JP2594707Y2 - Valve seal seal - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shaft sealing gasket for sealing a stem for a gate valve, a globe valve and other valves, and in particular, to improve sealing without increasing frictional resistance when operating the stem. The present invention relates to a shaft sealing gasket for a valve.

[0002]

2. Description of the Related Art When an internal fluid to be sealed is a liquid, it can be sealed relatively easily by a conventional packing and packing combination. It has been difficult to completely seal the gap between the shaft and the contact surface between the packing and the stuffing box, and a small leak easily occurs through a minute space inside the packing.

The partial cross-sectional view shown in FIG. 3 shows an example of a conventional packing and packing combination used for valves such as gate valves and globe valves in order to prevent the above-mentioned minute leakage. 21 is a bonnet fixed to the upper part of the valve body, 22 is a stem for opening and closing a valve element provided in the body, 23 is a back bush,
Reference numeral 24 denotes a lantern ring, reference numerals 25 and 26 denote packing rings, and reference numeral 27 denotes a gland for performing a tightening action.

A back bush 23 is screwed and fixed below the stem hole 21a of the bonnet 21, and the stem 22 above the back bush 23 of the stem hole 21a is fixed.
Is a stuffing box 21b, which is filled with packing rings 25 and 26 and a lantern ring 24 as shown in the figure, and presses the gland 27 from above to seal the gap between the bonnet 21 and the stem 22. It has become. In this example, the packing ring 25 is a packing ring formed by compressing expanded graphite, and the packing ring 26 is a packing ring formed by weaving graphite fibers.

[0005] A screw hole 21c is provided from the outside of the bonnet 21 at a position substantially in the middle of the length of the stuffing box 21b, and a grease nipple is screwed into the screw hole 21c to inject grease. The injected grease fills the gap between the inner periphery of the lantern ring 24 and the stem 22 and the gap between the outer periphery and the bonnet 21 to prevent leakage of the fluid inside the valve.

[0006]

In the structure as shown in FIG. 3, machining of the screw hole 21c is troublesome, there is no effect unless the injection of grease is reliable, and the sealing cannot be performed due to deterioration or loss of the grease. Since it sometimes becomes complete, it has problems such as frequent maintenance and inspection. In addition, in order to prevent micro leakage, a method using a bellows is also used in addition to the structure shown in FIG. 3, but the structure is complicated or expensive, and each has a problem. The present invention has been developed in view of the above-mentioned conventional problems. The sliding resistance of the stem is small, the operability is excellent, the micro leakage is reliably prevented, and the structure is simple and relatively inexpensive. It is an object of the present invention to provide a valve seal packing for a valve which has high performance and requires little maintenance.

[0007]

SUMMARY OF THE INVENTION To achieve the above object, the present invention provides a rubber cylindrical bush in which the inner diameter is slidably contacted with a valve stem, and the outer diameter of the bush is connected to the valve. It is closely in stuffing box, to form a multistage annular projection the inner diameter of this bush and a seal between the stem to close the annular projection on the outer peripheral surface of the stem co
In addition, multi-stage annular projections were also formed on the outer diameter portion of the bush . In this case, the annular projection on the outer diameter of the bush
It is preferable that the annular projection is formed smaller than the annular projection at the inner diameter portion, and that the annular projection is in close contact with the inner peripheral surface of the stuffing box to seal between the stuffing box and the bush is made of metal or synthetic resin. preferred for integrally formed by coating a rubber entire outer peripheral surface of the cylindrical core formed of a rigid member
New Furthermore, expanded graphite, asbestos, graphite fibers, synthetic fibers such as conventional packing ring and is good to the packing combination in combination with the packing of the present invention formed by.

[0008]

In the shaft seal packing according to the present invention, a small leak that cannot be sealed by the conventional packing ring and leaks is formed between the stem and the stem. Sealed closely to the surface. Since the annular projection has rubber elasticity, it is securely in close contact with the entire periphery of the stem, and the sealing is completed because the sealing is performed in multiple stages by the multiple annular projections. In addition, the annular projection formed on the outer diameter portion of the packing of the present invention is in close contact with the inner peripheral surface of the stuffing box, and also performs complete sealing. In this case, the annular projection of the outer diameter portion of the bush is formed smaller than the annular projection of the inner diameter portion of the bush described above. In addition, the surface pressure increases against the inner surface of the stuffing box, increasing the sealing function,
Furthermore, the sealing effect can be further increased by filling the space formed in the annular projection of the outer diameter portion and the inner surface of the stuffing box with oils and fats. On the other hand, the annular projection on the inner diameter portion has a function of reducing the resistance when the stem slides in addition to the function of the annular projection on the outer diameter portion.

Further, since the packing of the present invention is formed by covering the entire outer peripheral surface of the cylindrical core material of metal or synthetic resin with rubber, it is necessary to compress the packing ring mounted inside the packing of the present invention. Even when pressed by the ground, the packing ring hardly deforms, and the inner packing ring can be reliably compressed. Also, this core material backs up the annular projections of the inner and outer diameter portions, and ensures that the annular projections are in close contact with the outer peripheral surface of the stem and the inner peripheral surface of the staffin box.

Since only the annular projection is in contact with the stem of the packing of the present invention, the frictional resistance against the rotation and reciprocation of the stem is extremely small. Further, the shape of the stuffing box for mounting the packing of the present invention may be the same as that of mounting the conventional packing ring, and does not require processing to be performed from the outside of the bonnet such as a screw hole for injecting grease.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing an embodiment of a valve seal packing for a valve according to the present invention. In FIG. 1, 1
Is a bonnet of a valve such as a gate valve or a globe valve. The bonnet 1 is fixed to an upper portion of a body (not shown), and a valve body such as a disc is housed in the body so as to be freely opened and closed. Reference numeral 2 denotes a stem, and the valve is opened and closed by operating the stem 2. 3 is a back bush, 4 is a bush described later, 5 and 6 are packing rings, 7 is a ground, 8 is a ground flange, 9 is a ground bolt, 10 is a ground bolt nut, and 11 is a ground bolt pin.

A back bush 3 is screwed below the stem hole 1a of the bonnet 1 and fixed.
a between the stem 2 above the back bush 3 is a stuffing box 1b, which is packed with packing rings 5 and 6 and a bush 4 as shown in FIG. Is pressed down by a gland bolt 9 and a gland nut 10 via a gland flange 8, and seals between the bonnet 1 and the stem 2 by the packing rings 5 and 6 and the bush 4. I have. In this example, the packing ring 5 is a packing ring formed by compressing expanded graphite, and the packing ring 6 is a packing ring formed by weaving graphite fibers.

The bush 4 has a rubber core 4a on the entire outer peripheral surface of a cylindrical core member 4a formed of a rigid member such as metal or synthetic resin.
And a multi-stage annular projections 4c and 4d on the inner and outer diameters, respectively.
Is formed, and the annular projection 4c is in close contact with the outer peripheral surface of the stem 2 so as to seal the space between the stem 2 and the stem 2.
The annular projection 4d is in close contact with the inner peripheral surface of the stuffing box 1b to seal the space between the stuffing box 1b. Further, an annular projection 4d on the outer diameter of the bush 4
Are formed smaller than the annular projection 4c of the bush inner diameter portion to increase the sealing function and reduce the sliding resistance of the inner diameter portion.

Next, the operation of the embodiment shown in FIG. 1 will be described. In the packing rings 5 and 6, as described above, leakage cannot be completely stopped, and a minute leakage often occurs. This small leakage, by the annular projection 4 c in between the stem 2, stuffing box 1b
In between it is sealed by the annular projection 4 d. The annular projection 4 c and 4 d, because it has the elasticity of rubber, is backed up by heart <br/> material 4a, ensures close contact with the inner peripheral surface of the outer peripheral surface and the stuffing box 1b of the stem 2 Along with
The annular projection 4 c and 4 d are provided in multiple stages sealing in multiple stages is performed, the sealing is ensured. Since the annular projection 4d on the outer diameter of the bush 4 is formed smaller than the annular projection 4c on the inner diameter of the bush, the bush 4 has a function of tightening the bush 4 into the stuffing box 1b to reduce the insertion load at the time of insertion. In addition, the surface pressure on the inner surface of the stuffing box 1b is increased, and the sealing function can be increased. The sealing effect can be further increased by filling the space 4e formed on the inner surface of the annular projection 4d of the outer diameter portion and the stuffing box 1b with oils and fats. On the other hand, the annular projection 4c of the inner diameter portion has a function of reducing the resistance when the stem 2 slides. Further, since there is no space in the packing 4 itself, the packing 4 does not leak through the packing.

Further, even if the gland bolts and nuts 10 and 11 are tightened to compress the packing rings 5 and 6, and the bush 4 is pushed by the gland 7, the bush 4 is reinforced by the metal cylindrical core 4a. As a result, the packing rings 5 and 6 can be reliably compressed with little deformation. Furthermore, bush 4
Since only the annular projection 4c is in contact with the stem 2, the frictional resistance against rotation and reciprocation of the stem 2 is extremely small. The shape of the stuffing box 1b for mounting the bush 4 may be the same as that for mounting the conventional packing ring, and does not require a process to be performed from the outside of the bonnet 1 such as a screw hole for injecting grease. FIG.
FIG. 3 shows another embodiment of the present invention, in which the same parts as those in FIG. This is an example in which the bush 4 in FIG. 1 is applied as a ground, and a contact portion 4f that comes into contact with the ground flange 8 is formed at the upper end of the core material 4a. The bush 4 exhibits the same function as the bush 4 of FIG. 1 together with the original ground function. The packing and the packing combination of the present invention are not limited to the use of the valve and the gas fluid, but can be used for other purposes such as filling the packing in the stuffing box and sealing the shaft.

[0016]

[Effect of the Invention] As is clear from the above, according to the present invention , the multi-stage annular projection is provided inside and outside the bush.
The shaft seal can be securely performed, the structure is simple, and it can be packed in a stuffing box of the same shape as the stuffing box used for the conventional packing ring, and used in combination with the conventional packing ring be able to.
In addition , the frictional resistance with the shaft is small, frequent maintenance and inspection are not required, and the reliability is high and the economy is excellent. Further
Is the annular protrusion on the outer diameter of the bush,
Since the bush is smaller than the annular projection,
Insertion load is reduced when the interference fit is inserted into the fin box
And has a function to fit the inner surface of the stuffing box.
Surface pressure increases and the sealing function can be increased.
Wear.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view showing one embodiment of a shaft seal packing of a valve according to the present invention.

FIG. 2 is a partial cross-sectional view showing another embodiment of the valve shaft packing of the present invention.

FIG. 3 is a partial sectional view showing an example of a conventional packing and packing combination.

[Explanation of symbols]

 1b Staffing box 2 Stem (shaft) 4 Bush 4a Core 4b Rubber 4c, 4d Annular protrusion 5, 6 Packing ring

Claims (3)

(57) [Scope of request for utility model registration] 1. A inner diameter portion of the rubber cylindrical bush is in sliding contact with the stem valve and of the bush outer diameter is closely in stuffing boxes of the valve, the multi-stage inside diameter portion of this bush to form a cyclic projection and a seal between the stem to close the annular projection on the outer peripheral surface of the stem co
A multi-stage annular projection is also formed on the outer diameter portion of the bush . 2. An annular projection on the outer diameter of the bush is provided with a bushing.
It is formed smaller than the annular projection of the inside diameter portion of the Interview, shaft sealing valves 請 Motomeko 1 wherein so as to seal between the annular projection is in close contact with the inner circumferential surface of the stuffing box stuffing box Packing. Wherein said bushing is a metal or coated with rubber in all the outer peripheral surface of the cylindrical core formed of a rigid member such as a synthetic resin Ru der those formed integrally 請 Motomeko 1 or 2 Description
Sealing packing for valve.