A compressed air control type sealing actuator for a ship stern seal

Abstract

The application relates to a compressed air control type sealing execution mechanism of a ship stern sealing device, which comprises a sealing bush and a sealing seat body, the sealing bush is a dynamic ring, is connected with a propeller and rotates with a propeller shaft; the sealing seat body is a static ring, is installed in a propeller shell, and a wear-resistant ring and four lip type seals are arranged between the sealing seat body and the sealing bush, five cavities are formed, the lip type seal holding force is adjustable, the holding forces of the two lip type seals facing seawater are different, the holding force on the outside is smaller than that on the inside, and the pressure loss generated when compressed air passes through the inside seal can be compensated. When the water depth changes or the environmental pressure changes greatly, the lip type seal inner-outer pressure difference changes rapidly, the lip type seal opening does not become large due to the sudden increase of the pressure difference to cause seawater leakage, and the lip type seal does not become small due to the sudden decrease of the pressure difference to cause the lip type seal abrasion, and the working reliability and service life of the stern sealing device are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to a compressed air control type ship stern sealing device, in particular to a sealing actuator. BACKGROUND

[0002] At present, the sealing performance of the ship stern sealing device is very mature, and the sealing forms mainly include labyrinth seal, rotary dynamic seal, packing seal, mechanical seal and the like. The working principle is generally to form a suction effect through a friction pair to achieve sealing effect, or to form a dynamic pressure water film through a friction pair to achieve sealing effect, or to achieve sealing effect through throttling effect. The ship designer only needs to select a suitable sealing form according to the technical parameters such as the diameter of the propeller shaft, the speed, the use depth, the leakage requirement and the fund requirement of the target ship. However, with the promulgation of the requirement of the International Marine Environment Organization on the offshore discharge of ships, the traditional stern sealing device is difficult to meet the requirement, and must be improved and upgraded. Foreign advanced sealing manufacturers have developed and popularized a new type of stern sealing device, i.e. air stern sealing device. The working principle of the air stern sealing device is to set two lip seals facing seawater and lip seals facing lubricating oil, and to pass compressed air with controllable pressure in the middle, so that the compressed air pressure is slightly greater or slightly less than the seawater pressure. In this way, the lip seal is either just lifted to let the air overflow to prevent seawater from entering, or is just closed to separate seawater. At the same time, an air outlet is arranged in the air chamber, and once seawater enters or lubricating oil leaks, it will be brought to the recovery bottle by the air flow, realizing zero discharge of the pollution source.

[0003] The air stern sealing device has the advantages of realizing zero discharge, reducing the friction between the lip seal and the rotating shaft, reducing wear and prolonging the service life. The difficulty lies in how to realize precise supply of compressed air pressure and flow, so that the lip seal is lifted as required and the opening is ensured to be stable. Especially for working conditions such as semi-submersible ships and offshore platforms, where the water depth changes greatly, when the draft or seawater impact is large, whether the sealing actuator can have a good impact protection design and sensitive lifting or closing action is very important. Therefore, it is necessary to innovatively design the limiting ability and sensitivity adjustment ability of the sealing actuator. SUMMARY

[0004] The purpose of the present application is to provide a compressed air control type ship stern sealing device sealing actuator, which is a sealing structure with impact protection and sensitivity adjustment, used to solve the problem of delayed opening response of the lip seal caused by the increase of the water depth change or the large pressure impact of the air stern sealing device, thereby improving the working reliability of the air stern sealing device.

[0005] To achieve the above object, the technical scheme of the present application is: a compressed air control type ship stern sealing device sealing actuator, comprising a sealing bushing and a sealing seat body, the sealing bushing is a dynamic ring, connected with a propeller and rotates with the propeller shaft; the sealing seat body is a static ring, installed in the propeller shell, a wear-resistant ring and four lip seals are arranged between the sealing seat body and the sealing bushing, forming five cavities, the lip seal holding force is adjustable, the holding force of the two lip seals facing seawater is different, the outside holding force is smaller than the inside, which can compensate for the pressure loss when the compressed air passes through the inside seal.

[0006] Further, the sealing bushing is made of stainless steel, and the outer surface is plated with ceramic.

[0007] Further, the sealing seat body is provided with a compressed air channel and a lubricating oil channel; the compressed air passes through the compressed air channel to the cavity formed by the sealing ring to supply the lip seal facing the seawater side; the lubricating oil passes through the lubricating oil channel to the cavity formed by the sealing ring to supply the lip seal facing the propeller bearing side.

[0008] Further, the sealing seat body is provided with a limiting ring, and the two lip seals facing the seawater side are both provided with a limiting ring for limiting the opening size of the lip seal when the pressure difference suddenly changes.

[0009] Further, the sealing seat body is provided with a limiting ring, and the two lip seals facing the seawater side are both provided with a limiting ring for limiting the opening size of the lip seal when the pressure difference suddenly changes.

[0010] Further, the two lip seals facing the seawater side are provided with adjusting springs for adjusting the holding force of the lip seal through the adjusting springs, and the opening holding force is matched with the compressed air pressure; at the same time, when the pressure difference P0-P2 suddenly decreases, that is, when the seawater pressure suddenly increases, the two lip seals hold the rotating sealing bushing, and the holding force will not cause excessive wear between the lip seal and the sealing bushing.

[0011] The beneficial effects of the present application are:

[0012] The compressed air control type ship stern sealing device sealing actuator of the present application can quickly change the pressure difference inside and outside the lip seal when the water depth changes or the environmental pressure changes, at this time, the lip seal opening will not be enlarged due to the sudden increase of the pressure difference to cause seawater leakage, and will not be reduced due to the sudden decrease of the pressure difference to cause lip seal wear, thereby improving the working reliability and service life of the stern sealing device. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 is a schematic diagram of the compressed air control type ship stern sealing device sealing actuator of the present application;

[0014] Figure 2 This is a partially enlarged view of the sealing actuator of the compressed air controlled marine stern sealing device of the present invention. Detailed Implementation

[0015] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0016] like Figure 1 As shown in Figure 2, a compressed air controlled type ship stern sealing device sealing actuator of the present invention includes a sealing bushing 1 and a sealing seat 2.

[0017] The sealing bushing 1 is a rotating ring, made of stainless steel and ceramic-plated, which is connected to the propeller through mounting surface A and rotates with the propeller shaft; the sealing seat 2 is a stationary ring, which is installed on the propeller housing through mounting surface B, and includes a wear-resistant ring 21, a first lip seal 22, a second lip seal 23, a third lip seal 24, a fourth lip seal 25, a first limiting ring 26, a second limiting ring 27, a connecting flange, a sealing seat, a compressed air passage 28, a lubricating oil passage 29, etc.

[0018] The sealing seat body 2 is equipped with a wear-resistant ring 21 and four lip seals. The first lip seal 22 and the second lip seal 23 are installed facing the seawater for double protection; the third lip seal 24 and the fourth lip seal 25 are installed facing the lubricating oil for double protection; a total of 5 cavities are formed, namely cavity 1a, cavity 2b, cavity 0c, cavity 3d and cavity 4e; the clamping force of the lip seals can be adjusted. The clamping force of the first lip seal 22 and the second lip seal 23 are different. The clamping force of the first lip seal 22 is slightly less than that of the second lip seal 23 to compensate for the pressure loss when compressed air passes through the clamping force of the second lip seal 23, ensuring that when the lip of the second lip seal 23 is raised, the first lip seal 22 is raised accordingly.

[0019] The cavities 1a, 2b, 0c, 3d and 4e in the sealing seat 2 are respectively connected to seawater, compressed air, compressed air, lubricating oil and lubricating oil, with pressures of P1, P2, P0, P3 and P4 respectively, and P1 < P2 < P0 < P3 > P4.

[0020] The sealing seat 2 is provided with a compressed air passage 28 and a lubricating oil passage 29; compressed air is supplied to the first and second lip seals 22 and 23 facing the seawater through the cavity 0 formed by the sealing ring; lubricating oil is supplied to the third and fourth lip seals 24 and 25 facing the propeller bearing through the cavity 0 formed by the sealing ring.

[0021] The first and second limiting rings 26 and 27 are arranged in the sealing seat 2, and the first and second lip seals 22 and 23 facing the seawater side are provided with the limiting rings. When the pressure difference P0-P2 suddenly increases, i.e. the seawater pressure suddenly decreases, the lips of the first and second lip seals 22 and 23 will suddenly increase, which easily causes the seawater to leak. Therefore, the limiting rings can limit the opening size of the lip seals when the pressure difference suddenly changes.

[0022] The first and second lip seals 22 and 23 can be adjusted by springs, and the opening and clamping forces of the first and second lip seals 22 and 23 are matched with the compressed air pressure. Meanwhile, when the pressure difference P0-P2 suddenly decreases, i.e. the seawater pressure suddenly increases, the lip seals will clamp the rotating bushing, and the clamping force will not cause excessive wear between the lip seals and the bushing.

Claims

1. A compressed air controlled type ship stern seal device sealing actuator, characterized in that: The sealing bushing is a dynamic ring connected with the propeller and rotates with the propeller shaft; the sealing seat body is a static ring installed in the propeller shell, and a wear-resistant ring and four lip seals are arranged between the sealing seat body and the sealing bushing to form five cavities, the lip seal holding force is adjustable, the holding force of the two lip seals facing seawater is different, the outside holding force is smaller than the inside, which can compensate for the pressure loss when compressed air passes through the inside seal; the sealing seat body is provided with a limiting ring, and the two lip seals facing seawater are provided with limiting rings to limit the opening size of the lip seal when the pressure difference changes suddenly; the sealing seat body and the four lip seals form cavities 1, 2, 0, 3 and 4, and the cavities 1, 2, 0, 3 and 4 in the sealing seat body are respectively communicated with seawater, compressed air, compressed air, lubricating oil and lubricating oil.

2. The compressed air controlled ship stern seal sealing actuator according to claim 1, characterized in that: The sealing bushing is made of stainless steel, and the outer surface is plated with ceramic.

3. The compressed air controlled ship stern seal sealing actuator according to claim 1, characterized in that: The sealing seat body is provided with a compressed air channel and a lubricating oil channel; the compressed air passes through the compressed air channel to the cavity formed by the sealing ring to supply the lip seal facing seawater; the lubricating oil passes through the lubricating oil channel to the cavity formed by the sealing ring to supply the lip seal facing the propeller bearing side.

4. The compressed air controlled ship stern seal sealing actuator of claim 1, wherein: The pressures in the cavities 1, 2, 0, 3 and 4 are P1, P2, P0, P3 and P4 respectively, and P1 5. The compressed air controlled ship stern seal sealing actuator according to claim 4, characterized in that: The two lip seals facing seawater are provided with adjusting springs for adjusting the holding force of the lip seals through the adjusting springs, and the opening holding force is matched with the compressed air pressure; at the same time, when the pressure difference P0-P2 suddenly decreases, that is, when the seawater pressure suddenly increases, the two lip seals hold the rotating sealing bushing, and the holding force will not cause excessive wear between the lip seal and the sealing bushing.

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