JPH0645439Y2 - Stern tube sealing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a stern tube seal device used for an oil-lubricated stern tube bearing, and more specifically, a plurality of seals whose pressure surface faces the seawater side. The present invention relates to an improvement of a stern tube sealing device in which a plurality of seal rings are arranged with a ring on the propeller side and a pressure surface on the stern tube bearing side.

(Prior Art) Since oil-lubricated stern tube bearings were adopted for large tankers Negishi Maru in Japan in 1964, they have become widely used with the increase in size of ships. Although it uses lubricated bearings and sealing devices, the stern tube sealing device uses a rubber lip-type seal ring for sealing seawater and oil, so even today, after 20 years, Even if it is said to be less than in the past, the damage to the seal ring will be less, and it is the current situation in terms of maintenance and pollution of ships. Among these, Japanese Patent Publication Sho 56-8221
The seal device disclosed by JP-A No. 6-31240 is stored as a spare seal ring by equalizing the pressures of the front space and the back space of the seal ring located closest to the stern tube bearing side, and when the adjacent seal ring is damaged. In addition, it is widely used in the system in which the spare seal ring is actually operated by adjusting the adjusting valve. At the same time, however, pressure fluctuations in the annular chamber between the seal rings due to vertical and horizontal vibrations of the propeller shaft are complicated, so it is difficult to maintain equal pressures on the front and back sides of the seal ring. I can not say that a considerable differential pressure is being applied.In addition, since the rubber seal ring itself has a tracking force, and it works in the direction to tighten the shaft with the garter spring, even if I think that I made it the same pressure. Actually, the shaft and the seal ring always slide under pressure, and the shaft and the seal ring tend to be worn.
It is also confirmed in the result of the open inspection of the sealing device. In addition, as disclosed in the specification of the above-mentioned publication, "it may be damaged at all even if it is used with a small differential pressure, so that it can serve as a spare seal ring." There is a drawback of "not".

(Object and Structure of the Invention) The present invention was made to solve the above-mentioned drawbacks.
In a word, by making the pressure on the back side of the seal ring slightly higher than that on the front side (about 0.1 Kg / cm ² ), the sliding surface of the seal ring is always lifted from the shaft and actively The basic technical idea is to maintain the non-contact state. According to the present invention, a stern tube sealing device in which the pressure surfaces of a plurality of seal rings on the stern side are arranged on the seawater side and the pressure surfaces of a plurality of seal rings on the bow side are arranged on the stern tube bearing side is used. A stern tube gravity tank is installed near the line height, and a pressure tank for an annular chamber composed of two seal rings arranged closest to the stern tube bearing side is installed at a position higher than this, from each of them. By connecting the pressure supply pipes so that the annular chamber pressure can be circulated higher than the pressure in the stern pipe, the pressure tanks are connected so that the pressure difference between the pressure tanks is always the most. A stern tube sealing device can be obtained in which the seal ring near the stern tube side floats and can maintain a non-contact state. Further, according to the present invention, one pressure tank is provided so that the pressure supply pipe of the gravity tank for the stern tube is branched and communicated with the annular chamber, and a constant flow rate control type pressure control device is arranged at an appropriate position on the way to obtain a constant difference. Pressure oil at pressure can also be supplied to the annular chamber.

(Embodiment) Hereinafter, a stern tube sealing device according to the present invention will be described with reference to two embodiments shown in FIGS. 1 and 2. In the following figures, the same numbers indicate the same names. 1, 2,
3, 4 are seal rings held by the housing member 5 of the stern tube seal 10 and slidingly contacting the propeller shaft liner 6,
The pressure surfaces of the seal rings 1 and 2 are arranged on the seawater side, and the pressure surfaces of 3 and 4 are arranged on the stern tube 8 side to form annular chambers. Reference numeral 7 is an annular chamber between the seal rings 3 and 4, and 9 is a stern tube bearing fixed in the stern tube 8. Reference numerals 11 and 12 denote a pressure tank for the annular chamber and a gravity tank for the stern tube, which are sources of pressure supply in the ship, and pressure supply pipelines 14 communicating with the annular chamber 7 between the seal rings 3 to 4 and the stern tube bearing 9 from the respective tank bottoms. Predetermined pressure oil is supplied to the annular chamber 7 and the stern tube bearing 9 by 15. The pressure tank 11 is installed so that the oil surface is higher than the oil surface of the gravity tank 12 by about 1 m, and the oil surface height of the gravity tank 12 may be the same as the conventional one. Lubricating oil in the stern pipe 8 is returned to the sump tank 13 by the return pipe 16 via the valve 23. A pipe 18 is connected from the sump tank 13 via a pump 19 to the upper part of the annular chamber pressure tank 11.
An oil overflow pipe (20) is connected to the top plate of the gravity tank (12) near the oil surface of the annular chamber pressure tank (11), and a pipe line (17) is connected to the sump tank (13) near the oil surface of the gravity tank (12). Pipeline 14,15,16
Stop valves 21, 22, and 23 are arranged at appropriate positions. Alternatively, the pressure supply line 14 can be communicated with the annular chamber 7'constituted by the seal rings 2 and 3 as shown by the dotted line in FIG. FIG. 2 shows another embodiment of the present invention, in which the pressure chamber 11 for the annular chamber shown in FIG. 1 is eliminated and instead the pressure supply pipe communicating from the lower part of the gravity tank 12 to the stern pipe bearing 9 is connected. The branch pipe 14 is taken from an appropriate position of the passage 15 and communicated with the annular chamber 7 via the flow control type pressure control device 25.

(Advantageous Effects) According to the stern tube sealing device according to the present invention described above, the pressure oil supplied from the annular chamber pressure tank 11 to the annular chamber 7 via the pressure supply pipe line 14 is always higher than the stern tube bearing hydraulic pressure. Since the difference in oil level between the pressure tank and the gravity tank is large, the oil acts on the back surface of the seal ring 4 to lift the lip and flow into the stern tube 8. The inflowing oil returns to the sump tank 13 via the return line 16. The increased oil in the sump tank 13 is returned by the pump 19 to the pressure tank 11 through the line 18. When the amount of oil in the tank 11 increases, it flows into the stern tube gravity tank 12 through the oil overflow pipe 20. The increased oil in the gravity tank 12 flows into the sump tank 13 through the line 17, and is returned to the annular chamber pressure tank 11 by the pump 19.

In the unlikely event that the seal ring 3 is damaged and oil leaks out of the ship, the oil level in the pressure tank 11 will suddenly decrease and an alarm will be issued, so when the stop valve 21 is closed, it will be saved as a spare until then. The seal ring 4 that has been used is brought into an operating state, the lubricating oil in the stern tube 8 is sealed, and leakage from the outboard is prevented. In the case of the device shown in FIG. 2 in which the pressure tank for the annular chamber is abolished, the change in the hydraulic pressure in the stern tube is instantaneously detected by the action of the constant flow control type pressure control device, and the oil amount is changed to return to a constant differential pressure. The pressurized oil having a constant differential pressure can always be supplied to the annular chamber. Further, according to the stern tube device according to the present invention, (1) since the lubricating oil is always forced to be fed into the annular chamber between the seal rings 3 and 4, the cooling effect of the seal ring is large and the life of the seal ring is extended.

(2) Since the seal ring 4 is always floating above the shaft, it is not in contact with the shaft, and the seal ring is not worn as much as the propeller shaft liner.

(3) Since the annular chamber between the seal rings 3 and 4 always maintains a higher pressure than the stern tube bearing hydraulic pressure, the seal rings 1, 2
Even if seawater intrudes due to damage to the stern tube, it will not penetrate into the stern tube bearing.

As explained above, the sealing performance is significantly improved and pollution,
It will greatly contribute to maintenance.

Although the present invention has described a stern tube sealing device in which two seal rings facing the seawater side and two seal rings facing the stern tube side are arranged, a conventional seawater side two stern tube side one sealing ring It can also be applied to a stern tube sealing device in which the above are arranged.

BRIEF DESCRIPTION OF THE DRAWINGS The drawings show an embodiment of the present invention. FIG. 1 is a longitudinal sectional view of the structure of a stern tube sealing device according to the present invention and a system diagram showing a lubricating oil feeding mechanism. FIG. 2 is a longitudinal sectional view of an apparatus according to another embodiment and a system diagram showing a lubricating oil feeding mechanism. (1), (2), (3), (4) …… Seal ring (5) …… Housing member, (6) …… Propeller shaft liner (8) …… Stern tube, (9) …… Stern tube Bearing (10) …… Stern tube seal, (11) …… Annular chamber pressure tank (12) …… Stern tube gravity tank (13) …… Sump tank (14) …… Seal pressure supply pipe (15)… … Pressure supply pipe for stern pipe (16) …… Return pipe (17), (20) …… Oil overflow pipe (19) …… Pump (18) …… Oil supply pipe

Claims (2)

[Scope of utility model registration request] 1. A plurality of seal rings which are constituted by a plurality of seal rings slidably contacting a propeller shaft liner and a housing member which holds the seal rings and is fixed to a hull stern member and surrounds the propeller shaft. In a stern tube sealing device in which a plurality of seal rings that direct pressure surfaces toward the stern tube bearing side are arranged, a stern tube gravity tank and two seal rings closest to the stern tube bearing side at a higher position A stern tube seal, characterized in that a pressure tank for an annular chamber configured is installed, a pressure oil supply pipe is made to communicate, and the respective tanks are connected so as to circulate the annular chamber pressure higher than the stern tube internal pressure. apparatus. 2. The stern tube sealing device according to claim 1, wherein the oil overflow pipe of the pressure chamber for the annular chamber is connected to the top plate of the stern pipe pressure tank.