B-type cabin guide pipe and bursting disc replacement structure

Abstract

The application discloses a type-B cabin guide pipe and a rupture disc replacement structure, which is applied to an independent liquid cargo cabin, wherein the independent liquid cargo cabin comprises a liquid cargo cabin shell and a liquid cargo cabin heat insulation layer; a leakage passage is arranged between the liquid cargo cabin shell and the liquid cargo cabin heat insulation layer; the guide pipe is arranged in the liquid cargo cabin heat insulation layer; the upper end of the guide pipe is fixed to the liquid cargo cabin shell; the guide pipe is provided with a guide hole for connecting the leakage passage; a liquid drip tray is arranged below the liquid cargo cabin heat insulation layer, and the lower end of the guide pipe is located in the inner cavity of the liquid drip tray; the lower end of the guide pipe is provided with a sponge rod, and the upper end of the sponge rod is arranged in the inner cavity of the guide pipe. The application cancels the conventional rupture disc setting and the nitrogen injection device in the leakage passage, simplifies the system, and has the advantages of simple structure, simple construction, simple maintenance and low cost.

Description

Technical Field

[0001] This invention relates to the field of marine technology, and in particular to a B-type cabin flow guide pipe and rupture disc replacement structure. Background Technology

[0002] According to the regulations of the International Maritime Organization, the main types of cargo tanks for bulk carriers of liquefied gases are membrane cargo tanks and independent cargo tanks. Independent cargo tanks can be further divided into three types: Type A, Type B, and Type C. Type A requires a complete secondary barrier, Type B requires a partial secondary barrier, and Type C is a pressure vessel and does not require a secondary barrier. The partial secondary barrier of a Type B tank requires a complete leakage channel to direct any cryogenic liquid that may leak from the cargo tank downwards into a drip tray.

[0003] Patent CN113401284A discloses a leaking liquid storage device for an independent liquid tank. The tank has an insulation layer on its outer wall, with a leakage channel between the tank and the insulation layer. A guide pipe is inserted through the insulation layer at the bottom of the tank, with its upper end connected to the leakage channel and its lower end connected to a relief valve. A liquid storage container is located below the relief valve. The storage container is divided into upper and lower halves; the lower half is located at the bottom of the hull, and the upper half is detachably connected to the lower half. The upper half includes an opening at the top, with the relief valve located within the opening. The relief valve in this patent is a rupture disc.

[0004] Patent CN115585297A discloses a temperature-sensitive rupture disc suitable for a Type B compartment. The Type B compartment has a flow guide pipe at its bottom, with the rupture disc connected to the end of the flow guide pipe via a flange. The rupture disc has a circular main flange and an end flange, with a rupture membrane sandwiched between the main flange and the end flange. Above the rupture membrane and at the center of the main flange, a double-layered metal sheet is fixed, with both ends of the double-layered metal sheet bolted to the main flange. The double-layered metal sheet consists of an upper metal sheet and a lower metal sheet, which are spot-welded together. The coefficient of thermal expansion of the upper metal sheet is lower than that of the lower metal sheet. Both the upper and lower metal sheets have a thickness of 0.5 mm, and a blade is fixed to one end of the lower metal sheet.

[0005] Patent CN111399572A discloses an environmental control system and method for a type B liquid cargo tank ancillary space. The environmental control system includes the following components: a first gas supply line connected between a nitrogen generator and the cargo tank space for supplying gas into the cargo tank space; a second gas supply line connected between the nitrogen generator and an insulating cavity for supplying gas into the insulating cavity; a first exhaust line connected between the cargo tank space and the outside atmosphere for discharging gas from the cargo tank space; and a second exhaust line connected between the insulating cavity and the outside atmosphere for discharging gas from the insulating cavity. Each of the first gas supply line, the second gas supply line, the first exhaust line, and the second exhaust line is equipped with a controlled valve. Pressure sensors are installed in both the cargo tank space and the insulating cavity. The nitrogen generator, the controlled valves, and the pressure sensors are all signal-connected to the environmental control unit.

[0006] The main drawback of existing technology is the presence of a rupture disc at the end of the guide pipe, which necessitates the addition of a pressure balancing system to the insulation system. This requires a nitrogen injection and control system within the leakage channel to achieve pressure balance at both ends of the rupture disc. Considering the effectiveness of the leakage channel's sealing in existing insulation systems, nitrogen injection will be necessary in the event of leakage during decades of daily operation of the ship. This structure increases construction, operation, and maintenance costs.

[0007] The existing diversion pipe is made of metal and is bolted to the bottom of the liquid cargo tank. Due to the high thermal conductivity of metal, the overall insulation system does not have sufficient cold preservation capacity, which poses a risk of cargo damage. Summary of the Invention

[0008] In order to overcome the above-mentioned defects in the existing technology, the present invention provides a B-type cabin flow guide tube and rupture disc replacement structure.

[0009] The present invention solves the above-mentioned technical problems through the following technical solution: A type B cargo tank guide pipe and rupture disc replacement structure are disclosed, which are applied to an independent cargo tank. The independent cargo tank includes a cargo tank shell and a cargo tank insulation layer covering the cargo tank shell. A leakage channel is provided between the cargo tank shell and the cargo tank insulation layer. The guide pipe is inserted through the cargo tank insulation layer. The guide pipe and the cargo tank insulation layer are sealed together. The upper end of the guide pipe is fixed to the cargo tank shell. The guide pipe has a guide hole for connecting the leakage channel. A drip tray is provided below the cargo tank insulation layer, and the lower end of the guide pipe is located in the inner cavity of the drip tray. The lower end of the guide pipe is provided with a sponge rod that can automatically detach under the weight of the cryogenic liquid and the pressure of the evaporating gas. The upper end of the sponge rod is inserted through the inner cavity of the guide pipe.

[0010] Furthermore, the flow guide hole is located above the insulation layer of the liquid cargo tank.

[0011] Furthermore, an adhesive is provided between the flow guide pipe and the insulation layer of the liquid cargo tank.

[0012] Furthermore, the adhesive used for bonding is a low-temperature resistant adhesive.

[0013] Furthermore, the bottom of the guide tube is located above the inner bottom surface of the drip tray, and there is a space between the bottom of the guide tube and the inner bottom surface of the drip tray for accommodating the sponge rod.

[0014] Furthermore, the sponge rod is connected to the guide tube by friction.

[0015] Furthermore, the sponge rod is an elastic composite material capable of absorbing and guiding liquids.

[0016] Furthermore, the outer shell of the liquid cargo tank is fixed with a strike plate, and the upper end of the flow guide pipe is fixed to the strike plate.

[0017] Furthermore, the guide tube is made of a low-temperature resistant composite material.

[0018] Furthermore, the guide tube and the stud are connected by welding after being heated with a hot air gun.

[0019] The beneficial effects of this invention are as follows: The invention has a simple structure, is easy to construct and maintain, and has low cost. It eliminates the need for conventional rupture discs, simplifying the system; it also eliminates the need for nitrogen injection devices in the leakage channel, further simplifying the system and saving on construction, operation, and maintenance costs. Furthermore, this invention eliminates the need for pressure control in the cargo hold space and the leakage channel space, simplifying the system; and it provides better insulation and cold preservation at the point where low-temperature liquid accumulates in the leakage channel, resulting in better sealing. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of a preferred embodiment of the present invention.

[0021] Figure 2 for Figure 1 Sectional view of AA. Detailed Implementation

[0022] This invention relates to the insulation system of the outer shell of a cryogenic liquid cargo tank, specifically to the arrangement of the leakage channel guide pipe and rupture disc of a Type B independent liquid cargo tank as specified by the International Maritime Organization (IMO).

[0023] This invention addresses the issues of poor insulation in the guide tube area, the need for a pressure balancing system on both sides of the rupture disc at the end of the guide tube, and the requirement for a nitrogen injection system and control system within the leakage channel. The entire insulation system is complex and poses certain reliability risks. This invention proposes a low-cost solution.

[0024] The purpose of this invention is to provide a diversion pipe and rupture disc alternative that has strong thermal insulation capabilities, low construction costs, low operation and maintenance costs, and high reliability of the leakage system.

[0025] The present invention will be described more clearly and completely below with reference to a preferred embodiment and the accompanying drawings.

[0026] like Figure 1 and Figure 2 As shown, a type B cargo tank guide pipe and rupture disc replacement structure is applied to an independent cargo tank. The independent cargo tank includes a cargo tank shell 11 and a cargo tank insulation layer 12 covering the cargo tank shell; a leakage channel 13 is provided between the cargo tank shell and the cargo tank insulation layer. It includes a guide pipe 14, which passes through the cargo tank insulation layer 12; the guide pipe 14 and the cargo tank insulation layer 12 are sealed together.

[0027] An adhesive 18 is provided between the flow guide pipe 14 and the insulation layer 12 of the liquid cargo tank. In this embodiment, the adhesive is a low-temperature resistant adhesive.

[0028] The upper end of the flow guide pipe 14 is fixedly connected to the outer shell 11 of the liquid cargo tank. The outer shell 11 of the liquid cargo tank is fixedly provided with a strike plate 19, and the upper end of the flow guide pipe is fixedly connected to the strike plate.

[0029] The guide tube 14 is made of low-temperature resistant composite material. The guide tube and the stud are connected by welding after heating with a hot air gun. The guide tube is sleeved on the stud.

[0030] The guide pipe 14 is provided with a guide hole 15 for connecting to the leakage channel. The guide hole 15 is located above the insulation layer of the liquid cargo tank.

[0031] Below the insulation layer 12 of the liquid cargo tank, there is a drip tray 16, and the lower end of the guide pipe 14 is located in the inner cavity of the drip tray; the lower end of the guide pipe 14 is provided with a sponge rod 17 that can automatically detach under the weight of the cryogenic liquid and the pressure of the evaporating gas.

[0032] The sponge rod 17 is an elastic composite material capable of absorbing and guiding liquids. The upper end of the sponge rod 17 passes through the inner cavity of the guide tube. No adhesive components are provided between the sponge rod and the guide tube. The sponge rod 17 is connected to the guide tube 14 by friction. The size of the sponge rod is larger than the inner diameter of the guide tube, and the sponge rod is compressed and inserted into the guide tube. The sponge rod can automatically detach under the weight of the cryogenic liquid and the pressure of the evaporating gas.

[0033] The bottom of the guide tube 14 is located above the inner bottom surface of the drip tray 16, and there is a space between the bottom of the guide tube and the inner bottom surface of the drip tray for accommodating the sponge rod.

[0034] In this invention, the outer shell of the cargo tank is covered with a cargo tank insulation layer, which provides a cooling effect. A leakage channel is provided between the outer shell and the insulation layer so that in the event of leakage, any overflowing cryogenic liquid will be collected at the bottom of the leakage channel and flow into a drip tray through a guide hole on a guide pipe. The upper end of the guide pipe is heated with a hot air gun and fitted onto a stud welded to the outer shell of the cargo tank. After returning to room temperature, it serves to secure the pipe. Then, low-temperature resistant adhesive is injected between the guide pipe and the insulation layer to achieve a sealed connection, preventing cryogenic liquid from leaking from the insulation layer. A sponge rod made of elastic composite material is inserted into the lower end of the guide pipe. The sponge rod automatically detaches under the weight of the cryogenic liquid and the pressure of the evaporating gas, thereby reducing the risk of tearing of the insulation layer due to the evaporation pressure of the cryogenic liquid and improving the safety of the entire insulation system.

[0035] In this invention, a sponge rod design is used at the end of the guide tube, replacing the traditional rupture disc; no pressure balancing system is required between the inlet and outlet of the guide tube; the sponge rod is made of an elastic material that can absorb and guide liquid, and the sponge rod at the end of the guide tube automatically detaches under the weight of the cryogenic liquid and the pressure of the evaporating gas. The leakage channel system at the inlet of the guide tube does not require a nitrogen injection system; the upper end of the guide tube is heated by a hot air gun and fitted onto a stud, then positioned after cooling; the guide tube is made of cryogenic composite material.

[0036] Compared with the prior art, the present invention has the following advantages: (1) Simple structure, simple construction, simple maintenance, and low cost; (2) The conventional rupture disc setting has been eliminated, simplifying the system; (3) The nitrogen injection device in the leakage channel was eliminated, which simplified the system and saved construction, operation and maintenance costs; (4) No pressure control is required for the cargo hold space and the leakage channel space, which simplifies the system; (5) The insulation and cold preservation effect of the low temperature liquid accumulation point in the leakage channel is better and the sealing performance is better.

[0037] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but all such changes and modifications fall within the scope of protection of the present invention.

Claims

1. A B-type tank flow guide pipe and rupture disc replacement structure, applied to an independent cargo tank, the independent cargo tank comprising a cargo tank shell and a cargo tank insulation layer covering the cargo tank shell; a leakage channel is provided between the cargo tank shell and the cargo tank insulation layer; characterized in that, It includes a flow guide pipe that passes through the insulation layer of the liquid cargo tank; the flow guide pipe and the insulation layer of the liquid cargo tank are sealed together; the upper end of the flow guide pipe is fixed to the outer shell of the liquid cargo tank; the flow guide pipe is provided with a flow guide hole for connecting the leakage channel; a drip tray is provided below the insulation layer of the liquid cargo tank, and the lower end of the flow guide pipe is located in the inner cavity of the drip tray; the lower end of the flow guide pipe is provided with a sponge rod that can automatically detach under the weight of the cryogenic liquid and the pressure of the evaporating gas, and the upper end of the sponge rod passes through the inner cavity of the flow guide pipe.

2. The replacement structure for the B-type cabin flow guide pipe and rupture disc as described in claim 1, characterized in that, The flow guide hole is located above the insulation layer of the liquid cargo tank.

3. The replacement structure for the B-type cabin flow guide pipe and rupture disc as described in claim 1, characterized in that, An adhesive is installed between the flow guide pipe and the insulation layer of the liquid cargo tank.

4. The replacement structure for the B-type cabin flow guide pipe and rupture disc as described in claim 3, characterized in that, The adhesive used for bonding is low-temperature resistant.

5. The replacement structure for the B-type cabin flow guide pipe and rupture disc as described in claim 1, characterized in that, The bottom of the guide tube is located above the inner bottom surface of the drip tray, and there is a space between the bottom of the guide tube and the inner bottom surface of the drip tray for accommodating the sponge rod.

6. The replacement structure for the B-type cabin flow guide pipe and rupture disc as described in claim 1, characterized in that, The sponge rod is connected to the guide tube by friction.

7. The replacement structure for the B-type cabin flow guide pipe and rupture disc as described in claim 1, characterized in that, The sponge rod is an elastic composite material capable of absorbing and guiding liquids.

8. The replacement structure for the B-type cabin flow guide pipe and rupture disc as described in claim 1, characterized in that, The outer shell of the liquid cargo tank is fixed with a strike plate, and the upper end of the flow guide pipe is fixed to the strike plate.

9. The replacement structure for the B-type cabin flow guide pipe and rupture disc as described in claim 8, characterized in that, The flow guide tube is made of low-temperature resistant composite material.

10. The replacement structure for the B-type cabin flow guide pipe and rupture disc as described in claim 9, characterized in that, The guide tube and the stud are connected by welding after being heated with a hot air gun.

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