JPS59175687A - Adjustment valve - Google Patents

Abstract

PURPOSE:To remove the twisting work due to fluid by constructing a small hole provided on an annular cage of an adjustment valve to cross the radial direction at a certain loss angle and selecting the angle of a neighboring small hole at an equal value to be mutually positive and negative for preventing the jet impact on the inner wall of a casing and the surface of the valve body. CONSTITUTION:At the end part of a valve body guide 18 faced to a valve chest 18, an annular cage 30 is shaped in one body. The cage 30 is coaxial with a valve body 24, and surrounds the valve body 24 in the whole area in the valve chest 14 with a confluence chamber 31 consisting of a fixed gas between. A small hole 32A provided on one neighboring stage of a cage 30 is constructed to cross the radial direction of the cage 30 at a loss angle theta, while a small hole 32B provided on another neighboring stage is constructed to cross the radial direction of the cage 30 at a loss angle -theta.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control valve, and particularly to a control valve suitable for adjusting the pressure and flow rate of high differential pressure fluid, such as those used in start-up bypass valves in steam power plants.

In general, a control valve includes a casing that includes an inlet flow path, an outlet flow path, and a valve chamber, a valve seat formed in the valve chamber of the casing, and a valve seat that is supported by the casing and moves in and out of the valve chamber of the casing with respect to the valve seat. The pressure and flow rate of the fluid flowing in from the inlet flow path are continuously adjusted by a variable restrictor formed between the valve body and the valve seat. and can be discharged from the outlet channel.

By the way, the behavior of the fluid in the valve chamber of the above-mentioned control valve is as follows.
At the same time, the flow velocity reaches its maximum at the throttle part, and the static pressure reaches its minimum, creating a localized high differential pressure at the throttle part.This behavior sometimes causes cavitation and erosion due to the fluid, accelerating wear of the throttle part, and increasing noise. cause the occurrence.

Therefore, conventional methods have been used to alleviate changes in fluid flow velocity and static pressure in the constriction section. A regulating valve has been proposed that has an annular cage with a plurality of holes drilled in the radial direction. Efforts are being made to reduce high differential pressure.

However, in the conventionally proposed control valves mentioned above, a pressure loss is given to the fluid based on the small holes themselves, and in order to obtain a relatively large pressure loss, the small holes are arranged in multiple stages, etc. , it is necessary to make the cage structure complicated and larger, and to increase the cage size and, by extension, the casing size.

For example, the so-called DSS conversion of steam power plants that has been proposed recently ([)aily 5tart and 5hu
t-1) Own) For control valves that are frequently started and stopped in order to accommodate VC, it is not possible to increase the casing thickness from the standpoint of reducing thermal fatigue, and increasing the size of the casing described above is permissible. It cannot be done.

In addition, in the conventionally proposed control valves described above, the small holes provided in the cage are bored in the radial direction of the cage, so that the jet of fluid that has passed through the cage is directed toward the inner wall of the casing or the surface of the valve body. It is perpendicular to the casing, and therefore, it is incident with a large impact force, and there is a possibility that the inner wall of the casing or the surface of the valve body may be easily eroded.

In addition, in the case of a control valve, it is necessary to avoid twisting deformation of the valve body, loosening of the threaded portion between the valve body and its actuator, etc. (and avoid creating a vortex flow of fluid around the valve body).

The present invention has a cage that is small and simple, provides a relatively large pressure loss to the fluid, and does not apply an excessive jet impact to the inner wall of the casing or the surface of the valve body, and the fluid applies a torsional action to the valve body. The purpose of this invention is to provide a control valve that does not cause problems.

To achieve the above object, the present invention includes a casing comprising an inlet flow path, an outlet flow path and a valve chamber, a valve seat formed in the valve chamber of the casing, supported by the casing,
A valve body that is movable in the direction toward and away from the valve seat within the valve chamber of the casing, and a plurality of circumferentially arranged layers in each layer that are arranged coaxially with the valve body within the valve chamber of the casing and defined in the axial direction. an annular cage provided with a small hole at a position, the small hole provided in the cage being formed in a direction intersecting the radial direction of the cage at a certain loss angle;
The loss angles of the small holes adjacent to each other in either the axial direction or the circumferential direction are set to the same value, which is mutually positive and negative.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing a control valve according to the first embodiment of the present invention, FIG. 2 (4) is a sectional view taken along line IIA-11A in FIG. 1, and FIG. It is a sectional view along the It13-nB line.

The casing 111C has, for example, an inlet flow path 12 and an outlet flow path 13 that are orthogonal to each other in the horizontal and vertical directions, and a valve chamber 14 is formed at the intersection of the inlet flow path 12 and the outlet flow path 13. ing.

The valve chambers 14&c of the casing 11 are integrated with the valve seat 15 fixed by a lock nut 16 into which the casing 11ic is screwed. Note that 15A is a valve seat portion, and engagement recesses 17 are formed at equidistant positions in the circumferential direction on the upper end surface of the lock nut 16, in which a screw crown can be held.

Further, a valve body guide 18 is coaxially integrated with the casing 11 with respect to the valve seat 15 while being fixed by a retainer nut 19 screwed into the casing 11 . In addition, between the casing 11 and the valve body guide 18, there is a packing holder 20 supported on the back side by a retainer nut 19.
The gaskets 21 and 22 held by are attached.

The valve body guide 18 integrated into the casing 11
The valve rod 23 is inserted, and the valve body guide 18 is able to guide the valve body 24 integrated with the tip of the valve rod 23 in a sliding state. That is, the valve body 24 is movable within the valve chamber 14 of the casing 11 in the direction toward and away from the valve seat 15, and includes a valve body seat 24A that can be brought into close contact with the valve seat seat portion 15A. There is. In addition, the valve stem 23
A threaded portion 25 is formed at the base end to which a valve opening/closing actuator (not shown) can be connected. Further, a gasket 26 is installed between the valve body guide 18 and the valve stem 23, and the gasket 26 is held under pressure between a gasket retainer 27 and a gasket retainer 29 that is supported on the back by a gasket retainer plate 28. Then, the valve chamber 14 of the valve body guide 18
An annular cage 30 is integrally formed at the end facing the.

The cage 30 is disposed coaxially with the valve body 24 and surrounds the valve body 24 through a merging chamber 31 having a predetermined gap in the entire area within the valve chamber 14 . The cage 30 is provided with small holes 32 at a plurality of positions in the circumferential direction of each level defined in the axial direction. A small hole 3 provided on one adjacent level of the cage 30
2A is formed in a direction intersecting the radial direction of the cage 30 at a loss angle [θ], as shown in FIG.
As shown in B), it is formed in a direction intersecting the radial direction of the cage 30 at a loss angle [-0].

That is, the loss angles of the small holes 32A and 32B that are adjacent to each other in the axial direction of the cage 30 are set to the same value, which is positive and negative to each other.

In addition, at equal positions in the circumferential direction on the lower end surface of the cage 30,
A rotation preventing protrusion 33 is formed which engages with the engagement recess IT of the lock nut 16 and prevents the lock nut 16 from freely rotating.

Next, the operation of this first embodiment will be explained.

By the operation of a valve opening/closing actuator (not shown), the valve stem 23 and the valve body 24 are moved in the axial direction, and a constriction portion consisting of a predetermined gap is formed between the valve body seat portion 24A and the valve seat seat portion 15A. After the fluid flowing into the valve chamber 14 from the inlet channel 12 passes through each small hole 32 of the cage 30, it reaches the confluence chamber 31 formed around the valve body 24, and further flows in the axial direction of the valve body 24. Flow down. The fluid flowing down in the merging chamber 31 in this manner passes through the constriction formed between the valve body 24 and the valve seat 15, and the outlet flow is controlled with its pressure and flow rate adjusted. It is discharged from the passage 13 to the downstream side.

Therefore, in this first embodiment, when the fluid first flows into each small hole 32Vc of the cage 30, the small hole 32 is inclined at a loss angle [θ] [-〇] with respect to the radial direction of the cage 30. Therefore, the following (general formula for head loss h□ due to change in flow path cross-sectional area shown in equation 12). For example, when loss angle θ is 30 degrees, ζ20.7, and θ is 0. This results in a loss increase of 40% compared to the loss coefficient ζ=0.5 in the case of 0.5 degrees.

2 hl-ζ (ding) ・・・・・・・・・
(1) ζ = 0.5 + 0.35 ino 0.2 s
i♂θ ・・・・・・・・・(2) In addition, the above (1)
In the formula, 1 indicates the gravitational acceleration, and ■ indicates the flow velocity of the fluid. That is, in this first embodiment, when the fluid passes through each of the small holes 32 of the cage 3o, the small holes 32 are inclined at a certain loss angle with respect to the radial direction of the cage 3o. The first loss occurs.

Furthermore, when the fluid flows into each small hole 32 of the cage 30,
At the same time that the first loss occurs, the small holes 32A formed in one layer adjacent to each other [inflow flux,
The fluxes flowing into the small holes 32B provided in the other adjacent floor are in contact with each other in the vertical direction, and their flow directions are made to intersect in positive and negative directions with respect to the radial direction of the cage 300. Therefore, due to the friction between the two fluxes, when the fluid flows out from each small hole 32 of the cage 30, the fluid flows into a channel whose cross-sectional area is rapidly expanded, and the following equation (8) is obtained. The third head loss h2 is
resulting in a loss of

Further, when the fluid flows out from each small hole 32 of the cage 30, the flux flowing out from the small hole 32A and the flux flowing out from the small hole 32B are as follows:
In a state in which they are in contact with each other in the vertical direction, the flow directions in their horizontal planes are made to intersect in positive and negative directions with respect to the radial direction of the cage 30, and the flow is changed in the axial direction of the valve body 24, that is, in the downward direction. This results in a fourth loss due to friction and collisions between the two fluxes.

That is, according to this first embodiment, the fluid flows through the cage 30.
When passing through each of the small holes 32, a series of loss mechanisms consisting of the first to fourth losses is formed, and a relatively large pressure loss can be obtained without making the cage 30 complicated or large. Possible.

Further, in this first embodiment, each small hole 3 of the cage 30
Since the fluid flowing out from the valve body 24 collides at an angle θ with respect to the normal to the surface of the valve body 24, the fluid flowing out from the valve body 24 collides with the normal to the surface of the valve body 24, compared to the case where it collides parallel to the normal to the surface, that is, at right angles to the surface. The impact force F in the jet direction that acts on the body 24 is significantly reduced as shown in equation (4) below.

−γ F = (−) Qv cos2θ ・・
(4) For example, the impact force caused by the jet when the jet collides at an angle of 30 degrees to the normal to the surface of the valve body 24 is greater than that when the jet collides parallel to the normal to the surface. This results in a 25% reduction, making it possible to prevent erosion on the surface of the valve body 24. In the above equation (4), γ is the specific weight, Q is the flow rate, and ■ is the speed of the jet flow.

Further, in this first embodiment, when the fluid flows out of each small hole 32 of the cage 30, the small holes 32A adjacent to each other are
The fourth loss occurs due to the mutual friction between the flux flowing out from the small holes 32B and the flux flowing out from the small holes 32A.

The rotational direction of the flux flowing out from 32B is offset, and the application of twisting force to the valve body and valve stem due to the accelerated unidirectional vortex flow around the valve body, which tends to occur in conventional valves, is prevented, and the valve Torsional deformation of rod 23 and valve body 24, valve rod 23
It is possible to reliably avoid the occurrence of loosening of the threaded portion between the threaded portion 25 formed in the valve opening/closing actuator and the valve opening/closing actuator.

That is, according to the regulating valve according to the first embodiment, /''
・The valve seat part 15A has a simple design, gives a relatively large pressure loss to the fluid, and reduces the fluid pressure difference at the throttle part.
, it is possible to reduce wear and noise of the valve body seat portion 24A. In addition, the cage 30 is provided that does not apply an excessive impact of jet flow to the surface of the valve body 24, thereby making it possible to prevent erosion on the surface of the valve body. Furthermore, the valve body 24
(The fluid does not exert a twisting action on the valve body.)

FIG. 3 is a sectional view showing a regulating valve according to a second embodiment of the present invention, FIG. 4 (4) is a sectional view taken along the line IVA-IVA in FIG. 3, and FIG. It is a sectional view taken along the line IVB-IVB, and the same functional parts as in the first embodiment are given the same reference numerals, and the explanation thereof will be omitted.

This second embodiment differs from the first embodiment in that the outlet flow path 13 in the first embodiment is replaced by the inlet flow path 13.
1, the arrangement part of the inlet flow path 12 is set as the outlet flow path 42, and the confluence chamber 31 formed around the valve body 24 by the cage 30 is set as the distribution chamber 43. Note that this second
In the embodiment, a seal holder 44 and a seal 45 held by the seal holder 44 were newly installed between the valve seat 15 and the casing 11.

In the case of this second embodiment, each small hole 32A of the cage 30 is similar to the first embodiment.

The relatively large pressure loss created by the series of pressure loss mechanisms by 32B acts as back pressure at the throttle part formed between the valve seat 15 and the valve body 24, and as a result, the fluid pressure difference at the throttle part increases. This reduction makes it possible to reduce the wear and noise of the valve seat seat portion 15A and the valve body seat portion 24A. Further, the fluid flowing out from each small hole 32 of the cage 30 collides with the inner wall of the casing 11 defining the valve chamber 14 at a certain angle and therefore with an impact force of relatively /J%. It becomes possible to prevent the occurrence of erosion on the inner wall of the Also, if the fluid is in cage 3
Due to mutual friction when flowing into each of the small holes 32A and 32B, the rotational direction of the fluid in the distribution chamber 43 is canceled out, and no vortex flow of the fluid is generated around the valve body 24. Therefore, the fluid does not exert a twisting action on the valve body 24.

FIG. 5 is a sectional view showing a control valve according to a third embodiment of the present invention, FIG. 6 (4) is a sectional view taken along the line VIA-VIA in FIG. 5, and FIG. It is a sectional view taken along the line VIB-4B in the figure, and the same functional parts as in the first embodiment are given the same reference numerals, and the description thereof will be omitted.

This third embodiment differs from the first embodiment in that the valve seat 1
A cage 51 similar to the cage 30 in the first embodiment is integrally formed at the end facing the valve chamber 14 of the valve chamber 5.
The inner diameter portion of the cage 51 and the outer circumferential surface of the valve body 24 are arranged relative to each other so that they can slide into close contact with each other. Here, in the cage 5iVc, small holes 52 are formed at a plurality of positions in the circumferential direction of each floor extending in the axial direction, each of which intersects at a certain loss angle with respect to the radial direction of the cage 51. Each small hole 52A provided in each adjacent floor of the cage 51
, 52B are shown in FIG. 6 (4) and (B).
As shown in , they are the same values that are mutually positive and negative. Note that it is possible to prevent free rotation of the lock nut 16.
De 53 is the recess 1γ for engaging the screw fitting of the lock nut 16.
It is welded to the inner wall of the valve chamber 14 so as to engage with the valve chamber 14 .

Also in the case of this third embodiment, each small hole 52A of the cage 51 is similar to the first embodiment.

52B makes it possible to reduce wear and noise of the valve seat portion 15A and the valve body seat portion 24A.

In this third embodiment, since the inner diameter portion of the cage 51 and the outer circumferential surface of the valve body 24 can be brought into close contact with each other, the relative movement of the valve body 24 with respect to the valve seat 15 causes the valve seat seat to The flow rate is adjusted by both a change in the area of the throttle portion formed by the gap between the portion 15A and the valve body seat portion 24A, and a change in the opening area of the small hole 52 opened by the valve body 24.

FIG. 7 is a sectional view showing a control valve according to a fourth embodiment of the present invention, FIG. 8 (4) is a sectional view taken along line ■A-■A in FIG. 7,
FIG. 8(B) is a cross-sectional view taken along the line ■B-■B in FIG. 7, and FIG. 9 is a cross-sectional view showing a disc forming the cage in FIG. Functional parts that are the same as those in the example are given the same reference numerals, and a description thereof will be omitted.

This fourth embodiment differs from the first embodiment in the following points. That is, the cage 61 connects an annular small hole forming part 63 having small holes 62 on each axial level and an annular small hole forming part 65 having small holes 64 on each axial level with a gap. That is, they are arranged concentrically with the merging chamber 66 interposed therebetween.

Each small hole 62, 64 intersects the cage 610 radially at a loss angle. Here, in each of the small hole forming portions 63, each of the /h holes 62A and 62 of adjacent layers in the axial direction
The loss angles of the small holes 64A and 648 in the axially adjacent layers in each small hole forming portion 65 are also the same value that is positive and negative to each other. ing.

In addition, the small holes 62A (62B) and 64A (659) provided on the same level as the radially adjacent small hole forming portions 63 and 659 are also provided.
The respective loss angles in 4B) have approximately the same value, which is positive and negative to each other. In this fourth embodiment, the inner diameter portion of the cage 61 and the outer peripheral portion of the valve body 24 are able to slide into close contact with each other, as in the third embodiment.

The cage 61 also includes a plurality of discs 67 shown in FIG.
It is formed by laminating in the axial direction. Each disc 67 includes an annular small groove forming part 69 having small grooves 68 at a plurality of positions in the circumferential direction, an annular small groove forming part 71 having small grooves 70 at a plurality of positions in the circumferential direction, and a merging chamber forming the merging chamber 66. The forming portions 72 are provided so as to be concentric with each other. Here, the small grooves 68 and 70 provided in the adjacent small groove forming portions 69 and 71 intersect with each other at substantially the same positive and negative angles with respect to the radial direction of the disk 6T, and under the laminated state of the disk 67, And each small hole forming part 63,65 in the cage 61
It is possible to form each of the small holes 62 and 64. That is,
Each date plate 67 stacked on top of the other is connected to the small hole forming portion 63 .
65, and the cage 610 is formed by the confluence chamber forming part 72.
A merging chamber 66 can be formed.

The cage 61 is held between a support plate 73 that is supported on the back side of the valve seat 15 and a support plate 740 on the valve body guide 18 side.
The back is supported by 6. Engagement recesses 7 are formed at the circumferentially equidistant positions IC on the upper end surface of the lock nut 76, and engagement pins 78 are implanted at circumferentially equidistant positions on the lower end surface of the valve body guide 18, and the engagement The engagement between the recess 77 and the engagement pin 78 prevents the lock nut 76 from freely rotating.

According to the fourth embodiment, in addition to the effects of the first and third embodiments, the fluxes of the fluids that have passed through each of the small holes 62 of the first stage small hole forming section 63 are combined. Once merged in the chamber 66, the flux is guided to each small hole 64 of the second stage small hole forming part 65 so that the rotation direction of the flux is reversed,
It becomes possible to obtain a very large loss effect.

In each of the above embodiments, a case has been described in which the loss angles of the small holes adjacent to each other in the axial direction of the cage are set to the same value, which is mutually positive and negative. However, in one aspect of the present invention, the loss angles of the small holes adjacent to each other in the circumferential direction of the cage may be set to the same value which is positive and negative to each other.

As described above, the present invention includes a casing that includes an inlet flow path, an outlet flow path, and a valve chamber, a valve seat that is formed within the valve chamber of the casing, and a valve seat that is supported by the casing and that is arranged in the valve chamber of the casing relative to the valve seat. A valve body that is movable in directions of approaching and separating; and an annular cage that is arranged coaxially with the valve body in a valve chamber of a casing and that has small holes at a plurality of positions in the circumferential direction of each layer defined in the axial direction. A control valve comprising:
The small holes provided in the cage are formed in a direction that intersects the radial direction of the cage at a certain loss angle, and the loss angles of the small holes that are adjacent to each other at least in either the axial direction or the circumferential direction of the cage are The values are set to have the same positive and negative values. Therefore, according to the present invention, the cage is small and simple, provides a relatively large pressure loss to the fluid, and does not apply an excessive jet impact to the inner wall of the casing or the surface of the valve body, and the cage is small and simple, and the cage is provided with a cage that does not apply an excessive impact of jet flow to the inner wall of the casing or the surface of the valve body. It becomes possible to obtain a control valve that does not apply any torsional action to the valve.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a control valve according to the first embodiment of the present invention, FIG. 2 is a sectional view taken along line MA-IIA in FIG. 3 is a sectional view taken along line nB; FIG. 3 is a sectional view showing a control valve according to a second embodiment of the present invention;
Figure (4) is a sectional view taken along the IVA-IVA line in Figure 3, Figure 4 (B) is a sectional view taken along the ■B-■B line in Figure 3, and Figure 5
The figure is a sectional view showing a control valve according to a third embodiment of the present invention, FIG. 6 (4) is a sectional view taken along the line VIA-VIA in FIG. 5,
) in Figure 6 is VIB-■B# in Figure 5! A cross-sectional view along
FIG. 7 is a cross-sectional view showing a control valve according to a fourth embodiment of the present invention, FIG. 8 (4) is a cross-sectional view taken along the line ■A-■A in FIG.
FIG. 8(B) is a cross-sectional view taken along the line ■B--■B in FIG. 7, and FIG. 9 is a cross-sectional view showing a disc forming the cage of FIG. 7 taken out. 11°°Casing, 12.41...Inlet channel, 13
゜42...Outlet flow path, 14...Valve chamber, 15...Valve seat, 24...Valve body, 30,51.61...Cage,
32.32A, 32B, 52.52A, 52B,
62.62A, 62B, fy'4.64A, 548
...Small hole, 63.65...Small hole forming part, 67゛...
Disc, 68.70... Small groove, 69.71... Small groove forming part, 72... Merging chamber forming part. Agent Patent Attorney Osamu Shiokawa

Claims (1)

[Scope of Claims] (1) A casing including an inlet flow path, an outlet flow path, and a valve chamber; a valve seat formed in the valve chamber of the casing; A valve body that is movable in the direction of approaching and separating, and a valve body that is arranged coaxially with the valve body within the valve chamber of the casing, and /J'l holes are provided at a plurality of positions in the circumferential direction of each layer defined in the axial direction. In the control valve, the small hole provided in the cage is formed in a direction intersecting the radial direction of the cage at a certain loss angle, and A control valve characterized in that the loss angles of the adjacent small holes are the same value that is positive and negative. (2. In the control valve according to claim 1,
The cage has a plurality of annular pore-forming parts each having a pore on each level in the axial direction, which are arranged concentrically with no gaps between them, and each of the small holes provided in the same tier of the adjacent pore-forming parts. The loss angles of the control valves are assumed to have approximately the same value, which is positive and negative. (8) Permissible % In the control valve according to claim 2, the cage is formed by laminating a plurality of discs in the axial direction, and each disc has a plurality of small grooves each having a plurality of small grooves at a plurality of positions in the circumferential direction. It includes annular small groove forming parts that are concentric with each other and a merging chamber forming part that is carved between adjacent small groove forming parts, and each small groove provided in the adjacent small groove forming parts extends in the radial direction of the disk. A control valve in which a plurality of annular small hole forming portions with gaps between them are formed by respective small groove forming portions of mutually laminated disks that intersect with each other at substantially the same positive and negative angles.