JPH03219184A - Valve device - Google Patents

Abstract

PURPOSE:To improve valve closing performance with simple construction by providing primary and secondary side seats, either shiftable, on a seat ring and a valve plug, and forming a communication hole having a pressure regulating valve within the valve plug. CONSTITUTION:A valve body 10 is separated into primary and secondary side flow passages 12A and 12B with a division 11, and a seat ring 13 is provided at the center of the division 11. The center hole of the seat ring 13 forms a fluid communication hole 16, and a primary side seat (fixed) 17 and a secondary side seat (movable) 18 are provided at upper and lower open ends of the hole 16. Also, primary and secondary side seat sections 32 and 33 are so formed on the external surface of the valve plug 30 as to correspond to the primary and secondary side seat sections 17 and 18 of the seat ring 13. In addition, a communication hole 37 having a built-in pressure regulating valve 38 is formed within the valve plug 30. according to the aforesaid construction, the proper seating of the seat sections 32 and 33 on top of each other can be ensured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a valve device having a contour type valve plug, and particularly to a valve device suitable for use in controlling high-pressure fluid.

[Prior Art] In general, in a valve device that controls high-pressure fluid, it is necessary to emphasize not only the characteristics for control use but also the valve closing function. If the valve closing function is incomplete and there is a very small amount of fluid leaking when the valve is fully open,
Due to the high differential pressure, a type of captivity erosion called wire trowing occurs in this leakage flow, which locally erodes the seat surfaces of the seal 1~ring and valve plug, reducing the amount of fluid leakage when fully closed. This is because if the number of valves increases further, the valve closing function will eventually be completely lost and the valve will become unusable in a short period of time. Therefore, as one method to solve this problem, conventionally, as shown in FIG. It is known that these valves are provided respectively to improve the valve closing performance.

[Problem M to be solved by the invention] However, in such a method using two seat parts, if the leak performance of both seat parts is to be the same, the differential pressure condition applied to each seat surface is is divided into equal parts,
This will provide the best performance, but in order to actually achieve this condition, the distance between the two seat parts 3.4 formed on the one seat ring 1 and the two seat parts 3.4 formed on the valve 1 lug 2 must be adjusted.
It is necessary to make the intervals between the two sheet parts 5.6 equal to M density, which requires high machining accuracy, and there is also a drawback that it is necessary to test the leakage characteristics of each sheet part after machining.

Additionally, if a confirmation test reveals that there is a significant difference in the leak characteristics of each sheet surface, additional work must be performed to readjust the seat portion.

Therefore, the present invention has been made in view of the above-mentioned conventional problems, and its purpose is to improve valve closing performance with a relatively simple configuration and to prevent the occurrence of cavitation called wire drawing phenomenon. An object of the present invention is to provide a valve device that can prevent the above.

[Means for Solving the Problems] The present invention has been made to achieve the above object, and a first aspect of the present invention is to provide a cylindrical seat ring having a fluid passage hole, and a sliding member inside the seat ring. In a valve device equipped with a valve plug which is freely arranged and controls opening and closing of the fluid passage hole, the seat ring and the valve plug have a primary side seat part and a next side seat part which are spaced apart from each other in the axial direction and seat each other when fully closed. In addition, one of the two seat parts of the seat ring or the valve plug is formed to be movable in the axial direction.

A second invention is a second invention in which, in the first invention, a communication hole is provided that communicates the space formed between the seat ring, the valve plug, and the first and secondary seat parts with the downstream side of the secondary seat part. The valve plug is formed within the valve plug, and a pressure regulating valve is incorporated into the communication hole.

[Operation J] In the present invention, the movable seat portion provided on the seat ring or valve plug is moved by contact with the mating seat portion when the valve is closed, thereby absorbing machining errors. The pressure regulating valve built into the valve plug is operated by the fluid pressure in the space formed between the seat ring, the valve plug, and the first and second side seat parts when the valve is closed, and is maintained at a constant pressure. When the pressure regulating valve opens, a portion of the fluid in the space flows out downstream through a communication hole formed in the valve plug.

[Example] The present invention will be described in detail below based on an example shown in the drawings.

FIG. 1 is a sectional view of the main part of an embodiment of the valve device according to the present invention when the valve is closed, and FIG. 2 is a sectional view of the main part of the valve device in a small opening state. In these figures, 10 is connected by a partition wall 11 to an upstream 1!1ll (-next side) flow path 12A and a downstream (!I) flow path 12A.
(Secondary side) Shoulder wall valve body partitioned into flow path 12B, 13
is a cylindrical seat ring screwed into a screw hole 14 formed in the center of the partition wall 11 via a gas get 15, and the center hole of this seat link 13 forms a fluid passage hole 16;
Further, primary and secondary seat portions 17 and 18 are formed at the upper and lower opening ends of the fluid passage hole 16, respectively.

In this case, the next-side seat portion 17 is formed on the inner peripheral surface of the lower end side of the fluid passage hole 16, thereby forming a fixed seat portion. On the other hand, the secondary seat portion 18 includes an inner periphery of the upper end opening of a cylindrical floating seat ring 20 that is fitted to the upper end inner periphery of the fluid passage hole 16 via a seal member 2) so as to be vertically movable. A movable seat portion is formed by being formed on a surface.

Reference numeral 22 denotes a guide disposed above and coaxially with the seat ring 13 to slidably guide and hold a valve plug 30, which will be described later.This guide 22 is formed into a cylindrical body.
- A flange 22A is integrally formed on the outer surface of the F end, and this flange 22A is integrally formed on the outer surface of the F end.
2A is fitted into the closing portion 23 provided at the center of the upper surface of the valve body 10 via a gasket 24, and the guide 2
The lower end of the seat ring 2 is fitted onto the upper end outer circumferential surface of the seat ring 13 and the floating seat ring 20. A communication hole 26 is formed in the guide 22 in the radial direction and communicates the center hole 28 with the secondary flow path 12B of the valve body 10, and an annular groove 29 is formed in the inner peripheral surface of the communication hole 26. It is formed correspondingly.

Reference numeral 27 denotes an upper cover that is fitted into the upper opening 23 of the valve body 10 and fixed with bolts and nuts (not shown).

The valve plug 30 is a contour type valve lug 15.
The lower part is slidably fitted into the center hole 28 of the guide 22, the floating seat ring 20, and the seat ring 13, and is moved up and down by the valve shaft 31 to open the fluid passage hole 16. Configured to control Kaida. Primary and secondary seat portions 32.33 are formed on the outer circumferential surface of the lower end portion and the outer circumferential surface of the intermediate portion of the valve plug 30, corresponding to the primary and secondary seat portions 17.18 of the seat ring 13, respectively. There is. These seat portions 32,33 are all formed directly on the valve plug 30 to form a fixed seat portion, and are seated on the primary steel, secondary side seat portions 17,18 of the seat ring 13 at the time of the valve 11. - A first characteristic portion 3 having a substantially conical shape is provided below the next seat portion 32.
5 is formed, and the lower part of the secondary seat part 33 at the middle part of the valve plug 30 is a tapered second characteristic part 36 having a smaller diameter on the lower end side. Also valve plug 3
0 has a communication hole 3 incorporating a pressure regulating valve 38 therein.
7 is formed. The communication hole 37 connects a closed space 40 formed between the seat ring 13 and the valve plug 30 and the primary and secondary seat portions 17, 18, 32, and 33 to the inner peripheral surface of the guide 22 when the valve is closed. and valve plug 3
0 downstream of the valve body 10 via the gap G between the outer circumferential surface of the upper end of the valve body 10 and the communication hole 26! ll flow path 1-2B, one end opening 37a is the upper end circumferential surface of the valve plug 30, and the next side seat part 32 and the second characteristic part 36
The other end opening 37b opens at the outer circumferential surface of the upper end.

The pressure regulating valve 3 incorporated inside the communication hole 37
Reference numeral 8 is a multistage pressure regulating valve that maintains the fluid pressure P2 in the seat ring 13, that is, the space 40 at a constant pressure, and is normally urged downward by the spring force of the spring 41 to close the communication hole 37. When the fluid pressure inside the seat ring 13 reaches a certain pressure 22 or higher, it operates to open the communication hole 37.

The floating seat ring 20 is movable by Δd in the vertical direction by step portions 45 and 46 formed on the inner peripheral surfaces of the seat ring 13 and the guide 22, respectively. Δd is set in consideration of the dimensional error between the seat portions 17 and 18, and 32 and 33, and is approximately 11 rin.

In the valve device having such a configuration, FIG. 1 shows the fully open state immediately after the valve plug 30 is lowered to stop the valve. In this state, the primary side and secondary side seat parts 32.33 of the valve plug 3o are seated on the primary side and secondary side seams 1 to 1-7.18 of the seat ring 13, respectively,
The interior space 40 of the seat ring 13 is a closed space. Furthermore, when the valve plug 30 descends, the secondary seat portion 33 comes into contact with the next seat portions 18 of the floating seats 1 to 20 just before the end of the descent, and if the valve plug 30 continues to descend, the floating seat ring 20 The valve plug 30 is lowered together with the valve plug 30, and the downstream seat portion 32 is brought into contact with the primary seat portion 17. Therefore, the seat part 17 of the seat part 32.33
．． 18 is accurate and secure, and the lowering of the floating seat ring 20 absorbs processing errors of these seat parts, making processing and adjustment work of the seat part easy. In addition, if the seat is properly seated, the valve stop function will improve.
The amount of fluid leakage when the valve is closed can be significantly reduced and prevented.

Here, when used for controlling high-pressure fluid, for example, if the fluid pressure P1 is 160 kg f /cn (G, pressure regulating valve 38
is 17' 2 P + (80kg f / -G
). In the opening state (fluid control state) in which the valve plug 30 is raised and the primary and secondary seat portions 32.33 are separated from the primary and secondary seat portions 17.18, the valve body 1o is opened. The high-pressure fluid at pressure P1 that has flowed into the second flow path 12A flows into the fluid passage hole 16 from the F end opening of the seat ring 13, passes through the annular 7Ji 29 of the guide 22 and the circulation hole 26, and then passes through the F flow path 1.2B.
It is leaked to. At this time, when the fluid with the pressure P1 flows into the fluid passage hole 16 of the seat ring J-3, the pressure of the fluid changes from Pl to P2(], 60 kg f /aIiG→
The pressure is reduced to 80 kg f /cnfG ), and this reduced pressure passes between the secondary side seat portions 18 and 33 and flows into the downstream flow path 12B, further reducing the pressure (p3 -Okg
f/cmtG).

In other words, the present invention uses two seat parts to reduce the pressure in two stages during the control jump.

Next, from this state, the valve plug 3o is gradually lowered, and when the secondary seat part 33 is seated in contact with the secondary seat part 18, the fluid passage holes of the seals 1 to 1-3 are
-6 and the downstream flow path 1.2B are cut off, the fluid pressure P2 in the seat ring 1-3 is -temporally Pt
(=160kgf/cmG) to the same pressure as 1-
rise Immediately after this, when the primary seat part 32 is seated on the primary seat part 17 and the valve is closed, the pressure regulating valve 38 is operated by the pressure P2 in the seat ring 13, and the communication hole 37 is opened as directly reached. . Therefore, a part of the fluid in the seat ring 13 flows through the communication hole 27 and the guide 2.
2 and the valve plug 30, flows out into the downstream flow path 12B through the annular groove 29 and the communication hole 26, and lowers the pressure P2 in the seat ring 13 to 80 kgf/cx+G. Then, when P,, = 80 kgf/a IIG, the spring 41 of the pressure regulating valve 38 and the pressure P2 are balanced, so the regulating valve 38 returns to close the communication hole 27, and from now on, this state will be maintained, i.e. P 1= 16
0 kgf/c [IlG-P 280 kgf
/ aIlG, P 3 = Okg f / r
Hold yd G.

As a result, the seat portion 17.32 and the seat portion 18.33
The differential pressure approximately equal to (= 80 kg f/cxA G
), and by providing the floating seat ring 20 as described above, it is possible to improve the valve closing function of the seat part, so that the amount of fluid leaked by both seal parts can be kept at the same level and reduced. Since the armpit can be made small, erosion in the sheet direction due to cavitation is reduced, and the sea 1 to rectangular performance can be stably maintained for a long period of time.

Note that in the above embodiment, the m-
Although the next seat section 18 is a movable seat section, the present invention is not limited to this, and any one of the four
It is sufficient if both of them constitute the movable seat section.

"Effect of the Invention 1 As explained above, the valve device according to the present invention includes two parts of the seat ring and the valve plug, and one of the seats is arranged in the axial direction of the valve plug. Since it is configured to be movable, it is possible to absorb processing errors in the seat I section, and the seats can be reliably seated together, improving the valve stop function.Therefore, the processing and adjustment of the seat section is easy. It is easy to work, suppresses and prevents cavitation caused by fluid leakage when the valve is stopped, and improves the reliability and durability of the valve device.

Furthermore, the present invention forms a communication hole in which a pressure control valve is incorporated in the valve plug, and communicates the internal space of the sealing ring with the downstream flow path through the communication hole, so that the pressure control valve can reduce the differential pressure. Since it was configured to achieve equal division, the first
It is possible to make the differential pressures applied to a portion of the second seal and the second seal substantially equal, and the leakage performance can be made to be -.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view showing an embodiment of the valve device according to the present invention, showing the state immediately after the valve is closed, Fig. 2 is a cross-sectional view of the main part in a small opening state, and Fig. 3 is a sit ring of the conventional valve device. and FIG. 3 is a cross-sectional view of the valve plug. 10- Valve body, 11... Partition wall, 1.2A... Upstream flow path, 12 B-- Downstream flow path, 13... Seat ring, ] 6... Fluid passage hole, 1
7...-Secondary side seat part, 1.8...Next side seat part, 20...Floating seat ring, 22...Guide, 2
6--Communication hole, 30 valve plug, 32...-Next side seat section, 33-Next side seat section, 37...Communication hole, 38.Pressure control valve, 40..Space.

Claims (1)

[Claims] (1) A valve device comprising a cylindrical seat ring having a fluid passage hole, and a valve plug slidably disposed within the seat ring and controlling opening and closing of the fluid passage hole, the seat ring and the valve plug A primary seat part and a secondary seat part are provided in each of the valve plugs, which are spaced apart in the axial direction and seated against each other when fully closed, and one of the two seat parts of the seat ring or the valve plug is formed to be movable in the axial direction. A valve device characterized by: (2) The valve device according to claim (1), further comprising a communication hole that communicates the space formed between the seat ring, the valve plug, and the first and second side seat parts with the downstream side of the second side seat part. A valve device characterized in that a pressure regulating valve is formed in the valve plug and incorporated in the communication hole.