Watertight sewage tank structure of cargo hold of LNG transport ship

Abstract

The utility model relates to the field of shipbuilding, and provides a watertight sewage tank structure of a cargo hold of an LNG (Liquefied Natural Gas) transport ship. Comprising a cabin body, the upper portion of the cabin body is provided with a well mouth, the outer side of the well mouth is provided with a circle of well edge, the top of the well edge is provided with a well lid, the top of the well edge is provided with a flange ring, the well lid is provided with a circle of bolt holes corresponding to bolt holes in the flange ring, the top face of the well lid is provided with four installation holes, and liquid level sensors are installed in the installation holes respectively. Wherein two liquid level sensors extend into the low liquid level in the cabin body, and the other two liquid level sensors extend into the high liquid level in the cabin body. The watertight well lid is adopted, the well lid, the well edge and the well mouth are connected in a sealed mode, sewage can be effectively prevented from overflowing from the top when the liquid level sensor loses efficacy, and a cabin of a ship is prevented from being polluted by the sewage. The liquid level sensor is installed on the well lid in a flange installation mode, disassembly, replacement and maintenance at any time are convenient, and the internal space of the sewage tank is not occupied.

Description

Technical Field

[0001] The utility model relates to the field of ship construction, in particular to a watertight sewage tank structure of a cargo hold of an LNG transport ship. Background Art

[0002] According to the International Pollution Prevention Convention, sewage generated during ship operation cannot be discharged into the sea at will. Domestic sewage needs to be stored in a separate sewage tank before being discharged to the shore or to the high seas. A wellhead is generally set on the top of the sewage tank, and a sewage manhole cover is installed on the wellhead to prevent people from accidentally falling in.

[0003] Liquid level sensors are installed in the sewage tanks of conventional cargo holds, which can send out alarm signals and notify discharge treatment when the liquid level in the sewage tank exceeds the control range. Some sewage manhole covers are usually equipped with grille holes to achieve ventilation in the sewage tank and to facilitate the overflow of sewage inside when the liquid level exceeds the limit. For LNG carriers, the space in the sewage tank is limited, which makes it inconvenient to install liquid level sensors, and when the liquid level sensor installed in the sewage tank fails, it cannot be repaired or replaced in time. In addition, LNG carriers have watertight requirements for sewage tanks, and it is necessary to avoid pollution in the cabin due to sewage overflow. Summary of the invention

[0004] In order to meet the watertightness requirements of the sewage tank of an LNG carrier and facilitate the replacement and maintenance of a liquid level sensor, the utility model provides a watertight sewage tank structure of a cargo hold of an LNG carrier.

[0005] The technical solution adopted by the utility model is:

[0006] A watertight sewage tank structure for the cargo hold of an LNG carrier comprises a cabin, a wellhead is provided on the upper part of the cabin, a well edge is provided on the outer side of the wellhead, the well edge is a cylindrical structure, the bottom of the well edge is fixedly welded to the top surface of the cabin top deck, the welding point between the well edge and the deck deviates from the edge of the wellhead, a manhole cover is installed on the top of the well edge, a flange ring is installed on the top of the well edge, a circle of bolt holes is provided on the flange ring, a circle of bolt holes corresponding to the bolt holes on the flange ring is provided on the manhole cover, the manhole cover and the well edge are fixedly connected by a plurality of bolts, a sealing ring is installed between the bottom surface of the manhole cover and the flange ring of the well edge; four mounting holes are provided on the top surface of the manhole cover, liquid level sensors are respectively installed in the mounting holes, two of which extend into low liquid levels in the cabin, and the other two extend to high liquid levels in the cabin, and the liquid level sensors are sealed and installed between the corresponding mounting holes.

[0007] Furthermore, vertical sleeves are respectively installed in the mounting holes, the outer diameter of the sleeves corresponds to the inner diameter of the mounting holes, the sleeves are welded to the manhole cover, and the two ends of the sleeves extend out of the upper and lower sides of the manhole cover respectively; a mounting tube is coaxially inserted in the sleeve, the outer wall of the mounting tube is covered with a rubber sleeve, the rubber sleeve of the mounting tube is squeezed and fit with the inside of the sleeve, the upper end face of the mounting tube is provided with a mounting flange, and the liquid level sensor is fixedly connected to the mounting flange.

[0008] Furthermore, the bottom surface of the liquid level sensor seals the upper opening of the sleeve, and a sealing ring is installed between the bottom of the liquid level sensor and the mounting flange.

[0009] Furthermore, the bolt holes on the flange ring are located outside the well edge.

[0010] Furthermore, a pair of U-shaped pull rings are welded to the top surface of the manhole cover, and the U-shaped pull rings are distributed on both sides of the liquid level sensor.

[0011] Furthermore, the surfaces of the well edge, well cover, casing, installation pipe and U-shaped pull ring are all provided with zinc coating.

[0012] Furthermore, ventilation ducts connected to the main deck are provided on both sides of the cabin top.

[0013] After adopting the above technical scheme, the beneficial effects of the utility model are:

[0014] The use of a watertight manhole cover, which forms a sealed connection between the manhole cover, the well edge and the wellhead, can effectively prevent sewage from overflowing from the top when the liquid level sensor fails, and prevent sewage from polluting the ship's cabin. The liquid level sensor is installed by installing a casing and a mounting pipe on the manhole cover, and a seal is formed between the casing, the mounting pipe and the liquid level sensor, which can prevent sewage from overflowing; the liquid level sensor is installed on the manhole cover by flange installation, which is convenient for disassembly, replacement and maintenance at any time, and does not occupy the space inside the sewage tank. Using four liquid level sensors to monitor the liquid level of the sewage tank can effectively avoid the failure of sewage monitoring due to the failure of one of the liquid level sensors, and further avoid the leakage of sewage. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of the utility model.

[0016] Figure 2 It is a cross-sectional view of the utility model.

[0017] Figure 3 It is a partial enlarged view of the utility model.

[0018] Figure 4 This is the installation diagram of the liquid level sensor.

[0019] In the figure: cabin 1, well edge 2, well cover 3, wellhead 4, deck 5, flange ring 6, sealing ring 7, U-shaped pull ring 8, mounting hole 9, casing 10, mounting pipe 11, mounting flange 12, liquid level sensor 13. DETAILED DESCRIPTION

[0020] The specific implementation of the utility model is further described in detail below with reference to the accompanying drawings:

[0021] like Figure 1 As shown, a watertight sewage tank structure of a cargo hold of an LNG carrier is composed of a tank body 1, a manhole edge 2, a manhole cover 3 and other components.

[0022] The cabin 1 is a sealed cabin, and the cabin 1 is connected to a sewage discharge pipe. The sewage generated during the operation of the ship enters the cabin 1 through the pipe for collection. Air permeable pipes connected to the main deck are provided on both sides of the top of the cabin 1 to ensure the air pressure balance in the cabin. A wellhead 4 is provided on the top of the cabin 1, and the wellhead 4 is elliptical. A well edge 2 is installed on the outside of the wellhead 4. The well edge 2 is a cylindrical structure, and the cross-sectional shape of the well edge 2 is the same as that of the wellhead 4. The bottom of the well edge 2 is fixedly welded to the top surface of the cabin top deck 5, and the bottoms of the inner and outer sides of the well edge 2 are respectively welded to the deck 5 to ensure water tightness. The inner size of the well edge 2 is larger than the size of the wellhead 4, so the welding point between the well edge 2 and the deck 5 deviates from the edge of the wellhead 4.

[0023] like Figure 2-3 As shown, a flange ring 6 is installed on the top end surface of the well edge 2, and the flange ring 6 covers the top surface of the well edge 2. The flange ring 6 is partially located on the inner side of the well edge 2 and partially located on the outer side of the well edge 2. The inner side and the outer side of the top of the well edge 2 are welded to the bottom surface of the flange ring 6 respectively, and watertightness is ensured. A circle of bolt holes is provided at the part of the flange ring 6 located on the outer side of the well edge.

[0024] The manhole cover 3 is installed on the top of the well edge 2 and supported on the top surface of the flange ring 6. The outer edge of the manhole cover 3 corresponds to the flange ring 6. The manhole cover 3 is provided with a circle of bolt holes corresponding to the bolt holes on the flange ring 6, and the manhole cover 3 and the flange ring 6 are fixedly connected by multiple bolts. In order to prevent sewage from overflowing, a sealing ring 7 is installed between the bottom surface of the manhole cover 3 and the top surface of the flange ring 6. In order to facilitate the movement of the manhole cover 3 during installation, a pair of U-shaped pull rings 8 are welded on the top surface of the manhole cover, and the U-shaped pull rings 8 are symmetrically distributed on both sides of the top surface of the manhole cover 3.

[0025] Four mounting holes 9 are provided in the middle of the top surface of the manhole cover 3, and liquid level sensors 13 are respectively installed in the four mounting holes 9, wherein the contacts of two liquid level sensors extend into the low liquid level in the cabin 1 to realize low liquid level monitoring, and the other two sensors extend into the high liquid level in the cabin 1 to realize high liquid level monitoring. In this way, it can be avoided that the monitoring fails due to the failure of a certain sensor.

[0026] like Figure 4As shown, the installation method of the liquid level sensor 13 is as follows: vertical sleeves 10 are respectively installed in the four installation holes 9 of the manhole cover, the outer diameter of the sleeve 10 corresponds to the inner diameter of the installation hole 9, and the sleeve 10 is respectively welded to the top and bottom surfaces of the manhole cover 3 to ensure water tightness. The two ends of the sleeve 10 extend out of the upper and lower sides of the manhole cover 3 respectively. A mounting pipe 11 is coaxially inserted in each sleeve 10, and the outer wall of the mounting pipe 11 is covered with a rubber sleeve. The rubber sleeve of the mounting pipe 11 is squeezed and matched with the inside of the sleeve 10 to form a watertightness. The two ends of the mounting pipe 11 extend out of the sleeve 10 respectively, and the upper end surface of the mounting pipe 11 is provided with a mounting flange 12 corresponding to the size of the liquid level sensor 13, and the liquid level sensor 13 is fixedly connected to the mounting flange 12 by bolts. The bottom surface of the liquid level sensor 13 closes the upper opening of the mounting pipe 11, and a sealing ring is installed between the bottom of the liquid level sensor 13 and the mounting flange 12.

[0027] During the construction of the ship in sections, the well edge 2, the well cover 3, the casing 10, the installation pipe 11, etc. are assembled and welded to form an integral part. In order to improve the corrosion resistance and other properties, the assembled integral part is galvanized. After the treatment, the integral part is installed at the wellhead 4. After the ship enters the dock, the liquid level sensor 13 is installed on the well cover 3.

Claims

1. A watertight sewage tank structure for a cargo hold of an LNG carrier, comprising a tank body, a wellhead is arranged on the upper part of the tank body, a well edge is arranged on the outer side of the wellhead, the well edge is a cylindrical structure, the bottom of the well edge is fixedly welded to the top surface of the tank top deck, the welding point between the well edge and the deck deviates from the edge of the wellhead, a well cover is installed on the top of the well edge, and the characteristics are: A flange ring is installed on the top of the well edge, and a circle of bolt holes is provided on the flange ring. A circle of bolt holes corresponding to the bolt holes on the flange ring is provided on the manhole cover. The manhole cover and the well edge are fixedly connected by multiple bolts, and a sealing ring is installed between the bottom surface of the manhole cover and the flange ring of the well edge; four mounting holes are provided on the top surface of the manhole cover, and liquid level sensors are respectively installed in the mounting holes, two of which extend into the low liquid level in the cabin, and the other two sensors extend to the high liquid level in the cabin, and the liquid level sensors are sealed and installed between the corresponding mounting holes.

2. The watertight sewage tank structure of the LNG carrier cargo hold according to claim 1, characterized in that: A vertical sleeve is installed in each of the mounting holes, the outer diameter of the sleeve corresponds to the inner diameter of the mounting hole, the sleeve is welded to the manhole cover, and both ends of the sleeve extend out of the upper and lower sides of the manhole cover respectively; a mounting tube is coaxially inserted in the sleeve, the outer wall of the mounting tube is covered with a rubber sleeve, the rubber sleeve of the mounting tube is squeezed and fitted with the inside of the sleeve, the upper end surface of the mounting tube is provided with a mounting flange, and the liquid level sensor is fixedly connected to the mounting flange.

3. The watertight sewage tank structure of the LNG carrier cargo hold according to claim 2 is characterized in that: The bottom surface of the liquid level sensor seals the upper opening of the sleeve, and a sealing ring is installed between the bottom of the liquid level sensor and the mounting flange.

4. The watertight sewage tank structure of the LNG carrier cargo hold according to claim 1, characterized in that: The bolt holes on the flange ring are located on the outside of the well edge.

5. The watertight sewage tank structure of the LNG carrier cargo hold according to claim 1, characterized in that: A pair of U-shaped pull rings are welded on the top surface of the manhole cover, and the U-shaped pull rings are distributed on both sides of the liquid level sensor.

6. A watertight sewage tank structure for a cargo hold of an LNG carrier according to any one of claims 1 to 5, characterized in that: The surfaces of the well edge, well cover, casing, installation pipe and U-shaped pull ring are all provided with zinc coating.

7. The watertight sewage tank structure of the LNG carrier cargo hold according to claim 1, characterized in that: Both sides of the cabin top are provided with ventilation ducts connected to the main deck.

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