JPH05263949A - Shaft sealing device of bearing oil tank - Google Patents

Abstract

PURPOSE:To prevent oil and oil mist in a bearing oil tank from mixing in the magnetic fluid of a magnetic fluid shaft sealing device. CONSTITUTION:A shaft sealing device 19 sealing a tuning shaft 1 of a rotary machine consists of a magnetic fluid shaft sealing device 20 and an air supply type sealing device 21 set up adjacently with each other. This air supply type shaft sealing device 21 is situated nearer to the side of a bearing oil tank than the magnetic fluid shaft sealing device 20. Since a flow of high pressure air to be fed to the air supply type shaft sealing device 21 from a feed pipe 28 runs to the bearing oil tank side, oil and an oil mist from the inside of the bearing oil tank is prevented from penetrating into the sealing device 20 as well as mixing into the magnetic fluid 24. The high pressure air taken into the sealing device 21 is discharged out of an exhaust pipe 29 together with the oil and the oil mist from the bearing oil tank.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shaft seal device for a bearing oil tank, and more particularly to a rotating machine supported in the oil of a bearing oil tank in a rotating machine such as a generator or a pump turbine or a water turbine used in a hydraulic power generation facility. The present invention relates to a bearing oil tank shaft seal device that seals a shaft to prevent leakage of oil and oil mist in the bearing oil tank.

[0002]

2. Description of the Related Art Generally, in rotary machines such as pump turbines, turbines and generators used in hydroelectric power generation facilities, a rotary shaft is supported by bearings in a bearing oil tank. For this reason, if the shaft is not reliably sealed between the rotating shaft and the stationary part, it will not only hinder operation and maintenance, but also oil and oil mist will leak out of the bearing oil tank or outside of the rotating machine, and It becomes a big problem. FIG. 5 shows a conventional bearing device for a rotary machine, in which a rotary shaft 1 of the rotary machine is supported by a thrust bearing 3 via a thrust rotary plate 2. The thrust bearing 3 is mounted on a thrust bearing base 5 via a thrust bearing spring 4, and the thrust bearing base 5 is fixed to a bearing bracket 6. The side surface of the rotary shaft 1 is supported by a guide bearing 7, and the guide bearing 7 is supported by a bearing support 8.

A bearing oil cylinder 9 is attached to the bearing bracket 6, and the bearing bracket 6 and the bearing oil cylinder 9 constitute a bearing oil tank 69. The rotating shaft 1, the thrust bearing 3, the guide bearing 7, etc. are immersed in the oil in the bearing oil tank 69. Further, the oil cooler 10 is arranged in the bearing oil tank 69. A stationary side oil drainer 11 is installed above the bearing oil tank 69, and a supply type shaft seal device 12 is provided at a seal portion between the stationary side oil drainer 11 and the rotary shaft 1. An air supply pipe 13 and an exhaust pipe 14 are connected to the air supply type shaft seal device 12, and the air supply pipe 13 supplies air having a pressure higher than the air pressure in the bearing oil tank to the air supply type shaft seal device 12. The rotating shaft 1 is sealed to prevent oil outflow from the bearing oil tank and oil mist scattering. However, recently, in hydroelectric machines such as generators of hydroelectric power generation facilities and hydraulic machines such as turbines and pump turbines, bearing devices tend to be used at high speed and under heavy load, and the pressure difference between the inside and outside of the shaft seal device fluctuates sharply. With the air supply type shaft seal device 12, it is impossible to expect a sufficient seal.

Therefore, such an air supply type shaft seal device 1 is provided.
A magnetic fluid shaft seal device is known as a shaft seal device that solves the problem (2). FIG. 6 shows a bearing device of a rotary machine provided with this magnetic fluid shaft seal device. The magnetic fluid shaft seal device 15 includes a pole piece 16, a permanent magnet 17, and a magnetic fluid 18 which are supported by a stationary oil drainer 11. Composed of and. The magnetic fluid 18 is filled in the gap between the outer peripheral surface of the rotary shaft 1 and the end surface of the stationary oil cutoff 11 facing the outer peripheral surface, and is held in the above gap by its own surface tension and magnetic force. .. Since the magnetic fluid seal device 15 having such a structure is a contact seal between a liquid and a solid, it can maintain high airtightness and is excellent in durability without wear.

[0005]

However, since the oil or oil mist contacts the magnetic fluid at the seal boundary surface in the magnetic fluid seal device, the oil or oil mist gradually mixes with the magnetic fluid, and the magnetic fluid seal device may be operated for a long period of time. There is a problem that the magnetic force of the magnetic fluid is reduced, the sealing effect is also reduced accordingly, oil or oil mist leaks from the bearing oil tank, and the magnetic fluid itself also flows into and out of the bearing oil tank. Further, in the above magnetic fluid seal device, since the magnetic fluid is held in the gap between the stationary side oil drainer and the rotating shaft by the surface tension and magnetic force due to its viscosity, the above-mentioned mixing of oil, heat generation of the seal device, etc. There is a problem that the magnetic fluid flows out of the bearing oil tank due to the deterioration of the performance of the magnetic fluid and the deterioration of the performance of the permanent magnets. Further, when disassembling and assembling the magnetic fluid seal device during maintenance and inspection, the magnetic fluid is collected from the gap between the stationary side oil drainer and the rotary shaft and refilled therein. However, there is also a problem in that the magnetic fluid easily falls into the bearing oil tank during this work, which requires skill.

Therefore, an object of the first invention of the present application is to prevent the oil and mist in the bearing oil tank from mixing with the magnetic fluid of the magnetic fluid shaft seal device and to endure long-term use. To provide a shaft seal device of. It is an object of the second and third inventions of the present application to provide a shaft oil seal device for a bearing oil tank which can prevent the magnetic fluid from flowing out and can easily collect and refill the magnetic fluid.

[0007]

To achieve this object, a first invention of the present application is a bearing oil tank shaft seal device for sealing a rotating shaft of a rotating machine supported in oil in a bearing oil tank, The shaft seal device is composed of a magnetic fluid shaft seal device and an air supply type shaft seal device which are arranged adjacent to each other, and the air supply type shaft seal device is located closer to the bearing oil tank than the magnetic fluid shaft seal device. It is characterized by that. With this configuration, the air supply type shaft seal device includes the first air chamber adjacent to the magnetic fluid shaft seal device, the second air chamber adjacent to and in communication with the first air chamber, and the second air chamber. 3rd adjacent to and communicating with 2 air chambers
It is desirable to include an air chamber, an air supply pipe for supplying air having a higher pressure than the atmosphere in the bearing oil tank to the second air chamber, and an exhaust pipe connected to the third air chamber.

A second aspect of the present invention is a bearing oil tank shaft seal device for sealing a rotating shaft of a rotating machine supported in oil in a bearing oil tank, wherein a ring-shaped horizontal flange protruding from the rotating shaft. On a horizontal upper surface of the portion, a ring-shaped concave portion formed in a circumferential shape so as to be concentric with the rotation axis,
A magnetic fluid filled in the ring-shaped recess, a pole piece whose one end is immersed in the magnetic fluid in the ring-shaped recess, and a permanent magnet for exciting the pole piece. To do.

According to a third aspect of the present invention, in a bearing oil tank shaft seal device for sealing a rotating shaft of a rotating machine supported in oil in a bearing oil tank, the bearing oil tank is attached to the bearing oil tank so as to surround the rotating shaft. Ring-shaped pole piece, a permanent magnet that excites the pole piece, a ring-shaped concave portion that is engraved on the horizontal upper surface of the pole piece so as to be concentric with the rotation axis, and the ring-shaped pole piece. The magnetic fluid filled in the concave portion, a ring-shaped flange portion projecting from the rotating shaft and located above the pole piece, and a flange portion hung from the outer peripheral portion of the flange portion, the lower end of which is located in the concave portion. And a hanging part immersed in a magnetic fluid.

[0010]

In the first aspect of the invention, the shaft seal device is doubly sealed by the magnetic fluid shaft seal device and the air supply type shaft seal device which are arranged adjacent to each other. The air supplied to the air supply type shaft seal device flows into the bearing oil tank side due to the magnetic fluid sealing effect of the magnetic fluid shaft seal device, so that the splashed oil and oil mist in the bearing oil tank can be sealed by the magnetic fluid shaft seal device. Prevents it from entering the device and entering the magnetic fluid.

According to the second aspect of the invention, the horizontal flange portion rotates integrally with the rotary shaft, and during this rotation, one end of the pole piece is constantly immersed in the magnetic fluid in the recess of the horizontal flange portion. .. Therefore, the shaft seal device seals the rotary shaft by the magnetic fluid in the horizontal flange portion and the ring-shaped recess on the rotating side and the pole piece on the stationary side. Since the magnetic fluid is contained in the ring-shaped recess of the horizontal flange, it does not flow out into or out of the bearing oil tank, and its recovery and refilling can be easily performed.

In the third aspect of the invention, the flange portion rotates integrally with the rotary shaft in a state where the hanging portion is normally ring-shaped and is immersed in the magnetic fluid in the concave portion. Therefore, the shaft sealing device seals the rotary shaft by the flange portion and the hanging portion on the rotating side, the pole piece on the stationary side, and the magnetic fluid in the ring-shaped recess. Since the magnetic fluid is filled in the concave portion formed on the horizontal upper surface of the pole piece, it does not flow into and out of the bearing oil tank, and the recovery and refilling can be easily performed.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a bearing oil tank shaft seal device according to the present invention will be described below with reference to FIGS. 1 to 4 in which the same parts as those in FIGS. 1 and 2
Shows an embodiment of a shaft seal device for a bearing oil tank according to the first invention, in which a rotary shaft 1 of a rotary machine is a thrust rotary plate 2
It is supported by the thrust bearing 3 via. The thrust bearing 3 is mounted on a thrust bearing base 5 via a thrust bearing spring 4, and the thrust bearing base 5 is fixed to a bearing bracket 6. The side surface of the rotary shaft 1 is supported by a guide bearing 7, and the guide bearing 7 is supported by a bearing support 8.

A bearing oil cylinder 9 is attached to the bearing bracket 6, and the bearing bracket 6 and the bearing oil cylinder 9 constitute a bearing oil tank 69. The rotary shaft 1, the thrust bearing 3, the guide bearing 7, etc. are immersed in the oil in the bearing oil tank 69. Further, the oil cooler 10 is arranged in the bearing oil tank 69. Above the bearing oil tank 69, an oil tank cover attached to the bearing support 8, that is, a stationary side oil drainer 11 is installed, and a shaft seal device 19 is supported by this stationary side oil drainer 11. As shown in FIG. 2, the magnetic fluid shaft seal device 20 and the air supply type shaft seal device 21 are arranged adjacent to each other, and the air supply type shaft seal device 21 has a bearing oil tank more than the magnetic fluid shaft seal device 20. 6
It is located closer to the inside.

The magnetic fluid shaft seal device 20 comprises a pole piece 22, a permanent magnet 23 and a magnetic fluid 24. The magnetic fluid 24 is filled in the gap between the outer peripheral surface of the rotating shaft 1 and the end surface 22a of the pole piece 22 facing the outer peripheral surface. The air supply type shaft seal device 21 includes a first air chamber 25 adjacent to the magnetic fluid shaft seal device 20 and a second air chamber 26 adjacent to and in communication with the first air chamber 25.
A third air chamber 27 adjacent to and in communication with the second air chamber 26, and an air supply pipe 2 connected to the second air chamber 26.
8 and an exhaust pipe 29 connected to the third air chamber 27. The magnetic fluid 24 seals the gap between the one end 22a of the pole piece 22 adjacent to the first air chamber 25 and the rotary shaft 1.

Next, the operation of this embodiment will be described. The air supply pipe 28 supplies air having a higher pressure than the atmosphere in the bearing oil tank 69 to the second air chamber 26, and the high pressure air supplied to the second air chamber 26 is supplied to the first air chamber 25 and the third air chamber 27. To each of them. Since the magnetic fluid shaft seal device 20 maintains high airtightness, the high pressure air that has flowed into the first air chamber 25 stays there. Therefore, the high-pressure air continuously supplied from the air supply pipe 28 flows from the second air chamber 26 mainly into the third air chamber 27.

On the other hand, oil and oil mist enter the third air chamber 27 from the bearing oil tank 69. The oil or oil mist that has entered cannot enter the second air chamber 26 because of the high-pressure air flow that flows into the third air chamber 27 from the second air chamber 26, and exhausts from the third air chamber 27 together with the air flow. It is discharged via the pipe 29.
The discharged oil and oil mist are recovered by an oil recovery device (not shown) and returned to the bearing oil tank 69 again. In this way, the shaft seal device 19 double seals by the magnetic fluid shaft seal device 20 and the air supply type shaft seal device 21, so that a very high sealing effect can be obtained, and
Since the air supply type shaft seal device 21 blocks oil and oil mist in the bearing oil tank 69 and prevents oil and oil mist from mixing with the magnetic fluid 24 of the magnetic fluid shaft seal device 20, deterioration of the magnetic fluid is prevented. can do.

In the above embodiment, the pole piece 22 of the magnetic fluid shaft seal device 20 and the air chambers 25, 26 and 27 of the air supply type shaft seal device 21 are integrally formed by a single component. However, if the magnetic fluid shaft seal device 20 and the air supply type shaft seal device 21 are arranged adjacent to each other and the air supply type shaft seal device 21 is located on the inner side of the bearing oil tank 69 than the magnetic fluid shaft seal device 20. The pole piece 22 and each of the air chambers 25, 26, 27 may be formed by separate parts.

FIG. 3 shows an embodiment of a shaft seal device for a bearing oil tank according to the second aspect of the present invention, in which a rotary shaft 1 is provided with an annular horizontal flange portion 30 projecting horizontally from the outer periphery thereof. On the horizontal upper surface of the horizontal flange portion 30, a ring-shaped recess 31 is formed concentrically with the rotating shaft 1, and the ring-shaped recess 31 is filled with a magnetic fluid 32. The pole piece 33 has an annular shape and has an oil tank cover of the bearing oil tank 69,
That is, it is supported concentrically with the rotating shaft 1 by the oil drainer 34. One end 33a of the pole piece 33 is immersed in the magnetic fluid 32 in the ring-shaped recess 31, and the other end 33b faces the horizontal upper surface of the horizontal flange portion 30. The amount of the magnetic fluid 32 is set so that the one end 33a of the pole piece 33 is always in contact with the magnetic fluid 32 regardless of the vertical vibration of the rotating shaft 1. A ring-shaped permanent magnet 35 is attached to the pole piece 33.

Next, the operation of this embodiment will be described. The magnetic flux 36 from the permanent magnet 35 is applied to the one end portion 3 of the pole piece 33.
A closed magnetic circuit is formed through 3a, the magnetic fluid 32, the horizontal flange portion 30, and the other end 33b of the pole piece 33. Since the gap between the one end portion 33a of the pole piece 33 and the horizontal flange portion 30 is always filled with the magnetic fluid 32, the inside of the bearing oil tank 69 and the outside 37 thereof are completely cut off, and the inside of the bearing oil tank 69 is completely closed. Surely prevent the oil and oil mist from splashing and leaking to the outside 37. Since the magnetic fluid 32 is housed in the ring-shaped recess 31 in a horizontal state, even if the permanent magnet 35 is deteriorated, it does not drop or scatter due to centrifugal force. Three
It is possible to easily collect and refill 2. FIG. 4 shows an embodiment of a shaft seal device for a bearing oil tank according to the third invention. The oil drainer 34 attached to the bearing oil tank 69 has a ring-shaped pole piece concentric with the rotating shaft 1. 38 is fixed. A ring-shaped recess 39 is concentrically formed with the rotary shaft 1 on the upper surface of the pole piece 38.
The magnetic fluid 32 is filled in the ring-shaped recess 39. A ring-shaped permanent magnet 35 is embedded in the inner peripheral portion of the pole piece 38.

A ring-shaped flange portion 40 projects from the rotary shaft 1, and the flange portion 40 extends above the upper surface of the pole piece 38. A hanging portion 41 hangs downward from the outer peripheral end of the flange portion 40, and the lower end of the hanging portion 41 is sufficiently immersed in the magnetic fluid 32 in the ring-shaped recess 39. Next, the operation of the embodiment of the third invention will be described. The flange portion 40 and the hanging portion 41 rotate integrally with the rotating shaft 1. The magnetic flux 36 from the permanent magnet 35 is the pole piece 3
A closed magnetic circuit is formed through one end 38a of No. 8, the flange portion 40, the hanging portion 41, and the magnetic fluid 32. Since the gap between the lower end of the hanging part 41 and the ring-shaped recess 39 of the pole piece 38 is always filled with the magnetic fluid 32, the inside of the bearing oil tank 69 and the outside 37 thereof are completely cut off, and the bearing oil tank It securely prevents the oil and oil mist inside 69 from scattering and leaking to the outside. Since the magnetic fluid 32 is housed in the ring-shaped recess 39 in the horizontal state, even if the permanent magnet 35 is deteriorated, it does not drop or scatter due to centrifugal force, and the magnetic fluid at the time of maintenance and inspection. The fluid 32 can be easily collected and refilled.

The above embodiment relates to the bearing device of the vertical axis rotating machine used in the hydraulic power generation facility. However, the present invention can also be applied to a bearing device for a horizontal axis rotary machine, and further to a bearing device for a rotary machine other than a hydroelectric power generation facility.

[0023]

As is apparent from the above description, according to the first invention of the present application, the shaft seal device is composed of the magnetic fluid shaft seal device and the air supply type shaft seal device which are arranged adjacent to each other. Since the pneumatic shaft seal device is located closer to the bearing oil tank than the magnetic fluid shaft seal device, a high sealing effect can be obtained by the double seal of the magnetic fluid shaft seal device and the air supply type shaft seal device. Further, since the air supply type shaft seal device prevents the scattered oil and oil mist in the bearing oil tank from mixing with the magnetic fluid of the magnetic fluid shaft seal device, it is possible to prevent the magnetic fluid from deteriorating. The reliability of the sealing device can be improved and the service life can be extended.

Further, according to the second invention of the present application, the horizontal upper surface of the ring-shaped horizontal flange portion projecting from the rotary shaft is provided with:
A ring-shaped recess that is formed in a circumferential shape so as to be concentric with the rotation axis, and a magnetic fluid filled in the ring-shaped recess,
Since the pole piece whose one end is immersed in the magnetic fluid in the ring-shaped recess and the permanent magnet that excites this pole piece are provided, the magnetic fluid does not flow out into and out of the bearing oil tank, and further recovery and Refilling can be done easily. Therefore, maintenance and inspection is simple and can be completed in a short time, thus improving the economical efficiency. According to the third invention of the present application, since the magnetic fluid is filled in the ring-shaped recess engraved on the horizontal upper surface of the pole piece, the magnetic fluid does not flow out into and out of the bearing oil tank, and further recovery and Refilling can be done easily. Therefore, maintenance and inspection is simple and can be completed in a short time, thus improving the economical efficiency.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a shaft seal device for a bearing oil tank according to the first invention of the present application.

FIG. 2 is a sectional view showing an enlarged main part of the embodiment.

FIG. 3 is a cross-sectional view showing an embodiment of a bearing oil tank shaft seal device according to the second invention of the present application.

FIG. 4 is a cross-sectional view showing an embodiment of a bearing oil tank shaft seal device according to the third invention of the present application.

FIG. 5 is a sectional view showing a bearing device of a rotary machine using a conventional air-supply type shaft seal device.

FIG. 6 is a sectional view showing a bearing device of a rotary machine using a conventional magnetic fluid shaft seal device.

[Explanation of symbols]

 DESCRIPTION OF REFERENCE NUMERALS 1 rotary shaft of rotary machine 19 shaft seal device 20 magnetic fluid shaft seal device 21 air supply type shaft seal device 25 first air chamber 26 second air chamber 27 third air chamber 28 air supply pipe 29 exhaust pipe 30 horizontal flange portion 31 ring -Shaped recess 32 Magnetic fluid 33 Pole piece 33a One end of pole piece 35 Permanent magnet 38 Pole piece 39 Ring-shaped recess 40 Flange part 41 Hanging part 69 Bearing oil tank

Claims (4)

[Claims] 1. A shaft seal device for a bearing oil tank, which seals a rotating shaft of a rotating machine supported in oil in a bearing oil tank, wherein the shaft seal device is a magnetic fluid shaft seal device and an air supply type device arranged adjacent to each other. It consists of a shaft seal device,
A shaft seal device for a bearing oil tank, wherein the air supply type shaft seal device is located closer to the bearing oil tank than the magnetic fluid shaft seal device. 2. The air supply type shaft seal device comprises: a first air chamber adjacent to the magnetic fluid shaft seal device; a second air chamber adjacent to and in communication with the first air chamber; and a second air chamber. A third air chamber adjacent to and in communication with the chamber, an air supply pipe for supplying air having a higher pressure than the atmosphere in the bearing oil tank to the second air chamber, and an exhaust pipe connected to the third air chamber The shaft seal device for a bearing oil tank according to claim 1, comprising: 3. A bearing oil tank shaft seal device for sealing a rotating shaft of a rotary machine supported in oil in a bearing oil tank, wherein a horizontal upper surface of a ring-shaped horizontal flange portion projecting from the rotating shaft is provided. A ring-shaped recess formed in a circumferential shape so as to be concentric with the rotation axis, a magnetic fluid filled in the ring-shaped recess, and a magnetic fluid having one end in the ring-shaped recess A shaft seal device for a bearing oil tank, comprising: a pole piece immersed in a magnetic field; and a permanent magnet for exciting the pole piece. 4. A bearing oil tank shaft seal device for sealing a rotating shaft of a rotating machine supported in oil in a bearing oil tank, wherein a ring-shaped pole mounted on said bearing oil tank so as to surround said rotating shaft. A piece, a permanent magnet for exciting the pole piece, a ring-shaped recess carved in the horizontal upper surface of the pole piece so as to be concentric with the rotation axis, and the ring-shaped recess is filled. Magnetic fluid,
A ring-shaped flange portion protruding from the rotating shaft and located above the pole piece, and a hanging portion that hangs from an outer peripheral portion of the flange portion and a lower end thereof is immersed in the magnetic fluid in the recessed portion. A shaft seal device for a bearing oil tank.