JP7580331B2 - Ball valve - Google Patents

Description

The present invention relates to a ball valve that is installed in a pipeline that is in a high-temperature environment or in a pipeline through which a high-temperature fluid flows.

Ball valves have been known for some time as valves that open and close pipelines for various fluids. Their basic structure is such that a valve chamber with an open top is provided between the inlet and outlet ports of a casing, a ball-shaped valve body with a valve hole is housed in the valve chamber, a sealing seat ring is pressed against the outer periphery of the valve body, a valve shaft connected to the valve body is passed through a cylindrical bonnet that closes the top of the valve chamber and extends upward, and the valve body is opened and closed by operating the valve shaft to rotate it (see, for example, Patent Document 1).

When such ball valves are installed in pipelines that are in a high-temperature environment, or in pipelines that carry fluids that require a high temperature above a certain level to maintain fluidity, the casings and packings of the ball valves are made from materials with excellent heat resistance.

JP 2009-103242 A

However, the heat-resistant materials used for the casings and packings of the above-mentioned ball valves are limited in variety due to their special characteristics (e.g., expanded graphite), are expensive, and the parts take time to manufacture. This is one of the factors that increases the overall cost of ball valves and lengthens the manufacturing period.

The present invention aims to provide a ball valve that has a heat-resistant structure suitable for installation in pipelines in high-temperature environments or pipelines for high-temperature fluids, and does not require parts made of special heat-resistant materials.

To solve the above problems, the present invention provides a ball valve comprising a casing having a valve chamber with an open top between an inlet port and an outlet port, a ball-shaped valve body housed in the valve chamber, a valve shaft for rotating the valve body, and a bonnet that closes the top of the valve chamber while the valve shaft is passing through it. The ball valve is provided with a main jacket that covers the periphery of the casing and an upper jacket that covers the periphery of the bonnet, and a fluid that cools the casing is passed through the hollow space between the main jacket and the casing, and a fluid that cools the bonnet is passed through the hollow space between the upper jacket and the bonnet.

With the above configuration, the casing and bonnet are cooled by the fluid flowing through the hollow space between the main jacket and the upper jacket, respectively, so that the structure has heat resistance suitable for installation in pipelines in high-temperature environments or pipelines for high-temperature fluids, even if parts such as gaskets that seal between the casing or bonnet and the valve stem are not made of special heat-resistant materials.

Here, it is desirable that the casing is configured with multiple fins that protrude radially from its outer wall. This allows the casing to be cooled more effectively, further improving the heat resistance of the entire ball valve.

In addition, when providing fins on the outer wall of the casing as described above, drilling holes in the fins increases the surface area of the fins and improves the fluid flow that cools the casing, further increasing the cooling effect of the casing.

As described above, the ball valve of the present invention is designed to have heat resistance suitable for installation in pipelines in high-temperature environments or pipelines for high-temperature fluids by passing a cooling fluid through the hollow space between the casing and the main jacket and the hollow space between the bonnet and the upper jacket. This allows the valve to be manufactured in a short period of time and at lower overall cost than conventional valves that incorporate parts made from special heat-resistant materials.

A longitudinal sectional front view of a ball valve according to an embodiment. 2 is a cross-sectional view taken along line II-II of FIG. FIG. 2 is an enlarged longitudinal sectional front view of a main part on the inlet side of FIG. FIG. 3 is an enlarged longitudinal front view showing only the fin portion of the casing shown in FIG. 5 is a plan view of the fin portion of the casing of FIG. 4 ;

Below, an embodiment of the present invention will be described with reference to the drawings. This ball valve is installed in a pipeline in a high-temperature environment or in a pipeline through which a high-temperature fluid flows, and as shown in Figures 1 and 2, it is equipped with a casing 1 having a valve chamber 1c with an open top between an inlet port 1a and an outlet port 1b, a valve element 2 housed in the valve chamber 1c, a valve shaft 3 that rotates the valve element 2, a bonnet 4 that closes the top of the valve chamber 1c while the valve shaft 3 passes through it, a main jacket 5 that is molded integrally with the casing 1 while covering the periphery of the casing 1, and an upper jacket 6 that is molded integrally with the bonnet 4 while covering the periphery of the bonnet 4.

The casing 1 has flanges 7, 8 for connecting to pipelines at the outer ends of the inlet port 1a and the outlet port 1b. Cylindrical seat rings 9, 10 are fitted into the inner circumferences of the inlet port 1a and the outlet port 1b, so that the inner ends are pressed against the valve body 2.

Here, the pressing mechanism of each seat ring 9, 10 against the valve body 2 will be explained based on Figure 3. Note that Figure 3 only shows the pressing mechanism of the inflow side seat ring 9, but the pressing mechanism of the outflow side seat ring 10 has the same structure as the inflow side.

As shown in Figure 3, part of the outer periphery of the seat ring 9 has a bellows structure, and a flange portion 9b is provided so as to be continuous with the outer end of the bellows portion 9a. The flange portion 9b is pressed against a stepped surface formed on the inner periphery of the inlet port 1a by an annular seat retainer member 13 screwed into the inlet port 1a of the casing 1. A disc spring 12 for preventing the seat retainer member 13 from loosening is supported by a retainer ring 11 screwed into the outer end of the inlet port 1a.

As a result, with the flange portion 9b of the seat ring 9 fixed, the bellows portion 9a expands and contracts to follow the oscillation of the valve body 2, and the inner end is constantly pressed against the valve body 2 with an appropriate pressure. A gasket 14 is incorporated into the recess formed on the inner surface of the flange portion 9b of the seat ring 9 to seal against the stepped surface of the inlet port 1a. The inner end of the outflow side seat ring 10 is pressed against the valve body 2 with the same structure.

The outer wall of the casing 1 is provided with a number of fins 15 as shown in Figure 2. As also shown in Figures 4 and 5, the fins 15 protrude radially from the outer wall of the casing 1 and extend in the vertical direction, and each fin 15 has a number of long holes 15a drilled along the vertical direction. This increases the surface area of each fin 15 and improves the fluidity of the fluid flowing between the casing 1 and the main jacket 5, as described below, allowing the casing 1 to be effectively cooled by the fluid.

The valve body 2 is formed in a ball shape with flat surfaces on the top and bottom, and has a valve hole 2a that penetrates horizontally through its center. An oval-shaped protrusion on the upper flat surface of the body, seen from above, is connected to the lower end of the valve shaft 3 so as not to rotate relative to the valve shaft 3, and a cylindrical protrusion on the lower flat surface is rotatably inserted into a recess that forms the bottom side of the valve chamber 1c of the casing 1. As a result, the valve body 2 rotates together with the valve shaft 3 between an open position where the valve hole 2a of the body communicates with the inlet port 1a and outlet port 1b of the casing 1, and the inlet and outlet seat rings 9, 10 are pressed against the outer peripheral surface of the periphery of the valve hole 2a, and a closed position that is at an angle of 90 degrees from the open position.

The outer peripheral surface of the main body of the valve body 2, excluding the upper and lower flat surfaces, is formed so that the spherical curvature of the portion facing the inlet port 1a and outlet port 1b in the closed valve position is greater than the spherical curvature of the other portions. This reduces the frictional resistance of the seat rings 9 and 10 pressed against the outer peripheral surface of the main body, compared to when the outer peripheral surface of the main body, excluding the flat portions, is formed as a sphere with a constant curvature, allowing the valve body 2 to rotate smoothly and reducing wear on the seat rings 9 and 10.

The valve shaft 3 has an oval-shaped engagement hole at its lower end, which is formed with a larger diameter than its central portion, and the upper protrusion of the valve body 2 fits into this engagement hole, connecting it to the valve body 2 so that it cannot rotate relative to it. The upper end of the valve shaft 3 protrudes upward through an annular packing retainer 17 that is bolted to the upper end of the bonnet 4, sealed by a packing 16 installed in a recess (packing box) on the inner periphery of the bonnet 4. A handle (not shown) is attached to the protruding part of the valve shaft 3, and the valve body 2 rotates together with the valve shaft 3 to open and close.

The bonnet 4 is integrated with the casing 1 via a gasket 18 by multiple bolts (not shown), with its lower end fitting into the inner circumference of the cylindrical portion in the center of the casing 1 and blocking the upper part of the valve chamber 1c of the casing 1.

The main jacket 5 is composed of a cylindrical portion 5a that covers the periphery of the casing 1, an inlet 5b and an outlet 5c that extend horizontally in opposite directions from the side wall of the cylindrical portion 5a, and an outlet 5d for maintenance that extends downward from the bottom wall of the cylindrical portion 5a. The cylindrical portion 5a is molded integrally with the casing 1 in a state in which the inlet port 1a and the outlet port 1b of the casing 1 are passed through. The inlet 5b is located above the outlet 5c, so that the fluid flows smoothly from the inlet 5b to the outlet 5c. The inlet 5b, the outlet 5c, and the outlet 5d are each provided with flanges 19, 20, and 21 for connection to an external pipeline.

Under normal circumstances, the exhaust port 5d of the main jacket 5 is closed, and fluid that flows from the external pipeline through the inlet 5b into the hollow portion 22 between the cylindrical portion 5a and the casing 1 cools the casing 1 and flows out from the outlet 5c to the external pipeline. During maintenance, the exhaust port 5d is opened and fluid that has accumulated in the lower portion of the hollow portion 22 between the cylindrical portion 5a and the casing 1 is discharged from the exhaust port 5d, and work is carried out in this state.

The upper jacket 6 is composed of a cylindrical portion 6a that covers the bonnet 4, and an inlet 6b and an outlet 6c that extend horizontally in opposite directions from the side wall of the cylindrical portion 6a. The cylindrical portion 6a is integrally molded with the bonnet 4, connecting it to the upper and lower ends of the bonnet 4. The inlet 6b is located above the outlet 6c, allowing fluid to flow smoothly from the inlet 6b to the outlet 6c. The inlet 6b and the outlet 6c are provided with flanges 23 and 24, respectively, for connection to external pipelines. The fluid that flows from the external pipeline through the inlet 6b into the hollow portion 25 between the cylindrical portion 6a and the bonnet 4 cools the bonnet 4 and flows out from the outlet 6c to the external pipeline.

This ball valve has the above-mentioned configuration, and the casing 1 and bonnet 4 are cooled by the fluid flowing through the hollows 22, 25 between the main jacket 5 and the upper jacket 6, respectively. Furthermore, fins 15 with long holes 15a are provided radially on the outer wall of the casing 1 to enhance the cooling effect of the casing 1. This provides heat resistance suitable for installation in pipelines in high-temperature environments or pipelines for high-temperature fluids, even without making the entire casing 1 or parts such as the packing 16 that seals between the bonnet 4 and the valve stem 3 out of special heat-resistant materials. Therefore, the cost of the entire valve can be reduced and it can be manufactured in a short period of time, compared to conventional valves that incorporate parts made of special heat-resistant materials.

The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is indicated by the claims rather than the above description, and it is intended to include all modifications within the meaning and scope of the claims.

For example, in the embodiment, the main jacket and the upper jacket are molded integrally with the casing and the bonnet, respectively, but they may be formed separately from the casing and the bonnet and integrated with each other using bolts, etc.

The shape of the fins on the outer wall of the casing and the number and shape of the holes in the fins can be selected in a variety of ways, not limited to those described in the embodiment, and the holes in the fins can be omitted for cost reasons.

1 Casing 1a Inlet port 1b Outlet port 1c Valve chamber 2 Valve body 2a Valve hole 3 Valve stem 4 Bonnet 5 Body jacket 6 Upper jacket 15 Fin 15a Long hole 22 Hollow portion 25 Hollow portion

Claims (3)

A ball valve comprising: a casing having a valve chamber with an open top between an inlet port and an outlet port; a ball-shaped valve body housed in the valve chamber; a valve stem for rotating the valve body; and a bonnet for passing the valve stem through the bonnet and closing the top of the valve chamber,
A ball valve characterized in that it is provided with a main jacket covering the periphery of the casing and an upper jacket covering the periphery of the bonnet, and a fluid for cooling the casing is flowed through a hollow space between the main jacket and the casing, and a fluid for cooling the bonnet is flowed through a hollow space between the upper jacket and the bonnet. The ball valve according to claim 1, characterized in that the casing has multiple fins protruding radially from its outer wall. The ball valve according to claim 2, characterized in that the fins are perforated.

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