JPH0133886Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field This invention relates to a cage-type two-seat control valve used for controlling the flow rate of high-temperature or low-temperature fluids.

(B) Prior Art As shown in the side sectional view of FIG. 2, the conventional cage type two-seat control valve has a flanged hollow cylindrical body connected to the valve body 1 through annular gaskets 2, 3, and 4. A cage 5 is housed in the flange portion 6 of the valve body 1.
The flange portion of the cage 5 is fixed by being pressed by a lid portion 8 joined with a fastening bolt 7, and the cage 5 further includes a piston 10 having a skirt portion 9 therein. The inner valve 11 is housed in a slidable manner. The inner valve 11 is taken out to the outside through a gland part 13 provided at the center of the lid part 8 so that the valve shaft 12 connected to the center of the piston 10 is kept airtight or liquid-tight. , is connected to a direct-drive type drive unit consisting of an air cylinder or an air diaphragm (not shown), and the operation of this drive unit causes the inner valve 11 to move vertically along its inner circumferential surface using the cage 5 as a guide. The skirt portion 9 is adapted to slide and adjust the degree of opening of a plurality of openings 14 equally spaced in the cage 5 with respect to its axis. Furthermore, in the inner valve 11, the outer diameter of the skirt portion 9 is slightly smaller than that of the piston 10, and accordingly, in the cage 5, the inner diameter is larger in the upper part and slightly smaller in the middle part. The lower end fitted into the opening of the partition plate 15 of the valve body 1 is further made smaller, and each stepped portion is formed into a part of a concave cone, and the stepped portion between the piston 10 and the skirt portion 9 and the skirt An upper valve seat 16 and a lower valve seat 1 that fit into each other and form a sealing effect with a part of a convex cone formed at the lower end of the portion 9, respectively.
7, and when the inner valve 11 is in the illustrated position, the inner valve 11 completely blocks the inlet I and the outlet O of the valve body 1.

Since the conventional device is constructed in this way, no leakage from the sealing portions of the gaskets 2, 3, and 4 occurs when the fluid passed through the valve body 1 is at room temperature. For example, when the fluid is at a high temperature, the valve body 1 is made of heat-resistant cast steel (for example, JIS SCPHZ), and the cage 5 and the inner valve 11 are made of heat-resistant stainless steel (for example, JIS SCF).
13), the linear expansion coefficient of the cage 5 material is approximately 1.5 times larger than that of the valve body 1 material, and the cage 5 housed inside the valve body 1 is Because the cage 5 is held at a temperature closer to the fluid temperature than the valve body 1, the cage 5 becomes higher temperature than the valve body 1, and a temperature difference occurs between the two, which causes different thermal strains in the valve body 1 and the cage 5. As a result, these components interfere with each other, and the sealing action of the seal portions 2, 3, and 4 may not be complete, resulting in internal leakage or inability to operate the inner valve 11 smoothly.

(c) Purpose This invention aims to solve the above-mentioned problems faced by the conventional device by providing a cage-type two-seat control valve that can be used regardless of the temperature of the fluid passed inside without impairing the function of the control valve. First, it is an object of the present invention to provide a cage-type two-seat control valve that can prevent the above-mentioned internal leakage and that allows the inner valve to operate smoothly at all times.

(D) Structure The cage-type two-seat control valve according to this invention includes a valve body 1 divided into an inlet I and an outlet O by a partition plate 15 having an opening in the center, and a valve body 1 that is concentric with the opening. A hollow cylindrical cage 5 having a lower end engaged with the partition plate 15 and having a plurality of through holes 14 bored in the side wall near the lower end, and a cage 5 having a hollow cylindrical cage 5 that slides therein. The valve shaft 12 is freely engaged and driven by a drive section provided outside the valve body 1.
and a piston-shaped inner valve 11 having a skirt portion 9 which is driven in the vertical direction via the inner valve 11, and a piston-shaped inner valve 11 having a skirt portion 9, and a portion where the shoulder portion and the lower end surface of the inner valve 11 abut, respectively, when the inner valve 11 is closed. , in a cage-type two-seat control valve formed with an upper valve seat 16 and a lower valve seat 17 for blocking the flow of fluid from the inflow part to the outflow part, the lower valve seat 17 is connected to the It is formed on the upper edge of the opening of the partition plate 15 and close to the outside of this lower valve seat 17,
It is constructed by disposing an annular groove 21 in the partition plate, with which the lower end of the cage 15 is engaged with a gap in both the downward and outer circumferential directions.

(E) Embodiment FIG. 1 is a side sectional view of an embodiment of the device according to this invention, and the same components as those in the conventional device shown in FIG. 2 described earlier are designated by the same reference numerals. and the explanation thereof will be omitted.
The components in which this embodiment device differs from the conventional device are the valve body 1 and the cage 5, and the differences are as follows.

Regarding the valve body 1, the inner valve 11 is connected to the skirt portion 9.
A lower valve seat 17, which blocks the inflow part I and the outflow part O by pressing at the lower end, is provided integrally with the opening of the partition plate 15 of the valve body 1, instead of with the conventional cage 5. At the same time, conventional cage 5
The annular gasket 2 which was held between the lower end and the partition plate 15 of the valve body 1 is removed, and an annular groove 21 into which the lower end of the cage 5 is inserted is provided adjacent to the lower valve seat 17. The depth of the annular groove 21 is made slightly deeper than the lower end of the cage 5 inserted therein, and the width of the annular groove 21 is made slightly wider than the thickness of the lower end of the cage 5. It is that you are.

Regarding the cage 5, the length of the portion below the opening 14 is shortened, and the inner circumferential portion is slightly removed as opposed to the conventional outer circumferential portion, and the thinned lower end is grooved into the annular groove 21. It is inserted with a slight gap left with respect to the bottom, and at that time, a slight gap is also created between the lower end surface of the inner circumference removed as described above and the partition plate 15 of the valve body 1. At the same time, a slight gap is created in the width direction between the outer peripheral surface of the lower end portion and the groove wall of the annular groove 21, and the flange portion of the cage 5 is connected to the lid portion via the annular gaskets 3 and 4. 8 and the valve body 1, and is housed inside the valve body 1 as if suspended.

In the device of this embodiment, the structures of the valve body 1 and the cage 5 are different from those of the conventional device as described above, so that the following changes occur in its operation.

For example, if high-temperature fluid is passed through the valve body 1, the valve body 1 and the cage 5 are made of conventional materials, so as mentioned above,
A dimensional difference occurs between the valve body 1 and the cage 5 due to thermal expansion, but the dimensional difference in the vertical direction is
As described above, the liquid is absorbed by the gaps left between the stepped lower end surface of the valve body 1 and the bottom of the annular groove 21 and the partition plate 15 of the valve body 1 without any problem. On the other hand, since the flange portion 6 of the valve body 1 has a sufficient wall thickness, the deformation of the cage 5 is suppressed, and the deformation of the lower end of the cage 5 is reduced due to the dimensional difference in the lateral direction, that is, the radial direction. The valve body 1 is not deformed because it is absorbed by the gap in the width direction. Therefore, the sealing action of the seal portions 3, 4 is completely performed and no leakage occurs. Furthermore, since the cage 5 is suspended and held within the valve body 1, no thermal strain occurs at least in the area where the inner valve 11 slides, so that the upper and lower valve seats 16, 17
functions normally, and the operation of the inner valve 11 by the aforementioned drive section is always performed smoothly.

FIG. 3 is a partial side sectional view showing the main parts of an apparatus according to another embodiment of the invention. In this other embodiment of the device, a lower valve seat 17 pressed by the skirt portion 9 of the inner valve 11 and an annular groove 2 into which the thinned portion of the lower end of the cage 5 are inserted.
In the embodiment shown in FIG. 1, 1 is an annular member 2 which has a flange part at the upper part of the outer periphery and a threaded part below the flange part.
2, a threaded portion into which this threaded portion is screwed is provided on the valve body 1, and the threaded portion of the valve body 1 is
The annular member 22 is screwed into the valve body 1 using a plurality of blind holes 23 for inserting a tool, which are equally distributed on the flange portion. In this way, when the lower valve seat 17 becomes worn out, only the annular member 22 can be replaced, which facilitates maintenance. Since the operation is exactly the same as that of the embodiment shown in FIG. 1, the explanation will be omitted.

(f) Effects In the cage type double-seat control valve according to this invention, regardless of the temperature of the fluid passed through it, the dimensional difference due to the difference in thermal expansion between the valve body and the cage is Since both the main body and the cage are designed to be suppressed or absorbed so as not to interfere with their respective functions, it is possible to completely prevent internal leakage from the sealing part, and to prevent the inner valve from being opened by the drive part. Movement can be performed smoothly at all times.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of an embodiment of the device according to this invention, FIG. 2 is a side sectional view of a conventional device, and FIG. 3 is a partial side sectional view of another embodiment of the device according to the invention. be. 1... Valve body, 3, 4... Annular gasket, 5
... Cage, 9 ... Skirt part, 10 ... Viston, 11 ... Inner valve, 12 ... Valve stem, 14 ... Opening (through hole), 15 ... Partition plate, 16 ... Upper end valve seat, 17... lower valve seat, 21... annular groove, I...
Inflow part, O...outflow part.

Claims (1)

[Scope of utility model registration request] A valve body is divided into an inflow part and an outflow part by a partition plate having an opening in the center, and a lower end is engaged with the partition plate so as to be located concentrically with the opening, and the lower end is near the lower end. A hollow cylindrical cage with a plurality of through holes bored in the side wall, the cage is slidably engaged with the inside of the cage, and is driven vertically via the valve shaft by a drive section provided outside the valve body. and a piston-shaped inner valve having a skirt portion, which is driven by a piston-shaped inner valve having a skirt portion, and a portion where a shoulder portion and a lower end surface of the inner valve come into contact with each other when the inner valve is closed. In a cage-type double-seat control valve formed with an upper valve seat and a lower valve seat for blocking fluid flow, the lower valve seat is formed at the upper edge of the opening of the partition plate of the valve body, and
The cage type is characterized in that the partition plate is provided with an annular groove adjacent to the outside of the lower valve seat, with which the lower end of the cage is engaged with a gap maintained downwardly and in the outer circumferential direction. Seat control valve.