JPH0645438Y2 - Stern tube shaft sealing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a shaft sealing technique, and relates to a stern tube shaft sealing device for sealing a stern propeller shaft of a ship.

[Conventional technology]

Conventionally, as a stern tube shaft sealing device of this type, as illustrated in FIG. 2, a propeller shaft (3) having a propeller boss (2) mounted on the stern side of a hull (1) is provided on the shaft (3). A sleeve seal (5) (6) on the seawater side and the inside of the ship, which is in sliding contact with the outer peripheral surface of the sleeve liner (4) exteriorly mounted on the ship, and a segment seal (7) located between the lip seals (5) and (6).
It is known that the shaft is sealed with a seal structure including (8). High pressure air is pressure-fed from a compressed air supply unit (not shown) to a mounting space of the segment seals (7) and (8) through a pressure guide path (9), and the air causes the segment seal (7) and the lip seal (5) to be delivered. It is designed to prevent leakage of seawater (S) into the ship and leakage of inboard bearing oil (O) into the seawater (S) by being discharged through the seawater (S).

[Problems to be solved by the invention]

However, according to the above configuration, the seawater side lip seal (5)
When the segment seals (7) and (8) are not supplied with air, seawater (S) will enter when the segment seals (7) and (8) are installed. Even when it is stopped, it is necessary to continuously supply air to the mounting space, which has a drawback of increasing energy consumption.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention solves the above problems by providing a lip seal facing the seawater side, a hollow inflatable seal which is provided on the seawater side of the lip seal, and which is in close contact with the shaft circumference by the introduction of compressed air. A first pressure guide passage extending from an air supply portion and supplying compressed air to counter the seawater pressure to the back surface of the lip seal, and a second pressure guide passage supplying compressed air to the hollow portion of the inflatable seal. A solenoid valve disposed in the first pressure guiding path, a solenoid valve disposed in the second pressure guiding path, and a branch of the solenoid valve of the second pressure guiding path from the inflatable seal side. The exhaust control solenoid valve for opening and closing the exhaust passage, the solenoid valve for the first pressure guide passage and the exhaust control solenoid valve for the exhaust passage when the shaft rotation signal is given, and the solenoid for the second pressure guide passage are opened. Valve shuts off and axis stop signal Provided is a stern tube shaft sealing device including a control unit that opens a solenoid valve of a second pressure guiding path and closes a solenoid valve of the first pressure guiding path and an exhaust control electromagnetic valve of an exhaust path when given To do.

[Action]

According to the present invention, when the propeller shaft rotates, the inflatable seal is in a non-contact state with the shaft circumference of the propeller shaft by being exhausted and contracted, and the compressed air from the compressed air supply unit passes through the first pressure guiding path. Since it is supplied to the rear surface of the lip seal, that is, the side opposite to the seawater, the compressed air is discharged into the seawater for sealing. Also, when the propeller shaft is stopped, the supply of compressed air to the back surface of the lip seal is cut off, and this compressed air is introduced into the hollow part of the inflatable seal via the second pressure guiding path, and the exhaust path is blocked. As a result, the inflatable seal swells and comes into close contact with the circumference of the propeller shaft to prevent the entry of seawater.

[Embodiment] The embodiment shown in FIG. 1 is one in which the present invention is applied to the stern tube shaft sealing device of the type shown in FIG.
That is, the inflatable seal (11) made of a rubber material is attached to the inner circumference of the casing (10) protruding further outward from the seawater side lip seal (5). A first pressure guide passage (9) and a second pressure guide passage extending from the compressed air supply portion (14) are provided in the space where the segment seals (7) and (8) are mounted and the hollow portion (12) of the inflatable seal (11). (13) are connected to each other, of which the first pressure guiding path (9)
Filter (15), flow meter (16), regulator (1
7), a solenoid valve (18), a pressure gauge (19), etc. are provided, and a regulator (2
0), a solenoid valve (21), and a pressure gauge (23) are provided, and an exhaust passage branched from the inflatable seal (11) side of the solenoid valve (21) in the second pressure guide passage (13). An exhaust control solenoid valve (22) is arranged in the.

The solenoid valves (18) (21) (22) are
The open / close valve operation is controlled by an electric signal from the control section (24) to the (s) (21s) (22s). To explain this in more detail, the solenoid valve (18) is normally operated (when the ship is navigating).
And (22) are open and the solenoid valve (21) is closed, and the air set to a predetermined pressure by the regulator (17) passes through the solenoid valve (18) and the segment seal (7).
(8) It is designed to be supplied to the installation space, and this air is discharged from the back surface of the lip seal (5) on the seawater side through the inner circumference into the seawater (S) to provide a shaft sealing function. Played. On the other hand, the inflatable seal (11) contracts and is not in contact with the sleeve liner (4). Here, when the propeller shaft (3) is stopped, the electric signal from the control section (24) is switched to open the solenoid valve (21),
The solenoid valves (18) and (22) are closed, that is, the inflatable seal (11) is supplied with compressed air and expands to perform a shaft-sealing function, and at the same time, to the space where the segment seals (7) and (8) are mounted. The supply of compressed air is stopped.

The control unit (24) uses a shaft rotation signal (pulse signal) and a shaft stop signal (constant voltage signal) input from a rotary encoder or another sensor provided in the propeller shaft (3) or the engine control unit, The above operation is automatically controlled.

[Effect of device]

As described above, the stern tube shaft sealing device according to the present invention is
While the propeller shaft is rotating, the inflatable seal is kept out of contact with the circumference of the propeller shaft, while compressed air from the compressed air supply unit is supplied to the back surface of the lip seal and discharged into seawater to seal the propeller shaft. When the axis is stopped,
Since the control system is configured to stop the supply of compressed air to the back of the lip seal and to completely shut off the seawater by operating the inflatable seal, it is necessary to reliably seal the seawater and inboard oil when the ship is stopped. In particular, since it is not necessary to continuously release the compressed air from the lip seal into the seawater even during loading and unloading or for a long period of berthing, the energy consumption can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic system explanatory view showing an embodiment of the present invention, and FIG. 2 is a half sectional view showing an example of a conventional structure. (1) …… Hull, (2) …… Propeller boss (3) …… Propeller shaft, (4) …… Sleeve liner (5) (5a) (5b) (6) …… Lip seal (7) (8) ) …… Segment seal, (9) First pressure guide path, (13) Second pressure guide path (11) …… Inflatable seal, (12) …… Hollow part (14) …… Compressed air supply part, (18) (21) (22) …… Solenoid valve (24) …… Control unit

Claims (1)

[Scope of utility model registration request] 1. A stern tube shaft sealing device for sealing the shaft circumference of a stern propeller shaft, wherein a lip seal facing the seawater side and a seal seal provided on the seawater side of the lip seal and brought into close contact with the shaft circumference by the introduction of compressed air. A hollow inflatable seal for supplying compressed air to the back of the lip seal for supplying compressed air to counter seawater pressure and supplying compressed air to the hollow part of the inflatable seal A second pressure guiding path, a solenoid valve arranged in the first pressure guiding path, a solenoid valve arranged in the second pressure guiding path, and an electromagnetic valve in the second pressure guiding path. An exhaust control solenoid valve that opens and closes an exhaust passage branched from the inflatable seal side of the valve; and a solenoid valve of the first pressure guiding passage and an exhaust control solenoid valve of the exhaust passage when a shaft rotation signal is given. Second impulse Control unit for closing the solenoid valve of the first pressure guiding passage and the exhaust control solenoid valve of the exhaust passage while opening the solenoid valve of the second pressure guiding passage when the solenoid valve of the passage is closed and the axis stop signal is given. And a stern tube shaft sealing device.