Microwave hot blast stove intelligent control system and microwave hot blast stove

Abstract

The invention provides a microwave hot blast stove intelligent control system which comprises a microwave assembly, a hot blast assembly, a temperature sensor, a humidity sensor, a material identification sensor and an intelligent control module which are installed in a microwave hot blast stove. The intelligent control module is electrically connected with the microwave assembly, the hot air assembly, the temperature sensor, the humidity sensor and the material recognition sensor. According to the intelligent control system of the microwave hot blast stove, materials needing to be heated in the inner box body and a container containing the materials can be recognized through the material recognition sensor, even if a user carelessly puts materials which are not suitable for microwave heating, the system can also automatically forbid a microwave heating mode, the safety performance of the system is improved, and the user experience is improved. And three heating modes of microwave assembly heating, hot air assembly heating or microwave and hot air mixed heating can be intelligently selected according to the materials, and real energy consumption optimization is achieved. The invention further provides the microwave hot blast stove applying the intelligent control system.

Description

Technical Field

[0001] The present invention relates to the technical field of food processing equipment, and in particular to an intelligent control system for a microwave hot air stove and a microwave hot air stove. Background Art

[0002] A hot air stove is a device that heats and cooks food by placing it in a closed space. Existing hot air stoves generally use resistance heating, that is, the heating element is first powered to heat up, part of the heat generated by the heating element is conducted to the air, the other part is radiated to the wall of the gas container, and then part is conducted to the wall of the gas container through the air, and then conducted to the gas through the wall of the gas container, while the other part of the heat radiation is directly conducted to the gas through the wall of the gas container. The heat conducted through the air can only reach the gas after two heat conductions. Therefore, this heating method has a large heat loss, a slow heating speed, and high power consumption. Microwave heating technology uses high-frequency electromagnetic waves with a wavelength of 1 to 3 mm and a frequency of 300 MHz to 300 GHz to heat the material, and uses the electromagnetic wave energy of microwaves to vibrate the water molecules in the material to generate heat. It has the characteristics of high energy utilization efficiency and fast heating speed, and can accurately control the temperature of the heated object to avoid the occurrence of thermal runaway. However, microwave heating has many limitations. Not all materials are suitable for microwave heating. For example: (1) Foods with shells and films. These foods will produce steam during heating. Due to the obstruction of the shell and film, the steam cannot be dissipated, resulting in an increase in internal pressure, which may cause an explosion. (2) Foods with low moisture content and high fat content. These foods are prone to burn when heated, producing harmful substances such as benzopyrene, heterocyclic amines and acrylamide, and there is also a risk of explosion. (3) Foods with extremely low moisture content, high viscosity, and solidified foods are also not suitable for long-term heating in the microwave, otherwise they are prone to explosion; (4) Certain types of ingredients, eggs: Heating eggs in shells in the microwave may cause explosions; grapes: Even two whole grapes put into the microwave will produce sparks or even explode. There are also many containers that are not suitable for microwave heating, for example: (5) Metal containers. Microwaves are reflective and will be reflected back when they hit metal, and cannot penetrate metal containers to heat food. Microwaves will generate sparks with metal containers, and in serious cases, they may even cause fires. (6) Ordinary plastic containers. Common plastic bottles for soda and fast food boxes are generally made of PETE (polyethylene terephthalate) and PS (polystyrene). These two types of plastic products cannot be placed in microwave ovens because high temperatures will cause them to release chemicals that are harmful to the human body. (7) Plastic wrap. Plastic wrap is also plastic, usually LDPE (low-density polyethylene). At high temperatures, LDPE will produce harmful substances, which will precipitate into food and cause damage to the human body.

[0003] There are also reports on microwave hot air furnace related technologies in the prior art. For example, the Chinese patent application with publication number CN105737220A discloses a microwave hot air furnace body, including a microwave oven cavity with a hollow structure inside, the cavity is divided into a main cooking cavity, a top air outlet cavity, a bottom return air cavity, a circulating air duct and a centrifugal air pressure cavity, electric heating elements are arranged in the top air outlet cavity and the bottom return air cavity, a catalytic converter is installed in the circulating air duct near the air pressure cavity, a centrifugal blast device is arranged in the centrifugal air pressure cavity, and a high-frequency microwave generating device is arranged at the top of the top air outlet cavity, and the top air guide plate that allows microwaves and hot air to pass through is used to isolate the top air outlet cavity from the main cooking cavity. The invention integrates high-frequency microwaves and strong convection circulating hot air, and is a hybrid heating method with powerful functions, fast and environmentally friendly. It greatly improves the disadvantages of traditional heating methods such as single function, low efficiency, easy pollution, easy odor, high energy consumption and high operating costs, and is energy-saving, environmentally friendly, efficient and convenient. However, the above schemes and the prior art still generally have the following defects: (1) The intelligence level is low, and the heating mode cannot be intelligently selected according to the material, and the true energy consumption optimization cannot be achieved; (2) The safety performance is poor. When the user accidentally puts materials that are not suitable for microwave heating or the container for loading materials, safety accidents are likely to occur; (3) When using the microwave and hot air mixed heating mode, it is impossible to accurately find the best intervention point for microwave heating, and it is impossible to achieve the best heating strategy for the inside and surface of the material, and it is impossible to optimize the energy consumption. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention proposes an intelligent control system for a microwave hot blast furnace and a microwave hot blast furnace. The intelligent control system can intelligently identify materials and containers in the microwave hot blast furnace, and intelligently select a heating mode according to the materials, so as to achieve true energy consumption optimization; and when using a microwave and hot air mixed heating mode, it can accurately find the best intervention point for microwave heating, realize the best heating strategy for the inside and surface of the material, and achieve energy consumption optimization.

[0005] To realize the above technical solution, the present invention provides an intelligent control system for a microwave hot blast furnace, comprising: a microwave component, a hot blast component, a temperature sensor, a humidity sensor, a material identification sensor and an intelligent control module installed in the microwave hot blast furnace, wherein the intelligent control module is electrically connected to the microwave component, the hot blast component, the temperature sensor, the humidity sensor and the material identification sensor respectively, and the intelligent control system operates in the following manner:

[0006] S1. Identify the material to be heated and the container for loading the material placed in the inner box through the material identification sensor;

[0007] S2. Compare the identified material with the database loaded in the system control device to determine whether the microwave hot air furnace starts microwave component heating, hot air component heating, or microwave and hot air mixed heating; when the microwave component heating mode is selected, the hot air component is turned off, and the microwave generator in the microwave component works to directly heat the material; when the hot air component heating mode is selected, the microwave component is turned off, and the electric heating pipe in the hot air component heats the air, and the heated air is sent into the heating cavity of the inner box through the air uniformity plate by the fan;

[0008] S3. When the system uses the microwave and hot air mixed heating mode, the system first controls the electric heating pipe in the hot air component to heat the air, and then introduces the heated air into the inner box through the fan to heat the surface of the material. When the temperature sensor detects that the surface of the material is heated to the optimal intervention temperature T 1 After that, the system controls the microwave components to intervene, so that the inside of the material is heated quickly, and the temperature inside the material is raised to the target temperature T set by the microwave hot air furnace within the same time as the temperature on the surface of the material. 2 .

[0009] Preferably, in step S2, the material identification sensor is a visual identification sensor. When the material is fed into the inner box, it is visually photographed and identified and compared with a database loaded in the system to quickly analyze the type of the material and the container in which the material is loaded. The most suitable heating mode is comprehensively determined based on the material type and the container in which the material is loaded, and then microwave component heating, hot air component heating, or microwave and hot air mixed heating is started according to the optimal heating mode.

[0010] Preferably, in step S2, the most suitable heating mode is determined in the following manner:

[0011] S21. When any type of material or material container identified by the visual recognition sensor is prohibited from microwave heating, microwave component heating mode and microwave and hot air mixed heating are excluded, and the system can only select hot air component heating mode;

[0012] S22. When the material identified by the visual recognition sensor and the material loading container can both be heated by microwaves, and microwave heating will not affect the taste of the material, the system preferentially selects the microwave component heating mode;

[0013] S23, when the material identified by the visual recognition sensor and the material loading container can both be heated by microwaves, and microwave heating will affect the taste of the material, the system preferentially selects the hot air component heating mode;

[0014] S24. When the material identified by the visual recognition sensor and the container for loading the material can both be heated by microwaves, and the surface and interior of the material need to be heated simultaneously, the system gives priority to hot air and microwave and hot air mixed heating modes.

[0015] Preferably, in step S3, the target temperature T 2 The system determines the material type based on the target temperature T 2 The material surface temperature T when the microwave component is involved can be inferred by the following method: 1 :

[0016] S31. According to Newton's law of cooling, when an object is exposed to hot air, its surface temperature will gradually approach the temperature of the hot air over time. The calculation formula for the change in the surface temperature of the object is as follows:

[0017] T(t)=T 环境 +(T 初始 -T 环境 ) -kt Formula 1

[0018] Where T(t) is the temperature of the material at time t, T 环境 is the temperature of hot air, T 初始 is the initial temperature of the material, k is a positive constant that depends on the properties of the material and the hot air, and t is the drying time;

[0019] S32. A regression equation is established with drying time as an influencing factor. The optimization equation for drying time and process parameters is:

[0020] t=116.59-129X 1 -7.38X 2 -12.13X 3 +8X 1 X 3 -9.75X 2 X 3 +83.83X 1 2 +14.58X 2 2 Formula 2

[0021] In formula 1, t is the temperature T of the material during microwave heating. 1 Rise to target temperature T 2 Drying time, min; X 1 is the microwave temperature control temperature, ℃; X 2 is the drying time per cycle, min; X 3 is the temperature difference, i.e. T 2 -T 1 ,℃;

[0022] S33, microwave temperature control temperature X 1It is selective. For a certain medium or material, the power P absorbed by the medium is proportional to the power frequency f and the square of the electric field strength. The relationship is as follows:

[0023] P=2πε 0 ε'tanδE 2 f Formula 3

[0024] In formula 2, ε 0 is the dielectric constant of vacuum, which is 8.85×10 -12 As / Vm; ε' is the dielectric constant, As / Vm; tanδ is the dielectric tangent loss; E is the electric field strength; f is the microwave power frequency;

[0025] S34. The system determines the power P absorbed by the medium according to the identified material type, and then accurately calculates the electric field strength E according to Formula 3, and then calculates the microwave temperature control temperature X according to the determined electric field strength E and drying time. 1 Then the system calculates the temperature difference X in reverse according to formula 2 3 , since the target temperature T 2 Known, the material surface temperature T can be accurately calculated 1 , this is the best time to intervene with microwave heating.

[0026] The present invention also provides a microwave hot air stove, comprising the above-mentioned microwave hot air stove intelligent control system, and also comprising an outer shell, wherein an inner box is installed in the outer shell, a microwave component is installed on the top of the inner box, a hot air component is installed on the back of the inner box, a temperature sensor, a humidity sensor and a material identification sensor are all installed in the inner box, and an intelligent control module is installed in the cavity between the outer shell and the inner box.

[0027] Preferably, the microwave assembly includes a mounting plate arranged on the top of the inner box body, a microwave generating chamber is installed on the mounting plate, a microwave generator is installed in the microwave generating chamber and is connected to the inner box body through a guide cover, a microwave heat dissipation groove is arranged at the rear of the microwave generating chamber, and a power contactor and a frequency converter are respectively installed on the left and right sides of the microwave generator on the mounting plate, and the power contactor and the frequency converter are respectively electrically connected to the microwave generator.

[0028] Preferably, the hot air assembly includes a rear sealing plate arranged at the rear of the inner box body, the fan is installed on the rear sealing plate, and the blades at the front end of the fan are located in a cavity formed by the rear sealing plate, the inner box body, and a partition installed in the inner box body, the electric heating tube is installed in a ring shape on the outside of the fan blades, and a uniform wind hole plate connected to the inner box body is arranged above the partition.

[0029] Preferably, a door assembly is installed on the front side of the outer shell, and the door assembly includes a door body and a handle. The door body is installed on the front side of the outer shell, and the handle is installed on the door body. In actual use, the door body can be opened and closed by the handle.

[0030] Preferably, a control panel is installed on the front side of the outer shell, and the control panel includes a touch screen and a power on / off button. The touch screen is installed on the top of the front side of the outer shell, and the power on / off button is installed on one side of the touch screen.

[0031] Preferably, a heat dissipation assembly is installed on the bottom plate of the outer shell and is located below the inner box body. The heat dissipation assembly includes a cooling fan mounting bracket and a cooling fan, wherein the cooling fan mounting bracket is fixed on the bottom plate, the cooling fan is installed on the cooling fan mounting bracket and is located below the inner box body, and a heat dissipation hole is arranged on the bottom plate opposite to the cooling fan.

[0032] The beneficial effects of the microwave hot blast stove intelligent control system and the microwave hot blast stove provided by the invention are:

[0033] (1) The intelligent control system of the microwave hot air furnace has a high degree of intelligence. It can identify the materials to be heated and the containers for loading the materials in the inner box through the material identification sensor. Even if the user accidentally puts in materials that are not suitable for microwave heating or the containers for loading the materials, the system can automatically prohibit the microwave heating mode to improve the safety performance of the system. In addition, it can intelligently select three heating modes according to the materials, namely, microwave component heating, hot air component heating, or microwave and hot air mixed heating, so as to achieve true energy consumption optimization;

[0034] (2) When using the microwave and hot air mixed heating mode, the intelligent control system of the microwave hot air furnace can accurately find the best intervention point for microwave heating, realize the best heating strategy for the inside and surface of the material, and optimize energy consumption.

[0035] (3) The microwave hot air furnace has a simple structure, reasonable design, and high intelligence. In actual operation, it can realize automatic selection of three heating modes, namely, microwave component heating, hot air component heating, and microwave and hot air mixed heating. It can realize the effective integration of resistance heating and microwave heating in the hot air furnace and improve thermal efficiency and uniformity of air distribution. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic diagram of the three-dimensional structure of the microwave hot air furnace in the present invention.

[0037] Figure 2 It is a front view of the internal assembly structure of the microwave hot air oven in the present invention.

[0038] Figure 3It is a rear view of the internal assembly structure of the microwave hot air oven in the present invention.

[0039] Figure 4 It is a schematic diagram of the internal three-dimensional structure of the present invention.

[0040] In the figure: 1. outer shell; 2. door assembly; 21. door body; 22. handle; 3. control panel; 31. touch screen; 32. power on / off button; 4. inner box; 5. microwave assembly; 51. mounting plate; 52. microwave generating chamber; 53. microwave generator; 54. microwave heat sink; 55. power contactor; 56. inverter; 6. hot air assembly; 61. rear sealing plate; 62. fan; 63. electric heating pipe; 64. uniform air hole plate; 65. partition; 7. heat dissipation assembly; 71. cooling fan mounting bracket; 72. cooling fan; 8. intelligent control module; 9. temperature sensor; 10. material identification sensor; 11. humidity sensor. DETAILED DESCRIPTION

[0041] 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. All other embodiments obtained by ordinary persons in the art without creative work are within the scope of protection of the present invention.

[0042] Embodiment 1: A microwave hot air oven.

[0043] Reference Figures 1 to 4 As shown, a microwave hot air oven comprises: an outer shell 1, an inner box 4 is installed in the outer shell 1, a door assembly 2 is installed on the front side of the outer shell 1, and the door assembly 2 comprises a door body 21 and a handle 22, the door body 21 is installed on the front side of the outer shell 1, and the handle 22 is installed on the door body 21. In actual use, the door body 21 can be opened and closed by the handle 22. A control panel 3 is installed on the front side of the outer shell 1, and the control panel 3 comprises a touch display screen 31 and a power on / off button 32, the touch display screen 31 is installed on the top of the front side of the outer shell 1, and the power on / off button 32 is installed on one side of the touch display screen 31. In actual work, the overall opening and closing of the device can be controlled by the power on / off button 32, and the working parameters can be adjusted by the touch display screen 31. A heat dissipation assembly 7 is installed on the bottom plate of the outer shell 1 below the inner box 4, and the heat dissipation assembly 7 includes a heat dissipation fan mounting bracket 71 and a heat dissipation fan 72, wherein the heat dissipation fan mounting bracket 71 is fixed on the bottom plate of the outer shell 1, and the heat dissipation fan 72 is mounted on the heat dissipation fan mounting bracket 71 and is located below the inner box 4, and heat dissipation holes are provided on the bottom plate at a position opposite to the heat dissipation fan 72. In actual operation, the heat dissipation of the inner box 4 can be achieved through the heat dissipation fan 72.

[0044] The microwave assembly 5 is installed on the top of the inner box 4, the hot air assembly 6 is installed on the back of the inner box 4, the temperature sensor 9, the humidity sensor 11 and the material identification sensor 10 are all installed in the inner box 4, and the intelligent control module 8 is installed in the cavity between the outer shell 1 and the inner box 4. The microwave assembly 5 includes a mounting plate 51 arranged on the top of the inner box 4, a microwave generating chamber 52 is installed on the mounting plate 51, a microwave generator 53 is installed in the microwave generating chamber 52 and is connected to the inner box 4 through a flow guide cover, a microwave heat dissipation slot 54 is arranged behind the microwave generating chamber 52, and a power contactor 55 and a frequency converter 56 are respectively installed on the mounting plate 51 on the left and right sides of the microwave generator 53, and the power contactor 55 and the frequency converter 56 are respectively electrically connected to the microwave generator 53. In actual operation, when the microwave generator 53 is started, the high-intensity magnetic field generated can directly act on the material placed in the inner box 4. The electromagnetic wave energy makes the water molecules in the material vibrate to generate heat, thereby heating the material from the inside out, and the heating speed is fast and the energy consumption is low.

[0045] The hot air assembly 6 includes a rear sealing plate 61 disposed at the rear of the inner box 4, a fan 62 is mounted on the rear sealing plate 61, and the fan blades at the front end of the fan 62 are located in a cavity enclosed by the rear sealing plate 61, the inner box 4, and a partition 65 installed in the inner box 4, and the electric heating pipe 63 is installed in a ring shape on the outside of the fan blades of the fan 62, and a uniform wind hole plate 64 connected to the inner box 4 is arranged above the partition 65. In actual operation, the electric heating pipe 63 heats the air, and the heated air is sent into the heating cavity of the inner box 4 through the uniform wind hole plate 64 by the fan 62.

[0046] The intelligent control system of the microwave hot air furnace has a simple structure and a reasonable design. In actual operation, the microwave hot air furnace can realize three heating modes through the intelligent control module 8, namely: heating by the microwave component 5, heating by the hot air component 6, and microwave and hot air mixed heating. When the microwave component 5 heating mode is selected, the hot air component 6 is turned off. When the microwave generator 53 is started, the high-intensity magnetic field generated can directly act on the material placed in the inner box 4. The electromagnetic wave energy makes the water molecules in the material vibrate to generate heat, thereby heating the material from the inside to the outside, and the heating speed is fast and the energy consumption is low. When the hot air component 6 heating mode is selected, the microwave component 5 is turned off, the electric heating pipe 63 in the hot air component 6 heats the air, and the heated air is sent into the heating cavity of the inner box 4 through the air uniformity plate 64 by the fan 62. When microwave and hot air mixed heating is selected, the system first controls the electric heating tube 63 in the hot air component 6 to heat the air, and then introduces the heated air into the inner box 4 through the fan 62 to heat the surface of the material. When the temperature sensor 9 detects that the surface of the material is heated to the optimal intervention temperature, the system controls the microwave component 5 to intervene, so that the inside of the material is heated quickly, and the temperature of the heated inside the material is raised to the target temperature set by the microwave hot air furnace within the same time as the temperature of the material surface, thereby realizing the effective fusion of resistance heating and microwave heating in the hot air furnace, improving thermal efficiency and uniformity of air distribution, and optimizing energy consumption.

[0047] Embodiment 2: A microwave hot air furnace intelligent control system.

[0048] Reference Figures 1 to 4 As shown, a microwave hot blast furnace intelligent control system comprises: a microwave component 5, a hot blast component 6, a temperature sensor 9, a humidity sensor 11, a material identification sensor 10 and an intelligent control module 8 installed in the microwave hot blast furnace as described in Example 1, wherein the intelligent control module 8 is electrically connected to the microwave component 5, the hot blast component 6, the temperature sensor 9, the humidity sensor 11 and the material identification sensor 10, respectively, and the intelligent control system operates as follows:

[0049] 1. Identification of materials and containers

[0050] The material identification sensor is used to identify the materials to be heated and the containers for loading the materials placed in the inner box. The purpose of using the material identification sensor to identify the materials and the containers for loading the materials is mainly to quickly determine whether the materials to be heated and the containers for loading the materials can be heated in a microwave, or which heating method is more suitable for the materials, so as to achieve the fastest and least energy consumption without affecting the taste of the food.

[0051] (II) Database comparison and intelligent selection of heating methods

[0052] The identified material is compared with the database loaded in the system control device. In this embodiment, the material identification sensor is a visual identification sensor. When the material is sent into the inner box, it is compared with the database loaded in the system after visual photography and identification, and the type of the material and the container for loading the material is quickly analyzed. The most suitable heating mode is comprehensively judged according to the material type and the container for loading the material, and then the microwave component heating, hot air component heating or microwave and hot air mixed heating is started according to the best heating mode. When the microwave component heating mode is selected, the hot air component is turned off, and the microwave generator in the microwave component works to directly heat the material; when the hot air component heating mode is selected, the microwave component is turned off, and the electric heating pipe in the hot air component heats the air, and the heated air is sent to the heating cavity of the inner box through the wind uniformity plate by the fan.

[0053] The most suitable heating mode is determined in the following ways:

[0054] (1) When the visual recognition sensor identifies that any of the materials or material containers are prohibited from microwave heating, the microwave component heating mode and microwave and hot air mixed heating are excluded, and the system can only select the hot air component heating mode;

[0055] (2) When the material identified by the visual recognition sensor and the container in which the material is loaded can both be heated by microwaves, and microwave heating will not affect the taste of the material, the system will give priority to the microwave component heating mode;

[0056] (3) When the material identified by the visual recognition sensor and the material loading container can both be heated by microwaves, and microwave heating will affect the taste of the material, the system will give priority to the hot air component heating mode;

[0057] (4) When the material identified by the visual recognition sensor and the container in which the material is loaded can both be heated by microwaves, and the surface and interior of the material need to be heated simultaneously, the system gives priority to the hot air and microwave and hot air mixed heating modes.

[0058] In this embodiment, the database loaded into the system contains a large amount of material and container data. After the visual recognition sensor uploads photos of the materials and containers, the system will automatically compare and analyze the correct material and container types, providing an important basis for subsequent heating types, and can prevent the occurrence of mismatched materials when using microwave heating, greatly improving the safety of the system.

[0059] (III) Selection of the best intervention point and optimization of energy consumption

[0060] In actual operation, microwave heating has the lowest energy consumption, while hot air heating has the highest energy consumption. However, in the actual heating process, microwave heating transfers heat from the inside to the outside, and the heating speed is fast, while hot air heating transfers heat from the outside to the inside, and the heat transfer speed is relatively slow. For some materials, both the inside and the outside need to be heated at the same time to achieve the best heating effect and the best taste. However, since the rate of microwave heating is obviously faster than that of hot air heating, when turning on the microwave and hot air mixed heating mode, hot air heating needs to be turned on first. When the hot air heats the surface of the material to a certain temperature, microwave heating is started again, and then the internal heating and surface synchronous heating are completed in the same time. This can not only achieve the lowest energy consumption, but also ensure the best taste of the heated material.

[0061] Therefore, when the system uses the microwave and hot air mixed heating mode, the system first controls the electric heating pipe in the hot air component to heat the air, and then introduces the heated air into the inner box through the fan to heat the surface of the material. When the temperature sensor detects that the surface of the material is heated to the optimal intervention temperature T 1 After that, the system controls the microwave components to intervene, so that the inside of the material is heated quickly, and the temperature inside the material is raised to the target temperature T set by the microwave hot air furnace within the same time as the temperature on the surface of the material. 2 .

[0062] Target temperature T 2 The system determines the material type based on the target temperature T 2 The material surface temperature T when the microwave component is involved can be inferred by the following method: 1 :

[0063] (a) According to Newton's law of cooling, when an object is exposed to hot air, its surface temperature will gradually approach the temperature of the hot air over time. The formula for calculating the change in the surface temperature of the object is as follows:

[0064] T(t)=T 环境 +(T 初始 -T 环境 ) -kt Formula 1

[0065] Where T(t) is the temperature of the material at time t, T 环境 is the temperature of hot air, T 初始 is the initial temperature of the material, k is a positive constant that depends on the properties of the material and the hot air, and t is the drying time;

[0066] (b) A regression equation was established with drying time as the influencing factor, and the optimization equation for drying time and process parameters was:

[0067] t=116.59-129X1 -7.38X 2 -12.13X 3 +8X 1 X 3 -9.75X 2 X 3 +83.83X 1 2 +14.58X 2 2 Formula 2

[0068] In formula 1, t is the temperature T of the material during microwave heating. 1 Rise to target temperature T 2 Drying time, min; X 1 is the microwave temperature control temperature, ℃; X 2 is the drying time per cycle, min; X 3 is the temperature difference, i.e. T 2 -T 1 ,℃;

[0069] (c) Microwave temperature control temperature X 1 It is selective. For a certain medium or material, the power P absorbed by the medium is proportional to the power frequency f and the square of the electric field strength. The relationship is as follows:

[0070] P=2πε 0 ε'tanδE 2 f Formula 3

[0071] In formula 2, ε 0 is the dielectric constant of vacuum, which is 8.85×10 -12 As / Vm; ε' is the dielectric constant, As / Vm; tanδ is the dielectric tangent loss; E is the electric field strength; f is the microwave power frequency;

[0072] (d) The system determines the power P absorbed by the medium based on the identified material type, and then accurately calculates the electric field strength E according to Formula 3. The microwave temperature control temperature X is then calculated based on the determined electric field strength E and drying time. 1 Then the system calculates the temperature difference X in reverse according to formula 2 3 , since the target temperature T 2 Known, the material surface temperature T can be accurately calculated 1 , this is the best time to intervene with microwave heating.

[0073] The intelligent control system of the microwave hot air furnace is highly intelligent. It can identify the materials that need to be heated and the containers for loading materials in the inner box through the material identification sensor. Even if the user accidentally puts materials that are not suitable for microwave heating or the containers for loading materials, the system can automatically prohibit the microwave heating mode to improve the safety performance of the system. It can also intelligently select three heating modes, namely microwave component heating, hot air component heating, or microwave and hot air mixed heating, according to the materials, to achieve true energy consumption optimization. Moreover, when using the microwave and hot air mixed heating mode, the intelligent control system of the microwave hot air furnace can accurately find the best intervention point for microwave heating, realize the best heating strategy for the inside and surface of the material, and optimize energy consumption.

[0074] The above description is only a preferred embodiment of the present invention, but the present invention should not be limited to the contents disclosed in the embodiment and the drawings, so any equivalent or modification completed without departing from the spirit disclosed in the present invention shall fall within the scope of protection of the present invention.

Claims

1. A microwave hot air furnace intelligent control system, characterized in that include: The microwave assembly, hot air assembly, temperature sensor, humidity sensor, material identification sensor and intelligent control module installed in the microwave hot air oven are electrically connected to the microwave assembly, hot air assembly, temperature sensor, humidity sensor and material identification sensor respectively. The intelligent control system operates as follows: S1. Identify the material to be heated and the container for loading the material placed in the inner box through the material identification sensor; S2. Compare the identified material with the database loaded in the system control device to determine whether the microwave hot air furnace starts microwave component heating, hot air component heating, or microwave and hot air mixed heating; when the microwave component heating mode is selected, the hot air component is turned off, and the microwave generator in the microwave component works to directly heat the material; when the hot air component heating mode is selected, the microwave component is turned off, and the electric heating pipe in the hot air component heats the air, and the heated air is sent into the heating cavity of the inner box through the air uniformity plate by the fan; S3. When the system selects the microwave and hot air mixed heating mode, the microwave component and the hot air component work at the same time. The system first controls the electric heating tube in the hot air component to heat the air, and then introduces the heated air into the inner box through the fan to heat the surface of the material. When the temperature sensor detects that the surface of the material is heated to the optimal intervention temperature T1, the system controls the microwave component to intervene, so that the inside of the material is heated quickly, and the temperature inside the material is raised to the target temperature T2 set by the microwave hot air furnace within the same time as the temperature of the material surface.

2. The microwave hot blast stove intelligent control system according to claim 1, characterized in that: In step S2, the material identification sensor is a visual identification sensor. When the material is fed into the inner box, it is visually photographed and identified and compared with the database loaded in the system to quickly analyze the type of material and the container for loading the material. The most suitable heating mode is comprehensively judged based on the material type and the container for loading the material, and then microwave component heating, hot air component heating, or microwave and hot air mixed heating are started according to the optimal heating mode.

3. The microwave hot blast stove intelligent control system according to claim 2, characterized in that: In step S2, the most suitable heating mode is determined in the following manner: S21. When any type of material or material container identified by the visual recognition sensor is prohibited from microwave heating, microwave component heating mode and microwave and hot air mixed heating are excluded, and the system can only select hot air component heating mode; S22. When the material identified by the visual recognition sensor and the material loading container can both be heated by microwaves, and microwave heating will not affect the taste of the material, the system preferentially selects the microwave component heating mode; S23, when the material identified by the visual recognition sensor and the material loading container can both be heated by microwaves, and microwave heating will affect the taste of the material, the system preferentially selects the hot air component heating mode; S24. When the material identified by the visual recognition sensor and the container for loading the material can both be heated by microwaves, and the surface and interior of the material need to be heated simultaneously, the system gives priority to hot air and microwave and hot air mixed heating modes.

4. The microwave hot blast stove intelligent control system according to claim 1, characterized in that: In step S3, the target temperature T2 is determined by the system according to the identified material type. The system infers the material surface temperature T1 when the microwave component is involved in the following manner according to the target temperature T2 and the material type: S31. According to Newton's law of cooling, when an object is exposed to hot air, its surface temperature will gradually approach the temperature of the hot air over time. The calculation formula for the change in the surface temperature of the object is as follows: T(t) = T 环境 +(T 初始 -T 环境 )e -kt Equation 1 Where T(t) is the temperature of the material at time t, T 环境 is the temperature of hot air, T 初始 is the initial temperature of the material, k is a positive constant that depends on the properties of the material and the hot air, and t is the drying time; S32. A regression equation is established with drying time as an influencing factor. The optimization equation for drying time and process parameters is: t=116.59-129X1-7.38X2-12.13X3+8X1X3-9.75X2X3+83.83X1 2 +14.58X2 2 Formula 2 In formula 1, t is the drying time for the material to rise from the temperature T1 to the target temperature T2 during microwave heating, min; X1 is the microwave temperature control temperature, °C; X2 is the drying time per cycle, min; X3 is the temperature difference, i.e., T2-T1, °C; S33. Microwave temperature control temperature X1 is selective. For a certain medium or material, the power P absorbed by the medium is proportional to the power frequency f and the square of the electric field strength. The relationship is as follows: P = 2πε0ε'tanδE 2 f Formula 3 In formula 2, ε0 is the dielectric constant of vacuum, and its value is 8.85×10 -12 As / Vm; ε' is the dielectric constant, As / Vm; tanδ is the dielectric tangent loss; E is the electric field strength; f is the microwave power frequency; S34. The system determines the power P absorbed by the medium according to the identified material type, and then can accurately calculate the electric field strength E according to Formula 3, and then calculate the microwave temperature control temperature X1 by the determined electric field strength E and drying time. Then the system reversely calculates the temperature difference X3 according to Formula 2. Since the target temperature T2 is known, the material surface temperature T1 can be accurately calculated. This is the best time to intervene in microwave heating.

5. A microwave hot air oven, characterized in that include: The intelligent control system for a microwave hot air oven as described in any one of claims 1 to 4, further comprising an outer shell, an inner box installed in the outer shell, the microwave component installed on the top of the inner box, the hot air component installed on the back of the inner box, the temperature sensor, the humidity sensor and the material identification sensor are all installed in the inner box, and the intelligent control module is installed in the cavity between the outer shell and the inner box.

6. The microwave hot air oven according to claim 5, characterized in that: The microwave assembly includes a mounting plate arranged on the top of the inner box body, a microwave generating chamber is installed on the mounting plate, a microwave generator is installed in the microwave generating chamber and is connected to the inner box body through a guide cover, a microwave heat dissipation groove is arranged at the rear of the microwave generating chamber, and a power contactor and a frequency converter are respectively installed on the left and right sides of the microwave generator on the mounting plate, and the power contactor and the frequency converter are respectively electrically connected to the microwave generator.

7. The microwave hot air oven according to claim 5, characterized in that: The hot air component includes a rear sealing plate arranged at the rear of the inner box body, the fan is installed on the rear sealing plate, and the fan blades at the front end of the fan are located in a cavity formed by the rear sealing plate, the inner box body, and a partition installed in the inner box body. The electric heating pipe is installed in a ring shape on the outside of the fan blades, and a uniform wind hole plate connected to the inner box body is arranged above the partition.

8. The microwave hot air oven according to claim 5, characterized in that: A door assembly is mounted on the front side of the outer shell, and the door assembly includes a door body and a handle. The door body is mounted on the front side of the outer shell, and the handle is mounted on the door body. In actual use, the door body can be opened and closed by the handle.

9. The microwave hot air oven according to claim 5, characterized in that: A control panel is installed on the front side of the outer shell, and the control panel includes a touch display screen and a power on / off button. The touch display screen is installed on the top of the front side of the outer shell, and the power on / off button is installed on one side of the touch display screen.

10. The microwave hot air oven according to claim 5, characterized in that: A heat dissipation assembly is installed on the bottom plate of the outer shell and is located below the inner box body. The heat dissipation assembly includes a heat dissipation fan mounting bracket and a heat dissipation fan, wherein the heat dissipation fan mounting bracket is fixed on the bottom plate, the heat dissipation fan is installed on the heat dissipation fan mounting bracket and is located below the inner box body, and a heat dissipation hole is arranged on the bottom plate opposite to the heat dissipation fan.

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