Valve arrangement

Abstract

Valve arrangement for a water line with a pressure and / or flow control valve (1) and a throttling device (2) downstream of the pressure and / or flow control valve (1) in the direction of flow, wherein the throttling device (2) is arranged at an outlet (3) of a drain line (6) connected to the outlet side of the pressure and / or flow control valve (1) and has an outer pipe (15) provided with radial outlet openings (14) and an inner pipe (17) arranged inside the outer pipe (15) forming an intermediate space (16) with radial through-openings (18), characterized in that a conical inlet area (20) is provided at the inlet side of the inner pipe (17) and that drainage bores (24) are arranged in the inner pipe (17).

Description

[0001] The invention relates to a valve arrangement for a water pipe according to the preamble of claim 1.

[0002] Such a valve arrangement is known from DE 202 13 940 U1. In the device disclosed therein for controlling and throttling high fluid pressures in systems, a throttling device is arranged downstream of a pressure regulating valve located within a housing. The throttling device has a number of flow channels formed by grooves in several concentric hollow cylinders.

[0003] DE 24 02 774 A1 discloses a throttle valve with a valve cone arranged within a housing and a reflection silencer arranged downstream of the valve cone in the flow direction. The reflection silencer consists of two coaxially arranged perforated cylinders, which are arranged coaxially in a section of the housing adjoining a throttle cross-section.

[0004] In a valve arrangement known from DE 10 2015 108 478 A1, a throttling device designed as a nozzle for reducing cavitation is arranged at the outlet of a pressure and / or flow control valve designed as a ring piston valve. The nozzle, located directly at the outlet opening of the valve housing, has a central through-hole with a cross-section that narrows in the flow direction and several radial passages branching off from the central through-hole. Such a nozzle not only generates a back pressure in the pressure and / or flow control valve that reduces cavitation, but also ensures that the flow in a pipeline connected to the pressure and / or flow control valve is directed to an inner wall of a housing or pipe surrounding the nozzle and is reapplied with minimal turbulence.This can reduce vibrations and the tendency of the pressure and / or flow control valve to cavitate.

[0005] Ring piston valves are used in a wide variety of pressure and flow control applications. They can be used, for example, as bottom drain valves in dams, as flow control or pipe rupture protection valves, as pressure or level control valves, and as flushing and draining valves. In certain applications, suitable venting devices or control inserts can be used to reduce cavitation. Ring piston valves are also frequently used in turbine bypasses, where they are subjected to high differential pressures and high flow velocities. However, venting devices often cannot be installed in these applications because the trapped air would cause pressure oscillations in the downstream piping system.

[0006] The object of the invention is to create a valve arrangement of the type mentioned above which enables a reduction of the tendency to cavitation at a pressure and / or flow control valve at high differential pressures and high flow velocities.

[0007] This problem is solved by a valve arrangement having the features of claim 1. Advantageous embodiments and further developments of the invention are specified in the dependent claims.

[0008] In the valve arrangement according to the invention, the throttling device, located downstream of the pressure and / or flow control valve in the flow direction, is arranged at the outlet of a drain line connected to the outlet side of the pressure and / or flow control valve. The throttling device comprises an outer tube with radial outlet openings and an inner tube with radial through-openings arranged within the outer tube, forming an intermediate space. A conical inlet area is provided at the inlet side of the inner tube. Drainage bores are also arranged in the inner tube. Within the throttling device, the flow of the medium entering the throttling device is redirected, thus reducing the pressure energy and generating a back pressure within the drain line and at the outlet of the pressure and / or flow control valve, thereby reducing the valve's tendency to cavitate.Furthermore, the load on the drain line downstream of the pressure and / or flow control valve can be reduced, and the outlet into a settling basin or similar can be better controlled. The settling basin is not mixed as thoroughly and can therefore be designed with a more compact size.

[0009] In a flow-optimized design, the outlet openings in the outer pipe are axially offset from the through-openings in the inner pipe along a longitudinal axis of the throttling device, so that the water flowing through the through-openings into the space between the pipes can only reach the outlet openings in the outer pipe after being deflected again. This results in particularly effective flow deflection and excellent energy dissipation.

[0010] The outlet openings in the outer pipe and the through-openings in the inner pipe can have a round, elongated, angular or asymmetrical shape.

[0011] In a further advantageous embodiment, the throttling device can include a mounting flange at its lower end for attachment to the bottom of a settling basin or other surface. This allows it to absorb the forces exerted by the flow and the pipework.

[0012] The throttling device can also include an integrated component with a connecting pipe that is slidably inserted into a pipe section at the end of the drain line and radially sealed by a gasket. This allows for the compensation of structural tolerances. The gasket can be located in a connecting flange that is slidable on the connecting pipe.

[0013] In a further particularly advantageous embodiment, a piston axially displaceable between a closed position for closing the through-openings and an open position for opening the through-openings can be arranged in the inner tube. This piston is expediently moved into the open position by the water flowing into the throttling device and into the closed position by a spring. This forces the incoming water to overcome spring pressure before it can flow out through the throttling device. In this way, even at low flow rates, a back pressure is generated at the pressure and / or flow control valve, reducing cavitation. As the degree of opening of the pressure and / or flow control valve increases, the pressure on the piston in the throttling device also increases, so that more through-openings are released for flow with increasing pressure.While in a throttling device without such a piston the back pressure increases with the square of the velocity, an additional piston can generate a nearly constant back pressure at the pressure and / or flow control valve. This reduces the stress and cavitation tendency of the pressure and / or flow control valve.

[0014] The piston is expediently guided so that it can slide on a guide rod arranged centrally in the inner tube and, in the closed position, is pressed by the spring against a stop piece arranged at the upper end of the guide rod.

[0015] Further features and advantages of the invention will become apparent from the following description of preferred embodiments with reference to the drawings. The drawings show: Fig. 1 an embodiment of a valve arrangement for controlling the water drain with a pressure and / or flow control valve and a throttling device; Fig. 2 a first embodiment of a throttling device in a perspective view; Fig. 3 the throttle device of Fig. 2 in a sectional view; Fig. 4 a second embodiment of a throttling device with a throttling element in a closed position and Fig. 5 the throttle device of Fig. 4 with the throttle body in an open position.

[0016] In Fig. Figure 1 shows a valve arrangement for controlling the water discharge in a turbine bypass. The valve arrangement comprises a pressure and / or flow control valve 1, designed here as a ring piston valve, and a throttling device 2 located downstream of the pressure and / or flow control valve 1 in the flow direction. The throttling device 2 is arranged at an outlet 3 of a drain line 6 connected to an outlet side 4 of the pressure and / or flow control valve 1 and leading to a settling basin 5 or the like. In the illustrated embodiment, the drain line 6 is formed by a bend 7 connected to the outlet side 4 of the pressure and / or flow control valve, straight pipe sections 8 and 9 adjoining the bend 7, and a fitting 10 at the outlet 3 of the drain line 6. The pressure and / or flow control valve 1 is connected to a water line (not shown) at an inlet side 11.

[0017] In the Fig. 2 and Fig. Figure 3 shows a first embodiment of a throttling device 2 for generating back pressure at the outlet of the pressure and / or flow control valve 1. The throttling device 2, which is provided with an upper connection flange 12 and a lower retaining flange 13, has an outer tube 15 with radial outlet openings 14 and an inner tube 17 with radial through-openings 18 arranged inside the outer tube 15, forming a space 16. A conical inlet section 20 is provided between the upper connection flange 12 and an inlet opening 19 of the inner tube 17, which is cylindrical in this case. The through-openings 18, which are designed here as holes with a round cross-section, are arranged in the upper half of the inner tube 17 adjacent to the inlet section 20. However, the through-openings 18 can also have a different shape.

[0018] The outer tube 15, arranged around the inner tube 17, comprises a lower cylindrical section and an upper conical section that closes off the annular space 16 formed between the outer tube 15 and the inner tube 17. The space 16 is closed off at the bottom by the lower retaining flange 13. The outlet openings 14, designed here as elongated holes, are located in the cylindrical section of the outer tube 15 below the through-openings 18. The outlet openings 14 can also have different shapes. Advantageously, the outlet openings 14 in the outer tube 15 have a cross-sectional area larger than or equal to that of all through-openings 18 in the inner tube 17. The throttling device 2 can be attached, for example, to the bottom of a settling basin 5 or to another solid surface via bores 21 in the lower retaining flange 13.The upper connection flange 12 also has bores 22 for connecting the throttling device 2 to the drain pipe.

[0019] How particularly from Fig. As can be seen from Figure 3, the outlet openings 14 in the outer pipe 15 are axially offset from the through openings 18 in the inner pipe 17 in the direction of a longitudinal axis 23 of the throttling device 2 such that the water flowing through the through openings 18 into the space 16 can only reach the outlet openings 14 in the outer pipe 15 after being deflected again. The water flowing axially into the inner pipe 17 must first be deflected within the inner pipe 17 before it can reach the space 16 through the radial through openings 18. Due to the axial offset of the through openings 18 relative to the outlet openings 14, the water flowing into the space 16 must then be deflected again before it can flow outwards through the outlet openings 14 in the outer pipe 15. This allows the energy to be dissipated particularly effectively and an increase in pressure within the drain line to prevent cavitation.Drainage is also made possible during operational downtime by several drainage bores 24 arranged around the circumference at the base of the inner pipe 17.

[0020] In Fig. Figure 3 also shows the installation piece 10, to which the throttle device 2 described above is connected at the end of the drain line 6. This installation piece 10 contains a connecting pipe 26, which is attached to the connection flange 12 of the throttle device 2 by means of a flange 25. The connecting pipe 26 is slidably inserted into the pipe section 9 of the drain line 6 and radially sealed by a seal 27. The seal 27, designed as a four-lip seal (quad ring), sits in a connecting flange 28, which is slidably arranged on the connecting pipe 26 and is rigidly connected to an end flange 29 of the pipe section 9. This allows for the compensation of structural tolerances.

[0021] In the Fig. 4 and Fig. 5 is a further embodiment of a throttling device 2 for generating a back pressure at the outlet of the in Fig. Figure 1 shows the pressure and / or flow control valve 1. This throttling device 2 has essentially the same basic structure as the previously described version. Corresponding components are therefore also marked with the same reference numerals and are not described in detail again below.

[0022] In contrast to the previous version, in the one in Fig. 4 and Fig. In the embodiment shown in Figure 5, a piston 31 is arranged inside the inner tube 17, acted upon by a spring 30 against the flow direction. The piston 31 is guided axially displaceably within the inner tube 17 and is held in a position by the spring 30 clamped between the piston 31 and the lower retaining flange 13. Fig. 4 shown closed position pressed. Centrally located inside the inner tube 17 is a guide rod 32, supported on the lower retaining flange 13 and coaxial to the longitudinal axis 23 of the throttling device, on which the spring 30, designed here as a coil spring, and the piston 31 are guided. In the Fig. In the closed position shown in Figure 4, the piston 31 is pressed by the spring 30 against a stop piece 33 located at the upper end of the guide rod 32. In this closed position, the piston 31 lies above the through-openings 18, so that the through-openings 18 are closed by the piston 31.

[0023] As water flows into the throttling device 2, the piston 31 is pushed downwards against the force of the spring 30, opening more or fewer passages 18 depending on the pressure of the incoming water. This allows a nearly uniform back pressure to be generated at the pressure and / or flow control valve 1. Depending on the application, the spring 30 can have a linear or progressive spring characteristic.

Claims

[1] Valve arrangement for a water pipe with a pressure and / or flow control valve (1) and a throttling device (2) arranged downstream of the pressure and / or flow control valve (1) in the direction of flow, wherein the throttling device (2) is arranged at an outlet (3) of a drain pipe (6) connected to the outlet side of the pressure and / or flow control valve (1) and has an outer pipe (15) provided with radial outlet openings (14) and an inner pipe (17) arranged inside the outer pipe (15) forming an intermediate space (16) with radial through-openings (18), characterized by , that a conical inlet area (20) is provided at the inlet side of the inner tube (17) and that drainage bores (24) are arranged in the inner tube (17). [2] Valve arrangement according to claim 1, characterized by, that the outlet openings (14) in the outer tube (15) are offset axially in the direction of a longitudinal axis (23) of the throttling device (2) relative to the through openings (18) in the inner tube (17). [3] Valve arrangement according to claim 1 or 2, characterized by , that the outlet openings (14) in the outer tube (15) and the through openings (18) in the inner tube (17) have a round, elongated, angular or asymmetrical shape. [4] Valve arrangement according to any one of claims 1 to 3, characterized by , that the outlet openings (14) in the outer tube (15) have a larger or equal cross-sectional area than all the through-openings (18) in the inner tube (17). [5] Valve arrangement according to any one of claims 1 to 4, characterized by , that the throttling device (2) includes at its lower end a retaining flange (13) for fastening to a floor (5) or other substrate. [6] Valve arrangement according to any one of claims 1 to 5, characterized by, that the throttling device (2) includes an integrated installation piece (10) with a connecting pipe (25) slidably inserted into a pipe section (9) at the end of the drain pipe (6) and radially sealed via a seal (27). [7] Valve arrangement according to claim 6, characterized by , that the seal (27) is arranged in a connecting flange (28) which is slidable on the connecting pipe (26). [8] Valve arrangement according to any one of claims 1 to 7, characterized by , that in the inner tube (17) a piston (31) is arranged which is axially displaceable between a closed position for closing the through-openings (18) and an open position for opening the through-openings (18). [9] Valve arrangement according to claim 8, characterized by , that the piston (31) can be moved into the open position by the water flowing into the throttling device (2) and into the closed position by a spring (30). [10] Valve arrangement according to claim 9, characterized by , that the piston (31) is slidably guided on a guide rod (32) centrally arranged in the inner tube (17). [11] Valve arrangement according to claim 10, characterized by , that the piston (31) in the closed position is pressed by the spring (30) against a stop piece (33) arranged at the upper end of the guide rod (32). [12] Valve arrangement according to any one of claims 9 to 11, characterized by that the spring (30) has a linear or progressive spring characteristic. [13] Valve arrangement according to any one of claims 1 to 12, characterized by , that the pressure and / or flow control valve (1) is designed as a ring piston valve.

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