Gas pressure control method for ships and liquid cargo tanks

Abstract

The present invention discloses a method for controlling air pressure in a ship and a liquid cargo tank. The ship includes a liquid cargo tank containment system, a cabin for storing the liquid cargo tank containment system, and an air pressure control device. The liquid cargo tank containment system includes an insulating layer and a liquid cargo tank, an insulating space is formed between the insulating layer and the liquid cargo tank. The outer side of the insulating layer and the inner side of the cabin form a liquid cargo tank space. The insulating layer is provided with a balancing hole that passes through the insulating space and the liquid cargo tank space. The air pressure control device controls the opening or closing of an insulating space air inlet assembly, a liquid cargo tank space air inlet assembly, and a liquid cargo tank space air outlet assembly according to a first air pressure value and a second air pressure value collected. The liquid cargo tank air pressure control method is applied to the above ship. Maintaining balance between the insulating space and the liquid cargo tank space at all times can reduce the stress on the insulating layer, effectively reducing the risk of damage to the insulating layer and deformation of the cabin hull structure. In addition, the liquid cargo tank space can be simply and quickly aerated by replacing the introduced inert protective gas with air.

Description

Technical Field

[0001] The present invention relates to the field of liquid cargo tanks, and in particular to a ship and a method for controlling air pressure in a liquid cargo tank. Background Art

[0002] A cargo tank is an independent compartment on a ship specifically used for loading cryogenic liquefied gas fuel tanks or cryogenic cargo. It can be used to load cryogenic liquids such as liquefied natural gas (LNG), ethane, ethylene, and liquid ammonia. The cargo tank is covered with a thermal insulation layer, and an insulating space is formed between the cargo tank and the insulation layer, which can be used as a circulation channel in the event of a leak in the cargo tank. The cargo tank is located in the cabin of the ship, and the cabin space where the cargo tank is located is called the cargo tank space. When the ship is carrying cryogenic liquids, the insulating space of the cargo tank and the cargo tank space are in an inert environment; when the cargo tank needs to be repaired, the insulating space and the cabin space are converted to an atmospheric environment, and people can enter the space without restriction.

[0003] Type B tanks are a commonly used type of liquid cargo tank. They are known as Partially Secondary Contained Independent Type B Tanks (abbreviated as Type B tanks). Type B tanks include an insulation layer covering the exterior of the tank, which is a plate-type structure. The insulation layer can withstand very limited air pressure, necessitating precise pressure control within the insulation space. The cabin space within which the liquid cargo tank is located also has stringent requirements for ambient air pressure. Existing tank insulation structures struggle to meet these standards and are prone to damage due to overpressure. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the defect in the prior art that the air pressure of the insulation space and cabin space of the liquid cargo tank is difficult to control, which easily leads to damage of the insulation layer, and provide a method for controlling the air pressure of a ship and a liquid cargo tank.

[0005] The present invention solves the above technical problems through the following technical solutions:

[0006] The present invention provides a ship, which includes a liquid cargo tank containment system, a cabin for storing the liquid cargo tank containment system, and an air pressure control device; the liquid cargo tank containment system includes an insulation layer and a liquid cargo tank, the insulation layer wraps the liquid cargo tank, an insulation space is formed between the insulation layer and the liquid cargo tank, and a first inert protective gas is filled in the insulation space; the outer side of the insulation layer and the interior of the cabin form a liquid cargo tank space, and the liquid cargo tank space is filled with a second inert protective gas; the first air pressure in the insulation space is greater than the second air pressure in the liquid cargo tank space; The insulating layer is provided with a balancing hole, and the two ends of the balancing hole are respectively connected to the insulating space and the liquid cargo tank space; the air pressure control device includes a first air pressure sensor, a second air pressure sensor, a control unit, an insulating space air inlet assembly, a liquid cargo tank space air inlet assembly and a liquid cargo tank space air outlet assembly; the insulating space air inlet assembly is in a normally open state, the liquid cargo tank space air inlet assembly and the liquid cargo tank space air outlet assembly are in a normally closed state, the insulating space air inlet assembly is used to replenish the first inert protective gas to the insulating space, and the liquid cargo tank space air inlet assembly The cargo tank space is configured to replenish the second inert protective gas to the cargo tank space, and the cargo tank space air outlet assembly is configured to discharge the second inert protective gas in the cargo tank space to the outside of the compartment; the first air pressure sensor is configured to detect a first air pressure value in the insulating space and transmit the detection data to the control unit, and the second air pressure sensor is configured to detect a second air pressure value in the cargo tank space and transmit the detection data to the control unit; the control unit is configured to control the insulating space air inlet assembly, the cargo tank space air inlet assembly, and the cargo tank space air outlet assembly to be opened or closed according to the first and second air pressure values ​​received; when the first air pressure value is greater than a first preset air pressure value, the control unit is configured to control the insulating space air inlet assembly to be closed; when the second air pressure value is greater than the second preset air pressure value, the control unit is configured to control the cargo tank space air outlet assembly to be activated; when the pressure difference between the first and second air pressure values ​​exceeds a preset pressure difference value, the control unit is configured to control the insulating space air inlet assembly to be closed and the cargo tank space air inlet assembly to be activated.

[0007] In this solution, under normal conditions, the insulation space air inlet assembly slowly and continuously delivers a first inert protective gas into the insulation space, maintaining an inert environment within the insulation space. The first inert protective gas within the insulation space then flows out into the cargo tank space through a balancing hole provided in the insulation layer, thereby balancing the air pressure between the insulation space and the cargo tank space. Simultaneously, a first pressure preset value and a second pressure preset value are preset via a first pressure sensor and a second pressure sensor, respectively. When the actual pressure exceeds the preset pressure values, an adjustment operation is performed: when the first pressure sensor exceeds the first pressure preset value, the insulation space air inlet assembly is closed to suspend air supply to the insulation space, thereby reducing the pressure within the insulation space through the balancing hole; when the second pressure sensor exceeds the second pressure preset value, the cargo tank space air outlet assembly is opened to discharge excess gas from the cargo tank space, thereby reducing the pressure; and when the pressure difference between the first and second pressure values ​​exceeds the preset pressure difference value, air is added to the cargo tank space to achieve balance. Each of the above components is controlled by a control unit. Maintaining a constant balance between the insulation space and the cargo tank space reduces stress on the insulation layer, effectively lowering the risk of insulation damage. This also prevents excessive pressure in the cargo tank space, effectively reducing the risk of compressive deformation of the hull structure. Furthermore, simply replacing the inert shielding gas with air allows for a simple and quick aeration of the cargo tank space.

[0008] Preferably, the insulating layer is further provided with an air inlet hole, the two ends of which are respectively connected to the insulating space and the liquid cargo tank; the insulating space air inlet assembly comprises a first air source, an insulating space air inlet pipe and an insulating space air inlet valve, the first air source is communicated with the insulating space air inlet pipe, the insulating space air inlet pipe is connected to the air inlet hole, the insulating space air inlet valve is provided on the insulating space air inlet pipe and is electrically connected to the control unit; the liquid cargo tank air inlet assembly comprises a second air source, a liquid cargo tank air inlet pipe and a liquid cargo tank air inlet valve. The tank space air inlet valve, the second air source component is communicated with the insulating space air inlet pipe, the liquid cargo tank space air inlet pipe is connected to the cabin, the liquid cargo tank space air inlet valve is arranged on the liquid cargo tank space air inlet pipe and is electrically connected to the control unit; the liquid cargo tank space air outlet assembly includes a liquid cargo tank space air outlet pipe and a liquid cargo tank space air outlet valve, the two ends of the liquid cargo tank space air outlet pipe are respectively communicated with the interior of the cabin and the outside of the cabin, the liquid cargo tank space air outlet valve is arranged on the liquid cargo tank space air outlet pipe and is electrically connected to the control unit.

[0009] In this solution, the insulating space air inlet assembly, the liquid cargo tank space, and the liquid cargo tank space air outlet assembly are respectively composed of pipe and valve structures. By controlling the opening and closing of each valve by the control unit, the insulating space air inlet assembly, the liquid cargo tank space, and the liquid cargo tank space air outlet assembly can be easily opened and closed.

[0010] Preferably, the balancing hole is arranged at the upper part of the insulating layer, and the air inlet hole is arranged at the bottom of the insulating layer; the first air pressure sensor is arranged in the air inlet pipe of the insulating space; and / or the second air pressure sensor is arranged in the air inlet pipe of the liquid cargo tank.

[0011] In this solution, the insulation space air intake assembly supplies air into the insulation space through an air intake hole at the bottom of the insulation layer, which then overflows through a balancing hole at the top of the insulation layer. This structure facilitates the diffusion of the first inert shielding gas and fills the entire insulation space. By installing a first pressure sensor and a second pressure sensor on the insulation space air intake duct and the cargo tank space air intake duct, respectively, the air pressure in the insulation space and cargo tank spaces can be easily monitored, achieving precise ambient pressure control with a high degree of automation and avoiding risks caused by human error.

[0012] Preferably, the air pressure control device also includes a first safety protection device, which includes an insulating space air pressure safety valve and a first safety protection pipe, the two ends of the insulating space air pressure safety valve are respectively connected to the insulating space air inlet pipe and the first safety protection pipe, and the other end of the first safety protection pipe is connected to the outside of the cabin; the insulating space air pressure safety valve can be set to a first safety air pressure preset value, and when the first air pressure value is greater than the first safety air pressure preset value, the insulating space air pressure safety valve automatically opens; and / or, the air pressure control device also includes a second safety protection device, which includes a liquid cargo tank space air pressure safety valve and a second safety protection pipe, the two ends of the liquid cargo tank space air pressure safety valve are respectively connected to the liquid cargo tank space and the second safety protection pipe, and the other end of the second safety protection pipe is connected to the outside of the cabin; the liquid cargo tank space air pressure safety valve can be set to a second safety air pressure preset value, and when the second air pressure value is greater than the second safety air pressure preset value, the liquid cargo tank space air pressure safety valve automatically opens.

[0013] In this solution, if the air pressure in the insulation space exceeds the first preset safety pressure value, it may be due to a fault in the insulation space air inlet assembly. The first safety protection device will activate to prevent air from being supplied to the insulation space, thereby preventing further pressure increases in the insulation space and allowing the pressure in the insulation space to return to equilibrium after excess gas overflows from the balancing hole. If the air pressure in the cargo tank space exceeds the second preset safety pressure value, it may be due to a fault in the cargo tank space air outlet assembly. The second safety protection device will activate to ensure timely discharge of gas from the cargo tank space, preventing further pressure increases in the cargo tank space and allowing the pressure in the cargo tank space to return to equilibrium after excess gas is discharged from the second safety protection duct.

[0014] Preferably, the air pressure control device also includes a pressure differential sensor, and the first air pressure sensor and the second air pressure sensor are both electrically connected to the pressure differential sensor, and the pressure differential sensor is used to detect the pressure difference between the first air pressure value and the second air pressure value and transmit the detection data to the control unit.

[0015] In this solution, the differential pressure sensor can monitor the air pressure difference, provide data support, and ensure the normal operation of the air pressure control device.

[0016] Preferably, the ship further includes a gas detection device and an alarm, wherein the detection end of the gas detection device is arranged close to the balancing hole, the gas detection device is electrically connected to the alarm, and the gas detection device is used to detect combustible gas at the balancing hole.

[0017] In this solution, when a liquid cargo tank leaks, the flammable gas in the liquid cargo tank evaporates into the insulating space and escapes from the balancing hole along with the first inert protective gas. The gas detection device arranged near the balancing hole can detect the flammable gas leakage in time and sound an alarm.

[0018] The present invention also provides a liquid cargo tank air pressure control method, which is applied to the ship as described above, and the liquid cargo tank air pressure control method includes: using the first air pressure sensor to detect a first air pressure value in the insulating space, and using the second air pressure sensor to detect a second air pressure value in the liquid cargo tank space; judging whether the first air pressure value exceeds the first air pressure preset value; if so, closing the insulating space air inlet component by the control unit; if not, keeping the insulating space air inlet component normally open; judging whether the second air pressure value exceeds the second air pressure preset value; if so, opening the liquid cargo tank space air outlet component by the control unit; if not, keeping the liquid cargo tank space air outlet component normally closed; judging whether the pressure difference between the first air pressure value and the second air pressure value exceeds the preset pressure difference value, if so, controlling the insulating space air inlet component to be closed and controlling the liquid cargo tank space air inlet component to be started by the control unit; if not, keeping the insulating space air inlet component normally open and keeping the liquid cargo tank space air inlet component normally closed.

[0019] In this solution, the insulation space air inlet assembly slowly and continuously delivers a first inert protective gas into the insulation space, maintaining an inert environment within the insulation space. The air pressure in the insulation space and the cargo tank space are balanced via a balancing hole provided in the insulation layer. Furthermore, a first pressure sensor and a second pressure sensor are used to preset a first pressure value and a second pressure value, respectively. When the actual pressure exceeds the preset pressure values, an adjustment operation is performed: when the first pressure sensor exceeds the first pressure value, the insulation space air inlet assembly is closed to suspend air supply to the insulation space, reducing the pressure within the insulation space via the balancing hole. When the second pressure sensor exceeds the second pressure value, the cargo tank space air outlet assembly is opened to discharge excess gas from the cargo tank space, thereby reducing the pressure. When the pressure difference between the first and second pressure values ​​exceeds the preset pressure difference, air is added to the cargo tank space to achieve balance. Each of the above components is controlled by a control unit.

[0020] Preferably, when the first air pressure value exceeds the first air pressure preset value, the step of closing the insulating space air inlet component by the control unit specifically includes: the control unit controls the insulating space air inlet component to be closed until the first air pressure value satisfies less than or equal to the first air pressure preset value, and the control unit controls the insulating space air inlet component to be opened; and / or, when the second air pressure value exceeds the second air pressure preset value, the step of opening the liquid cargo tank air outlet component by the control unit specifically includes: the control unit controls the liquid cargo tank air outlet component to be opened until the second air pressure value satisfies less than or equal to the second air pressure preset value. When the pressure difference between the first air pressure value and the second air pressure value exceeds the preset pressure difference value, the control unit controls the liquid cargo tank air outlet component to close; and / or when the pressure difference between the first air pressure value and the second air pressure value exceeds the preset pressure difference value, the step of controlling the insulating space air inlet component to close and controlling the liquid cargo tank air inlet component to start by the control unit specifically includes: the control unit controls the insulating space air inlet component to close and controls the liquid cargo tank air inlet component to start until the pressure difference between the first air pressure value and the second air pressure value is less than or equal to the preset pressure difference value, and the control unit controls the insulating space air inlet component to open and controls the liquid cargo tank air inlet component to close.

[0021] In this solution, the insulating space air inlet assembly is closed until the first air pressure value meets or exceeds the first air pressure preset value. The control unit controls the insulating space air inlet assembly to open to ensure that the first inert protective gas is supplied as soon as the insulating space air pressure value reaches the first air pressure preset value, thereby preventing the concentration of the first inert protective gas in the inert environment from being too low. The cargo tank space air outlet assembly is opened until the second air pressure value meets or exceeds the second air pressure preset value. The control unit controls the cargo tank space air outlet assembly to close to ensure that excess gas in the cargo tank space is promptly closed after discharge, thereby preventing excessive discharge of the second inert protective gas in the cargo tank space from causing low air pressure and gas waste. When the pressure difference between the first air pressure value and the second air pressure value is less than or equal to the preset pressure difference value, the control unit controls the insulating space air inlet assembly to open and controls the cargo tank space air inlet assembly to close to prevent excessive gas supply to the insulating space or cargo tank space from disrupting the air pressure balance.

[0022] Preferably, in the step of determining whether the pressure difference between the first air pressure value and the second air pressure value exceeds the preset pressure difference value, the pressure difference between the first air pressure value and the second air pressure value is acquired by a pressure difference sensor.

[0023] In this solution, the differential pressure sensor can monitor the air pressure difference, provide data support, and ensure the normal operation of the air pressure control device.

[0024] Preferably, in the step of judging whether the first air pressure value exceeds the first air pressure preset value; if so, in the step of closing the insulating space air inlet component by the control unit, the insulating space air pressure safety valve is set to a first safety air pressure preset value, if after the control unit closes the insulating space air inlet component, the first air pressure value is greater than the first safety air pressure preset value, the insulating space air pressure safety valve automatically opens until the first air pressure value satisfies less than or equal to the first safety air pressure preset value; and / or, in the step of judging whether the second air pressure value exceeds the second air pressure preset value; if so, in the step of opening the liquid cargo tank air outlet component by the control unit, the liquid cargo tank air pressure safety valve is set to a second safety air pressure preset value, if after the control unit opens the liquid cargo tank air outlet component, the second air pressure value is greater than the second safety air pressure preset value, the liquid cargo tank air pressure safety valve opens until the second air pressure value satisfies less than or equal to the second safety air pressure preset value.

[0025] In this solution, if the air pressure in the insulation space exceeds the first preset safety pressure value, it may be due to a fault in the insulation space air inlet assembly. The first safety protection device will activate to prevent air from being supplied to the insulation space, thereby preventing further pressure increases in the insulation space and allowing the pressure in the insulation space to return to equilibrium after excess gas overflows from the balancing hole. If the air pressure in the cargo tank space exceeds the second preset safety pressure value, it may be due to a fault in the cargo tank space air outlet assembly. The second safety protection device will activate to ensure timely discharge of gas from the cargo tank space, preventing further pressure increases in the cargo tank space and allowing the pressure in the cargo tank space to return to equilibrium after excess gas is discharged from the second safety protection duct.

[0026] The positive progress effect of the present invention is:

[0027] The present invention relates to a method for controlling air pressure in a ship and cargo tank. Under normal conditions, an insulated space air intake assembly slowly and continuously delivers a first inert protective gas into the insulated space, maintaining an inert environment within the insulated space. The first inert protective gas in the insulated space then flows out into the cargo tank through a balancing hole provided in the insulation layer, thereby balancing the air pressure between the insulated space and the cargo tank. Simultaneously, a first pressure preset value and a second pressure preset value are respectively preset by a first pressure sensor and a second pressure sensor. When the actual pressure exceeds the preset pressure values, an adjustment operation is performed: when the first pressure sensor exceeds the first pressure preset value, the insulated space air intake assembly is closed to suspend air supply to the insulated space, thereby reducing the pressure within the insulated space through the balancing hole; when the second pressure sensor exceeds the second pressure preset value, the cargo tank air outlet assembly is opened to discharge excess gas from the cargo tank, thereby reducing the pressure; and when the pressure difference between the first and second pressure values ​​exceeds the preset pressure difference value, air is supplied to the cargo tank to achieve balance. Each of the above components is controlled by a control unit. Maintaining a constant balance between the insulation space and the cargo tank space reduces stress on the insulation layer, effectively lowering the risk of insulation damage. This also prevents excessive pressure in the cargo tank space, effectively reducing the risk of compressive deformation of the hull structure. Furthermore, simply replacing the inert shielding gas with air allows for a simple and quick aeration of the cargo tank space. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A schematic structural diagram of a liquid cargo tank according to an embodiment of the present invention

[0029] Figure 2 Schematic diagram of the partial structure of the liquid cargo tank according to an embodiment of the present invention

[0030] Figure 3 Flow chart of the liquid cargo tank air pressure control method according to an embodiment of the present invention

[0031] Description of reference numerals:

[0032] Cargo tank containment system 1

[0033] Cabin 2

[0034] Air pressure control device 3

[0035] Insulation layer 4

[0036] Cargo tank 5

[0037] Insulation space 6

[0038] Cargo tank space 7

[0039] Balance hole 8

[0040] Air Inlet 9

[0041] First air pressure sensor 10

[0042] Second air pressure sensor 11

[0043] Control unit 12

[0044] Differential pressure sensor 13

[0045] Insulation space air intake assembly 14

[0046] Cargo tank space air intake assembly 15

[0047] Cargo tank space air outlet assembly 16

[0048] First safety protection device 17

[0049] Second safety protection device 18

[0050] Gas detection device 19 DETAILED DESCRIPTION

[0051] A preferred embodiment is given below and the present invention is described more clearly and completely in conjunction with the accompanying drawings.

[0052] This embodiment provides a ship, such as Figure 1 and Figure 2 As shown, it includes a cargo tank containment system 1, a compartment 2 for storing the cargo tank containment system 1, and an air pressure control device 3. The cargo tank containment system 1 is a fuel storage device including cargo tank connections, used to safely store and transport liquefied gas at extremely low temperatures. The cargo tank containment system 1 includes an insulation layer 4 and a cargo tank 5.

[0053] The cargo tank 5 is a partially secondary contained independent type B tank, referred to as a type B tank. An insulating layer 4 encloses the cargo tank 5, forming an insulating space 6 between the insulating layer 4 and the cargo tank 5. This insulating space 6 is filled with a first inert protective gas. The outer side of the insulating layer 4 and the interior of the cabin 2 form a cargo space 7, which is filled with a second inert protective gas. The first gas pressure within the insulating space 6 is greater than the second gas pressure within the cargo space 7.

[0054] A balancing hole 8 is provided on the insulating layer 4, and the two ends of the balancing hole 8 are respectively connected to the insulating space 6 and the liquid cargo tank space 7; the air pressure control device 3 includes a first air pressure sensor 10, a second air pressure sensor 11, a control unit 12, an insulating space air inlet assembly 14, a liquid cargo tank space air inlet assembly 15 and a liquid cargo tank space air outlet assembly 16; the insulating space air inlet assembly 14 is in a normally open state, and the liquid cargo tank space air inlet assembly 15 and the liquid cargo tank space air outlet assembly 16 are in a normally closed state. The insulating space air inlet assembly 14 is used to replenish the first inert protective gas to the insulating space 6, the liquid cargo tank space air inlet assembly 15 is used to replenish the second inert protective gas to the liquid cargo tank space 7, and the liquid cargo tank space air outlet assembly 16 is used to discharge the second inert protective gas in the liquid cargo tank space 7 to the outside of the cabin 2.

[0055] The first air pressure sensor 10 is used to detect a first air pressure value in the insulating space 6 and transmit the detection data to the control unit 12, and the second air pressure sensor 11 is used to detect a second air pressure value in the liquid cargo tank space 7 and transmit the detection data to the control unit 12; the control unit 12 is configured to control the opening or closing of the insulating space air inlet component 14, the liquid cargo tank space air inlet component 15 and the liquid cargo tank space air outlet component 16 according to the collected first air pressure value and the second air pressure value.

[0056] When the first air pressure value is greater than the first air pressure preset value, the control unit 12 is used to control the insulation space air intake component 14 to close; when the second air pressure value is greater than the second air pressure preset value, the control unit 12 is used to control the liquid cargo tank air outlet component 16 to start; when the pressure difference between the first air pressure value and the second air pressure value exceeds the preset pressure difference value, the control unit 12 is used to control the insulation space air intake component 14 to close and control the liquid cargo tank air intake component 15 to start.

[0057] In this way, under normal conditions, the insulating space air inlet assembly 14 slowly and continuously delivers the first inert protective gas into the insulating space 6, so that the insulating space 6 maintains an inert environment. The first inert protective gas in the insulating space 6 flows out into the liquid cargo tank space 7 through the balancing hole 8 opened on the insulating layer 4 to balance the air pressure between the insulating space 6 and the liquid cargo tank space 7. At the same time, a first pressure sensor 10 and a second pressure sensor 11 are used to preset a first pressure value and a second pressure value, respectively. When the actual pressure exceeds the preset pressure values, an adjustment operation is performed: when the first pressure sensor 10 exceeds the first pressure value, the insulating space air inlet assembly 14 is closed to suspend air supply to the insulating space 6, thereby reducing the pressure within the insulating space 6 through the balancing hole 8; when the second pressure sensor 11 exceeds the second pressure value, the liquid cargo tank space air outlet assembly 16 is opened to discharge excess gas from the liquid cargo tank space 7 to reduce the pressure; when the pressure difference between the first and second pressure values ​​exceeds the preset pressure difference, air is added to the liquid cargo tank space 7 to achieve equilibrium. These components are controlled by the control unit 12. Maintaining equilibrium between the insulating space 6 and the liquid cargo tank space 7 at all times can reduce the stress on the insulating layer 4, effectively reducing the risk of damage to the insulating layer 4. At the same time, excessive pressure in the liquid cargo tank space 7 is prevented, effectively reducing the risk of compression and deformation of the hull structure of the cabin 2. In addition, the cargo tank space 7 can be aerated simply and quickly by simply replacing the inert protective gas introduced into the tank with air.

[0058] The first inert shielding gas and the second inert shielding gas can be different gases, such as helium, argon, and nitrogen. Different types of inert shielding gases will not chemically react with each other. In this embodiment, the first inert shielding gas and the second inert shielding gas are both nitrogen.

[0059] In this embodiment, the insulating layer 4 is further provided with an air inlet 9, the two ends of which are respectively connected to the insulating space 6 and the liquid cargo tank space 7; the insulating space air inlet assembly 14 includes a first air source component, an air inlet pipe for the insulating space 6 and an air inlet valve for the insulating space 6, the first air source component is communicated with the air inlet pipe for the insulating space 6, the air inlet pipe for the insulating space 6 is connected to the air inlet 9, the air inlet valve for the insulating space 6 is provided on the air inlet pipe for the insulating space 6 and is electrically connected to the control unit 12; the liquid cargo tank space air inlet assembly 15 includes a second air source component, an air inlet pipe for the liquid cargo tank space The second gas source is connected to the air inlet pipe of the insulating space, the air inlet pipe of the cargo tank space is connected to the cabin 2, the air inlet valve of the cargo tank space is arranged on the air inlet pipe of the cargo tank space and is electrically connected to the control unit 12; the air outlet assembly 16 of the cargo tank space includes an air outlet pipe of the cargo tank space and an air outlet valve of the cargo tank space, the two ends of the air outlet pipe of the cargo tank space are connected to the interior of the cabin 2 and the outside of the cabin 2 respectively, the air outlet valve of the cargo tank space is arranged on the air outlet pipe of the cargo tank space and is electrically connected to the control unit 12.

[0060] The insulating space air inlet assembly 14 delivers air into the insulating space 6 through the air inlet holes 9 at the bottom of the insulating layer 4, which then overflows from the balancing holes 8 at the top of the insulating layer 4. This structure facilitates the diffusion of the first inert protective gas and fills the entire insulating space 6. Furthermore, the insulating space air inlet assembly 14, the cargo tank space 7, and the cargo tank space air outlet assembly 16 each comprise a structure of pipes and valves. Controlling the opening and closing of each valve via the control unit 12 facilitates the opening and closing of the insulating space air inlet assembly 14, the cargo tank space 7, and the cargo tank space air outlet assembly 16.

[0061] The first and second air source components can be the same air source component. In this embodiment, the first and second air source components are the same air source component, which is connected to the ship's own nitrogen system. This nitrogen system is typically a permanent device on dual-fuel ships or liquid cargo ships.

[0062] Specifically, the balancing hole 8 is provided at the top of the insulating layer 4, and the air inlet 9 is provided at the bottom of the insulating layer 4. The two air pressure sensors can be arranged in the following three ways: first, the first air pressure sensor 10 is arranged in the air inlet duct of the insulating space; second, the second air pressure sensor 11 is arranged in the air inlet duct of the liquid cargo tank space; third, the first air pressure sensor 10 is arranged in the air inlet duct of the insulating space, and the second air pressure sensor 11 is arranged in the air inlet duct of the liquid cargo tank space. The third arrangement is preferred.

[0063] In this way, by arranging the first air pressure sensor 10 and the second air pressure sensor 11 on the air inlet pipe of the insulating space and the air inlet pipe of the liquid cargo tank space respectively, it is convenient to detect the air pressure values ​​of the insulating space 6 and the liquid cargo tank space 7, thereby realizing the precise control function of the ambient pressure, having a high degree of automation, and avoiding the risks caused by human operating errors.

[0064] Specifically, the air pressure control device 3 further includes a first safety protection device 17, which includes an insulating space air pressure safety valve and a first safety protection pipe. The two ends of the insulating space air pressure safety valve are respectively connected to the insulating space air inlet pipe and the first safety protection pipe, and the other end of the first safety protection pipe is connected to the outside of the cabin 2. When the first air pressure value exceeds the first safety air pressure preset value for a preset time, the insulating space air pressure safety valve automatically opens. Alternatively, the air pressure control device 3 further includes a second safety protection device 18, which includes a liquid cargo tank space air pressure safety valve and a second safety protection pipe. The two ends of the liquid cargo tank space air pressure safety valve are respectively connected to the liquid cargo tank space 7 and the second safety protection pipe, and the other end of the second safety protection pipe is connected to the outside of the cabin 2. When the second air pressure value exceeds the second safety air pressure preset value for a preset time, the liquid cargo tank space air pressure safety valve automatically opens. Alternatively, the air pressure control device 3 may include the first safety protection device 17 and the second safety protection device 18.

[0065] The first preset safety pressure value is greater than the first preset pressure value and less than the pressure withstand by the insulation layer 4; the second preset safety pressure value is greater than the second preset pressure value and less than the pressure withstand by the structure of the cabin 2. The insulation space pressure safety valve and the liquid cargo tank pressure safety valve are commonly used pressure safety valves on ships and are part of the prior art, so this patent does not discuss them in detail.

[0066] Thus, if the air pressure in the insulating space 6 exceeds the first preset safety pressure value, it may be due to a fault in the insulating space air inlet assembly 14. The first safety protection device 17 is activated to prevent air from being supplied to the insulating space 6, thereby preventing the air pressure in the insulating space 6 from continuing to rise and restoring equilibrium after excess gas overflows from the balancing hole 8. If the air pressure in the cargo tank space 7 exceeds the second preset safety pressure value, it may be due to a fault in the cargo tank space air outlet assembly 16. The second safety protection device 18 is activated to ensure that the gas in the cargo tank space 7 is discharged in a timely manner, thereby preventing the air pressure in the cargo tank space 7 from continuing to rise and restoring equilibrium after excess gas is discharged from the second safety protection pipe.

[0067] Specifically, the air pressure control device 3 also includes a pressure difference sensor 13. The first air pressure sensor 10 and the second air pressure sensor 11 are both electrically connected to the pressure difference sensor 13. The pressure difference sensor 13 is used to detect the pressure difference between the first air pressure value and the second air pressure value and transmit the detection data to the control unit 12.

[0068] In this way, the pressure difference sensor 13 can monitor the air pressure difference, provide data support, and ensure the normal operation of the air pressure control device 3.

[0069] In this embodiment, the differential pressure sensor 13 may be integrated into the control unit 12 .

[0070] Specifically, the ship also includes a gas detection device 19 and an alarm. The detection end of the gas detection device 19 is arranged close to the balancing hole 8. The gas detection device 19 is electrically connected to the alarm. The gas detection device 19 is used to detect combustible gas at the balancing hole 8.

[0071] In this way, when a leak occurs in the liquid cargo tank, the flammable gas in the liquid cargo tank 5 evaporates into the insulating space 6 and escapes from the balancing hole 8 along with the first inert protective gas. The gas detection device 19 arranged near the balancing hole 8 can detect the flammable gas leakage in time and sound an alarm.

[0072] In this embodiment, the gas detection device 19 may also be provided in the gas outlet pipeline of the liquid cargo tank space, for detecting the combustible gas at the gas outlet pipeline of the liquid cargo tank space.

[0073] This embodiment also provides a method for controlling the gas pressure in a liquid cargo tank, which is applied to the above-mentioned ship. Figure 3 As shown, the cargo tank gas pressure control method includes:

[0074] A first air pressure sensor 10 is used to detect a first air pressure value in the insulating space 6, and a second air pressure sensor 11 is used to detect a second air pressure value in the cargo tank space 7;

[0075] Determine whether the first air pressure value exceeds the first air pressure preset value; if so, close the insulating space air intake component 14 through the control unit 12; if not, keep the insulating space air intake component 14 normally open;

[0076] Determine whether the second air pressure value exceeds the second air pressure preset value; if so, open the liquid cargo tank space air outlet component 16 through the control unit 12; if not, keep the liquid cargo tank space air outlet component 16 normally closed;

[0077] Determine whether the pressure difference between the first air pressure value and the second air pressure value exceeds the preset pressure difference value. If so, the control unit 12 controls the insulation space air intake component 14 to be closed and the liquid cargo tank air intake component 15 to be started; if not, keep the insulation space air intake component 14 normally open and keep the liquid cargo tank air intake component 15 normally closed.

[0078] In this manner, the insulating space air inlet assembly 14 slowly and continuously delivers the first inert protective gas into the insulating space 6, maintaining an inert atmosphere within the insulating space 6. The air pressure in the insulating space 6 and the cargo tank space 7 are balanced via the balancing holes 8 provided in the insulating layer 4. Simultaneously, a first preset pressure value and a second preset pressure value are preset via the first pressure sensor 10 and the second pressure sensor 11, respectively. When the actual pressure exceeds the preset pressure values, an adjustment operation is performed: when the first pressure sensor 10 exceeds the first preset pressure value, the insulating space air inlet assembly 14 is closed to suspend air supply to the insulating space 6, reducing the pressure within the insulating space 6 via the balancing holes 8. When the second pressure sensor 11 exceeds the second preset pressure value, the cargo tank space air outlet assembly 16 is opened to discharge excess gas from the cargo tank space 7, thereby reducing the pressure. When the pressure difference between the first and second pressure values ​​exceeds the preset pressure difference value, air is added to the cargo tank space 7 to achieve equilibrium. These components are controlled by a control unit 12.

[0079] Specifically, the specific steps of comparing the first air pressure value with the first air pressure preset value, the second air pressure value with the second air pressure preset value, and the pressure difference with the preset pressure difference value are as follows:

[0080] The first method includes: when the first air pressure value exceeds the first air pressure preset value, the step of closing the insulating space air intake assembly 14 by the control unit 12 specifically includes: the control unit 12 controls the insulating space air intake assembly 14 to close until the first air pressure value satisfies the first air pressure preset value or less, and then the control unit 12 controls the insulating space air intake assembly 14 to open;

[0081] The second method is to open the cargo tank space gas outlet assembly 16 by the control unit 12 when the second air pressure value exceeds the second preset air pressure value, and specifically include: the control unit 12 controls the cargo tank space gas outlet assembly 16 to open until the second air pressure value satisfies the second preset air pressure value, and then the control unit 12 controls the cargo tank space gas outlet assembly 16 to close;

[0082] The third type is that when the pressure difference between the first air pressure value and the second air pressure value exceeds the preset pressure difference value, the steps of controlling the insulating space air intake component 14 to close and controlling the liquid cargo tank air intake component 15 to start by the control unit 12 specifically include: the control unit 12 controls the insulating space air intake component 14 to close and controls the liquid cargo tank air intake component 15 to start until the pressure difference between the first air pressure value and the second air pressure value is less than or equal to the preset pressure difference value, and the control unit 12 controls the insulating space air intake component 14 to open and controls the liquid cargo tank air intake component 15 to close.

[0083] The fourth method is preferred, and the above three methods are implemented simultaneously.

[0084] In this way, the insulating space air inlet assembly 14 is closed until the first air pressure value is less than or equal to the first air pressure preset value. The control unit 12 controls the insulating space air inlet assembly 14 to open, ensuring that the first inert shielding gas is supplied as soon as the air pressure value of the insulating space 6 reaches the first air pressure preset value, thereby preventing the concentration of the first inert shielding gas in the inert environment from being too low. The cargo tank space air outlet assembly 16 is opened until the second air pressure value is less than or equal to the second air pressure preset value. The control unit 12 controls the cargo tank space air outlet assembly 16 to close, ensuring that excess gas in the cargo tank space 7 is promptly closed after discharge, thereby preventing excessive discharge of the second inert shielding gas in the cargo tank space 7 from causing excessive low air pressure and gas waste. When the pressure difference between the first air pressure value and the second air pressure value is less than or equal to the preset pressure difference value, the control unit 12 controls the insulating space air inlet assembly 14 to open and controls the cargo tank space air inlet assembly 15 to close, thereby preventing excessive gas supply to the insulating space 6 or the cargo tank space 7 from disrupting the air pressure balance.

[0085] In this embodiment, during the step of determining whether the pressure difference between the first and second air pressure values ​​exceeds a preset pressure difference value, the pressure difference between the first and second air pressure values ​​is obtained by the pressure difference sensor 13. The pressure difference sensor 13 can monitor the air pressure difference and provide data support to ensure the normal operation of the air pressure control device 3.

[0086] Specifically, the control methods of the air pressure safety valves in the insulating space and the air pressure safety valves in the cargo tank space include the following three methods:

[0087] The first method is to determine whether the first air pressure value exceeds the first air pressure preset value; if so, in the step of closing the insulating space air inlet component 14 by the control unit 12, the insulating space air pressure safety valve is set to the first safety air pressure preset value. If the first air pressure value is greater than the first safety air pressure preset value after the control unit 12 closes the insulating space air inlet component 14, the insulating space air pressure safety valve automatically opens to ensure that the insulating space 6 does not overpressure;

[0088] The second method is to determine whether the second air pressure value exceeds the second air pressure preset value; if so, in the step of opening the liquid cargo tank space air outlet component 16 by the control unit 12, the liquid cargo tank space air pressure safety valve is set to the second safety air pressure preset value, and if the second air pressure value is greater than the second safety air pressure preset value after the control unit 12 opens the liquid cargo tank space air outlet component 16, the liquid cargo tank space air pressure safety valve is opened to ensure that the liquid cargo tank space 7 will not be overpressurized.

[0089] The third method is preferred, and the above two methods are implemented simultaneously.

[0090] Thus, if the air pressure in the insulating space 6 exceeds the first preset safety pressure value, it may be due to a fault in the insulating space air inlet assembly 14. The first safety protection device 17 is activated to prevent air from being supplied to the insulating space 6, thereby preventing the air pressure in the insulating space 6 from continuing to rise and restoring equilibrium after excess gas overflows from the balancing hole 8. If the air pressure in the cargo tank space 7 exceeds the second preset safety pressure value, it may be due to a fault in the cargo tank space air outlet assembly 16. The second safety protection device 18 is activated to ensure that the gas in the cargo tank space 7 is discharged in a timely manner, thereby preventing the air pressure in the cargo tank space 7 from continuing to rise and restoring equilibrium after excess gas is discharged from the second safety protection pipe.

[0091] Specifically, when the liquid cargo tank is filled for the first time, the gas in the insulating space 6 is first dried and inerted, the insulating space air inlet assembly 14 is opened to introduce nitrogen from the air inlet hole 9, and the air in the insulating space 6 is discharged from the balance pipe.

[0092] The beneficial effect of the present invention is that it can utilize the existing nitrogen system on board to provide the requirements for environmental pressure suitable for different application scenarios, ensure the inert environment of the insulating space 6 and the liquid cargo tank space 7 and the safety of the operators, and have the function of precise control of environmental pressure, with a high degree of automation, avoiding the risks caused by human operating errors. At the same time, it can also monitor the flammable gas composition in the environment in real time and alarm. When the liquid cargo tank 5 needs to be inspected and aerated, the liquid cargo tank space 7 can be aerated simply and quickly by replacing the inert protective gas introduced with air. The present invention is applicable to dual-fuel ships with liquid cargo tanks as fuel tanks, and can also be applicable to gas transport ships with liquid cargo tanks as cargo holds.

[0093] Although specific embodiments of the present invention have been described above, those skilled in the art will appreciate that these are merely illustrative and that the scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, and such changes and modifications are intended to fall within the scope of the present invention.

Claims

1. A ship, characterized in that: The vessel comprises a liquid cargo tank containment system, a compartment for storing the liquid cargo tank containment system, and an air pressure control device; The cargo tank containment system includes an insulation layer and a cargo tank, wherein the insulation layer wraps the cargo tank, an insulation space is formed between the insulation layer and the cargo tank, and the insulation space is filled with a first inert protective gas; an outer side of the insulation layer and an inner side of the compartment form a cargo tank space, and the cargo tank space is filled with a second inert protective gas; a first gas pressure in the insulation space is greater than a second gas pressure in the cargo tank space; The insulating layer is provided with a balancing hole, and both ends of the balancing hole are respectively connected to the insulating space and the liquid cargo tank space; The air pressure control device includes a first air pressure sensor, a second air pressure sensor, a control unit, an insulating space air inlet assembly, a liquid cargo tank space air inlet assembly, and a liquid cargo tank space air outlet assembly; the insulating space air inlet assembly is in a normally open state, and the liquid cargo tank space air inlet assembly and the liquid cargo tank space air outlet assembly are in a normally closed state; the insulating space air inlet assembly is used to replenish the first inert protective gas into the insulating space, the liquid cargo tank space air inlet assembly is used to replenish the second inert protective gas into the liquid cargo tank space, and the liquid cargo tank space air outlet assembly is used to discharge the second inert protective gas in the liquid cargo tank space to the outside of the cabin; The first air pressure sensor is used to detect a first air pressure value in the insulating space and transmit the detection data to the control unit, and the second air pressure sensor is used to detect a second air pressure value in the cargo tank space and transmit the detection data to the control unit; the control unit is configured to control the opening or closing of the insulating space air inlet assembly, the cargo tank space air inlet assembly, and the cargo tank space air outlet assembly according to the first and second air pressure values ​​received; When the first air pressure value is greater than the first air pressure preset value, the control unit is used to control the insulation space air intake assembly to close; when the second air pressure value is greater than the second air pressure preset value, the control unit is used to control the liquid cargo tank air outlet assembly to start; when the pressure difference between the first air pressure value and the second air pressure value exceeds the preset pressure difference value, the control unit is used to control the insulation space air intake assembly to close and control the liquid cargo tank air intake assembly to start.

2. The vessel according to claim 1, wherein: The insulating layer is further provided with an air inlet hole, and both ends of the air inlet hole are respectively connected to the insulating space and the liquid cargo tank space; The insulating space air intake assembly includes a first air source component, an insulating space air intake pipe, and an insulating space air intake valve, wherein the first air source component is in communication with the insulating space air intake pipe, the insulating space air intake pipe is connected to the air intake hole, and the insulating space air intake valve is provided on the insulating space air intake pipe and is electrically connected to the control unit; The cargo tank space air intake assembly includes a second air source component, a cargo tank space air intake pipe, and a cargo tank space air intake valve, wherein the second air source component is in communication with the insulating space air intake pipe, the cargo tank space air intake pipe is connected to the cabin, and the cargo tank space air intake valve is provided on the cargo tank space air intake pipe and is electrically connected to the control unit; The cargo tank space gas outlet assembly includes a cargo tank space gas outlet pipe and a cargo tank space gas outlet valve. Both ends of the cargo tank space gas outlet pipe are connected to the interior of the cabin and the exterior of the cabin respectively. The cargo tank space gas outlet valve is provided on the cargo tank space gas outlet pipe and is electrically connected to the control unit.

3. The vessel according to claim 2, wherein: The balancing hole is provided at the upper portion of the insulating layer, and the air inlet hole is provided at the bottom portion of the insulating layer; The first air pressure sensor is arranged in the air intake duct of the insulating space; And / or, the second air pressure sensor is arranged in the air inlet pipe of the liquid cargo tank space.

4. The ship according to claim 2, characterized in that The air pressure control device also includes a first safety protection device, which includes an insulating space air pressure safety valve and a first safety protection pipe. The two ends of the insulating space air pressure safety valve are respectively connected to the insulating space air inlet pipe and the first safety protection pipe, and the other end of the first safety protection pipe is connected to the outside of the cabin. The insulating space air pressure safety valve is set to a first safety air pressure preset value. When the first air pressure value is greater than the first safety air pressure preset value, the insulating space air pressure safety valve automatically opens. And / or, the air pressure control device further includes a second safety protection device, which includes an air pressure safety valve in the liquid cargo tank space and a second safety protection pipe, wherein both ends of the air pressure safety valve in the liquid cargo tank space are respectively connected to the liquid cargo tank space and the second safety protection pipe, and the other end of the second safety protection pipe is connected to the outside of the cabin; the air pressure safety valve in the liquid cargo tank space is set to a second safety air pressure preset value, and when the second air pressure value is greater than the second safety air pressure preset value, the air pressure safety valve in the liquid cargo tank space automatically opens.

5. The ship according to claim 4, characterized in that The air pressure control device also includes a pressure difference sensor, and the first air pressure sensor and the second air pressure sensor are both electrically connected to the pressure difference sensor. The pressure difference sensor is used to detect the pressure difference between the first air pressure value and the second air pressure value and transmit the detection data to the control unit.

6. The ship according to claim 1, characterized in that The ship also includes a gas detection device and an alarm. The detection end of the gas detection device is arranged close to the balancing hole. The gas detection device is electrically connected to the alarm. The gas detection device is used to detect combustible gas at the balancing hole.

7. A method for controlling gas pressure in a liquid cargo tank, characterized in that: The cargo tank air pressure control method is applied to the ship according to claim 5, and the cargo tank air pressure control method comprises: detecting a first air pressure value in the insulating space using the first air pressure sensor, and detecting a second air pressure value in the cargo tank space using the second air pressure sensor; Determine whether the first air pressure value exceeds the first air pressure preset value; if so, close the insulating space air intake component through the control unit; if not, keep the insulating space air intake component normally open; determining whether the second air pressure value exceeds the second air pressure preset value; if so, opening the cargo tank air outlet component by the control unit; if not, keeping the cargo tank air outlet component normally closed; Determine whether the pressure difference between the first air pressure value and the second air pressure value exceeds the preset pressure difference value; if so, control the insulating space air intake assembly to be closed and control the liquid cargo tank air intake assembly to be started by the control unit; if not, keep the insulating space air intake assembly normally open and keep the liquid cargo tank air intake assembly normally closed.

8. The method for controlling gas pressure in a liquid cargo tank according to claim 7, wherein: When the first air pressure value exceeds the first air pressure preset value, the step of closing the insulating space air intake component by the control unit specifically includes: The control unit controls the insulating space air intake assembly to be closed until the first air pressure value is less than or equal to the first air pressure preset value, and then controls the insulating space air intake assembly to be opened; And / or, when the second air pressure value exceeds the second preset air pressure value, the step of opening the cargo tank space air outlet component by the control unit specifically includes: controlling the cargo tank space air outlet component to be opened by the control unit until the second air pressure value satisfies or is less than or equal to the second preset air pressure value, and then controlling the cargo tank space air outlet component to be closed by the control unit; And / or, when the pressure difference between the first air pressure value and the second air pressure value exceeds the preset pressure difference value, the step of controlling the insulating space air intake assembly to close and controlling the liquid cargo tank air intake assembly to start by the control unit specifically includes: the control unit controls the insulating space air intake assembly to close and controls the liquid cargo tank air intake assembly to start until the pressure difference between the first air pressure value and the second air pressure value is less than or equal to the preset pressure difference value, and the control unit controls the insulating space air intake assembly to open and controls the liquid cargo tank air intake assembly to close.

9. The method for controlling gas pressure in a liquid cargo tank according to claim 7, wherein: In the step of determining whether the pressure difference between the first air pressure value and the second air pressure value exceeds the preset pressure difference value, the pressure difference between the first air pressure value and the second air pressure value is acquired by a pressure difference sensor.

10. The method for controlling gas pressure in a liquid cargo tank according to claim 7, wherein: In the step of determining whether the first air pressure value exceeds the first air pressure preset value; if so, in closing the insulating space air intake assembly by the control unit, the insulating space air pressure safety valve is set to a first safety air pressure preset value, and if the first air pressure value is greater than the first safety air pressure preset value after the control unit closes the insulating space air intake assembly, the insulating space air pressure safety valve is automatically opened until the first air pressure value satisfies a condition that the first air pressure value is less than or equal to the first safety air pressure preset value; and / or, in determining whether the second air pressure value exceeds the second preset air pressure value; if so, in the step of opening the cargo tank space gas outlet assembly by the control unit, the cargo tank space air pressure safety valve is set to the second preset safety air pressure value; if, after the control unit opens the cargo tank space gas outlet assembly, the second air pressure value is greater than the second preset safety air pressure value, the cargo tank space air pressure safety valve is opened until the second air pressure value satisfies a condition that the second air pressure value is less than or equal to the second preset safety air pressure value.

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