JPH107092A - Sealing device in emergency for stern tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely return a seal for emergency to an original condition when the seal for emergency is released by providing a vacuum pump on an air supply/discharge means, setting a wording chamber to be negative in pressure in an emergency release to secure a flow passage between the seal for emergency and a propeller shaft. SOLUTION: A working chamber 8 is formed by an annular groove on an outer circumferential surface of a seal 3 for emergency, and a pumping unit is connected through an air line 9. The pumping unit consists of a valve unit 25 comprising a compression pump 20, a pressure gage 21, two valves 22, 23, and a vacuum ejector 24. The vacuum ejector 24 is provided with a divergent nozzle, and the valves 22, 23 are simultaneously opened in an emergency release to operate the compression pump 20, and the air in the working chamber 8 is discharged through the valve 22, the pressure in the working chamber 8 becomes negative, and the seal 3 for emergency is returned to the casing 2 in a completely stored condition. Inconvenience that the seal for emergency is not returned to the original condition when the operation is released can be solved thereby.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stern tube emergency sealing device used as an auxiliary seal for a main seal in a stern tube shaft sealing device.

[0002]

2. Description of the Related Art In a stern tube shaft sealing device, when a main seal fails or during maintenance, an emergency seal provided on the stern side of the main seal is brought into close contact with a propulsion shaft so that seawater or the like enters the ship. Is temporarily prevented, during which time the main seal is repaired, replaced, or serviced.

FIG. 4 shows an example of a stern tube shaft sealing device provided with this kind of emergency sealing device. Stern tube body 1
An emergency seal 3 made of rubber is mounted between a partition 5 and a side plate 4 on a casing 2 fixed by bolts. Grease is applied to the surface of the side plate 4 and the partition wall 5 with which the emergency seal 3 contacts. Emergency seal 3
Is attached to the stern side on the left side of the figure with respect to the main seal 7 attached to the propulsion shaft 6, and its outer peripheral surface has
An operating chamber 8 is formed by the annular groove, and a pump device is connected to the operating chamber 8 through an air line 9. The pump device includes a compression pump 10, a pressure gauge 11, and a valve unit 15 including two valves 12 and 13.

[0004] Normally, the working chamber 8 is opened to the atmosphere by a valve 12 so that bearing cooling water 14 such as seawater can flow between the emergency seal 3 and the propulsion shaft 6. When the main seal 7 is out of order or in an emergency such as maintenance, as shown in FIG. 5, the valve 12 is closed and the valve 13 is opened, and compressed air is supplied to the working chamber 8 by the compression pump 10, so that the emergency seal The main seal 7 can be repaired, replaced, and maintained and inspected by closely adhering to the propulsion shaft 6 and preventing intrusion of seawater or the like from the stern side. When the repair or the like is completed, the valve 12 is opened and the valve 13 is closed again as shown in FIG. 4, the compressed air in the working chamber 8 is released to the atmosphere through the valve 12, and the emergency seal 3 and the propulsion shaft 6 are connected to each other. The bearing cooling water 14 and the like can flow between the spaces.

[0005]

However, in the above-mentioned conventional emergency seal device, if the emergency seal 3 is deteriorated due to aging or the like, the operation state shown in FIG. 5 is changed to the operation release state shown in FIG. When it is returned, the emergency seal 3 may not completely return as shown in FIG.
Such a situation may occur even if the emergency seal 3 is relatively new, even if the grease applied to the side plates 4 and the partition walls 5 on both sides thereof is washed away when the emergency seal is incorporated, or a marine organism or the like may be placed on the side of the emergency seal 3. It also occurs when adheres. If the emergency seal 3 does not return completely, the bearing cooling water 14 may not be sufficiently secured and the bearing may be damaged, or the emergency seal 3 may remain in contact with the propulsion shaft. In some cases, the inner peripheral surface of the emergency seal 3 and the propulsion shaft are worn, so that when the emergency seal 3 is operated, it is not possible to completely prevent intrusion of seawater or the like.

[0006] The present invention is to solve such a conventional problem, and when the emergency seal is deactivated,
It is an object of the present invention to provide a stern tube emergency sealing device that can always be returned to the original state.

[0007]

According to the present invention, in order to achieve the above object, when the emergency seal is deactivated, a negative pressure is introduced into the working chamber to forcibly return to the original state. Therefore, the problem caused by the emergency seal not returning to the original state can be solved.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, in an emergency, air is supplied to the working chamber to make the emergency seal adhere to the propulsion shaft. In a stern tube emergency seal device provided with air supply / exhaust means for ensuring airflow, a vacuum pump is provided in the air supply / exhaust means, and a negative pressure is applied to the working chamber at the time of emergency release, so that the flow between the emergency seal and the propulsion shaft The road was secured.

[0009]

FIG. 1 shows the construction of a stern tube shaft sealing device provided with an emergency sealing device according to one embodiment of the present invention. The overall configuration of the stern tube shaft sealing device is the same as the conventional example shown in FIG. 4, and the present embodiment differs from the conventional example in the configuration of the valve unit 25. In FIG. 1, reference numeral 1 denotes a stern tube main body, and a casing 2 is fixed by bolts. An emergency seal 3 made of rubber is attached to the casing 2 by a side plate 4 between the casing 2 and the partition wall 5. Grease is applied to the surface of the side plate 4 and the partition wall 5 with which the emergency seal 3 contacts. The emergency seal 3 is attached to the stern side on the left side of the main seal 7 attached to the propulsion shaft 6 in the drawing. An operating chamber 8 is formed on the outer peripheral surface of the emergency seal 3 by an annular groove, and a pump device 20 is connected to the operating chamber 8 through an air line 9. The pump device includes a compression pump 20, a pressure gauge 21, two valves 22 and 23, and a valve unit 25 including a vacuum ejector 24. The vacuum ejector 24 has a divergent nozzle, and makes the working chamber 8 a negative pressure according to the same principle as spraying. A normal vacuum pump may be used instead of the vacuum ejector 24.

Normally, the valve 2 of the valve unit 25
2 is opened, the valve 23 is closed, and the working chamber 8 is opened to the atmosphere by the valve 22. Therefore, the bearing cooling water 1 such as seawater is
4 can be distributed. When the main seal 7 breaks down or in an emergency such as maintenance, the valve 22 is closed and the valve 23 is opened as shown in FIG.
Compressed air is supplied to the working chamber 8 by a compression pump 20, and the emergency seal 3 is in close contact with the propulsion shaft 6 to prevent intrusion of seawater or the like from the stern side. Thereby, repair, replacement, and maintenance and inspection of the main seal 7 can be performed. When the repair or the like is completed, the valves 22 and 23 are then turned on as shown in FIG.
Are both opened and the compression pump 20 operates,
The air in the working chamber 8 is purged through the valve 22, the working chamber 8 becomes a negative pressure, and the emergency seal 3 is forced to the original state, that is, completely contained in the casing 2 as shown in FIG. The bearing cooling water 14 and the like can flow between the emergency seal 3 and the propulsion shaft 6.

As described above, according to the above embodiment, the vacuum ejector 24 having a simple structure and a low cost is used, and at the time of emergency release operation, the inside of the working chamber 8 is forcibly brought into a negative pressure state. 3 can be completely returned to its original state, the emergency seal 3 does not completely return to its original state, and thus the bearing may be damaged due to a shortage of cooling water, or the inner peripheral surface of the emergency seal or the propulsion shaft may be worn. It is possible to avoid a situation that occurs and the seal is incomplete at the time of emergency operation.

[0012]

As is apparent from the above embodiment, when the emergency seal is deactivated, a negative pressure is introduced into the working chamber to forcibly return the emergency seal to its original state. Thus, a problem caused by the emergency seal not being returned to the original state can be solved.

[Brief description of the drawings]

FIG. 1 is a partial sectional view of a stern tube shaft sealing device provided with an emergency sealing device according to an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view showing the operation of the stern tube emergency sealing device according to one embodiment of the present invention.

FIG. 3 is a partial sectional view showing the operation of the stern tube emergency sealing device according to one embodiment of the present invention.

FIG. 4 is a partial cross-sectional view of a stern tube shaft sealing device provided with an emergency sealing device in a conventional example.

FIG. 5 is a partial sectional view showing the operation of a conventional stern tube emergency sealing device.

FIG. 6 is a partial sectional view showing the operation of a conventional stern tube emergency sealing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Stern tube main body 2 Casing 3 Emergency seal 4 Side plate 5 Partition wall 6 Propulsion shaft 7 Main seal 8 Working chamber 9 Air line 10, 20 Compression pump 11, 21 Pressure gauge 12, 13, 22, 23 Valve 24 Vacuum ejector 15, 25 Valve unit

Claims (1)

[Claims] 1. An air supply / exhaust means for supplying air to a working chamber in an emergency to make an emergency seal adhere to a propulsion shaft, and discharging air from the working chamber to secure a flow path between the propulsion shaft and an emergency release in an emergency release. In a stern tube emergency seal device equipped with a vacuum pump in the air supply / exhaust means, and at the time of emergency release, a negative pressure is applied to the working chamber to secure a flow path between the emergency seal and the propulsion shaft. A stern tube emergency sealing device.