JPWO2007046379A1 - Cage valve - Google Patents

Abstract

A cage 7 that is fixed in one chamber divided by a partition wall 2 that divides the valve body into an upstream side and a downstream side and that has a plurality of flow control windows 13 on the peripheral wall, and that slides inside the cage 7 In the cage valve provided with the valve plug 15 for opening and closing the flow control window 13 of FIG. 7, a low opening flow rate characteristic part 31 having a gap with the inner wall of the cage is provided on the lower peripheral surface of the cage 7, and has a simple structure, and Provided is a small cage valve with excellent high rangeability that can be used in a wide range of flow rates from small to large flow rates.

Description

  The present invention relates to a cage valve including a cage having a flow control window on a peripheral wall and a valve plug that moves up and down in the cage to control the flow rate of the fluid by controlling the opening area of the flow control window.

  The flow rate of the cage valve is adjusted by changing the opening area of a plurality of flow rate control windows provided on the cage peripheral wall. As a mechanism for changing this flow control window, a cylindrical or circular pipe-shaped valve plug is mounted inside the cage, and the valve plug is reciprocated up and down by an operating device, etc., so that the valve plug opens the area of the flow control window. A method of changing the value is generally used.

  In a cage valve having such a mechanism, when the fluid pressure is significantly reduced or when the flow velocity is high, abnormally high noise may be generated due to turbulence in the throttle portion of the valve, or cavitation may occur. In some cases, the performance and durability of the valve may be significantly reduced. Moreover, there is a possibility that damage, vibration, noise, and cavitation of the valve may be caused by the liquid that vigorously flows out from the lower outlet of the cage valve colliding with the inner bottom surface of the valve on the downstream side of the valve.

In order to solve such problems, proposals have been made for providing pressure equalizing grooves in the plug and cage, attaching a piston ring for preventing gap flow, and attaching a divider under the plug.
However, these measures are measures at an intermediate opening, and the effect is small for vibration at a low opening (about 0 to 15%). Until now, the normal use range of cage valves has been used from the middle opening degree in many cases, and the problem at a low opening degree has not been a serious problem in practice.
In recent years, the specifications of cage valves have also tended to increase in demands such as low noise, cavitation resistance, high differential pressure specifications, large diameters, use of corrosion-resistant materials, high rangeability, low seat leakage, and extremely low temperatures. There is an urgent need to take effective measures for controllability at a certain degree.
There are the following as prior art documents aiming at improving the controllability of such a cage valve at a low opening.

Japanese Patent Publication No.7-3263

FIG. 11 shows a cross-sectional view of the main part of the cage valve disclosed in Patent Document 1. The cross-sectional view shown in FIG. 11 shows a low opening state. A casing 103 including an inlet channel 101 and an outlet channel 102; a cage 105 including ports 104 and 114 provided between the inlet channel 101 and the outlet channel 102 in the casing 103; A plurality of disk portions 106, 116 that can move with respect to the casing 103 and the cage 105, open and close the ports 104, 114 of the cage 105, and a valve rod 107 connected to the plurality of disk portions 106, 116. Yes.
Then, by opening and closing the valve rod 107, the plurality of disk portions 106 and 116 increase or decrease the fluid passage area of each port 104 and 114 so that the fluid on the inlet channel side can be continuously decompressed.
The high resistance flow path 120 that flows upward along the valve rod 107 flows through a plurality of stages of high resistance flow path ports 114. Further, the low resistance flow path 121 flowing below the valve rod 107 flows through the low resistance flow path port 104 having a smaller number of stages than the high resistance flow path port 114.
11 shows a low opening state, the low resistance channel port 104 is in a closed state, and the low resistance channel 121 is not formed.
By adopting the above configuration, the fluid on the inlet channel side is guided to the high resistance channel side in the low opening region, and is guided to the low resistance channel side together with the high resistance channel side in the middle and high opening regions. Yes.

  In the conventional valve device described in Patent Document 1, a valve body and a valve mechanism (cage, plug, etc.) are provided in order to provide two channels of a high resistance channel 120 and a low resistance channel 121 in the valve body. There is a problem that the valve body becomes large as it becomes complicated.

  The present invention has been made paying attention to the above circumstances, and the object is to have a simple structure and a small size excellent in high range ability that can be used in a wide range of flow rates from a small flow rate to a large flow rate. It is to provide a cage valve.

  The cage valve according to the present invention includes a cage that is fixed in one chamber divided by a partition wall that divides the inside of the valve body into an upstream side and a downstream side, and that has a plurality of windows on a peripheral wall, and slides in the cage. And a valve plug that opens and closes the window of the cage, and a low opening flow rate characteristic portion having a gap with the inner wall of the cage is provided on the peripheral surface of the lower end of the valve plug.

  In the cage valve according to the present invention, the gap between the low opening flow rate characteristic portion on the lower peripheral surface of the plug and the cage inner wall becomes wider as the opening increases within the range of the low opening, and the plug peripheral surface A seat portion is provided at the upper end of the low opening flow rate characteristic portion.

The cage valve according to the present invention includes a cage that is fixed in one chamber divided by a partition wall that divides the inside of the valve body into an upstream side and a downstream side, and that has a plurality of windows on a peripheral wall, and slides in the cage. In a cage valve comprising a cylindrical valve plug that opens and closes the cage window,
A low opening flow rate characteristic portion that communicates the outer surface and the inner surface of the valve plug is provided on the lower end peripheral surface of the valve plug, and a seat portion is provided at the upper end of the low opening flow rate characteristic portion of the valve plug peripheral surface. It is.

  According to the present invention, at a low opening, the fluid flows through the gap between the cage inner wall and the low opening flow rate characteristic portion of the peripheral surface of the lower end of the plug. It is possible to improve the controllability of the low flow rate at the time. In addition, since the control at a low opening is stabilized, vibration is reduced, reliability is improved, low stress design is possible, and a long life is achieved.

  According to this invention, since the seat portion is provided at the upper end of the low opening flow rate characteristic portion of the plug peripheral surface, the seal when fully closed can be ensured. Further, by processing the lower end of the valve plug, the low opening flow rate characteristic portion can be provided with a simple configuration.

  According to this invention, since the seat portion is provided at the upper end of the low opening flow rate characteristic portion of the plug peripheral surface, the seal when fully closed can be ensured. Moreover, by providing the low opening flow rate characteristic part which connects the valve plug outer surface and the inner surface at the lower end of the valve plug, the low opening flow rate characteristic part can be provided with a simple configuration.

Embodiment 1 FIG.
FIG. 1 is a longitudinal sectional view of an essential part showing a state in which the valve device according to the first embodiment is almost fully opened. FIG. 2- (1) is a cross-sectional view of the plug of the valve device and an enlarged view of the portion A, and FIG. 2- (2) is a cross-sectional view of the plug of the valve device as a comparative example and an enlarged view of the B portion. . FIGS. 3A and 3B are diagrams showing the dimensions of the plug. FIG. 4- (1) is a diagram showing a cross-sectional view of the plug and cage in a state where the opening degree is 5%. FIG. 4- (2) is an enlarged view of part E in FIG. 4- (1). FIG. 5- (1) is a cross-sectional view of the plug and cage in a state where the opening degree is 0%, FIG. 5- (2) is a cross-sectional view of the plug and cage in a state where the opening degree is 10%, and an enlarged view of part C. -(3) is a cross-sectional view of the plug and cage in a state of 100% opening. FIG. 6 is a flow characteristic curve up to 0 to 100% opening of the comparative example and the first embodiment. FIG. 7 is a flow characteristic curve up to 0 to 14% opening of the comparative example and the first embodiment.

  In FIG. 1, the valve body 1 is partitioned into an upstream flow path 3 and a downstream flow path 4 by a partition wall 2 that is a partition wall. A cylindrical cage 7 is provided between the upper lid 5 that closes the upper end opening 29 of the valve body 1 and the partition wall 2. The upper lid 5 is fixed to the valve body 1 with bolts 27. Although not shown, a gasket is fitted between the upper lid 5 and the cage 7, and a gasket is fitted between the cage 7 and the valve body 1.

The cage 7 is provided so as to be divided into an upper cage 7a and a lower cage portion 7b. In addition, a spiral is provided in the hole provided in the upper outer periphery of the lower cage portion 7b and the partition wall 2, and the lower cage portion 7b is detachably screwed to the partition wall 2.
The lower cage portion 7b and the upper cage portion 7a are fixed so as not to rotate by engaging the fitting groove 34 provided in the lower cage portion 7b and the protrusion 35 provided in the upper cage portion 7a.
Further, in the first embodiment, the upper cage portion 7a can be further divided into two parts in the vertical direction, and the projection 37 provided on the upper portion of the upper cage portion 7a and the fitting groove 36 provided on the lower portion are engaged with each other to rotate. It is impossible to fix.

The cage 7 is fitted into a through hole formed in the center of the partition wall 2 via a gasket 10 and is fixed between the upper end opening 29 of the valve body 1 and the partition wall 2.
A plurality of circular flow rate control windows 13 are provided in the peripheral wall of the upper cage portion 7a to connect the downstream flow path 4 and the inside of the cage. In addition, a plurality of circular openings 33 are provided in the peripheral wall and the lower portion of the lower cage portion 7b to communicate the upstream flow path 3 and the cage interior.

  A valve plug 15 is slidably fitted into the cage upper portion 7a along the inner peripheral wall surface thereof. And the valve seat 14 located under the flow control window 13 is formed in the inner peripheral wall surface of the lower cage part 7b. A seat surface 19 is provided on the valve plug 15, and the seat surface 19 faces the valve seat 14. The valve stem 5 is fixed so as to be movable in the vertical direction with respect to the valve main body 1 via a packing or the like (not shown). The valve plug 15 and the valve stem 18 are integrated by means such as welding. The main body 1 is movable in the vertical direction.

As shown in FIG. 2-(1), the valve plug 15 is provided with a low opening flow rate characteristic portion 31 for providing a gap with the inner wall of the cage on the lower peripheral surface of the cage 7.
A seat surface 19 is provided at the upper end of the low opening flow rate characteristic portion 31 on the peripheral surface of the valve plug 15 via a straight portion 39 having a slight length, and the low opening flow rate characteristic on the lower peripheral surface of the valve plug 15 is provided. The low opening flow rate characteristic portion 31 is in relation to the outer peripheral surface of the valve plug 15 that slides with the cage 7 so that the gap between the portion 31 and the inner wall of the cage becomes wider as the opening increases within the range of the low opening. It is formed at a very small angle.
That is, the outer peripheral surface of the low opening flow rate characteristic unit 31 is set so that the outer peripheral diameter of the uppermost end portion of the low opening degree flow characteristic unit 31 is slightly larger than the outer peripheral diameter of the lower end flow rate characteristic unit 31. Is not parallel to the contact surface between the valve plug 15 and the cage 7, but is provided at a slight angle.
The straight portion 39 is provided to ensure the dimensional stability of the low opening flow rate characteristic unit 31 and is not necessarily required. The upper end of the low opening flow rate characteristic unit 31 is not necessarily provided via the straight portion 39. A sheet surface 19 may be provided.

FIG. 3 shows an example of the dimensions of the plug according to the first embodiment.
The outer diameter of the outer peripheral surface of the valve plug 15 sliding with the cage 7 is 267 mm, whereas the outer diameter of the lowermost end of the low opening flow rate characteristic portion 31 is 260.5 mm, and the outermost diameter of the low opening flow rate characteristic portion 31 is The outer peripheral diameter of the upper end is 264 mm. The low opening flow rate characteristic part 31 is for flowing a very small amount of fluid at a low opening degree, and the gap between the inner peripheral surface of the cage 7 and the low opening flow rate characteristic part 31 of the valve plug 15 is at most a valve. The length of the plug 15 is on the order of several percent. As a result, the fluid is doubled in the clearance gap between the valve plug 15 and the inner peripheral surface of the cage 7 and the narrowest gap between the inner peripheral surface of the cage 7 and the low opening flow rate characteristic portion 31 of the valve plug 15. Will be. More preferably, as shown in FIGS. 4 (1) and (2), the narrowest gap a between the inner peripheral surface of the cage 7 and the low opening flow rate characteristic portion 31 of the valve plug 15 when the opening degree is around 5%. The flow path area at −a is designed to be equal to or less than the clearance gap b−b between the valve plug 15 and the inner peripheral surface of the cage 7. If designed in this way, a high Rb (ratio Cvmax / Cvmin between the adjustable maximum flow rate Cvmax and the minimum flow rate Cvmin) can be realized in the low opening flow rate characteristic unit 31, and therefore the flow rate control window 13 at the lowest end of the cage 7. Can be disposed in the vicinity of the seat portion of the cage, and it is possible to greatly prevent a gap flow from being generated just before the clearance between the cage inner peripheral surface 7 and the valve plug 15 at a low opening, and generation of vibrations caused by this gap flow Can be greatly reduced.
Further, the length from the seat surface 19 of the valve plug 15 to the lower end of the low opening flow rate characteristic portion 31 is preferably about 20% of the distance that the valve plug 15 moves from the maximum opening to the minimum opening. .
As a result, high rangeability can be realized, and both improvement in controllability at a low opening and securing of a Cv value at a high opening can be achieved.
The straight portion 39 may have a length of about 1 to 2 mm between the upper end of the low opening flow rate characteristic portion 31 of the valve plug 15 and the seat surface 19.
However, these specific dimensions are merely examples, and are appropriately set according to the maximum flow rate, differential pressure, fluid type, and the like.

Next, the operation will be described. 5- (1) is a cross-sectional view of the plug and cage in the state of 0% opening, FIG. 5- (2) is a cross-sectional view of the plug and cage in the state of low opening, and an enlarged view of part C, FIG. (3) shows a cross-sectional view of the plug and cage in a state where the opening degree is 100%.
When the valve shaft 18 is operated upward by an operation unit (not shown) or manually from the state of 0% opening in FIG. 5-(1), the flow control window 13 is closed by the valve plug 15, and the seat surface of the valve plug 15 The valve plug 15 gradually moves upward from a state in which 19 is seated on the valve seat 14 and is in close contact therewith.

  Then, the flow control window 13 and the low opening flow rate characteristic unit 31 are gradually communicated, and the flow control window 13 that has been closed by the valve plug 15 is opened. FIG. 5- (2) shows a low opening state when the flow control window 13 and the low opening flow rate characteristic unit 31 communicate with each other. As shown in the enlarged view C of FIG. 5-2, only the flow control window 13 at the lowermost end communicates with the low opening flow rate characteristic unit 31, and between the low opening flow rate characteristic unit 31 and the inner wall of the cage 7. The fluid flows from the upstream flow path 3 to the downstream flow path 4 in a state where the flow resistance is large through the formed very thin flow path.

When the valve plug 15 is further operated upward, more flow rate control windows 13 are opened, and a flow path is established through which a fluid can flow without going through the low opening flow rate characteristic unit 31. The resistance becomes smaller and a large flow rate flows. Eventually, when the 100% opening shown in FIG. 5- (3) is reached, the majority of the flow control windows 13 are opened.
FIG. 6 shows flow rate characteristic curves from 0 to 100% of the comparative example and the first embodiment. Moreover, FIG. 7 shows the flow rate characteristic curve to 0-14% opening degree of a comparative example and Embodiment 1. FIG.

Here, the valve device of the comparative example will be described. FIG. 2- (2) shows a sectional view and an enlarged view of a plug of a valve device as a comparative example.
The difference from the valve device of the first embodiment described above is only the shape of the valve plug. The valve plug 115 of the comparative example does not have the low opening flow rate characteristic portion 31 of the first embodiment, and the seat surface 119. Is provided at the lowermost end of the valve plug. Other parts such as the valve stem 18 and the cage 7 are all provided in the same manner as in the first embodiment.

  The operation of the valve device of the comparative example will be described. When the seat surface 119 of the valve plug 115 and the valve seat 14 of the cage 7 are separated from each other and the flow control window 13 at the lowermost end is opened, the valve device of the first embodiment is used. Since no low opening flow rate characteristic unit 31 is provided, the flow rate increases rapidly in the low opening range as compared with the valve device of the first embodiment. When the opening degree is further increased and a high opening degree region is reached, the relationship between the operation amount of the valve plugs 15 and 115 and the increase amount of the flow rate does not change much between the valve device of the first embodiment and the valve device of the comparative example.

For the reasons described above, as shown in FIGS. 6 and 7, the gradients of the valve device of the first embodiment and the valve device of the comparative example are substantially the same in the high opening region. In the low opening region, the flow rate does not increase at a stretch even when the valve device of the first embodiment is the same operation amount as the valve device of the comparative example. In the first embodiment, at a low opening, the fluid flows through a gap between the cage inner wall and the low opening flow rate characteristic portion 31 on the peripheral surface of the lower end of the plug. The controllability of the low flow rate at the time of opening can be improved.
In addition, since the control at a low opening is stabilized and vibration is reduced, reliability is improved, and low stress design can be performed by reducing the vibration. Furthermore, the lifetime can be extended.
In particular, according to the first embodiment, as shown in FIG. 7, a remarkable effect can be obtained in the flow characteristic at the beginning of opening where the opening degree is about 0% to 14%.
In the first embodiment, an example in which the flow control window 13 and the opening 33 are circular has been shown, but the shape of the flow control window 13 and the opening 33 is not limited to a circle, and may be an ellipse, a rectangle, or the like. .
Moreover, although the example which provides the cage 7 in three divisions was shown, it may be provided so that it cannot be divided, or may be provided so as to be further divided into a plurality.
Moreover, although the example in which the cage 7 and the valve body 1 are screwed is shown, the cage 7 may be fixed to the valve body by other fixing means without being screwed.
In addition, an example in which the shape of the contact cross section between the inner wall of the cage 7 and the outer periphery of the valve plug 15 that slides is shown as a circle. May be another shape, such as an ellipse.
Moreover, although the example which flows toward the upper direction from the downward direction of the valve plug 15 was shown about the flow direction, you may set a reverse flow, ie, a flow direction so that it may flow toward the downward direction from the upper direction of the valve plug 15. .

Embodiment 2. FIG.
FIG. 8 (1) is a cross-sectional view of the plug of the valve device according to the second embodiment of the present application, FIG. 8 (2) is an enlarged view of portion E of FIG. 8 (1), and FIG. 8 (3) is FIG. The figure which looked at from the downward direction is shown.
The difference from the valve device of the first embodiment described above is only the shape of the valve plug, and the low opening flow rate characteristic unit 332 of the valve plug 315 of the second embodiment and the low opening flow rate characteristic unit of the first embodiment. The other parts such as the valve stem 18 and the cage 7 are provided in the same manner as the valve device of the first embodiment, although the shape is different from that of the valve 31.

As shown in FIGS. 8 (1), (2), and (3), the low opening flow rate characteristic portion 332 of the valve device of the second embodiment is provided at the lower end portion of the valve plug 315 and below the seat surface 319. ing.
Although the outer diameter of the valve plug 315 below the seat surface 319 is smaller than the diameter in contact with the outer periphery of the cage, it has a substantially constant value and is not formed with a gradient as in the first embodiment, and is parallel to the valve shaft 318. It is straight. And the notch part is provided in the substantially triangular shape in the position corresponding to the location where the flow control window 13 of the cage 7 is provided, and the low opening flow rate characteristic part 332 is formed. The notch which is the low opening flow rate characteristic portion 332 penetrates from the outer peripheral surface of the valve plug 315 to the inner peripheral surface.

  Next, the operation will be described. When the valve shaft 318 is operated upward by an operation unit (not shown) or manually from the state where the opening degree is 0%, the flow control window 13 is closed by the valve plug 315 and the seat surface 319 of the valve plug is seated on the valve seat 14. The valve plug 315 gradually moves upward from the close contact state.

Then, the flow control window 13 and the low opening flow rate characteristic portion 332 are gradually communicated, and the flow control window 13 closed by the valve plug 315 is opened. According to the second embodiment, the notch is provided in a substantially triangular shape at a position corresponding to the location where the flow control window 13 of the cage 7 is provided. Therefore, at the low opening, the apex of the substantially triangular cutout portion, which is the low opening flow rate characteristic portion 332, communicates with the flow control window 13 first, so that the flow rate does not increase rapidly, and the inside of the lower end of the plug By connecting the peripheral surface and the outer peripheral surface, it is possible to improve the controllability of the low flow rate at the time of the low opening without involving a complicated configuration and an increase in size. Similar to the first embodiment, according to the second embodiment, as shown in FIG. 7, a remarkable effect can be obtained in the flow characteristic at the beginning of opening where the opening degree is about 0% to 14%.
In the second embodiment, an example in which the shape of the notch is approximately triangular has been shown. However, the shape of the notch is substantially rectangular, semicircular, trapezoidal, etc., and the flow rate increases rapidly at a low opening. Instead, it is possible to adopt a shape that allows the inner peripheral surface and the outer peripheral surface of the lower end of the valve plug 315 to communicate with each other.

Embodiment 3 FIG.
9 (1) is a cross-sectional view of the plug of the valve device according to the third embodiment of the present invention, FIG. 9 (2) is an enlarged view of a portion F in FIG. 9 (1), and FIG. 9 (3) is FIG. 9 (1). FIG. 9 (4) shows a side view of the plug according to the third embodiment.
The difference from the valve device of the first embodiment described above is only the shape of the valve plug, and the low opening flow rate characteristic unit 432 of the valve plug 415 of the third embodiment and the low opening flow rate characteristic unit of the first embodiment. Although the shape of the valve 31 is different from that of the valve 31, all other parts such as the valve rod 18 and the cage 7 are provided in the same manner as the valve device of the first embodiment.

As shown in FIGS. 9 (1), (2), (3), and (4), the low opening flow rate characteristic portion 432 of the valve device of the third embodiment has a lower end portion of the valve plug 415 and a seat surface 419. It is provided below.
Although the outer diameter of the valve plug 415 below the seat surface 419 is smaller than the diameter in contact with the outer periphery of the cage, it is a substantially constant value and is not formed with a gradient as in the first embodiment, and is parallel to the valve shaft 418. It is straight. A notch portion is provided in a substantially rectangular shape at a position corresponding to the location where the flow rate control window 13 of the cage 7 is provided, and a low opening flow rate characteristic portion 432 is formed. The notch portion which is the low opening flow rate characteristic portion 432 is not penetrated to the inner peripheral surface of the valve plug 415 and is provided so that the depth of the notch portion becomes deeper toward the lower end of the valve plug 415. ing.

  Next, the operation will be described. When the valve shaft 418 is operated upward from the 0% opening degree by an operating unit (not shown) or manually, the flow control window 13 is closed by the valve plug 415 and the seat surface 419 of the valve plug is seated on the valve seat 14. The valve plug 415 gradually moves upward from the close contact state.

  Then, the flow control window 13 and the low opening flow rate characteristic unit 432 are gradually communicated, and the flow control window 13 closed by the valve plug 415 is opened. According to the third embodiment, the notch portion which is the low opening flow rate characteristic portion 432 does not penetrate to the inner peripheral surface of the valve plug 415, and the depth of the notch portion becomes closer to the lower end of the valve plug 415. It is provided to be deep. Therefore, since the portion where the depth of the upper end portion of the notch portion is shallow is initially communicated with the flow control window 13 at the low opening, the flow rate characteristic portion at the lower end of the plug does not increase rapidly. By flowing through the gap between 332 and the inner wall surface of the cage 7, it is possible to improve the controllability of the low flow rate at the time of low opening without complicated structure and large size. Similar to the first embodiment, according to the third embodiment, as shown in FIG. 7, a remarkable effect can be obtained in the flow characteristic at the beginning of opening where the opening degree is about 0% to 14%.

Embodiment 4 FIG.
10 (1) is a cross-sectional view of the plug of the valve device according to the fourth embodiment of the present invention, FIG. 10 (2) is an enlarged view of a portion G in FIG. 10 (1), and FIG. 10 (3) is FIG. FIG. 10 (4) shows a side view of the plug according to the fourth embodiment.
The difference from the valve device of the first embodiment described above is only the shape of the valve plug, and the low opening flow rate characteristic unit 532 of the valve plug 515 of the fourth embodiment and the low opening flow rate characteristic unit of the first embodiment. Although the shape of the valve 31 is different from that of the valve 31, all other parts such as the valve rod 18 and the cage 7 are provided in the same manner as the valve device of the first embodiment.

As shown in FIGS. 10 (1), (2), (3), and (4), the low opening flow rate characteristic portion 532 of the valve device of the fourth embodiment has a lower end portion of the valve plug 515 and a seat surface 519. It is provided below.
Although the outer diameter of the valve plug 515 below the seat surface 519 is smaller than the diameter in contact with the outer periphery of the cage, it is a substantially constant value and has no gradient as in the first embodiment, and is parallel to the valve shaft 518. It is straight. And the notch part is provided in the substantially triangular shape in the position corresponding to the location where the flow control window 13 of the cage 7 is provided, and the low opening flow rate characteristic part 532 is formed. The notch portion which is the low opening flow rate characteristic portion 532 is not penetrated to the inner peripheral surface of the valve plug 515 and is provided so that the depth of the notch portion becomes longer toward the lower end of the valve plug 515. ing.

  Next, the operation will be described. When the valve shaft 518 is operated upward from an open state of 0% by an operating unit (not shown) or manually, the flow control window 13 is closed by the valve plug 515 and the seat surface 519 of the valve plug is seated on the valve seat 14. The valve plug 515 gradually moves upward from the close contact state.

Then, the flow rate control window 13 and the low opening flow rate characteristic unit 532 are gradually communicated, and the flow rate control window 13 closed by the valve plug 515 is opened. According to the fourth embodiment, a notch that is provided with a notch in a substantially triangular shape at a position corresponding to the location where the flow control window 13 of the cage 7 is provided and that is the low opening flow rate characteristic unit 532. The portion is not penetrated to the inner peripheral surface of the valve plug 415, and is provided such that the depth of the notch becomes longer toward the lower end of the valve plug 415. Therefore, at a low opening, since it is first communicated with the flow rate control window 13 from the portion of the approximately triangular apex of the notch that is shallow in depth, it is more drastically compared to the second and third embodiments. By flowing through the gap between the low opening flow rate characteristic portion 532 at the lower end of the plug and the inner peripheral surface of the cage 7 without increasing the flow rate, the low flow at the low opening degree is not accompanied by a complicated configuration and an increase in size. The controllability of the flow rate can be improved. As in the first embodiment, according to the fourth embodiment, as shown in FIG. 7, a remarkable effect can be obtained in the flow characteristic at the beginning of opening where the opening degree is about 0% to 14%.
In Embodiments 3 and 4, an example in which the shape of the notch is approximately triangular or approximately rectangular has been shown. However, the shape of the notch is semicircular, trapezoidal, etc., and the flow rate increases rapidly at a low opening. Instead, it is possible to adopt a shape that can flow the gap between the low opening flow rate characteristic portions 432 and 532 at the lower end of the plug and the outer peripheral surface of the plug.

  As described above, the cage valve according to the present invention is suitable for use in a valve that controls a wide flow rate from a small flow rate to a large flow rate.

It is a principal part longitudinal cross-sectional view which shows the state by which the valve apparatus by Embodiment 1 of this invention is substantially fully open. It is sectional drawing of the plug of Embodiment 1 of this invention, and the enlarged view of A part. It is sectional drawing of the plug of the valve apparatus which is a comparative example of this invention, and the enlarged view of B part. It is a figure which shows the dimension of the plug of Embodiment 1 of this invention. FIG. 4- (1) is a diagram showing a cross-sectional view of the plug and cage in the state of opening 5% in the first embodiment of the present invention. FIG. 4- (2) is an enlarged view of part E of FIG. 4- (1). It is a figure which shows sectional drawing of the plug and cage of the state of opening degree 0% in Embodiment 1 of this invention. It is a figure which shows the sectional view of a plug and a cage in the state of 10% of opening degree in Embodiment 1 of this invention, and the enlarged view of C part. It is a figure which shows sectional drawing of the plug and cage of the state of 100% of opening degree in Embodiment 1 of this invention. It is a flow characteristic curve to 0-100% opening degree of the comparative example and Embodiment 1 of this invention. It is a flow characteristic curve to 0-14% opening degree of the comparative example and Embodiment 1 of this invention. FIG. 8- (1) is a cross-sectional view of the plug of the valve device according to the second embodiment of the present application, FIG. 8- (2) is an enlarged view of portion E in FIG. 8- (1), and FIG. It is the figure which looked at 8- (1) from the downward direction. 9- (1) is a cross-sectional view of the plug of the valve device according to the third embodiment of the present invention, FIG. 9- (2) is an enlarged view of a portion F in FIG. 9- (1), and FIG. FIG. 9- (1) is a view from below, and FIG. 9- (4) is a side view of the plug according to the third embodiment. 10- (1) is a cross-sectional view of the plug of the valve device according to the fourth embodiment of the present application, FIG. 10- (2) is an enlarged view of a portion G of FIG. 10- (1), and FIG. 10- (1) is a view as seen from below, and FIG. 10- (4) is a side view of the plug according to the fourth embodiment. It is sectional drawing which shows the cage valve of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Valve main body 2 Partition wall 7 Cage 7A Upper cage part 7B Lower cage part 13 Flow control window 15,215,315,415,515 Valve plug 31,232,332,432,532 Low opening flow rate characteristic part

  The present invention relates to a cage valve including a cage having a flow control window on a peripheral wall and a valve plug that moves up and down in the cage to control the flow rate of the fluid by controlling the opening area of the flow control window.

  The flow rate of the cage valve is adjusted by changing the opening area of a plurality of flow rate control windows provided on the cage peripheral wall. As a mechanism for changing this flow control window, a cylindrical or circular pipe-shaped valve plug is mounted inside the cage, and the valve plug is reciprocated up and down by an operating device, etc., so that the valve plug opens the area of the flow control window. A method of changing the value is generally used.

  In a cage valve having such a mechanism, when the fluid pressure is significantly reduced or when the flow velocity is high, abnormally high noise may be generated due to turbulence in the throttle portion of the valve, or cavitation may occur. In some cases, the performance and durability of the valve may be significantly reduced. Moreover, there is a possibility that damage, vibration, noise, and cavitation of the valve may be caused by the liquid that vigorously flows out from the lower outlet of the cage valve colliding with the inner bottom surface of the valve on the downstream side of the valve.

In order to solve such problems, proposals have been made for providing pressure equalizing grooves in the plug and cage, attaching a piston ring for preventing gap flow, and attaching a divider under the plug.
However, these measures are measures at an intermediate opening, and the effect is small for vibration at a low opening (about 0 to 15%). Until now, the normal use range of cage valves has been used from the middle opening degree in many cases, and the problem at a low opening degree has not been a serious problem in practice.
In recent years, the specifications of cage valves have also tended to increase in demands such as low noise, cavitation resistance, high differential pressure specifications, large diameters, use of corrosion-resistant materials, high rangeability, low seat leakage, and extremely low temperatures. There is an urgent need to take effective measures for controllability at a certain degree.
There are the following as prior art documents aiming at improving the controllability of such a cage valve at a low opening.

Japanese Patent Publication No.7-3263

FIG. 11 shows a cross-sectional view of the main part of the cage valve disclosed in Patent Document 1. The cross-sectional view shown in FIG. 11 shows a low opening state. A casing 103 including an inlet channel 101 and an outlet channel 102; a cage 105 including ports 104 and 114 provided between the inlet channel 101 and the outlet channel 102 in the casing 103; A plurality of disk portions 106, 116 that can move with respect to the casing 103 and the cage 105, open and close the ports 104, 114 of the cage 105, and a valve rod 107 connected to the plurality of disk portions 106, 116. Yes.
Then, by opening and closing the valve rod 107, the plurality of disk portions 106 and 116 increase or decrease the fluid passage area of each port 104 and 114 so that the fluid on the inlet channel side can be continuously decompressed.
The high resistance flow path 120 that flows upward along the valve rod 107 flows through a plurality of stages of high resistance flow path ports 114. Further, the low resistance flow path 121 flowing below the valve rod 107 flows through the low resistance flow path port 104 having a smaller number of stages than the high resistance flow path port 114.
11 shows a low opening state, the low resistance channel port 104 is in a closed state, and the low resistance channel 121 is not formed.
By adopting the above configuration, the fluid on the inlet channel side is guided to the high resistance channel side in the low opening region, and is guided to the low resistance channel side together with the high resistance channel side in the middle and high opening regions. Yes.

  In the conventional valve device described in Patent Document 1, a valve body and a valve mechanism (cage, plug, etc.) are provided in order to provide two channels of a high resistance channel 120 and a low resistance channel 121 in the valve body. There is a problem that the valve body becomes large as it becomes complicated.

  The present invention has been made paying attention to the above circumstances, and the object is to have a simple structure and a small size excellent in high range ability that can be used in a wide range of flow rates from a small flow rate to a large flow rate. It is to provide a cage valve.

  The cage valve according to the present invention includes a cage that is fixed in one chamber divided by a partition wall that divides the inside of the valve body into an upstream side and a downstream side, and that has a plurality of windows on a peripheral wall, and slides in the cage. A valve plug that opens and closes the window of the cage, and a lower opening peripheral surface of the valve plug is provided with a low opening flow rate characteristic portion having a gap with the inner wall of the cage on the lower peripheral surface of the valve plug. The gap between the low opening flow rate characteristic portion and the inner wall of the cage becomes wider as the opening increases within the low opening range, and a seat portion is provided at the upper end of the low opening flow rate characteristic portion of the valve plug peripheral surface. The length from the seat portion of the valve plug to the lower end of the low opening flow rate characteristic portion is 20% of the distance that the valve plug moves from the maximum opening to the minimum opening It is.

  According to the present invention, at a low opening, the fluid flows through the gap between the cage inner wall and the low opening flow rate characteristic portion of the peripheral surface of the lower end of the plug. It is possible to improve the controllability of the low flow rate at the time. In addition, since the control at a low opening is stabilized, vibration is reduced, reliability is improved, low stress design is possible, and a long life is achieved.

  According to this invention, since the seat portion is provided at the upper end of the low opening flow rate characteristic portion of the plug peripheral surface, the seal when fully closed can be ensured. Further, by processing the lower end of the valve plug, the low opening flow rate characteristic portion can be provided with a simple configuration.

Embodiment 1 FIG.
FIG. 1 is a longitudinal sectional view of an essential part showing a state in which the valve device according to the first embodiment is almost fully opened. FIG. 2- (1) is a cross-sectional view of the plug of the valve device and an enlarged view of the portion A, and FIG. 2- (2) is a cross-sectional view of the plug of the valve device as a comparative example and an enlarged view of the B portion. . FIGS. 3A and 3B are diagrams showing the dimensions of the plug. FIG. 4- (1) is a diagram showing a cross-sectional view of the plug and cage in a state where the opening degree is 5%. FIG. 4- (2) is an enlarged view of part E in FIG. 4- (1). FIG. 5- (1) is a cross-sectional view of the plug and cage in a state where the opening degree is 0%, FIG. 5- (2) is a cross-sectional view of the plug and cage in a state where the opening degree is 10%, and an enlarged view of part C. -(3) is a cross-sectional view of the plug and cage in a state of 100% opening. FIG. 6 is a flow characteristic curve up to 0 to 100% opening of the comparative example and the first embodiment. FIG. 7 is a flow characteristic curve up to 0 to 14% opening of the comparative example and the first embodiment.

  In FIG. 1, the valve body 1 is partitioned into an upstream flow path 3 and a downstream flow path 4 by a partition wall 2 that is a partition wall. A cylindrical cage 7 is provided between the upper lid 5 that closes the upper end opening 29 of the valve body 1 and the partition wall 2. The upper lid 5 is fixed to the valve body 1 with bolts 27. Although not shown, a gasket is fitted between the upper lid 5 and the cage 7, and a gasket is fitted between the cage 7 and the valve body 1.

The cage 7 is provided so as to be divided into an upper cage 7a and a lower cage portion 7b. In addition, a spiral is provided in the hole provided in the upper outer periphery of the lower cage portion 7b and the partition wall 2, and the lower cage portion 7b is detachably screwed to the partition wall 2.
The lower cage portion 7b and the upper cage portion 7a are fixed so as not to rotate by engaging the fitting groove 34 provided in the lower cage portion 7b and the protrusion 35 provided in the upper cage portion 7a.
Further, in the first embodiment, the upper cage portion 7a can be further divided into two parts in the vertical direction, and the projection 37 provided on the upper portion of the upper cage portion 7a and the fitting groove 36 provided on the lower portion are engaged with each other to rotate. It is impossible to fix.

The cage 7 is fitted into a through hole formed in the center of the partition wall 2 via a gasket 10 and is fixed between the upper end opening 29 of the valve body 1 and the partition wall 2.
A plurality of circular flow rate control windows 13 are provided in the peripheral wall of the upper cage portion 7a to connect the downstream flow path 4 and the inside of the cage. In addition, a plurality of circular openings 33 are provided in the peripheral wall and the lower portion of the lower cage portion 7b to communicate the upstream flow path 3 and the cage interior.

  A valve plug 15 is slidably fitted into the cage upper portion 7a along the inner peripheral wall surface thereof. And the valve seat 14 located under the flow control window 13 is formed in the inner peripheral wall surface of the lower cage part 7b. A seat surface 19 is provided on the valve plug 15, and the seat surface 19 faces the valve seat 14. The valve stem 5 is fixed so as to be movable in the vertical direction with respect to the valve main body 1 via a packing or the like (not shown). The valve plug 15 and the valve stem 18 are integrated by means such as welding. The main body 1 is movable in the vertical direction.

As shown in FIG. 2-(1), the valve plug 15 is provided with a low opening flow rate characteristic portion 31 for providing a gap with the inner wall of the cage on the lower peripheral surface of the cage 7.
A seat surface 19 is provided at the upper end of the low opening flow rate characteristic portion 31 on the peripheral surface of the valve plug 15 via a straight portion 39 having a slight length, and the low opening flow rate characteristic on the lower peripheral surface of the valve plug 15 is provided. The low opening flow rate characteristic portion 31 is in relation to the outer peripheral surface of the valve plug 15 that slides with the cage 7 so that the gap between the portion 31 and the inner wall of the cage becomes wider as the opening increases within the range of the low opening. It is formed at a very small angle.
That is, the lower end of the seat opening 19, that is, the outer periphery of the uppermost end of the low opening flow rate characteristic part 31 is slightly larger than the outer peripheral diameter of the lower end flow rate characteristic part 31. The outer peripheral surface of the opening flow rate characteristic portion 31 is not parallel to the contact surface between the valve plug 15 and the cage 7 but is provided at a slight angle.
The straight portion 39 is provided to ensure the dimensional stability of the low opening flow rate characteristic unit 31 and is not necessarily required. The upper end of the low opening flow rate characteristic unit 31 is not necessarily provided via the straight portion 39. A sheet surface 19 may be provided.

FIG. 3 shows an example of the dimensions of the plug according to the first embodiment.
The outer diameter of the outer peripheral surface of the valve plug 15 sliding with the cage 7 is 267 mm, whereas the outer diameter of the lowermost end of the low opening flow rate characteristic portion 31 is 260.5 mm, and the outermost diameter of the low opening flow rate characteristic portion 31 is The outer peripheral diameter of the upper end is 264 mm. The low opening flow rate characteristic part 31 is for flowing a very small amount of fluid at a low opening degree, and the gap between the inner peripheral surface of the cage 7 and the low opening flow rate characteristic part 31 of the valve plug 15 is at most a valve. The length of the plug 15 is on the order of several percent. As a result, the fluid is doubled in the clearance gap between the valve plug 15 and the inner peripheral surface of the cage 7 and the narrowest gap between the inner peripheral surface of the cage 7 and the low opening flow rate characteristic portion 31 of the valve plug 15. Will be. More preferably, as shown in FIGS. 4 (1) and (2), the narrowest gap a between the inner peripheral surface of the cage 7 and the low opening flow rate characteristic portion 31 of the valve plug 15 when the opening degree is around 5%. The flow path area at −a is designed to be equal to or less than the clearance gap b−b between the valve plug 15 and the inner peripheral surface of the cage 7. If designed in this way, a high Rb (ratio Cvmax / Cvmin between the adjustable maximum flow rate Cvmax and the minimum flow rate Cvmin) can be realized in the low opening flow rate characteristic unit 31, and therefore the flow rate control window 13 at the lowest end of the cage 7. Can be disposed in the vicinity of the seat portion of the cage, and it is possible to greatly prevent a gap flow from being generated just before the clearance between the cage inner peripheral surface 7 and the valve plug 15 at a low opening, and generation of vibrations caused by this gap flow Can be greatly reduced.
Further, the length from the seat surface 19 of the valve plug 15 to the lower end of the low opening flow rate characteristic portion 31 is preferably about 20% of the distance that the valve plug 15 moves from the maximum opening to the minimum opening. .
As a result, high rangeability can be realized, and both improvement in controllability at a low opening and securing of a Cv value at a high opening can be achieved.
The straight portion 39 may have a length of about 1 to 2 mm between the upper end of the low opening flow rate characteristic portion 31 of the valve plug 15 and the seat surface 19.
However, these specific dimensions are merely examples, and are appropriately set according to the maximum flow rate, differential pressure, fluid type, and the like.

Next, the operation will be described. 5- (1) is a cross-sectional view of the plug and cage in the state of 0% opening, FIG. 5- (2) is a cross-sectional view of the plug and cage in the state of low opening, and an enlarged view of part C, FIG. (3) shows a cross-sectional view of the plug and cage in a state where the opening degree is 100%.
When the valve shaft 18 is operated upward by an operation unit (not shown) or manually from the state of 0% opening in FIG. 5-(1), the flow control window 13 is closed by the valve plug 15, and the seat surface of the valve plug 15 The valve plug 15 gradually moves upward from a state in which 19 is seated on the valve seat 14 and is in close contact therewith.

  Then, the flow control window 13 and the low opening flow rate characteristic unit 31 are gradually communicated, and the flow control window 13 that has been closed by the valve plug 15 is opened. FIG. 5- (2) shows a low opening state when the flow control window 13 and the low opening flow rate characteristic unit 31 communicate with each other. As shown in the enlarged view C of FIG. 5-2, only the flow control window 13 at the lowermost end communicates with the low opening flow rate characteristic unit 31, and between the low opening flow rate characteristic unit 31 and the inner wall of the cage 7. The fluid flows from the upstream flow path 3 to the downstream flow path 4 in a state where the flow resistance is large through the formed very thin flow path.

When the valve plug 15 is further operated upward, more flow rate control windows 13 are opened, and a flow path is established through which a fluid can flow without going through the low opening flow rate characteristic unit 31. The resistance becomes smaller and a large flow rate flows. Eventually, when the 100% opening shown in FIG. 5- (3) is reached, the majority of the flow control windows 13 are opened.
FIG. 6 shows flow rate characteristic curves from 0 to 100% of the comparative example and the first embodiment. Moreover, FIG. 7 shows the flow rate characteristic curve to 0-14% opening degree of a comparative example and Embodiment 1. FIG.

Here, the valve device of the comparative example will be described. FIG. 2- (2) shows a sectional view and an enlarged view of a plug of a valve device as a comparative example.
The difference from the valve device of the first embodiment described above is only the shape of the valve plug. The valve plug 115 of the comparative example does not have the low opening flow rate characteristic portion 31 of the first embodiment, and the seat surface 119. Is provided at the lowermost end of the valve plug. Other parts such as the valve stem 18 and the cage 7 are all provided in the same manner as in the first embodiment.

  The operation of the valve device of the comparative example will be described. When the seat surface 119 of the valve plug 115 and the valve seat 14 of the cage 7 are separated from each other and the flow control window 13 at the lowermost end is opened, the valve device of the first embodiment is used. Since no low opening flow rate characteristic unit 31 is provided, the flow rate increases rapidly in the low opening range as compared with the valve device of the first embodiment. When the opening degree is further increased and a high opening degree region is reached, the relationship between the operation amount of the valve plugs 15 and 115 and the increase amount of the flow rate does not change much between the valve device of the first embodiment and the valve device of the comparative example.

For the reasons described above, as shown in FIGS. 6 and 7, the gradients of the valve device of the first embodiment and the valve device of the comparative example are substantially the same in the high opening region. In the low opening region, the flow rate does not increase at a stretch even when the valve device of the first embodiment is the same operation amount as the valve device of the comparative example. In the first embodiment, at a low opening, the fluid flows through a gap between the cage inner wall and the low opening flow rate characteristic portion 31 on the peripheral surface of the lower end of the plug, without involving a complicated configuration and an increase in size. The controllability of the low flow rate at the time of low opening can be improved.
In addition, since the control at a low opening is stabilized and vibration is reduced, reliability is improved, and low stress design can be performed by reducing the vibration. Furthermore, the lifetime can be extended.
In particular, according to the first embodiment, as shown in FIG. 7, a remarkable effect can be obtained in the flow characteristic at the beginning of opening where the opening degree is about 0% to 14%.
In the first embodiment, an example in which the flow control window 13 and the opening 33 are circular has been shown, but the shape of the flow control window 13 and the opening 33 is not limited to a circle, and may be an ellipse, a rectangle, or the like. .
Moreover, although the example which provides the cage 7 in three divisions was shown, it may be provided so that it cannot be divided, or may be provided so as to be further divided into a plurality.
Moreover, although the example in which the cage 7 and the valve body 1 are screwed is shown, the cage 7 may be fixed to the valve body by other fixing means without being screwed.
In addition, an example in which the shape of the contact cross section between the inner wall of the cage 7 and the outer periphery of the valve plug 15 that slides is shown as a circle. May be another shape, such as an ellipse.
Moreover, although the example which flows toward the upper direction from the downward direction of the valve plug 15 was shown about the flow direction, you may set a reverse flow, ie, a flow direction so that it may flow toward the downward direction from the upper direction of the valve plug 15. .

Reference Example 1
8 (1) is a cross-sectional view of the plug of the valve device according to Reference Example 1, FIG. 8 (2) is an enlarged view of portion E in FIG. 8 (1), and FIG. 8 (3) is FIG. 8 (1). The figure seen from below is shown.
The difference from the valve device of the first embodiment described above is only the shape of the valve plug, and the low opening flow rate characteristic unit 332 of the valve plug 315 of the reference example 1 and the low opening flow rate characteristic unit 31 of the first embodiment. The other parts such as the valve stem 18 and the cage 7 are all provided in the same manner as the valve device of the first embodiment.

As shown in FIGS. 8 (1), (2), and (3), the low opening flow rate characteristic portion 332 of the valve device of Reference Example 1 is provided below the lower end portion of the valve plug 315 and the seat surface 319. Yes.
Although the outer diameter of the valve plug 315 below the seat surface 319 is smaller than the diameter in contact with the outer periphery of the cage, it has a substantially constant value and is not formed with a gradient as in the first embodiment, and is parallel to the valve shaft 318. It is straight. And the notch part is provided in the substantially triangular shape in the position corresponding to the location where the flow control window 13 of the cage 7 is provided, and the low opening flow rate characteristic part 332 is formed. The notch which is the low opening flow rate characteristic portion 332 penetrates from the outer peripheral surface of the valve plug 315 to the inner peripheral surface.

  Next, the operation will be described. When the valve shaft 318 is operated upward by an operation unit (not shown) or manually from the state where the opening degree is 0%, the flow control window 13 is closed by the valve plug 315 and the seat surface 319 of the valve plug is seated on the valve seat 14. The valve plug 315 gradually moves upward from the close contact state.

Then, the flow control window 13 and the low opening flow rate characteristic portion 332 are gradually communicated, and the flow control window 13 closed by the valve plug 315 is opened. According to the reference example 1, the notch is provided in a substantially triangular shape at a position corresponding to the location where the flow control window 13 of the cage 7 is provided. Therefore, at the low opening, the apex of the substantially triangular cutout portion, which is the low opening flow rate characteristic portion 332, communicates with the flow control window 13 first, so that the flow rate does not increase rapidly, and the inside of the lower end of the plug By connecting the peripheral surface and the outer peripheral surface, it is possible to improve the controllability of the low flow rate at the time of the low opening without involving a complicated configuration and an increase in size. As in the first embodiment, according to the first reference example, as shown in FIG. 7, a remarkable effect can be obtained in the flow rate characteristics at the opening degree where the opening degree is about 0% to 14%.
In addition, although the reference example 1 shows an example in which the shape of the notch is substantially triangular, the shape of the notch is substantially rectangular, semicircular, trapezoidal, or the like, and the flow rate does not increase suddenly at a low opening. A shape that allows the inner peripheral surface and the outer peripheral surface of the lower end of the valve plug 315 to communicate with each other can be employed.

Reference Example 2
9 (1) is a cross-sectional view of the plug of the valve device according to Reference Example 2 of the present application, FIG. 9 (2) is an enlarged view of a portion F of FIG. 9 (1), and FIG. 9 (3) is FIG. 9 (1). FIG. 9 (4) shows a side view of the plug of Reference Example 2 as seen from below.
The difference from the valve device of the first embodiment described above is only the shape of the valve plug, and the low opening flow rate characteristic unit 432 of the valve plug 415 of the reference example 2 and the low opening flow rate characteristic unit 31 of the first embodiment. The other parts such as the valve stem 18 and the cage 7 are all provided in the same manner as the valve device of the first embodiment.

As shown in FIGS. 9 (1), (2), (3), and (4), the low opening flow rate characteristic portion 432 of the valve device of Reference Example 2 has a lower end portion of the valve plug 415 and a lower portion of the seat surface 419. Is provided.
Although the outer diameter of the valve plug 415 below the seat surface 419 is smaller than the diameter in contact with the outer periphery of the cage, it is a substantially constant value and is not formed with a gradient as in the first embodiment, and is parallel to the valve shaft 418. It is straight. A notch portion is provided in a substantially rectangular shape at a position corresponding to the location where the flow rate control window 13 of the cage 7 is provided, and a low opening flow rate characteristic portion 432 is formed. The notch portion which is the low opening flow rate characteristic portion 432 is not penetrated to the inner peripheral surface of the valve plug 415 and is provided so that the depth of the notch portion becomes deeper toward the lower end of the valve plug 415. ing.

  Next, the operation will be described. When the valve shaft 418 is operated upward from the 0% opening degree by an operating unit (not shown) or manually, the flow control window 13 is closed by the valve plug 415 and the seat surface 419 of the valve plug is seated on the valve seat 14. The valve plug 415 gradually moves upward from the close contact state.

  Then, the flow control window 13 and the low opening flow rate characteristic unit 432 are gradually communicated, and the flow control window 13 closed by the valve plug 415 is opened. According to Reference Example 2, the notch that is the low opening flow rate characteristic part 432 is not penetrated to the inner peripheral surface of the valve plug 415, and the depth of the notch becomes closer to the lower end of the valve plug 415. Is provided to be deep. Therefore, since the portion where the depth of the upper end portion of the notch portion is not deep at the low opening degree is communicated with the flow control window 13 first, the low opening flow rate characteristic of the lower end of the plug does not increase rapidly. By flowing through the gap between the portion 332 and the inner wall surface of the cage 7, it is possible to improve the controllability of the low flow rate at the time of low opening without complicated structure and increase in size. As in the first embodiment, according to the present reference example 2, a remarkable effect can be obtained in the flow rate characteristics at the beginning of opening when the opening degree is about 0% to 14% as shown in FIG.

Reference Example 3.
10 (1) is a cross-sectional view of the plug of the valve device according to Reference Example 3 of the present application, FIG. 10 (2) is an enlarged view of a portion G of FIG. 10 (1), and FIG. 10 (3) is FIG. FIG. 10 (4) shows a side view of the plug of Reference Example 3 as seen from below.
The difference from the valve device of the first embodiment described above is only the shape of the valve plug, and the low opening flow rate characteristic unit 532 of the valve plug 515 of the reference example 3 and the low opening flow rate characteristic unit 31 of the first embodiment. The other parts such as the valve stem 18 and the cage 7 are all provided in the same manner as the valve device of the first embodiment.

As shown in FIGS. 10 (1), (2), (3), and (4), the low opening flow rate characteristic portion 532 of the valve device of Reference Example 3 is provided at the lower end portion of the valve plug 515 and below the seat surface 519. Is provided.
Although the outer diameter of the valve plug 515 below the seat surface 519 is smaller than the diameter in contact with the outer periphery of the cage, it is a substantially constant value and has no gradient as in the first embodiment, and is parallel to the valve shaft 518. It is straight. And the notch part is provided in the substantially triangular shape in the position corresponding to the location where the flow control window 13 of the cage 7 is provided, and the low opening flow rate characteristic part 532 is formed. The notch portion which is the low opening flow rate characteristic portion 532 is not penetrated to the inner peripheral surface of the valve plug 515 and is provided so that the depth of the notch portion becomes longer toward the lower end of the valve plug 515. ing.

  Next, the operation will be described. When the valve shaft 518 is operated upward from an open state of 0% by an operating unit (not shown) or manually, the flow control window 13 is closed by the valve plug 515 and the seat surface 519 of the valve plug is seated on the valve seat 14. The valve plug 515 gradually moves upward from the close contact state.

Then, the flow rate control window 13 and the low opening flow rate characteristic unit 532 are gradually communicated, and the flow rate control window 13 closed by the valve plug 515 is opened. According to the reference example 3, the notch part which is provided with the notch part in a substantially triangular shape at the position corresponding to the place where the flow rate control window 13 of the cage 7 is provided and is the low opening degree flow characteristic part 532 Is not penetrated to the inner peripheral surface of the valve plug 415, and is provided such that the depth of the notch becomes longer toward the lower end of the valve plug 415. Therefore, at the low opening, the notch portion is a substantially triangular vertex and the portion is not deep, so the first communication with the flow control window 13 is greater than in Reference Examples 1 and 2. By flowing through the gap between the low opening flow rate characteristic portion 532 at the lower end of the plug and the inner peripheral surface of the cage 7 without suddenly increasing the flow rate, the low opening degree is not accompanied by a complicated configuration and an increase in size. The controllability of the low flow rate at the time can be improved. As in the first embodiment, according to the present reference example 3, a remarkable effect can be obtained in the flow rate characteristics at the beginning of opening where the opening degree is about 0% to 14% as shown in FIG.
In Reference Examples 2 and 3, an example in which the shape of the notch portion is a substantially triangular shape and a substantially rectangular shape has been shown. However, the shape of the notch portion is semicircular, trapezoidal, etc., and the flow rate increases rapidly at a low opening. Instead, it is possible to adopt a shape that can flow the gap between the low opening flow rate characteristic portions 432 and 532 at the lower end of the plug and the outer peripheral surface of the plug.

  As described above, the cage valve according to the present invention is suitable for use in a valve that controls a wide flow rate from a small flow rate to a large flow rate.

It is a principal part longitudinal cross-sectional view which shows the state by which the valve apparatus by Embodiment 1 of this invention is substantially fully open. It is sectional drawing of the plug of Embodiment 1 of this invention, and the enlarged view of A part. It is sectional drawing of the plug of the valve apparatus which is a comparative example of this invention, and the enlarged view of B part. It is a figure which shows the dimension of the plug of Embodiment 1 of this invention. It is a figure which shows sectional drawing of the plug and cage of the state of 5% of opening degree in Embodiment 1 of this invention. FIG. 4- (2) is an enlarged view of part E in FIG. 4- (1). It is a figure which shows sectional drawing of the plug and cage of the state of opening degree 0% in Embodiment 1 of this invention. It is a figure which shows the sectional view of a plug and a cage in the state of 10% of opening degree in Embodiment 1 of this invention, and the enlarged view of C part. It is a figure which shows sectional drawing of the plug and cage of the state of 100% of opening degree in Embodiment 1 of this invention. It is a flow characteristic curve to 0-100% opening degree of the comparative example and Embodiment 1 of this invention. It is a flow characteristic curve to 0-14% opening degree of the comparative example and Embodiment 1 of this invention. FIG. 8- (1) is a cross-sectional view of the plug of the valve device according to Reference Example 1, FIG. 8- (2) is an enlarged view of portion E in FIG. 8- (1), and FIG. 8- (3) is FIG. -(1) seen from below. 9- (1) is a cross-sectional view of the plug of the valve device according to Reference Example 2 of the present application, FIG. 9- (2) is an enlarged view of portion F of FIG. 9- (1), and FIG. 9- (3) is FIG. FIG. 9- (4) is a side view of the plug of Reference Example 2. FIG. 10- (1) is a cross-sectional view of the plug of the valve device according to Reference Example 3 of the present application, FIG. 10- (2) is an enlarged view of a portion G of FIG. 10- (1), and FIG. FIG. 10- (4) is a side view of the plug of Reference Example 3. FIG. It is sectional drawing which shows the cage valve of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Valve main body 2 Partition wall 7 Cage 7A Upper cage part 7B Lower cage part 13 Flow control window 15,215,315,415,515 Valve plug 31,232,332,432,532 Low opening flow rate characteristic part

The cage valve according to the present invention includes a cage that is fixed in one chamber divided by a partition wall that divides the inside of the valve body into an upstream side and a downstream side, and that has a plurality of windows on a peripheral wall, and slides in the cage. A valve plug that opens and closes the window of the cage, and a lower opening peripheral surface of the valve plug is provided with a low opening flow rate characteristic portion having a gap with the inner wall of the cage on the lower peripheral surface of the valve plug. the gap between the low opening flow characteristic portion and the cage inner wall Ri of wider as opening increases within the low opening, and, at around 5% opening, the inner peripheral surface of the cage and the valve plug The flow path area at the narrowest gap with the low opening flow rate characteristic portion is equal to or less than the clearance gap area between the valve plug and the inner circumferential surface of the cage, and the upper end of the low opening flow rate characteristic portion of the valve plug circumferential surface A seat portion, and from the valve plug seat portion Serial length to the lower end of the lower opening flow characteristic portion, the valve plug is one that is 20% of the length of the distance traveled to the minimum opening degree from the maximum opening degree.

As shown in FIGS. 2- (1) and 3- (2) , the valve plug 15 is provided with a low opening flow rate characteristic portion 31 for providing a clearance with the inner wall of the cage on the lower peripheral surface of the cage 7. ing.
A seat surface 19 is provided at the upper end of the low opening flow rate characteristic portion 31 on the peripheral surface of the valve plug 15 via a straight portion 39 having a slight length, and the low opening flow rate characteristic on the lower peripheral surface of the valve plug 15 is provided. The low opening flow rate characteristic portion 31 is in relation to the outer peripheral surface of the valve plug 15 that slides with the cage 7 so that the gap between the portion 31 and the inner wall of the cage becomes wider as the opening increases within the range of the low opening. It is formed at a very small angle.
That is, the lower end of the seat opening 19, that is, the outer periphery of the uppermost end of the low opening flow rate characteristic part 31 is slightly larger than the outer peripheral diameter of the lower end flow rate characteristic part 31. The outer peripheral surface of the opening flow rate characteristic portion 31 is not parallel to the contact surface between the valve plug 15 and the cage 7 but is provided at a slight angle.
The straight portion 39 is provided to ensure the dimensional stability of the low opening flow rate characteristic unit 31 and is not necessarily required. The upper end of the low opening flow rate characteristic unit 31 is not necessarily provided via the straight portion 39. A sheet surface 19 may be provided.

DESCRIPTION OF SYMBOLS 1 Valve main body 2 Partition wall 7 Cage 7A Upper cage part 7B Lower cage part 13 Flow control window 15, 115 , 315, 415, 515 Valve plug 31, 232, 432, 532 Low opening flow rate characteristic part

Claims (3)

A cage that is fixed in one chamber divided by a partition wall that divides the inside of the valve body into an upstream side and a downstream side and has a plurality of windows on the peripheral wall, and slides in the cage to open and close the window of the cage In a cage valve with a valve plug,
A cage valve characterized in that a low opening flow rate characteristic portion having a gap with the inner wall of the cage is provided on the lower peripheral surface of the valve plug. The cage valve according to claim 1, wherein
The gap between the low opening flow rate characteristic portion on the lower peripheral surface of the valve plug and the cage inner wall becomes wider as the opening increases within the low opening range, and the low opening flow characteristic portion on the valve plug peripheral surface A cage valve characterized in that a seat part is provided at the upper end of the cage. A cage that is fixed in one chamber divided by a partition wall that divides the inside of the valve body into an upstream side and a downstream side and has a plurality of windows on the peripheral wall, and slides in the cage to open and close the window of the cage In a cage valve with a tubular valve plug,
A low opening flow rate characteristic portion that communicates the outer surface and the inner surface of the valve plug is provided on the lower end peripheral surface of the valve plug, and a seat portion is provided at the upper end of the low opening flow rate characteristic portion of the valve plug peripheral surface. Cage valve characterized by.

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