provided for generating a tooth profile, the rolling circles (28, 33) of which and the base circles (27, 32) of which differ from one another.

Abstract: A hydraulic piston machine is proposed, with a cylinder body (1), which comprises at least one cylinder (2) with a piston (3) movable therein, and a control counter-plate (7) which engages the cylinder body (1) by way of a contact surface (6) and, on relative movement between the cylinder body and the control counter-plate parallel to the contact surface, connects the cylinder in dependence upon its position with inlet and outlet channels (11, 12) respectively, the control counter-plate (7) and/or the cylinder body (1) being provided, at least in the region of the contact surface (6, 9), with a friction-reducing layer (13). A machine of that kind should be inexpensive to manufacture yet should operate reliably even when the hydraulic fluid has no or only slight lubricating properties. For that purpose the friction-reducing layer (13) is in the form of an injection-moulded part.

Abstract: An operating device (1) with a top part (2) having an actuating arrangement (5) and a bottom part (3) carrying the top part (2). The top part (2) and bottom part (3) are releasably joined to one another and the actuating arrangement (5) drives a control member (6). In an operating device of this kind it is desirable for the top part (2) to be easily mounted on the bottom part (3) and to be easily detachable therefrom. For that purpose the top part (2) and the bottom part (3) are joined to one another by a bayonet joint (16,18).

Abstract: A hydraulic machine with a piston and slider shoe unit (1) is disclosed, in which the piston (2) and the slider shoe (3) are joined to one another by way of a ball-and-socket joint (4) forming a first contact surface, and the slider shoe (3) lies via the intermediary of a second contact surface on a control surface (9), a friction-reducing layer being arranged on one contact surface. It is desirable for a hydraulic machine of the that kind to be capable of reliable operation even when using hydraulic fluids having only a operation even when using hydraulic fluids having only a poor or no lubricating effect at all, yet to be inexpensive to manufacture. For that purpose, the friction-reducing layer (11) is extended to at least one further contact surface.

Abstract: A hydraulic axial piston machine (1) is disclosed, having a cylinder drum (2) which is mounted rotatably in a housing and comprises at least one cylinder (3) which, on rotation of the cylinder drum (2), passes over control kidneys (15) in a control face. In order to be able to operate such a machine even with hydraulic fluid that has no or only slight lubricating properties, such as, for example, water, and in order to be able to manufacture the machine with few manufacturing steps, the control face is located on the rear flange (9) of the housing, and the control kidneys (15) are formed in a plastics material insert (10) which is arranged in the rear flange (9) of the machine (1).

Abstract: A hydraulic machine is disclosed, having an annular gear with internal teeth and a gearwheel with external teeth mounted eccentrically therein, the internal teeth comprising one more tooth than the external teeth and the teeth of at least one set of teeth being formed by rotatably mounted rollers. It is desirable in such a machine for the internal seal to be improved and wear to be reduced. To that end, each roller has in its surface at least three axially parallel recesses, in which the teeth of the other set of teeth engage.

Abstract: A hydraulic steering arrangement for vehicles is proposed, with a steering motor, a flow amplifier in fluid connection therewith, which amplifies a fluid flow measured by a steering measuring device, at least one sensor, which determines a performance characteristic of the vehicle, and a control device, which changes the amount of fluid supplied to the steering motor in dependence on an output signal of the sensor. In a steering arrangement of that kind, it is intended to correct or adapt the steering behavior to the operational status of the vehicle using simple means. For that purpose, the control device changes the amplification factor of the flow amplifier.

Abstract: A hydraulic axial piston machine is disclosed, having an inclined plate (7), on which a slider shoe (9) of at least one piston slides on relative movement between a cylinder body (2) receiving the piston and the inclined plate (7), and a pressure plate (10) articulated on the cylinder body (2) and holding the slider shoe (9) in engagement with the inclined plate. It is desirable for such a machine also to be operable with a hydraulic fluid that has no lubricating properties. For that purpose, between the pressure plate (10) and the cylinder body (2) there is arranged a bearing element (18) with a bearing surface (19) of plastics material, which slides with low friction on a counterpart (15) made of metal lying against the bearing surface (19).