JPH079760Y2 - Stern tube shaft sealing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an improvement of a stern tube shaft sealing device that seals a propeller shaft of a ship with a plurality of lip seals.

[Conventional technology]

Conventionally, as a kind of stern tube shaft sealing device, for example,
There is one disclosed in Japanese Patent No. 59-145499.

This stern tube shaft sealing device will be described in brief. The seawater lip seal closest to the stern on the inner periphery of the casing, and two lips located inside the ship and facing the seawater lip seal. Of the two annular chambers formed between these three lip seals, the chamber on the stern side is used as a pressure chamber to which pressurized gas having a pressure appropriately higher than seawater pressure is supplied. The pressurized gas supplied to the seawater overflows into the seawater outside the ship from the seawater lip seal to prevent the seawater from entering.

Of the two chambers, a recovery hole is provided in a chamber on the inner side of the ship, and the pressurized gas flowing from the pressure chamber to the inner side of the ship through the intermediate lip seal and the bearing oil closest to the inner space of the ship. The stern tube bearing oil onboard the ship that leaks from the oil lip seal is collected.

[Problems to be solved by the device]

However, according to the conventional stern tube shaft sealing device,
Since the middle lip seal of the book lip seal is in a dry state, deterioration due to premature wear or abnormal heat generation easily occurs, and in this case, the amount of pressurized gas passing through the middle lip seal increases, so There is a problem that the lip seal is prevented from overflowing, and as a result, the sealing property and life of the lip seal for seawater are shortened. Further, since the chamber on the inside of the ship is at atmospheric pressure, the differential pressure acting as a tightening load on the lip seal for bearing oil, which is closest to the inside of the ship, is large, and therefore the lip seal for bearing oil is also likely to be worn early.

In view of such a point, the present invention has an object to provide a stern tube shaft sealing device excellent in sealing property and durability.

[Means for Solving the Problems]

In order to solve the above problems, the present invention provides a seawater lip seal closest to the stern on the inner circumference of a casing surrounding a propeller shaft, and two seawater lip seals located inside the ship and facing the seawater lip seal. In the stern tube shaft sealing device, which comprises a pressure chamber to which a pressurized gas having a pressure appropriately higher than seawater pressure is provided between the seawater lip seal and the intermediate lip seal. Next to the inner side of the pressure chamber, the oil seal is partitioned by the middle lip seal and the lip seal closest to the inside of the ship, and an oil chamber with an air vent line in the upper part and a drain line in the lower part is provided. Is filled with oil from an oil tank located at a higher position through a hydraulic line, and the pressure in the oil chamber is lower than the pressure chamber and the bearing oil chamber on the inner side of the lip seal closest to the inside of the ship and less than atmospheric pressure. Also And wherein the set to pressure.

[Action]

The oil chamber provided adjacent to the inside of the pressure chamber is filled with oil from the oil tank whose liquid level is higher than that of the oil chamber. The middle lip seal that separates the spaces is oil-lubricated. Since the oil tank applies a pressure lower than the pressure chamber and the bearing oil chamber and higher than the atmospheric pressure to the oil chamber, the differential pressure acting as a tightening load on the lip seal closest to the ship is small. Becomes

The pressurized gas with a pressure higher than the seawater pressure and oil chamber pressure supplied to the pressure chamber prevents seawater from entering by overflowing from the seawater lip seal to seawater, while the intermediate lip seal causes the oil chamber The oil in the oil chamber is prevented from flowing out to the stern side by spilling over to the stern side, and as a bubble in the oil chamber floats up and is released into the outside air from the upper air vent line. The bearing oil or seawater that leaks into the oil chamber should be recovered from the drain line.

〔Example〕

Hereinafter, the present invention will be described with reference to an embodiment shown in FIGS.

Reference numeral 1 is a ship body, 2 is a propeller shaft inserted through the ship body 1 through a stern tube bearing 3 shown in FIG. 2, and 4 is a propeller shaft 2.
It is a sleeve that is installed on.

The stern tube shaft sealing device of the present embodiment is provided with a lip seal 6 made of an elastic body on the inner circumference of a casing 5 located on the stern side of the stern tube bearing 3 and fixed to the ship body 1 and surrounding the propeller shaft 2.
It has a structure in which 7, 8 are held, and the lip seal 6 for seawater, which is closest to the stern, faces the stern side, and the other lip seals 7, 8 face the inside of the ship.

Between the lip seal 6 for seawater and the intermediate lip seal 7, a pressure chamber 9 to which compressed air as pressurized gas is supplied from a compressed air supply source 12 of an engine room (not shown) through an air supply line 16 is formed. Further, between the intermediate lip seal 7 and the anti-bearing oil lip seal 8 closest to the inside of the ship, an air vent line 17 is opened in the upper part, a drain line 18 is formed in the lower part, and a hydraulic line 19 extending from the oil tank 20 is opened in the oil. Room 10 is provided.

The compressed air supplied from the compressed air supply source 12 to the pressure chamber 9 passes through the filter 13 and the flow meter 14, and is controlled by the differential pressure adjusting valve 15 which is controlled based on the seawater pressure detected by the seawater pressure detecting means (not shown). , Always 0.1kgf / cm ² above seawater pressure
The high pressure is maintained.

Further, an oil tank that communicates with the oil chamber 10 via the hydraulic line 19
The liquid level of the oil in 20 is higher than the oil chamber 10 and the bearing oil tank 21 for supplying the bearing oil to the stern tube bearing 3
Since the oil chamber 10 is located at a lower position than that, the entire circumference of the oil chamber 10 is filled with oil, and the pressure p ₁ thereof is the air pressure in the pressure chamber 9 and the bearing oil chamber on the inboard side of the lip seal 8 for bearing oil.
It is set to 0.3 kgf / cm ² or more lower than the bearing oil pressure p _{0 of} 11. Reference numeral 22 is a drain tank, and by opening a valve 23 provided in the drain line 18, the bearing oil leaked from the bearing oil chamber 11 into the oil chamber 10 and the oil leaking into the oil chamber 10 through the lip seals 6 and 7. Collected seawater A.

In the present embodiment having the above-described configuration, the compressed air supplied to the pressure chamber 9 is higher than the pressure of the seawater A, so that the inside of the seawater A flows from the gap between the sliding seal 6 for seawater and the sleeve 4. To prevent seawater A from entering the ship. On the other hand, the compressed air overflows from the middle lip seal 7 facing the sea water lip seal 6 to the oil chamber 10 having a lower pressure than the pressure chamber 9, and the oil filled in the oil chamber 10 is pressurized. Completely prevent it from passing through the chamber 9 into the seawater A. Then, the compressed air overflowing into the oil chamber 10 floats in the oil as bubbles B, and the air vent line opened at the upper part.
Released from 17 into the atmosphere.

Since the entire circumference of the oil chamber 10 is filled with the oil from the oil tank 20, the intermediate lip seal 7 that separates the oil chamber 10 from the pressure chamber 9 is always oil lubricated, and the oil chamber Than 10
Since the air pressure in the pressure chamber 9, which is a high pressure of about 0.3 kgf / cm ² , acts in the opposite direction to the load of the lip seal 7 on the sleeve 4, wear and heat generation are suppressed and the life thereof is significantly improved. In addition, since the pressure p ₁ is applied to the oil chamber 10 by the oil tank 20, the lip seal 8 for bearings has the sleeve 4
Differential pressure from the bearing oil chamber 11 side acting as a tightening load on the bearing
Since p ₀ -p ₁ is always maintained at about 0.3 kgf / cm ² , the life of the lip seal 8 is significantly improved.

In the above embodiment, the pressure chamber 9 is automatically adjusted to a pressure higher than the pressure of the seawater A by the differential pressure adjusting valve 15 controlled by the seawater pressure detecting means. A regulator, for example, is used instead of the adjusting valve 15 to set a constant high pressure value that is always 0.1 kgf / cm ² or more higher than the pressure of the seawater A that fluctuates according to the water depth of the ship. May be.

[Effect of device]

As described above, according to the present invention, the intermediate lip seal, which was conventionally dry sliding, is lubricated by the oil in the oil chamber, and due to the pressure applied to the oil chamber, the lip seal for bearing oil closest to the ship Since the load on the lip seal is reduced, the service life of these lip seals is significantly improved. Moreover, since the oil chamber is at a lower pressure than the pressure chamber and the bearing oil chamber, the outflow of bearing oil to the outboard can be completely prevented. It has an excellent effect.

[Brief description of drawings]

FIG. 1 is a sectional view showing one embodiment of the stern tube shaft sealing device of the present invention, FIG. 2 is the same piping system diagram, and FIG. 3 is FIG. 1 III-II.
It is a fragmentary sectional view in Ship I. 2 ... Propeller shaft, 3 ... Stern tube bearing 5 ... Casing, 6 ... Lip seal for sea water 7 ... Intermediate lip seal 8 ... Lip seal for bearing oil 9 ... Pressure chamber, 10 ... Oil chamber, 11 …… Bearing oil chamber 12 …… Compressed air supply source 17 …… Air vent line, 18 …… Drain line 19 …… Hydraulic line, 20 …… Oil tank, A …… Seawater

Claims (1)

[Scope of utility model registration request] 1. An inner periphery of a casing surrounding a propeller shaft is provided with a lip seal for seawater closest to the stern, and two lip seals located inside the ship and facing the lip seal for seawater. In the stern tube shaft sealing device, between the lip seal for seawater and the intermediate lip seal, a pressure chamber provided with a pressurized gas having an appropriately higher pressure than seawater pressure is provided,
Next to the inside of the pressure chamber on the inside of the ship, an oil chamber having an air vent line in the upper part and a drain line in the lower part, which is partitioned by the middle lip seal and the lip seal closest to the inside of the ship, is provided, and the liquid level is the oil chamber. The oil from the oil tank located at a higher position than that is filled with oil through the hydraulic line, and the pressure in the oil chamber is lower than the pressure chamber and the bearing oil chamber on the inner side of the lip seal closest to the inside of the ship and at the atmospheric pressure. A stern tube shaft sealing device characterized by being set to a higher pressure than that.