JPS628693Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a shaft sealing device for a seat ring of a chimney-shaped valve.

Conventionally, it has been known to insert a reinforcing core inside the seat ring of a butterfly valve, and these have the structure shown in Fig. 1 or 2, and the core used is made of synthetic resin. There are two types: solid and metal. However, the conventional method had the following drawbacks. That is, the structure shown in Fig. 1 uses a resin core 1, but since the resin core may be damaged by the pressure during rubber vulcanization, the entire core is covered with rubber as shown in Fig. 2. It cannot be covered with Most shaft seal structures using a resin core have a structure in which a portion of the rubber portion at the bottom of the core protrudes, and the protrusion is brought into pressure contact with the valve stem 3 to seal the shaft. However, with this structure, when inserting the valve stem, there is a risk that notches and cuts may occur, making shaft sealing impossible. If the protrusion is damaged, the seat ring 4 itself must be replaced. Therefore, it is possible to insert an O-ring groove by machining an O-ring groove inside the resin core, but if a leak occurs in the primary seal 5 of the cut part, the liquid will come into contact with the resin core, so it is corrosive. There are problems with fluids that make them unusable. Furthermore, since the resin core needs to be molded with a mold, it is inevitable that the mold cost will increase the cost, making it unsuitable for small-scale production.

Figure 2 shows a structure in which a metal core 1 is inserted inside a seat ring 4 and the core is completely covered with rubber, and the shaft seal is formed by a protrusion 2 similar to that in Figure 1.
In many cases, it is done by Therefore, the device shown in FIG. 2 also has the same drawbacks as the device shown in FIG.

The one shown in FIG. 3 has a metal O-ring case 6 inside the seat ring 4.
It does not have a reinforcing core. Therefore, the structure shown in FIG. 3 only has the function of making the shaft seal with the rotating shaft more reliable through the self-aligning action, and it is not possible to reinforce the seat ring. Can not.

This invention was made to eliminate such drawbacks seen in the conventional ones, and it completely seals the pair of shaft holes passing through the seat ring and the valve stem passing through these shaft holes with low frictional force. The technical problem is to make it possible to do so while also preventing fluid from coming into contact with the metal core inside the seat ring.

The technical means provided by the present invention to solve such technical problems is a valve stem insertion shaft hole that is pierced in the radial direction of the seat ring 10 that is attached to the inner circumferential surface of the main body 11 of the chimney valve. In a shaft sealing device for a seat ring of a chiral valve, in which a metal O-ring case 13 for housing an O-ring 16 that is in close contact with the outer circumferential surface of the valve stem is buried in the shaft hole 12 in the O-ring case 13. A cylindrical part 15 extending along the axial direction of the cylindrical part 15 is arranged in series, and a part of the shaft hole 12 is formed by the inner circumferential surface of the cylindrical part 15. This is because the core 17 made of aluminum is buried.

The above technical means works as follows. In other words, since the O-ring case forms part of the shaft hole, it acts as a bearing for the valve stem, preventing galling and deformation of the valve stem, and also prevents the valve stem from galling or deforming. A shaft seal with low frictional force can be achieved, and since the metal core is located outside the O-ring case and inserted into the seat ring, even if the primary seal leaks, the metal core will not leak. There is no risk of contact with fluid, and the O-ring case and metal core can be vulcanized and molded at the same time as rubber vulcanization.

Next, a specific example of the above technical means will be explained with reference to the drawings. In FIGS. 4 to 6, reference numeral 10 denotes a seat ring fixed to the body 11 of the butterfly valve, through which a shaft hole 12 into which a valve stem is inserted is inserted at a symmetrical position. Reference numeral 13 denotes an O-ring case inserted into the seat ring 10, and has an O-ring groove 14 and a cylindrical portion 15 forming a part of the shaft hole 12. The O-ring case 13 is made of corrosion-resistant material such as stainless steel or copper alloy. The O-ring groove 14 may have a cross-sectional shape as shown in FIG. 4, or may have a cross-sectional shape as shown in FIG. In either structure, when the O-ring 16 is inserted, a space remains, so a lubricant can be sealed in the space to improve the lubrication effect of the valve stem.

A metal core 17 is located outside the O-ring case 13 and inserted into the seat ring 10, as shown in FIGS. In this way, the metal core 17 is completely covered by the rubber of the seat ring 10 and the O-ring case 13, so even if fluid leaks from the primary seal, there is no risk of the metal core coming into contact with the liquid. It is possible to use general inexpensive structural steel materials instead of rustless steel materials, and it is possible to reduce costs.

The O-ring case 13 and the metal core 17 can be vulcanized and formed at the same time when the seat ring 10 is vulcanized to be integrated with the seat ring 10. Therefore, since the adhesive area with the rubber is large, the adhesive force between the O-ring case and the seat ring becomes large, and the strength can be improved.

Next, the unique effects of this invention will be explained.

(1) Even if the primary seal leaks, fluid will not come into contact with the metal core, so the core can be made of ordinary, inexpensive structural steel, reducing costs.

(2) Since the O-ring groove of the O-ring case is cross-sectional or square-shaped, lubricant can be filled in the remaining space where the O-ring is inserted to improve the lubrication effect.

(3) Since the O-ring case has a cylindrical part that is continuous with the O-ring groove and forms part of the shaft hole, the cylindrical part acts as a bearing for the valve stem and prevents the valve stem from galling and In addition to preventing deformation, the compression margin of the rubber in the direction of the cut portion of the seat ring can be made uniform, and the sealing performance and durability of the primary seal can be improved. Moreover, since the bonding area between the O-ring case and the rubber increases, the bonding force between the O-ring case and the seat ring increases, resulting in improved strength.

(4) O-ring The O-ring inside the case can almost completely prevent external leakage, and since the O-ring is a separate part, it can be easily replaced if it wears out.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a conventionally known butterfly valve with a seat ring having a resin core, Fig. 2 is a sectional view of a part of a known seat ring having a metal core, and Fig. 3 is an O-ring case. A known cross-sectional view, FIG. 4 is a cross-sectional view of the main part according to this invention, and FIG.
The figure is a view similar to FIG. 4 showing a modification, and FIG. 6 is a cross-sectional view of FIG. 5 taken in a different direction. 10...Seat ring, 11...Main body, 12...
... Shaft hole, 13 ... O-ring case, 14 ... O-ring groove, 15 ... Cylindrical part, 16 ... O-ring, 1
7...Metal core.

Claims (1)

[Scope of utility model registration request] A metal valve that accommodates an O-ring 16 that fits closely to the outer circumferential surface of the valve stem in the valve stem insertion shaft hole 12 that is pierced in the radial direction of the seat ring 10 that is attached to the inner circumferential surface of the main body 11 of the chimney-shaped valve. In the shaft sealing device for a seat ring of a chiral valve in which an O-ring case 13 is embedded, a cylindrical portion 15 extending along the axial direction of the shaft hole 12 is connected to the O-ring case 13, and the shaft hole 1
A shaft sealing device characterized in that a part of the shaft seal 17 is formed by the inner circumferential surface of the cylindrical portion 15, and a metal core 17 is embedded outside the O-ring case 13 and inside the seat ring 10.