JPH02150585A - High differential pressure control valve - Google Patents

Abstract

PURPOSE:To secure the smooth on-off operation of a valve body, its sure shutoff state and stable flow controllability by constituting it so as to make a small hole exist even in any position in the axial direction of a cage through the setting of a passage part position of each columnar plate. CONSTITUTION:A fluid flow line is controlled in a small hole 24 of a cage where a fluid flowing into a casing 14 is not closed by a valve body 19, and it is exhausted to the side of an outlet passage 12 by way of a throttle part that a seat surface 20 of the valve body 19 forms in a gap with a seat surface of a valve seat 17. At this time, it is smoothly exhausted in the constant downward direction owing to guide action of the fluid by the small hole 24 of the cage 21, while it is exhausted in reducing its flow velocity by loss action, so that a cavitation growth phenomenon in a very short period caused by storing cavitation vibration will never occur. In consequence, there is no generation of a stick to hinder on-off operation of the valve body 19, securing smooth on-off operation of the valve body, and shutoff operation also becomes smoothed without any resistance, thus a sure shutoff state with no leakage at time of valve fully closing is securable.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a high differential pressure regulating valve suitable for use in a variable pressure startup bypass system of a steam power plant, etc.

[Prior Art] High differential pressure control valves are used in startup bypass systems and the like of commercial boilers. This high differential pressure control valve, as exemplified by the heater bypass valve, is capable of handling a wide range of ultra-high temperatures, from high-pressure cold water to sub-critical or supercritical pressure steam, through the temperature and pressure raising process at the time of boiler startup. It controls the flow rate and pressure of high-pressure fluid, and also functions as a stop valve that shuts off the main steam pipe system on the high-pressure side of the boiler and the flash tank or condenser side on the low-pressure side during normal operation of the boiler. Therefore, it is exposed to extremely harsh usage conditions.

The Japanese and American high differential pressure control valves include 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 has a valve seat formed in the valve chamber of the casing. The valve body is configured to be movable toward and away from the valve body, and the seat surface provided on the valve body is separated from the seat surface provided on the valve seat.

However, when high-pressure chilled water is controlled by a high differential pressure regulating valve such as in recent startup bypass valves, water vaporization occurs directly below the constriction formed between the seat surface of the valve body and the seat surface of the valve seat. , extremely unstable cavities that have grown considerably locally appear and disappear instantaneously, resulting in intense cavitational vibrations.

Conventionally, in order to reduce the above-mentioned cavitation vibration, as described in Japanese Patent Publication No. Sho 48-25333, a cage with a narrow winding flow path was provided in the fluid path flowing around the valve body, and this cage had a labyrinth. proposed a device that provides high resistance loss to the fluid.

[Problems to be Solved by the Invention] However, the conventional device described above has the following problems because the cage is formed by vertically stacking a large number of discs each having grooves. .

(2) The disc constituting the cage may shift, and this may come into contact with the valve body (valve stem), obstructing the smooth opening and closing movement of the valve body, and causing so-called stickiness in the valve body.

(2) In relation to (2) above, there is a risk that the displaced disc will create resistance to the closing operation of the valve body, making it impossible to obtain a reliable shut-off state without leakage when the valve is fully closed.

■Cage pores are not formed between the upper and lower discs. For this reason, the presence of the small holes is discontinuous in the opening/closing direction of the valve body, and when the valve body is located within a certain range between the discs, no change in flow rate can occur. That is, the flow rate characteristics with respect to changes in the opening degree of the valve body become discontinuous, and when controlling the movement of the valve body to control the flow rate, a hunting phenomenon tends to occur, making stable flow control difficult.

The present invention ensures smooth opening/closing operation of the valve body and a reliable shut-off state when reducing cavitation vibration using a cage equipped with small holes that control fluid flow lines flowing around the valve body. The purpose is to ensure flow rate controllability.

[Means for Solving the Problems] The present invention according to claim 1 provides 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, and a valve seat supported by the casing. The valve body is arranged coaxially around the valve body while being supported by the casing, and the valve body is movable in the direction toward and away from the valve seat within the valve chamber of the casing. In a high differential pressure regulating valve, the valve has a cage in which small holes are formed to control fluid flow lines, and the seat surface provided on the valve body is brought into contact with and separated from the seat surface provided on the valve seat. The cage is formed by arranging a large number of columnar plates having fan-shaped cross sections in a ring shape, and the small holes of the cage are formed in the flow passages provided on the side surfaces of each columnar plate. The structure is such that small holes are present at any position in the axial direction of the cage by setting the positions of the flow passages in each columnar plate.

According to a second aspect of the present invention, the flow path portion provided on the side surface of the columnar plate is inclined downward so as to guide the fluid toward the outlet flow path.

According to a third aspect of the present invention, the flow path portion provided on the side surface of the columnar plate is provided with irregularities that cause fluid loss.

[Operation] In the present invention, the fluid characteristics of the fluid flowing into the valve casing are controlled in the small holes of the cage that are not blocked by the valve body, and the fluid characteristics are controlled between the seat surface of the valve body and the seat surface of the valve seat. It is discharged to the outlet flow path side through a constriction section formed in the flow path.

At this time, in the present invention, the fluid is smoothly discharged in a fixed direction due to the guiding action of the small holes in the cage, and the fluid is discharged with a reduced flow velocity due to the loss action, so that the fluid is not caused by severe cavitation vibration. A very short-period cavity growth phenomenon does not occur.

According to the present invention as set forth in claim 1, there are the following effects.

■Each columnar plate that makes up the cage is arranged vertically along the direction of movement of the valve body, so there is no stickiness that obstructs the opening and closing movement of the valve body, which is the case with conventional disc stacked cages. This ensures smooth opening and closing operations.

■Related to the above (■), the closing operation of the valve body becomes smooth without any resistance, and a reliable closing state without leakage is ensured when the valve is fully closed.

(2) Since the small hole in the cage exists at any position in the axial direction of the cage (the opening/closing direction of the valve body), the flow rate characteristics with respect to changes in the opening degree of the valve body are continuous. Therefore, when controlling the movement of the valve body for flow rate control, no hunting phenomenon occurs and stable flow rate control can be ensured.

Further, according to the second aspect of the present invention, it is possible to obtain a guiding effect of bending the direction of the fluid flowing out from the small hole of the cage from horizontal to downward. Therefore, a smooth flow of fluid toward the outlet channel can be formed, and vibrations occurring in various parts of the valve can be suppressed. In addition, when using a conventional disc-stacked cage, the small holes formed between the discs are provided substantially horizontally, and cannot be set in a downwardly inclined shape as described above.

Further, according to the present invention as set forth in claim 3, it is possible to enhance the loss effect due to the small holes of the cage.

[Embodiment] Fig. 1 is a sectional view showing a high differential pressure regulating valve according to an embodiment of the present invention, Fig. 2 is a schematic diagram showing the main parts of Fig. 1, and Fig. 3 shows a cage. A schematic diagram, FIG. 4 is a schematic diagram showing a columnar plate, FIG. 5 is a schematic diagram showing the arrangement of small holes formed by the columnar plate, FIG. 6 is a schematic diagram showing a modification of the columnar plate, and FIG. FIG. 3 is a schematic diagram showing another modification of the columnar plate.

The high differential pressure regulating valve 10 has a casing 14 including an inlet passage 11, an outlet passage 12, and a valve chamber 13. The casing 14 includes a child valve body guide 15 and a child valve body kite 1.
6 are fixedly arranged.

The child valve body guide 16 includes a valve seat 17 that communicates the inlet channel 11 and the outlet canal 12 .

The child valve body kite 15 and the child valve body guide 16 slidably support a valve body 19 that is integral with the valve stem 18 .

The valve body 19 is provided opposite to the valve seat 17, moves upward from the valve seat 17, and aligns the seat surface 20 provided on the valve body 19 with respect to the seat surface 17A provided on the valve seat 17. It is designed so that it can be brought into contact with and separated from it.

As shown in FIG. 2, a cage 21 is attached to a portion of the child valve body guide 16 that slidably supports the valve body 19. As shown in FIG. 22 is a cage fixing ring screwed onto the upper end of the child valve body guide 16.

A large number of small holes 23 and 24 are provided in each of the child valve body guide 16 and the cage 21.

The small hole 24 of the cage 21 is opened and closed by the valve body 19.
In the open state, it flows from the inlet flow path 11 into the annular flow path 25, and further passes through the small hole 23 of the child valve body guide 16 to the valve body 19.
control the fluid streamlines that flow around it.

Further, the lower part of the seat surface 20 of the valve body 19 has a concave shape and a diameter reduced toward the valve center axis side from the seat surface 20 and protrudes downward, so that the fluid flowing out from the small hole 24 is connected to the outlet. A rectifying surface 26 is formed to smoothly guide the flow path 12 toward the outlet side.

As shown in FIGS. 2 and 3, the cage 21 is formed by arranging a large number of columnar plates 27 having fan-shaped cross sections in a ring shape. As shown in FIGS. 4 and 5, a groove-like channel portion 28 is provided on the side surface of each columnar plate 27, thereby forming the small hole 24. Further, the cage 21 is configured such that the small holes 24 are present at any position in the axial direction of the cage 21 by setting the position of the flow passage portion 28 in the lower columnar plate 27.

Furthermore, the flow path portion 2 provided on the side surface of each columnar plate 27
8 is given a downward inclination angle θ so as to guide the fluid toward the outlet channel 12, as shown in FIG.

Incidentally, the inclination angle θ of the flow path portion 28 is set to be smaller for the flow path portion 28 located on the lower end side closer to the valve seat 17. For example, in FIG. 4, the lowest flow path section 28 is θ
1=30 degrees, and the flow path portion 28 above it is set to θ2=32.5 degrees. The reason for this is to prevent the fluid ejected from the small hole 24 from hitting the seat surface 17A of the valve seat 17,
The purpose is to prevent damage to the seat surface 17A.

Next, the operation of the above embodiment will be explained.

In the above embodiment, the fluid flowing into the casing 14 flows through the small hole 2 of the cage 21 that is not blocked by the valve body 19.
4, the fluid streamline is controlled, and the seat surface 2 of the valve body 19
0 passes through a constriction formed between the valve seat 17 and the seat surface 17A, and is discharged to the outlet flow path 12 side.

At this time, in the above embodiment, the small hole 24 of the cage 21
The fluid is smoothly discharged in a constant downward direction due to the guiding action of the fluid, and the flow velocity is reduced due to the loss action, so that the very short-period cavity growth phenomenon that causes severe cavitation vibrations does not occur. do not have.

According to the above embodiment, there are the following effects.

■Each columnar plate 27 or valve body 19 that constitutes the cage 21
Since the valve element 19 is arranged vertically in the direction of movement of the valve element 19, there is no stickiness that obstructs the opening/closing movement of the valve element 19 as in conventional disc stacked cages, and smooth opening/closing operation of the valve element 19 can be ensured. .

(2) In relation to (2) above, the closing operation of the valve body 19 becomes smooth without any resistance, and a reliable closing state without leakage is ensured when the valve is fully closed.

■Since the small hole 24 of the cage 21 exists at any position in the axial direction of the cage 21 (the opening/closing direction of the valve body 19), the flow rate characteristics with respect to changes in the opening degree of the valve body 19 become continuous. . Therefore, when controlling the movement of the valve body 19 for flow rate control, stable flow rate control can be ensured without causing the hunting phenomenon.

In particular, in this embodiment, the position and shape of the small hole 24 are set so that the rate of increase in the fluid passage area remains constant regardless of the opening degree of the valve body 19. The flow characteristics will be obtained.

Note that the cage 21 may have a plurality of small holes that overlap each other at the same position in the axial direction.

(2) A guiding action that bends the direction of the fluid flowing out from the small holes 24 of the cage 21 from horizontal to downward can be obtained. Therefore, the fluid can form a smooth flow toward the outlet flow path 12, and vibrations occurring in various parts of the valve can be suppressed.

The columnar plate 100 shown in FIG. 6 is an example in which the groove-like flow path portion 101 provided on the side surface thereof is provided with irregularities that cause resistance loss to the fluid. When a cage is constituted by this columnar plate 100, the flow path of the small holes is made to be winding, which can increase the loss effect due to the small holes.

Incidentally, the loss effect due to the small holes can be adjusted by changing the number of bends in the flow path to change the flow direction, and an arbitrary degree of loss can be provided.

Figure 7 shows a set of three columnar plates 201.202.2.
03 constitutes a cage, and two columnar plates 201
．． 202 is provided with a plurality of windows 204, and the combination of these windows 204 forms a small hole with a winding flow path.

In carrying out the present invention, the structure supported by the cage casing is not limited to that of the above embodiment.

[Effects of the Invention] As described above, according to the present invention, when cavitation vibration is reduced using a cage equipped with small holes that control fluid flow lines flowing around the valve body, smooth opening and closing operations of the valve body can be achieved. It is possible to ensure a reliable shut-off state and stable flow control.

204...window part (Flow path)

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a high differential pressure regulating valve according to an embodiment of the present invention, FIG. 2 is a schematic diagram showing the main parts of FIG. 1, and FIG. 3 is a schematic diagram showing a cage. Fig. 4 is a schematic diagram showing a columnar plate, Fig. 5 is a schematic diagram showing the arrangement of small holes formed by the columnar plate, Fig. 6 is a schematic diagram showing a modification of the columnar plate, and Fig. 7 is a schematic diagram showing a modification of the columnar plate. It is a schematic diagram which shows another modification. DESCRIPTION OF SYMBOLS 10... High differential pressure control valve, 14... Casing, 17... Valve seat, 17A... Seat surface, 19... Valve body, 20... Seat surface, 21... Cage, 24... Small hole, 27.100.201.202.203... Columnar plate, 28.101... Channel portion,

Claims (3)

[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; It has a movable valve body and a cage that is coaxially provided around the valve body while being supported by a casing and has a small hole formed therein for controlling fluid flow lines flowing around the valve body. In a high differential pressure regulating valve in which the seat surface provided on the valve body is brought into contact with and separated from the seat surface provided on the valve seat, a large number of columnar plates each having a fan-shaped cross section are arranged to form an annular shape. By arranging them side by side, the cage is formed, and the small hole of the cage is formed by the passage section provided on the side surface of each columnar plate, and the axial direction of the cage is formed by setting the position of the passage section on each columnar plate. A high differential pressure regulating valve characterized in that a small hole is present at any position. (2) The high differential pressure regulating valve according to claim 1, wherein the flow path section provided on the side surface of the columnar plate is inclined downward so as to guide the fluid toward the outlet flow path side. (3) The high differential pressure regulating valve according to claim 1, wherein the flow path portion provided on the side surface of the columnar plate is provided with irregularities that cause fluid loss.