JP2011220465A - Shaft seal device - Google Patents

Abstract

An object of the present invention is to provide a shaft seal device capable of following the seawater pressure with the pressure in the annular chamber of the shaft seal device even when pressurized air cannot be supplied.
In a shaft seal device that seals a rolling bearing supporting a rotating shaft connected to a turbine blade of a tidal current power generation device from seawater, at least two seal rings are connected in an axial direction on a casing side that accommodates the rotating shaft. A shaft sealing device formed so as to contact and seal the surface of the rotary shaft side, and the annular chamber formed between the plurality of seal rings of the shaft sealing device is higher than the annular chamber in the sea An oil supply pipe connected to an oil reservoir tank installed at a position is connected, and the oil reservoir tank is formed so as to contract according to the pressure of seawater.
[Selection] Figure 4

Description

  The present invention relates to a shaft seal device suitable for a tidal current power generation device, and more particularly to a shaft seal device suitable for a tidal current power generation device including an oil-lubricated rolling bearing with low frictional resistance. The tidal current power generation device referred to in the present invention uses not only a tidal power generation device that uses tidal head energy and a power generation device that uses tidal energy that is constantly generated in every ocean, but also the flow of water in the river. The power generation device is also included. Accordingly, in the following description, “tide flow” includes river water flow, and “seawater” includes fresh water.

  Conventionally, in a tidal current power generation apparatus, a sliding bearing such as a rubber bearing or a resin bearing that employs a water lubrication system is known as a bearing that supports a turbine rotor (hereinafter referred to as “Prior Art 1”, for example, Patent Document 1). reference.). In addition, roller bearings are generally employed in those employing an oil lubrication system (hereinafter referred to as “Prior Art 2”, for example, see Patent Document 2).

The bearing in the water lubrication system of the prior art 1 described above has a problem that the power generation efficiency of the power generation device is lowered because the frictional resistance of the bearing is large.
On the other hand, since the roller bearing is adopted as the bearing in the oil lubrication system of the prior art 2, the frictional resistance of the rolling bearing can be reduced, but no measures are taken for the sealing of the rolling bearing. There is a risk of seawater entering. There is a problem in that seawater or the like enters the rolling bearing, the rolling bearing rusts and the roller does not rotate. Also, the oil that lubricates the rolling bearing must be prevented from leaking into the sea as much as possible. Considering this, a sealing device is indispensable in an oil lubrication system.

  A tidal current power generation device is a device that generates power by rotating a turbine blade using a tidal flow, and generally generates power by a tidal flow using a river or a tidal difference. When the tidal range is used, there are places where the tidal range exceeds 15m, so even if it is installed in a shallow sea, it is located at a deeper depth than the water surface at high tide. Under such a condition, the load applied to the seal ring becomes extremely excessive, so that a normal lip seal cannot be used.

  Furthermore, in a tidal current power generation device that generates power by rotating turbine blades using the tidal current, the friction between the bearings and the seal ring varies because the energy for rotating the turbine blades fluctuates and the size of the device increases. The resistance must be as small as possible. As a means for reducing the frictional resistance, an oil lubrication type rolling bearing is used for the bearing, and for the seal device, the fluid pressure between the seal rings can reduce the load acting on the seal ring. The system which makes it act is mention | raise | lifted.

The present applicant has filed a patent application for an invention of a shaft seal device (hereinafter referred to as “related invention”) suitable for sealing a bearing of an oil lubrication system of a tidal current power generation device.
FIG. 6 is a schematic diagram for explaining the overall configuration of the shaft seal device according to the related invention.
Four seal rings 18 are provided, and between the adjacent seal rings 18, a primary annular chamber 19, a secondary annular chamber 20, and a tertiary annular chamber 21 are formed around the liner 12 in order from the outside (seawater side). Has been.
An air supply pipe 31 of an air supply device 30 installed in the power generator main body is connected to the primary annular chamber 19.
The air supply device 30 includes an air supply source 29 installed on land, and an air control unit 40 provided between the air supply source 29 and the primary annular chamber 19. The air control unit 40 includes a pressure reducing valve 41 and a flow rate adjusting valve 42.
The air control unit 40 including the pressure reducing valve 41 and the flow rate adjusting valve 42 performs a mechanical operation based on the fluctuation of the seawater pressure although the fluctuation of the air supply amount occurs when the seawater pressure changes. There is no uncontrolled interlocking type.

  Further, an oil supply pipe 33 for connecting the oil reservoir tank 32 and the secondary annular chamber 20 is provided so that the lubricating oil can be supplied to the secondary annular chamber 20 from the oil reservoir tank 32 installed at a predetermined height in the power generator main body. It is done. Connected to the oil reservoir tank 32 is an internal pressure sensing pipe 34 branched from the middle of the air supply pipe 31 of the air supply device 30. The height at which the oil reservoir tank 32 is installed is set such that a head pressure higher than the pressure in the primary annular chamber 19 by a predetermined magnitude can be applied to the secondary annular chamber 20. For example, by installing the oil reservoir tank 32 at a position 2 to 4 m higher than the shaft seal device 10, the pressure required for blowing air from the primary annular chamber 19 to the outside of the ship (seawater side) is changed to the secondary annular chamber. It can be given to an internal pressure of 20.

  The fluid pressure from the air supply pipe 31 acts on the oil level in the oil reservoir tank 32 via the internal pressure sensing pipe 34. However, since the air supply pipe 31 communicates with the primary annular chamber 19, the oil reservoir tank is eventually obtained. Since the pressure that changes synchronously with the change in the internal pressure of the primary annular chamber 19 and the time delay does not act on the oil surface in 32, as a result, the internal pressure of the secondary annular chamber 20 is always higher than the seawater pressure. Only the head pressure of 32 lubricating oil increases.

In the shaft seal device 10 having such a configuration, the primary annular chamber 19 is supplied to the primary annular chamber 19 within the range of the set value of the pressure reducing valve 41 and the set value of the flow rate control valve 42 in the air control unit 40 by the seawater pressure Air is supplied so that the internal pressure obtained by adding the ring tightening pressure to Pa is maintained.
On the other hand, in the secondary annular chamber 20, a pressure obtained by adding the head pressure of the lubricating oil corresponding to the height of the oil reservoir tank 32 is applied in addition to the internal pressure obtained by adding the ring tightening pressure to the seawater pressure Pa.
Therefore, the air supplied to the primary annular chamber 19 is always blown out to the seawater side.

Special table 2008-513650 gazette JP 2002-242811 A

If the tidal power generation device can be installed near the coast, air can be continuously supplied from the land, but the tidal power generation device is not always installed near the coast. For example, it may be installed several kilometers away from the coast. In such a case, since continuous supply of air from the land becomes impossible, it is difficult to employ an air seal type shaft seal device that continuously supplies air from the land as in the related invention shown in FIG. Become.
When air cannot be supplied to the annular chamber between the seal rings, there is a problem that the load applied to the seal rings becomes large and the life of the seal rings is shortened.
In addition, if air pressure cannot be applied to the oil reservoir tank, the hydraulic pressure in the secondary annular chamber cannot follow the seawater pressure fluctuation, so the hydraulic pressure in the secondary annular chamber becomes lower than the seawater pressure. When the seal ring is damaged, seawater enters the chamber in which the rolling bearing is installed, causing a problem that the rolling blade is damaged and the turbine blade of the tidal current power generator cannot be rotated.

In view of such a situation, when the air seal method is adopted, it is necessary to attach an air source to the tidal current power generation device itself. In this case, the amount of air consumption must be minimized for maintenance.
The pressure reducing valve 41 used in the related invention is called a relief type pressure reducing valve that leaks air on the secondary side inside the valve and releases the secondary pressure when the secondary pressure exceeds a set value. There was a problem that air consumption was large.

A first object of the present invention is to provide a shaft seal device that can follow the pressure of the annular chamber of the shaft seal device to the seawater pressure even when pressurized air cannot be supplied.
A second object of the present invention is to provide a shaft seal device that minimizes the amount of air consumption even when an air seal system is employed in the shaft seal device.

  In order to achieve the above object, a shaft seal device according to the present invention is, firstly, a shaft seal device that seals a rolling bearing that supports a rotation shaft connected to a turbine blade of a tidal current power generation device from seawater, and accommodates the rotation shaft. A shaft sealing device is provided on the casing side, and at least two seal rings are connected in the axial direction so as to contact and seal the surface of the rotating shaft side, and a plurality of seal rings of the shaft sealing device are provided between the seal rings. The formed annular chamber is connected to an oil supply pipe connected to an oil reservoir tank installed at a position higher than the annular chamber in the sea, and the oil reservoir tank is formed to contract according to the pressure of seawater. It is characterized by that.

  According to the first feature described above, even when pressurized air cannot be supplied, the pressure in the annular chamber to which the oil supply pipe is connected can be made to follow the seawater pressure and maintained at a pressure obtained by adding the ring tightening pressure to the seawater pressure. Therefore, the load on the seal ring can be reduced, and seawater can be prevented from entering the room in which the rolling bearing is installed.

  The shaft seal device of the present invention is secondly a shaft seal device that seals a rolling bearing supporting a rotating shaft connected to a turbine blade of a tidal current power generation device from seawater, on a casing side that accommodates the rotating shaft. A shaft seal device is provided in which at least three seal rings are arranged in parallel in the axial direction so as to contact and seal the surface on the rotary shaft side, and are formed between a plurality of seal rings of the shaft seal device. Of the plurality of annular chambers, the first annular chamber from the seawater side is supplied with air from an air source provided in the casing so that the inner pressure obtained by adding the ring tightening pressure to the seawater pressure is maintained. The device is connected, and the second annular chamber from the seawater side is connected with an oil supply pipe connected to an oil reservoir tank installed at a position higher than the annular chamber in the sea. To shrink It is characterized in that have been made.

  Due to the second feature described above, the pressures in the first and second annular chambers from the seawater side while minimizing the amount of air consumption even in installation locations where continuous supply of pressurized air from the land is not possible. Can follow the seawater pressure and maintain the pressure of the seawater pressure plus the ring tightening pressure, reducing the load on the seal ring and preventing seawater from entering the room where the rolling bearings are installed. Can do.

The present invention has the following excellent effects.
(1) In the first feature, an oil supply pipe connected to an oil reservoir tank installed at a position higher than the annular chamber in the sea is connected to an annular chamber formed between a plurality of seal rings. Since it is configured to shrink according to the pressure of seawater, even when pressurized air cannot be supplied, the pressure in the annular chamber can be made to follow the seawater pressure, so the load on the seal ring can be reduced. Intrusion of seawater into the room in which the rolling bearing is installed can be prevented.

(2) In the second feature, air is supplied to the first annular chamber from the seawater side from an air source provided in the casing so that an internal pressure obtained by adding a ring tightening pressure to the seawater pressure is maintained. An air supply device is connected, and the second annular chamber from the seawater side is connected to an oil supply pipe connected to an oil reservoir tank installed at a position higher than the annular chamber in the sea. In the installation place where the continuous supply of pressurized air from the land is impossible, the first and second from the seawater side while minimizing the amount of air consumption. The pressure in the annular chamber can be made to follow the seawater pressure and the pressure of the seawater pressure plus the ring tightening pressure can be maintained, reducing the load on the seal ring and intruding seawater into the room where the rolling bearings are installed. It is possible to prevent.

It is a perspective view which shows the whole structure of the tidal power generation apparatus with which the shaft seal device which concerns on embodiment of this invention is mounted | worn. FIG. 2 is a cross-sectional view of a tidal current power generator main body composed of the turbine blades and the like of FIG. It is an expanded sectional view of the shaft seal device of FIG. It is a schematic diagram for demonstrating the whole structure of the shaft seal apparatus which concerns on Embodiment 1 of this invention. It is a schematic diagram for demonstrating the whole structure of the shaft seal apparatus which concerns on Embodiment 2 of this invention. It is a schematic diagram for demonstrating the whole structure of the shaft seal apparatus of related invention.

  The embodiment for carrying out the shaft seal device of the present invention will be described in detail with reference to the drawings. However, the present invention is not construed as being limited to this, and unless the scope of the present invention is deviated, Various changes and improvements can be made based on the knowledge of the traders.

[Embodiment 1]
FIG. 1 is a perspective view showing an overall configuration of a tidal current power generation device to which a shaft seal device according to an embodiment of the present invention is attached.
FIG. 2 is a cross-sectional view of a tidal current power generation device main body composed of the turbine blades of FIG.

In FIG. 1, the tidal current power generation device is a subsurface flow W in a sea below a sea surface 3 by a support structure 2 erected from the seabed 1 in a sea where a horizontal current W as a tidal current or a sea current such as a strait is generated. The tidal power generation device main body 5 composed of the turbine blades 4 and the like disposed so as to face the support structure 2 is provided on both sides of the support structure 2.
In the tidal current power generator main body 5 shown in FIG. 1, the turbine blade 4 is provided only on the upstream side, but this is also provided on the downstream side, and the power generator is driven by the upstream and downstream turbine blades 4 respectively. You may make it do.

As shown in FIG. 2, the tidal current power generator main body 5 mainly includes a turbine blade 4, a rotating shaft 6 that is connected to the turbine blade 4 and rotated, a rolling bearing 7 that supports the rotating shaft 6, and a rotating shaft 6. A power generation device 8 that is driven to rotate, generates power, a rotary shaft 6, a rolling tank 7, a hollow tank-shaped casing 9 that houses and holds the power generation device 8, and the like, and seawater enters between the casing 9 and the rotary shaft 6 in the casing 9. It is comprised from the shaft seal apparatus 10 which seals so that it may not enter. The casing 9 is provided so as to cover the rotary shaft 6 with a space between the turbine blade 4 and a shaft seal device 10 is provided around the rotary shaft 6 between the turbine blade 4 and the casing 9. Further, the downstream end of the casing 9 is formed in a streamline shape. Further, the casing 9 is supported by a support member 11 extending from the support structure 2, and is fixed to the support member by, for example, welding.
In the case where the turbine blade 4 is also provided on the downstream side, the rotary shaft 6, the rolling bearing 7, the power generation device 8, and the shaft seal device 10 are also arranged at the downstream extended position symmetrically with these upstream members. The
Further, the power generation device 8 can be installed on the support structure 2 without being arranged in the casing 9, and in this case, the power of the rotating shaft 6 is supported via the gear mechanism and the transmission shaft. 2 is guided to the power generation device 8 installed in the vehicle 2.

The turbine blade 4 is rotated by receiving the kinetic energy of the tidal current, and the power generation device 8 generates power by transmitting the rotation of the turbine blade 4 to the power generation device 8 through the rotation shaft 6. The generated electricity is transmitted, for example, by a power cable or the like disposed from the inside of the support structure 2 toward the power demand side via the support member 11.
Further, the lubricating oil can be supplied to the rolling bearing 7 through a pipe or the like disposed inside the support structure 2. Thus, since the inside of the casing 9 provided with the rolling bearing 7 is an air chamber communicated with the atmosphere, and the pressure in the casing 9 is atmospheric pressure, if the shaft seal device 10 is damaged, the casing 9 The pressure conditions are such that seawater can easily enter.

As shown in FIGS. 2 and 3, a shaft seal device 10 is provided around the rotating shaft 6 between the turbine blade 4 and the casing 9. In the case of this example, a high-chromium / stainless steel liner 12 is disposed on the outer periphery of the rotary shaft 6 provided with the shaft seal device 10, and the liner 12 is bolted to the turbine blade 4 via an O-ring 13. It is fixed with. The shaft seal device 10 is supported and fixed to the flange 14 of the casing 9 so as to be in contact with the outer peripheral surface of the liner 12.
As shown in an enlarged view in FIG. 3, the shaft seal device 10 includes a flange ring 15 fixed to the flange 14 of the casing 9 by fixing means such as bolts, a plurality of intermediate rings 16, and an outermost cover ring 17. And at least four seal rings 18, and the flange ring 15, the intermediate ring 16 and the cover ring 17 are combined by bolts (not shown), and the seal ring 18 is fastened and fixed between these rings 15, 16, 17. Has been. The seal ring 18 is made of fluorine rubber, nitrile rubber, or the like, and has a “<” shape in cross section so that it can follow the movement of the liner 12. Further, when a predetermined pressure is applied to the seal ring 18, the flange ring 15, the intermediate ring 16 and the cover ring 17 are backed up so as to support this from the back, and the contact width between the seal ring 18 and the liner 12 is always kept constant. It is like that.

  The size of the tidal current power generation device varies depending on the power generation capacity and the like. For example, the outer diameter of the liner 12 to which the shaft seal device 10 is attached is about 20 to 30 cm. The pressure received from seawater does not change much between the upper part and the lower part of the sealing device 10.

FIG. 4 is a schematic diagram for explaining the overall configuration of the shaft seal device according to the first embodiment.
In the first embodiment, four seal rings 18 are provided. Between the adjacent seal rings 18, a primary annular chamber 19, a secondary annular chamber 20, and a tertiary annular chamber 21 are formed around the liner 12 in order from the outside (seawater side).
In the following, for the convenience of explanation, the “first seal 22”, “second seal 23”, “third seal 24”, and “fourth” in order from the outermost seal ring 18 toward the inner side. This is referred to as “seal 25”. That is, the primary annular chamber 19 is formed by the first seal 22 and the second seal 23, the secondary annular chamber 20 is formed by the second seal 23 and the third seal 24, and the tertiary annular chamber 21 is the third seal 24. And the fourth seal 25 is formed.

  The first seal 22, the third seal 24, and the fourth seal 25 have their front surfaces (sides that increasingly press the lip portion against the outer surface of the liner 12 to be sealed) when subjected to fluid pressure. On the contrary, the second seal 23 is arranged so that the front face thereof faces inward. For this reason, when a fluid force acts in the primary annular chamber 19, the lip portion is deformed so as to open on both sides, and conversely, when a fluid pressure acts in the secondary annular chamber 20, the lip portion becomes the surface to be sealed. It deform | transforms so that it may press on the outer surface of the liner 12 which is.

In FIG. 4, an oil reservoir tank 38 installed at a position higher than the annular chambers 19, 20, 21 is provided in the seawater outside the power generator main body 5, and the oil reservoir tank 38 leads to the secondary annular chamber 20. An oil supply pipe 33 that connects the oil reservoir tank 38 and the secondary annular chamber 20 is provided so that lubricating oil can be supplied.
The oil reservoir tank 38 has a sealed structure so that seawater does not enter, and is formed so as to contract under the pressure of seawater from the outside. As the structure of the oil reservoir tank 38, for example, the shape is a rectangular parallelepiped, and the bottom surface is made of stainless steel to give rigidity, and the other surface is formed of a flexible material such as a rubber film. The bottom and top surfaces of the shape must be rigid, the side surface can be accordion-like and can be shrunk in the vertical direction, the shape can be spherical, and the whole can be made of a flexible material such as rubber. Etc.
As the lubricating oil, it is desirable to use biodegradable oil in consideration of leaking out of the apparatus.

The oil reservoir tank 38 receives pressure from seawater according to the installation depth and contracts to push out the internal oil, so that the secondary annular chamber can be used without continuously supplying air to the oil reservoir tank 38. Since the hydraulic pressure in 20 follows fluctuations in seawater pressure, the load on the seal ring is reduced and seawater can be prevented from entering the room where the rolling bearing 7 is installed.
The installation height of the oil reservoir tank 38 is not particularly limited, but it is preferable to install it in the vicinity of the upper portion of the secondary annular chamber 20 in order to make the oil supply pipe 33 as short as possible.
In the shaft seal device of the first embodiment shown in FIG. 4, four seal rings 22, 23, 24, and 25 are disposed. This is a severe condition in which the third seal ring 24 has a large pressure difference. No. 2 seal ring 23 has a small pressure difference, but the back side of the seal ring is water (seawater) and the lubrication state is poor. Further, foreign matter such as fishing nets in seawater is caught in the seal ring and is easily damaged. In addition, a first seal ring 22 and a fourth seal ring 25 are provided to make up for the respective problems. That is, if the No. 1 seal ring 22 and the No. 4 seal ring 25 are not provided, the back side of the No. 2 seal ring 23 is exposed to seawater and is in a poorly lubricated state, and in addition, it is damaged by the inclusion of foreign matter in the seawater. In addition to the excessive pressure difference, the No. 3 seal ring 24 is exposed to air on the back side, so the lubrication state is poor, and the temperature of the sliding surface may increase and damage may occur. A number seal ring 22 and a number 4 seal ring 25 are provided, and lubricating oil is preliminarily sealed in the primary annular chamber 19 and the tertiary annular chamber 21. The first seal ring 22 has the role of protecting the second seal ring 23 from foreign matter in seawater at the same time as sealing the seawater with the front side of the seal ring facing the seawater side. Thus, increasing the number of seal rings is desirable in terms of the sealing function, but considering the installation space and cost, it is desirable that the number of seal rings is small. In the present embodiment, the first seal ring 22 and the fourth seal ring 25 are desirable but not essential, and the first embodiment may be omitted even if the first seal ring 22 and the fourth seal ring 25 are omitted. Needless to say, the object of the invention can be achieved. Therefore, the minimum necessary number of seal rings in the invention according to Embodiment 1 is two.

[Embodiment 2]
FIG. 5 is a schematic diagram for explaining the overall configuration of the shaft seal device according to Embodiment 2 of the present invention. Since the tidal current power generation device to which the shaft seal device according to the second embodiment of the present invention is attached is the same as that shown in FIGS. 1, 2, and 3 in the first embodiment, the description thereof is omitted.
Moreover, since the same code | symbol as the code | symbol of Embodiment 1 means the same member, those description is also abbreviate | omitted.

In FIG. 5, the shaft seal device 10 includes an air supply device 30, and an air supply pipe 31 of the air supply device 30 is connected to the primary annular chamber 19.
The air supply device 30 includes a high pressure air tank 26 as an air supply source, and an air control unit 27 provided between the high pressure air tank 26 and the primary annular chamber 19. The air control unit 27 has a pressure reducing valve 28 and a flow rate adjusting valve 42. The high-pressure air tank 26 is fixed at an appropriate position on the casing 9 side.

The pressure reducing valve 28 is a relief type that discharges air from the relief hole of the diaphragm when the secondary side pressure becomes higher than a set value (for a relief type pressure reducing valve, see, for example, Japanese Utility Model Publication No. 6-86104). In addition, a non-relief type pressure reducing valve that does not release air to the outside from the pressure reducing valve is employed to reduce air consumption.
The reason why the non-relief type pressure reducing valve can be used in the present invention is as follows.
The basic operation of what is generally called a pressure reducing valve is to maintain the fluctuating pressure (secondary pressure) at a set value when a pressure fluctuation occurs on the downstream side of the secondary port. However, assuming that the secondary port of the pressure reducing valve is released to the atmosphere, the secondary pressure becomes equal to the atmospheric pressure immediately after being discharged from the pressure reducing valve, regardless of the setting of the pressure reducing valve. .
On the other hand, the pressure reducing valve 28 used in the present invention has its secondary port opened to the primary annular chamber 19 via the air supply pipe 31, so the secondary pressure of the pressure reducing valve 28 is It becomes equal to the total value obtained by adding the tightening pressure of the seal rings 22 and 23 to the seawater pressure. That is, in the pressure reducing valve 28, the upper limit of the secondary side pressure (= internal pressure of the primary annular chamber 19) is only set in accordance with the seawater pressure accompanying the maximum flooding, and this is set once. In other words, the pressure reducing valve 28 does not need to be controlled at all due to fluctuations in seawater pressure.

  As the air control unit 27 having the pressure reducing valve 28 and the flow rate adjusting valve 42, that is, the air supply device 30 including the air control unit 27 and the high-pressure air tank 26, At the time of fluctuation, the air supply amount changes accordingly, but the mechanical operation based on the fluctuation of the seawater pressure is not performed, and it is an uncontrolled interlocking type.

On the other hand, the oil supply pipe 33 is connected to the bottom of the oil reservoir tank 38 installed at a position higher than the annular chambers 19, 20, 21 in seawater as described in Embodiment 1 in FIG. The secondary annular chamber 20 is supplied.
The oil reservoir tank 38 has a sealed structure so that seawater does not enter, and is formed so as to contract under the pressure of seawater from the outside.
The oil reservoir tank 38 receives pressure from seawater according to the installation depth and contracts to push out the internal oil, so that the secondary annular chamber can be used without continuously supplying air to the oil reservoir tank 38. Since the oil pressure of 20 follows the seawater pressure even when the seawater pressure fluctuates, the load on the seal ring is reduced and seawater can be prevented from entering the bearing chamber.
A check valve 37 is provided in the vicinity of the air control unit 27 of the air supply pipe 31 so that the lubricating oil does not flow to the air control unit 40 side.

The shaft seal device 10 having such a configuration operates as follows.
Now, for example, the air pressure in the high-pressure air tank 26 is 3 MPa. The high-pressure air tank 26 and the air control unit 27 are connected to reduce the pressure of the air source and set the air consumption. For example, the supply pressure to the primary annular chamber 19 is reduced at 0.5 MPa, and the air consumption is set to 100 cc / min.
In the primary annular chamber 19, an internal pressure obtained by adding the ring tightening pressure to the seawater pressure Pa is held by the air supply device 30 within the range of the set value of the pressure reducing valve 28 and the set value of the flow rate adjusting valve 42 in the air control unit 27. Air will be supplied as is done.
The apparatus according to the related invention uses a relief type pressure reducing valve, which consumes a large amount of air. However, in this embodiment, a non-relief type pressure reducing valve is used, so that the air consumption can be considerably reduced.

  On the other hand, since the oil reservoir tank 38 connected to the secondary annular chamber 20 has a contractible structure, the lubricating oil in the oil reservoir tank 38 is pressurized according to the seawater pressure. That is, the pressure in the secondary annular chamber 20 can follow the fluctuation of the seawater pressure without continuing to supply air to the oil reservoir tank 38.

  In the shaft seal device of the second embodiment shown in FIG. 5, four seal rings 22, 23, 24, 25 are arranged. This is because the third seal ring 24 has a pressure difference of one. Since the operation is performed under the severest conditions, the 4th seal ring 25 is provided in order to improve the lubrication state of the 3rd seal ring 24. That is, if the No. 4 seal ring 25 is not provided, the back side of the No. 3 seal ring 24 is exposed to air and the lubrication state is poor, and the temperature of the sliding surface may be increased and may be damaged. A seal ring 25 is provided, and lubricating oil is sealed in the tertiary annular chamber 21 in advance. Thus, increasing the number of seal rings is desirable in terms of the sealing function, but considering the installation space and cost, it is desirable that the number of seal rings is small. In the present embodiment, the fourth seal ring 25 is desirable but not essential, and it goes without saying that the object of the invention according to the second embodiment can be achieved even if the fourth seal ring 25 is omitted. Absent. Therefore, the minimum number of seal rings in the invention according to Embodiment 2 is three.

Further, when the pressure difference between the water pressure (seawater pressure) and the chamber (inside the casing) in which the bearing is installed becomes large, the third seal ring is connected by connecting an oil reservoir tank to the tertiary annular chamber 21 and applying pressure. It is also possible to reduce the load of 24. At that time, when the load on the fourth seal ring 25 is increased, damage to the seal ring can be prevented by sequentially adding the seal ring 18 to the chamber side where the bearing is installed. It goes without saying that the direction of the seal ring can be changed according to the conditions. Further, the oil reservoir tank 38 only needs to have a function of contracting under seawater pressure, and the material and structure are not limited to those described above.
Furthermore, in the shaft seal device of the second embodiment, the air supply device 30 configured to include the air control unit 40 including the pressure reducing valve 41 and the flow rate adjusting valve 42 and the air supply source 29 is provided. Although the fluctuation of the air supply amount associated with the fluctuation of the seawater pressure occurs, the case of using the uncontrolled interlocking type that does not perform the mechanical operation based on the fluctuation of the seawater pressure is explained. What is essential is that the pressure relationship of (seawater pressure Pa) <(inner pressure of the primary annular chamber 19) is always formed even if the seawater pressure fluctuates. An air supply device having a control valve may be used.

  As shown in FIGS. 4 and 5, near the bottom of the casing 9, a liquid level sensor 35 and a drainage pump 36 that operates by sensing the liquid level sensor 35 are mounted. Should seawater enter the casing 9, the liquid level sensor 35 detects this and discharges the seawater by the operation of the drainage pump 36 to prevent the seawater from reaching the rolling bearing 7 or the like.

DESCRIPTION OF SYMBOLS 1 Seabed 2 Support structure 3 Sea surface 4 Turbine blade 5 Tidal current power generator main body 6 Rotating shaft 7 Rolling bearing 8 Power generator 9 Casing 10 Shaft seal 11 Support member 12 Liner 13 O-ring 14 Flange 15 Flange ring 16 Intermediate ring 17 Cover ring 18 Seal ring 19 Primary annular chamber 20 Secondary annular chamber 21 Tertiary annular chamber 22 1st seal 23 2nd seal 24 3rd seal 25 4th seal 26 High pressure air tank 27 Air control unit 28 Pressure reducing valve 30 Air supply device 31 Air supply pipe 33 Oil supply pipe 35 Liquid level sensor 36 Drain pump 37 Check valve 38 Oil reservoir tank 42 Flow control valve

Claims (2)

  In a shaft seal device for sealing a rolling bearing supporting a rotating shaft connected to a turbine blade of a tidal current power generator from seawater, at least two seal rings are axially connected to a casing side housing the rotating shaft, and the rotating shaft A shaft seal device formed to contact and seal the side surface is provided, and the annular chamber formed between the plurality of seal rings of the shaft seal device is installed at a higher position in the sea than the annular chamber. An oil supply pipe connected to the oil reservoir tank is connected, and the oil reservoir tank is formed so as to contract according to the pressure of seawater. In a shaft seal device that seals a rolling bearing that supports a rotating shaft connected to a turbine blade of a tidal current power generator from seawater, at least three seal rings are arranged in parallel in the axial direction on the casing side that accommodates the rotating shaft. Provided with a shaft sealing device formed to contact and seal the shaft side surface, and among the plurality of annular chambers formed between the plurality of seal rings of the shaft sealing device, the first ring from the seawater side The chamber is connected to an air supply device that supplies air from an air source provided in the casing so that the internal pressure obtained by adding the ring tightening pressure to the seawater pressure is connected to the second annular chamber from the seawater side. Is an oil supply pipe connected to an oil tank installed at a position higher than the annular chamber in the sea, and the oil tank is formed so as to contract according to the pressure of seawater. Seal Location.

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