JPS6147355B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a shaft sealing device, particularly a shaft sealing device using a V-shaped packing.

In general, a typical use of a shaft sealing device using a V-shaped packing is to install a plurality of V-type packings in a shaft sealing chamber formed between a shaft 1 and a gland box 2, as shown in FIG.
A mold seal 3 is clamped and mounted between a male adapter 4 and a female adapter 5, and then tightened with a seal presser 6. Such shaft sealing devices are mainly used for low and medium pressures. In addition, a typical example for high pressure is as shown in FIG.
A plurality of mold seals 3 and metal spacer rings 7 are each inserted alternately, a male adapter 4 and a female adapter 5 are sandwiched and attached, and the seal presser 6 is used to tighten them. When a V-shaped packing 3 is used in such a shaft sealing device, it is often necessary to cut one place on the circumference to provide a cutting point 8 as shown in FIG. This is because it is often inconvenient to attach and remove the V-shaped gasket 3 depending on the shaft-sealing chamber of the device, so a cutting point is provided for convenience. In this case, the respective V-shaped gaskets 3 are installed in a shifted manner so that the positions of the cut points 8 do not coincide with each other. However, fluid tends to leak along the cut points 8 of the V-shaped packing 3, and the sealing effect is lower than that of the V-shaped packing 3 without the cut points 8.

However, as shown in FIG. 1, a gap chamber A is often provided between each V-shaped packing 3, and this is used to relieve the stress of the V-shaped packing 3 itself tightened by the packing presser 6, and to reduce the stress of the V-shaped packing 3. Such a structure is often adopted in order to provide an interference margin to enable additional tightening using the seal retainer 6 in order to recover the deterioration in sealing performance due to wear and tear of the seal 3. In the case of such a structure, it was certain that fluid would leak out along the cut point 8 of the V-shaped packing 3. Further, as shown in FIG. 2, there is a gap B between the V-shaped packing 3 and the metal spacer ring 7, and a gap between the inner and outer peripheral surfaces of the metal spacer ring 7 and the inner peripheral surface of the gland box 2 or the shaft 1.
V
It was also certain that fluid would leak out along the cut point 8 of the mold seal 3.

The present invention is a shaft sealing device that has been developed to eliminate these conventional drawbacks.The sealing member, such as a V-shaped packing, is provided with a cut point for convenient installation and removal, and the number of V-shaped packings is increased. Although it has a structure that allows tightening, it is designed to exhibit a sealing effect similar to or better than that of using an endless gasket.

That is, in the present invention, a convex abdominal part of an annular packing having a V-shaped cross section and having one cut point on the circumference;
A concave back surface of an annular secondary packing having a V-shaped cross section and having one cut point on the circumference is brought into close contact with the cut points at staggered positions to form a pair of sealing members, and this sealing member The angle θ ₁ of the V portion of the concave back surface portion with a V-shaped cross section and the angle θ ₂ of the V portion of the convex ventral surface portion with a V-shaped cross section are both obtuse angles, and θ
This shaft sealing device is characterized in that a plurality of the sealing members having the relationship of ₂ > θ ₁ are mounted in a shaft sealing chamber.

Hereinafter, one embodiment of the shaft sealing device according to the present invention will be described in the fourth embodiment.
This will be explained based on the figure and FIG.

In Fig. 4, 9 is a V-shaped gasket, and 1
0 is a V-shaped secondary packing, and as shown in FIG. 5, each packing has cutting points 9a and 10a. The convex abdominal part 11 of this V-shaped packing 9 and the concave back part 1 of the V-shaped secondary packing 10
By forming these both surfaces into the same shape so that the two can be brought into close contact with each other, the sealing member 13 is formed by a pair of two types of V-shaped packings as shown in FIG. In this case, each cut point 9a of the V-shaped packing 9 and the V-shaped secondary packing 10,
10a is not placed in the same place, but is placed in close contact at a shifted position. As shown in FIG. 5, the sealing member 13 configured as a pair has a V-portion angle θ ₁ of the concave back portion 14 with a V-shaped cross section and a convex ventral surface portion 15 with a V-shaped cross section. The angle θ ₂ of the V section is an obtuse angle, and by setting the angles to be different and having the relationship θ ₂ > θ ₁ , when a plurality of the sealing members 13 are installed in the shaft sealing chamber, the sealing can be achieved. The structure is such that a gap chamber D can be formed between the members 13, 13 as shown in FIG.
This shaft sealing device includes a plurality of such sealing members 13 installed in a shaft sealing chamber formed by the shaft 1 and the gland box 2.

With such a configuration, the fluid that tends to leak along the cut points 9a and 10a is formed by the convex belly surface 11 of the V-shaped packing 9 and the concave back surface 12 of the V-shaped secondary packing 10. Reliably blocked by the contact surface. Therefore, for example, as shown in FIG. 4, it is possible to provide a retightening function that is essential for this type of shaft sealing device. That is, by forming a gap chamber D between the sealing member 13 and the sealing member 13 that are tightened by the packing presser 6 to provide a tightening margin, retightening is possible, and a seal that lasts for a long time can be achieved. The effect can also be fully demonstrated. In addition, in the embodiment, the V-shaped packing 9
Although the V-shaped secondary packing 10 is made of fluororesin, it may also be made of synthetic resin such as nylon or rubber compounded with reinforcing fibers.In short, the convex abdominal part 11 and the concave back part Any flexible material can be used as long as it forms a contact surface with 12 and can seal the shaft 1 and gland box 2 at the V-shaped edge (rip part) of the packing.

Experimental Example In order to confirm the sealing performance of the product of the present invention, an experiment was conducted with the following specifications.

The experimental conditions were: temperature: room temperature, sealing fluid: fresh water, pressure: increasing in steps of 5 kgf/cm ² in the range of 0 to 30 kgf/cm ² , shaft diameter: φ50 mm, casing inner diameter: φ64 mm,
Number of V-rings: Inventive product 4 settling rings, comparative product 8
Ring, sample: As a product of the present invention, the sealing member shown in Fig. 5 was used, and the V part angle θ ₁ = 95°, θ ₂ = 120
゜, the cutting points were shifted by 90°, 4 sets were assembled, all of them were made of polytetrafluoroethylene resin, and as a comparative product, 8 rings were cut at 90° using a V-shaped packing with one cut point as shown in Fig. 1. I used one that was assembled at different locations. The V-shaped ring material was made of tetrafluoroethylene resin.

As a result of experiments on sealing performance as pressure increases under such conditions, it was found that the product of the present invention exhibits extremely excellent sealing performance, as confirmed by the sealing properties shown in Figure 6 of the drawing. did.

Therefore, in the present invention, as shown in FIG. 2, the conventional metal spacer ring is inappropriate and the purpose thereof cannot be achieved.

As detailed above, in the present invention, a V-shaped packing, that is, a convex abdominal part of an annular packing having a V-shaped cross section, and a concave back surface part of a V-shaped secondary packing, that is, an annular secondary packing having a V-shaped cross section. A pair of sealing members are formed by closely fitting at least one cut point provided on each at a shifted position, and this sealing member is formed by the outer circumferential surface of the shaft and the inner circumferential surface of the gland box. This shaft sealing device has a configuration in which a plurality of shaft sealing devices are installed in a shaft sealing chamber. Therefore, the configuration of the present invention has the following advantages.

(1) Conventionally, this type of shaft seal device was inconvenient to install and remove, but now it can be installed and removed with a simple operation.

(2) Despite having a cut point, it can demonstrate a sealing function equivalent to or better than one without a cut point.

(3) Additional tightening (tightening allowance) is possible. That is, the configuration is such that a gap can be formed between the sealing members without reducing the sealing effect.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views of a shaft sealing device using a conventional V-shaped packing, FIG. 3 is a perspective view of a conventional V-shaped packing, and FIG. 4 is a shaft sealing device according to the present invention. 5 is a cross-sectional view of the main part (sealing member) of FIG. 4.
The enlarged sectional view and FIG. 6 are graphs showing sealing characteristics in experimental examples.

Claims (1)

[Claims] 1. A convex ventral surface part of an annular packing having a V-shaped cross section with one cut point on the circumference, and a concave back surface part of an annular secondary packing having a V-shaped cross section and one cut point on the circumference. A pair of sealing members are formed by closely fitting each cut point at a shifted position, and the angle θ ₁ of the V part of the concave back surface with a V-shaped cross section and the convex ventral surface part of the V-shaped cross section in this sealing member are formed. A shaft sealing device characterized in that a plurality of the sealing members, each of which has an obtuse angle θ ₂ of the V portion and has a relationship of θ ₂ >θ ₁ , are mounted in a shaft sealing chamber.