JPS6027868B2 - butterfly valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides gland packing portions for preventing leakage to the outside between both ends of a valve shank and a cylindrical portion on the valve body side for passing them separately, The present invention relates to a butterfly valve in which a bearing portion for the valve stem is provided on the outside of each of the gland packing portions.

This type of butterfly valve is suitable for use in high-temperature, high-pressure fluid transport paths such as combustion exhaust gas, but there is a problem of competition due to the transport fluid, and conventionally, the bearing part for the valve stem is generally ground packed. It is installed on the outside of the section.

However, the distance between the two bearings is long, and when the valve body is fully opened, the valve body protrudes significantly due to the fluid pressure applied to the valve body, resulting in a problem of seal failure.

Therefore, it has been considered to make the valve shank larger in diameter to reduce the amount of flow, but this has the disadvantage that the flow path opening area when fully opened is 4 mm, which deteriorates the flow characteristics. In view of the above points, the present invention has been developed to prevent sealing defects caused by sagging deformation and sagging deformation caused by fluid pressure, while avoiding phosphorization on the bearing portion and without increasing the diameter of the valve stem. The aim is to be able to suppress it.

The characteristic configuration of the butterfly valve of the present invention is that gland packing portions are provided between both ends of the valve shank and the cylindrical portion on the valve box side for passing them separately to prevent leakage to the outside. A butterfly valve is provided with a bearing portion for the valve shaft on the outside of each gland packing portion, wherein each of the gland packing portions is configured to be divided in the longitudinal direction of the valve shank, and between each of the divided gland packing portions, The flat bearing is iron-mounted to the valve shaft and the valve box side cylindrical portion. Therefore, the following effects are achieved.

■...Since flat bearings are iron-mounted on the valve shank part further inside the bearing parts on both ends of the valve stem, the distance between the bearing parts with respect to the valve stem can be further reduced by 4 cm. Suppresses the deformation of bent twill.

■...Since a plain bearing is located between each segment of the gland packing, even if the valve stem extends and the segmented gland packing on one side is pressed and a seal failure occurs, the plain bearing will not be removed. Due to the seesaw phenomenon using the fulcrum, the split gland packing on the other side securely seals and maintains a good sealing effect.

■...Since the bearings on both ends of the valve shank are located outside the gland packing part, it is possible to avoid distortion caused by the fluid in the bearing part, but the bearing member is made of plain bearings to suppress the sagging deformation of the valve shank. Moreover, by interposing the gland packing between the divided gland packings, the narrow gap between the valve shank and the valve box side cylindrical part provides effective heat shielding.

Therefore, the following effects can be obtained.

■ It is possible to suppress the bending deformation of the valve stem caused by fluid pressure and the sealing failure of the gland packing part due to manipulation deformation, and it is possible to improve the flow characteristics.

@ The flat bearing interposed between the split gland packing parts effectively maintains sealing performance, and the good sealing performance provides a synergistic effect in that it provides good heat insulation for the flat bearing and the bearings on both ends of the valve shank. This action prevents the bearing from becoming rusty. ■ By using a plain bearing as the bearing interposed between the split gland packing parts, even if the conventional valve body side cylindrical part is used as is, it can be used in the narrow gap between the valve stem and the valve body side cylindrical part. However, it can be equipped with iron, does not require major design changes, and can be manufactured at low cost.

Next, embodiments of the present invention will be described in detail based on the drawings.

A hollow cylindrical valve shank 1 is rotated via bearing parts 4, 4 with its both ends inserted into valve body side cylindrical parts 3, 3 formed in a valve body 2, respectively. A valve opening/closing mechanism 5 is interlocked with one end of the valve stem 1, and as the valve body 6 rotates, a seat 7 attached to the circumferential surface of the valve body 6 is moved around the inner circumference of the valve body 2. It is configured to be closely and spaced apart from the seat 8 provided on the surface, and is located between the valve stem 1 and the valve body side cylindrical parts 3, 3, respectively, and closer to the valve element 6 than the bearing parts 4, 4, respectively. In addition to providing gland packing parts 9, 9, a flow path R for passing a purge fluid such as steam is formed further on the valve body 6 side. A butterfly valve is constructed that is suitable for application to a transportation route for gas containing dust at high temperature and high pressure, such as exhaust gas generated when regenerating silica sand (Si02) or the like.

The gland packing parts 9, 9 are each divided in the longitudinal direction of the valve shank 1, and a flat bearing 10 is iron-mounted between the divided gland packing parts 9a, 9b, and the valve stem 1 is connected to the valve body 2. However, it is configured to be supported at four points: both bearing parts 4, 4 and both flat bearings 10, 10. Fillings 11, 11 such as stellite are provided by welding at the portions of the plain bearings 10, 10 that come into sliding contact with the valve stem 1, and the portions of the valve stem 1 corresponding to the plain bearings 10, 10, respectively, and
The grease supply path R2 is connected through the valve box side cylindrical part 3, and the annular grooves 12, 13 and both grooves 12, 13 formed on the inner and outer peripheral surfaces of the plain bearing 10 are connected to each other. The valve stem 1 is inserted through through holes 14 bored at four locations in the circumferential direction.
It is configured to supply grease to the sliding contact points between the valve stem 1 and the flat bearings 10, 10, and is configured to prevent seizure between the valve stem 1 and the flat bearings 10, 10, respectively, and to improve the sealing performance of the gland packing parts 9, 9. has been done.

In order to supply the purge fluid, an annular groove 1 is provided on each of the inner and outer circumferential surfaces.
A purge ring 18 is formed by drilling holes 5 and 16 and has through holes 17 at six locations in the circumferential direction for passing through the valve body side cylindrical portion 3 and the valve stem 1. Between,
Provided to communicate the outer circumferential groove 16 and the flow separation R,
The purge fluid is supplied to the valve body 2 through the flow path R formed by the gap between the valve stem 1 and the collar 19 provided to guide the valve stem 1, and the bush 20 which is internally drummed to protect the valve body side cylindrical portion 3. Gland packing part 9 and plain bearing 10
It is constructed to prevent the ingress of dust to the side and to provide heat insulation from the transport fluid.

Inside the valve shaft 1, one end thereof is used as an inlet 21, and the pond end thereof is used as an outlet 22, so that cooling air is allowed to flow, thereby cooling the valve rod 1. Next, the correlation between the load on the valve shank 1 and the amount of sag in the butterfly valve will be explained in comparison with a conventional butterfly valve in which the valve stem 1 is supported only by the two bearing parts 4, 4.

That is, as shown in Fig. 3, in the subordinate butterfly valve,
The amount of sagging deformation of the valve stem 1 increases at a large rate of change in proportion to the load applied to the valve body 6, but in the butterfly valve according to the present invention, the amount of deflection deformation of the valve stem 1 increases at a large rate of change in proportion to the load applied to the valve body 6. Although the amount of manipulated deformation of the valve shank 1 increases at the rate of change, as a result of the flat bearings 10 and 1 being subjected to bearings, the shank deformation of the valve shank 1 increases during the bearing action. The amount is increased at a small rate of change (approximately 1/8 compared to the conventional one) in proportion to the load, and the amount of deformation of the valve stem 1 due to manipulation can be significantly suppressed.

[Brief explanation of the drawing]

The drawings show an embodiment of the butterfly valve according to the present invention, and the first
The figure is a partially cutaway view, FIG. 2 is an enlarged vertical cross-sectional view of the main part, and FIG. 3 is a graph showing the correlation between the load on the valve shank and the amount of shank deformation. 1... Valve head, 3... Valve box side cylindrical part, 4
...Bearing part, 9...Gland packing part, 9
a, 9b...Divided ground packing section, 10.
...Flat bearing, 11...Filling metal, R2...
・Grease supply route. Diagram N Ship

Claims (1)

[Claims] 1. Gland packing portions 9 are provided between both ends of the valve stem 1 and the valve body side cylindrical portions 3, 3 for passing the valve stems separately, to prevent leakage to the outside. The butterfly valve is provided with a bearing part 4 for the valve stem 1 on the outside of each of the gland packing parts 9, and each of the gland packing parts 9 is divided in the longitudinal direction of the valve stem 1. At the same time, the divided gland packing portion 9a,
A butterfly valve in which a flat bearing 10 is fitted to the valve stem 1 and the valve box side cylindrical part 3 in each of the sections 9b. 2. A metal plate 11 is placed at the sliding contact point between the plain bearing 10 and the valve stem 1.
11. A butterfly valve according to claim 1, comprising: 11. 3. The butterfly valve according to claim 1 or 2, wherein a path R_2 is formed to supply grease to the sliding contact portion of the plain bearing 10 with respect to the valve stem 1 and the valve body side cylindrical portion 3. .