JPH0234533Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Industrial application field] The present invention relates to a high differential pressure regulating valve.

[Prior Art] Generally, high differential pressure control valves such as pump recirculation valves for process control in thermal power plants, nuclear power plants, etc.
It is used under extremely harsh conditions of high differential pressure and high temperature.

Therefore, in the high differential pressure control valve as described above, when the fluid passes through its minimum restriction part, the fluid velocity increases and at the same time the pressure rapidly decreases, which causes the fluid to drop below the saturation pressure of the fluid. A drop can cause cavitation and damage to valve components.

Conventionally, in order to prevent the above-mentioned cavitation from occurring, a control valve 1 has been proposed which is provided with multi-stage fluid restriction ports, as shown in FIGS. 9 and 10. The control valve 1 includes a casing 5 including an inlet passage 2, an outlet passage 3, and a valve chamber 4, a valve seat 6 formed inside the valve chamber 4, and a valve seat 6 with the inside of the valve chamber 4 facing the valve seat 6. It has a valve body 7 that moves in the direction of approaching and separating and can adjust the valve opening degree. Further, the control valve 1 has a cylindrical cage 8 fixed inside the valve chamber 4, and this cage 8 is arranged so that the valve body 7 can be moved downstream of the shutoff region formed by the valve seat 6 and the valve body 7. The port 9 is provided with multiple stages in the direction. In addition, control valve 1
In this embodiment, a plurality of multistage obturators 10 arranged on the inner surface of the cage 8 are integrally connected to the valve body 7. Each obturator 10 corresponds to each port 9 of the cage 8, and allows the fluid passage areas of these ports 9 to be mutually adjusted at a uniform opening degree. In addition, the control valve 1
In order to flow the fluid that has flowed into the inner surface of the cage 8 from the upstream port 9 to the next port 9, it is necessary to release the fluid to the outer surface of the cage 8, and the area is equal to or larger than the port area. The cage 8 is equipped with a fluid escape window 11 that is always open.

Therefore, the fluid flowing into the control valve 1 is
As shown by arrows in FIG. 10, after passing through the shutoff area between the valve seat 6 and the valve body 7, the fluid passes through the fluid relief windows 11 and ports 9 in each stage in sequence, and the pressure is gradually reduced and the fluid flows out. This prevents the pressure within the control valve 1 from dropping below the saturation pressure of the fluid, making it possible to prevent cavitation from occurring.

[Problems to be Solved by the Invention] However, in the above-mentioned control valve 1, it is essential that the cage 8 is provided with a number of fluid escape windows 11 corresponding to the number of stages of the ports 9. Here, the cage 8 is a pressure-resistant container that receives fluid pressure, and the port 9 and the fluid escape window 11 must be spaced apart from each other by a certain distance or more for strength reasons.

Therefore, in the case of the control valve 1, the length l of the device becomes considerably large, which causes difficulties in manufacturing processability, disassembly and assembly workability, and on-site installation workability.

An object of the present invention is to enable the device to be made smaller without impairing decompression performance.

[Means for Solving the Problems] The present invention includes a casing including an inlet flow path, an outlet flow path, and a valve chamber, a valve seat formed in the valve chamber, and a valve chamber that is moved toward and away from the valve seat. In the high differential pressure regulating valve, the valve seat and the valve element form a plurality of stages of ports in the direction in which the valve element moves. The cylindrical cage provided on the downstream side of the shut-off area and the adjacent ports of the cage are arranged alternately so that the fluid areas of these ports can be adjusted to each other at a uniform opening. It has an inner obturator and an outer obturator located on the inner and outer sides respectively, and the cage is integrally connected to the valve body, and the fluid passage area of each port is continuously adjusted according to changes in the valve opening. It is designed to be adjustable.

[Operation] According to the present invention, fluid that flows into the inner surface of the cage from the upstream port flows out to the outer surface of the cage from the next port, and then flows to the inner surface of the cage from the subsequent downstream port. Repeat the inflow flow. At this time, each port has an aperture function, and none functions as an escape window as in the conventional example. That is, each port is
The fluid passage area is adjusted by the inner obturator or the outer obturator, and the pressure of the fluid can be gradually reduced. In other words, in the present invention,
There is no need to provide an opening in the cage like a conventional fluid escape window that does not have a throttling function, making it possible to reduce the length of the device when trying to maintain the same number of stages of decompression performance as before. .

[Embodiment] FIGS. 1 to 4 are cross-sectional views showing a high differential pressure regulating valve 20 according to an embodiment of the present invention. Control valve 20
has a casing 24 with an inlet channel 21 and an outlet channel 22 and a valve chamber 23. The casing 24 consists of an upper casing 24A and a lower casing 24B that are integrated with each other. A cage guide 25 is fixedly arranged in the valve chamber 23 of the lower casing 24B. The cage guide 25 includes a valve seat 26 that communicates the inlet flow path 21 and the outlet flow path 22. A valve rod 27 is slidably supported by the upper casing 24A. Valve stem 27
includes a valve body 28 that is movable toward and away from the valve seat 26. The valve body 28 is capable of forming a shutoff region between the valve body 28 and the valve seat 26 .

A cylindrical cage 29 housed within the cage guide 25 is integrally connected to the lower end of the valve body 28 . The cage 29 has a plurality of stages (four stages in this embodiment) in the direction of movement of the valve body 28, from the first port to the fourth port.
Equipped with ports 30A to 30D, those ports 3
0A to 30D can be arranged downstream of the shutoff region formed by the valve seat 26 and the valve body 28.

A support rod 31 that is integrally connected to the lower end of the cage guide 25 is disposed inside the cage 29 . A fluid passage 32 is formed in a portion of the support rod 31 that is coupled to the cage guide 25.

The cage guide 25 has a first port 30A and a third port 30A.
Outer obturators 33, 34 corresponding to port 30C
It is equipped with Further, the support rod 31 includes inner obturators 35 and 36 corresponding to the second port 30B and the fourth port 30D. Each of the above obturators 33~
Reference numeral 36 allows the fluid passage areas of the corresponding ports 30A to 30D to be mutually adjusted at uniform opening degrees.

Note that a portion of the valve rod 27 that protrudes from the casing 24 is provided with a threaded portion 37 to which a valve opening/closing actuator can be connected. Further, a packing 38 is disposed between the intermediate portion of the valve stem 27 and the upper casing 24A.

In the above control valve 20, the valve seat 26 and the valve body 2
When the shutoff area formed by 8 is opened from the fully closed state of FIG. 1 as shown in FIG. 2, the first port 30A
flows into the inner surface of the cage 29 through the second port 30B, and then flows out to the outer surface of the cage 29 through the second port 30B.
Next, it flows into the inner surface of the cage 29 through the third port 30C, and then flows into the cage 29 through the fourth port 30D.
It flows out to the outer surface side of 9. At this time, each port 30A
~30D, as shown in FIG. 5, the fluid passing area Y is continuously adjusted according to the change in the valve opening degree X by the throttling action of the corresponding obturators 33 to 36, and the fluid is gradually passed through. Reduce the pressure to allow it to flow out.

According to the above-mentioned control valve 20, there is no need to provide an opening in the cage 29 like a conventional fluid relief window that does not have a throttling function, and when trying to secure pressure reduction performance with the same number of stages as the conventional one, the length of the device can be reduced. It becomes possible to downsize the.

In addition, in the case of the above-mentioned control valve 20, each port 3
Cavitation can be more reliably prevented from occurring by setting the opening areas of ports 0A to 30D in a mutual relationship as shown in FIG.

In addition, in implementing the present invention, FIGS. 6 and 7
As shown, each port 4 to the cage 40
By appropriately changing the shapes of 0A to 40D,
The relationship between the valve opening degree X and the fluid passage area Y of each port can be changed as shown in FIG.

Further, in implementing the present invention, for example, in the above-mentioned control valve 20, the outer obturators 33, 34 and the inner obturators 35, 36 are integrally connected to the valve body 28, and the cage 29 is fixed to the casing 24 side. It's okay to be hot.

[Effects of the invention] As described above, the present invention includes a casing including an inlet flow path, an outlet flow path, and a valve chamber, a valve seat formed in the valve chamber, and a valve seat that moves the valve chamber toward and away from the valve seat. In the high differential pressure regulating valve, the valve seat and the valve element form a plurality of stages of ports in the direction in which the valve element moves. The cylindrical cage provided on the downstream side of the shut-off area and the adjacent ports of the cage are arranged alternately so that the fluid areas of these ports can be adjusted to each other at a uniform opening. It has an inner obturator and an outer obturator located on the inner and outer sides respectively, and the cage is integrally connected to the valve body, and the fluid passage area of each port is continuously adjusted according to changes in the valve opening. It is designed to be adjustable. Therefore, there is no need to provide the cage with an opening such as a fluid escape window that does not have a throttling function, and it is possible to downsize the device without impairing pressure reduction performance.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing a control valve according to an embodiment of the present invention, Fig. 2 is a sectional view showing a different operating state from Fig. 1, and Fig. 3 is a view taken along the - line in Fig. 1. , FIG. 4 is a sectional view taken along the - line in FIG. 3, FIG. 5 is a diagram showing the flow rate characteristics of the control valve in FIG. 1, FIG. 6 is a front view showing a modified example of the port shape, and FIG. The figure is a sectional view taken along the - line in Figure 6, and Figure 8 is a cross-sectional view along the - line in Figure 6.
Diagram showing the flow rate characteristics depending on the port shape shown in Figure 9.
10 is a cross-sectional view showing a conventional control valve, and FIG. 10 is a cross-sectional view showing the control valve of FIG. 9 in different operating states. 20... Control valve, 21... Inlet channel, 22...
Outlet flow path, 23... valve chamber, 24... casing,
26...valve seat, 28...valve body, 29...cage,
30A to 30D... Port, 33, 34... Outer obturator, 35, 36... Inner obturator, 40...
...cage, 40A-40D...port.

Claims (1)

[Scope of utility model registration request] A casing that includes an inlet flow path, an outlet flow path, and a valve chamber, a valve seat formed within the valve chamber, and a valve that moves toward and away from the valve seat within the valve chamber and can adjust the valve opening degree. A high differential pressure regulating valve comprising a cylindrical cage and a cylindrical cage in which ports forming multiple stages in the direction of movement of the valve body are provided on the downstream side of a shutoff area formed by the valve seat and the valve body. , an inner obturator and an inner obturator located on each of the inner and outer sides of the cage so as to alternately correspond to each of the adjacent ports of the cage and to enable the fluid areas of these ports to be mutually adjusted with uniform opening degrees. A high differential pressure regulating valve, characterized in that the cage is integrally connected to the valve body, and the fluid passage area of each port can be continuously adjusted according to changes in the valve opening degree. .