Portable phase change refrigeration box and wireless monitoring system thereof

Abstract

The invention belongs to the technical field of refrigeration monitoring, and discloses a portable phase change refrigeration box and a wireless monitoring system.The portable phase change refrigeration box comprises a refrigeration box body, phase change layers are arranged on the inner wall and the bottom of the refrigeration box body, an opening and closing mechanism is arranged in an inner cavity of the refrigeration box body, and a sealing cover is installed on the opening and closing mechanism; through cooperation of a first temperature sensor, a second temperature sensor, a third temperature sensor and a wireless radio frequency chip, the first temperature sensor, the second temperature sensor and the third temperature sensor can monitor the temperature change in the refrigeration box body in real time, and a compressor is started for refrigeration according to the temperature change condition; and meanwhile, the wireless radio frequency chip is used for transmitting data to display software of the mobile terminal in a wireless mode, so that a user can conveniently monitor the temperature change in the refrigeration box in real time, the temperature interval can be conveniently adjusted according to different stored foods, and the food storage effect is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of refrigeration monitoring, and in particular relates to a portable phase-change refrigeration box and a wireless monitoring system thereof. Background Art

[0002] Refrigerators and freezers are the most commonly used household appliances for food preservation in people's lives. With the diversification of user needs and the improvement of living standards, people have higher and higher requirements for food preservation. The faster the food cools down during the preservation process, the better the preservation effect; In the prior art, the Chinese utility model with announcement number: CN206750575U discloses a portable phase-change fresh-keeping box, which consists of a plastic box body, an inner box arranged in the box body, and a box cover. The inner box is made of polystyrene board insulation material, and a sealed plate-shaped phase-change material is arranged in the middle between the inner box and the plastic box body. The box body is provided with a box cover, which is connected to the box body through a hinge. A movable handle is arranged on the right side of the box body, and a roller is arranged at the bottom of the box body. During the storage process, due to the latent heat storage of the phase change material, the solid-liquid phase change can absorb or release part of the cold of the refrigeration system, delay the temperature rise of the internal space of the box body, increase the storage time and slow down the temperature rise, and does not require an external power supply, is small in size, and is easy to carry.

[0003] However, the temperature control accuracy in the refrigerator is low and the temperature fluctuates greatly, which can easily cause repeated freezing and thawing of food during the freezing process, and it is inconvenient to monitor the temperature. If the door is not completely closed, the refrigerated food will melt quickly, further affecting the food quality.

[0004] To this end, we propose a portable phase change refrigerator box and its wireless monitoring system to solve the problems existing in the prior art, facilitate real-time follow-up monitoring of the temperature in the refrigerated cavity, and facilitate feedback of the temperature monitoring value to the mobile terminal, thereby facilitating understanding of the status of refrigerated items in the refrigerator, improving the preservation effect of refrigerated food, and ensuring the quality of refrigerated food. Summary of the invention

[0005] The purpose of the present invention is to provide a portable phase change refrigerator box and its wireless monitoring system to solve the problems raised in the above background technology that the temperature control accuracy in the refrigerator is low and the temperature fluctuation is large, which easily leads to repeated freezing and thawing of food during the freezing process, and it is inconvenient to monitor the temperature. If the box door is not completely closed, it will cause the refrigerated food to melt quickly, further affecting the food quality.

[0006] To achieve the above object, the present invention adopts the following technical solutions: A portable phase change refrigerator box comprises a refrigerator box body, wherein the inner wall and the bottom of the refrigerator box body are provided with a phase change layer, the inner cavity of the refrigerator box body is provided with an opening and closing mechanism, a sealing cover is installed on the opening and closing mechanism, and the bottom of the inner cavity of the refrigerator box body is provided with a phase change material net bag for refrigerating objects, wherein the phase change material net bag is filled with multiple groups of metal phase change crystal cells.

[0007] Preferably, a temperature display is provided on one side of the refrigeration box body, a limit frame is provided above the inner wall of the refrigeration box body, and a sealing gasket abutting against the limit frame is provided along the edge of the lower surface of the sealing cover.

[0008] Preferably, a circulating fan is arranged in the bottom cavity of the refrigeration box body, an air outlet end of the circulating fan is communicated with the inner cavity of the refrigeration box body, and a circulating air duct for cold air circulation is arranged in the refrigeration box body.

[0009] Preferably, the opening and closing mechanism includes mounting plates fixedly connected to both sides of the inner wall of the cold storage box body and two groups of flippable flip plates, guide grooves are provided on opposite sides of the two groups of mounting plates, drive shafts are rotatably connected to opposite sides of the two groups of mounting plates, one end of the drive shafts is rotatably connected to a connecting rod, one end of the two groups of connecting rods are rotatably connected to synchronous shafts, both ends of the synchronous shafts are respectively slidably connected in the guide grooves, the lower ends of the two groups of flip plates are respectively rotatably connected to the two ends of the synchronous shafts, and the upper ends of the two groups of flip plates are fixedly connected to the lower surface of the sealing cover.

[0010] Preferably, a sliding shaft slidably connected in a guide groove is fixedly connected to the middle part of the opposite side of the two groups of flip plates, and the guide groove is Y-shaped. Portable carrying handles are provided on both sides of the refrigerated box body adjacent to the temperature display, and protective plates are provided on both sides of the inner cavity of the refrigerated box body. Special-shaped grooves for sliding of the synchronous shaft are provided on the opposite sides of the two groups of protective plates.

[0011] A wireless monitoring system installed in a portable phase-change refrigeration box described above, and also includes a remote monitoring system; The remote monitoring system includes a wireless temperature acquisition module, an alarm analysis module and a power supply module; The wireless temperature acquisition module includes a first temperature sensor, a second temperature sensor, a third temperature sensor and a microprocessor, wherein the microprocessor is electrically connected to the first temperature sensor, the second temperature sensor and the third temperature sensor respectively, and the microprocessor is electrically connected to a wireless radio frequency chip; The alarm analysis module includes an opening and closing detection unit, a timing unit and a mobile terminal warning unit for detecting the opening and closing of the sealing cover; The power supply module includes a rechargeable battery for supplying power to the wireless acquisition module and the alarm analysis module.

[0012] Preferably, the first temperature sensor is used to monitor the overall temperature of the refrigerated environment; The second temperature sensor is used to monitor the temperature of the phase change material; The third temperature sensor is used to monitor the temperature of the circulating air outlet; The wireless radio frequency chip is used to send the processed temperature data wirelessly.

[0013] Preferably, the opening and closing detection unit includes a sensor with built-in optical fiber and a reading device, and the reading device is electrically connected to the sensor with built-in optical fiber. By reading the light attenuation value of the optical fiber in the sensor and comparing it with a predefined light attenuation value, the opening and closing state of the sealing cover is determined and recorded in real time. The timing unit includes a timer for monitoring the opening time of the sealing cover.

[0014] Preferably, the mobile terminal warning unit comprises a warning device for warning that the sealing cover is opened but not closed, the warning device is electrically connected to a timer, and the mobile terminal warning unit is connected to a mobile terminal.

[0015] Preferably, the microprocessor detects the temperature change range of the first temperature sensor, and the timer is used to control the alarm to sound when the temperature change difference within the monitoring range does not exceed the set preset range and when the sealing cover is opened and then closed, the alarm emits an intermittent alarm when the monitoring range of the first temperature sensor changes when the sealing cover is not opened, and the alarm emits an urgent alarm when the temperature range monitored by the first temperature sensor exceeds the set preset range.

[0016] The portable phase-change cold storage box and the wireless monitoring system thereof proposed by the present invention have the following advantages compared with the prior art: 1. The present invention uses the design of a wireless temperature acquisition module, and utilizes the cooperation between the first temperature sensor, the second temperature sensor, the third temperature sensor and the wireless radio frequency chip. The first temperature sensor, the second temperature sensor and the third temperature sensor can monitor the temperature change in the cold storage box in real time, and start the compressor to refrigerate according to the temperature change. At the same time, the wireless radio frequency chip is used to transmit the data to the display software of the mobile terminal in a wireless form, so that the user can monitor the temperature change in the cold storage box in real time, thereby facilitating the adjustment of the temperature range according to different stored foods, thereby improving the preservation effect of the food; 2. The present invention cooperates with the refrigeration box body, the phase change layer, the circulating fan and the phase change material net bag. The phase change layer can quickly cool down the temperature inside the refrigeration box body, thereby realizing rapid temperature conduction. At the same time, the circulating fan can facilitate rapid refrigeration of the temperature inside the refrigeration box body. At the same time, the sealing gasket improves the sealing performance, thereby ensuring the refrigeration effect of the refrigeration box body and the quality of food. 3. The cooperation between the refrigerator box body, the portable handle and the opening and closing mechanism of the present invention makes the whole box easy to carry. The connecting rod drives the synchronous shaft to move by rotating the driving shaft, so that the sliding shaft can slide in the guide groove, and the synchronous shaft can be turned around the sliding shaft under the limiting effect of the guide groove, so that the sealing cover can be turned over and the sealing cover can be opened and closed quickly, thereby improving the convenience of use. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the structure of the cold storage box body of the present invention; Figure 2 is a schematic diagram of the phase change layer structure of the present invention; Figure 3 It is a schematic diagram of the sealing cover structure of the present invention; Figure 4 It is a block diagram of the wireless monitoring system of the present invention; Figure 5 It is a flow chart of the temperature change monitoring process of the present invention.

[0018] In the figure: 1. Refrigeration box body; 2. Temperature display; 3. Portable lifting handle; 4. Sealing cover; 5. Opening and closing mechanism; 51. Mounting plate; 52. Guide groove; 53. Driving shaft; 54. Connecting rod; 55. Synchronous shaft; 56. Flip plate; 57. Sliding shaft; 6. Circulating fan; 7. First temperature sensor; 8. Second temperature sensor; 9. Third temperature sensor; 10. Limiting frame; 11. Sealing gasket; 12. Protective plate; 13. Rechargeable battery; 14. Microprocessor; 15. Wireless radio frequency chip; 16. Phase change layer; 17. Phase change material net bag. DETAILED DESCRIPTION

[0019] The following will be combined with the accompanying 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, rather than all the embodiments. The specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0020] The present invention provides Figure 1-5A portable phase change refrigerator box is shown, comprising a refrigerator box body 1, the inner wall and bottom of the refrigerator box body 1 are provided with a phase change layer 16, the inner cavity of the refrigerator box body 1 is provided with an opening and closing mechanism 5, the opening and closing mechanism 5 is installed with a sealing cover 4, and the bottom of the inner cavity of the refrigerator box body 1 is provided with a phase change material net bag 17 for refrigerating objects, the phase change material net bag 17 is filled with multiple groups of metal phase change cells, and the phase change material conducts the phase change latent heat to the food through the metal shell, thereby realizing rapid cooling of the food.

[0021] A temperature display 2 is provided on one side of the refrigeration box body 1, a limit frame 10 is provided above the inner wall of the refrigeration box body 1, and a sealing gasket 11 is provided along the edge of the lower surface of the sealing cover 4 to abut against the limit frame 10. The sealing gasket 11 and the limit frame 10 improve the sealing effect of the refrigeration box body 1, thereby improving the refrigeration effect.

[0022] A circulating fan 6 is arranged in the bottom cavity of the cold storage box body 1, and the air outlet end of the circulating fan 6 is communicated with the inner cavity of the cold storage box body 1. A circulating air duct for cold air circulation is arranged in the cold storage box body 1. By using the circulating fan 6 and cooperating with the design of the circulating air duct, uniform distribution and effective circulation of cold air inside the cold storage box can be achieved, which helps to maintain the stability of the temperature inside the cold storage box, improves the refrigeration effect, and ensures the freshness and quality of stored items.

[0023] The opening and closing mechanism 5 includes a mounting plate 51 fixedly connected to both sides of the inner wall of the cold storage box body 1 and two groups of flippable flip plates 56. The two groups of mounting plates 51 have guide grooves 52 on opposite sides. The two groups of mounting plates 51 have drive shafts 53 rotatably connected to opposite sides. One end of the drive shaft 53 is rotatably connected to a connecting rod 54. One end of the two groups of connecting rods 54 are rotatably connected to synchronous shafts 55. The two ends of the synchronous shaft 55 are respectively slidably connected in the guide grooves 52. The lower ends of the two groups of flip plates 56 are respectively rotatably connected to the two ends of the synchronous shaft 55. The upper ends of the two groups of flip plates 56 are fixedly connected to the lower surface of the sealing cover 4, which is convenient for the rapid opening and closing of the sealing cover 4 and improves the convenience of opening and closing the sealing cover 4.

[0024] A sliding shaft 57 slidably connected to the guide groove 52 is fixedly connected to the middle of the opposite side of the two groups of flip plates 56. The guide groove 52 is arranged in a Y shape. Portable pulling handles 3 are arranged on both sides adjacent to the refrigerated box body 1 and the temperature display 2. Protective plates 12 are arranged on both sides of the inner cavity of the refrigerated box body 1. Special-shaped grooves for sliding of the synchronization shaft 55 are opened on the opposite sides of the two groups of protective plates 12. The special-shaped grooves provide a stable sliding path for the synchronization shaft 55, thereby improving the stability of the refrigerated box body 1.

[0025] A wireless monitoring system installed in a portable phase-change refrigeration box described above, and also includes a remote monitoring system; The remote monitoring system includes a wireless temperature acquisition module, an alarm analysis module and a power supply module; The wireless temperature acquisition module includes a first temperature sensor 7, a second temperature sensor 8, a third temperature sensor 9 and a microprocessor 14. The microprocessor 14 is electrically connected to the first temperature sensor 7, the second temperature sensor 8 and the third temperature sensor 9 respectively. The microprocessor 14 is electrically connected to a wireless radio frequency chip 15. The alarm analysis module includes an opening and closing detection unit, a timing unit and a mobile terminal warning unit for detecting the opening and closing of the sealing cover 4; The power supply module includes a rechargeable battery 13 for supplying power to the wireless acquisition module and the alarm analysis module.

[0026] The first temperature sensor 7 is used to monitor the overall temperature of the refrigeration environment, and is convenient for monitoring the temperature inside the refrigeration box body 1 after the sealing cover 4 is opened and closed; The second temperature sensor 8 is used to monitor the temperature of the phase change material, so as to facilitate real-time monitoring of the temperature of the phase change layer 16; The third temperature sensor 9 is used to monitor the temperature of the circulating air outlet, which is convenient for monitoring the temperature when the cold storage box body 1 is rapidly cooled; The wireless radio frequency chip 15 is used to send the processed temperature data wirelessly. The wireless radio frequency chip 15 is used to conveniently display the detected temperature data through a mobile terminal, so as to facilitate real-time temperature monitoring.

[0027] The opening and closing detection unit includes a sensor with built-in optical fiber and a reading device. The reading device is electrically connected to the sensor with built-in optical fiber. By reading the light attenuation value of the optical fiber in the sensor and comparing it with a predefined light attenuation value, the opening and closing state of the sealing cover 4 is determined and recorded in real time. The timing unit includes a timer for monitoring the opening time of the sealing cover 4. Through the built-in optical fiber sensor and the reading device, the opening and closing state of the sealing cover 4 can be monitored in real time, and a real-time notification can be sent to the user through the mobile terminal warning unit. This real-time monitoring function ensures that the user can understand the status of the cold storage box at any time and take necessary measures in time.

[0028] The mobile terminal warning unit includes an alarm for warning that the sealing cover 4 is not closed after being opened. The alarm is electrically connected to the timer. The mobile terminal warning unit is connected to the mobile terminal. When the sealing cover 4 is opened but not closed in time, the alarm will sound an alarm to remind the user, which helps prevent unauthorized access or accidental opening, thereby protecting the safety of internal items.

[0029] The microprocessor 14 detects the temperature change interval of the first temperature sensor 7. The timer is used to monitor the temperature. When the change in the interval does not exceed the set range and the preset time is reached, the sealing cover 4 is still in the open state. The timer transmits a signal to the microprocessor 14 to control the alarm to sound. When the sealing cover 4 is not opened, the monitoring range of the first temperature sensor 7 changes and the alarm emits an intermittent alarm sound. When the temperature range monitored by the first temperature sensor 7 exceeds the set preset range, the alarm emits an urgent alarm sound. The wireless monitoring system is very easy to use, and users only need to use a mobile terminal to achieve remote monitoring and operation.

[0030] The refrigeration box body 1 is divided into two operating modes for temperature monitoring during use: reminder mode and warning mode. The refrigeration temperature is set to T through the mobile terminal. The specific modes are as follows: 1) When there is no food in the cold storage box body 1, the sealing cover 4 is opened, the fixed time of the timer is t, and the reading device reads the sensor with optical fiber, so as to determine the opening and closing status of the sealing cover 4 according to the read information. When the sealing cover 4 is closed within t, the compressor is turned on, and the circulating fan 6 is not turned on until the temperature T1 of the first temperature sensor 7 = the temperature T2 of the second temperature sensor 8 = the temperature T3 of the third temperature sensor 9 = T, so as to ensure the uniform temperature in the cold storage box body 1; If the sealing cover 4 is not closed within t, the timer transmits a signal to the microprocessor 14, which controls the door closing reminder to sound, thereby reminding the personnel to close the sealing cover 4. After closing the sealing cover 4, repeat the above operation to balance the temperature, which is the reminder mode.

[0031] 2) When food that needs to be kept fresh is placed in the refrigerated box body 1, the sealing cover 4 is opened and then closed, and the compressor is turned on. The specific operating steps are as follows: S1. Place the food to be frozen and fresh-keeping on the upper surface of the phase change layer 16 at the bottom of the refrigeration box body 1, and cover the upper surface of the food with the phase change material net bag 17 so that the phase change metal material therein fits the food. At this time, the compressor of the refrigeration box body 1 is turned on, and the circulating fan 6 is also turned on; S2, at this time T1>T, T2>T, T3>T, close the sealing cover 4 and repeat (1), so that T1=T2=T3=T, to achieve rapid refrigeration of food; 3) When the sealing cover 4 does not need to be opened, the temperatures of T1, T2, and T3 will be detected once every t by the microprocessor 14. When the monitored temperature of T1 is 2-5°C higher or lower than the set temperature within t, the microprocessor 14 transmits a signal to the mobile terminal through the wireless radio frequency chip 15, so that the alarm of the mobile terminal intermittently sounds a reminder. When the monitored temperatures of T1, T2, and T3 exceed the set preset range within t, the microprocessor 14 transmits a signal to the mobile terminal through the wireless radio frequency chip 15, so as to control the alarm of the mobile terminal to sound a rapid sound reminder, which is a warning mode.

[0032] When the sealing cover 4 is opened and closed, it is driven by a hand wheel (not shown in the figure) installed on one group of driving shafts 53. The driving shaft 53 drives the connecting rod 54 to change the position of the synchronous shaft 55. At the same time, under the connection action of the flip plate 56, the sliding shaft 57 slides in the guide groove 52. Further, when the sliding shaft 57 is located directly above the guide groove 52, the synchronous shaft 55 flips with the sliding shaft 57 as the axis, so that the flip plate 56 drives the sealing cover 4 to rise and flip at the same time, which is convenient for opening the sealing cover 4 to facilitate the taking and placing of food. After the food is put in, the phase change material net bag 17 is covered on the food, thereby improving the refrigeration effect of the food.

[0033] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A portable phase change cold storage box, characterized in that: The invention comprises a refrigeration box body (1), wherein the inner wall and the bottom of the refrigeration box body (1) are provided with a phase change layer (16), the inner cavity of the refrigeration box body (1) is provided with an opening and closing mechanism (5), a sealing cover (4) is installed on the opening and closing mechanism (5), and the bottom of the inner cavity of the refrigeration box body (1) is provided with a phase change material net bag (17) for refrigerating objects, wherein the phase change material net bag (17) is filled with a plurality of groups of metal phase change crystal cells.

2. A portable phase change cold storage box according to claim 1, characterized in that: A temperature display (2) is provided on one side of the refrigeration box body (1), a limit frame (10) is provided above the inner wall of the refrigeration box body (1), and a sealing gasket (11) is provided along the edge of the lower surface of the sealing cover (4) to abut against the limit frame (10).

3. A portable phase change cold storage box according to claim 2, characterized in that: A circulating fan (6) is arranged in the bottom cavity of the refrigerating box body (1); an air outlet end of the circulating fan (6) is connected to the inner cavity of the refrigerating box body (1); and a circulating air duct for cold air circulation is arranged in the refrigerating box body (1).

4. A portable phase change cold storage box according to claim 3, characterized in that: The opening and closing mechanism (5) comprises a mounting plate (51) fixedly connected to both sides of the inner wall of the cold storage box body (1) and two groups of flippable flip plates (56), the two groups of mounting plates (51) having opposite sides each having a guide groove (52), the two groups of mounting plates (51) having opposite sides each having a drive shaft (53) rotatably connected thereto, one end of the drive shaft (53) being rotatably connected thereto a connecting rod (54), one end of the two groups of connecting rods (54) being rotatably connected thereto a synchronization shaft (55), the two ends of the synchronization shaft (55) being respectively slidably connected in the guide groove (52), the lower ends of the two groups of flip plates (56) being respectively rotatably connected to the two ends of the synchronization shaft (55), and the upper ends of the two groups of flip plates (56) being fixedly connected to the lower surface of the sealing cover (4).

5. A portable phase change cold storage box according to claim 4, characterized in that: A sliding shaft (57) slidably connected in the guide groove (52) is fixedly connected to the middle of the opposite side of the two groups of flip plates (56), and the guide groove (52) is arranged in a Y shape. Portable lifting handles (3) are arranged on both sides of the refrigeration box body (1) adjacent to the temperature display (2). Protective plates (12) are arranged on both sides of the inner cavity of the refrigeration box body (1), and special-shaped grooves for sliding the synchronization shaft (55) are opened on the opposite sides of the two groups of protective plates (12).

6. A wireless monitoring system installed in a portable phase-change refrigeration box according to any one of claims 1 to 5, characterized in that: It also includes a remote monitoring system; The remote monitoring system includes a wireless temperature acquisition module, an alarm analysis module and a power supply module; The wireless temperature acquisition module comprises a first temperature sensor (7), a second temperature sensor (8), a third temperature sensor (9) and a microprocessor (14); the microprocessor (14) is electrically connected to the first temperature sensor (7), the second temperature sensor (8) and the third temperature sensor (9), respectively; and the microprocessor (14) is electrically connected to a wireless radio frequency chip (15); The alarm analysis module comprises an opening and closing detection unit for detecting the opening and closing of the sealing cover (4), a timing unit and a mobile terminal warning unit; The power supply module comprises a rechargeable battery (13) for supplying power to the wireless acquisition module and the alarm analysis module.

7. A wireless monitoring system according to claim 6, characterized in that: The first temperature sensor (7) is used to monitor the overall temperature of the refrigerated environment; The second temperature sensor (8) is used to monitor the temperature of the phase change material; The third temperature sensor (9) is used to monitor the temperature of the circulating air outlet; The wireless radio frequency chip (15) is used to send the processed temperature data wirelessly.

8. A wireless monitoring system according to claim 7, characterized in that: The opening and closing detection unit comprises a sensor with an optical fiber built in and a reading device, wherein the reading device is electrically connected to the sensor with an optical fiber built in, and reads the optical attenuation value of the optical fiber in the sensor and compares it with a predefined optical attenuation value to determine the opening and closing state of the sealing cover (4) and record it in real time, and the timing unit comprises a timer for monitoring the opening time of the sealing cover (4).

9. A wireless monitoring system according to claim 8, characterized in that: The mobile terminal warning unit comprises a warning device for warning that the sealing cover (4) is opened but not closed, the warning device is electrically connected to a timer, and the mobile terminal warning unit is connected to a mobile terminal.

10. A wireless monitoring system according to claim 9, characterized in that: The microprocessor (14) detects the temperature change range of the first temperature sensor (7). The timer is used to control the alarm to sound when the temperature change difference within the monitoring range does not exceed a preset range and when the sealing cover (4) is closed after being opened. When the sealing cover (4) is not opened, the alarm emits an intermittent alarm sound when the monitoring range of the first temperature sensor (7) changes. When the monitoring range of the first temperature sensor (7) exceeds the preset range, the alarm emits an urgent alarm sound.

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