JP3022240B2 - Cage valve and method of processing cage valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cage valve for adjusting a flow rate of a fluid in a pipe and a method for processing the cage valve.

[0002]

2. Description of the Related Art A conventional cage valve is disclosed in, for example,
There is one disclosed in JP-A-7-192677. Hereinafter, such a conventional cage valve will be described with reference to the drawings. FIG.
Is a longitudinal sectional view showing a conventional cage valve, and FIG. 10 is a longitudinal sectional view showing a main part of the conventional cage valve. In the figure, a cage valve 1 is provided with a valve body 2 and an upper lid 4 joined to a top opening of the valve body 2 by bolts 3, and inside the valve body 2, a partition wall 5 separates two flow paths 6 and 7. Has been established. And
Both flow paths 6 and 7 are joined to a pipe (not shown) by a flange, and the fluid is configured to flow into the flow path 6 from the direction indicated by the arrow A in the figure.

An outer peripheral edge of a lower end of a cylindrical cage 10 is fitted in a valve seat opening 8 opened in a partition 5, and an upper end is provided to be sandwiched between a valve body 2 and an upper lid 4. ing. At the lower end of the cage 10, an inflow port 11 communicating with the upstream flow path 6 is opened coaxially with the cage 10, and the downstream flow path 7 is provided on the side wall of the cage 10.
A plurality of outlets 12 communicating with the outlet are opened.

An upper valve seat 13 and a lower valve seat 14 are formed above and below the outlet 12 along the inner peripheral wall of the cage 10, respectively.

[0005] A plurality of packings 21 are provided on the upper lid 4 by being pressed by a packing retainer 22, and a valve shaft 23 is supported by the upper lid 4 via the packing 21 so as to be vertically movable. A shaft button 24 connected to a driving unit (not shown) and moving the valve shaft 23 up and down is fixed to an upper end of the valve shaft 23 with a nut 25. A valve plug 26 is provided at a lower end of the valve shaft 23. It is fixed and fitted by the knock pin 27.

The valve plug 26 is formed in a cylindrical shape with a bottom and opens downward, and is supported in the cage 10 with a predetermined gap from the inner peripheral wall of the cage 10 so as to be able to advance and retreat. The valve plug 26 has seating portions 26a and 26b which can be engaged with the upper valve seat 13 and the lower valve seat 14 formed in the cage 10, respectively. The inner surface 26c of the opening end of the valve plug 26 is chamfered largely to form a trumpet shape as a whole. Further, a through hole 28 communicating with the inside of the cage 10 is formed in the ceiling surface of the valve plug 26.

Next, the operation will be described. In the cage valve 1 formed as described above, the fluid flowing into the cage 10 from the inflow port 11 flows out of the outflow port 12 to the downstream flow path 7, and the flow rate is adjusted by moving the valve plug 26 up and down. This is performed by changing the opening area of the outlet 12.

[0008]

Since the conventional cage valve 1 is configured as described above, in order to make the valve plug 26 freely reciprocate in the cage 10, due to its structure, the cage 10 and the valve plug A predetermined clearance is required between the valve plug 26 and the valve plug 26, and even when the valve plug 26 is completely closed due to the clearance, fluid leakage (hereinafter, referred to as "clearance flow") occurs. There was a problem.

In order to solve such a problem, there has been provided means for further narrowing the clearance over the entire inner peripheral wall of the cage 10 or the entire outer peripheral wall of the valve plug 26. However, the clearance between the cage 10 and the valve plug 26 is provided. There is a problem that dust or foreign matter gets into the gap and the valve plug 26 cannot move forward and backward in the cage 10.

On the other hand, when the opening degree of the valve plug 26 is 100%, the lower valve seat 14 of the cage 10 and the valve plug 26
When the clearance is narrowed over a range corresponding to about 10% of the stroke length L formed by the lower end of the cylinder, it is difficult to suppress the clearance flow because the flow resistance (pressure loss) is small. There was a problem.

Further, in order to solve the above two problems, FIG.
The cage valve shown in FIG. 1 was also provided. Here, FIG. 11 is a partial sectional view showing a main part of another conventional cage valve. That is, in such a cage valve, by providing the extending portion 26d at the distal end portion of the valve plug 26, the fitting at that portion is enhanced.

However, in such means, the total length of the valve plug 26 is increased, the value of the valve passing flow rate at the maximum opening (hereinafter referred to as "Cv value") is reduced, and a high-speed fluid jet is used. Collide with the extended portion 26d, and the instability of the flow such as separation or reattachment is repeatedly excited, and as a result, there is a problem that the stem vibrates.

As described above, while avoiding the vibration of the stem, a high Cv value and a high clearance
It was struggling to provide cage valves with reduced flow.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is possible to avoid the vibration of the stem and to reduce the vibration.
An object is to obtain a cage valve having a high v value and a reduced clearance flow.

Another object of the present invention is to provide a cage valve processing method for obtaining such a cage valve.

[0016]

According to a first aspect of the present invention, there is provided a cage valve in which a gap between an inner peripheral wall of a cage and an outer peripheral wall of a valve plug is reduced only near a lower valve seat of the cage. of the inner diameter in the vicinity of the lower valve seat is obtained by forming smaller than the inner diameter of the other near the bottom valve seat of said cage.

According to a second aspect of the present invention, there is provided a cage valve in which a gap between an inner peripheral wall of a cage and an outer peripheral wall of a valve plug is reduced only near a lower valve seat of the cage. The inner diameter is formed smaller than the inner diameter other than near the lower valve seat of the cage, and the outer diameter near the lower part of the valve plug is formed larger than the outer diameter other than near the lower part of the valve plug. .

A cage valve according to a third aspect of the present invention is the cage valve according to the first or second aspect, wherein the cage valve extends upward from a lower valve seat of the cage over a range corresponding to a tight tolerance forming length. The inner diameter of the valve plug is made smaller, or the outer diameter of the valve plug is made larger upward from the lower end of the valve plug over a range corresponding to the tight tolerance forming length.

According to a fourth aspect of the present invention, in the cage valve according to the first to third aspects, the lower end portion of the fluid passage window is formed by a length corresponding to about 5% of the stroke length. It is located above the lower valve seat of the cage.

According to a fifth aspect of the present invention, there is provided a method for machining a cage valve, wherein a circumferential machining groove is provided at a position where the inner diameter of the cage starts to be reduced or a position where the outer diameter of the valve plug starts to increase. , And is processed to a predetermined diameter with the processing groove as a boundary.

[0021]

[Action] cage valves in the invention of claim 1, since the inner diameter near the lower valve seat of the cage is smaller than the inner diameter of the other near the bottom valve seat of said cage, the inner peripheral wall and the valve plug of the cage gap between the outer peripheral wall is reduced only in the vicinity of the lower valve seat of said cage Therefore, clearance furo
-The Cv value can be kept high and the stem
Can also be avoided.

In the cage valve according to the second aspect of the present invention, the inner diameter near the lower valve seat of the cage is formed smaller than the inner diameter other than near the lower valve seat of the cage, and the outer diameter near the lower portion of the valve plug. Since the diameter is formed larger than the outer diameter other than near the lower part of the valve plug, the gap between the inner peripheral wall of the cage and the outer peripheral wall of the valve plug is reduced only near the lower valve seat of the cage, and the vibration of the stem is reduced. A cage valve having a high Cv value and a reduced clearance flow is obtained while avoiding the same.

According to the third aspect of the present invention, the cage valve is formed such that the inner diameter of the cage is reduced upward from a lower valve seat of the cage over a range corresponding to a tight tolerance forming length, or a lower end portion of the valve plug. Since the outer diameter of the valve plug is increased over a range corresponding to the strict tolerance forming length from above, the gap between the inner peripheral wall of the cage and the outer peripheral wall of the valve plug is reduced only in this range, and the stem is reduced. To obtain a cage valve having a high Cv value and a reduced clearance flow while avoiding the vibration of the cage valve.

In the cage valve according to the fourth aspect of the present invention, the lower end portion of the fluid passage window is positioned above the lower valve seat of the cage by a length corresponding to about 5% of the stroke length. The fluid passage window is closed to a valve opening corresponding to about 5% of the length, and a cage valve with reduced clearance flow is obtained.

According to a fifth aspect of the present invention, there is provided a cage valve machining method, wherein a circumferential machining groove is provided at a position where the inner diameter of the cage starts to be reduced or a position where the outer diameter of the valve plug starts to be increased. Since processing is performed to a predetermined diameter using the processing groove as a boundary, processing at the boundary is facilitated.

[0026]

【Example】

Embodiment 1 FIG. An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view showing the relationship between the tolerance of the cage and the tolerance of the valve plug, FIG. 2 is a longitudinal sectional view showing the main part of the cage valve according to one embodiment of the present invention, and FIG. FIG. 4 is a graph showing the flow characteristics of a cage valve according to an embodiment of the present invention. In FIG. 4, corresponding parts shown in FIGS. The description will be omitted, and different components will be described.

The relationship between the tolerance of the cage 10 and the tolerance of the valve plug 26 is as shown in FIG. 1. In each of the above figures, D is the inner diameter of the cage 10, and d is the valve plug 26.
, Β, ε are tolerances. L is the "stroke length" defined by the lower valve seat 14 of the cage 10 and the seat 26b of the valve plug 26 when the opening of the valve plug 26 is 100%, as shown in FIG.

In this embodiment, the lower valve seat 14 of the cage 10 is
The inner diameter D of the cage 10 is formed to be small only over a range corresponding to one fifth of the stroke length L from above. That is, the outer diameter d of the valve plug 26 is
When the cage 10 is formed in the tolerance range of α to −β, the inner diameter D of the cage 10 other than the range corresponding to １ ／ L is formed in the tolerance range of + ε to 0, and further, the cage in the range corresponding to ５ L. The inner diameter D of 10 is formed within a tolerance range of + (ε−β) / 2 to −α / 2.

In this embodiment, the cage 10
Is set to a range in which the inner diameter D of the
, But is not limited to this embodiment.
The length may be in the range of “strict tolerance forming length” which is a length corresponding to L to 1 / 3L.

The reason why the "strict tolerance forming length" is set is as follows. That is, as described above, 1 /
If the tolerance is narrowed in the range of 3L to L, dust or foreign matter gets into the gap between the cage 10 and the valve plug 26, so that the valve plug 26 cannot move forward and backward in the cage 10, and 1 / 5L This is because even if the tolerance is narrowed within the range below, the flow resistance (pressure loss) is small and the effect of suppressing the clearance flow cannot be expected.

Next, the operation will be described. In the cage valve 1 formed as described above, the fluid that has flowed into the cage 10 from the inflow port 11 flows out of the outflow port (fluid passage window) 12 to the flow path 7 on the downstream side. This is performed by moving the plug 26 up and down to change the opening area of the outlet 12.

Further, according to this embodiment, the flow characteristics as shown in FIG. 4 can be obtained. That is, the one according to the prior art shown by the broken line has a low range ability (Rb
30: 1), a high range ability (Rb 75: 1) performance indicated by a solid line can be obtained.

As described above, since the inner diameter D of the cage 10 is formed to be small in a range corresponding to 1 / 5L, the case where the opening degree of the valve plug 26 is 0% (L = 0). Even so, the clearance flow from the portion can be reduced. Also, as in the prior art,
To reduce the flow, the extension 2
Since there is no need to provide the 6d, the Cv value can be increased, and vibration of the stem can be avoided.

Embodiment 2 FIG. Next, another embodiment will be described with reference to the drawings. FIG. 5 is a longitudinal sectional view showing a main part of a cage valve according to another embodiment of the present invention. In this embodiment, the outer diameter d of the valve plug 26 is increased only over a range corresponding to one-fifth of the stroke length L upward from the seating portion 26b of the valve plug 26. That is, cage 1
When an inner diameter D of 0 is formed within a tolerance range of + ε to 0,
The outer diameter d of the valve plug 26 is formed in a tolerance range of -α to -β outside the range corresponding to 1 / 5L, and-(β-ε) / 2 to -α in the range corresponding to 1 / 5L. / 2 tolerance range.

In the above description, the valve plug 26
The range for increasing the outer diameter d of the
However, the present invention is not limited to this embodiment, but may be a range of "strict tolerance forming length" which is a length corresponding to 1 / 5L to 1 / 3L.

As described above, according to this embodiment, the outer diameter d of the valve plug 26 in the range corresponding to 1/5 L
The clearance can be reduced because
Therefore, even when the opening degree of the valve plug 26 is 0% (L = 0), the clearance flow from this portion can be reduced. Also, as in the case of the first embodiment, Cv
The value can be increased, and vibration of the stem can be avoided.

Embodiment 3 FIG. Further, another embodiment will be described with reference to the drawings. FIG. 6 is a longitudinal sectional view showing a main part of a cage valve according to another embodiment of the present invention. This embodiment reduces the inner diameter D of the cage 10 only over a range corresponding to one fifth of the stroke length L upward from the lower valve seat 14 of the cage 10, and reduces the valve plug 26. Seating part 26b
The outer diameter d of the valve plug 26 is formed to be large only over a range corresponding to one fifth of the stroke length L from above. That is, the inner diameter D of the cage 10 in the range corresponding to 1 / 5L is formed within a tolerance range of + β / 2 to 0, and the outer diameter d of the valve plug 26 in the range corresponding to 1 / 5L is- It is formed within a tolerance range of β / 2 to −α / 2.

In the above description, the range in which the inner diameter D of the cage 10 is formed to be small and the outer diameter d of the valve plug 26 is formed to be large has been described as a range corresponding to １ ／ L. However, the present invention is not limited to this embodiment.
The length may be in the range of “strict tolerance forming length” which is a length corresponding to L to 1 / 3L.

As described above, according to this embodiment, the inner diameter D of the cage 10 is made smaller and the outer diameter d of the valve plug 26 is made larger in the range corresponding to 1 / 5L. Therefore, the clearance at only this portion can be reduced, and the opening of the valve plug 26 is 0% (L = 0).
Even in the case of (1), the clearance flow from the portion can be reduced. In addition, the Cv value can be increased, and the vibration of the stem can be avoided.

Embodiment 4 FIG. Next, another embodiment will be described with reference to the drawings. FIG. 7 is a side view showing an arrangement position of an outflow port of a cage valve according to another embodiment of the present invention. In this embodiment, the lower end of the outlet 12 is set at the stroke length L of 5 mm.
% Of the lower valve seat 1 of the cage 10 by a length corresponding to about
4 is located above.

According to this embodiment, the outflow port 12 is closed by the valve plug 26 to a valve opening corresponding to about 5% of the stroke length L, and the clearance flow is reduced.

Therefore, according to this embodiment, the flow characteristics as shown in FIG. 4 can be obtained. That is, the one according to the prior art shown by the broken line has a low range ability (Rb
30: 1), a high range ability (Rb 100: 1) performance indicated by a dashed line can be obtained.

Embodiment 5 FIG. FIG. 8 is a longitudinal sectional view showing a valve plug according to one embodiment of the present invention. In this embodiment, a cage valve is provided in which a circumferential machining groove 30 is provided at a position where the inner diameter D of the cage 10 starts to be reduced, and the valve plug 26 is machined to a predetermined diameter with the machining groove 30 as a boundary. It relates to a processing method. The machining groove 30 is provided in the valve plug 26.
Is provided at a position corresponding to about 1 / 5L upward from the seating portion 26b of the first section, and is formed in a size of about R1 to R3.

According to this embodiment, the valve plug 26 can be easily machined to a predetermined diameter with the machining groove 30 as a boundary.

This embodiment can be used in the first to fourth embodiments.

[0046]

As is evident from the foregoing description, according to the first aspect of the present invention, since the inner diameter near the lower valve seat of the cage and configured to form smaller than the inner diameter of the other near the bottom valve seat of said cage , the gap between the inner wall and the valve plug peripheral wall of the cage is reduced only in the vicinity of the lower valve seat of said cage, this
Therefore, the clearance flow is reduced and the Cv value is increased.
There is an effect that it is possible to obtain a cage valve that can be maintained and can also avoid the vibration of the stem .

According to the second aspect of the present invention, the inner diameter of the cage near the lower valve seat is formed smaller than the inner diameter of the cage other than the lower valve seat, and the outer diameter near the lower portion of the valve plug is reduced. Since the valve plug is formed so as to be larger than the outer diameter other than near the lower portion, the gap between the inner peripheral wall of the cage and the outer peripheral wall of the valve plug is reduced only near the lower valve seat of the cage, and the vibration of the stem is reduced. It is possible to obtain a cage valve having a high Cv value and a reduced clearance flow while avoiding it.

According to the third aspect of the present invention, in the cage valve according to the first or second aspect, the inner diameter of the cage extends upward from a lower valve seat of the cage over a range corresponding to a tight tolerance forming length. Is formed to be smaller or the outer diameter of the valve plug is formed larger from the lower end of the valve plug to a range corresponding to the length of the tight tolerance, so that the inner peripheral wall of the cage and the valve plug are formed. The gap with the outer peripheral wall is reduced only in this range, so that a cage valve having a high Cv value and a reduced clearance flow can be obtained while avoiding vibration of the stem.

According to the fourth aspect of the present invention, in the cage valve according to any one of the first to third aspects, the lower end of the fluid passage window is extended by a length corresponding to about 5% of the stroke length.
Because it is located above the lower valve seat of the cage,
The fluid passage window is closed to a valve opening corresponding to about 5% of the stroke length, so that a cage valve with reduced clearance flow can be obtained.

According to the fifth aspect of the present invention, a circumferential machining groove is provided at a position where the inner diameter of the cage starts to be reduced or a position where the outer diameter of the valve plug starts to be increased. Is processed to a predetermined diameter with the boundary as a boundary, so that it is possible to obtain a cage valve processing method that facilitates processing at the boundary.

[Brief description of the drawings]

FIG. 1 is a plan view showing a relationship between a tolerance of a cage and a tolerance of a valve plug.

FIG. 2 is a longitudinal sectional view showing a main part of a cage valve according to one embodiment of the present invention.

FIG. 3 is a longitudinal sectional view of a main part showing a valve opening degree of a valve plug.

FIG. 4 is a graph showing a flow rate characteristic of a cage valve according to an embodiment of the present invention.

FIG. 5 is a longitudinal sectional view showing a main part of a cage valve according to another embodiment of the present invention.

FIG. 6 is a longitudinal sectional view showing a main part of a cage valve according to another embodiment of the present invention.

FIG. 7 is a side view showing an arrangement position of an outflow port of a cage valve according to another embodiment of the present invention.

FIG. 8 is a longitudinal sectional view showing a valve plug according to an embodiment of the present invention.

FIG. 9 is a longitudinal sectional view showing a conventional cage valve.

FIG. 10 is a longitudinal sectional view showing a main part of a conventional cage valve.

FIG. 11 is a partial cross-sectional view showing a main part of another conventional cage valve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cage valve 10 Cage 12 Outflow port (fluid passage window) 13 Upper valve seat 14 Lower valve seat 26 Valve plug 26a Seating part 26b Seating part 30 Processing groove D Inner diameter of cage d Outer diameter of valve plug L Stroke length

Claims (5)

(57) [Claims] 1. A cylindrical cage having a fluid passage window formed in a peripheral wall, an upper valve seat and a lower valve seat provided above and below the fluid passage window, and a predetermined gap with the inner wall of the cage. A valve plug which is provided in the cage so as to be able to advance and retreat, and which has a seat portion which can be detachably attached to the both valve seats, wherein a gap between an inner peripheral wall of the cage and an outer peripheral wall of the valve plug is provided. so they only become smaller near the lower valve seat of the cage, the inner diameter near the lower valve seat of said cage formed smaller and than the inner diameter of the other near the bottom valve seat of said cage
A cage valve. 2. A cylindrical cage having a fluid passage window formed in a peripheral wall, an upper valve seat and a lower valve seat provided above and below the fluid passage window, and having a predetermined gap with the inner wall of the cage. A valve plug which is provided in the cage so as to be able to advance and retreat, and which has a seat portion which can be detachably attached to the both valve seats, wherein a gap between an inner peripheral wall of the cage and an outer peripheral wall of the valve plug is provided. The inner diameter of the cage near the lower valve seat is smaller than the inner diameter of the cage other than the lower valve seat so that the inner diameter of the valve plug is smaller only near the lower valve seat of the cage, and An outer diameter near the lower part is formed larger than an outer diameter other than near the lower part of the valve plug. 3. A length corresponding to one fifth to one third of a stroke length formed by a lower valve seat of the cage and a lower end portion of the valve plug when the opening degree of the valve plug is 100%. When the length is defined as "strict tolerance forming length", the inner diameter of the cage is formed to be small over the range corresponding to the tight tolerance forming length upward from the lower valve seat of the cage, or 3. The cage valve according to claim 1, wherein an outer diameter of the valve plug is formed to be larger from a lower end to an area corresponding to a strict tolerance forming length. 4. The system according to claim 1, wherein the lower end portion of the fluid passage window is positioned above the lower valve seat of the cage by a length corresponding to about 5% of the stroke length. cage valve according to any one of claims 3 to. 5. A cylindrical cage having a fluid passage window formed in a peripheral wall, an upper valve seat and a lower valve seat provided above and below the fluid passage window, and a predetermined gap with the inner wall of the cage. And a valve plug which is provided in the cage so as to be able to advance and retreat, and has a valve plug having a seat portion which can be attached to and detached from each of the two valve seats. An inner diameter of the cage, which is smaller than an inner diameter other than near the lower valve seat of the cage, or an outer diameter near the lower portion of the valve plug is larger than an outer diameter other than near the lower portion of the valve plug. A circumferential groove is provided at a position where the outer diameter of the valve plug is started to be reduced or a position where the outer diameter of the valve plug is started to be increased, and then processed to a predetermined diameter with the processed groove as a boundary. Valve processing method.