Cargo aircraft ventilation system and cargo aircraft ventilation method

Abstract

The present invention relates to a ventilation system for a cargo aircraft, which is used to control the ventilation of a main cargo hold and a cockpit of the cargo aircraft, and includes: a mixing chamber, which receives gas from a refrigeration assembly; an exhaust valve, through which exhaust gas from the main cargo hold and the cockpit is discharged to the outside of the aircraft; a first passage for ventilating the main cargo hold, wherein the first passage is provided with a first shutoff valve between a gas outlet of the mixing chamber and a gas inlet of the main cargo hold; a second passage for ventilating the cockpit; and a third passage, wherein the third passage fluid connects the gas outlet of the mixing chamber and the exhaust valve; wherein a second shutoff valve is provided between the gas outlet of the mixing chamber and the exhaust valve. Through this ventilation system, the ventilation of the main cargo hold can be controlled separately without affecting the normal ventilation of the cockpit, and the mixing chamber can be ensured not to be over-pressurized, thereby ensuring the safety of the cargo aircraft. In addition, the present invention also relates to a ventilation method for cargo aircraft.

Description

Technical Field

[0001] The invention belongs to the field of civil aviation and relates to a ventilation system for a cargo aircraft. In addition, the invention also relates to a ventilation method for a cargo aircraft. Background Art

[0002] The main cargo hold of an all-cargo aircraft is defined as a Class E cargo hold (i.e., a cargo hold on an aircraft used only for loading cargo). According to CCAR25.857 (e), a Class E cargo hold should have measures to cut off the ventilation airflow entering or within the cargo hold, and the controls of these measures should be accessible to the flight crew in the crew compartment.

[0003] The main cargo hold of cargo aircraft with E-class cargo holds is not designed and installed with an active fire extinguishing system (such as spraying fire extinguishing agents, etc.), and personnel are not allowed to enter the main cargo hold during flight. When a smoke alarm appears in the main cargo hold during flight, the corresponding smoke alarm light will light up. After the crew detects smoke in the cargo hold, they will cut off the ventilation of the main cargo hold, thereby limiting the oxygen supply and controlling the fire to achieve the purpose of extinguishing the fire. Some models will also cut off the cockpit ventilation. At this time, in order to ensure the safe air / oxygen supply to the crew in the cockpit, the aircraft will descend below a certain altitude (for example, below 10,000 feet) to provide a sufficient concentration of oxygen. This will reduce flight safety, increase fuel consumption, and may extend cargo transportation time.

[0004] In addition, in the prior art, since the mixing chamber of the air conditioning system is usually made of composite materials, if the ventilation of the main cargo compartment is cut off, the air from the refrigeration assembly will gather in the mixing chamber, causing an overpressure problem. In particular, when the ventilation of the cockpit is cut off, the excessive pressure in the mixing chamber may damage the ventilation pipeline, causing safety hazards and reducing system reliability.

[0005] Therefore, in order to avoid damage to the ventilation duct due to excessive pressure in the mixing chamber, it is urgent to propose a ventilation system that meets the provisions of CCAR25.857 (e), is suitable for use in the fire extinguishing state of the main cargo compartment of cargo aircraft, and has high reliability. This cargo aircraft ventilation system can overcome one or more shortcomings existing in the prior art. Summary of the invention

[0006] In order to ensure the normal operation of the ventilation system and improve the safety design margin of the ventilation system, the present invention proposes a ventilation system for cargo aircraft to overcome one or more of the above-mentioned shortcomings of the cargo aircraft design in the prior art, especially to overcome the technical problem of low reliability of the mixing chamber existing in the fire extinguishing ventilation structure of the main cargo compartment of the cargo aircraft.

[0007] According to one aspect of the present invention, a ventilation system for a cargo aircraft is provided, which can be used to control the ventilation of a main cargo compartment and a cockpit of a cargo aircraft, and can include:

[0008] a mixing chamber, the mixing chamber receiving gas from the refrigeration assembly;

[0009] Exhaust valve, exhaust from the main cargo compartment and cockpit is discharged outside the aircraft through the exhaust valve;

[0010] a first passage, the first passage fluidly connecting the gas outlet of the mixing chamber and the gas inlet of the main cargo hold, and fluidly connecting the gas outlet of the main cargo hold and the exhaust valve, wherein a first shut-off valve is provided between the gas outlet of the mixing chamber and the gas inlet of the main cargo hold;

[0011] A second passage fluidly connects the gas outlet of the mixing chamber and the gas inlet of the cockpit, and fluidly connects the gas outlet of the cockpit and the exhaust valve; and

[0012] A third passage, the third passage fluid is connected to the gas outlet of the mixing chamber and the exhaust valve;

[0013] In this case, a second shut-off valve is arranged between the gas outlet of the mixing chamber and the exhaust valve.

[0014] Through this ventilation system, the ventilation of the main cargo hold can be controlled separately, so that when the main cargo hold catches fire, the ventilation of the main cargo hold can be shut off separately, so that the fire in the main cargo hold can be controlled due to lack of oxygen without affecting the normal ventilation of the cockpit. In addition, through the third passage and the second shut-off valve, it can be ensured that the pressure in the mixing chamber will not be too high due to shutting off the ventilation of the main cargo hold, thereby ensuring that there will be no air leakage due to the explosion of the mixing chamber, and meeting the requirements of CCAR25.857 (e) E-class cargo hold.

[0015] According to the above aspects of the present invention, preferably, the cargo aircraft ventilation system may further include an exhaust check valve, which is arranged in parallel with the second shut-off valve between the gas outlet of the mixing chamber and the exhaust valve.

[0016] With this arrangement, when the second shut-off valve fails due to a fire or other reasons, resulting in the mixing chamber being unable to release pressure / exhaust air normally through the third passage and the second shut-off valve, the exhaust one-way valve can be used as a backup for the second shut-off valve, so that the cargo aircraft ventilation system according to the present invention has a dual pressure relief / exhaust protection function, thereby improving the safety of the cargo aircraft.

[0017] According to the above aspects of the present invention, preferably, the exhaust check valve can be kept closed in an initial state, and when the pressure between the gas outlet of the mixing chamber and the exhaust check valve reaches a predetermined pressure threshold, the exhaust check valve can be opened.

[0018] Through this arrangement, when the pressure in the mixing chamber is too high, the exhaust one-way valve can be opened autonomously, thereby being able to adapt to various situations of increased pressure in the mixing chamber, including excessive pressure in the mixing chamber caused by a fire in the main cargo hold, thereby ensuring the safety of the cargo aircraft to the greatest extent.

[0019] According to the above aspects of the present invention, preferably, the cargo aircraft ventilation system may further include a controller, which controls the operation of the first shut-off valve and the second shut-off valve according to a predetermined control logic based on data from sensors arranged in the cargo aircraft ventilation system.

[0020] In this way, under normal circumstances, the first shut-off valve can be opened and the second shut-off valve can be kept closed. Under necessary circumstances, such as when the main cargo hold is on fire, the first shut-off valve can be closed and the second shut-off valve can be opened. This ensures that the fire in the main cargo hold is under control while ensuring normal ventilation of the cockpit, such as oxygen supply and temperature control, and that the mixing chamber does not explode.

[0021] According to another aspect of the present invention, a method for ventilation of a cargo aircraft is provided, wherein:

[0022] Under the non-fire condition, the method may include the following steps:

[0023] Allow air from the refrigeration unit to enter the mixing chamber,

[0024] The gas in the mixing chamber is made to flow through a first passage and a second passage between a gas outlet of the mixing chamber and an exhaust valve so as to be supplied to a main cargo hold and a cockpit of a cargo aircraft respectively; and

[0025] The gas is discharged outside the engine through the exhaust valve;

[0026] In the event of a fire in the main cargo hold, the method may include the following steps:

[0027] closing the first shut-off valve in the first passage to cut off the air supply to the main cargo hold; and

[0028] The second shut-off valve of the third passage is opened so that the gas in the mixing chamber is discharged outside the machine through the exhaust valve.

[0029] According to this ventilation control method, the ventilation of the main cargo hold and the cockpit can be satisfied at the same time under normal circumstances, and when the main cargo hold is on fire, as described above, the ventilation of the main cargo hold can be shut off separately, so that the fire in the main cargo hold is controlled by hypoxia without affecting the normal ventilation of the cockpit. In addition, through the third passage and the second shut-off valve, it can be ensured that the pressure in the mixing chamber will not be too high due to shutting off the ventilation of the main cargo hold, thereby protecting the mixing chamber from explosion, and meeting the requirements of CCAR25.857 (e) E-class cargo hold.

[0030] According to the above aspect of the present invention, preferably, when the second shut-off valve fails, the method may further include the following steps:

[0031] When the pressure of the gas in the mixing chamber reaches a predetermined pressure threshold, the exhaust one-way valve in the third passage, which is arranged in parallel with the second shut-off valve, is opened.

[0032] Through this method, when the second shut-off valve fails, for example, when the second shut-off valve fails due to a fire in the main cargo hold, the mixing chamber will not be able to normally relieve pressure / exhaust air through the third passage. By opening the exhaust one-way valve arranged in parallel with the second shut-off valve, the safety of the mixing chamber and the cargo aircraft can be improved, for example, the mixing chamber will not explode.

[0033] Therefore, the cargo aircraft ventilation system of the present invention can meet the use requirements, overcome the shortcomings of the prior art and achieve the predetermined purpose. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to further clearly describe the ventilation system for cargo aircraft according to the present invention, the present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments. In the accompanying drawings:

[0035] Figure 1 is a schematic diagram of a cargo aircraft ventilation system according to a non-limiting embodiment of the present invention.

[0036] The above drawings are merely schematic and are not drawn strictly to scale.

[0037] List of reference numerals in the figures and embodiments:

[0038] 100 - Ventilation systems for cargo aircraft, including;

[0039] 10 - mixing chamber;

[0040] 20 - exhaust valve;

[0041] 30 - First access, including;

[0042] 31 - first shut-off valve;

[0043] 40 - Second access;

[0044] 50 - Third access, including;

[0045] 51 - second shut-off valve;

[0046] 52 - exhaust check valve;

[0047] 60 - controller;

[0048] 200 - cargo aircraft, including;

[0049] 201 - Main cargo hold;

[0050] 202 - Cockpit. DETAILED DESCRIPTION

[0051] It should be understood that, unless expressly stated otherwise, the present invention may adopt various alternative orientations and step sequences. It should also be understood that the specific devices shown in the drawings and described in the specification are merely exemplary embodiments of the inventive concepts disclosed and defined herein. Therefore, unless otherwise expressly stated, the specific orientations, directions or other physical characteristics of the various embodiments disclosed should not be considered as limiting.

[0052] According to CCAR-25R4 airworthiness standards for transport category airplanes, the following provisions are made in Section 25.857 Cargo Compartment Classification:

[0053] (e) Class E A Class E cargo hold is a cargo hold on an aircraft used only for loading cargo:

[0054] (1) (spare)

[0055] (2) An approved, independent smoke or fire detector system that provides a warning at the pilot or flight engineer's workstation;

[0056] (3) There are means to shut off the ventilation flow into or within the cargo compartment, and the controls of these means are accessible to the flight crew in the crew compartment.

[0057] When a cargo aircraft has a smoke alarm in the main cargo hold during flight, the corresponding smoke alarm light will light up. After the crew detects the smoke in the cargo hold, they will cut off the ventilation of the main cargo hold in accordance with the requirements of CCAR25.857 (e) E, thereby limiting the oxygen supply and controlling the fire to achieve the purpose of extinguishing the fire. Some models will also cut off the cockpit ventilation at the same time.

[0058] Figure 1 is a schematic diagram of a cargo aircraft ventilation system 100 according to a non-limiting embodiment of the present invention.

[0059] The cargo aircraft ventilation system (or air conditioning system) 100 can be used to control the ventilation of the main cargo hold 201 and the cockpit 202 of the cargo aircraft 200, so as to ensure, for example, on the one hand, that the cargo in the main cargo hold 201 is kept under appropriate temperature and pressure conditions, and on the other hand, to ensure the environmental comfort of the cockpit 202 and any escort cabin, thereby ensuring the flight comfort of relevant personnel such as escort personnel, pilots and mechanics.

[0060] Generally, various sensors may be provided in the main cargo hold 201 and the cockpit 202 to monitor the temperature, pressure, etc. in the main cargo hold 201 and the cockpit 202. In particular, a smoke sensor or a pyrotechnic (fire alarm) sensor may be provided in the main cargo hold 201 to detect whether a fire or the like occurs in the main cargo hold 201.

[0061] like Figure 1 As shown, the ventilation system 100 for a cargo aircraft may mainly include: a mixing chamber 10 and an exhaust valve 20, and a plurality of fluid passages connected between the mixing chamber 10 and the exhaust valve 20, such as the three fluid passages shown in the figure.

[0062] As a non-limiting example, the mixing chamber 10 may be the most upstream component of the cargo aircraft ventilation system 100, which is used to receive gas from a refrigeration assembly, for example, respectively receive gas from a first refrigeration assembly and a second refrigeration assembly, so that the gas is fully mixed in the mixing chamber to obtain gas with a desired temperature and pressure. Then, the mixed gas may be supplied to the main cargo compartment 201 and the cockpit 202 of the cargo aircraft 200 and a possible escort compartment via one or more fluid passages to adjust the temperature and / or pressure in these compartments.

[0063] Typically, in a cargo aircraft ventilation system 100 of a cargo aircraft, the mixing chamber 10 may be made of a composite material. In addition, preferably, the mixing chamber 10 may be provided with a temperature sensor, a pressure sensor, etc., to monitor the temperature and pressure in the mixing chamber.

[0064] The exhaust valve 20 may be the most downstream component of the ventilation system 100 of the cargo aircraft, and the exhaust gas from the main cargo hold 201 and the cockpit 202 is discharged outside the cargo aircraft via the exhaust valve 20 and corresponding coordinated fluid pipelines.

[0065] As a non-limiting example, the three fluid passages of the cargo aircraft ventilation system 100 may include: a first passage 30 , a second passage 40 , and a third passage 50 .

[0066] A portion of the first passage 30 can fluidly connect the gas outlet of the mixing chamber 10 and the gas inlet of the main cargo compartment 201, so that the mixed gas from the refrigeration assembly enters the main cargo compartment 201. Another portion of the first passage 30 can fluidly connect the gas outlet of the main cargo compartment 201 and the gas inlet of the exhaust valve 20, so that the gas exhausted from the main cargo compartment 201 is exhausted to the outside of the fuselage of the cargo aircraft via the exhaust valve 20 and the corresponding fluid pipeline.

[0067] In the preferred embodiment shown in the drawings, a main cargo hold ventilation shutoff valve, such as a first shutoff valve 31, may be provided between the gas outlet of the mixing chamber 10 and the gas inlet of the main cargo hold 201. The main cargo hold ventilation shutoff valve may be used to independently control the connection and disconnection of the first passage 30 so as to control the ventilation of the main cargo hold 201, so that in an emergency, such as when smoke or fire occurs in the main cargo hold 201, the ventilation of the main cargo hold 201 is actively cut off, so that combustion is suspended or terminated due to lack of oxygen.

[0068] A portion of the second passage 40 can be fluidly connected to the gas outlet of the mixing chamber 10 and the gas inlet of the cockpit 202 (including the escort cabin), so that the mixed gas from the refrigeration assembly enters the cockpit 202. Another portion of the second passage 40 can be fluidly connected to the gas outlet of the cockpit 202 and the gas inlet of the exhaust valve 20, so that the gas exhausted from the cockpit 202 is discharged to the outside of the fuselage of the cargo aircraft via the exhaust valve 20 and the related fluid pipelines.

[0069] The third passage 50 can fluidly connect the gas outlet of the mixing chamber 10 and the gas inlet of the exhaust valve 20. In the flow path of the third passage 50, a second shutoff valve 51 can be provided between the gas outlet of the mixing chamber 10 and the exhaust valve 20 to control the connection or disconnection of the fluid connection between the mixing chamber 10 and the exhaust valve 20.

[0070] The first passage 30 , the second passage 40 , and the third passage 50 may be made of any ventilation duct material known in the art, such as various metals or alloys thereof, and various polymer materials.

[0071] The cargo aircraft ventilation system 100 may further include an additional main cargo compartment exhaust check valve. For example, in the preferred embodiment shown in the drawings, the cargo aircraft ventilation system 100 further includes an exhaust check valve 52, which may be arranged in parallel with the second shut-off valve 51, for example, between the gas outlet of the mixing chamber 10 and the exhaust valve 20.

[0072] Preferably, the exhaust check valve 52 can remain closed in the initial state, and when the pressure between the gas outlet of the mixing chamber 10 and the exhaust check valve 52 reaches a predetermined pressure threshold, the exhaust check valve 52 can be opened to release the pressure accumulated therein.

[0073] In addition, preferably, in order to improve or enhance the ventilation / aeration effect, corresponding pumping devices (not shown in the drawings) can be respectively provided in the three fluid passages, and various sensors such as pressure sensors can also be provided to monitor the pressure in the fluid passages, such as air pressure, etc.

[0074] As a non-limiting embodiment, the cargo aircraft ventilation system 100 may further include a controller 60, which may control the operation of the first shut-off valve 31 and the second shut-off valve 51 according to a predetermined control logic based on data from sensors disposed in the cargo aircraft ventilation system 100 (e.g., a pressure sensor in the mixing chamber 10).

[0075] The controller 60 may be embodied as an application specific integrated circuit chip and / or some other type of very highly integrated circuit chip. Alternatively, the controller 60 may take the form of a microprocessor or discrete electrical and electronic components. Or the controller 60 may be a main controller or a portion thereof on a cargo aircraft, for example, disposed in the cockpit 202 of the cargo aircraft.

[0076] As a non-limiting example, when smoke or fire occurs in the main cargo hold 201, the controller 60 can control the first shut-off valve 31 to interrupt the fluid connection between the mixing chamber 10 and the main cargo hold 201 based on an alarm instruction issued by the smoke sensor (or fire sensor) in the main cargo hold 201, thereby extinguishing the fire point in the main cargo hold 201 due to lack of oxygen.

[0077] Preferably, the controller 60 may include a memory, and the memory may include a non-transitory storage medium that electronically stores information. The memory may include one or more of an optically readable storage medium, a charge-based storage medium (e.g., EEPROM, RAM, etc.), a solid-state storage medium (e.g., a flash drive, etc.), and / or other electronically readable storage medium. The electronic memory may store control algorithms, information determined by a processor, information received from a sensor, or other information that implements the functions described herein. For example, the control algorithm may include a corresponding algorithm for controlling the opening or closing of the first shutoff valve 31, the second shutoff valve 51, and the exhaust check valve 52.

[0078] As a non-limiting example, the cargo aircraft ventilation method according to the present invention may optionally include the following steps:

[0079] For example, in the absence of a fire, in order to achieve ventilation, pressure or temperature regulation of the main cargo hold 201 and the cockpit 202, the method may include:

[0080] First, air from the refrigeration assembly may be admitted into the mixing chamber 10 where it may be mixed to achieve a desired output air flow, pressure, and temperature.

[0081] Next, the gas in the mixing chamber 10 can flow through the first passage 30 and the second passage 40 between the gas outlet of the mixing chamber 10 and the gas inlet of the exhaust valve 20 so as to be supplied to the main cargo hold 201 and the cockpit 202 of the cargo aircraft 200 respectively.

[0082] The gas flowing through the main cargo hold 201 and the cockpit 202 is then discharged outside the fuselage of the cargo aircraft through the gas outlet of the exhaust valve 20 and the corresponding fluid pipeline, thereby achieving the desired ventilation / air conditioning to maintain the temperature, pressure and / or air quality in the main cargo hold 201 and the cockpit 202 at the desired level.

[0083] As a non-limiting example, when the main cargo hold 201 is on fire, for example, when the main cargo hold smoke alarm is triggered, the corresponding smoke alarm light is turned on, and after the crew detects the cargo hold smoke alarm, the ventilation of the main cargo hold 201 is cut off, for example, via the controller 60. Specifically, the first shut-off valve 31 in the first passage 30 may be closed first to cut off the air supply to the main cargo hold 201.

[0084] In this way, when the main cargo hold 201 is on fire, the main cargo hold ventilation shut-off valve is cut off, for example, the first shut-off valve 31 is cut off, but the ventilation function of the cockpit 202 through the second passage 40 is not cut off, thereby ensuring the comfort of the cargo aircraft pilots and escorts in the cockpit 202.

[0085] At this time, that is, when the main cargo hold 201 is on fire (when the main cargo hold ventilation shut-off valve is closed), in order to prevent air from the refrigeration assembly from accumulating in the mixing chamber 10, excess air in the mixing chamber 10 needs to be discharged out of the machine to prevent damage to the mixing chamber 10 or the ventilation pipeline due to excessive pressure in the mixing chamber 10. The second shut-off valve 51 arranged in the third passage 50 can be opened to allow excess gas in the mixing chamber 10 to be discharged out of the machine through the exhaust valve 20 and the corresponding exhaust pipeline.

[0086] When the main cargo hold exhaust shut-off valve fails, for example, when the second shut-off valve 51 fails due to a fire in the main cargo hold 201, the mixing chamber 10 will not be able to smoothly discharge excess gas, so that the pressure of the gas in the mixing chamber 10 will increase, and when the pressure reaches a predetermined pressure threshold, the exhaust check valve 52 in the third passage 50 arranged in parallel with the second shut-off valve 51 can be opened. This ensures the normal operation of the ventilation system and improves the safety design margin of the ventilation system. In other words, when the ventilation of the main cargo hold 201 is cut off, the mixing chamber 10 of the cargo aircraft ventilation system 100 has a dual pressure relief protection function.

[0087] The exhaust one-way valve 52 can be regarded as a backup of the second shut-off valve 51 , and therefore, it is preferably arranged away from the second shut-off valve 51 , or arranged in an environment different from that of the second shut-off valve 51 .

[0088] The cargo aircraft ventilation system 100 according to the present invention can be applied to new models of cargo aircraft, so as to realize separate ventilation of the main cargo compartment 201 and the cockpit 202, and at the same time improve the reliability of the mixing chamber 10 during fire extinguishing of the cargo aircraft, especially to enable the mixing chamber 10 to have a dual pressure relief protection function, thereby improving the market competitiveness of cargo aircraft equipped with the cargo aircraft ventilation system 100 according to the present invention.

[0089] As used herein, the terms "upstream", "downstream" to indicate position or orientation, and the terms "first", "second", etc. to indicate order are intended only to enable those of ordinary skill in the art to better understand the concept of the present invention as shown in the form of a preferred embodiment, and are not intended to limit the present invention. Unless otherwise specified, all orders, positions, or orientations are only used for the purpose of distinguishing one element / component / structure from another element / component / structure, and unless otherwise specified, do not represent any particular order, sequence of operations, direction, or orientation. For example, in an alternative embodiment, the "first refrigeration assembly" may be the "second refrigeration assembly", and the "first passage" may alternatively refer to the "second passage".

[0090] In summary, the cargo aircraft ventilation system 100 according to the embodiment of the present invention overcomes the shortcomings of the prior art and achieves the intended purpose of the invention.

[0091] Although the above description of the cargo aircraft ventilation system of the present invention is combined with the preferred embodiments, it should be recognized by those skilled in the art that the above examples are only for illustration and cannot be used as limitations of the present invention. Therefore, various modifications and variations can be made to the present invention within the spirit of the claims, and these modifications and variations will fall within the scope required by the claims of the present invention.

Claims

1. A cargo aircraft ventilation system (100), the cargo aircraft ventilation system being used to control ventilation of a main cargo hold (201) and a cockpit (202) of a cargo aircraft (200), and comprising: A mixing chamber (10), the mixing chamber receiving gas from the refrigeration component so that the gas is fully mixed in the mixing chamber (10) to obtain gas with a desired temperature and pressure, and a temperature sensor and a pressure sensor are arranged in the mixing chamber (10) to monitor the temperature and pressure in the mixing chamber (10); an exhaust valve (20), through which exhaust gas from the main cargo hold (201) and the cockpit (202) is discharged outside the aircraft; a first passage (30), the first passage fluidly connecting the gas outlet of the mixing chamber (10) and the gas inlet of the main cargo hold (201), and fluidly connecting the gas outlet of the main cargo hold (201) and the exhaust valve (20), wherein a first shut-off valve (31) is provided between the gas outlet of the mixing chamber (10) and the gas inlet of the main cargo hold (201); a second passage (40) fluidically connecting the gas outlet of the mixing chamber (10) and the gas inlet of the cockpit (202), and fluidly connecting the gas outlet of the cockpit (202) and the exhaust valve (20); and A third passage (50), wherein the third passage fluidly connects the gas outlet of the mixing chamber (10) and the exhaust valve (20); A second shutoff valve (51) and an exhaust check valve (52) are provided between the gas outlet of the mixing chamber (10) and the exhaust valve (20); the exhaust check valve and the second shutoff valve (51) are arranged in parallel between the gas outlet of the mixing chamber (10) and the exhaust valve (20).

2. The cargo aircraft ventilation system (100) according to claim 1, characterized in that: The exhaust check valve (52) remains closed in an initial state, and when the pressure between the gas outlet of the mixing chamber (10) and the exhaust check valve (52) reaches a predetermined pressure threshold, the exhaust check valve (52) opens.

3. The cargo aircraft ventilation system (100) according to any one of claims 1-2, characterized in that: The cargo aircraft ventilation system further comprises a controller (60) which controls the operation of the first shutoff valve (31) and the second shutoff valve (51) according to a predetermined control logic based on data from a sensor provided in the cargo aircraft ventilation system (100).

4. A method for ventilation of a cargo aircraft, characterized in that: 1) Under the non-fire condition, the method comprises the following steps: Allowing air from a refrigeration component to enter a mixing chamber (10) so that the gas is fully mixed in the mixing chamber (10) to obtain gas having a desired temperature and pressure, and providing a temperature sensor and a pressure sensor in the mixing chamber (10) to monitor the temperature and pressure in the mixing chamber (10); The gas in the mixing chamber (10) is caused to flow through a first passage (30) and a second passage (40) between a gas outlet of the mixing chamber (10) and an exhaust valve (20) so as to be supplied to a main cargo hold (201) and a cockpit (202) of a cargo aircraft (200), respectively; and Discharging the gas outside the machine through the exhaust valve (20); 2) When the main cargo hold (201) is on fire, the method comprises the following steps: closing the first shut-off valve (31) in the first passage (30) to cut off the air supply to the main cargo hold (201); and Opening the second shutoff valve (51) of the third passage (50) so that the gas in the mixing chamber (10) is discharged outside the machine through the exhaust valve (20); 3) When the second shut-off valve (51) fails, the method further comprises the following steps: When the pressure of the gas in the mixing chamber (10) reaches a predetermined pressure threshold, the exhaust one-way valve (52) in the third passage (50) arranged in parallel with the second shut-off valve (51) is opened.

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