JP2977433B2 - Flow control 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 flow control valve which is used, for example, as a steam control valve of a large steam turbine and is suitable for controlling a steam flow.

[0002]

2. Description of the Related Art FIG. 9 shows a known flow control valve for a large steam turbine. That is,
A muffler 2 whose lower end is opened toward the fluid passage from above is fitted into the valve main body casing 1, and the closed upper end bonnet 3 is fixed to the valve main body casing 1 by a plurality of bolts 4. In the side wall of the muffler 2, fine holes 5 are formed in a staggered manner near the lower end opening, and a flow rate adjusting hole 6 is provided in the upper part. A plug member 7 is provided inside the muffler 2, an outer surface of the plug member 7 is in sliding contact with an inner surface of the muffler 2, and two pressure seal rings 8 are fitted into an outer wall of the plug member 7. The inner peripheral surface of the muffler 2 is kept airtight. Also, the bottom 7 of the plug member 7
a, a valve stem 9 extending toward the opposite side of the lower end opening of the muffler 2 and extending from the bonnet 3 at the upper end of the muffler,
The valve stem 9 is connected by, for example, universal joint means, and the valve stem 9 is airtightly supported by a valve stem guide bush 10 provided concentrically inside the muffler 2. Further, a plurality of pressure balance holes 11 are formed in the bottom 7a of the plug member 7.

Next, the operation of the conventional flow control valve having such a configuration will be described. Steam A is the inlet port 1 on the left side of FIG.
The amount of steam flowing from the flow control valve to the lower outlet port 13 in FIG. 9 is determined by the position of the plug member 7 connected to the valve stem 9. That is, the illustrated state shows a state in which the flow of the steam A is almost shut off. However, when the valve stem 9 is pulled up via a driving means (not shown), the plug member 7 following the valve rod 9 is pulled upward, and the plug member 9 is pulled up. Muffler 2 blocked by 7
Is gradually opened, and the steam A passes according to the degree.

[0004]

By the way, in the conventional flow control valve described above, when the plug member 7 is slightly opened slightly upward, the so-called steam A flows from the tip of the muffler 2. It becomes the state of the gap flow A ',
There is a problem that the vibrating of the plug member 7 is reduced. This vibration mode is applied to the bottom 7 of the plug member 7.
Since the connection between the valve shaft 9a and the valve rod 9 is in a pin connection state by a universal joint means or the like, the connection is as shown in FIG.
The role of suppressing the vibration is given only to the two pressure seal rings 8 fitted on the outer wall of the plug member 7, and is not enough to suppress the generated vibration. There was a problem of causing damage.

The present invention has been made to solve such problems of the prior art, and has as its object to provide a flow control valve which prevents vibration of a plug member when the plug member is slightly opened. .

[0006]

According to a first aspect of the present invention, there is provided a flow control valve provided in a fluid passage, comprising a valve body casing and an upper end provided in the valve body casing. Is closed, and the lower end is open toward the fluid passage, and a muffler having a fine hole on the side wall of the opening and a flow rate adjusting hole on the upper side thereof,
An outer surface slidably contacts an inner surface of the muffler, and a plug member having a pressure seal ring on an outer wall, and is coupled to a bottom portion of the plug member, extends toward a side opposite to a lower end opening of the muffler, and extends from an upper end of the muffler. A plug having a valve stem, a valve stem guide bush concentrically provided inside the muffler for hermetically supporting the valve stem, and a guide bush seal ring slidably contacting the outer surface of the valve stem guide bush; A supporting member for supporting an upper part of the member on the outer surface of the valve stem guide bush.

According to a second aspect of the present invention, there is provided a flow control valve provided in a fluid passage, wherein a valve body casing is provided in the valve body casing, an upper end is closed, and a lower end is directed toward the fluid passage. A muffler that is open and has a pore on the side wall of the opening and a flow rate adjusting hole on the top thereof, a plug member having an outer surface slidably in contact with the inner surface of the muffler, and a pressure seal ring on the outer wall; A valve stem coupled to the bottom of the member, extending toward the opposite side of the lower end opening of the muffler and extending from the upper end of the muffler, and provided concentrically inside the muffler for hermetically supporting the valve stem. A valve rod guide bush, a plurality of damping rods having an upper end fixed to the upper end of the muffler and a lower end fixed to the bottom of the plug member. Comprises a damping member which simultaneously contact the inner surface and the outer surface of the valve stem guide bush of the plug member.

[0008]

According to the first aspect of the present invention, the pressure seal ring is provided on the outer wall of the plug member and slidably contacts the inner surface of the muffler, and is provided on the support member above the plug member and slidably contacts the outer surface of the valve stem guide bush. Fluid pressure (for example, steam force) acts on the guide bush seal ring to firmly hold the plug member on the muffler and the valve stem guide bush, so that vibration of the plug member when the plug member is slightly opened is reduced. Can be prevented.

According to the second aspect of the present invention, the damping member attached to the plurality of damping rods provided to extend between the bottom of the plug member and the upper end of the muffler is provided between the inner surface of the plug member and the valve stem. Because it is in contact with the outer surface of the guide bush at the same time,
Even if vibration of the plug member occurs when the plug member is slightly opened, the vibration is suppressed. Since the lower end of each damping bar is fixed to the bottom of the plug member, the rotational movement of the plug member is completely prevented.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a flow control valve according to the present invention will be described below in detail with reference to FIGS. In addition,
In these figures, the same parts as those in FIG. 9 are denoted by the same reference numerals, and description thereof will be omitted.

FIG. 1 is a sectional perspective view showing an embodiment of a flow control valve according to the present invention, and FIG. 2 is a sectional view seen from the front of FIG. That is, in the flow control valve according to the present embodiment, in addition to the conventional configuration shown in FIG. 9, the support member (disk) 21 is slidably contacted with the outer surface of the valve stem guide bush 10 above the plug member 7. At the same time, the guide bush seal ring 22 is fitted on the inner peripheral surface of the support member 21 to maintain airtightness. Accordingly, the plug member 7 is provided with a pressure seal ring 8 that slides on the inner surface of the muffler 2.
And a guide bush seal ring 22 provided on the support member 21 above the plug member 7 and slidably in contact with the outer surface of the valve stem guide bush 10, and is held by the muffler 2 and the valve stem guide bush 10. In addition, the support member 21 includes
A plurality of pressure balance holes 23 are formed.

As prior arts similar to the present invention shown in FIGS. 1 and 2, those described in Japanese Utility Model Laid-Open No. 61-3904 and Japanese Patent Laid-Open No. 63-29367 are known. . That is, Japanese Utility Model Laid-Open No. 61-3904 discloses a steam control valve of a steam turbine in which a chrysanthemum-shaped adjusting wheel having a thin plate and having a sprung action is engaged with the outer peripheral surface of a valve rod guide bush. . However, the adjusting wheel provided in the steam control valve is intended to prevent mechanical rotation, and is not intended to prevent vibration of the plug member in the present invention, and the pressing force is sufficient. Not something. If the adjusting wheel is made strong, there is a risk that the plug member will not move due to biting or the like since the adjusting wheel is in contact at points.

On the other hand, Japanese Patent Application Laid-Open No. 63-29367 discloses a flow control valve having a valve body guide that slides along the outer periphery of a bush. However, this flow control valve
It is intended to improve the concentricity of the bush, and since the valve element guide simply slides around the bush, there is a gap between the two, and this gap cannot be filled. Therefore, the above two prior arts are structurally similar to the present invention, but differ in the purpose and the function and effect of the present invention.

Next, the operation of the flow control valve according to the present invention will be described. 1 and 2 show a state in which the flow of the steam A is almost shut off. However, as the plug member 7 is pulled up, the flow rate of the muffler 2 closed by the plug member 7 is adjusted. The hole 6 is gradually opened, and the steam A flows from the inlet port 12 to the outlet port 13 through the flow rate adjusting hole 6 of the muffler 2.

Here, the reaction force in the assembled state of the adjusting wheel of the prior art and the guide bush seal ring 22 of the present invention is limited to 10 to 50 kg, but in the guide bush seal ring 22 of the present invention, Because of the seal ring, it is possible to hold the plug member 7 with an extremely large force based on the steam pressure difference in addition to the reaction force. That is, for example, the diameter D of the guide bush seal ring 22 is 10 cm, and the height H is 2 cm.
Then, the pressure receiving area A of the guide bush seal ring 22 is

A = πDH = π × 10 × 2 cm ²

Here, since the steam pressure is 60 kg / cm ² and ^two pressure seal rings 8 are provided on the plug member 7, the guide bush seal ring 22 is used as the third seal ring. Assuming that a steam pressure of 1/3 is received by

## EQU2 ## From P = Acm ² × 60 kg / cm ² × 1/3, it becomes about 1200 kg. That is, it can be seen that the force due to the steam force P is so large as to cause no problem when compared with the force generated from the guide bush seal ring 22 or the adjusting wheel alone in the prior art.

FIG. 3 shows a model test result of vibration response acceleration in order to clarify the effect of the present invention. 1 and the present invention shown in FIG. 2 are compared and shown. As is clear from FIG. 3, it was confirmed that the vibration of the plug member 7 was reduced to about 2/3 by installing the guide bush seal ring 22. The frequency also increased about 1.5 times,
It was also confirmed that the rigidity was enhanced.

Next, another embodiment of the present invention will be described with reference to FIGS. FIG. 4 is a cross-sectional perspective view showing another embodiment of the flow control valve according to the present invention, FIG. 5 is a cross-sectional view seen from the front of FIG. 4, and FIG. It is a perspective view which cuts out and shows.

In the flow control valve according to the present embodiment, in addition to the conventional structure shown in FIG. 9, a plurality of vibration damping rods (bolts) 31 are connected to the bonnet 3 at the upper end of the muffler 2 and the bottom 7a of the plug member 7. The upper and lower ends of each damping rod 31 are attached to the bottom 3a of the bonnet 3 and the plug member 7, respectively.
2 and 33 fixed. Further, each damping rod 31 extends through a plurality of holes 35 (see FIG. 6) formed in a single damping disc 34, and the damping disc 3
4 is fixed by upper and lower nuts 36 and 37. The damping disk 34 is disposed so as to simultaneously contact the inner surface of the plug member 7 and the outer surface of the valve stem guide bush 10.

A plurality of pressure balance holes 38 are also formed in the damping disk 34. Further, the lower end of each damping bar 31 can be fixed to the bottom 7a of the plug member 7 by using some of the plurality of pressure balance holes 11 conventionally drilled. However, in this case, it is necessary to make the diameter of the remaining pressure balance holes 11 larger than in the past, and to maintain the total area of the pressure balance holes as in the past.

According to the configuration shown in FIGS. 4 to 6, the mounting member is attached to a plurality of vibration damping rods 31 provided so as to extend between the bottom 7a of the plug member 7 and the upper end (bonnet 3) of the muffler 2. Since the damping disk 34 is simultaneously in contact with the inner surface of the plug member 7 and the outer surface of the valve stem guide bush 10, even if vibration of the plug member 7 occurs when the plug member 7 is slightly opened, the vibration is suppressed. The function and effect are almost the same as those shown in FIGS. Since the lower end of each damping bar 31 is fixed to the bottom 7a of the plug member 7, the rotational movement of the plug member 7 is completely prevented.

FIGS. 7 and 8 show a modification of the embodiment shown in FIGS. 4 to 6. FIG. 7 is a sectional perspective view of a flow control valve according to this modification, and FIG. 8 is a front view of FIG. FIG.

This modification is different from the embodiment shown in FIGS. 4 to 6 in that a plurality of damping rods 3 are used instead of the single damping disk 34.
The vibration damping rings 41 are independently attached to each of the components 1, and these vibration damping rings 41 are arranged so as to simultaneously contact the inner surface of the plug member 7 and the outer surface of the valve stem guide bush 10. With such a configuration, the same operation and effect as those of the configurations shown in FIGS. 4 to 6 can be obtained.

[0024]

As described in detail above, according to the present invention,
In a flow control valve such as a large steam control valve, it can prevent vibration of the plug member when the plug member is slightly opened, prevent the generation of noise due to the vibration and the damage caused by the vibration, and enhance the vibration rigidity. A remarkable effect is achieved.

[Brief description of the drawings]

FIG. 1 is a sectional perspective view showing one embodiment of a flow control valve according to the present invention.

FIG. 2 is a sectional view seen from the front in FIG. 1;

FIG. 3 is a characteristic diagram shown to explain an effect of the present invention.

FIG. 4 is a sectional perspective view showing another embodiment of the flow control valve according to the present invention.

FIG. 5 is a sectional view as viewed from the front in FIG. 4;

FIG. 6 is a perspective view showing a vibration control disk used in the embodiment of FIG.

FIG. 7 is a sectional perspective view of a flow control valve showing a modification of the embodiment of FIG. 4;

8 is a sectional view as viewed from the front in FIG. 7;

FIG. 9 is a sectional perspective view showing a conventional flow control valve.

FIG. 10 is a characteristic diagram showing a vibration mode of a plug member in a conventional flow control valve.

[Explanation of symbols]

 A steam 1 valve body casing 2 muffler 5 pore 6 flow rate adjusting hole 7 plug member 8 pressure seal ring 9 valve stem 10 valve stem guide bush 21 support member 22 guide bush seal ring 31 damping rod 34 damping disc 41 damping Swing ring

Claims (4)

(57) [Claims] In a flow control valve provided in a fluid passage, a valve body casing and an upper end closed in the valve body casing, and a lower end opened to the fluid passage are provided. A muffler having a pore on the side wall of the opening and a flow rate adjustment hole on the top thereof, an outer surface slidingly contacting the inner surface of the muffler, a plug member having a pressure seal ring on the outer wall, and being coupled to the bottom of the plug member, A valve stem extending toward the opposite side of the lower end opening of the muffler and extending from the upper end of the muffler, and a valve stem guide bush concentrically provided inside the muffler for airtightly supporting the valve stem, A support member that has a guide bush seal ring that slides on the outer surface of the valve stem guide bush, and that supports the upper part of the plug member on the outer surface of the valve stem guide bush; Flow control valve, characterized by Bei. 2. A flow control valve provided in a fluid passage, wherein a valve body casing is provided in the valve body casing, an upper end is closed, and a lower end is opened toward the fluid passage. A muffler having a pore on the side wall of the opening and a flow rate adjustment hole on the top thereof, an outer surface slidingly contacting the inner surface of the muffler, a plug member having a pressure seal ring on the outer wall, and being coupled to the bottom of the plug member, A valve stem extending toward the opposite side of the lower end opening of the muffler and extending from the upper end of the muffler, and a valve stem guide bush concentrically provided inside the muffler for airtightly supporting the valve stem, A plurality of damping rods, the upper end of which is fixed to the upper end of the muffler and the lower end of which is fixed to the bottom of the plug member;
A flow control valve, comprising: a damping member that simultaneously contacts an inner surface of the plug member and an outer surface of the valve stem guide bush. 3. The flow control valve according to claim 2, wherein the damping member comprises a single damping disk having a plurality of holes through which a plurality of damping bars are fixed. 4. The flow control valve according to claim 2, wherein the damping member comprises a plurality of damping rings attached to each of the plurality of damping bars.