An explosion-proof sealed refrigeration and heating circulation device

Abstract

The application relates to the technical field of refrigeration and heating cycle equipment, in particular to an explosion-proof closed refrigeration and heating cycle device, which comprises a heating system, a refrigeration system, a circulation system and a control system; the heating system comprises an explosion-proof electric heater, a temperature sensor and a thermal cut-off protection element; the refrigeration system comprises an explosion-proof compressor, an air-cooled condenser, an evaporator, an explosion-proof fan and a protection element; the circulation system comprises an explosion-proof magnetic force driving circulating pump, a liquid level meter, an outlet temperature sensor and a return temperature sensor; the control system comprises an explosion-proof control box and a controller, which are used for coordinately controlling the systems; the explosion-proof design of the whole machine meets the requirements of explosive gas environment 1 area, IIB level and T4 temperature group, and each electrical component has an explosion-proof mark meeting the corresponding explosion-proof requirements; the application can improve the safety of the closed refrigeration and heating cycle device.

Description

Technical Field

[0001] This application relates to the field of refrigeration and heating circulation equipment technology, and in particular to an explosion-proof closed refrigeration and heating circulation device. Background Technology

[0002] A closed-loop refrigeration and heating circulation device is an integrated device that combines refrigeration, heating, circulation, and closed-loop temperature control. Its core working principle is to achieve energy conversion through compressor refrigeration, electric heater heating, and heat exchanger. The closed-loop control system, which mostly uses PID algorithms, precisely regulates the temperature of the heat transfer fluid within the system. Then, a circulation pump circulates the heat transfer fluid at a stable temperature to the target load. It is widely used in scenarios with high requirements for temperature accuracy and stability, such as pharmaceutical synthesis, biological reactions, environmental simulation testing, automotive parts performance testing, high and low temperature testing of new energy batteries, and semiconductor chip temperature control testing.

[0003] With the rapid development of industries such as chemical, new energy, and pharmaceutical, some application scenarios are located in explosive gas environments, such as Zone 1 explosive gas, mixture class IIB, and temperature group T4, which are high-risk conditions. These scenarios place stringent requirements on the explosion-proof performance of equipment. Existing closed-loop refrigeration and heating circulation devices, in order to adapt to explosion-proof scenarios, only adopt a simplified solution of encapsulating electrical components and selecting explosion-proof types for key components in explosion-proof enclosures. That is, they simply replace core components such as electric heaters, circulating pumps, and compressors with explosion-proof products, and centrally pack ordinary electrical components into explosion-proof enclosures.

[0004] The solution is incomplete, only achieving explosion protection for a single component, without comprehensive explosion-proof design for the entire system. There is a lack of compatibility between the various explosion-proof components, and explosion-proof vulnerabilities exist in electrical connections, signal transmission, and temperature linkage control, failing to meet the overall explosion-proof requirements. The temperature control logic is simple, lacking multi-dimensional temperature monitoring and graded protection mechanisms, making it prone to localized overheating under high-temperature conditions, exceeding the T4 temperature group's maximum surface temperature limit of 135°C, posing a safety hazard of igniting explosive gases. Furthermore, the circulation system lacks a precise liquid level monitoring mechanism, making it prone to dry-burning of the electric heater. Summary of the Invention

[0005] To improve the safety of a closed-loop refrigeration and heating circulation device, this application provides an explosion-proof closed-loop refrigeration and heating circulation device.

[0006] This application provides an explosion-proof, closed-loop refrigeration and heating circulation device, which adopts the following technical solution: including a heating system, a refrigeration system, a circulation system, and a control system; The heating system includes an explosion-proof electric heater, a temperature sensor, and a thermal cutoff protection element. The refrigeration system includes an explosion-proof compressor, an air-cooled condenser, an evaporator, an explosion-proof fan, and protective components; The circulation system includes an explosion-proof magnetically driven circulation pump, a level gauge, an outlet temperature sensor, and an inlet temperature sensor. The control system includes an explosion-proof control box and a controller, which are used to coordinate and control the various systems; The explosion-proof design of the whole machine meets the requirements of Zone 1, IIB, and T4 temperature group for explosive gas environments, and all electrical components have explosion-proof markings that meet the corresponding explosion-proof requirements.

[0007] Optionally, the explosion-proof electric heater has an explosion-proof mark of Ex db IIC T4 Gb and is equipped with a heating tube surface temperature sensor, a heat transfer oil pipe inlet temperature sensor, a heat transfer oil pipe outlet temperature sensor, and a manually reset pressure-type thermal cut-off device; wherein, the heating tube surface temperature is controlled ≤105℃, the heat transfer oil pipe inlet and outlet temperatures are controlled ≤100℃, and the operating temperature of the manually reset pressure-type thermal cut-off device is ≤110℃.

[0008] Optionally, the refrigeration system further includes a first explosion-proof solenoid valve, a second explosion-proof solenoid valve, a capillary tube, a dryer filter, and an automatic reset pressure-type thermal shut-off device; the explosion-proof marking of the explosion-proof compressor is Ex mb sb IIB T4 Gb, and the explosion-proof marking of the explosion-proof fan is Ex db IIB T4 Gb; the operating temperature of the automatic reset pressure-type thermal shut-off device is ≤125℃. The refrigeration system is configured as follows: When the operating temperature is -30℃ to 10℃, the first explosion-proof solenoid valve is open and the second explosion-proof solenoid valve is closed. When the operating temperature is between 10.1℃ and 100℃, the second explosion-proof solenoid valve opens and the first explosion-proof solenoid valve closes.

[0009] Optionally, the circulation system includes an explosion-proof magnetically driven circulation pump, an expansion container, and a float level gauge; the explosion-proof marking of the explosion-proof magnetically driven circulation pump is Ex db IIB T4 Gb, and the explosion-proof marking of the float level gauge is Ex dbIIC T4 Gb; the float level gauge is installed inside the expansion container to monitor the liquid level and prevent the explosion-proof electric heater from dry burning.

[0010] Optionally, the control system has a built-in isolated safety barrier, and the pressure controller, the compressor exhaust temperature automatic reset pressure-type thermal shut-off device, and the heater manual reset pressure-type thermal shut-off device are all powered by the isolated safety barrier; the control system has a material temperature control mode, an outlet temperature control mode, and an inlet temperature control mode, and is configured to execute at least one of the following temperature interlock logic: (a) When the surface temperature of the heating element is >105°C, turn off the heating. (b) When the measured value of the controlled object is greater than the set value of the controlled object + 10°C, the heating shall be turned off; (c) When the measured value of the controlled object is less than the set value of the controlled object + 5°C, turn on the heating; (d) When the measured value of the controlled object is less than the set value of the controlled object -10℃, the refrigeration is turned off; The controlled objects include material temperature, outlet temperature, or return temperature; Furthermore, in the material temperature control mode, the following logic is also executed: (e) When the outlet temperature measurement value is greater than the material temperature measurement value + 30°C, the heating shall be turned off; (f) When the measured outlet temperature exceeds the material temperature setpoint + 30°C, the heating shall be turned off; (g) When the outlet temperature measurement value is less than the material temperature measurement value -30℃, the refrigeration is turned off; (h) When the measured outlet temperature is less than the material temperature setpoint -30℃, the refrigeration is turned off; (i) When the outlet temperature measurement value is greater than the material temperature measurement value + 1°C, the refrigeration is turned on; (j) When the measured outlet temperature is greater than the material temperature setpoint + 1°C, the refrigeration is turned on; In the outlet temperature control mode or the return temperature control mode, the following logic is also executed: (k) When the outlet temperature measurement value is greater than the return temperature measurement value +30°C, the heating is turned off; (l) When the measured outlet temperature is greater than the set outlet or return temperature by 30°C, the heating will be turned off; (m) When the outlet temperature measurement value is less than the return temperature measurement value -30℃, the refrigeration is turned off; (n) When the measured outlet temperature is less than the outlet or return temperature setpoint -30°C, the refrigeration will be turned off; (o) When the outlet temperature measurement value is greater than the return temperature measurement value +1℃, turn on the refrigeration; (p) When the measured outlet temperature is greater than the set outlet or return temperature by 1°C, the cooling system will be activated.

[0011] Optionally, the control system also includes a 7-inch TFT true-color display screen, an explosion-proof mouse, and an RS485 communication interface; the control system is configured to have a scheduled start / stop function, two temperature control modes: setpoint and programmable, an automatic function to plot the temperature characteristic curve of the working process, gradient heating and cooling and linear heating and cooling functions, and follows the MODBUSRTU protocol to realize DCS system online control.

[0012] Optionally, the grounding terminal and markings of the device comply with the requirements of GB / T3836.1; the nameplate markings comply with the requirements of GB / T3836.1; the electrical connections between various explosion-proof electrical products use rubber-sheathed cables and comply with the requirements of GB / T3836.15; the housing, air inlet protective net and air outlet protective net of the device can withstand the impact generated by a 1kg object falling freely from a height of 0.7m.

[0013] In summary, this application includes the following beneficial technical effects: By implementing a comprehensive explosion-proof design for the heating system, refrigeration system, circulation system, and control system, each core electrical component is equipped with a corresponding explosion-proof mark. Electrical connections, signal transmission, and grounding protection all comply with explosion-proof standards. The entire unit meets the requirements of Zone 1, IIB, and T4 temperature groups for explosive gas environments, reducing the problem of existing technologies where only component explosion protection fails and the entire unit fails to be explosion-proof, and significantly improving the safety of operation in high-risk conditions. The heating system is equipped with triple temperature monitoring of the heating tube surface and the inlet and outlet of the heat transfer oil. The refrigeration system has precise control of the solenoid valves in different temperature zones. The control system has three temperature control modes: material, outlet, and return. Combined with graded temperature interlock logic, it can achieve temperature control from -30℃ to 100℃, reducing local overheating. The system features dual thermal cutoff protection with both manual and automatic reset, along with a pressure controller and liquid level monitoring device, forming a multi-layered protection system against overheating, overpressure, and dry burning. The control system incorporates an isolation safety barrier to limit the maximum temperature of critical components, ensuring that the highest surface temperature of the entire unit meets the T4 group standard, i.e., ≤135℃, thereby reducing the risk of igniting explosive gases from the source. The control system integrates a 7-inch TFT true-color display screen and an explosion-proof mouse for easy operation. It features functions such as scheduled start / stop, setpoint and programmable temperature control, curve plotting, gradient temperature rise / fall and linear temperature rise / fall. Through the RS485 interface and in accordance with the MODBUS RTU protocol, it can be seamlessly connected to a DCS system for online control, facilitating processing. Attached Figure Description

[0014] Figure 1 This is a structural diagram of an explosion-proof closed-loop refrigeration and heating circulation device according to this application; Figure 2 This is a block diagram showing the overall connection between the various systems and the control system of the explosion-proof closed refrigeration and heating circulation device of this application; Figure 3 This is a block diagram of the internal composition, power supply and signal transmission architecture of the control system of an explosion-proof closed refrigeration and heating circulation device according to this application; Figure 4 This is a block diagram of the temperature control mode selection of the control system of an explosion-proof closed refrigeration and heating circulation device according to this application; Figure 5This is a block diagram of the temperature interlock and safety control logic of a control system for an explosion-proof, closed-loop refrigeration and heating circulation device according to this application.

[0015] Reference numerals: 1 Explosion-proof compressor, 2 Air-cooled condenser, 3 Dryer filter, 4 Explosion-proof magnetically driven circulating pump, 5 Expansion container, 6 Explosion-proof electric heater, 7 Explosion-proof fan, 9 First explosion-proof solenoid valve, 10 Second explosion-proof solenoid valve, 11 Float level gauge, 12 Pressure controller, 13 Outlet temperature sensor, 14 Heating tube surface temperature sensor, 15 Return temperature sensor, 16 Automatic reset pressure-type thermal shut-off device. Detailed Implementation

[0016] The following is in conjunction with the appendix Figure 1-5 This application will be described in further detail.

[0017] This application discloses an explosion-proof, closed-loop refrigeration and heating circulation device. For example... Figure 1 , 2 As shown in Figures 3, 4, and 5, it includes a heating system, a refrigeration system, a circulation system, and a control system. The control system serves as the core hub, electrically connecting and collecting sensor signals, protection element status, and actuator feedback information from the heating, refrigeration, and circulation systems in real time. Simultaneously, it outputs control signals to drive the various actuators in these systems. The circulation system, acting as the medium carrier, is mechanically connected in series between the heating and refrigeration systems, forming a closed-loop medium circuit consisting of the circulating pump, refrigeration heat exchanger, heating heat exchanger, load, return liquid, and the circulating pump. The heating and refrigeration systems are connected in parallel on the circulation medium circuit, providing heating and cooling sources respectively, which are automatically switched or coordinated by the control system according to temperature ranges and interlocking logic. All explosion-proof electrical components are connected using rubber-sheathed cables conforming to GB / T3836.15, with the lead ends connected to the explosion-proof control box via explosion-proof cable clamp sealing joints and sealed with packing. The grounding terminals and nameplate of the entire unit conform to GB / T3836.1. The casing, air inlet protective mesh, and air outlet protective mesh can withstand an impact of 1 kg from a height of 0.7 m, ensuring the reliability of mechanical protection and explosion-proof sealing.

[0018] The heating system includes an explosion-proof electric heater 6, a heating tube surface temperature sensor 14, a heat transfer oil pipeline inlet temperature sensor, a heat transfer oil pipeline outlet temperature sensor 13, a manually reset pressure-type thermal cut-off device, an expansion container 5, and a float level gauge 11. The heating system is installed inside the heating chamber, and the medium is heat transfer oil, which is used to provide a controllable heat source for the circulating medium.

[0019] The explosion-proof electric heater 6 is the core heating element. The explosion-proof marking of the explosion-proof electric heater 6 is Ex db IIC T4 Gb. The heating element of the explosion-proof electric heater 6 is completely immersed in the heat transfer oil in the heating chamber. The upper part of the heating chamber is connected to the expansion container 5 through a pipeline. The float level gauge 11 is fixedly installed inside the expansion container 5. The explosion-proof marking of the float level gauge 11 is Ex db IIC T4 Gb. The signal line of the float level gauge 11 is connected to the control system to monitor the liquid level in real time. The heating tube surface temperature sensor 14 is directly attached to the outer wall of the heating tube inside the explosion-proof cavity of the explosion-proof electric heater 6. The signal line is connected to the temperature control instrument in the explosion-proof control box. The upper limit is set to ≤105℃. It is used to directly monitor the surface temperature of the heating tube and prevent local overheating. Both the inlet temperature sensor and the outlet temperature sensor of the heat transfer oil pipeline are marked with Ex dbIIB T4 Gb. The inlet temperature sensor and the outlet temperature sensor of the heat transfer oil pipeline are connected in series on the inlet and outlet heating chamber pipelines of the heat transfer oil, respectively. The signal line is connected to the temperature control instrument of the control system. The upper limit is set to ≤100℃. It is used to monitor the overall temperature of the medium, ensure the stability of the outlet temperature of the medium, and avoid over-temperature output. The manual reset pressure-type thermal cut-off device has an operating temperature of ≤110℃. The temperature sensing bulb is tightly attached to the outer surface of the heating chamber. The power supply is provided by the isolation safety barrier in the explosion-proof control box, and the normally closed contact is connected in series in the heating control circuit. When the heating chamber overheats, the heating power supply is forcibly cut off to prevent continuous overheating. After the fault is cleared, it needs to be manually reset to restore the system. It serves as the highest level of hard protection for the heating system.

[0020] The refrigeration system consists of an explosion-proof compressor 1, an air-cooled condenser 2, an explosion-proof fan 7, an evaporator, a first explosion-proof solenoid valve 9, a second explosion-proof solenoid valve 10, a capillary tube, a dryer filter 3, an automatic reset pressure-type thermal shut-off device 16, and a pressure controller 12. It exchanges heat with the circulation system and is electrically linked with the control system. It is used to provide precise cooling capacity in different temperature zones for the circulating medium and to achieve wide-range temperature cooling control.

[0021] The explosion-proof compressor 1 is the core of the refrigeration system, and its explosion-proof marking is Ex mb sb IIB T4 Gb. The exhaust port pipeline is connected in series with the temperature sensor of the automatic reset pressure-type thermal shut-off device 16 and the high-pressure end of the pressure controller 12. The operating temperature of the automatic reset pressure-type thermal shut-off device 16 is ≤125℃. The return gas pipeline is connected in series with the low-pressure end of the pressure controller 12. The compressor power supply and start / stop control signals are output from the control system. An explosion-proof fan 7 is installed on the heat dissipation surface of the air-cooled condenser 2. The explosion-proof fan 7 is marked with Ex db IIB T4 Gb. The explosion-proof fan 7 starts and stops synchronously with the compressor and is electrically linked to it to force heat dissipation and ensure condensation efficiency. Refrigeration circuit flow: compressor, condenser, dryer filter 3, then split into two paths: one path is connected in series with the first explosion-proof solenoid valve 9, capillary tube, and first evaporator; the other path is connected in series with the second explosion-proof solenoid valve 10, capillary tube, and second evaporator; the outlets of the first evaporator and the second evaporator converge back to the compressor; both the first evaporator and the second evaporator exchange heat with the circulating system medium pipeline, forming a cold energy exchange; The automatic reset pressure-type thermal cut-off device 16 and the pressure controller 12 are both powered by the control system's isolated safety barrier and their signals are connected to the control system. They automatically shut down when the compressor discharges overheat, or when the circuit is under high or low pressure, and automatically reset after the fault is cleared, serving as safety protection for the refrigeration system.

[0022] The refrigeration system employs a dual-loop, dual-solenoid valve zoned control system. The first loop is activated in the low-temperature range of -30℃ to 10℃, and the second loop is activated in the medium-temperature range of 10.1℃ to 100℃, achieving precise matching of cooling capacity, high cooling efficiency, and low energy consumption in different temperature zones. The compressor, fan, and solenoid valves are all matched with IIB and T4 explosion-proof ratings and are power-matched to the isolation safety barrier of the control system to avoid electrical sparks generated during the start-up, shutdown, and switching of refrigeration components. The system features dual protection against exhaust temperature and system pressure to prevent compressor overheating and burnout, refrigerant leakage, and overpressure pipe rupture. The explosion-proof fan 7 is synchronized with the compressor to ensure condensation heat dissipation, avoid high-temperature heat accumulation, and meet the T4 surface temperature limit. The refrigeration loop is coupled with the circulation system for heat exchange, achieving stable cooling of the medium, high temperature control accuracy, and minimal temperature fluctuation.

[0023] The circulation system includes an explosion-proof magnetically driven circulation pump 4, an expansion container 5, a float level gauge 11, an outlet temperature sensor 13, an inlet temperature sensor 15, and a medium pipeline. It is connected in series between the heating system and the refrigeration system to form a closed-loop medium circuit and is electrically connected to the control system. It is used to drive the heat transfer fluid to circulate stably, transfer heat, and maintain the system medium balance.

[0024] The explosion-proof magnetic drive circulating pump 4 is the core of the circulating power. The explosion-proof marking of the explosion-proof magnetic drive circulating pump 4 is Ex dbIIB T4 Gb. The pump inlet is connected to the return temperature sensor 15, and the pump outlet is connected to the evaporator inlet of the refrigeration system. The pump power supply and start / stop are controlled by the control system. Medium circuit: circulating pump, refrigeration evaporator, heating chamber, outlet temperature sensor 13, external load, return temperature sensor 15, circulating pump, forming a closed loop circulation; The outlet temperature sensor 13 and the return temperature sensor 15 are connected in series in the medium outlet heating chamber and the return pump pipeline, respectively. The signal line is connected to the control system to monitor the medium output temperature and return temperature in real time. The explosion-proof markings of the outlet temperature sensor 13 and the return temperature sensor 15 are both Ex db IIB T4 Gb. The expansion container 5 is connected to the upper part of the heating chamber, and a float level gauge 11 is installed inside it to absorb the thermal expansion and contraction of the medium, maintain the system pressure balance, and prevent overpressure or cavitation in the pipeline; the level signal is connected to the control system and linked to the start and stop of heating.

[0025] The circulation system adopts an explosion-proof magnetic pump with a shaftless design, eliminating leakage and spark risks, and is suitable for explosion-proof conditions. The closed-loop circulation prevents media leakage and avoids the volatilization of flammable and explosive media. Monitoring by the outlet temperature sensor 13 and return temperature sensor 15 provides real-time feedback on the actual media temperature, offering precise temperature control data for the control system. The expansion container 5 and level gauge automatically compensate for changes in media volume, stabilize system pressure, and prevent dry burning. Stable media flow and uniform heat exchange ensure heating and cooling efficiency, good temperature control stability, and high temperature uniformity. All circulation pipelines, pumps, and sensors are explosion-proof rated, matching the explosion-proof design of the heating, cooling, and control systems, ensuring good overall explosion-proof consistency.

[0026] The control system includes an explosion-proof control box, controller, isolated safety barrier, display screen, explosion-proof mouse, RS485 communication interface, temperature control instrument, relay and protection module. It is the central control unit of the whole machine and electrically connects all sensors and actuators. It integrates temperature control logic and safety interlocks, and is used for coordinated control of the whole machine, precise temperature control, safety protection, human-machine interaction and industrial communication. The display screen is a 7-inch TFT true color display screen.

[0027] The explosion-proof control box is an explosion-proof control box with an explosion-proof marking of Ex db ib IIB T4 Gb. It integrates a controller, isolated safety barrier, temperature controller, relay, and power module. All external electrical leads are connected via explosion-proof cable clamps and sealed with packing. An isolated safety barrier is connected at its input to an automatic reset pressure-type thermal cut-off device for compressor exhaust temperature, a manual reset pressure-type thermal cut-off device for heater, and a pressure controller 12. At its output, it is connected to a controller to provide safe and isolated power supply for the protective components, limit energy, and prevent dangerous sparks. The controller's functions include acquiring all sensor signals; executing temperature control logic; outputting control signals to the heating contactor; and managing the refrigeration compressor, solenoid valve, and circulation pump. The human-computer interaction device includes a 7-inch true-color TFT display screen and an explosion-proof mouse. The 7-inch TFT display screen is installed on the panel of the explosion-proof control box and is electrically connected to the controller to realize parameter setting, status display, curve viewing and operation control. Communication interface: RS485 interface, electrically connected to the controller, conforming to the MODBUSRTU protocol, to realize online communication, remote monitoring and control with the host computer and DCS system.

[0028] Basic temperature interlocking logic The control system has built-in basic temperature interlock logic, which monitors the surface temperature of the heating element and the temperature of the controlled object in real time. The controlled object includes material temperature, outlet temperature, or return temperature. Based on the monitored values, it performs graded start-stop control. a. When the surface temperature of the heating element exceeds 105 degrees Celsius, the control system immediately shuts down the heating system and forcibly cuts off the heating circuit to prevent local overheating caused by excessively high surface temperature of the heating element and to avoid safety risks caused by overheating. b. When the measured value of the controlled object is greater than the set value of the controlled object plus 10 degrees Celsius, the control system automatically shuts down the heating system to prevent the actual temperature from far exceeding the set value and to prevent the system from overheating. c. When the measured value of the controlled object is less than the set value of the controlled object plus 5 degrees Celsius, the control system automatically turns on the heating system to replenish heat in time, so that the temperature gradually approaches the set target and maintains temperature stability. When the measured value of the controlled object is less than the set value of the controlled object minus 10 degrees Celsius, the control system automatically shuts down the refrigeration system to avoid the continuous supply of cooling capacity leading to excessively low temperatures and to prevent the system from operating in an overly cold environment.

[0029] In material temperature control mode, the control system additionally executes dedicated interlocking logic: When the outlet temperature measurement value is greater than the material temperature measurement value plus 30 degrees Celsius, the control system automatically shuts down the heating system to prevent the outlet medium temperature from being much higher than the material temperature and to prevent the material from being overheated. When the measured outlet temperature exceeds the material temperature setpoint plus 30 degrees Celsius, the control system automatically shuts down the heating system to prevent the outlet medium temperature from exceeding the upper limit allowed by the material process. When the outlet temperature measurement is less than the material temperature measurement minus 30 degrees Celsius, the control system automatically shuts down the refrigeration system to prevent the outlet medium temperature from being much lower than the material temperature and to prevent the material from being overcooled. When the measured outlet temperature is less than the material temperature setpoint minus 30 degrees Celsius, the control system automatically shuts down the refrigeration system to prevent the outlet medium temperature from falling below the lower limit allowed by the material process. When the outlet temperature measurement value is greater than the material temperature measurement value plus 1 degree Celsius, the control system automatically turns on the refrigeration system to remove excess heat in time and quickly reduce the temperature deviation between the outlet medium and the material. When the measured outlet temperature exceeds the material temperature setpoint plus 1 degree Celsius, the control system automatically activates the refrigeration system to quickly bring the outlet medium temperature back to the set range, ensuring the accuracy of material temperature control.

[0030] In either the outlet temperature control mode or the return temperature control mode, the control system additionally executes dedicated interlocking logic: When the outlet temperature measurement value is greater than the return temperature measurement value plus 30 degrees Celsius, the control system automatically shuts down the heating system to avoid excessive temperature difference between the inlet and outlet during the medium circulation process and to prevent abnormal heating power. When the measured outlet temperature exceeds the outlet or return temperature setpoint plus 30 degrees Celsius, the control system automatically shuts down the heating system to prevent the medium output temperature from exceeding the process allowable range. When the outlet temperature measurement is less than the return temperature measurement minus 30 degrees Celsius, the control system automatically shuts down the refrigeration system to avoid excessive temperature difference between the inlet and outlet during the medium circulation process and to prevent abnormal refrigeration supply. When the measured outlet temperature is less than the set outlet or return temperature by 30 degrees Celsius, the control system automatically shuts down the refrigeration system to prevent the medium circulation temperature from falling below the allowable range of the process. When the outlet temperature measurement is greater than the return temperature measurement plus 1 degree Celsius, the control system automatically starts the refrigeration system to balance the temperature difference between the inlet and outlet of the medium and maintain a stable circulation temperature. When the measured outlet temperature exceeds the set outlet or return temperature by 1 degree Celsius, the control system automatically activates the refrigeration system to quickly correct the medium temperature deviation and ensure accurate temperature control.

[0031] Under the overall control system, the heating, cooling, and circulation systems work in deep coordination and closed-loop linkage: the circulation pump starts to establish a stable medium circulation; the control system collects all-dimensional parameters in real time, such as the surface of the heating tube, medium inlet and outlet, compressor exhaust, liquid level, and system pressure; according to the set temperature range, the corresponding cooling circuit is automatically activated and the heating is started and stopped as needed; the hierarchical interlocking logic intervenes in real time, and the dangerous circuit is immediately cut off and the alarm is triggered when there is over-temperature, over-pressure, or low liquid level; the whole system is explosion-proof matched, energy isolation, sealing protection, and mechanical protection, and the whole machine meets the requirements of Zone 1, IIB, and T4 explosion-proof; the temperature control range is -30℃ to 100℃, with good stability and strong industrial adaptability.

[0032] The grounding terminal, nameplate, cable connection, protective structure, impact resistance and surface temperature all strictly comply with GB / T3836.1 and GB / T3836.15; the maximum surface temperature is ≤135℃, meeting T4; the explosion-proof electrical components have matching explosion-proof markings, compatible levels and no explosion-proof mismatch; multiple explosion-proof barriers including sealing, isolation, energy limitation and mechanical protection ensure reliable explosion-proof performance of the whole machine and meet regulatory requirements.

[0033] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. An explosion-proof, closed-loop refrigeration and heating circulation device, characterized in that, include: Heating systems, refrigeration systems, circulation systems, and control systems; The heating system includes an explosion-proof electric heater (6), a temperature sensor, and a thermal cutoff protection element; The refrigeration system includes an explosion-proof compressor (1), an air-cooled condenser (2), an evaporator, an explosion-proof fan (7), and protective components; The circulation system includes an explosion-proof magnetically driven circulation pump (4), a level gauge, an outlet temperature sensor (13), and an inlet temperature sensor (15). The control system includes an explosion-proof control box and a controller, which are used to coordinate and control the various systems; The explosion-proof design of the whole machine meets the requirements of Zone 1, IIB, and T4 temperature group for explosive gas environments, and all electrical components have explosion-proof markings that meet the corresponding explosion-proof requirements.

2. The explosion-proof closed-loop refrigeration and heating circulation device according to claim 1, characterized in that: The explosion-proof electric heater (6) is marked with Ex db IIC T4 Gb and is equipped with a heating tube surface temperature sensor (14), a heat transfer oil pipe inlet temperature sensor, a heat transfer oil pipe outlet temperature sensor (13), and a manual reset pressure-type thermal cut-off device; wherein, the heating tube surface temperature is controlled ≤105℃, the heat transfer oil pipe inlet and outlet temperatures are controlled ≤100℃, and the operating temperature of the manual reset pressure-type thermal cut-off device is ≤110℃.

3. The explosion-proof closed-loop refrigeration and heating circulation device according to claim 1, characterized in that: The refrigeration system also includes a first explosion-proof solenoid valve (9), a second explosion-proof solenoid valve (10), a capillary tube, a dryer filter (3), and an automatic reset pressure-type thermal shut-off device (16); the explosion-proof marking of the explosion-proof compressor (1) is Ex mb sb IIB T4 Gb, and the explosion-proof marking of the explosion-proof fan (7) is Ex db IIB T4 Gb; the operating temperature of the automatic reset pressure-type thermal shut-off device (16) is ≤125℃; The refrigeration system is configured as follows: When the operating temperature is -30℃ to 10℃, the first explosion-proof solenoid valve (9) is opened and the second explosion-proof solenoid valve (10) is closed. When the operating temperature is 10.1℃~100℃, the second explosion-proof solenoid valve (10) is opened and the first explosion-proof solenoid valve (9) is closed.

4. The explosion-proof closed-loop refrigeration and heating circulation device according to claim 1, characterized in that: The circulation system includes an explosion-proof magnetically driven circulation pump (4), an expansion container (5), and a float level gauge (11); the explosion-proof marking of the explosion-proof magnetically driven circulation pump (4) is Ex db IIB T4 Gb, and the explosion-proof marking of the float level gauge (11) is Ex db IIC T4Gb; the float level gauge (11) is installed inside the expansion container (5) to monitor the liquid level and prevent the explosion-proof electric heater (6) from burning dry.

5. The explosion-proof closed-loop refrigeration and heating circulation device according to claim 1, characterized in that: The control system has a built-in isolated safety barrier. The pressure controller, the compressor exhaust temperature automatic reset pressure-type thermal shut-off device, and the heater manual reset pressure-type thermal shut-off device are all powered by the isolated safety barrier. The control system has a material temperature control mode, an outlet temperature control mode, and an inlet temperature control mode, and is configured to execute at least one of the following temperature interlock logic: (a) When the surface temperature of the heating element is >105°C, turn off the heating. (b) When the measured value of the controlled object is greater than the set value of the controlled object + 10°C, the heating shall be turned off; (c) When the measured value of the controlled object is less than the set value of the controlled object + 5°C, turn on the heating; (d) When the measured value of the controlled object is less than the set value of the controlled object -10℃, the refrigeration is turned off; The controlled objects include material temperature, outlet temperature, or return temperature; Furthermore, in the material temperature control mode, the following logic is also executed: (e) When the outlet temperature measurement value is greater than the material temperature measurement value + 30°C, the heating shall be turned off; (f) When the measured outlet temperature exceeds the material temperature setpoint + 30°C, the heating shall be turned off; (g) When the outlet temperature measurement value is less than the material temperature measurement value -30℃, the refrigeration is turned off; (h) When the measured outlet temperature is less than the material temperature setpoint -30℃, the refrigeration is turned off; (i) When the outlet temperature measurement value is greater than the material temperature measurement value + 1°C, the refrigeration is turned on; (j) When the measured outlet temperature is greater than the material temperature setpoint + 1°C, the refrigeration is turned on; In the outlet temperature control mode or the return temperature control mode, the following logic is also executed: (k) When the outlet temperature measurement value is greater than the return temperature measurement value +30°C, the heating is turned off; (l) When the measured outlet temperature is greater than the set outlet or return temperature by 30°C, the heating will be turned off; (m) When the outlet temperature measurement value is less than the return temperature measurement value -30℃, the refrigeration is turned off; (n) When the measured outlet temperature is less than the outlet or return temperature setpoint -30°C, the refrigeration will be turned off; (o) When the outlet temperature measurement value is greater than the return temperature measurement value +1℃, turn on the refrigeration; (p) When the measured outlet temperature is greater than the set outlet or return temperature by 1°C, the cooling system will be activated.

6. The explosion-proof closed-loop refrigeration and heating circulation device according to claim 1, characterized in that: The control system also includes a display screen, an explosion-proof mouse, and an RS485 communication interface; the control system is configured to have a scheduled start / stop function, two temperature control modes: setpoint and programmable, an automatic function to plot the temperature characteristic curve of the working process, gradient heating and cooling and linear heating and cooling functions, and follows the MODBUS RTU protocol to realize online control of the DCS system.

7. The explosion-proof closed-loop refrigeration and heating circulation device according to claim 1, characterized in that: The device's casing, air inlet protective net, and air outlet protective net can withstand the impact of a 1kg object falling freely from a height of 0.7m.

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