A gas alarm with improved protection rating

Abstract

The application relates to a gas alarm with improved protection level, and relates to the technical field of gas alarms. The gas alarm comprises a shell, a mounting plate and a circuit board. The shell is detachably connected with the mounting plate. The circuit board is located between the shell and the mounting plate. A plurality of sensors and a protective cover are fixed at one end of the circuit board away from the mounting plate. The protective cover is located on one side of the circuit board. The sensors are located inside the protective cover. A plurality of air inlet holes corresponding to the sensors are formed at one end of the protective cover away from the circuit board. Three end surfaces of the shell, which are close to the protective cover and abut against the mounting plate, are provided with a plurality of air inlet grooves. A plurality of supporting columns corresponding to the air inlet grooves are fixed to the inner wall of the shell. A retaining ring is fixed to the outer wall of the protective cover. The outer wall of the retaining ring abuts against the inner wall of the shell. The retaining ring is located between the supporting columns and the circuit board. The application has the effect of improving the protection capability of the gas alarm.

Description

Technical Field

[0001] This application relates to the field of gas alarm technology, and in particular to a gas alarm with improved protection level. Background Technology

[0002] Currently, household gas alarms are increasingly widely used in daily life. They play a crucial role in the timely detection of gas leaks and in protecting the lives and property of residents, making a positive contribution to social safety and stability. With the increasing awareness of safety among the public, the market size of household gas alarms continues to expand, and their technological development has received more attention.

[0003] Current product specifications have relatively low protection requirements for household gas alarms. In existing product designs, to ensure that gas can smoothly enter the casing and be detected by the sensor, a common practice is to create multiple air intake holes around the alarm casing, allowing the gas to more easily contact the sensor. Furthermore, to realize the various functions of the alarm, structures such as wiring harness ports, buttons, buzzers, and indicator lights are also essential design elements.

[0004] However, existing technologies have significant shortcomings. While a leaky casing allows for airflow, it also makes the circuit board susceptible to corrosion from moisture and salt spray, leading to electronic component malfunctions and affecting the alarm's quality. Accumulated dust can alter the product's performance. In humid environments, such as during the spring rains in southern China, the alarm is vulnerable to dripping water; when installed close to the ground, splashing water can also damage the product. Furthermore, an unsuitable casing structure allows cooking fumes to enter, similarly affecting product quality. Utility Model Content

[0005] To improve the protection capability of gas alarms, this application provides a gas alarm with an enhanced protection level.

[0006] This application provides a gas alarm with improved protection level, employing the following technical solution:

[0007] A gas alarm with improved protection level includes a housing, a mounting plate, and a circuit board. The housing and the mounting plate are detachably connected. The circuit board is located between the housing and the mounting plate. A plurality of sensors and a protective cover are fixedly mounted on the end of the circuit board away from the mounting plate. The protective cover is located on one side of the circuit board, and the sensors are located inside the protective cover. A plurality of air inlets corresponding to the sensors are opened on the end of the protective cover away from the circuit board. A plurality of air inlet slots are opened on the three end faces of the housing near the protective cover and abutting the mounting plate. A plurality of support pillars corresponding to the air inlet slots are fixedly mounted on the inner wall of the housing. A retaining ring is fixedly mounted on the outer wall of the protective cover. The outer wall of the retaining ring abuts against the inner wall of the housing. The retaining ring is located between the support pillars and the circuit board.

[0008] By adopting the above technical solution, the housing and mounting plate are detachably connected, facilitating assembly and maintenance; the circuit board is protected between the housing and the mounting plate; the protective cover is installed on the circuit board, separating other components from the sensor, keeping the other components in a closed state and preventing external invasion; the air inlet groove facilitates the entry of gas into the housing; the air inlet hole facilitates the entry of gas into the protective cover; the sensor is located inside the protective cover and can work normally; the setting of the support and retaining ring creates a multi-turn effect between the protective cover and the housing, preventing splashing water, smoke, dust particles from entering the sensor cavity, improving the waterproof and dustproof rating of the gas alarm, making it applicable to places with harsh environments. At the same time, the solution is simple, feasible, low-cost, easy to manufacture, and simple to produce.

[0009] Optionally, the outer casing has a button and a buzzer hole and several LED indicator holes at one end near the air inlet. A PVC film is fixed to the outer wall of the casing to cover the button, buzzer hole and LED indicator holes. A waterproof and breathable membrane is provided between the buzzer hole and the PVC film. Wiring harness ports are provided on the opposite two ends of the outer casing. A rubber shell is provided inside the wiring harness port and is sandwiched between the mounting plate and the outer casing.

[0010] By adopting the above technical solution, a PVC membrane is fixed on the outer wall of the housing to cover the buttons, buzzer holes and LED indicator holes, and a waterproof and breathable membrane is set between the buzzer holes and the PVC membrane. This can isolate the buttons, buzzer and indicator lights from the outside and prevent them from external invasion, thereby improving the protection level. A rubber shell is set inside the wire harness port and sandwiched between the mounting plate and the housing to prevent water and dust and other impurities from entering from the wire harness port, thereby enhancing the protection performance.

[0011] Optionally, a partition is provided between two adjacent air inlets inside the protective cover, the partition being used to isolate the two adjacent air inlets from the sensor.

[0012] By adopting the above technical solution, a partition is set inside the protective cover of the gas alarm to isolate adjacent air inlets and sensors, which allows for the independent installation of sensors for different gases, such as methane and carbon monoxide, for dual gas detection.

[0013] Optionally, the partition and the protective cover are detachably connected.

[0014] By adopting the above technical solution, it is easy to install sensors with irregular structures inside the protective cover, which can flexibly adapt to the installation requirements of different types of sensors and enhance the versatility and compatibility of the gas alarm.

[0015] Optionally, a light-transmitting groove is provided on the outer wall of the housing away from the air inlet slot.

[0016] By adopting the above technical solution, a light-transmitting groove is opened on the outer wall of the casing away from the air intake slot, which can realize the light transmission function of the indicator light, facilitate status indication, and also utilize the area of ​​the casing for decoration.

[0017] Optionally, the protective cover may also have a waterproof and breathable membrane fixed to its outer wall where an air inlet is provided.

[0018] By adopting the above technical solution, it is possible to further prevent fine dust from entering the interior of the protective cover in places or areas with poor air quality. At the same time, the pasting and replacement operations are simple, further improving the protection level of the gas alarm.

[0019] Optionally, the inner side of the outer shell near the mounting plate is provided with a mounting ring groove, the end face of the mounting plate near the circuit board abuts against the end face of the mounting ring groove, a plurality of first limiting blocks are fixed on the inner wall of the outer shell, and a plurality of second limiting blocks corresponding one-to-one are fixed on the end of the mounting plate near the circuit board. The first limiting blocks are provided with a first chamfer at the edge of the mounting ring groove and the circuit board away from the edge, and the second limiting blocks are provided with a second chamfer at the edge of the mounting ring groove and the circuit board.

[0020] By adopting the above technical solution, an installation ring groove is opened on the inner side of the gas alarm housing, allowing the mounting plate to abut against the end face of the installation ring groove. Corresponding first and second limiting blocks with chamfers are set to facilitate the installation and positioning of the housing and the mounting plate, making the connection between the two more stable. The chamfer setting facilitates the assembly of components, improves installation efficiency, and enhances the overall structural stability of the gas alarm.

[0021] Optionally, the protective cover has several locking blocks fixed circumferentially at one end near the circuit board, and several slots are provided on the circuit board. A third chamfer is provided at the edge of the locking blocks near the mounting plate and away from the sensor.

[0022] By adopting the above technical solution, the protective cover is installed by cooperating with the slot of the circuit board using a clip. The clip has a third chamfer, which makes the installation of the protective cover simple and convenient, improves the installation efficiency, and ensures that the protective cover can be firmly installed on the circuit board. This ensures that other components are separated from the gas sensor, that other components are kept in a closed state to prevent external invasion, and that the protective cover and the outer shell form a multi-turning effect to improve the protection level.

[0023] Optionally, a plurality of mounting brackets are fixed on the side of the mounting plate away from the circuit board and away from the protective cover. The mounting brackets are used to fix the gas alarm.

[0024] By adopting the above technical solution, a mounting bracket is set on the side of the mounting plate that is away from the circuit board and the protective cover, which makes it easy to fix the gas alarm on the wall or other fixed devices.

[0025] Optionally, the outer casing is provided with a data interface, which is located inside the PVC film.

[0026] By adopting the above technical solution, data can be read by peeling off part of the PVC film without opening the outer shell, which is convenient to operate; at the same time, the PVC film can isolate the data interface from the outside, improve the protection level, and protect the data interface from external attacks.

[0027] In summary, this application includes at least one of the following beneficial technical effects:

[0028] 1. The protective cover separates other components from the gas sensor, keeping them in a closed state and protecting them from external intrusion. It effectively prevents corrosion from moisture, salt spray, dust, etc., protects the internal components, and extends their service life.

[0029] 2. The protective cover and the outer shell form multiple turns, forcing water, dust and other substances to change their direction of movement, so that they cannot reach the sensor due to gravity, thus improving the waterproof and dustproof level and making it suitable for use in harsh environments.

[0030] 3. Buttons and LED indicator lights are covered with films, and the buzzer uses a waterproof and breathable membrane to isolate it from the outside and prevent external damage, further improving the protection level. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the overall structure of a gas alarm with improved protection level.

[0032] Figure 2 This is a schematic diagram of the outer shell.

[0033] Figure 3 This is a structural diagram of the mounting plate.

[0034] Figure 4 This is a schematic diagram of the protective cover.

[0035] Figure 5 yes Figure 1 An enlarged schematic diagram of part A in the middle.

[0036] Explanation of reference numerals in the attached drawings: 1. Outer shell; 11. Air inlet slot; 12. Support column; 13. PVC membrane; 131. Button; 132. Buzzer hole; 133. LED indicator hole; 134. Waterproof and breathable membrane; 135. Data interface; 14. Wiring harness port; 141. Rubber shell; 15. Light-transmitting slot; 16. Mounting ring slot; 17. First limiting block; 171. First chamfer; 2. Mounting plate; 21. Second limiting block; 211. Second chamfer; 23. Mounting bracket; 3. Circuit board; 31. Sensor; 32. Slot; 4. Protective cover; 41. Air inlet; 42. Retaining ring; 43. Partition; 44. Locking block; 441. Third chamfer. Detailed Implementation

[0037] The present application will be further described in detail below with reference to all the accompanying drawings.

[0038] This application discloses a gas alarm with improved protection level.

[0039] Reference Figure 1 A gas alarm with improved protection level includes a housing 1, a mounting plate 2, and a circuit board 3.

[0040] Reference Figure 1 The outer casing 1 is the external protective structure of the gas alarm. One end of the outer casing 1 is open for mounting the circuit board 3 and the mounting plate 2. The outer casing 1 includes a front panel and four side walls fixed circumferentially along the front panel. The four side walls are arranged in an alternating pattern of two long walls and two short walls. Each of the two long walls and the short wall sandwiched between them has several air inlet slots 11. The function of the air inlet slots 11 is to allow external gas to enter the gas alarm. The air inlet slots 11 on each side wall are in a grid pattern, and the length of the air inlet slots 11 is about half the width of the side wall. The air inlet slots 11 on the two long walls are distributed on the side closer to the short wall, accounting for about one-third of the length of the long wall. The air inlet slots 11 on the short walls are evenly distributed along their own length. Each of the two long walls of the outer casing 1 has several light-transmitting slots 15, which improve the overall harmony and decoration of the outer casing 1. The inner wall thickness of the decorative light-transmitting slots 15 is relatively thin. When the indicator light at the corresponding position is lit, light can pass through the decorative light-transmitting slots 15 to indicate other indicator lights of the alarm, or to achieve a decorative effect. The light-transmitting groove 15 is also a grid type, located in the middle of the long wall, away from the air intake groove 11.

[0041] Reference Figure 1On the panel of the outer casing 1, near the air inlet slot 11, two buttons 131, a buzzer hole 132, and several LED indicator holes 133 are arranged horizontally in the middle. The buttons 131 are used to control the activation and deactivation of the linkage device and adjust the parameters of the gas alarm. The buzzer hole 132 is the sound outlet for a buzzer or horn; when a gas leak is detected, the buzzer or horn sounds an alarm. The LED indicator lights flash through the LED indicator holes 133, displaying various status indicators of the gas alarm. This also allows people with hearing impairments to be aware of a gas leak through the flashing LED indicators. A data interface 135 is also provided on the panel of the outer casing 1, located on the side of the LED indicator holes 133 near the air inlet slot 11, for reading historical data.

[0042] Reference Figure 1 The outer casing 1 has a PVC film 13 attached to its panel to cover the buttons 131, buzzer hole 132, data interface 135, and LED indicator hole 133, thus isolating it from the outside and improving its protection level. The PVC film 13 is translucent, allowing the lights of the buttons 131 and LED indicator to be seen. When data needs to be read, part of the PVC film 13 can be peeled off to expose the historical data reading interface 135, allowing data to be read without opening the outer casing 1, making operation convenient. A waterproof and breathable membrane 134 is also attached to the outside of the buzzer hole 132, located between the PVC film 13 and the panel. The PVC film 13 does not allow sound to pass through, so an opening is needed at the buzzer hole 132. However, water can easily pass through the PVC film after an opening, so a waterproof and breathable membrane is installed at the bottom of the PVC film to prevent water from entering the buzzer. The waterproof and breathable membrane 134 ensures that the sound from the buzzer or speaker can be transmitted normally, while preventing water and dust from entering the buzzer hole 132.

[0043] Reference Figure 1 and 2 The outer casing 1 has two short walls with wiring harness ports 14. One short wall with an air inlet groove 11 has one wiring harness port 14, and the other short wall has two wiring harness ports 14. The wiring harness ports 14 are used to connect the wiring harness inside the casing to the outside. A rubber shell 141 is installed inside each wiring harness port 14, sandwiched between the mounting plate 2 and the outer casing 1. The rubber shell 141 is elastic and can tightly wrap the wires, preventing water from entering through the wiring harness ports 14. The rubber shell 141 can also be replaced with a silicone shell or similar material with sealing properties.

[0044] Reference Figure 3A number of mounting brackets 23 are fixedly provided on the side of the mounting plate 2 away from the circuit board and away from the protective cover 4. The mounting brackets 23 are used to fix the gas alarm. The mounting brackets 23 are located near the light-transmitting groove 15. The mounting brackets 23 are right-angled folded plates, and the mounting components are hung on the mounting components for installation. The mounting brackets are easy to install and remove.

[0045] Reference Figure 1 The circuit board 3 is located between the outer casing 1 and the mounting plate 2. This structure facilitates assembly and subsequent maintenance, and provides a certain protective space for the circuit board 3. The outer casing 1 has several threaded post holes, and the circuit board 3 and the mounting plate 2 have corresponding holes. By placing the circuit board 3 on the threaded post holes and inserting the mounting plate 2 into the outer casing 1, the three are fastened together with bolts.

[0046] Reference Figure 1 Several sensors 31 and other components are fixedly mounted on the end of the circuit board 3 away from the mounting plate 2. The other components include buzzers or horns, LED indicators, data connectors, and other devices required for the alarm. The sensors 31 are located near the air intake slot 11, and the other components are located near the light transmission slot 15.

[0047] Reference Figure 1 and Figure 4 The sensor 31 is covered with a protective cover 4, which is located at the end of the circuit board 3 away from the mounting plate 2, and is detachably connected to the circuit board 3. Several locking blocks 44 are fixed circumferentially at the end of the protective cover 4 near the circuit board 3. Several slots 32 are formed on the circuit board 3. A third chamfer 441 is formed at the edge of the locking blocks 44 near the mounting plate 2 and away from the sensor 31. After the third chamfer 441 abuts against the slot 32, it causes the locking blocks 44 to bend, allowing them to pass through the circuit board 3. The right-angled side corresponding to the third chamfer 441 abuts against the end face of the circuit board 3 near the mounting plate 2, enabling quick and easy installation of the protective cover 4.

[0048] Reference Figure 1 and Figure 4A retaining ring 42 is fixed to the outer wall of the protective cover 4. The outer wall of the retaining ring 42 abuts against the inner wall of the outer shell 1. The retaining ring 42 is located between the air inlet groove 11 and the light transmission groove 15. The retaining ring 42 and the protective cover 4 work together to divide the space inside the outer shell 1 into two parts: the part outside the protective cover 4 contains other components except for the sensor 31. The space formed by the assembly of the outer shell 1, mounting plate 2, protective cover 4, and retaining ring 42 is in a closed state, preventing other components from communicating with the outside world, thus providing good sealing protection; the part inside the protective cover 4 contains the sensor 31. Two air inlets 41 are opened at the end of the protective cover 4 away from the circuit board 3, corresponding to two gas chambers respectively. A partition 43 is provided inside the protective cover 4, which divides the inside of the protective cover 4 into two gas chambers, allowing two sensors 31 for different gases, such as methane and carbon monoxide, to be installed independently, realizing dual gas detection. In other embodiments, three or more air inlets 41 can also be provided, with a partition 43 between each pair of adjacent air inlets 41, corresponding to the installation of more sensors 31 and the detection of more types of gases. The partition 43 and the protective cover 4 can be detachably connected by plugging and unplugging. The inner wall of the protective cover 4 has a sliding groove, in which the partition 43 is inserted. By removing the partition 43 from the protective cover 4, the space inside the air chamber of the protective cover 4 is increased, allowing for the placement of larger or irregularly shaped sensors 31, such as the new TDLAS laser sensor 31 or the NDIR infrared sensor 31. This flexibly adapts to the installation requirements of different types of sensors 31, enhancing the versatility and compatibility of the gas alarm.

[0049] Reference Figure 2 The inner wall of the outer shell 1 is fixed with several support columns 12 that correspond one-to-one with the air inlet slots 11. The size of the support column 12 is not smaller than the size of the air inlet slot 11, and can completely block the air inlet slot 11. The baffle ring 42 is located between the support column 12 and the circuit board 3, which can prevent the inside of the outer shell 1 from being directly connected to the outside. Substances entering the outer shell 1 from the air inlet slot 11 need to change direction before they can enter the inside of the outer shell 1.

[0050] Reference Figure 1 Driven by natural diffusion, the gas expands through the air inlet 11 to the air inlet of the inner protective cover 4, and then diffuses into the interior of the sensor 31. Due to the slow movement of the gas and the characteristics of natural diffusion, its direction of movement can be continuously changed before entering the interior of the sensor 31. However, for splashing water, smoke, dust particles, etc., due to their mass, their kinetic energy is greatly reduced by gravity when their direction of movement is obstructed, preventing them from entering the sensor 31 cavity through multiple obstructions, thus achieving high protection. Even if water enters the interior through the air inlet 11 (but not yet into the interior of the protective cover 4), it can flow out through the lowest air inlet 11 without water accumulation.

[0051] Reference Figure 1The protective cover 4 also has a waterproof and breathable membrane 134 fixed to its outer wall, which has an air inlet 41. This membrane covers the air inlet 41 and further prevents fine dust from entering the interior of the protective cover 4 in areas with poor air quality. It is also easy to attach and replace, further improving the protection level of the gas alarm. The waterproof and breathable membrane 134 on the protective cover 4 is typically made of polymer material with a microporous structure, allowing gas to pass through while blocking water and dust. In areas with poor air quality, the waterproof and breathable membrane 134 further prevents fine dust from entering, further improving the protection level. Moreover, because the breathable membrane is attached to the outer surface of the protective cover 4, attachment and replacement are simple and easy.

[0052] Reference Figure 2 The inner side of one end of the opening of the outer shell 1 is provided with a mounting ring groove 16. The mounting plate 2 is embedded in the mounting ring groove 16. The end face of the mounting plate 2 abuts against the corresponding end face of the mounting ring groove 16 to achieve a sealing effect. An adhesive strip can also be installed between the mounting plate 2 and the mounting ring groove 16 to further improve its waterproof performance.

[0053] Reference Figure 1 and Figure 5 The inner wall of the outer casing 1 is fixed with several first limiting blocks 17. The end of the mounting plate 2 near the circuit board 3 is fixed with several second limiting blocks 21 corresponding to the limiting blocks. The first limiting blocks 17 have a first chamfer 171 at the edge away from the mounting ring groove 16 and the circuit board 3, and the second limiting blocks 21 have a second chamfer 211 at the edge near the mounting ring groove 16 and the circuit board 3. The outer casing 1 and the mounting plate 2 are detachably connected through the mutual cooperation of the first limiting blocks 17 and the second limiting blocks 211. During installation, the first chamfer 171 and the second chamfer 211 abut against each other, causing the first limiting blocks 17 and the second limiting blocks 21 to bend and press against each other, thus allowing the second limiting blocks 21 to enter the outer casing 1. Simultaneously, the mounting plate 2 fits into the mounting ring groove 16, and the two right-angled surfaces of the first limiting blocks 17 and the second limiting blocks 21 fit together, achieving rapid assembly between the mounting plate 2 and the casing.

[0054] The implementation principle of a gas alarm with improved protection level according to an embodiment of this application is as follows: the outer shell 1 and the mounting plate 2 are detachably connected for easy assembly and maintenance; the circuit board 3 is located between the outer shell 1 and the mounting plate 2 and is protected; the protective cover 4 separates other components from the sensor 31, keeping other components in a closed state and preventing external invasion; the sensor 31 is located inside the protective cover 4 and can work normally; the air inlet 41 facilitates the entry of gas into the sensor 31; the air inlet groove 11 facilitates the entry of gas into the interior of the outer shell 1; the setting of the support column 12 and the retaining ring 42 creates a multi-turn effect between the protective cover 4 and the outer shell 1, blocking splashing water, smoke, dust particles from entering the sensor 31 cavity, improving the waterproof and dustproof level of the gas alarm, making it applicable to places with harsh environments. At the same time, the solution is simple and feasible, low in cost, easy to manufacture, and simple to produce.

[0055] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A gas alarm with improved protection level, characterized in that: The device includes a housing (1), a mounting plate (2), and a circuit board (3). The housing (1) and the mounting plate (2) are detachably connected. The circuit board (3) is located between the housing (1) and the mounting plate (2). Several sensors (31) and a protective cover (4) are fixedly mounted on the end of the circuit board (3) away from the mounting plate (2). The protective cover (4) is located on one side of the circuit board (3). The sensors (31) are located inside the protective cover (4). Several sensors are opened on the end of the protective cover (4) away from the circuit board (3). Each of the three end faces of the outer shell (1) near the protective cover (4) and abutting the mounting plate (2) has an air inlet (41) corresponding to the sensor (31). Each of the three end faces of the outer shell (1) near the protective cover (4) has an air inlet groove (11). Each of the three end faces of the outer shell (1) has a support column (12) corresponding to the air inlet groove (11). Each of the three end faces of the protective cover (4) has a retaining ring (42). The outer wall of the retaining ring (42) abuts against the inner wall of the outer shell (1). The retaining ring (42) is located between the support column (12) and the circuit board (3).

2. A gas alarm with improved protection level according to claim 1, characterized in that: The outer casing (1) has a button (131) at one end near the air inlet (41) and has a buzzer hole (132) and several LED indicator holes (133). The outer wall of the outer casing (1) is fixed with a PVC film (13) for covering the button (131), buzzer hole (132) and LED indicator holes (133). A waterproof and breathable membrane (134) is provided between the buzzer hole (132) and the PVC film (13). The two opposite ends of the outer casing (1) have wire harness ports (14). A rubber shell (141) is provided inside the wire harness port (14). The rubber shell (141) is sandwiched between the mounting plate (2) and the outer casing (1).

3. A gas alarm with improved protection level according to claim 1, characterized in that: The protective cover (4) has a partition (43) between two adjacent air inlets (41) inside, which is used to isolate the two adjacent air inlets (41) and the sensor (31).

4. A gas alarm with improved protection level according to claim 3, characterized in that: The partition (43) and the protective cover (4) are detachably connected.

5. A gas alarm with improved protection level according to claim 1, characterized in that: The outer wall of the outer shell (1) away from the air inlet slot (11) has a light-transmitting slot (15).

6. A gas alarm with improved protection level according to claim 1, characterized in that: The protective cover (4) also has a waterproof and breathable membrane (134) fixed on its outer wall with an air inlet (41).

7. A gas alarm with improved protection level according to claim 1, characterized in that: The inner side of the outer shell (1) near the mounting plate (2) is provided with a mounting ring groove (16). The end face of the mounting plate (2) near the circuit board (3) abuts against the end face of the mounting ring groove (16). A number of first limiting blocks (17) are fixed on the inner wall of the outer shell (1). A number of second limiting blocks (21) corresponding to the limiting blocks are fixed on the end of the mounting plate (2) near the circuit board (3). A first chamfer (171) is provided on the edge of the first limiting block (17) away from the mounting ring groove (16) and the circuit board (3). A second chamfer (211) is provided on the edge of the second limiting block (21) near the mounting ring groove (16) and the circuit board (3).

8. A gas alarm with improved protection level according to claim 1, characterized in that: The protective cover (4) has several locking blocks (44) fixed around one end near the circuit board (3). Several slots (32) are provided on the circuit board (3). The locking blocks (44) have a third chamfer (441) at the edge near the mounting plate (2) and away from the sensor (31).

9. A gas alarm with improved protection level according to claim 1, characterized in that: The mounting plate (2) has several mounting brackets (23) fixed on the side away from the circuit board and away from the protective cover (4). The mounting brackets (23) are used to fix the gas alarm.

10. A gas alarm with improved protection level according to claim 1, characterized in that: The outer shell (1) has a data interface (135) located inside the PVC mask (13).

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