JPH07224947A - Stationary type mechanical seal - Google Patents

Abstract

PURPOSE:To offer a stationary type mechanical seal without making any contact or the like with a casing due to the weight of driven ring. CONSTITUTION:A circumferential groove 6 is formed on the inner circumferential side of a supporting ring 3 and a single or a plurality of balls 5 are mounted on the lower portion in the gravitational direction of a driven ring. The ball 5 receives the weight of the driven ring by coming into contact with the outer circumference of the driven ring. The circumferential groove 6 has a specified length in the axial direction and the ball 5 is made capable of driven movement inside the circumferential groove 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a static mechanical seal.

[0002]

2. Description of the Related Art Mechanical seals are used in various fields as a seal between a rotary shaft of a device having a rotary shaft and a casing of the device. There are mechanical seals of the type in which the seat ring on the casing side can be driven and those of the non-driven type.When the seat ring can be driven, the rotary ring on the rotating shaft side is not This type is called the static type because it is driven. An O-ring is usually provided between the driven ring and the casing side to seal between them.

[0003]

However, in a mechanical seal of a large machine having a rotating shaft of several hundred mm or the like, and the rotating shaft is installed laterally, the driven ring also becomes large accordingly. Since the weight also increases, a large weight is applied to the lower side of the driven ring. Therefore, the weight of the driven ring cannot be supported only by the O-ring interposed between the driven ring and the casing side, and the driven ring and the casing side come into contact with each other. However, there is a problem that the resistance is increased or the resistance in the driven direction becomes large, and it becomes difficult to follow the driving, and the sealing property deteriorates. In particular, when the driven ring is divided into two parts, the weight of the driven ring is further increased, which is a serious problem. There was also a problem that the tightening margin of the O-ring was different between the upper side and the lower side. That is, there is a problem that the upper part has a small tightening margin and causes leakage, and conversely, the lower part has a large tightening margin and damages the O-ring. The present invention has been made to solve the above-mentioned problems of the prior art. Even if the driven ring has a large weight, the static mechanical system that can maintain a good sealing property without causing contact with the casing. Intended to provide a seal.

[0004]

In order to achieve the above object, in a static mechanical seal of the present invention, a load receiving member is axially movable between a driven ring and a casing side. This member is characterized by receiving the load of the driven ring. As the member, a sphere having a strength capable of withstanding a load can be used, and the sphere may be mounted in a circumferential groove having a predetermined length in the axial direction so as to be movable in the axial direction. This groove may be provided on either the driven ring side or the casing side, or a supporting ring may be provided on the casing side and provided on this supporting ring. The number of spheres may be one or more, and preferably a plurality of spheres are mounted in the circumferential direction. In addition, the driven ring may be divided into two or may be divided into a plurality of more than two, or may be a complete ring which is not divided.

[0005]

The load receiving member prevents the driven ring from coming into contact with the casing side, suppresses the change in the tightening margin of the O-ring, and prevents leakage and damage. Further, since the member is interposed so as to be movable in the axial direction, it does not hinder the driven ring and does not deteriorate the sealing performance. Also, when using a sphere as a member mounted in the groove,
Since the axial mobility is improved and the driven resistance of the driven ring is reduced, the sealing performance can be further improved.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, the shaft S is a large-diameter shaft of 450 mm, which is arranged in a substantially horizontal direction and is projected from the casing C of the device body and supported by the bearing 4. 40 is a bearing cover. The shaft S and the casing C are sealed by a static mechanical seal. This mechanical seal includes a driven ring 1 and a rotary ring 2, and is configured to seal the inside X of the machine by a sealing surface F formed by the driven ring 1 and the rotary ring 2.

The rotary ring 2 is mounted on the shaft S via an O-ring 20, and rotates together with the shaft S without being driven in the axial direction. In this embodiment, the rotary ring 2 is divided into two parts. The rotary ring 2 is formed by fastening two members with bolts 25. The rotating ring 2 may be divided into a number of 3 or more, or may be a non-divided unit.

The driven ring 1 is provided on the atmosphere side Y of the rotary ring 2 and mounted on the casing C side. In this embodiment, it is mounted on the casing C side so that it can be driven in the axial direction via a support ring 3 mounted by bolts or the like on the end of the casing C. The driven ring 1 is provided with an extending end 12 extending in the axial direction on the rear end side, and the extending end 12 is fitted on the inner peripheral side of the support ring 3. An O-ring 11 is provided between the extending end 12 and the inner circumference of the support ring 3 so as to seal between the driven ring 1 and the support ring 3. The driven ring 1 is pressed by the spring 10 toward the rotating ring 2. The support ring 3 is also divided into two parts in this embodiment, and the support ring 3 is formed by fastening two members with bolts 15. The support ring 3 is also 3
It may be divided into the above number or may be a non-divided single unit.

A circumferential groove 6 is formed on the atmosphere side Y of the O-ring 11 on the inner circumference of the support ring 3, and a ball 5 is mounted therein. The circumferential groove 6 has a predetermined length in the axial direction, and the ball 5 is movable in the axial direction by this length. As shown in FIG. 2, the balls 5 may be mounted only on the lower side of the circumferential groove 6 in the direction of gravity. In this embodiment, seven balls 5 are arranged in the circumferential direction. Each ball 5 has a diameter corresponding to the depth of the circumferential groove 6, and the balls 5 contact the outer circumference of the driven ring 1 to receive the weight of the driven ring 1. The balls 5 need to have a strength capable of receiving the load of the driven ring 1. In this embodiment, steel balls for ball bearings are used, but balls made of ceramic, carbon, or synthetic resin can also be used. The shape of the driven ring 1 is arbitrary as long as it can be moved in the axial direction and does not hinder the driven ring 1 from being driven. For example, a roller shape or the like is also possible.

Although a plurality of balls 5 are used in this embodiment, a single ball may be used depending on circumstances. Further, although a plurality of them are arranged in the circumferential direction, it is possible to increase the axial length of the circumferential groove 6 so that a plurality of them are arranged in the axial direction. Aspects can be adopted. Further, although the circumferential groove 6 is formed in the entire circumferential direction, it may be formed only in the lower portion in the direction of gravity.

FIG. 3 shows another embodiment, in which a retainer 50 used for a ball bearing or the like is used and is constructed so as to prevent the balls 5 from coming into contact with each other.

In the above construction, even if the driven ring 1 is large as in this embodiment, and the weight is large due to the split structure, the O-ring 11 can receive the weight of the driven ring 1 by the balls 5. Is not overloaded. In addition, the driven ring 1 may come into contact with the support ring 3 to damage it,
There is no danger that the driven ring 1 is obstructed and the contact with the rotary ring 2 is reduced, and the sealing performance is degraded. Further, since the ball 5 itself rolls in the circumferential groove 6 in the axial direction in accordance with the driven ring 1 to be driven, sliding between the ball 5 and the driven ring 1 does not occur. Therefore, the driven ring 1 is not adversely affected, and sliding friction is not generated between the driven ring 1 and the balls 5.

Although the circumferential groove 6 is formed on the support ring 3 side in the above embodiment, it may be formed on the outer peripheral side of the driven ring 1. Also, the driven ring 1 via the support ring 3
Is attached to the casing C side, but the driven ring 1 may be attached directly to the casing C without using the support ring 3. In this case, the circumferential groove 6 is naturally provided on the inner circumference of the casing C or the outer circumference of the driven ring 1.

[0014]

As described above, in the static mechanical seal of the present invention, a member for receiving a load is interposed between the driven ring and the casing side so as to be movable in the axial direction, and the driven ring of this member is provided. Since the load is received, the driven ring does not come into contact with the casing side by the load receiving member. Further, since the member is interposed so as to be movable in the axial direction, it does not hinder the driven ring and does not deteriorate the sealing performance. Further, no friction occurs between the driven ring and the member. Further, when a spherical body is used as a member by mounting it in the groove, the mobility in the axial direction is improved and the driven resistance of the driven ring can be reduced, so that the sealing property can be further improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA in FIG.

FIG. 3 shows another embodiment of the present invention AA in FIG.
FIG.

[Explanation of symbols]

1: driven ring, 2: rotating ring, 3: support ring, 4: bearing,
5: ball, 6: circumferential groove, 10: spring, 11: O
Ring, 12: extended end, 20: O-ring, 25: bolt, 30: O-ring, 40: bearing cover, 50: cage.

Claims (5)

[Claims] 1. A static mechanical seal comprising: a rotary ring that is mounted on a rotary shaft and is not driven in the axial direction; and a driven ring that is mounted on a casing side and is mounted so as to be driven in the axial direction. A static mechanical seal characterized in that a load receiving member is interposed between a casing side to which is mounted and a driven ring so as to be movable in the axial direction, and the load of the driven ring is received by the member. 2. A static mechanical seal, comprising: an axially non-driven rotary ring that is mounted on a rotary shaft that is installed in a lateral direction; and a driven ring that is axially followably mounted on the casing side. A circumferential groove having a predetermined length in the axial direction is provided in the lower portion in the direction of gravity between the driven ring and the casing side, and a single or plural spherical body having rigidity capable of receiving the load of the driven ring of the groove is provided. A static mechanical seal, wherein the static mechanical seal is mounted so as to be movable in the axial direction, and receives the load of a driven ring of the sphere. 3. The static mechanical seal according to claim 2, wherein a support ring is provided on the casing side, the groove is formed in the support ring, and the sphere is mounted on the support ring. 4. The static mechanical seal according to claim 2, wherein a plurality of spherical bodies are mounted in the circumferential direction. 5. The static mechanical seal according to claim 1, 2 or 3, wherein the driven ring is a split ring.