JP5631166B2 - Steam stop valve - Google Patents

Description

  The present invention relates to a steam stop valve that is installed at the inlet of a turbine such as a thermal power generation turbine or a nuclear power generation turbine and permits or blocks the flow of steam from a boiler or the like to the turbine.

  As a steam stop valve that is installed at a turbine inlet of a thermal power generation turbine, a nuclear power generation turbine or the like and permits or shuts off the flow of steam from a boiler or the like to the turbine, for example, disclosed in Patent Document 1 It has been known.

JP 2000-39076 A

As shown in FIG. 4, the steam stop valve 41 disclosed in Patent Document 1 or the like has a valve body (not shown) attached to one end (the upper end in FIG. 4) as a valve seat (not shown). And a valve rod bush 43 that functions as a sliding tube for the valve rod 42.
In the middle of the valve stem 42 in the longitudinal direction (axial direction) and the middle of the valve stem bush 43 in the longitudinal direction (axial direction), the valve body retreats from the valve seat (separates and moves away), and the valve chamber ( When a steam flow path (not shown) formed in the interior of the valve rod (not shown) is fully opened, it contacts (abuts) each other and moves (moves) to one of the valve stems 42 (upward in FIG. 4). ) Are formed in an annular shape (around one round) in the circumferential direction.

  The inclined surface 42a is tapered from the one end (upper end in FIG. 4) side to the other end (lower end in FIG. 4) side, that is, at the other end of the valve stem 42. 4 is a conical surface (tapered surface) that tapers from one side to the other end side, and the inclined surface 43a extends from one end (upper end in FIG. 4) to the other end (lower end in FIG. 4). ) Side of the valve rod bush 43, that is, a conical surface (taper surface) that tapers from the other end side to the one end side.

An outer peripheral edge (outer peripheral end) of a (first) step portion 42b extending along the radial direction is continuously provided (connected) at one end (upper end in FIG. 4) of the inclined surface 42a. The other end of the small-diameter portion 42c (in FIG. 4) formed in an annular shape (around one round) along the circumferential direction with a constant width (height) and a constant outer diameter at the inner peripheral edge (inner peripheral end) of 42b. The lower end is continuously provided (connected), and the (second) step portion 42d extending in the radial direction is provided at one end (the upper end in FIG. 4) of the small diameter portion 42c. The inner peripheral edge (inner peripheral end) is continuously provided (connected), and the outer peripheral edge (outer peripheral end) of the stepped portion 42d is a medium diameter having a constant outer diameter larger than the outer diameter of the small diameter portion 42c. The other end of the portion 42e (the lower end in FIG. 4) is provided continuously (connected).
On the other hand, a large-diameter portion 42f having a constant outer diameter that is larger than the outer diameter of the medium-diameter portion 42e is continuously provided at the other end (lower end in FIG. 4) of the inclined surface 42a ( It is connected).

One end (upper end in FIG. 4) of the inclined surface 43a is formed in a cylindrical shape along the circumferential direction and the axial direction with a constant inner diameter (an inner diameter slightly larger than the outer diameter of the medium diameter portion 42e). The other end (the lower end in FIG. 4) of the small diameter hole 43b is continuously provided (connected).
On the other hand, the other end of the inclined surface 43a (the lower end in FIG. 4) is continuously provided with an inner peripheral edge (inner peripheral end) of the (first) step portion 43c extending in the radial direction (connection). In addition, the outer peripheral edge (outer peripheral end) of the stepped portion 43c is annularly formed around the circumferential direction with a constant inner diameter (larger) and a constant inner diameter that is larger than the inner diameter of a large-diameter hole 43f described later. One end of the formed enlarged diameter portion 43d (upper end in FIG. 4) is continuously provided (connected), and the other end of the enlarged diameter portion 43d (lower end in FIG. 4). The outer peripheral edge (outer peripheral end) of the (second) step portion 43e extending along the radial direction is continuously provided (connected), and the inner peripheral edge (inner peripheral end) of the step portion 43e is constant. Inner diameter (larger than the inner diameter of the small diameter hole 43b, smaller than the inner diameter of the enlarged diameter portion 43d, and less than the outer diameter of the large diameter portion 42f) The larger inner diameter) in the circumferential direction and the large-diameter hole 43f bored along the axial direction in the cylindrical end (upper end) is continuously provided (connection 4).

  However, in the steam stop valve 41 having such a valve stem 42 and the valve stem bush 43, the middle diameter portion 42e and the small diameter hole 43b, which have a slight gap, are provided on the upstream side of the inclined surfaces 42a and 43a. During this time, a fine scale contained in the vapor accumulates, and the medium diameter portion 42e is fixed (sticked) to the small diameter hole 43b so that the valve stem 42 cannot move or the sliding resistance of the valve stem 42 is large. There was a problem of becoming too much.

  Further, in a state where the inclined surface 42a and the inclined surface 43a are in contact with each other, (high) surface pressure necessary to ensure the sealing performance is applied to the inclined surfaces 42a and 43a. Therefore, creep occurs in the inclined surfaces 42a and 43a exposed to high-temperature steam, and the step portion 42b, the small diameter portion 42c, and the step portion are formed at the other end portion of the small diameter hole 43b as shown by a broken line in FIG. A step 43c and a diameter-expanded portion at one end of the large-diameter portion 42f as shown by a broken line in FIG. 5B or a deformation that enters the space S1 formed by 42d (projects toward the space S1). Deformation that enters into the space S2 formed by the portion 43d and the stepped portion 43e (projects toward the space S2) occurs, so that the valve stem 42 stops moving or the sliding resistance of the valve stem 42 becomes too large. There was a problem.

  This invention is made in view of such a situation, Comprising: It is providing the steam stop valve which can avoid that a valve stem stops moving or the sliding resistance of a valve stem becomes large too much. Objective.

The present invention employs the following means in order to solve the above problems.
The steam stop valve according to the present invention functions as a valve body bush formed by a valve chamber and including a valve body, a valve rod for moving the valve body forward and backward with respect to a valve seat, and a sliding tube of the valve rod. A valve stem bushing that is formed inside the valve chamber by retreating from the valve seat to one side in the longitudinal direction of the valve stem and in the longitudinal direction of the valve stem bush. A steam stop valve in which a first inclined surface that is in contact with each other when the steam flow path is fully open and restrains the movement of the valve stem to the one side is formed in an annular shape in the circumferential direction; One end of a second inclined surface that extends from the one end side of the valve stem to the other end side is continuously provided at the other end of the first inclined surface of the valve stem, and the valve stem bush The other end from the one end side of the valve stem bush to one end of the first inclined surface One end of the second inclined surface as a diverging toward the side is provided continuously.

According to the steam stop valve of the present invention, the first inclined surface of the valve stem and the inclined surface of the valve stem bush are in contact with each other (that is, the valve body is retracted from the valve seat (separated and moved away). In a state where the steam flow path formed inside the valve chamber is fully open), a (high) surface pressure necessary to ensure the sealing performance is applied to these first inclined surfaces. Therefore, creep occurs in these first inclined surfaces exposed to high-temperature steam, for example, deformation as shown by a broken line in FIG. 3A occurs in the second inclined surface 7b of the valve stem bush 7, Deformation indicated by a broken line in FIG. 3B occurs on the second inclined surface 6 f of the valve stem 6.
However, as shown in FIG. 3A, the deformation (most of the deformation) generated in the second inclined surface 7b of the valve stem bush 7 is formed by, for example, a step portion 6b, a small diameter portion 6c, and a step portion 6d. The deformation (most of the deformation) formed on the outer side in the radial direction of the space S3 and generated in the second inclined surface 7b does not enter the space S3.
Further, as shown in FIG. 3B, the deformation (most part) occurring in the second inclined surface 6f is, for example, the radius of the space S4 formed by the step portion 7e, the enlarged diameter portion 7f, and the step portion 7g. The deformation (most of the deformation) formed on the inner side in the direction and generated in the second inclined surface 6f does not enter the space S4.
As a result, it is possible to avoid the valve stem 6 from moving and the sliding resistance of the valve stem 6 from becoming too large.

  In the steam stop valve, one end of a third inclined surface that tapers from one end side to the other end side of the valve stem bush is continuously provided at one end of the second inclined surface of the valve stem bush. It is more preferable that it is used.

  According to such a steam stop valve, the third inclined surface is provided on the inner peripheral side (radially inner side) of the valve stem bush located on the upstream side of the first inclined surface of the valve stem bush, Since the gap between the third inclined surface and the valve stem is wider (larger) than the conventional one (for example, the one shown in FIGS. 4 and 5A), the third inclination Even if a fine scale contained in the steam is deposited between the surface and the valve stem, the sliding resistance of the valve stem can be reduced compared to the conventional one, It can be avoided that the sliding resistance of the valve stem becomes too large.

The steam stop valve according to the present invention functions as a valve body bush formed by a valve chamber and including a valve body, a valve rod for moving the valve body forward and backward with respect to a valve seat, and a sliding tube of the valve rod. to a valve stem bushing, the valve stem inclined surface in the middle in the longitudinal direction of the valve stem is formed annularly in the circumferential direction, the valve stem bush inclined surface circumference halfway through in the longitudinal direction of the valve stem bushing The valve stem inclined surface and the valve stem bush inclined surface are formed in an annular shape along the direction, and the valve body retreats from the valve seat to one side, and a steam flow path formed inside the valve chamber when fully opened, contact each other, a steam valve you restrain movement of the to one of the valve stem, the valve stem bush, on the one side of the valve stem bushing inclined surface the inclined surface is provided, wherein the inclined surface, prior to the valve stem inclined surface of said valve stem The gap between the diameter and the inclined surface in the one side is provided so as to be tapered toward the opposite side of the one from the one side.

According to steam stop valve according to the present invention, the inner peripheral side of the valve stem bush located on the upstream side of the valve rod bushing inclined surface of the valve stem bush (radially inward), inclined slopes are provided, inclined slope those gap between the valve stem of a conventional (e.g., those shown in FIGS. 4 and FIG. 5 (a)) because it is wider than (is greater), between the inclined slope and a valve stem Even when fine scale contained in the vapor accumulates, the sliding resistance of the valve stem can be reduced compared to the conventional one, and the valve stem stops moving or the sliding resistance of the valve stem increases. It is possible to avoid becoming too much.

  According to the present invention, there is an effect that it is possible to avoid the valve stem from moving and the sliding resistance of the valve stem from becoming too large.

It is sectional drawing which shows the whole structure of the steam stop valve which concerns on one Embodiment of this invention. It is a figure which expands and shows the principal part of FIG. It is a figure which expands and shows the principal part of FIG. It is a figure which expands and shows the principal part of the conventional steam stop valve. It is a figure which expands and shows the principal part of FIG.

Hereinafter, a steam stop valve according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3.
FIG. 1 is a cross-sectional view showing the overall configuration of the steam stop valve according to the present embodiment, FIG. 2 is an enlarged view of the main part of FIG. 1, and FIG. 3 is an enlarged view of the main part of FIG. It is.

  The steam stop valve according to the present invention is installed at a turbine inlet of a thermal power generation turbine, a nuclear power generation turbine or the like, and allows or blocks the flow of steam from a boiler or the like to the turbine. These are called “stop valves”, “main shut-off valves”, “main steam source valves”, and the like.

As shown in FIG. 1, the steam stop valve 1 according to this embodiment includes a valve body bush 4 that is formed by a valve chamber 2 and encloses a valve body 3, and the valve body 3 moves forward and backward with respect to a valve seat 5. And a valve stem bush 7 that functions as a sliding tube for the valve stem 6.
In addition, the code | symbol 8 in FIG. 1 shows the turbine inlet, and the code | symbol 9 has shown the steam flow path formed in the inside of the valve chamber 2. FIG.
Moreover, the solid line arrow in FIG. 1 has shown the flow direction of (main) steam.

  As shown in FIG. 2, the valve body 3 (see FIG. 1) is connected to the valve seat 5 (see FIG. 1) in the middle in the longitudinal direction (axial direction) of the valve stem 6 and in the longitudinal direction (axial direction) of the valve stem bush 7. (See FIG. 1) retreating (separating, retreating away), and when the steam flow path 9 (see FIG. 1) formed inside the valve chamber 2 (see FIG. 1) is fully opened, Inclined surfaces 6a and 7a that restrain the movement (movement) of the valve stem 6 toward one side (upward in FIGS. 1 and 2) are formed in an annular shape (round and round) along the circumferential direction. .

  The (first) inclined surface 6a is tapered (end-spreading) from one end (upper end in FIG. 2) side to the other end (lower end in FIG. 2) side of the valve stem 6. 2 is a conical surface (tapered surface) that tapers from the other end side to the one end side, and the (first) inclined surface 7a is the other end from the one end (upper end in FIG. 2) side of the valve stem bush 7 It is a conical surface (tapered surface) that is tapered toward the end (lower end in FIG. 2) and tapered from the other end side to the one end side of the valve stem bush 7.

  One end of the inclined surface 6a (the upper end in FIG. 2) is continuously provided (connected) with an outer peripheral edge (outer peripheral end) of a (first) step portion 6b extending in the radial direction. At the inner peripheral edge (inner peripheral end) of 6b, the other end (in FIG. 2) of the small-diameter portion 6c formed in a ring shape (one round and round) along the circumferential direction with a constant width (height) and a constant outer diameter. The lower end is continuously provided (connected), and the second end portion 6d extending in the radial direction is provided at one end (the upper end in FIG. 2) of the small diameter portion 6c. The inner peripheral edge (inner peripheral end) is continuously provided (connected), and the outer peripheral edge (outer peripheral end) of the stepped portion 6d is a medium diameter having a constant outer diameter larger than the outer diameter of the small diameter portion 6c. The other end of the portion 6e (the lower end in FIG. 2) is continuously provided (connected).

  On the other hand, the other end (lower end in FIG. 2) of the inclined surface 6a extends from one end (upper end in FIG. 2) to the other end (lower end in FIG. 2). One end (upper end in FIG. 2) of the tip end (second end) of the valve stem 6 is tapered (second end) 6f that is tapered from the other end side to the one end side (conical surface: tapered surface). A large-diameter portion 6g having a constant outer diameter larger than the outer diameter of the medium-diameter portion 6e is provided (connected) continuously, and is at the other end (lower end in FIG. 2) of the inclined surface 6f. It is provided continuously (connected).

  One end (upper end in FIG. 2) of the inclined surface 7a is tapered from one end (upper end in FIG. 2) side to the other end (lower end in FIG. 2) side ( 2), that is, the other end (lower end in FIG. 2) of the (second) inclined surface (conical surface: taper surface) 7b tapering from the other end side of the valve stem bush 7 to the one end side. Provided (connected) continuously, one end (upper end in FIG. 2) of the inclined surface 7b is continuous with the inner peripheral edge (inner peripheral end) of the (first) step portion 7c extending in the radial direction. The outer peripheral edge (outer peripheral end) of the stepped portion 7c is connected to the other end (the lower end in FIG. 2) from the one end (the upper end in FIG. 2) side. Taper from the other end side to the one end side of the valve stem 6 (ie, the end wide) ) And a (third) inclined surface (conical surface: the other end of the tapered surface) 7d (lower end in FIG. 2) are provided continuously (connection).

  On the other hand, the other end (lower end in FIG. 2) of the inclined surface 7a is continuously provided with an inner peripheral edge (inner peripheral end) of a (second) step portion 7e extending in the radial direction (connection). In addition, the outer peripheral edge (outer peripheral end) of the stepped portion 7e is annularly formed around the circumferential direction with a constant width (height) and a constant inner diameter that is larger than the inner diameter of the large-diameter hole 7h described later. One end of the formed enlarged diameter portion 7f (upper end in FIG. 2) is continuously provided (connected), and the other end of the enlarged diameter portion 7f (lower end in FIG. 2). The outer peripheral edge (outer peripheral end) of the (third) step part 7g extending along the radial direction is continuously provided (connected), and the inner peripheral edge (inner peripheral end) of the step part 7g is constant. Around the inner diameter (an inner diameter that is larger than the inner diameter of the small diameter hole 7b, smaller than the inner diameter of the enlarged diameter portion 7f, and slightly larger than the outer diameter of the large diameter portion 6g). And a large diameter hole 7h drilled in the cylindrical shape along the axial direction one end (connected) continuously provided (the upper end in FIG. 2).

  According to the steam stop valve 1 according to the present embodiment, the stepped portion 7c and the inclined surface 7d are provided on the inner peripheral side (radially inward) of the valve rod bush 7 located on the upstream side of the inclined surface 7a. Since the gap between the inclined surface 7d and the middle diameter portion 6e is wider (larger) than the conventional one (for example, the one shown in FIGS. 4 and 5A), the inclined surface 7d. Even when a fine scale or the like contained in the vapor is deposited between the inner diameter portion 6e and the middle diameter portion 6e, the sliding resistance of the valve stem 6 can be reduced as compared with the conventional one, and the valve stem 6 moves. It can be avoided that the sliding resistance of the valve stem 6 becomes too large.

According to the steam stop valve 1 according to the present embodiment, the inclined surface 6a and the inclined surface 7a are in contact with each other (that is, the valve body 3 (see FIG. 1) is retracted from the valve seat 5 (see FIG. 1)). In a state where the steam flow path 9 (see FIG. 1) formed inside the valve chamber 2 (see FIG. 1) is fully open (separated and moved away), it is necessary to ensure the sealing performance. (High) surface pressure is applied to the inclined surfaces 6a and 7a. Therefore, creep occurs on the inclined surfaces 6a and 7a exposed to high-temperature steam, and deformation as shown by the broken line in FIG. 3A occurs on the inclined surface 7b, and as shown by the broken line in FIG. 3B. Deformation occurs on the inclined surface 6f.
However, as shown in FIG. 3A, the deformation (most of the deformation) that occurs in the inclined surface 7b is formed on the outer side in the radial direction of the space S3 formed by the step portion 6b, the small diameter portion 6c, and the step portion 6d. The deformation (most part) generated in the inclined surface 7b is prevented from entering the space S3.
Further, as shown in FIG. 3B, the deformation (most of the deformation) generated in the inclined surface 6f is formed on the inner side in the radial direction of the space S4 formed by the step portion 7e, the enlarged diameter portion 7f, and the step portion 7g. The deformation (most part) generated in the inclined surface 6f is prevented from entering the space S4.
As a result, it is possible to avoid the valve stem 6 from moving and the sliding resistance of the valve stem 6 from becoming too large.

Note that the present invention is not limited to the above-described embodiment, and can be modified and changed as necessary.
For example, in the above-described embodiment, the other end of the inclined surface 7d is continuously provided (connected) to the outer peripheral edge of the stepped portion 7c. However, the outer peripheral edge of the stepped portion 7c has a constant inner diameter and a circumferential direction. Alternatively, one end of a hole drilled in a cylindrical shape along the axial direction may be continuously provided (connected).

  In the above-described embodiment, one end of the inclined surface 7b and the other end of the inclined surface 7d are connected via the stepped portion 7c, but the stepped portion 7c is eliminated and one end of the inclined surface 7b is connected. The other end of the inclined surface 7d may be directly connected.

DESCRIPTION OF SYMBOLS 1 Steam stop valve 2 Valve chamber 3 Valve body 4 Valve body bush 5 Valve seat 6 Valve rod 6a (First) inclined surface 6f (Second) inclined surface 7 Valve rod bush 7a (First) inclined surface 7b ( (Second) inclined surface 7d (third) inclined surface (second inclined surface)
9 Steam flow path

Claims (3)

A valve body bush that is formed by the valve chamber and encloses the valve body, a valve rod that moves the valve body forward and backward with respect to the valve seat, and a valve rod bush that functions as a sliding tube of the valve rod;
In the middle of the valve stem in the longitudinal direction and in the middle of the valve stem bush in the longitudinal direction, the valve body retreats from the valve seat to one side, and the steam flow path formed inside the valve chamber is fully opened. A first stop surface that is in contact with each other and restrains the movement of the valve stem to the one side when formed, and is a steam stop valve formed annularly along the circumferential direction,
The other end of the first inclined surface of the valve stem is continuously provided with one end of a second inclined surface that extends from one end side to the other end side of the valve rod,
One end of the first inclined surface of the valve stem bush is continuously provided with one end of a second inclined surface that extends from the one end side to the other end side of the valve stem bush. Steam stop valve.   One end of the second inclined surface of the valve stem bush is continuously provided with one end of a third inclined surface that tapers from one end side to the other end side of the valve stem bush. The steam stop valve according to claim 1. A valve body bush formed by the valve chamber and enclosing the valve body;
A valve stem that advances and retracts the valve body relative to the valve seat;
It has a valve stem bush that functions as a sliding tube for this valve stem,
In the middle of the longitudinal direction of the valve stem, a valve stem inclined surface is formed in an annular shape along the circumferential direction,
Stem bushing inclined surface is formed annularly in the circumferential direction during developing in the longitudinal direction of the valve stem bush,
The valve stem inclined surface and the valve stem bush inclined surface come into contact with each other when the valve body retreats from the valve seat to one side and the steam flow path formed inside the valve chamber is fully opened. Te, a steam stop valve you restrain movement of said to one of the valve stem,
The valve stem bush is provided with an inclined surface on the one side of the valve shaft bush inclined surface ,
The inclined surface, so that the gap between the valve the valve stem inclined surface than diameter portion and the inclined surface in said one side of the rod tapers toward an opposite side of the one from the one side of the The steam stop valve provided in the.

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