JPH06331039A - Shaft seal device - Google Patents

Abstract

PURPOSE:To reduce leak liquid by applying pressure gas, adjustable to an arbitrary pressure associated with changing a pressure of objective sealed liquid, to gas and liquid annular spaces formed by a seal ring, so as to always fix a difference pressure of the seal ring. CONSTITUTION:In a shaft seal device used for an oil lubricating stern pipe bearing of a ship, seal rings 4 to 6 are fitted into a casing 3 so that the device is brought into slide contact with a liner 2 of inserting a shaft 1, to partition air annular space 7 between the seal rings 4, 5 and oil annular space 8 between the seal rings 5, 6. Here, an air back pressure equal to a draft equivalent pressure, detected by an air draft gage 15, is applied to an air relay 16 to serve as a pilot pressure, so as to apply an output pressure of this air relay 16 to the air annular space 7. In the oil annular space 8, an oil tank 10 is set up in a position where oil of pressure higher than the air pressure of the air annular space 7 can be applied. In this way, a load applied to the seal rings 4 to 6 is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shaft sealing device, and more specifically, it controls a pressure of a pressurized gas applied to a gas annular space in accordance with a change in pressure of a liquid to be sealed to thereby form a gas annular space. Keeping the differential pressure of the seal ring that constitutes the space small and constant at all times, reducing the load applied to the seal ring and extending the life, and at the same time collecting the liquid to be sealed and the liquid leaking to the gas annular space to the outside of the gas annular space. Accordingly, the present invention relates to a shaft sealing device that does not leak the liquid in the liquid annular space to the liquid to be sealed and does not allow the liquid to be sealed to enter the liquid annular space.

[0002]

2. Description of the Related Art Conventionally, a liquid ring-shaped space has been formed by appropriately arranging a plurality of liquid side seal rings to be sealed and a drive device side seal ring, which are in sliding contact with a shaft, in a casing loosely fitted to a shaft. The characteristic shaft sealing device is mainly used for oil-lubricated stern tube bearings of ships, and a lip type oil seal is generally used as a seal ring. In this case, the lip of the seal ring on the outside of the ship receives seawater pressure toward the seawater side, which is the liquid to be sealed, from the front of the lip, and the lip of another seal ring is used to seal the oil that is the liquid for lubricating the stern tube bearing. Is directed toward the stern tube bearing side and receives hydraulic pressure from the front of the lip. However, in the contact portion between the seal ring lip and the liner, the pressure on the back side is lower than the pressure on the front side, so that the leakage of oil to seawater cannot be avoided. Especially when the pressure of seawater is large, the sealing performance is reduced early due to the increase of the differential pressure applied to the seal ring. In addition, when the vibration of the shaft is large, a large amount of infiltration of oil into the oil annular space, which is the liquid annular space of seawater, and There have been problems such as a large amount of seawater leaking into the seawater.

For this reason, a system for automatically controlling the pressure of the oil annular space or one of the oil annular spaces as an air annular space in response to the pressure change of seawater, and the seawater leaking to the annular space or A shaft sealing device or the like having a mechanism for discharging oil to the outside of the annular space and collecting it has been used. One of them is to install a sensor such as a liquid level transmitter 30 near the axis shown in FIG. 5, detect a change in seawater pressure due to a change in draft, and convert this signal into air pressure by a differential pressure transmitter 32. It is known that the pressure regulator 33, the regulating valve 34 and the like are operated to regulate the pressure in the oil annular space 8. In addition, the applicant of the present invention applied for a utility model as a stern tube sealing device (Actual Application 63-43).
838, the actual opening 1-148171), the lip of the seal ring 4 on the most seawater side as shown in FIG.
On the seawater side, which is the 8th side, pressurized air controlled by the constant flow rate pressure control valve unit 18 is supplied to the air annular space 7 formed by directing the lips of the adjacent seal rings 5 toward the drive device side in the ship. The air pressure in the annular space 7 is taken out as a seawater pressure signal by releasing the pressurized air into the seawater from the lip of the seal ring 4 on the seawater side and communicating with the oil annular space 8 adjacent to the annular space 7. The pressure difference of the pressure fluctuation is controlled by controlling the pressure of the pressurized oil circulated by the oil pump P and installing the flow rate restricting device 19a on the upper part of the drain tank 9 communicating with the air annular space 7. At the same time as removing the seal ring 4,
There is also known a method of reducing the load applied to 5 and collecting seawater or oil leaked to the air annular space 7 into the ship.

[0004]

As a problem to be solved by the invention, one of the systems for automatically controlling the pressure of the oil annular space 8 in response to the pressure change of the seawater which is the liquid 28 to be sealed is A sensor such as a liquid level transmitter 30 is provided near the heart to detect a change in seawater pressure due to a change in draft, and this signal is converted into air pressure by a differential pressure transmitter 32 so that a pressure regulator 33, a regulating valve 34, etc. Is a method of adjusting the pressure of the annular space 8 by operating the above, but this method not only makes each device constituting the system extremely complicated and expensive, but also operates the adjusting valve 34 and the like in comparison with the change in seawater pressure. Therefore, the pressure difference in the annular space 8 does not always become constant, and a phase difference in pressure fluctuation occurs, causing leakage of oil or seawater.

In the system in which pressurized air controlled by the constant flow rate type pressure control valve unit 18 is put into the air annular space 7 and the pressurized air is discharged from the lip portion of the seawater side seal ring 4 into the seawater, the air annular space is used. Since there is almost no pressure fluctuation in the space 7, it is unlikely that the oil in the oil annular space 8 will leak to the seawater side in large quantities due to the phase difference, but the air in the annular space 7 will be removed in order to detect the seawater pressure. It is always necessary to release from the seal ring 4 into seawater. The air pressure in the annular space 7 is less than the seawater pressure near the liner 2 by a pressure difference corresponding to the tightening margin of the seal ring 4 itself and the tension of the garter spring 20 which decreases with time when the seal ring 4 is normal. Although it is always high, when the tightness of the seal ring 4 is almost eliminated, that is, the tightening margin due to the rubber of the seal ring 4 itself disappears due to secular change, and the garter spring 20 attached to the seal ring 4 is cut due to corrosion or the like. If the seal ring 4 is dropped or if an abnormality occurs in the seal ring 4 for some reason, the gap between the lip portion of the seal ring 4 and the liner 2 is further increased by air release, so that the seawater pressure is applied to the entire annular space 7. If the above-mentioned air flow rate is not supplied, the air is released and at the same time seawater enters the annular space 7. However, due to the characteristics of the constant flow rate pressure control valve unit 18, the annular space 7
It is not possible to take measures to reduce the amount of leakage by changing the pressure difference between the seal rings 4 by adjusting the pressure.

Since the constant flow rate pressure control valve unit 18 having the characteristic of constantly reducing the amount of air supplied to the annular space 7 to a constant flow rate is used, the air pipe 11 connected to the annular space 7 is used. When air leakage more than the amount of supplied air occurs in the drain pipe 12, the casing 3, etc., the pressure in the annular space 7 is reduced and the seal rings 4, 5
Since the pressure difference between the seal rings 4 and 5 increases, the load increases and the life of the seal rings 4 and 5 is significantly shortened. In order to know this state in advance, it is necessary to newly install a seawater pressure detection device, take out seawater pressure, detect the difference from the supply air pressure, and take a countermeasure.

Further, in the method of attaching a flow rate limiting device 19a to the upper portion of the drain tank 9 connected to the annular space 7 and discharging a small amount of air into the ship, a constant flow rate pressure control valve unit 18 is used to access the annular space 7. Since the amount of supplied air is limited, if the flow rate limiting device 19a is used for a long period with the opening thereof narrowed, the device 19a is blocked due to sticking due to mist and drain contained in the air, and the drain It may not be possible to collect them. Further, when oil leaks from the seal ring 5, there is also a drawback that the oil that cannot be collected as a drain from the annular space 7 leaks out of the ship together with the air blown to the seawater side to pollute the ocean. .

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and according to the present invention, a seal ring slidably contacting a shaft or a liner and a casing for holding the seal ring and surrounding the shaft or the liner. And a drive device-side seal ring adjacent to the liquid-side seal ring to be sealed to form a gas annular space, and the seal rings are appropriately arranged to form a liquid annular space and a gas annular space. In the shaft sealing device characterized in that,
The pressure of the liquid to be sealed is detected by an electric or differential pressure type liquid pressure detection device and converted into gas pressure, or the gas is discharged to the liquid to be sealed through a secondary pressure fluctuation type purge device which is a continuous bubble pressure detector. The output pressure of the air relay, which uses the back pressure, which is the gas pressure obtained by the above, as a signal pressure is applied to the gas annular space, and the liquid to be sealed and the liquid leaking into the gas annular space are recovered through the conduit to the outside of the gas annular space. Characterize.

Further, a flow restricting valve, an on-off valve or the like may be directly attached to the conduit, or the conduit may be branched and a drain recovery device may be provided at one end, and a primary pressure fluctuation type purging device may be provided at the other end or a conduit passing through the drain recovery device. An object of the present invention is to obtain a shaft sealing device having a flow rate limiting valve, an opening / closing valve, etc.

[0010]

Embodiments of the present invention will be specifically described below with reference to FIGS. In FIG. 1, seal rings 4 to 6 are fitted in the casing 3 from the outer side of the vessel toward the inner side of the vessel, and the lip portion of the seal ring 4 is sealed with the liquid to be sealed 28.
On the seawater side, the air annular space 7 is formed by arranging the lip portions of the adjacent seal rings 5 toward the drive device side in the ship, and the lip portions of the seal ring 5 and the seal ring 6 adjacent thereto are formed. The oil annular space 8 is formed by arranging the above toward the outside of the ship. At the stern of the hull, the discharge detected by discharging the supply air from the pneumatic draft meter 15 which is a pressure detector to the outside of the ship through the draft measuring pipe 14 having the discharge position to the outside of the light load draft line. The air back pressure for the air annular space 16 is operated with the air back pressure equal to the draft equivalent pressure at the position as the pilot pressure, and the output pressure of the air relay 16 is applied to the air annular space 7 via the air pipe 11. The oil tank 10 is a gravity tank that is open to the atmosphere and is attached to a position where a pressure higher than the air pressure of the air annular space 7 can be applied to the oil annular space 8. A needle valve 19, which is one of the flow rate limiting valves, is attached to a terminal of the drain pipe 12 that leads from the lower part of the air annular space 7 to the inside of the ship.

According to this structure, the pilot pressure can be increased or decreased by a predetermined amount by the characteristics of the air relay space air relay 16, and the air back pressure equal to the draft equivalent pressure from the pneumatic draft meter 15 can be directly applied. Since the air relay 16 is actuated, the pressure in the air annular space 7 has almost no operation delay with respect to the change in draft and can be adjusted to any pressure, so that it always changes with a constant differential pressure in conjunction with draft. Therefore, there is almost no phase difference in pressure fluctuation between the annular spaces, and the load on the seal ring 4 can be constantly small and constant. Even when a large amount of seawater leaks into the air annular space 7 due to an abnormality in the seal ring 4 or the like, the pressure in the air annular space 7 is made higher than the seawater pressure to blow air to the seawater side or lower it. Since it can be adjusted by applying a load and the like, it is possible to reduce the amount of leakage by changing the differential pressure of the seal ring 4. Liner 2
Since it is not necessary to constantly blow the air in the air annular space 7 to the seawater side from the lip portion of the seal ring 4 in order to detect the seawater pressure in the vicinity, when the pressure in the annular space 7 is adjusted to be lower than the seawater pressure. Even if the oil leaks from the seal ring 5, the oil does not leak out of the annular space 7 and all the leaked oil is collected in the ship through the drain pipe 12, so that the ocean is polluted. There is no such thing. Furthermore,
In this case, the air consumption is greatly reduced. The needle valve 19 is attached to the inboard end of the drain pipe 12 that communicates from the lower part of the air annular space 7 to the inside of the ship, and even if the drain is directly collected in the ship, the air amount is not throttled on the supply side. Since the pressure does not easily drop, the flow rate limiting device 19a
The drain tank 9 having the air vent pipe with the above attached is not required. Further, since the amount of air discharged from the needle valve 19 can be increased, it is unlikely that the drain cannot be recovered due to the blockage of the flow rate restricting device 19a. It can be easily seen by a decrease in the indicated value of the flow meter 35. Furthermore,
Since the piping resistance is reduced by simplifying the drain piping system,
Even if the draft changes, the drain of seawater or oil leaking into the air annular space 7 can be forcibly collected together with air to a position slightly lower than the light load draft line in the ship. The needle valve 19
Instead of an opening / closing valve such as a solenoid valve, a drain detector may be attached to the drain pipe 12 and the solenoid valve may be opened only when there is a drain.

In the oil annular space 8, when the set differential pressure of the seal ring 5 is insufficient with respect to the pressure fluctuation generated by the vibration of the shaft, and air leaks from the back surface of the seal ring 5 into the annular space 8, It can be easily seen by an increase in the indicated value of the air flow meter 35. Since the air amount is not throttled on the supply side of the air annular space 7, the annular space 7, the air pipe 11,
Even if air leakage occurs in the drain pipe 12 or the like, there is a margin until the pressure in the annular space 7 drops, and it can be easily detected by an increase in the indicated value of the air flow meter 35 of the air pipe 11. The increase in the load on the seal rings 4 and 5 can be easily known by, for example, providing a differential pressure gauge (not shown) between the pilot pressure and the output pressure pipes of the air relay 16 for the air annular space, so that the seal can be set beforehand. It is possible to prevent damage to the ring.

Next, in the embodiment shown in FIG. 2 for a ship having a large change in draft, in the case of FIG. 1, the pressure in the oil annular space 8 is always constant due to the gravity type oil tank 10 which is open to the atmosphere. The differential pressure of the seal ring 5, that is, the load largely fluctuates because the pressure of the air annular space 7 is interlocked with the change of the draft. For the purpose of preventing this, an oil tank air relay 17 having an air back pressure equal to the draft equivalent pressure of the draft measuring pipe 14 as a pilot pressure is provided, and the output pressure of the air relay 17 is connected to the oil annular space 8 by gravity. Oil tank 1 which is a pressure tank provided in place of the hydraulic oil tank 10
By adding 0a, the pressure in the oil annular space 8 changes in conjunction with the change in draft, so that the load on the seal ring 5 can always be made constant.

In FIGS. 1 and 2, when a drain valve 12 is attached directly to the terminal of the drain pipe 12 leading from the lower part of the air annular space 7 to the inside of the ship to collect the drain directly into the ship, the draft (seawater pressure) Since the pressure in the air annular space 7 also changes due to the change, the air flow rate fluctuates somewhat (for example, when the pressure in the air annular space 7 changes by 0.5 to 1.5 kg / cm ^{2, it} changes by about ± 10%). . In order to prevent this fluctuation, FIG. 3 shows a primary pressure fluctuation type purge device 2 that constantly discharges a fixed amount of air to the atmosphere regardless of fluctuations in seawater pressure.
1 is the other end of the drain pipe branching or the recovery device 9a
When air leaks from the back surface of the seal ring 5 to the oil annular space 8 by attaching it to the conduit passing through the upper part of the air ring space 7, the air annular space 7, the air pipe 11, the drain pipe 12
In the case where air leakage occurs due to, for example, an increase in the indicated value of the air flow meter 35, these are surely grasped, and the drain amount is monitored by the level meter of the drain recovery device 9a or the like. . When the air flow meter 35 is provided with a flow rate sensor and the drain recovery device 9a is provided with a liquid level monitoring sensor (neither is shown), the abnormality is further confirmed by an alarm.
You can easily know.

When the seawater-side seal ring 4 and the oil-side seal ring 5 are seriously damaged, the basic idea of the present invention is applied to a plurality of annular spaces by mounting the auxiliary seal rings 4a and 5a. FIG. 4 shows an embodiment intended to maintain the function of the shaft sealing device. Normally, the air relay 16 for the air annular space causes the air in the air annular space 7 to constantly leak from the rear surface of the seawater side preliminary seal ring 4a into the air annular space 7a, and the air in the annular space 7a does not blow out toward the seawater. By opening the valves of the air pipe 11, the drain pipes 12 and 12a in the open / closed state in the figure, and putting oil or the like into the air supplied to the annular space 7a by the lubricating oil supply device 25 in a state of dropping or mist. Since the air annular spaces 7 and 7a are provided on both the front and back sides, the progress of wear of the seal ring 4a and the liner 2 due to contact with the liner 2 in a dry state is prevented. Note that the oil collected from the lubricating oil supply device 25 to the drain tank 9a via the air annular space 7a is supplied again to the lubricating oil supply device 25.
You can put it in. Further, the oil side preliminary seal ring 5a is used in a state where no load is applied due to pressure adjustment of the oil tank air relay 17 and the oil tank. Even if the seawater-side seal ring 4 is damaged and emergency measures such as pressure adjustment by the air relay 16 for the air annular space are carried out and the leakage exceeds the drain recovery capability, the valves 26b and 26d are closed,
The valve 27 is opened to operate the seawater side preliminary seal ring 4a. Further, when the seawater-side preliminary seal ring 4a is damaged and the drain recovery capacity is exceeded even after performing the same emergency measures as described above, the valves 26, 26a to 26d and 27 are closed, and the valve 2 is closed.
7a and 27b are opened, and the oil annular space 8 is used as an air annular space. Seawater or oil leaked to the annular space is drain tank 9
Collect in a. When the oil-side seal ring 5 is damaged and the amount of oil leakage exceeds the allowable amount, the valves 26 and 26a are closed and the oil-side preliminary seal ring 5a is operated.

[0016]

In the shaft sealing device according to the present invention, a pressurized gas that can be adjusted to an arbitrary pressure linked to the pressure change of the liquid to be sealed is added to the gas annular space and the liquid annular space formed by the seal ring. As a result, the differential pressure of the seal ring is always kept small and constant, the load applied to the seal ring can be reduced, and the service life can be extended. Since there is almost no pressure fluctuation even if the shaft vibrates in the gas annular space, the liquid and liquid to be sealed do not move to each other due to the phase difference, and the liquid and liquid to be sealed leak into the gas annular space. However, it is recovered by the conduit outside the gas annular space. Moreover, since the pressure of the liquid to be sealed is not detected through the liquid seal ring on the liquid to be sealed, if the pressure in the gas annular space is adjusted to be lower than the pressure of the liquid to be sealed, even if the liquid in the liquid annular space leaks, the liquid will be sealed. There is no leakage into the target liquid, and air consumption is greatly reduced. In addition, since the pressurized gas supplied to the gas annular space is not throttled at the inlet side, there is a margin for leakage from the pressurized gas pipes, seal rings, etc., and abnormalities can be detected with a flow meter, differential pressure gauge, etc. It will be easy. As described above, the shaft sealing device of the present invention not only greatly improves the sealing performance and the state monitoring function, but also contributes greatly to pollution prevention, maintenance management, and economy. In the embodiment, the case where the lip type oil seal is arranged as the seal ring is shown, but the present invention arranges the limited leak type seal ring such as the segment seal and the floating seal and the mechanical seal as the seal ring. It can also be applied when It can also be applied to land-based shaft sealing devices that are used in the same way as stern tube shaft sealing devices.

[Brief description of drawings]

FIG. 1 is a schematic view of a stern tube shaft sealing device showing an embodiment of the present invention.

FIG. 2 is a schematic view showing an operating means in which the pressure of the liquid (oil) annular space is interlocked with the pressure change of the liquid to be sealed (seawater) in the embodiment of FIG.

FIG. 3 shows an operating means in which a drain recovery device for monitoring the amount of drain is attached in the embodiment of FIGS. 1 and 2, and the flow rate of the pressurized gas (air) is made constant with respect to the pressure change of the liquid to be sealed. It is a schematic diagram.

FIG. 4 is an embodiment in which the basic idea of the present invention is applied to a plurality of annular spaces by attaching respective preliminary seal rings to maintain the function as a shaft sealing device even when the seal rings are damaged. FIG. 3 is a schematic view of a stern tube shaft sealing device showing FIG.

FIG. 5 is a conventional liquid to be sealed (seawater) that does not use the present invention.
FIG. 3 is a schematic view of a stern tube shaft sealing device that automatically controls the pressure of a liquid (oil) annular space in response to the pressure change of FIG.

FIG. 6 is a diagram illustrating a conventional gas (air) annular space that does not use the present invention, in which a pressurized gas (air) controlled by a constant flow rate type pressure control valve unit is put into a liquid to be sealed (seawater) through a seal ring. It is a schematic diagram of a stern tube shaft seal device showing an operation means, such as discharging pressurized gas (air).

[Explanation of symbols]

 1 shaft 2 liner 3 casing 4, 4a, 5, 5a, 6 seal ring 7, 7a gas (air) annular space 8 liquid (oil) annular space 9, 9a drain recovery device (drain tank) 10, 10a oil tank 11 air Piping 12, 12a Drain piping 13 Oil piping 14 Draft measurement piping 15 Pressure detection device (air draft meter) 16 Air relay for gas (air) annular space 17 Air relay for liquid (oil) tank 18 Constant flow type pressure control unit 19, 19a Flow rate limiting device (needle valve) 21 Primary pressure fluctuation type purging device 25 Lubricating oil supply device 28 Sealing target liquid (seawater) 30 Liquid level transmitter 31 Liquid level transmission signal 32 Differential pressure transmitter 33 Pressure regulator 34 Regulator valve 35 Air flow meter

Claims (2)

[Claims] 1. A gas ring formed by a seal ring slidably contacting a shaft or liner, and a casing holding the seal ring and surrounding the shaft or liner, the liquid side seal ring to be sealed and a drive device side seal ring adjacent to the seal ring. A shaft-sealing device characterized by forming a space, and then arranging a seal ring appropriately to form a liquid annular space and a gas annular space, in which the pressure of the liquid to be sealed is an electric type, a differential pressure type liquid pressure detecting device, etc. The back pressure, which is the gas pressure obtained by releasing the gas into the liquid to be sealed through the secondary pressure fluctuation type purge device, which is a continuous bubble pressure detector, is used as the signal pressure. The output pressure of the air relay is applied to the gas annular space, and the liquid to be sealed and the liquid leaking to the gas annular space are recovered to the outside of the gas annular space by a conduit. Shaft sealing device. 2. A primary pressure fluctuation type purge is directly attached to the conduit, such as a flow control valve and an on-off valve, or a conduit is branched and one end is connected to a drain recovery device and the other end or a conduit passing through an upper part of the drain recovery device. The shaft sealing device according to claim 1, further comprising a device, a flow rate limiting valve, an on-off valve, and the like.