Food cold and hot tunnel intelligent temperature control system

Abstract

The invention discloses a food cold and hot tunnel intelligent temperature control system, which comprises a central control module, a multi-temperature-zone temperature control module, a layer vehicle positioning and state sensing module, an energy switching module, a data storage and tracing module and an alarm module, and real-time two-way communication among the modules is realized through an industrial Ethernet. The central control module is an embedded industrial controller integrated with an ARM architecture processor and an FPGA chip, through the design of multi-temperature-zone independent regulation and linkage pre-regulation, a plurality of independent temperature zones are effectively separated by silica gel sealing heat insulation layers, and in combination with parameter pre-regulation before temperature zone switching, a reasonable temperature gradient is formed by adjacent temperature zones, so that the temperature gradient of the temperature zones is improved. The quality problems of skin cracking, collapse and the like caused by temperature mutation of the food are avoided; high-precision sensing and closed-loop control are adopted, a high-precision temperature sensor and a high-frequency data acquisition device are adopted to feed back temperature zone data in real time, a high-speed data processing unit is matched to achieve rapid instruction issuing, and a stable temperature control closed loop is formed.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of food processing equipment, and particularly relates to an intelligent temperature control system for a food cold-hot tunnel. BACKGROUND

[0002] In the food processing industry, a cold-hot tunnel processing device is a core device for processes such as baking, quick freezing, and fresh food preservation, and the temperature control precision and operation efficiency of the device directly determine the food quality stability, processing period, and energy consumption. With the development of the food industry towards scale and refinement, the market has higher requirements for the intelligentization, multi-scene adaptability, and energy saving of the temperature control system of the device.

[0003] The existing cold-hot tunnel temperature control system mostly adopts a single temperature zone or a simple partition control mode, and adjacent temperature zones lack effective heat insulation and linkage adjustment mechanisms, which are prone to temperature crosstalk, resulting in quality fluctuations of food when the temperature zones are switched due to temperature mutation, such as waves in baked food due to uneven baking, uneven surface, and other problems such as skin cracking, excessive surface pores, formation of hard layers, and inconsistent internal and external textures. At the same time, the temperature control execution unit mostly adopts a single energy heating and single air path cooling structure, and the heating rate and cooling rate adjustment range is narrow, which cannot adapt to the differentiated temperature control needs of different types of food (such as heat-sensitive cakes and high-moisture cooked food), and the energy switching relies on manual operation, which is difficult to achieve optimal energy consumption control according to the energy supply state of the power grid, steam, and other energy sources. SUMMARY

[0004] The purpose of the present application is to provide an intelligent temperature control system for a food cold-hot tunnel to solve the problems raised in the background.

[0005] To achieve the above purpose, the present application provides the following technical solution: an intelligent temperature control system for a food cold-hot tunnel, comprising a central control module, a multi-temperature zone temperature control module, a layer car positioning and state sensing module, an energy switching module, a data storage and traceability module, and an alarm module, and the modules are in real-time bidirectional communication through an industrial Ethernet; The central control module is the core of the system and is installed in the equipment control cabinet. The central control module is an embedded industrial controller using an integrated ARM architecture processor and an FPGA chip. The ARM architecture processor runs a Linux operating system and a temperature control algorithm program. The FPGA chip realizes at least 8 channels of synchronous data acquisition and control signal output. At least 5 standard temperature control process libraries of food are pre-stored and custom process curve editing is supported; The multi-temperature zone temperature control module is integrated in the cold-hot tunnel body, which is used to divide the cold-hot tunnel body into several independent temperature zones (N≥3) along the layer car conveying direction, and each independent temperature zone is equipped with an independent heating unit, a cooling unit, a temperature and humidity acquisition unit, and an air circulation unit; The layer car positioning and state sensing module is integrated on the layer car and is composed of a laser position sensor, a weight sensor and a photoelectric encoder, realizing sensing of the layer car position, load and conveying speed; the energy switching module includes an energy detection unit and a switching execution unit, used for realizing intelligent switching of the electric-steam dual energy heating mode in the cold-hot tunnel body; The data storage and tracing module is integrated in the central control module, adopting a dual storage architecture of an industrial-grade SD card and a cloud server; The alarm module is installed on the top of the equipment control cabinet and has dual alarm functions of audible and visual alarm and SMS alarm.

[0006] Preferably, in the multi-temperature zone temperature control module, the heating unit is a double-path parallel heating structure of an electric heating pipe and a steam coil pipe, the electric heating pipe realizes stepless adjustment of 0-100% power through a solid-state relay, the steam coil pipe is connected in series with an electric regulating valve and the regulating accuracy reaches 0.1% opening, and the two can be independently started or cooperatively operated; the cooling unit includes a medium cold air path and a high cold air path, the medium cold air path is configured with a variable frequency fan with a power of 5.5kW, the high cold air path is configured with a variable frequency fan with a power of 11kW, and both air paths are connected in series with electric regulating dampers, and the cooling rate control of 0.5℃ / min-5℃ / min is realized through the cooperative adjustment of the fan rotating speed and the damper opening, the heating and cooling unit structure and the regulating mode of the multi-temperature zone temperature control module are refined, the stepless accurate regulation of heating power and the wide range cooling rate control are realized, and the temperature control accuracy and adaptability are improved.

[0007] Preferably, the temperature and humidity collection unit is internally provided with 3-5 PT1000 temperature sensors and one temperature and humidity transmitter, and the air flow circulation unit is two groups of variable frequency circulating fans, and the two groups of variable frequency circulating fans are respectively symmetrically arranged at the top and the bottom of each independent temperature zone, and the fan rotating speed regulating range is 500r / min-2000r / min.

[0008] Preferably, the temperature sensor is packaged with polytetrafluoroethylene to prevent dewing and corrosion, the measurement range is-20℃~150℃, the accuracy is ±0.1℃, and is respectively arranged at the inlet side, the center area, the outlet side of the layer car and the four corners of the inner wall of the cold-hot tunnel body, and the sampling frequency of the temperature and humidity transmitter is 10Hz.

[0009] Preferably, hydraulic elevators are arranged on both sides of the cold-hot tunnel body, a conveying track is arranged in the cold-hot tunnel body, and a tray car for conveying the layer car into the cold-hot tunnel body is slidably connected in the conveying track, so that the layer car can be conveniently and stably conveyed in and out of the tunnel, and the continuous performance of the temperature control process is ensured.

[0010] A temperature control method of a food cold-hot tunnel intelligent temperature control system specifically includes the following steps: S1, process initialization: the user selects a preset process curve or edits a custom process curve through the human-machine interface of the central control module, inputs the food type, weight, target temperature and holding time parameters, and the system automatically matches the initial temperature control parameters of each temperature zone; S2, layer car conveying and positioning: place the layer car loaded with food on the tray car, start the hydraulic elevator to convey the layer car to the entrance of the cold-hot tunnel body, and the laser position sensor, weight sensor and photoelectric encoder of the layer car positioning and state sensing module respectively collect the initial position, load weight and conveying speed data of the layer car, and transmit them to the central control module; S3, multi-temperature zone dynamic temperature control: the central control module sends control instructions to the heating unit and cooling unit of each temperature zone according to the process parameters and sensing data; the heating unit realizes rapid heating through electric-steam dual energy collaborative regulation, the cooling unit realizes accurate cooling through double air path collaborative regulation, and the temperature and humidity acquisition unit collects real-time parameters of each temperature zone and feeds back to the central control module, forming a closed loop control; S4, intelligent energy switching: the energy switching module detects the power grid voltage, steam pressure and energy consumption data in real time, and when the steam pressure is ≥0.3MPa and the energy consumption is more than 10% lower than the electric heating mode, it automatically switches to the steam heating mode; when the steam pressure is <0.1MPa or the power grid voltage is stable at 380V±5%, it automatically switches to the electric heating mode, and the temperature fluctuation of the temperature zone during the switching process is ≤±0.3℃; S5, data storage and traceability: the data storage and traceability module stores the temperature and humidity, equipment running state, energy consumption and process parameter data of each temperature zone in real time, and synchronously updates the local SD card and cloud server, supports data query and report export; S6, abnormal alarm and processing: when the central control module detects that the parameter deviation exceeds the standard, the equipment fails or the energy is abnormal, it immediately triggers the audible and visual alarm and SMS alarm of the alarm module, displays the fault code and processing suggestion; if the fault lasts for more than 10s, the system automatically executes emergency stop protection and cuts off the power supply of the heating / cooling unit; S7, process end: when the food reaches the target holding time, the central control module issues a process end instruction, the tray car conveys the layer car to the outlet of the cold-hot tunnel body, the hydraulic elevator removes the layer car, and the system generates a process completion report and saves it.

[0011] Preferably, in the step S3, the multi-temperature zone dynamic temperature control adopts a temperature zone linkage adjustment method, when the layer vehicle enters the i+1 temperature zone from the i temperature zone (i

[0012] Preferably, in the step S3, the multi-temperature zone dynamic temperature control further includes layer vehicle load distribution compensation control, the weight sensor collects load weight distribution data (partition accuracy ≤0.1 kg) of different regions of the layer vehicle, when the load of other regions of the layer vehicle is higher than the average load by ≥15%, the central control module controls the rotation speed of the air circulation fan corresponding to the region to increase by 10%-20%, and simultaneously adjusts the output power of the heating unit / cooling unit of the region by ±8%, so as to ensure that the temperature deviation of food in different regions of the layer vehicle is ≤±0.4℃; in the step S3, the multi-temperature zone dynamic temperature control further includes layer vehicle load distribution compensation control, the weight sensor collects load weight distribution data of different regions of the layer vehicle, when the load of a certain region reaches a set threshold value, the central control module controls the rotation speed of the air circulation fan corresponding to the region to increase, and simultaneously adjusts the output power of the heating unit and the cooling unit of the region, so as to ensure that the temperature of food in different regions of the layer vehicle is uniform, and through collecting load distribution data and adjusting the rotation speed of the fan and the heating / cooling power, the temperature of food in different regions of the layer vehicle is ensured to be uniform.

[0013] Preferably, in the step S7, when the equipment is in a standby state, the central control module controls each temperature zone to maintain a standby temperature of 50℃±5℃, and the energy switching module preferentially selects a steam heating mode (if the steam pressure is ≥0.2MPa); when it is detected that the layer vehicle enters the entrance of the cold-hot tunnel body, the central control module switches to a process initialization state within 3s, and each temperature zone starts adjustment according to the initial parameters of the step S1, which saves preheating time by more than 40% compared with normal temperature start, optimizes the standby and start modes of the equipment, and realizes rapid start and saves preheating time by maintaining a specific standby temperature and preferentially selecting an energy-saving energy source, thereby improving efficiency and energy saving.

[0014] Compared with the prior art, the application has the following beneficial effects: (1) Through the multi-temperature zone independent control and linkage pre-conditioning design, multiple independent temperature zones are effectively separated by a silica gel sealing and heat insulation layer, which greatly reduces the temperature cross talk between temperature zones. In combination with the parameter pre-conditioning before the temperature zone switching, a reasonable temperature gradient is formed between adjacent temperature zones, so that the skin cracking and collapse of food caused by temperature mutation are avoided. Through the load distribution compensation mechanism, the load difference of different regions is accurately detected by the partition weight sensor, the air circulation intensity and heat exchange power of the corresponding region are adjusted, the food temperature in different regions of the layer vehicle is ensured to be uniform, and high-precision sensing and closed-loop control are adopted. High-precision temperature sensors and high-frequency data acquisition equipment are used to feedback temperature zone data in real time, and a stable temperature control closed loop is formed by cooperating with a high-speed data processing unit to realize rapid issuance of instructions and ensure the overall temperature control precision.

[0015] (2) An electric-steam dual-energy collaborative mode is adopted: the supply state and use cost of the two kinds of energy are monitored in real time by an energy detection unit, the optimal heating mode is automatically selected based on a preset algorithm, steam heating is preferentially adopted when steam supply is sufficient and economic efficiency is better, and the mode is seamlessly switched to electric heating mode when steam supply is insufficient. The temperature of the temperature zone is ensured to be stable through parameter pre-conditioning during the switching process, and there is no obvious fluctuation. Meanwhile, the system is designed to have a low-energy standby mode. When the equipment is in standby, a relatively low holding temperature is maintained, and the energy consumption is greatly reduced compared with normal temperature standby. When starting, the system can be quickly switched to the process running state, significantly shortening the preheating time and reducing the energy waste in the starting stage.

[0016] (3) The central control module pre-stores a standard process library of a plurality of common foods, and supports user editing of a custom process curve according to actual needs, so that the system can be flexibly adapted to a plurality of food processing scenes such as baking, quick freezing and fresh food preservation. The cooling unit realizes wide-range cooling rate control through a double-air-path collaborative adjustment design, and the heating unit supports stepless power adjustment, so that the differentiated temperature control requirements of different characteristic foods such as heat-sensitive cakes and high-moisture cooked foods can be met. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is a module block diagram of the system of the application; Figure 2 It is a flow block diagram of the system of the application; Figure 3 It is a structural schematic view of the layer vehicle of the application; Figure 4 It is a process layout view of the layer vehicle and the cold-hot tunnel of the application; Figure 5 It is a process flow view of the millet cake online baking and steaming and quick cooling line of the application; Figure 6 It is a process flow view of the steamed bun anti-adhesion quick cooling line of the application.

[0018] In the figure: 1, cold and hot tunnel body; 2, layer car; 3, hydraulic elevator; 4, conveying track; 5, tray car; 6, layer plate. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0020] In the description of the present application, it should be noted that, unless otherwise explicitly specified and limited, the terms "mounting", "provided with", "sleeved", "sleeved", "connected" and the like should be understood broadly, for example, "connected" can be fixedly connected, or can be detachably connected, or integrally connected; can be mechanically connected, or can be electrically connected; can be directly connected, or can be indirectly connected through an intermediate medium; can be the communication inside two elements, and those skilled in the art can understand the specific meaning of the above terms in the present application according to the specific circumstances.

[0021] The present application provides a kind of intelligent temperature control system of food cold and hot tunnel as shown in Figures 1-6 It includes central control module that bears overall planning and coordination and core operation function, multi-temperature zone temperature control module that realizes multi-region accurate temperature control, layer car positioning and state sensing module that realizes real-time sensing of the state of carrying carrier, energy switching module that realizes energy efficient adaptation, data storage and traceability module that guarantees data traceability and alarm module that guarantees operation safety, each module builds real-time two-way communication network through industrial Ethernet, forms the temperature control system of collaborative linkage; The central control module is integrated in the equipment control cabinet as the system core, uses the embedded industrial controller of the fusion of ARM architecture processor and FPGA chip, wherein the ARM architecture processor carries Linux operating system, runs temperature control core algorithm program and provides man-machine interaction support, the FPGA chip has at least 8 channels of synchronous data acquisition and control signal output capability, realizes high-speed data processing and instruction issuing;Central control module is built-in at least 5 kinds of standard temperature control process library of typical food, supports user to edit custom process curve through interactive interface, can automatically match and generate each module operating parameter according to input parameter; The multi-temperature zone temperature control module is integrated in the cold and hot tunnel body, divides the tunnel into not less than 3 independent temperature zones along the conveying direction of layer car, each temperature zone forms a closed temperature control space and is provided with independent heating unit, cooling unit, temperature and humidity acquisition unit and air circulation unit, realizes independent regulation and control of temperature, humidity and air flow state of each temperature zone, meets the differentiated temperature control needs of different process stages; The layer car positioning and state sensing module is integrated in the layer car body and is composed of a laser position sensor, a weight sensor and a photoelectric encoder. The laser position sensor collects real-time spatial position information of the layer car in the tunnel. The weight sensor detects the load weight and distribution state of the layer car. The photoelectric encoder collects the conveying speed data of the layer car. The data of the three are coordinated to provide the basis for the state of the carrying carrier for precise temperature control. The energy switching module includes an energy detection unit for energy state monitoring and a switching execution unit for executing switching actions. It has intelligent identification and switching capability of dual energy modes of electric heating and steam heating. It can automatically select the optimal heating mode according to the energy supply state, ensure the stability of temperature control, and reduce energy consumption. The data storage and traceability module is integrated in the central control module and adopts a dual backup architecture of local storage with an industrial-grade SD card and remote storage with a cloud server. It records all data of the temperature control process in real time and supports data query, statistical analysis and report export. The alarm module is installed on the top of the equipment control cabinet and has dual warning functions of audible and visual alarm and SMS alarm. It can output corresponding warning signals and fault information according to the fault type to ensure timely response to abnormal conditions.

[0022] In the multi-temperature zone temperature control module, the heating unit adopts a composite heating structure of dual parallel electric heating pipes and steam coils. The electric heating pipe realizes stepless adjustment of 0-100% power through a solid-state relay to meet the demand for rapid heating. The steam coil is connected in series with an electric regulating valve with an adjustment accuracy of 0.1% opening to realize precise temperature control. The two can be independently started or cooperatively operated to adapt to different heating rate requirements. The cooling unit adopts a dual-path design of medium and high cooling air paths. The medium cooling air path is configured with a 5.5kW frequency conversion fan, and the high cooling air path is configured with an 11kW frequency conversion fan. Both paths are connected in series with electric regulating dampers. Through the cooperative adjustment of fan speed and damper opening, a wide range of cooling rate control of 0.5℃ / min-5℃ / min is realized to meet different food cooling process requirements.

[0023] The temperature and humidity acquisition unit is built-in with 3-5 PT1000 temperature sensors and a temperature and humidity transmitter. The PT1000 temperature sensor realizes multi-point temperature acquisition, and the temperature and humidity transmitter synchronously acquires humidity data in the temperature zone. The air circulation unit is composed of two groups of frequency conversion circulating fans. The two groups of fans are symmetrically arranged at the top and bottom of each independent temperature zone to form an up-down convection air circulation mode. The fan speed adjustment range is 500r / min-2000r / min, which can adjust the air circulation intensity according to the temperature control requirements of the temperature zone to ensure the temperature uniformity in the temperature zone.

[0024] The temperature sensor adopts a polytetrafluoroethylene anti-dew and corrosion-resistant package, is suitable for a high-humidity and corrosive environment of food processing, has a measurement range of -20°C to 150°C, and an accuracy of ±0.1°C; the sensor is arranged at four corners of the inner wall of the cold and hot tunnel body 1 at the inlet side, the central area, the outlet side and the layer car 2, to realize omnibearing temperature collection of the load area of the layer car 2 and the tunnel environment; the temperature and humidity transmitter has a sampling frequency of 10 Hz, to ensure real-time feedback of temperature and humidity data.

[0025] The cold and hot tunnel body 1 is provided with hydraulic elevators 3 on both sides, to realize lifting and conveying of the layer car 2, and to adapt to the feeding and discharging requirements of different heights; the cold and hot tunnel body 1 is provided with a conveying track 4, and the conveying track 4 is slidably connected with a tray car 5, the tray car 5 serving as a carrier of the layer car 2, to realize stable conveying of the layer car 2 in the cold and hot tunnel body 1, and to ensure that the layer car 2 accurately passes through each temperature zone according to the process rhythm.

[0026] A temperature control method of a food cold and hot tunnel intelligent temperature control system comprises the following steps: S1, process initialization: a user completes process parameter configuration through a man-machine interface of a central control module, can select a preset process curve or edit a custom process curve, inputs core parameters such as a food type, a weight, a target temperature and a holding time, and the system generates initial temperature control parameters of each temperature zone based on process library matching or algorithm operation, to complete process start preparation; S2, layer car conveying and positioning: the layer car 2 loaded with food is placed on the tray car 5, the hydraulic elevators 3 are started to convey the layer car 2 to the inlet of the cold and hot tunnel body 1, a layer car positioning and state sensing module is started synchronously, a laser position sensor, a weight sensor and a photoelectric encoder respectively collect initial position, load weight and conveying speed data of the layer car 2, and transmit the data to the central control module to establish an initial state file; S3, multi-temperature zone dynamic temperature control: the central control module issues accurate control instructions to each temperature zone heating unit and cooling unit based on process parameters and sensing data; the heating unit realizes a target temperature rising rate through electric-steam dual energy collaborative regulation, and the cooling unit realizes a target cooling rate through double air path collaborative regulation; a temperature and humidity collection unit collects parameters of each temperature zone in real time and feeds back to the central control module, to form a closed-loop temperature control mechanism of “instruction-execution-feedback-adjustment”; S4, energy intelligent switching: an energy switching module monitors power grid voltage, steam pressure and energy consumption data in real time, establishes an energy cost performance evaluation model, automatically switches to a steam heating mode when the steam pressure is greater than or equal to 0.3 MPa and the energy consumption is lower than 10% of the electric heating mode, and automatically switches to the electric heating mode when the steam pressure is less than 0.1 MPa or the power grid voltage is stable at 380V±5%; parameter pre-adjustment is performed during the switching process to ensure that the temperature fluctuation of the temperature zone is less than or equal to ±0.3°C, and to ensure process continuity; S5, data storage and traceability: the data storage and traceability module collects and stores the whole process data such as temperature and humidity of each temperature zone, equipment running state, energy consumption and process parameters in real time, and the local SD card and the cloud server are synchronized in real time, supporting data query and report export according to time, food type and other dimensions, realizing production process traceability; S6, abnormal alarm and processing: the central control module compares the monitoring data with the process threshold in real time, and when it detects that the parameter deviation exceeds the standard, the equipment fails or the energy is abnormal, it immediately triggers the alarm module, synchronously starts the sound and light alarm and the short message alarm, displays the fault code and processing suggestion; if the fault lasts for more than 10s and is not removed, the system automatically executes emergency stop protection, cuts off the power supply of the heating / cooling unit, and prevents the fault from expanding; S7, process end: when the food reaches the target holding time, the central control module issues a process end instruction, the tray car transports the layer car to the tunnel outlet, the hydraulic elevator moves the layer car out, and the system automatically generates a process completion report and stores it, completing a single process cycle.

[0027] In the step S3, the multi-temperature zone dynamic temperature control adopts a temperature zone linkage adjustment strategy, the central control module predicts the temperature zone switching time based on the layer car position data, and adjusts the temperature control parameters of the i+1 temperature zone 5s before the layer car enters the i+1 temperature zone from the ith temperature zone (i

[0028] In the step S3, the multi-temperature zone dynamic temperature control includes a layer car load distribution compensation control mechanism, the weight sensor collects load weight distribution data of different regions of the layer car 2 by partition, and the partition accuracy is ≤0.1kg; when the load of a certain region is higher than the average load by ≥15%, the central control module automatically adjusts the speed of the air circulation fan corresponding to the region by 10%-20% to enhance the heat exchange effect, and adjusts the output power of the heating unit / cooling unit of the region by ±8% to ensure that the temperature deviation of the food in different regions of the layer car 2 is ≤±0.4℃, and to ensure the uniformity of heating / cooling.

[0029] In the step S7, the device has an energy-saving standby mode, when the device is in standby state, the central control module controls each temperature zone to maintain at a standby temperature of 50℃±5℃, reducing standby energy consumption; the energy switching module preferentially selects the steam heating mode (when the steam pressure is ≥0.2MPa); when it is detected that the layer car 2 enters the entrance of the cold-hot tunnel body 1, the central control module quickly switches to the process initialization state within 3s, and each temperature zone starts adjusting according to the initial parameters of step S1, which saves more than 40% of the preheating time compared with normal temperature start, and improves the start efficiency of the device.

[0030] Embodiment 1.1 Cold-hot tunnel body and carrying mechanism parameters The cold-hot tunnel body 1 is made of 304 stainless steel material, and the overall size is 4500mm x 1200mm x 1800mm (length x width x height). It is divided into two or more independent temperature zones (temperature zone 1, temperature zone 2) along the conveying direction of the layer car. The adjacent temperature zones are separated by a silica gel sealing and heat insulation layer to effectively avoid temperature cross talk (cross talk amount ≤0.5℃ / h). Two parallel conveying tracks 4 are laid in the tunnel, with a track spacing of 800mm, suitable for the operation of the tray car 5. The tray car is driven by a servo motor, and the conveying speed adjustment range is 0.1-0.5m / min, with a positioning accuracy of ±2mm; The layer car 2 uses the existing production mode size, with a size of 1000mm x 800mm x 1500mm. It is equipped with 10 detachable stainless steel layer plates 6, with a layer spacing of 120mm. The independent moving base is installed at the bottom of the layer car, and the polyurethane silent wheel is used to realize stable operation (operation shaking degree ≤1mm) with the cooperation of the laser position sensor. Two hydraulic lifts 3 are symmetrically installed on both sides of the tunnel, with a lifting stroke of 0-1800mm, a lifting speed of 50mm / s, a load capacity of 500kg, and the realization of automatic feeding and discharging of the layer car; 1.2 Core module specific configuration Central control module: ARMCortex-A9 architecture processor (1.2GHz) + Xilinx Spartan-6 FPGA chip; Linux 4.14 operating system; 8 food process libraries such as rice cakes and steamed buns are pre-stored; the human-machine interface is a 10-inch touch screen, which supports process curve visual editing; Multi-temperature zone temperature control module: temperature zone 1: electric heating pipe (2kW x 2) + steam coil (Φ50mm); medium cold air path (5.5kW variable frequency fan) + high cold air path (11kW variable frequency fan); temperature zone 2: electric heating pipe (3kW x 2) + steam coil (Φ50mm) + steam injection device; Each temperature zone is equipped with 5 PT1000 sensors + 1 temperature and humidity transmitter; 1 variable frequency circulating fan (speed 500-2000r / min) at the top / bottom; Layer car positioning and state sensing module: laser position sensor (model Keyence LR-ZB250CP, accuracy ±0.1mm); 8 partitioned weight sensors (accuracy 0.1kg, distributed at the corners and center of the layer car); photoelectric encoder (resolution 1000 lines); Energy detection unit of energy switching module: power grid voltage detector (range 300-450V), steam pressure sensor (0-1MPa), electric energy meter (accuracy 0.5 level); switching execution unit: electric three-way valve (response time ≤1s), solid-state relay; Data storage and alarm module: industrial-grade 32GB SD card + Aliyun IoT platform; Alarm module: 110 dB sound and light alarm + SMS cat (support 5 receiving numbers); fault code library contains 20 common faults.

[0031] Two, millet cake processing technology implementation (to solve the problem of uneven baking, collapse) Using 75℃ high temperature baking (millet from the original 20℃ slowly heated to 60℃, baking and fermentation), 10 minutes after taking out and then 100℃ steaming process, through the temperature control system to achieve precise temperature control and load compensation.

[0032] 1. Process initialization The operator selects "millet cake standard process" through the touch screen, and the system automatically loads the parameters: food type is millet cake (moisture content 45%), single tray weight 5kg, temperature zone 1 target temperature 75℃ (10min, core process requirement: millet slowly heated from 20℃ to 60℃, baking and fermentation), while configuring the subsequent steaming stage associated parameters: temperature zone 2 steaming temperature 100℃, steaming time is set according to actual production needs, the system reserves steaming process parameter editing interface.

[0033] 2. Layer car conveying and positioning Put the layer car 2 loaded with 10 layers of millet cake raw dough (millet initial temperature 20℃, 500g per layer, evenly laid on non-stick layer plate 6) into tray car 5, start hydraulic elevator 3 to transport layer car 2 to the entrance of cold and hot tunnel body 1, at this time: laser position sensor detects that the initial position deviation of layer car is ≤0.5mm; 8 weight sensors collect load distribution data, display 4th partition (lower right corner) load 5.8kg, which is 16% higher than average load (5kg); photoelectric encoder detects the initial conveying speed of tray car 0.2m / min, all data are transmitted to the central control module.

[0034] 3. Multi-temperature zone dynamic temperature control 3.1. Temperature zone linkage adjustment: when layer car 2 enters temperature zone 1 at a speed of 0.2m / min, central control module outputs control signals synchronously through FPGA chip, starts electric heating pipe and steam coil to cooperate heating (steam pressure 0.4MPa), ensures that millet slowly heats from initial 20℃ to 60℃, maintains temperature zone 1 overall environment temperature 75℃ during heating process, realizes baking and fermentation at the same time; when baking to 10min, the system issues a taking-out instruction, central control module controls tray car 5 to transport layer car 2 to the exit of cold and hot tunnel body 1, and hydraulic elevator 3 removes layer car 2 from the tunnel.

[0035] 3.2. Load distribution compensation: After analyzing the load data, the central control module sends instructions to the circulating fan corresponding to zone 4 in zone 1, increasing the speed from 1500 r / min to 1700 r / min (increased by 13.3%); at the same time, the power of the electric heating pipe in this area is increased by 8%, and the opening of the steam coil is increased by 0.08%. Through real-time feedback of PT1000 sensor, the temperature difference between the millet paste temperature in zone 4 and the center zone is stable at ±0.3℃, ensuring uniformity of baking and fermentation.

[0036] 3.3. Steaming stage control: The millet cake layer vehicle removed from the cold and hot tunnel body 1 is transported to the steaming zone 2. The operator can start the preset steaming process through the human-machine interface of the central control module. The system controls the steaming equipment in zone 2 to heat up to 100℃ and maintain stable, completing the subsequent steaming process of millet cake. The steaming process data is uploaded to the data storage and traceability module simultaneously.

[0037] 4. Energy intelligent switching During the process, the energy switching module detects in real time: when the steam pressure is stable at 0.4MPa, the steam heating energy consumption is 1.2kWh / 10min, which is 20% lower than the electric heating mode (1.5kWh / 10min). The system automatically switches to steam heating mode. The steam pressure temporarily dropped to 0.09MPa (lasting 3s) during the process. The system immediately switches to electric heating mode. The temperature fluctuation in zone 1 during the switching process is only 0.2℃, which does not affect the process stability.

[0038] 5. Data storage, alarm and process end The data storage module records the temperature curve of each zone (sampling interval 1s), steam pressure change and load compensation parameters in real time, and updates the local SD card and cloud simultaneously. When the process is executed to 10min, the system sends a baking completion prompt, and records the baking stage data at the same time. The system triggers an audible and visual alarm and sends a message to the device administrator (content: "Zone 1 temperature rise rate is abnormal, deviating from the preset curve, please check the heating unit"). Adjust the opening of the steam regulating valve within 1s, and the temperature returns to normal. After the process is completed, the tray car transports the layer car to the outlet, and the hydraulic elevator removes the layer car. The system generates a "millet cake process report" containing temperature data and energy consumption statistics in each stage (steam heating accounts for 75%, single batch energy consumption is reduced by 30%).

[0039] III. Baozi processing technology implementation (solve the problem of sticking) Adopt "high temperature out of the furnace-quick cooling" process, realize gradient cooling through temperature control system, control the skin dehydration rate.

[0040] Core process parameters: temperature zone 1 (just out of the furnace, normal temperature ventilation cooling) 95℃ (2min), temperature zone 2 (medium cooling wind cooling) 50℃ (3min), temperature zone 3 (high cooling wind cooling, skin dehydration) 10℃ (5min); cooling rate 3℃ / min, outlet temperature ≤15℃. Key control: when the layer car enters the temperature zone 3, the high cooling wind path and the medium cooling wind path are started cooperatively, the center and the edge of the bun are made to have a temperature difference ≤0.5℃ through load compensation, the skin dehydration is uniform, and sticking is avoided; after the process is finished, it is detected that the skin moisture content of the bun is reduced to 18%, and the sticking rate is reduced from 15% to 0% compared with the traditional cooling mode.

[0041] 1. Product quality: the surface of the millet cake is flat after baking, there is no collapse in the middle, the temperature difference between the center and the corner is ≤0.4℃; the buns are not stuck, and the skin feels uniform.

[0042] 2. Energy consumption performance: the steam heating mode reduces energy consumption by 20%-30% compared with the pure electric heating mode.

[0043] 3. System stability: continuous operation for 8 hours, normal communication of each module, alarm response time ≤1s, temperature control accuracy ±0.3℃.

[0044] Finally, it should be pointed out that: the above only describes the preferred embodiments of the present application and is not intended to limit the present application, although the present application has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features, any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A smart temperature control system for hot and cold tunnels in food processing, characterized in that, It includes a central control module, a multi-temperature zone temperature control module, a floor vehicle positioning and status sensing module, an energy switching module, a data storage and traceability module, and an alarm module, and the modules communicate with each other in real time via industrial Ethernet. The central control module is the core of the system and is installed in the equipment control cabinet. The central control module is an embedded industrial controller that integrates an ARM architecture processor and an FPGA chip. The multi-temperature zone temperature control module is integrated into the hot and cold tunnel body (1) and is used to divide the hot and cold tunnel body (1) into several independent temperature zones along the conveying direction of the deck car. Each independent temperature zone is equipped with an independent heating unit, cooling unit, temperature and humidity acquisition unit and airflow circulation unit. The platform car positioning and status sensing module is integrated and installed on the platform car (2). The platform car positioning and status sensing module consists of a laser position sensor, a weight sensor and a photoelectric encoder to realize the sensing of the position, load and conveying speed of the platform car (2). The energy switching module includes an energy detection unit and a switching execution unit, which are used to realize the intelligent switching of electric-steam dual energy heating mode in the cold and hot tunnel body (1); The data storage and traceability module is integrated into the central control module and adopts a dual storage architecture of industrial-grade SD card and cloud server; The alarm module is installed on the top of the equipment control cabinet and has dual alarm functions: audible and visual alarm and SMS alarm.

2. The intelligent temperature control system for a food hot and cold tunnel according to claim 1, characterized in that: In the multi-temperature zone temperature control module, the heating unit is a dual-path parallel heating structure of electric heating tube and steam coil, and the cooling unit includes a medium-cooling air path and a high-cooling air path, and both the medium-cooling air path and the high-cooling air path are connected in series with an electric regulating damper.

3. The intelligent temperature control system for a food hot and cold tunnel according to claim 1, characterized in that: The temperature and humidity acquisition unit consists of a temperature sensor and a temperature and humidity transmitter, and the airflow circulation unit consists of two sets of variable frequency circulating fans, which are symmetrically arranged at the top and bottom of each independent temperature zone.

4. The intelligent temperature control system for a food hot and cold tunnel according to claim 3, characterized in that: The temperature sensors are encapsulated with polytetrafluoroethylene to prevent condensation and corrosion, and are respectively arranged on the entrance side, central area, exit side of the deck car (2) and the four corners of the inner wall of the hot and cold tunnel body (1).

5. The intelligent temperature control system for a food hot and cold tunnel according to claim 1, characterized in that: Hydraulic lifts (3) are provided on both sides of the hot and cold tunnel body (1). A conveying rail (4) is provided inside the hot and cold tunnel body (1), and a pallet truck (5) for conveying the floor car (2) into the hot and cold tunnel body (1) is slidably connected inside the conveying rail (4).

6. A smart temperature control system for a food hot and cold tunnel according to any one of claims 1-5, characterized in that, The temperature control method of this intelligent temperature control system for hot and cold food tunnels specifically includes the following steps: S1. Process initialization: Users select a preset process curve or edit a custom process curve through the human-machine interface of the central control module, and input the food type, weight, target temperature and heat preservation time parameters. The system automatically matches the initial temperature control parameters of each temperature zone. S2, Layer Cart Conveying and Positioning: Place the layer cart loaded with food on the pallet cart (5), start the hydraulic lift (3) to transport the layer cart (2) to the entrance of the cold and hot tunnel body (1). The laser position sensor, weight sensor and photoelectric encoder of the layer cart positioning and status sensing module collect the initial position, load weight and conveying speed data of the layer cart (2) respectively, and transmit them to the central control module. S3, Multi-zone dynamic temperature control: The central control module sends control commands to the heating and cooling units of each temperature zone based on process parameters and sensing data; the heating unit achieves rapid heating through the coordinated regulation of electric and steam dual energy sources, and the cooling unit achieves precise cooling through the coordinated regulation of dual air paths; the temperature and humidity acquisition unit collects parameters of each temperature zone in real time and feeds them back to the central control module to form a closed-loop control. S4. Intelligent Energy Switching: The energy switching module monitors the grid voltage, steam pressure, and energy consumption data in real time. When the steam pressure is ≥0.3MPa and the energy consumption is more than 10% lower than that of the electric heating mode, it automatically switches to the steam heating mode. When the steam pressure is <0.1MPa or the grid voltage is stable at 380V±5%, it automatically switches to the electric heating mode. During the switching process, the temperature fluctuation of the temperature zone is kept ≤±0.3℃. S5. Data storage and traceability: The data storage and traceability module stores temperature and humidity, equipment operating status, energy consumption and process parameters of each temperature zone in real time. The local SD card is updated synchronously with the cloud server, and data query and report export are supported. S6. Abnormal Alarm and Handling: When the central control module detects excessive parameter deviation, equipment failure, or energy abnormality, it immediately triggers the audible and visual alarm and SMS alarm of the alarm module, displays the fault code and handling suggestions; if the fault lasts for more than 10 seconds, the system automatically performs emergency stop protection and cuts off the power supply to the heating / cooling unit. S7. Process End: When the food reaches the target heat preservation time, the central control module issues a process end command. The pallet truck (5) transports the layer truck (2) to the exit of the hot and cold tunnel body (1). The hydraulic lift (3) moves the layer truck (2) out. The system generates a process completion report and saves it.

7. The intelligent temperature control system for a food hot and cold tunnel according to claim 6, characterized in that: In step S3, the multi-temperature zone dynamic temperature control adopts the temperature zone linkage adjustment method. When the stack cart (2) enters the i+1 temperature zone from the i-th temperature zone, the central control module adjusts the temperature control parameters of the i+1 temperature zone 5 seconds in advance according to the position data of the stack cart (2) so that the temperature gradient of the adjacent temperature zones is controlled at 5-10℃, and the food quality is prevented from declining due to sudden temperature changes.

8. The intelligent temperature control system for a food hot and cold tunnel according to claim 6, characterized in that: In step S3, the multi-temperature zone dynamic temperature control also includes load distribution compensation control of the stack cart. The weight sensor collects the load weight distribution data of different areas of the stack cart (2). When the load of a certain area reaches the set threshold compared with the average load, the central control module controls the speed of the airflow circulation fan corresponding to that area to increase, and at the same time adjusts the output power of the heating unit and cooling unit in that area to ensure that the temperature of the food in different areas of the stack cart (2) is uniform.

9. The intelligent temperature control system for a food hot and cold tunnel according to claim 6, characterized in that: In step S7, when the equipment is in standby mode, the central control module controls each temperature zone to maintain a standby temperature of 50℃±5℃, and the energy switching module prioritizes steam heating mode.

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