JPH07286672A - Shaft sealing device - Google Patents

Abstract

PURPOSE:To carry out stable aerial operation for a long time and to dispense with maintenance in an end face type shaft sealing device used for a rainwater drain pump or the like operated in the air by providing a means which rolls in sealing fluid by means of a rotary ring and feeds it to a sliding face. CONSTITUTION:A rotary ring 8 is fixed in a rotary flange 9 integrated with a rotary shaft 1, and a blade 10 and a through hole 11... are arranged in the inside of the rotary ring 8. A circumferential groove is arranged on the sliding face of the blade 10, and the through hole 11 is arranged on the circumferential groove. On the other hand, a fixed ring 7 fixed in a fixed flange 5 via a secondary seal 4 and an elastic body 6 is arranged in a casing 3 while pressed against the rotary ring 8. Air inside the casing 3 is entrained by means of the blade 10 arranged in the rotary ring 8 so as to be led to the sliding face, and consequently, the rotary ring 8 and the fixed ring 7 are cooled. The sliding face of the rotary ring 8 is formed of a coating made of silicon carbide or the like, while the sliding face of the fixed ring 7 is formed of a coating made of tungsten carbide group cemented carbide or the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an end face type shaft sealing device used in a rainwater drainage pump or the like which operates in the air.

[0002]

2. Description of the Related Art Due to rapid urbanization in recent years, the inflow of rainwater into drainage pump stations is becoming large and rapid. In order to deal with such a situation, there is an increasing demand for the drainage pump to be operated in advance and standby. In the drainage pump that performs the preceding standby operation, the pump is activated and the main shaft is rotated, but the pump is not pumped, that is, the operation is performed in the air for a long time. During this time, since the lubricating water is not supplied to the shaft sealing device by pumping water, the shaft sealing device has problems such as abnormal wear of the sliding member due to dry sliding and deterioration of sealing performance.

As a means for solving such a problem, conventionally, the methods shown in FIGS. 11 and 12 have been adopted. Figure 1
The method shown in FIG. 1 is a method in which the lubricating water 21 in the lubricating water tank 20 installed outside is supplied to the sliding portion by the water supply pump 18 through the pipe 19 and the circumferential groove 12, which is the lower part of the shaft sealing device. Whether or not is flooded is detected by a full water detector, etc., and if it is not flooded, lubrication water is poured, and if flooding is detected, water filling is stopped. On the other hand, in the method shown in FIG. 12, the rubber bellows 15 is used to push down the fixed ring 7 to prevent the sliding portion from contacting when the pump is stopped and in the air, and when the pumping is performed, the pressure of the pumping water is increased by the pressure receiving plate 18. This is a method of pressing and fixing the fixed ring 7 upward by utilizing.

[0004]

However, in the shaft sealing device of the method as shown in FIG. 11, water is constantly poured into the shaft sealing portion during the air operation, so that it is necessary to perform the air operation for a long time. There is a drawback that a large amount of lubricating water is required. In addition, there is a drawback that the cost becomes high when fresh water is used as the lubricating water. Furthermore, since a full water detector, a water supply pump, a water supply pipe, etc. are required, maintenance of these auxiliary machines becomes necessary.

On the other hand, in the structure as shown in FIG. 12 in which the sliding member is not brought into contact with the sliding surface during the stop and the air operation, dust or the like may be accumulated on the sliding surface when the pump is not operated for a long time. . If the sliding surface is scratched by the dust or the like, it may cause surface roughening or abnormal wear, making it impossible to maintain sufficient sealing performance. Further, in the drainage pump, the pressure of the sealed fluid often becomes not only positive pressure but also negative pressure depending on the operating state. In this case, the fixed ring 7 that has been pressed upward by the pressure receiving plate 18 is pressed downward, so that the atmosphere is sucked into the pump casing and the pump performance deteriorates.

Further, in such a drainage pump, since a large amount of earth and sand is contained in the pumped water, there is a possibility that the sliding member may be abnormally worn and the sealing performance may be deteriorated due to the inclusion of earth and sand even under normal operating conditions. is there. Therefore, it was not possible to stably and repeatedly perform air operation for a long period of time without supplying lubricating water from the outside of the pump.

An object of the present invention is to provide a maintenance-free shaft seal device which can be stably operated repeatedly in the air for a long time without supplying lubricating water from the outside of the pump.

[0008]

In order to achieve the above object, the present invention is capable of operating a shaft sealing device in a stable state for a long time even when the pump is operating in air and without supplying lubricating water from the outside. In addition, a mechanism for supplying lubricating water to the sliding surface by rotating the main shaft is provided so that sufficient sealing performance can be obtained even when pumping water.

That is, a fixed flange for supporting the fixed ring is attached to the casing via an elastic body such as a spring or bellows, and the surface pressure of the sealed portion is kept at an appropriate value, and a tungsten carbide type cemented carbide is used as the fixed ring. By using silicon carbide as the rotary ring, the wear resistance during dry sliding is improved, and the side surface of the rotary ring or the flange supporting the rotary ring is configured like an impeller so that the main shaft rotates. The pumped liquid in the casing is supplied to the sealed portion.
By combining this structure with a dynamic pressure groove, it is possible to reduce the surface pressure of the sealed portion during dry sliding.

[0010]

According to the present invention, in dry sliding, the impeller cools the rotary ring and the fixed ring by taking in the surrounding air and directly or through the communication hole. In addition, since the surface pressure can be reduced by the dynamic pressure effect of the dynamic pressure groove provided on the sliding surface, the sliding performance of dry sliding is improved, and problems such as seizure and surface roughness of the sliding member occur. There is no. On the other hand, during negative pressure operation, the pumping liquid around the impeller is entrained and the rotary ring and fixed ring are cooled as in dry sliding, contributing to lubrication of the sliding surface and seizing the sliding member. There is no rough surface. Also,
Since the lubricating liquid is present on the sliding surface, the atmosphere is not sucked into the casing, and there is no fear of degrading the pump performance. In the present invention, an external water supply piping system is unnecessary, maintenance of piping and auxiliary equipment is not required, and reliability of the entire device is improved. Therefore, it is not necessary to inject water from outside even when repeating air operation without pumping or during negative pressure operation.
It is possible to provide a highly reliable shaft sealing device that can be stably operated for a long time.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing the structure of a shaft sealing device according to an embodiment of the present invention. A rotary flange 9 on the rotary shaft 1.
Is fixed, and the rotary ring 8 is fixed to the rotary flange 9. Inside the rotary ring 8, the blade 10 and the communication hole 1
1 is provided. A circumferential groove 12 is provided on the sliding surface of the blade 10. As shown in FIG. 7, the communication holes 11 are arranged in the circumferential direction on the circumferential groove 12. On the other hand, a fixed flange 5 is axially movably supported on the casing 3 via a secondary seal 4 and an elastic body 6. A fixed ring 7 is fixed to the fixed flange 5, and the fixed ring 7 is pressed against the rotary ring 8 by an elastic body 6. When the time from the start of pump operation to pumping is long and air operation is forced, as represented by the preceding atmospheric operation, the seal formed by the fixed ring 7 and the rotary ring 8 is in a dry sliding state. Become. However, in the present invention, the sliding surface of the rotary ring 8 is formed of silicon carbide or a silicon carbide based alloy film, and the sliding surface of the fixed ring 7 is a tungsten carbide type cemented carbide or a tungsten carbide type cemented carbide. Since it is formed of a film, dry sliding is possible with a surface pressure of 0.1 MPa or less. Further, in the present invention, as the rotary shaft 1 rotates, the air inside the casing 3 is entrained by the blades 10 provided on the rotary ring 8 and reaches the sliding surface through the communication hole 11 and the circumferential groove 12.
As a result, the rotary ring 8 and the fixed ring 7 are cooled and the reliability of dry sliding can be improved, so that the sliding surfaces of the rotary ring 8 and the fixed ring 7 are kept sound. Under actual operating conditions, after such an air operation, a normal operating state with pumped water is obtained. In normal operating conditions, pumping water may have a positive pressure or a negative pressure. In the case of positive pressure, there is no particular problem because the pumped water flows into the sliding surface due to the pressure difference with the atmosphere outside the casing 3, but in the case of negative pressure, the atmosphere tries to flow into the casing 3 due to the pressure difference. Therefore, even if pumped water is present around the shaft seal device, the sliding surface is not lubricated, and if a large amount of air flows into the casing 3, the pump performance may be deteriorated. However, in the present invention, rotation of the rotary shaft 1 causes the rotary ring 8 to rotate.
The pumped water in the casing 3 is entrained by the blades 10 provided in the rotor 3, lubricates the sliding surface through the communication hole 11 and the circumferential groove 12, and the rotary ring 8 and the fixed ring 7 are cooled. And the sliding surface of the fixed ring 7 is kept sound. Therefore, according to the present invention, since the sliding surface can be maintained in a sound state without providing an external device, it is possible to repeatedly operate under any of the air operation, positive pressure, and negative pressure.

FIG. 2 is a sectional view of a shaft sealing device showing a second embodiment of the present invention. In this embodiment, the rotary shaft 1 is provided with a toothed wheel 22.
Is fixed, and the rotary ring 8 is fixed to the impeller 22. Further, the inside of the impeller 22 and the circumferential groove 12 provided on the sliding surface of the rotary ring 8 communicate with each other through a communication hole 11. Further, the front view of the rotary ring 8 viewed from the direction A is as shown in FIG. 7, and the communication hole 11 is formed on the circumferential groove 12 as in the first embodiment.
Are arranged. As a result, the rotary shaft 1 is also used in this embodiment.
As the air or the pumped liquid in the casing 3 is supplied to the sliding surface through the communication hole 11 with the rotation of FIG.
The same action and effect as can be obtained. Further, FIG. 3 shows a third embodiment of the present invention, in which a plurality of blades 10 are provided on the outer peripheral side upper part of the rotary ring 8 fixed to the rotary flange 9.
Is provided. A front view of the rotary ring 8 viewed from the B direction is as shown in FIG. Also in this embodiment, as the rotary shaft 1 rotates, air or pumped liquid around the sealed portion is caught by the blades 10 on the sliding surface, so that the sliding surface is cooled and lubricated as in the first embodiment.

FIG. 4 is a sectional view of a shaft sealing device showing a fourth embodiment of the present invention. In this embodiment, a dynamic pressure groove 13 is further added to the rotary ring 8 of the embodiment shown in FIG. As shown in FIG. 9, the dynamic pressure groove is arranged on the outer peripheral side of the circumferential groove 12 provided on the sliding surface of the rotary ring 8. In this embodiment, in addition to the action and effect described in the first embodiment, the dynamic pressure effect by the dynamic pressure groove can be obtained. That is, when the rotary ring 8 rotates, air or pumped liquid is trapped in the dynamic pressure groove 13 to generate a pressure, which acts in a direction to push the fixed ring 7 and the fixed flange 5 upward. In this case, there may be a problem that the sealing portion is opened due to the dynamic pressure and the sealing performance is deteriorated. Pressure is needed to overcome the reaction force of. However, since such a large force is not generated only by the dynamic pressure, the sealing performance does not deteriorate due to the opening of the sealing portion, and only the surface pressure of the sliding portion is reduced. As a result, the sliding performance at the time of dry sliding is improved, so that the reliability of the shaft sealing device can be further enhanced. Also in FIG.
4 is a fifth embodiment in which the rotary ring 8 of the embodiment shown in FIG. 2 is provided with a dynamic pressure groove 13 similar to that in the case of FIG. 4, and the same effect as the above-mentioned embodiment can be obtained.

In the examples, no particular mention is made of the trapping of earth and sand contained in the pumping liquid. However, as described above, the sliding portions of the rotary ring 8 and the fixed ring 7 of the present invention are made of silicon carbide or tungsten carbide type super alloy. Since a material having a high hardness such as a hard alloy is used, there is no problem that the sealing performance is deteriorated due to damage of the sliding surface even if sand and sand are caught. Further, although it is conceivable that earth and sand accumulate in the communication hole 11 and the dynamic pressure groove, etc., since the communication hole 11 and the dynamic pressure groove 13 are all on the rotation side, the accumulated earth and sand are diffused into the casing by centrifugal force. . FIG. 6 shows a sixth embodiment for further improving the reliability of sediment. Discharging for discharging sediment by communicating the sliding surface and the casing with the fixed ring 7 of the embodiment described in FIG. The holes 14 are provided. Since the discharge hole 14 is provided at a position facing the circumferential groove 12 provided in the rotary ring 8, the earth and sand that has passed through the communication hole 11 of the rotary ring 8 is quickly discharged to the outside of the shaft sealing device. . Therefore, the other effects are similar to those of the embodiment of FIG.

[0015]

According to the present invention, since the sliding surface can be cooled or lubricated by the rotation of the rotary shaft without supplying the lubricating water from the outside, the sliding surface is not damaged for a long time. It is possible to perform aerial operation and operation under negative pressure conditions. Further, in the present invention, since an external water supply device and its piping system are not required, maintenance of these auxiliary machines and piping is not necessary. Further, the material of the seal ring, which is a combination of silicon carbide and tungsten carbide type cemented carbide, which have excellent wear resistance, is not only resistant to dry sliding but also resistant to earth and sand, and thus has a long service life. On the other hand, the elements constituting the shaft sealing device have few movable parts and the number of parts can be small. Therefore, even if the air operation is repeatedly performed, it is possible to stably operate the pump for a long period of time without requiring water injection from the outside.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a shaft sealing device according to an embodiment of the present invention.

FIG. 2 is a sectional view of a shaft sealing device according to a second embodiment of the present invention.

FIG. 3 is a sectional view of a shaft sealing device according to a third embodiment of the present invention.

FIG. 4 is a sectional view of a shaft sealing device according to a fourth embodiment of the present invention.

FIG. 5 is a sectional view of a shaft sealing device according to a fifth embodiment of the present invention.

FIG. 6 is a sectional view of a shaft sealing device according to a sixth embodiment of the present invention.

FIG. 7 is a front view of a rotary ring of the shaft sealing device shown in FIGS. 1 and 2.

8 is a front view of a rotary ring of the shaft sealing device shown in FIG.

9 is a front view of a rotary ring of the shaft sealing device shown in FIGS. 4, 5, and 6. FIG.

10 is a sectional view of an impeller of the shaft sealing device shown in FIGS. 2 and 5. FIG.

FIG. 11 is a sectional view of a conventional shaft sealing device.

FIG. 12 is a sectional view of a conventional shaft sealing device.

[Explanation of symbols]

1 ... Rotating shaft, 2 ... Sleeve, 3 ... Casing, 4 ... Secondary seal, 5 ... Fixed flange, 6 ... Elastic body, 7 ... Fixed ring,
8 ... rotary ring, 9 ... rotary flange, 10 ... blade, 11 ... communicating hole, 12 ... circumferential groove.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yusuke Arai, 603 Kandachi-cho, Tsuchiura-shi, Ibaraki Hitate Factory Tsuchiura Plant

Claims (7)

[Claims] 1. A rotary shaft, a rotary flange fixed to the rotary shaft, a holding member supported by the rotary flange via an elastic body, a rotary ring fixed to the holding member, and a casing. In a shaft sealing device having a fixed fixing flange and a fixed ring fixed to the fixed flange and facing the rotating ring to form a sealing portion, means for supplying a sealing fluid to the sliding surface by the rotating ring. A shaft sealing device characterized by being provided with. 2. A rotary shaft, a rotary flange fixed to the rotary shaft, a holding member supported by the rotary flange via an elastic body, a rotary ring fixed to the holding member, and a casing. In a shaft sealing device having a fixed fixing flange and a fixed ring fixed to the fixed flange and facing the rotary ring to form a sealing portion, means for supplying a sealing fluid to the sliding surface by the fixed flange. A shaft sealing device characterized by being provided with. 3. The shaft sealing device according to claim 1, wherein a dynamic pressure groove is provided on a sliding surface of the rotary ring. 4. The shaft sealing device according to claim 1, wherein a circumferential groove is provided on a sliding surface of the rotary ring or the fixed ring. 5. The shaft sealing device according to claim 1, wherein a circumferential groove is provided on a sliding surface of the rotary ring or the fixed ring, and a dynamic pressure groove is provided on the rotary ring. 6. The method according to claim 1, 2, 3, 4 or 5.
A shaft sealing device in which the material of the rotary ring is silicon carbide and the material of the fixed ring is tungsten carbide type cemented carbide. 7. The method according to claim 1, 2, 3, 4 or 5,
A shaft sealing device, wherein the sliding surface of the rotary ring is coated with a silicon carbide based alloy film, and the sliding surface of the fixed ring is coated with a tungsten carbide based cemented carbide film.