Fire-fighting fire alarm structure

Abstract

The invention relates to the technical field of fire alarm devices, in particular to a fire-fighting fire alarm structure which comprises a protective shell, a ventilation cover is detachably mounted at the bottom end of the protective shell, a stabilizing plate is fixedly mounted at the inner end of the protective shell, a speed reduction disc is rotatably mounted at the center of the stabilizing plate, and a driving rod is arranged at the bottom end of the speed reduction disc. Fan blades are fixedly installed at the ends, away from the speed reduction disc, of the driving rods through bolts, an air suction barrel used for sucking air is fixedly installed at the upper end of the inner side of the stabilizing plate, a stabilizing frame is fixedly installed at the bottom end of the inner side of the stabilizing plate and located on the left side of the air suction barrel, and a metering device used for recognizing whether smoke is fire gas or not is arranged at the inner end of the stabilizing frame; according to the invention, by weighing the mass of the smoke particles, whether the smoke is fire smoke or not is judged, so that the fire smoke and the cigarette smoke can be distinguished, and false alarms can be reduced.

Description

Technical Field

[0001] The invention relates to the technical field of fire alarm devices, in particular to a fire alarm structure. Background Art

[0002] A fire alarm is a device used to detect early signs of fire and sound an alarm. It is widely used in homes, commercial buildings, industrial sites and other occasions. With the rapid development of modern society and the acceleration of urbanization, the height and complexity of buildings are increasing, and the risk of fire is also increasing accordingly. Therefore, the design and performance requirements of fire alarms have become more stringent and diversified.

[0003] After searching, it was found that the prior art publication number was CN114387757A, which disclosed a fire alarm for fire protection engineering, including a built-in top shell and a bottom shell, the built-in top shell was fixedly installed on the top of the bottom shell, and the bottom of the bottom shell was fixedly inlaid with a number of hemispherical sound amplification and smoke guide shells, and the top of the hemispherical sound amplification and smoke guide shells was fixedly installed with a protective elbow, and the protective elbow was connected to the built-in top shell. The fire alarm for fire protection engineering is reasonably designed, and a hemispherical sound amplification and smoke guide shell is installed on the bottom of the bottom shell, and the hemispherical sound amplification and smoke guide shell is connected to the built-in top shell through the protective elbow. When a fire occurs, the scheme can guide the smoke into the built-in top shell through the protective elbow through the hemispherical sound amplification and smoke guide shell, which can prevent the flame from directly burning the smoke sensor and can also detect normally, ensuring that the whole can continue to work.

[0004] Therefore, based on the above retrieval and combined with existing technologies, in existing fire alarms, since the alarm cannot accurately identify the smoke generated by cigarettes and the smoke of real-time fires, false alarms may occur. Long-term misidentification makes users inevitably lose trust in the alarm, resulting in unnecessary emergency response and evacuation, and the practicality is not strong. For this reason, we propose a fire alarm structure. Summary of the invention

[0005] The object of the present invention is to provide a fire alarm structure to solve the problems raised in the above background technology.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a fire alarm structure, comprising a protective shell, a ventilation cover is detachably mounted on the bottom end of the protective shell, a mesh cover for blocking water vapor is fixedly mounted on the inner end of the ventilation cover, a stabilizing seat is detachably mounted on the upper end of the protective shell, a circuit board is detachably mounted on one end of the stabilizing seat close to the ventilation cover, a sensor module is fixedly mounted on the bottom end of the circuit board, the sensor module and the circuit board are electrically connected through a wire, a stabilizing plate is fixedly mounted on the inner end of the protective shell, the stabilizing plate is located above the ventilation cover, a speed reduction disc is rotatably mounted at the center of the stabilizing plate, a driving rod is provided at the bottom end of the speed reduction disc, a fan blade is fixedly mounted on the end of the driving rod away from the speed reduction disc by bolts, and the fan blade is used to suck the surrounding gas into the protective shell when it rotates, an exhaust cylinder for extracting air is fixedly mounted on the inner upper end of the stabilizing plate, a stabilizing frame is fixedly mounted on the inner bottom end of the stabilizing plate, the stabilizing frame is located on the left side of the exhaust cylinder, and a metering device for identifying whether the smoke is fire gas is provided at the inner end of the stabilizing frame.

[0007] As a further solution of the present invention, a driving motor is fixedly mounted on one end of the stabilizing plate away from the stabilizing frame, a driving disk is fixedly mounted on the output end of the driving motor, and the reduction disk is sleeved on the outer surface of the driving disk.

[0008] As a further solution of the present invention, a driving gear is fixedly installed on the bottom end of the driving disk, and a plurality of passive gears are rotatably installed on the inner end of the reduction disk. The plurality of passive gears are arranged in a ring shape, and the torque is increased to achieve force amplification through the meshing transmission of the plurality of gears.

[0009] As a further solution of the present invention, a gear ring is sleeved on the inner end of the reduction plate, one end of the gear ring away from the driving gear is fixedly connected to the driving rod, and the gear ring is meshed with a plurality of driven gears.

[0010] As a further solution of the present invention, an electromagnetic connector is slidably connected between the gear ring and the reduction plate, and when the electromagnetic connector is energized, it generates magnetic force to attract the gear ring and the reduction plate, thereby enabling the gear ring to drive the reduction plate to rotate when it rotates, and two brushes are fixedly installed on one end of the stabilizing plate close to the reduction plate, the brush head of the brush is in contact with the conductive end of the electromagnetic connector, and the brush is electrically connected to the circuit board through a wire.

[0011] As a further solution of the present invention, the metering device includes an air cylinder, which is arranged on the inner side of the stabilizing frame, and the air cylinder and the stabilizing frame are connected by a micro-spring, and inductance coils are fixedly installed on both ends of the inner side of the stabilizing frame, and permanent magnets are fixedly installed on both ends of the left and right sides of the air cylinder, and the permanent magnets and the inductance coils are parallel to each other. The quality of the current smoke is detected by inducing the change of the magnetic field through inductance, thereby realizing the judgment whether the current area is a precursor of fire.

[0012] As a further solution of the present invention, an air pipe is fixedly installed on the bottom end of the stabilizing frame, a hole is opened at one end of the air cylinder close to the air pipe, an output end of the air pipe passes through the hole and extends into the air cylinder, and a sealing film is fixedly installed at one end of the air cylinder close to the air pipe, the sealing film is fixedly sleeved on the outer wall of the air pipe, and an electromagnetic valve is fixedly connected to one end of the air pipe away from the air cylinder.

[0013] As a further solution of the present invention, the input end of the air pipe is fixedly connected to the output end of the vacuum cylinder, the inner end of the vacuum cylinder is slidably connected to a piston, the end of the piston away from the air pipe is fixedly connected to a driving rope, and the free end of the driving rope is wound around the outer surface of the speed reducer, and a plug is provided at the input end of the air pipe, and the plug is located inside the vacuum cylinder.

[0014] As a further solution of the present invention, a pry bar is rotatably installed on the inner left end of the vacuum cylinder, and the pry bar is rotatably connected to the plug plate at one end close to the gas pipe. A slide groove is provided at the inner bottom end of the vacuum cylinder, and a movable rod is slidably installed in the slide groove. The bottom end of the pry bar is rotatably connected to the movable rod, and an abutment plate is fixedly installed on the right end of the movable rod. By evacuating the air inside the air storage cylinder so that it can enter the next cycle, sustainable utilization of the device can be achieved.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. The present invention can weigh the mass of smoke particles to determine whether the smoke is fire smoke, thereby achieving the ability to distinguish between fire smoke and cigarette smoke, which helps reduce false alarms;

[0017] 2. When the present invention is in use, the difference in particle size and concentration between fire smoke and cigarette smoke can help identify the source of smoke more accurately. By combining particle size weighing with advanced sensing technology, a more intelligent smoke monitoring system can be implemented, which can automatically adjust the alarm strategy and improve the intelligence level of the overall monitoring device. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of a fire alarm structure;

[0019] Figure 2 It is a schematic diagram of the structure inside a fire alarm structure;

[0020] Figure 3 This is a disassembly diagram of a fire alarm structure;

[0021] Figure 4 It is a schematic diagram of the structure at the stabilizing plate;

[0022] Figure 5 This is the disassembly diagram of the speed reducer and the drive plate;

[0023] Figure 6 This is the position relationship diagram of the brush and the electromagnetic connector;

[0024] Figure 7 Schematic diagram of the structure of the metering device;

[0025] Figure 8 It is a schematic diagram of the structure inside the gas reservoir;

[0026] Fig. 9 It is a schematic diagram of the structure inside the vacuum pump;

[0027] Fig.10 for Fig. 9 The structural diagram at A in the middle;

[0028] Fig.11 This is an enlarged view of the structure at the plug.

[0029] In the figure: 1. protective shell; 2. ventilation cover; 3. stabilizing seat; 4. battery; 5. sensor module; 6. drive motor; 7. circuit board; 11. stabilizing plate; 12. mesh cover;

[0030] 101, deceleration plate; 102, driving rod; 103, fan blade; 104, driving rope; 105, driving plate; 106, driving gear; 107, driven gear; 108, gear ring; 109, brush; 110, electromagnetic connector;

[0031] 201, vacuum pump; 202, return spring; 203, passive rod; 204, piston; 205, movable rod; 206, abutment sheet; 207, plug sheet; 208, pry bar; 209, abutment sheet;

[0032] 301. Stabilizing frame; 302. Air cylinder; 303. Micro spring; 304. Air pipe; 305. Solenoid valve; 306. Permanent magnet; 307. Inductor coil; 308. Sealing film. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] Example 1: Please refer to Figures 1 to 3 A fire alarm structure includes a protective shell 1, a ventilation cover 2 is detachably mounted on the bottom end of the protective shell 1 through bolts, a mesh cover 12 for blocking water vapor is fixedly mounted on the inner end of the ventilation cover 2, and the mesh cover 12 is made of metal, and the metal has good thermal conductivity, so that water vapor will condense into water droplets when it encounters the mesh cover 12, and then slide down from the bottom, a stabilizing seat 3 is detachably mounted on the upper end of the protective shell 1 through bolts, and a circuit board 7 is detachably mounted on the end of the stabilizing seat 3 close to the ventilation cover 2 through bolts, and specifically, a bridge circuit, an oscillation circuit, a microprocessor, a force-sensitive electrical sensor, The signal adjustment circuit and the alarm module, and the working principles and connection relationships of the above components are all existing mature technologies, which will not be elaborated here. More specifically, a battery 4 is fixedly installed at one end of the circuit board 7 close to the ventilation cover 2, and the battery 4 is electrically connected to the circuit board 7 through a wire, which is used to provide power to the circuit board 7 and the components. A sensor module 5 is fixedly installed at the bottom of the circuit board 7, and the sensor module 5 is electrically connected to the circuit board 7 through a wire. The sensor module 5 is specifically a photoelectric sensor, and can also be an ion sensor, which is used to detect early signs of fire, and is an existing mature technology, which will not be elaborated here.

[0035] A stabilizing plate 11 is fixedly installed at the inner end of the protective shell 1, and the stabilizing plate 11 is located above the ventilation cover 2. A speed reduction disc 101 is rotatably installed at the center of the stabilizing plate 11. A driving rod 102 is provided at the bottom end of the speed reduction disc 101. A fan blade 103 is fixedly installed at one end of the driving rod 102 away from the speed reduction disc 101 by bolts. When the fan blade 103 rotates, it is used to suck the surrounding gas into the protective shell 1. Specifically, a circular groove is opened at the inner end of the ventilation cover 2, and the fan blade 103 is located in the circular groove, so that the fan blade 103 can blow more air into the protective shell 1 when it rotates;

[0036] An air extraction cylinder 201 for extracting air is fixedly installed on the inner upper end of the stabilizing plate 11, and a stabilizing frame 301 is fixedly installed on the inner bottom end of the stabilizing plate 11. The stabilizing frame 301 is located on the left side of the air extraction cylinder 201, and a protective glass plate (not shown in the figure) is fixedly installed on the outer surface of the stabilizing frame 301 to prevent external pollutants from entering therein and causing damage to the device. A metering device for identifying whether the smoke is fire gas is provided at the inner end of the stabilizing frame 301;

[0037] See also Figure 4 , 5 6. A driving motor 6 is fixedly mounted on one end of the stabilizing plate 11 away from the stabilizing frame 301. A driving disc 105 is fixedly mounted on the output end of the driving motor 6, and a reduction disc 101 is sleeved on the outer surface of the driving disc 105. Specifically, a driving gear 106 is fixedly mounted on the bottom end of the driving disc 105. A plurality of passive gears 107 are rotatably mounted on the inner end of the reduction disc 101. The plurality of passive gears 107 are arranged in a ring shape. A gear ring 108 is rotatably sleeved on the inner end of the reduction disc 101. An end of the gear ring 108 away from the driving gear 106 is fixedly connected to the driving rod 102, and the gear ring 108 is meshed with the plurality of passive gears 107. The gear ring 108 and the reduction disc 101 are both made of stainless steel.

[0038] Specifically, an electromagnetic connector 110 is slidably connected between the gear ring 108 and the reduction disc 101, and when the electromagnetic connector 110 is energized, a magnetic force is generated to attract the gear ring 108 and the reduction disc 101, so that the gear ring 108 can drive the reduction disc 101 to rotate when it rotates. Two brushes 109 are fixedly installed on one end of the stabilizing plate 11 close to the reduction disc 101, and the brush head of the brush 109 is in contact with the conductive end of the electromagnetic connector 110, and the brush 109 is electrically connected to the circuit board 7 through a wire. Specifically, the brush 109 is fixedly connected At the bottom end of the stabilizing plate 11, two grooves are provided at the bottom end of the electromagnetic connector 110. More specifically, the electromagnetic connector 110 is composed of an iron ring and a coil. The groove is provided at the lower end of the iron ring, and the two terminals of the coil in the electromagnetic connector 110 are located in the groove at the lower end of the iron ring. More specifically, two copper ring pieces are fixedly connected in the groove at the lower end of the iron ring, and the copper ring piece and the iron ring are separated by insulating rubber, and the two terminals of the coil in the electromagnetic connector 110 are fixedly connected to the copper ring piece, and the brush 109 is in contact with the copper ring piece.

[0039] Example 2: Please refer to Figure 7 , 8 A fire alarm structure is provided. Based on the first embodiment, the metering device includes an air cylinder 302, which is arranged on the inner side of a stabilizing frame 301, and the air cylinder 302 is connected to the stabilizing frame 301 through a plurality of micro springs 303. The micro springs 303 can be compressed by only a slight downward pressure of gravity. Inductance coils 307 are fixedly installed on both the left and right ends of the inner side of the stabilizing frame 301. The inductance coils 307 are electrically connected to the force-sensitive electric sensor through a wire. Permanent magnets 306 are fixedly installed on both the left and right ends of the air cylinder 302, and the permanent magnets 306 and the inductance coils 307 are parallel to each other.

[0040] The gas cylinder 302 is vacuum. When the air containing smoke particles enters the gas cylinder 302, the gas cylinder 302 moves downward due to the smoke particles (the smoke particles have weight). The weight of the smoke is calculated by detecting the change in inductance caused by the downward movement of the permanent magnet 306 through the inductance coil 307. The particle density in the same air volume unit in ordinary smoke (such as the smoke generated by burning cigarettes) and the smoke generated by fire is different, and the weight is also different. For example, the particle density in ordinary smoke is 1-3, and the particle density in fire smoke is 10 or more. It is judged whether there is a precursor of fire in the current environment. When the area of ​​the permanent magnet 306 is constant and the number of turns of the inductance coil 307 is constant, then the basic formula based on inductance (L) is:

[0041]

[0042] Where μ is the magnetic permeability (including the magnetic permeability of air or core material), N is the number of turns of the coil, A is the cross-sectional area of ​​the coil, and l is the length of the magnetic circuit. Based on the inductance change ΔL and the mass m of the particles in the smoke, P The relationship is expressed as:

[0043] ΔL=k·m P

[0044] Where k is a calibration constant (obtained through experiments). At this time, the mass of smoke particles can be deduced from this formula as:

[0045]

[0046] At this time, the weight of the gas cylinder 302 itself is W0, and the total weight after being filled with smoke and air is W, which can be calculated by W = W0 + m p The calculation shows that the quality of the smoke air can be deduced, and from this it can be inferred whether the current smoke is smoke generated by a fire;

[0047] In practical applications, specific factors affecting inductance changes may be taken into account, such as air flow, temperature changes, etc. Through the oscillation circuit, the change in inductance can be indirectly calculated using the change in frequency:

[0048]

[0049] Where f is the oscillation frequency, and C is the capacitance in the circuit. Whenever smoke enters the gas cylinder 302, particles will be left in the gas cylinder 302. The weight left last time needs to be subtracted during the next weighing to compensate for the error. In the first measurement, the smoke mass is calculated to be This mass is then recorded as the mass m left over from last time. residual, in the second or subsequent weighing, the inductance change obtained by inductance measurement is ΔL n , calculate the newly measured smoke particle mass m by the formula P,n :

[0050]

[0051] At this time, we need to calculate the current total mass W n , including the weight W0 of the gas cylinder 302 itself and the currently measured mass m of the smoke particles p,n , by W n =W0+m p,n Calculated;

[0052] Each weighing needs to subtract the mass of the remaining smoke particles to obtain the actual mass of the newly added smoke particles. The actual mass of the newly added smoke particles is m p,new is the mass of smoke particles currently measured minus the mass left over from last time:

[0053] m p,new =m p,n -m residual

[0054] And update the last remaining mass m residual The mass of smoke particles currently measured for the next weighing: m residual =m p,n ;

[0055] Then the actual mass of the newly added smoke particles is: Current total weight: Updated legacy smoke particle quality: It is worth noting that all the above calculations are completed by the microprocessor in the circuit board 7;

[0056] An air pipe 304 is fixedly installed at the bottom end of the stabilizing frame 301, and a hole is opened at one end of the air storage cylinder 302 close to the air pipe 304. The output end of the air pipe 304 passes through the hole and extends into the air storage cylinder 302. Specifically, the outer wall of the air pipe 304 does not contact the inner wall of the hole, and a sealing film 308 is fixedly installed at one end of the air storage cylinder 302 close to the air pipe 304. The sealing film 308 is fixedly sleeved on the outer wall of the air pipe 304, thereby avoiding the outer wall of the air pipe 304 from contacting the air storage cylinder 302, and the sealing film 308 effectively avoids the generation of friction, thereby increasing the sensitivity of the device, and the end of the air pipe 304 away from the air storage cylinder 302 is fixedly connected to the solenoid valve 305, and the solenoid valve 305 is connected to the circuit board 7 through a guide electrical connection;

[0057] The input end of the air pipe 304 is fixedly connected to the output end of the air pump 201, and the inner end of the air pump 201 is slidably connected to a piston 204, and a sealing rubber ring is fixedly installed on the outer surface of the piston 204, and the outer surface of the sealing rubber ring is tightly fitted with the inner wall of the air pump 201 to increase the air tightness. The end of the piston 204 away from the air pipe 304 is fixedly connected to a driving rope 104, and the free end of the driving rope 104 is wound around the outer surface of the speed reduction plate 101. Specifically, the piston 204 and the air pump 201 are connected via a return spring 202. A plug 207 is provided at the input end of the air pipe 304, and the plug 207 is located inside the air pump 201. More specifically, a sealing rubber ring is fixedly installed at one end of the plug 207 close to the air pipe 304 to increase the air tightness.

[0058] See also Fig. 9 , 10 11. A pry bar 208 is rotatably installed at the left inner end of the vacuum cylinder 201. One end of the pry bar 208 close to the gas pipe 304 is rotatably connected to the plug 207. A slide groove is provided at the inner bottom end of the vacuum cylinder 201. A movable rod 205 is slidably installed in the slide groove. The bottom end of the pry bar 208 is rotatably connected to the movable rod 205. An abutment sheet 206 is fixedly installed at the right end of the movable rod 205. When the piston 204 moves to the right, it abuts and pushes the abutment sheet 206. The abutment sheet 206 moves through the movable rod 205 to pull the passive rod 203 to rotate. Subsequently, the upper end of the rotating passive rod 203 pushes the plug 207 to move toward the gas pipe 304, so that the gas pipe 304 is sealed.

[0059] More specifically, a limit ring is fixedly installed on the inner end of the vacuum cylinder 201, and the limit ring is located on the left side of the piston 204, thereby preventing the piston 204 from moving excessively and damaging the plug 207. An air hole is opened at the bottom end of the vacuum cylinder 201, and a plug 209 is fixedly installed on the outer surface of the movable rod 205. The plug 209 is located at the air hole. When the movable rod 205 moves to the left, the plug 209 blocks the air hole, and vice versa.

[0060] The working principle of the present invention is:

[0061] During use, when the sensor module detects smoke, it sends a model number to the microprocessor, and then the microprocessor transmits a signal through the circuit board 7 and the wires, so that the output end of the drive motor 6 drives the fan blade 103 to rotate. When the fan blade 103 rotates, it sucks the surrounding smoke into the protective shell 1, and then the solenoid valve 305 is in an open state. Under the action of atmospheric pressure, the smoke enters the gas storage cylinder 302 in a vacuum state from the solenoid valve 305. Then the solenoid valve 305 is immediately closed, and the force-sensitive electrical sensor uses the obtained gravity to be transmitted back to the microprocessor. The microprocessor calculates and decides whether the smoke is fire smoke. If it is ordinary smoke, it is ignored. If it is fire smoke, the alarm module responds in time and sounds an alarm.

[0062] When it is ordinary smoke, it is necessary to extract the residual smoke in the gas storage cylinder 302. After the electromagnetic connector 110 is energized, it generates magnetic force and attracts the gear ring 108 and the speed reduction plate 101, so that the gear ring 108 can drive the speed reduction plate 101 to rotate, and then the driving motor 6 is reversed, and the piston 204 is pulled away from the gas pipe 304 through the driving rope 104, and the smoke in the gas storage cylinder 302 is extracted. When the piston 204 contacts the abutment sheet 206, the piston 204 pushes the abutment sheet 206 to move, and the abutment sheet 206 moves through the activity Rod 205 pulls passive rod 203 to rotate, and then the upper end of the rotating passive rod 203 pushes plug 207 to move toward the direction of air pipe 304, so that air pipe 304 is sealed, and then plug 209 exposes the air vent at the bottom of vacuum cylinder 201, and then the air pressure inside vacuum cylinder 201 is balanced with the external air pressure. Then, under the action of atmospheric pressure, plug 207 is firmly fitted with the input end of air pipe 304. At this time, the driving motor 6 is reversed, so that the piston 204 returns to its initial state under the action of the return spring 202.

[0063] Example:

[0064] Assume that the initial weight of the gas cylinder 302 is W0=1000 g;

[0065] The mass of smoke particles caused by the change in inductance ΔL1 during the first weighing

[0066] During the second weighing, the mass of smoke particles caused by the inductance change ΔL2 is

[0067] Record the first remaining mass: m residual =m p1 =50g;

[0068] Calculate the actual newly added mass during the second weighing: m p,new =m p2 -m residual=70g-50g=20g;

[0069] Update legacy quality: m residual =m p2 =70g.

[0070] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed in the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A fire alarm structure, comprising a protective shell (1), characterized in that: A ventilation cover (2) is detachably mounted on the bottom end of the protective shell (1), a mesh cover (12) for blocking water vapor is fixedly mounted on the inner end of the ventilation cover (2), a stabilizing seat (3) is detachably mounted on the upper end of the protective shell (1), a circuit board (7) is detachably mounted on one end of the stabilizing seat (3) close to the ventilation cover (2), a sensor module (5) is fixedly mounted on the bottom end of the circuit board (7), the sensor module (5) and the circuit board (7) are electrically connected via a wire, a stabilizing plate (11) is fixedly mounted on the inner end of the protective shell (1), the stabilizing plate (11) is located above the ventilation cover (2), and a stabilizing plate (11) is rotatably mounted at the center of the stabilizing plate (11). A deceleration disc (101), wherein a driving rod (102) is provided at the bottom end of the deceleration disc (101), and a fan blade (103) is fixedly installed at one end of the driving rod (102) away from the deceleration disc (101) by means of bolts, and the fan blade (103) is used to suck surrounding gas into the protective shell (1) when it rotates, and an air pump (201) for extracting air is fixedly installed at the inner upper end of the stabilizing plate (11), and a stabilizing frame (301) is fixedly installed at the inner bottom end of the stabilizing plate (11), and the stabilizing frame (301) is located on the left side of the air pump (201), and a metering device for identifying whether the smoke is fire gas is provided at the inner end of the stabilizing frame (301).

2. A fire alarm structure according to claim 1, characterized in that: A driving motor (6) is fixedly mounted on one end of the stabilizing plate (11) away from the stabilizing frame (301), a driving disk (105) is fixedly mounted on the output end of the driving motor (6), and the speed reduction disk (101) is sleeved on the outer surface of the driving disk (105).

3. A fire alarm structure according to claim 2, characterized in that: A driving gear (106) is fixedly mounted on the bottom end of the driving disc (105), and a plurality of passive gears (107) are rotatably mounted on the inner end of the reduction disc (101), wherein the plurality of passive gears (107) are arranged in a ring shape.

4. A fire alarm structure according to claim 3, characterized in that: A gear ring (108) is rotatably sleeved on the inner end of the reduction plate (101), and one end of the gear ring (108) away from the driving gear (106) is fixedly connected to the driving rod (102), and the gear ring (108) is meshed with a plurality of driven gears (107).

5. A fire alarm structure according to claim 4, characterized in that: An electromagnetic connector (110) is slidably connected between the gear ring (108) and the reduction disc (101), and when the electromagnetic connector (110) is energized, a magnetic force is generated to attract the gear ring (108) and the reduction disc (101), thereby enabling the gear ring (108) to drive the reduction disc (101) to rotate when the gear ring (108) rotates. Two brushes (109) are fixedly mounted on one end of the stabilizing plate (11) close to the reduction disc (101), and the brush heads of the brushes (109) are in contact with the conductive end of the electromagnetic connector (110), and the brushes (109) are electrically connected to the circuit board (7) via wires.

6. A fire alarm structure according to claim 1, characterized in that: The metering device comprises an air cylinder (302), the air cylinder (302) being arranged on the inner side of a stabilizing frame (301), and the air cylinder (302) and the stabilizing frame (301) being connected via a micro spring (303), an inductance coil (307) being fixedly mounted on both left and right ends of the inner side of the stabilizing frame (301), and a permanent magnet (306) being fixedly mounted on both left and right ends of the air cylinder (302), and the permanent magnet (306) and the inductance coil (307) being parallel to each other.

7. A fire alarm structure according to claim 6, characterized in that: An air pipe (304) is fixedly mounted on the bottom end of the stabilizing frame (301); a hole is formed on one end of the air storage cylinder (302) close to the air pipe (304); an output end of the air pipe (304) passes through the hole and extends into the air storage cylinder (302); a sealing film (308) is fixedly mounted on one end of the air storage cylinder (302) close to the air pipe (304); the sealing film (308) is fixedly sleeved on the outer wall of the air pipe (304); and an electromagnetic valve (305) is fixedly connected to one end of the air storage cylinder (302) away from the air storage cylinder (302).

8. A fire alarm structure according to claim 7, characterized in that: The input end of the air supply pipe (304) is fixedly connected to the output end of the air pump (201); the inner end of the air pump (201) is slidably connected to a piston (204); the end of the piston (204) away from the air supply pipe (304) is fixedly connected to a driving rope (104), and the free end of the driving rope (104) is wound around the outer surface of the speed reduction plate (101); the input end of the air supply pipe (304) is provided with a plug (207), and the plug (207) is located inside the air pump (201).

9. A fire alarm structure according to claim 8, characterized in that: A pry bar (208) is rotatably mounted on the left inner end of the vacuum cylinder (201), and one end of the pry bar (208) close to the gas pipe (304) is rotatably connected to the plug plate (207). A sliding groove is provided at the bottom inner end of the vacuum cylinder (201), and a movable rod (205) is slidably mounted in the sliding groove. The bottom end of the pry bar (208) is rotatably connected to the movable rod (205), and a contact plate (206) is fixedly mounted on the right end of the movable rod (205).

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