Lower cargo hold fire alarm method, cargo hold fire detection system and fire detector
By adopting a composite fire detector and specific alarm logic in the lower cargo hold fire detection system, the problem of high false alarm rate in the lower cargo hold fire detection system is solved, and the accuracy and response speed of fire alarms are improved.
Patent Information
- Application Number
- CN202510161920.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-13
- Publication Date
- 2025-05-13
Smart Images
Figure CN119992736A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a lower cargo hold fire alarm method, and also to a cargo hold fire detection system and a fire detector. The present invention belongs to the technical field of aircraft alarm system design. Background Art
[0002] Some cargo aircraft have two levels, the main cargo hold and the lower cargo hold. The main cargo hold is above the lower cargo hold, and the main cargo hold has a larger volume than the lower cargo hold. In addition, when converting a passenger aircraft to a cargo aircraft, it is common to retain the original two-level stratification, namely the passenger cabin and the lower cargo hold, and convert the passenger cabin into the main cargo hold.
[0003] The main cargo hold and the lower cargo hold are equipped with independent fire detection systems, such as smoke detection systems and fire suppression or extinguishing systems. When the fire detection system detects a fire, it will trigger the cockpit alarm indication and notify the crew, who will then execute the corresponding fire suppression or extinguishing, as well as the relevant emergency procedures.
[0004] The ventilation system of a converted cargo aircraft is usually designed so that airflow enters the main cargo hold from the ceiling of the main cargo hold, then passes through the lower cargo hold triangle area and finally exits the aircraft.
[0005] When the sealing condition of the lower cargo hold triangle area and the interior wall panel of the lower cargo hold is not good, the airflow can easily enter the lower cargo hold from the lower cargo hold triangle area. In this case, once the main cargo hold is on fire, the smoke will follow the airflow from the main cargo hold into the lower cargo hold triangle area, and then penetrate into the lower cargo hold, causing the fire detection system of the lower cargo hold to give a false alarm.
[0006] In view of the problem that the fire detection system of the lower cargo hold is prone to false alarms, the fire detection alarm and disposal methods commonly used in the lower cargo hold of mainstream aircraft currently include the following three methods:
[0007] 1) Add operating procedures to AFM. Add preset operating procedures to AFM, that is, when the smoke detector in the main cargo hold sounds an alarm, inform the crew that it may cause a false alarm in the lower cargo hold and require the crew to take appropriate actions, such as sending personnel to check or directly release fire extinguishing agents.
[0008] However, in the current mainstream aircraft models, the added operating procedures in the AFM are only applicable to the situation where a false alarm occurs in the cargo hold of a cargo aircraft with a single cargo hold, and releasing the fire extinguishing agent in the case of a false alarm will cause a waste of the fire extinguishing agent.
[0009] 2) Suppress the lower cargo hold fire alarm signal. When the main cargo hold is on fire and the crew performs the fire extinguishing operation procedure, the fire protection controller of the aircraft's fire detection system suppresses the lower cargo hold fire alarm signal.
[0010] However, although the lower cargo hold fire detector has the problem of false alarms, it is still possible to give a correct alarm, and completely suppressing the lower cargo hold fire alarm signal may result in missed alarms.
[0011] 3) Suppress the lower cargo hold fire alarm signal and activate the backup sensor. As above, suppress the lower cargo hold fire alarm signal and activate the backup fire detector, which is a backup device independent of the lower cargo hold fire detector and has a fire detection function.
[0012] However, although the backup fire detectors can still alert the crew, it takes a certain amount of time to activate the backup fire detectors, which does not meet the alarm response time requirements of airworthiness requirements and may delay the fire. Summary of the invention
[0013] In view of the above problems in the prior art, the inventor provides a lower cargo hold fire alarm method and a cargo hold fire detection system to solve the problem of high false alarm rate in the lower cargo hold fire detection system in the prior art.
[0014] In a first example of the lower cargo hold fire alarm method, the lower cargo hold fire alarm method comprises: in the case that at least two lower cargo hold fire detectors are in a normal state, when at least two lower cargo hold fire detectors output fire alarm signals, the fire protection controller outputs a lower cargo hold fire alarm signal; and in the case that at least one of the at least two lower cargo hold fire detectors is in a fault state or a false alarm state, when any lower cargo hold fire detector in a normal state outputs a fire alarm signal, the fire protection controller outputs a lower cargo hold fire alarm signal, wherein, in the case that the fire protection controller has received the main cargo hold fire alarm signal, the lower cargo hold fire alarm signal is The cargo hold fire detector executes a first alarm logic to output a fire alarm signal, and wherein, in the case where no main cargo hold fire alarm signal is received, the lower cargo hold fire detector executes a second alarm logic to output a fire alarm signal, wherein the first alarm logic includes: when the first detection module and the second detection module of the lower cargo hold fire detector both output module alarm signals, the fire protection controller determines that the lower cargo hold fire detector outputs a fire alarm signal, and wherein the second alarm logic includes: when at least one of the first detection module and the second detection module outputs a module alarm signal, the lower cargo hold fire detector outputs a fire alarm signal.
[0015] In the second example of the lower cargo hold fire alarm method, the first example is optionally included, and the first alarm logic also includes: when the first detection module of the lower cargo hold fire detector and only one output module of the second detection module alarm signal, the fire protection controller determines that the lower cargo hold fire detector is in a false alarm state rather than a normal state, and isolates the lower cargo hold fire detector.
[0016] In the third example of the lower cargo hold fire alarm method, which optionally includes one or more of the first example and the second example, the first alarm logic also includes: when the fire protection controller determines that the lower cargo hold fire detector is in a false alarm state, after only one output module in the first detection module and the second detection module outputs an alarm signal and stops outputting for a predetermined time, the fire protection controller determines that the lower cargo hold fire detector returns to a normal state instead of being in a false alarm state.
[0017] In the fourth example of the lower cargo hold fire alarm method, one or more of the first to third examples are optionally included, and when the first detection module is a smoke detection module, and the second detection module is a carbon monoxide gas detection module or a temperature detection module, the first alarm logic also includes: when the first detection module is normal and the second detection module is faulty, the fire protection controller determines that the lower cargo hold fire detector is in a faulty state, and the fire protection controller does not adopt the fire alarm signal of the lower cargo hold fire detector; when the first detection module is faulty and the second detection module is normal, the fire protection controller determines that the lower cargo hold fire detector is in a normal state, and further: when the second detection module outputs a module alarm signal, the fire protection controller determines that the lower cargo hold fire detector outputs a fire alarm signal; when both the first detection module and the second detection module are faulty, the fire protection controller determines that the lower cargo hold fire detector is in a faulty state, and the fire protection controller does not adopt the fire alarm signal of the lower cargo hold fire detector.
[0018] In the fifth example of the lower cargo hold fire alarm method, which optionally includes one or more of the first to fourth examples, the second alarm logic also includes: when only one of the first detection module and the second detection module is normal, the fire protection controller determines that the lower cargo hold fire detector is in a normal state, and further: when only one of the first detection module and the second detection module is normal outputs a module alarm signal, the lower cargo hold fire detector outputs a fire alarm signal; when both the first detection module and the second detection module fail, the fire protection controller determines that the lower cargo hold fire detector is in a faulty state, and the fire protection controller does not adopt the fire alarm signal of the lower cargo hold fire detector.
[0019] A cargo hold fire detection system according to the present invention, wherein the cargo hold fire detection system comprises: a fire protection controller; a main cargo hold fire alarm unit, which provides a main cargo hold fire alarm signal when a fire occurs in the main cargo hold; and a lower cargo hold fire alarm unit, which comprises at least two lower cargo hold fire detectors, each of which comprises a first detection module and a second detection module, wherein the first detection module is a smoke detection module, and the second detection module is a carbon monoxide gas detection module or a temperature detection module.
[0020] A fire detector according to the present invention comprises: a first detection module and a second detection module, wherein the first detection module is a smoke detection module, and the second detection module is a carbon monoxide gas detection module or a temperature detection module.
[0021] For cargo aircraft, in the event of a fire in the main cargo hold, a composite fire detector is used in the lower cargo hold, and "AND" logic is used. In the event of no fire in the main cargo hold, a composite fire detector is used in the lower cargo hold, and "OR" logic is used. This can effectively reduce the probability of false alarms in the lower cargo hold due to poor sealing, and improve the alarm response speed of the smoke detection system.
[0022] The fire detector uses a composite smoke detector with a smoke detection module and a temperature detection module or a smoke detection module and a CO gas detection module, which simultaneously collects smoke and temperature or smoke and CO gas signals during a fire, effectively reducing the probability of false alarms in fire detection; BRIEF DESCRIPTION OF THE DRAWINGS
[0023] In order to describe the implementation of the above and other features of the present invention, a more particular description of the invention briefly described above will be presented with reference to the exemplary embodiments of the invention shown in the accompanying drawings. It will be understood that these drawings only depict exemplary embodiments of the invention and should not be considered as limiting the scope thereof. The invention will be described and explained through the use of the accompanying drawings and with additional features and details. In the drawings:
[0024] Figure 1 is a cross-sectional view of a cargo aircraft according to the prior art, showing a main cargo hold, a lower cargo hold, a lower cargo hold triangle, and an airflow path;
[0025] Figure 2 is a schematic diagram of a cargo hold fire detection system according to an embodiment of the present invention;
[0026] Figure 3 is a schematic diagram of the alarm logic of the lower cargo hold fire detector of the cargo hold fire detection system according to an embodiment of the present invention.
[0027] The drawings are roughly drawn to scale, however, the dimensions in the drawings are only schematic and not necessarily drawn strictly to scale, but are intended to provide a clearer description. In other embodiments, other relative dimensions may be used.
[0028] Here and throughout the following, identical features appearing in different figures are denoted by identical or similar reference numerals.
[0029] List of reference numerals:
[0030] 1 Main cargo hold
[0031] 2 Lower cargo hold
[0032] 3 Lower cargo hold triangle
[0033] 100 Fire protection controller
[0034] 200 Main cargo hold fire alarm unit
[0035] 300 Lower cargo hold fire alarm department
[0036] 310 Lower cargo hold fire detector
[0037] 311 First Detection Module
[0038] 312 Second detection module DETAILED DESCRIPTION
[0039] First of all, the present invention mainly relates to any means of transport with a lower cargo hold in any transport field. In particular, the present invention relates to a cargo plane with a lower cargo hold, but is not limited thereto.
[0040] The term “electrical connection” used herein is intended to describe the existence of a direct or indirect electrical signal path from one component or module to another component or module, so that the electrical signal can be transmitted from one component or module to another component or module.
[0041] As used herein, the terms "comprising," "having," "including," and variations thereof are intended to serve as open-ended transitional phrases, terms or words requiring the presence of specified elements / steps and also allowing for the presence of other elements / steps.
[0042] In the present invention, unless explicitly stated to the contrary, the terms "first", "second", etc. are not intended to indicate any difference in order, position, quantity or importance, but are merely used as labels to distinguish different positions and components, to distinguish one element, component, region and / or position from another element, component, region and / or position.
[0043] The present invention will be further described below in conjunction with specific embodiments and drawings.
[0044] The cargo hold fire detection system of the present invention is used for a prior art cargo aircraft having a main cargo hold and a lower cargo hold, such as Figure 1 The schematic diagram shows the main cargo hold 1, the lower cargo hold 2, the lower cargo hold triangle 3 and the airflow path, and the airflow path is indicated by a solid arrow. When the sealing condition between the lower cargo hold triangle and the interior wall panel of the lower cargo hold is not good, the airflow easily enters the lower cargo hold from the lower cargo hold triangle, and this airflow is indicated by a dotted arrow.
[0045] Figure 2The cargo hold fire detection system according to an embodiment of the present invention is schematically shown, which includes a fire prevention controller 100, a main cargo hold fire alarm unit 200 and a lower cargo hold fire alarm unit 300. The main cargo hold fire alarm unit 200 and the lower cargo hold fire alarm unit 300 are independent fire detection systems corresponding to the main cargo hold and the lower cargo hold. The main cargo hold fire alarm unit 200 is used to output a main cargo hold fire alarm signal to the fire prevention controller 100 when a fire occurs in the main cargo hold. Similarly, the lower cargo hold fire alarm unit 300 is used to output a lower cargo hold fire alarm signal to the fire prevention controller 100 when a fire occurs in the lower cargo hold.
[0046] In a non-limiting example, the lower cargo hold fire alarm unit 300 has a corresponding lower cargo hold fire detector 310 in the lower cargo hold, and depending on the aircraft model, the lower cargo hold may include two or more lower cargo hold fire detectors 310. The fire protection controller 100 receives and monitors the fire alarm signal a output by each lower cargo hold fire detector 310. Each main cargo hold fire detector and each lower cargo hold fire detector of the cargo aircraft are electrically connected to the fire protection controller 100 via a bus or hard wire.
[0047] In a non-limiting example, the lower cargo compartment fire detector 310 includes a first detection module 311 and a second detection module 312. In a preferred embodiment, the first detection module 311 is a smoke detection module, and the second detection module 312 is a CO gas detection module or a temperature detection module, which will be described in detail below.
[0048] Considering that the fire in the main cargo hold and the lower cargo hold generally goes through a process from smoldering to open flame. In the early stage of the fire, the main feature is smoldering, which produces a lot of smoke. Therefore, the first detection module 311 is preferably a smoke detection module. The smoke detection module monitors the amount of smoke in the cargo hold, and when the amount of smoke reaches the alarm threshold, it outputs a module alarm signal b about the smoke.
[0049] The smoke produced by the combustion of most substances contains CO and CO2 gases. Under normal circumstances, the air contains about 0.04% CO2, and the CO2 content will be higher in a closed cargo hold. Therefore, detecting changes in CO2 is prone to cause false alarms, and in the smoldering stage, due to insufficient O2, incomplete combustion causes a high CO gas content, and the detection of CO gas is more stable. Therefore, the second detection module 312 can be a CO gas detection module. The CO gas detection module monitors the absolute value and change rate of the CO gas concentration in the cargo hold. When the absolute value and change rate of the CO gas concentration in the hold reach the alarm threshold, it outputs a module alarm signal b about CO gas. Using a smoke and CO gas composite fire detector to simultaneously collect smoke and CO gas information during a fire, instead of the traditional single smoke information, can effectively reduce the probability of false alarms.
[0050] The temperature changes significantly during the open flame stage, and combustion generates a large amount of heat, so the second detection module 312 can also be a temperature detection module. The temperature detection module monitors the temperature value and change rate of the temperature in the cargo hold. When the temperature value and change rate in the hold reach the alarm threshold, it outputs a module alarm signal b about the temperature. The use of a smoke and temperature composite fire detector simultaneously collects smoke and temperature information during the fire process, replacing the traditional single smoke information, which can effectively reduce the probability of false alarms.
[0051] However, considering that in the smoldering stage, the heat radiated by the smoldering fire is small, so the temperature change is small, and in the open flame stage, the gas concentration will decrease, so if the three factors of smoke, temperature and CO gas are used together to judge the fire, the judgment condition is too strict and it is easy to cause missed alarms. Therefore, the second detection module 312 can be selected from either a CO gas detection module or a temperature detection module.
[0052] The lower cargo hold fire alarm method according to an embodiment of the present invention will be described below.
[0053] First, the fire protection controller 100 monitors the working state of the corresponding lower cargo hold fire detector 310 of the lower cargo hold in real time. The working state of each lower cargo hold fire detector 310 includes three states: normal, false alarm and fault. When the first detection module 311 and the second detection module 312 of any lower cargo hold fire detector 310 are normal, the fire protection controller 100 determines that the lower cargo hold fire detector 310 is in a normal state. The false alarm state and the fault state will be described in detail below.
[0054] In order to reduce false alarms of the fire detection system in the lower cargo hold, when at least two lower cargo hold fire detectors 310 are in a normal state, the judgment condition of the fire protection controller 100 is "AND" logic. Specifically, when the at least two lower cargo hold fire detectors 310 all output a fire alarm signal a, the fire protection controller 100 determines that a fire has occurred in the lower cargo hold and outputs a lower cargo hold fire alarm signal, which is sent to the control panel, alarm device, etc., to remind crew members that a fire has occurred in the lower cargo hold.
[0055] Furthermore, when at least one of the at least two lower cargo hold fire detectors 310 is in a faulty state or a false alarm state, the determination condition of the fire protection controller 100 is an "or" logic. Specifically, when any lower cargo hold fire detector 310 in a normal state outputs a fire alarm signal a, the fire protection controller 100 determines that a fire has occurred in the lower cargo hold and outputs a lower cargo hold fire alarm signal.
[0056] Figure 3It is a schematic diagram of the fire alarm logic of the lower cargo hold fire detector 310 of the cargo hold fire detection system according to an embodiment of the present invention. The following will further explain how the lower cargo hold fire detector 310 determines the need to output the fire alarm signal a from the module alarm signal b output by its first detection module 311 and the second detection module 312.
[0057] Depending on whether the fire protection controller 100 has received the main cargo hold fire alarm signal, each lower cargo hold fire detector 310 will execute two different alarm logics to output a fire alarm signal a.
[0058] When the fire protection controller 100 has received the main cargo hold fire alarm signal, each lower cargo hold fire detector 310 executes the first alarm logic to output the fire alarm signal a. The first alarm logic is the alarm logic used to reduce the probability of false alarms in the lower cargo hold in the event of a fire in the main cargo hold.
[0059] When the fire protection controller 100 does not receive the main cargo hold fire alarm signal, each lower cargo hold fire detector 310 executes the second alarm logic to output the fire alarm signal a. The second alarm logic is the alarm logic usually used.
[0060] When the fire protection controller 100 has received the fire alarm signal from the main cargo hold of the aircraft, the first alarm logic executed by each lower cargo hold fire detector 310 is an "AND" logic, wherein the first alarm logic includes: the fire protection controller 100 intervenes and controls the lower cargo hold fire detector 310, so that when the first detection module 311 and the second detection module 312 of the lower cargo hold fire detector 310 both output a module alarm signal b, the fire protection controller 100 determines that the lower cargo hold fire detector 310 outputs a fire alarm signal a.
[0061] Preferably, the first alarm logic also includes a step of determining that the lower cargo hold fire detector 310 is in a false alarm state. Specifically, the first alarm logic also includes: when only one of the first detection module 311 and the second detection module 312 of the lower cargo hold fire detector 310 outputs a module alarm signal b, and the other does not output a module alarm signal, the fire protection controller 100 determines that the lower cargo hold fire detector 310 is in a false alarm state rather than a normal state, and isolates the lower cargo hold fire detector 310, and does not adopt its fire alarm signal a.
[0062] Further, when the fire protection controller 100 determines that the lower cargo hold fire detector 310 is in a false alarm state, the first alarm logic also includes: after only one detection module among its first detection module 311 and the second detection module 312 outputs the module alarm signal b and stops outputting for a predetermined time, the fire protection controller 100 determines that the lower cargo hold fire detector 310 has returned to a normal state instead of being in a false alarm state.
[0063] Taking into account that each detection module of each lower cargo hold fire detector 310 of the lower cargo hold cannot avoid failure, the first alarm logic also includes the continued use of the lower cargo hold fire detector 310 in the event of a detection module failure.
[0064] When the first detection module 311 is a smoke detection module and the second detection module 312 is a carbon monoxide detection module or a temperature detection module, the first alarm logic also includes: when the first detection module 311 is normal and the second detection module 312 is faulty, the fire protection controller 100 determines that the lower cargo hold fire detector 310 is in a faulty state, and the fire protection controller 100 does not adopt the possible fire alarm signal a of the lower cargo hold fire detector 310.
[0065] When the first detection module 311 fails and the second detection module 312 is normal, the fire protection controller 100 determines that the lower cargo hold fire detector 310 is in a normal state, and further: when the second detection module 312 outputs a module alarm signal b, the fire protection controller 100 determines that the lower cargo hold fire detector 310 outputs a fire alarm signal a.
[0066] In the case that both the first detection module 311 and the second detection module 312 fail, the fire protection controller 100 determines that the lower cargo hold fire detector 310 is in a faulty state, and the fire protection controller 100 does not adopt a possible fire alarm signal a of the lower cargo hold fire detector 310.
[0067] In addition, when the fire protection controller 100 does not receive the fire alarm signal from the main cargo hold of the aircraft, the second alarm logic executed by each lower cargo hold fire detector 310 is an "or" logic, wherein the second alarm logic includes: when at least one of the first detection module 311 and the second detection module 312 outputs a module alarm signal b, the lower cargo hold fire detector 310 outputs a fire alarm signal a.
[0068] Taking into account that each detection module of each lower cargo hold fire detector 310 in the lower cargo hold cannot avoid failure, the second alarm logic also includes the continued use of the lower cargo hold fire detector 310 in the event of a detection module failure.
[0069] When only one of the first detection module 311 and the second detection module 312 is normal, the fire protection controller 100 determines that the lower cargo hold fire detector 310 is in a normal state, and further: when the normal detection modules in the first detection module 311 and the second detection module 312 output module alarm signal b, the lower cargo hold fire detector 310 outputs a fire alarm signal a.
[0070] In the case that both the first detection module 311 and the second detection module 312 fail, the fire protection controller 100 determines that the lower cargo hold fire detector 310 is in a faulty state, and the fire protection controller 100 does not adopt a possible fire alarm signal a of the lower cargo hold fire detector 310.
[0071] In order to make the objectives, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions of the present invention are clearly and completely described above in conjunction with the specific embodiments of the present invention and the accompanying drawings.
[0072] Although various embodiments have been described above, it should be understood that the embodiments described are part of the embodiments of the present invention, rather than all embodiments, and they are presented in an exemplary rather than limiting manner. It is obvious to those skilled in the relevant art that the disclosed subject matter can be implemented in other specific forms without departing from its spirit and essential features.
[0073] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention. The present disclosure also includes various modifications and modifications within the equivalent scope. In addition, various combinations and methods, further including only one element, more than one or less than one other combinations and methods also belong to the scope and scope of thought of the present disclosure.
Claims
1. A lower cargo hold fire alarm method, characterized in that: The lower cargo hold fire alarm method comprises: In the case where at least two lower cargo hold fire detectors (310) are in a normal state, when at least two lower cargo hold fire detectors (310) output a fire alarm signal (a), the fire protection controller (100) outputs a lower cargo hold fire alarm signal; and In the case where at least one of the at least two lower cargo hold fire detectors (310) is in a fault state or a false alarm state, when any of the lower cargo hold fire detectors (310) in a normal state outputs the fire alarm signal (a), the fire protection controller (100) outputs the lower cargo hold fire alarm signal, wherein, in the case where the fire protection controller (100) has received a main cargo hold fire alarm signal, the lower cargo hold fire detector (310) executes a first alarm logic to output the fire alarm signal (a), and wherein, in the case where the main cargo hold fire alarm signal has not been received, the lower cargo hold fire detector (310) executes a second alarm logic to output the fire alarm signal (a), The first alarm logic includes: When the first detection module (311) and the second detection module (312) of the lower cargo hold fire detector (310) both output a module alarm signal (b), the fire protection controller (100) determines that the lower cargo hold fire detector (310) outputs a fire alarm signal (a), and The second alarm logic includes: When at least one of the first detection module (311) and the second detection module (312) outputs the module alarm signal (b), the lower cargo hold fire detector (310) outputs a fire alarm signal (a).
2. The lower cargo hold fire alarm method according to claim 1, characterized in that: The first alarm logic further includes: When only one of the first detection module (311) and the second detection module (312) of the lower cargo hold fire detector (310) outputs the module alarm signal (b), the fire protection controller (100) determines that the lower cargo hold fire detector (310) is in a false alarm state rather than a normal state, and isolates the lower cargo hold fire detector (310).
3. The lower cargo hold fire alarm method according to claim 2, characterized in that: The first alarm logic further includes: In the case where the fire protection controller (100) determines that the lower cargo hold fire detector (310) is in a false alarm state, after only one of the first detection module (311) and the second detection module (312) outputs the module alarm signal (b) and stops outputting for a predetermined time, the fire protection controller (100) determines that the lower cargo hold fire detector (310) has returned to a normal state instead of being in a false alarm state.
4. The lower cargo hold fire alarm method according to claim 1, characterized in that: In the case where the first detection module (311) is a smoke detection module, and the second detection module (312) is a carbon monoxide gas detection module or a temperature detection module, The first alarm logic further includes: When the first detection module (311) is normal and the second detection module (312) is faulty, the fire protection controller (100) determines that the lower cargo hold fire detector (310) is in a faulty state, and the fire protection controller (100) does not adopt the fire alarm signal (a) of the lower cargo hold fire detector (310); When the first detection module (311) fails and the second detection module (312) is normal, the fire protection controller (100) determines that the lower cargo hold fire detector (310) is in a normal state, and further: when the second detection module (312) outputs the module alarm signal (b), the fire protection controller (100) determines that the lower cargo hold fire detector (310) outputs the fire alarm signal (a); When both the first detection module (311) and the second detection module (312) fail, the fire protection controller (100) determines that the lower cargo hold fire detector (310) is in a faulty state, and the fire protection controller (100) does not adopt the fire alarm signal (a) of the lower cargo hold fire detector (310).
5. The lower cargo hold fire alarm method according to claim 1, characterized in that: The second alarm logic further includes: In the case that only one of the first detection module (311) and the second detection module (312) is normal, the fire protection controller (100) determines that the lower cargo hold fire detector (310) is in a normal state, and further: when the normal only one of the first detection module (311) and the second detection module (312) outputs the module alarm signal (b), the lower cargo hold fire detector (310) outputs the fire alarm signal (a); When both the first detection module (311) and the second detection module (312) fail, the fire protection controller (100) determines that the lower cargo hold fire detector (310) is in a faulty state, and the fire protection controller (100) does not adopt the fire alarm signal (a) of the lower cargo hold fire detector (310).
6. A cargo hold fire detection system, characterized in that: The cargo hold fire detection system comprises: Fire protection controller (100); a main cargo hold fire alarm unit (200), which provides a main cargo hold fire alarm signal when a fire occurs in the main cargo hold; and A lower cargo hold fire alarm unit (300), the lower cargo hold fire alarm unit comprising at least two lower cargo hold fire detectors (310), each of the lower cargo hold fire detectors (310) comprising a first detection module (311) and a second detection module (312), wherein the first detection module (311) is a smoke detection module, and the second detection module (312) is a carbon monoxide gas detection module or a temperature detection module.
7. A fire detector, characterized in that: The fire detector comprises: A first detection module (311) and a second detection module (312), wherein the first detection module (311) is a smoke detection module, and the second detection module (312) is a carbon monoxide gas detection module or a temperature detection module.