Self-expansion cascade ultralow-temperature refrigeration house for biological collection insect killing
By combining the R404A/R23 cascade refrigeration system with a self-expanding pressure-reducing expansion tank, the problem of temperature fluctuations caused by the start-up, shutdown, and mode switching of the refrigeration system was solved, achieving precise temperature and humidity control of the preservation environment for biological artifacts and ensuring the integrity of the artifacts.
Patent Information
- Application Number
- CN202511290949.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-10
- Publication Date
- 2026-01-16
AI Technical Summary
Existing ultra-low temperature cold storage facilities are prone to temperature fluctuations when the refrigeration system is started, stopped, or when the mode is switched, which affects the insecticidal effect and neglects humidity control, resulting in damage to the collection.
It adopts an R404A/R23 cascade refrigeration system, combined with a self-expanding and depressurizing expansion tank and a PID controller, along with a PLC controller and temperature and humidity sensors, to achieve precise control of temperature accuracy ±2℃ and humidity accuracy ±5%RH. It also features a hot gas bypass and compressor liquid injection pipeline stabilization system, and a heating device to prevent frost formation.
It achieves precise control of temperature and humidity in cold storage, ensures stability during the constant temperature phase, avoids damage to the collections, and improves the operational reliability of the system.
Smart Images
Figure CN121346436A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of biological artifact preservation equipment, and in particular to a self-expanding cascade ultra-low temperature cold storage for insecticidal purposes of biological artifacts. Background Technology
[0002] Biological artifacts (such as plant and animal specimens, archival documents, etc.) require regular pest control and sterilization for long-term preservation. Traditional methods are divided into chemical pest control (such as fumigation) and physical pest control (primarily cryogenic freezing). Chemical methods pose problems of pesticide residue and environmental pollution. Currently, the most commonly used physical pest control method is cryogenic freezing. Cryogenic freezing kills pests by lowering the temperature to their lethal range (below -10°C). The most widely used refrigeration systems in cryogenic freezing are two-stage compression refrigeration systems and cascade refrigeration systems, with the R404A / R23 cascade refrigeration system being the most common. While cascade refrigeration systems in physical methods can achieve ultra-low temperatures of -40°C, the switching and starting / stopping of the system's operating modes significantly affect the temperature of the cold storage. In related technologies, switchable cascade ultra-low temperature biological artifact pest control cold storage only controls the temperature of the cold storage, neglecting humidity control.
[0003] Biological artifacts (such as plant and animal specimens, archival documents, etc.) are susceptible to insect infestation during long-term preservation and require regular pest control treatment. Traditional pest control methods mainly include chemical and physical methods. Chemical methods use fumigants and other agents, which are highly effective at killing insects, but pose risks such as pesticide residues, environmental pollution, and potential health hazards to operators, and are gradually being phased out. Among physical methods, low-temperature freezing has become the mainstream approach due to its pollution-free nature and relatively safe operation.
[0004] Currently, low-temperature freezing methods often employ cascade refrigeration systems (such as R404A / R23 systems) to achieve ultra-low temperature environments below -40°C, thus killing pests and their eggs. However, existing cold storage refrigeration systems are prone to temperature fluctuations during start-up, shutdown, or mode switching, affecting the insecticidal effect and even damaging the artifacts. Furthermore, most cold storage refrigeration systems focus only on temperature control, neglecting humidity regulation, leading to dehydration and embrittlement of artifacts in low-temperature environments. Their structural designs also often lack anti-frost and anti-clogging functions, causing observation windows to frost and obstruct vision, humidification system drip trays to frost and clog below zero degrees Celsius, and defrosting water during rewarming causing a sudden increase in humidity, damaging the preservation environment of the artifacts.
[0005] Therefore, it is necessary to set up an ultra-low temperature insecticidal cold storage that can achieve precise temperature and humidity control, ensure stable system operation, and not damage the collection. Summary of the Invention
[0006] This application provides a self-expanding cascade ultra-low temperature cold storage for insect control of biological artifacts, which overcomes the problem of the impact of system mode switching and start-up / shutdown on the cold storage temperature, and increases the control of humidity, thereby ensuring the integrity of biological artifacts.
[0007] This application provides a self-expanding cascade ultra-low temperature cold storage for insecticidal purposes of biological artifacts, comprising:
[0008] The cold storage room is constructed of polyurethane insulation panels, with stainless steel panels on the inner wall and color steel panels on the outer wall. It is also equipped with observation windows and fresh air doors.
[0009] The refrigeration system is located inside the cold storage room and adopts an R404A / R23 cascade refrigeration unit, which includes an R404A high-temperature refrigeration system, an R23 low-temperature refrigeration system and an air handling unit. The R23 low-temperature refrigeration system is also equipped with an expansion tank that can perform self-expansion and pressure reduction.
[0010] The control system, connected to the refrigeration system, integrates a PID controller, a PLC controller, and a temperature and humidity sensor to control the parameters of the refrigeration system during the refrigeration process.
[0011] It also includes an insecticidal program, which is loaded into the control system and can control the refrigeration system to perform three stages: cooling, constant temperature, and reheating.
[0012] Preferably, the observation window is a multi-layered vacuum glass covered with an electrically heated film.
[0013] Preferably, the fresh air door is an automatically adjustable ventilation door, located at the top and bottom of the cold storage room, which can introduce fresh air for ventilation after the pest control is completed.
[0014] Preferably, the air handling unit includes an evaporator, a fan, a preheater, a main heater, and a humidifier, wherein the preheater, the main heater, and the humidifier are respectively connected to the PID controller.
[0015] Preferably, both the R404A high-temperature refrigeration system and the R23 low-temperature refrigeration system are equipped with a hot gas bypass pipeline and a compressor liquid injection pipeline to regulate the refrigerant flow and pressure in the refrigeration system, wherein:
[0016] The hot gas bypass pipeline is used to control the refrigerant bypass backflow through a solenoid valve when the cooling capacity is too large, so as to reduce the system cooling capacity and stabilize the temperature.
[0017] The compressor injection line is used to inject liquid refrigerant via a solenoid valve when the compressor discharge temperature is too high, in order to reduce the suction temperature and prevent the compressor from overheating and being damaged.
[0018] Preferably, the R23 cryogenic refrigeration system further includes an expansion pipeline, which includes multiple expansion tanks, a dryer filter, a capillary tube, and multiple solenoid valves.
[0019] Preferably, a crankcase pressure regulating valve for controlling the evaporation pressure of the R23 low-temperature refrigeration system is further provided between the R23 low-temperature refrigeration system and the air handling unit.
[0020] Preferably, the humidifier nozzle is equipped with an electric heating device, which can be automatically turned on when the temperature is below zero degrees Celsius.
[0021] Preferably, the control system further includes a computer, measurement and control software, and a data acquisition device, capable of loading and executing the insecticidal program.
[0022] Preferably, the three stages controlled by the insecticidal program are as follows:
[0023] During the cooling phase, the R404A high-temperature refrigeration system and the R23 low-temperature refrigeration system are activated to reduce the internal temperature of the cold storage room from the ambient temperature to -40±2℃.
[0024] During the constant temperature stage, the temperature and humidity inside the cold storage room are controlled by the PID controller to be maintained at -40℃±2℃ and 57±5%RH for at least 72 hours;
[0025] During the rewarming phase, the temperature inside the cold storage room is gradually raised back to normal temperature, and the fresh air door is opened to introduce fresh air.
[0026] The beneficial effects of this application are as follows:
[0027] This application discloses a self-expanding cascade ultra-low temperature cold storage for insecticidal purposes. Through the coordinated operation of an R404A high-temperature refrigeration system and an R23 low-temperature refrigeration system, it achieves rapid cooling of the cold storage room's temperature, meeting the requirements for insecticidal effects against low-temperature shocks. The expansion tank within the cascade refrigeration unit provides self-expansion and pressure reduction, ensuring stable control during start-up, shutdown, or mode switching. The control system utilizes a PID controller, PLC controller, and temperature and humidity sensors to dynamically adjust refrigeration parameters, achieving a temperature accuracy of ±2℃ and a humidity accuracy of ±5%RH. This ensures stability during the constant temperature phase, preventing temperature and humidity fluctuations from affecting the insecticidal effect and avoiding damage to the collection due to improper temperature control. Furthermore, the inclusion of heating devices at the observation window and humidifier enhances the overall operational reliability of the cold storage. Attached Figure Description
[0028] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0029] Figure 1 A schematic diagram of the overall structure of the self-expanding cascade ultra-low temperature cold storage for insect control of biological collections provided in this application embodiment;
[0030] Figure 2 This is a schematic diagram of the overall structure of the refrigeration system provided in the embodiments of this application;
[0031] Figure 3 This is a schematic diagram illustrating the operating principle of the refrigeration system provided in the embodiments of this application;
[0032] Figure 4 This is a schematic diagram of the temperature and humidity change curves during the insecticidal process provided in the embodiments of this application. Detailed Implementation
[0033] The technical solutions of this application will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0034] The following is combined with Figures 1-4 This application describes a self-expanding cascade ultra-low temperature cold storage for insecticidal purposes used on biological collections, as provided in the embodiments of this application.
[0035] Reference Figure 1 and Figure 2 As shown, 100 is an R404A high-temperature refrigeration system, 200 is an R23 low-temperature refrigeration system, and 300 is an air handling unit. The self-expanding cascade ultra-low temperature cold storage for insecticidal purposes of biological collections provided in this application includes a cold storage room body, which is made of polyurethane insulation board, with stainless steel plate as the inner wall and color steel plate as the outer wall. It is also equipped with an observation window and a fresh air door.
[0036] The refrigeration system is located inside the cold storage room and adopts an R404A / R23 cascade refrigeration unit, which includes an R404A high-temperature refrigeration system 100, an R23 low-temperature refrigeration system 200 and an air handling unit 300. The R23 low-temperature refrigeration system 200 is also equipped with an expansion tank 218 that can perform self-expansion and pressure reduction.
[0037] The control system, connected to the refrigeration system, integrates a PID controller, a PLC controller, and temperature and humidity sensors to control parameters during the refrigeration process, achieving a temperature accuracy of ±2℃ and a humidity accuracy of ±5%RH.
[0038] It also includes an insecticidal program, which is loaded into the control system and consists of three stages: cooling, constant temperature, and reheating.
[0039] The synergistic operation of the R404A high-temperature refrigeration system 100 and the R23 low-temperature refrigeration system 200 in the refrigeration system achieves rapid cooling of the room temperature, meeting the needs of pest control under low-temperature shocks. The expansion tank in the cascade refrigeration unit provides self-expansion and pressure reduction to ensure stable control during start-up, shutdown, or mode switching. The PID controller, PLC controller, and temperature and humidity sensors in the control system work together to dynamically adjust refrigeration parameters, achieving a temperature accuracy of ±2℃ and a humidity accuracy of ±5%RH. This ensures stability during the constant temperature phase, avoids temperature and humidity fluctuations affecting the pest control effect, and prevents damage to the stored items due to improper temperature control. Furthermore, the installation of appropriate heating devices at the observation window and humidifier enhances the overall operational reliability of the cold storage.
[0040] In some specific embodiments, the observation window is a multi-layered vacuum glass covered with an electrically heated film to prevent frost and condensation from forming on the observation window in low-temperature environments.
[0041] In some specific embodiments, the fresh air door is an automatically adjustable ventilation door, located at the top and bottom of the cold storage room, which can introduce fresh air for ventilation after the pest control is completed.
[0042] Specifically, regarding the structure of the cold storage unit in this application, the internal dimensions are 3.7m × 3.3m × 2.4m, with a volume of approximately 29.3m³. The cold storage unit is constructed of 150mm thick polyurethane insulation panels, with 2mm thick color steel plates on the outer walls and 2mm thick stainless steel plates on the inner walls. The storage door is an insulated convex door, measuring 1.2m × 2m. Observation windows are provided on the doors to allow for observation of the interior. These windows utilize multi-layered vacuum glass and are equipped with an electric heating film to prevent frost and condensation. Automatically adjustable fresh air vents are located at the top and bottom of the walls, allowing for ventilation of the storage unit after pest control of the biological artifacts.
[0043] Please continue reading. Figure 3 and Figure 4 ,in, Figure 3 This is a schematic diagram illustrating the operating principle of the refrigeration system provided in the embodiments of this application. Figure 4 This is a schematic diagram of the temperature and humidity change curves during the insecticidal process provided in an embodiment of this application;
[0044] In some specific embodiments, the air handling unit 300 includes an evaporator, a fan, a preheater, a main heater, and a humidifier. The preheater, main heater, and humidifier are each connected to a PID controller. The PID controller controls the temperature and humidity of the cold storage by controlling the preheater, main heater, and humidifier, achieving precise control of the temperature at -40±2℃ and the humidity at 57±5%RH during the constant temperature stage.
[0045] Regarding the composition of the refrigeration system of this application, the refrigeration system of the cold storage uses an R404A / R23 cascade refrigeration system, wherein the air handling unit 300 is installed inside the side wall of the cold storage, the air inside the storage enters from the bottom and exits from the top, and the air handling unit 300 includes an evaporator, a fan, a preheater, a main heater and a humidifier.
[0046] In some specific embodiments, both the R404A high-temperature refrigeration system 100 and the R23 low-temperature refrigeration system 200 are provided with hot gas bypass lines and compressor liquid injection lines to regulate the refrigerant flow and pressure in the refrigeration system.
[0047] By setting up hot gas bypass pipelines and compressor liquid injection pipelines, the refrigerant flow and pressure can be automatically adjusted according to the cooling load and compressor status to avoid the system being too cold or too hot, and to ensure stable operation of the system during rapid cooling, long-term constant temperature and reheating, thereby improving the accuracy of temperature and humidity control and the reliability of equipment.
[0048] Among them, the hot gas bypass pipeline is used to control the bypass flow of some refrigerant through a solenoid valve when the cooling capacity is too large, so as to reduce the cooling capacity of the system and stabilize the temperature.
[0049] The compressor liquid injection line is used to inject liquid refrigerant through a solenoid valve when the compressor discharge temperature is too high, so as to reduce the suction temperature and prevent the compressor from overheating and being damaged.
[0050] The hot gas bypass line and compressor liquid injection line of the R404A high-temperature refrigeration system 100 can be controlled by solenoid valve 114b and electronic hot gas bypass valve 216, while the hot gas bypass line and compressor liquid injection line of the R23 low-temperature refrigeration system 200 can be controlled by solenoid valve 114e and solenoid valve 214e.
[0051] In some specific embodiments, the R23 cryogenic refrigeration system 200 is further provided with an expansion line, which includes a solenoid valve 214c, a solenoid valve 214d, an expansion tank 218, a dryer filter 205b, and a capillary tube 219.
[0052] In some specific embodiments, a crankcase pressure regulating valve 221 is also provided between the R23 cryogenic refrigeration system 200 and the air handling unit 300 to control the evaporation pressure of the R23 cryogenic refrigeration system 200, so as to ensure stable operation of the system at a higher evaporation temperature.
[0053] Specifically, the cascade refrigeration system includes an R404A high-temperature stage refrigeration system 100 and an R23 low-temperature stage refrigeration system 200, as shown in the system schematic diagram. Figure 1 As shown.
[0054] Among them, 101 is an R404A high-temperature compressor, and 201 is an R23 low-temperature compressor; 117 is an evaporator-condenser using a plate heat exchanger; 217 is a finned evaporator; 102 and 202 are both air-cooled condensers; 103 and 203 are both oil separators; 104 and 204 are both liquid receivers; 105, 205a, and 205b are dryer filters; 106 and 206 are gas-liquid separators; 218 is an expansion tank; 219 is a capillary tube; 107 and 207 are high and low pressure relays; 220 is a single high pressure relay; 108 and 208 are high pressure gauges; 10 9 and 209 are low-pressure gauges; 110 and 210 are temperature protectors; 111 and 211 are temperature switches; 112 and 212 are sight glasses; 221 is a crankcase pressure regulating valve; 113, 213a, and 213b are thermostatic expansion valves; 114a, 114b, 114e, 214a, 214b, 214c, 214d, and 214e are solenoid valves; 115 and 215 are injection valves; 116 and 216 are a mechanical hot gas bypass valve and an electronic hot gas bypass valve, respectively; 222a, 222b, 222c, and 222d are ball valves; 223 is a safety valve.
[0055] The R404A / R23 cascade refrigeration system is equipped with a hot gas bypass line and a compressor liquid injection line. The hot gas bypass line of the R404A high-temperature refrigeration system 100 is the line containing the solenoid valve 114b and the mechanical hot gas bypass valve 116. The line containing the electronic hot gas bypass valve 216 is the hot gas bypass line of the R23 low-temperature refrigeration system 200. When the system cooling capacity is too large, the PLC controller will control the solenoid valve 114b and the electronic hot gas bypass valve 216 to make a part of the refrigerant return directly from the oil separator to the gas-liquid separator inlet to reduce the system cooling capacity.
[0056] The compressor injection lines of the R404A high-temperature refrigeration system 100 and the R23 low-temperature refrigeration system 200 are respectively the lines containing solenoid valve 114e and injection valve 115 and the lines containing solenoid valve 214e and injection valve 215. When the compressor discharge temperature is too high, the PLC controller will control solenoid valve 114e and solenoid valve 214e to open, and a portion of the condensed refrigerant will return to the compressor inlet through the injection line to reduce the compressor suction temperature, thereby reducing the compressor discharge temperature.
[0057] The R23 low-temperature refrigeration system 200 is also equipped with an expansion pipeline, which includes solenoid valves 214c and 214d, an expansion tank 218, a dryer filter 205b, and a capillary tube 219. Solenoid valve 214c is a normally open solenoid valve, and solenoid valve 214d is a normally closed solenoid valve.
[0058] When the discharge pressure of compressor 201 is too high, the PLC controller will control the solenoid valve 214d to open, and the refrigerant will be depressurized through the expansion pipe to the compressor pressure range. Then the solenoid valve 214d will be closed. When the refrigeration unit stops, the pressure of the refrigerant in the R23 low temperature refrigeration system 200 will become very high. In order to ensure the safety and normal operation of the system, the PLC controller will control the solenoid valve 214c to open, so that the refrigerant becomes gaseous after passing through the expansion pipe, and most of the refrigerant is stored in the expansion tank 218.
[0059] The R23 low-temperature refrigeration system 200 has a crankcase pressure regulating valve 221 at the inlet of the gas-liquid separator 206. The evaporation pressure of the R23 low-temperature refrigeration system 200 increases with the increase of the evaporation temperature. The crankcase pressure regulating valve can reduce the pressure of the refrigerant at the inlet of the compressor 201 to the allowable range of the compressor, preventing the compressor from being damaged due to excessive suction pressure. This allows the R23 low-temperature refrigeration system 200 to operate and circulate at a higher evaporation temperature.
[0060] In some specific embodiments, the water receiving tray and drain pipe at the humidifier nozzle are equipped with an electric heating device, which can be automatically turned on when the temperature is below zero degrees to prevent frost and blockage and avoid humidity fluctuations during the warming process.
[0061] In some specific embodiments, the control system also includes a computer, measurement and control software, and a data acquisition unit, capable of loading and executing insecticidal programs.
[0062] In some specific embodiments, the three stages of the insecticidal process are as follows:
[0063] During the cooling phase, the R404A high-temperature refrigeration system 100 and the R23 low-temperature refrigeration system 200 are activated to lower the internal temperature of the cold storage room from the ambient temperature to -40±2℃.
[0064] During the constant temperature phase, the temperature and humidity inside the cold storage room are maintained at -40℃±2℃ and 57±5%RH for at least 72 hours by a PID controller.
[0065] During the rewarming phase, the internal temperature of the cold storage room is gradually raised to room temperature, and fresh air is introduced by opening the fresh air door.
[0066] Specifically, regarding the composition and function of the control system of this application, the control system consists of a computer, measurement and control software, high-precision temperature and humidity sensors, control cabinet, etc. The control cabinet includes: a data acquisition unit, a PLC controller, a PID controller, a touch screen, relays, etc. The PLC controller can control all the switching quantities of the cold storage refrigeration system, and can also control the output of the heater and humidifier through the power regulator. The PID controller controls the temperature and humidity of the cold storage by controlling the preheater, main heater and humidifier. The alarm information of the cold storage system can be dynamically displayed and has audible and visual alarm functions. The setting of all parameters, the recording and saving of data can be completed through the corresponding measurement and control software, which is existing technology that can be easily known to those skilled in the art, and will not be described in detail here. In addition, the pest control of biological collections can be completed automatically by loading the pest control program with one click and starting the program with one click in the corresponding measurement and control software in the control system. Furthermore, the start and stop of the equipment can be controlled through the touch screen, making the operation of the entire control system more convenient.
[0067] The process of using an insecticide program to kill insects in biological collections in this application is as follows:
[0068] (1) Rapid cooling process in 1 hour: turn on the cascade refrigeration system, preheater, door and window heating and humidifier to rapidly reduce the temperature in the cold storage from room temperature to -40±2℃.
[0069] (2) 72h constant temperature process: When the temperature drops to -40℃, the constant temperature and humidity control begins. The temperature and humidity of the cold storage need to be stabilized at -40±2℃ and 57±5%RH, respectively. The PID controller controls the temperature and humidity of the cold storage by controlling the preheater and humidifier.
[0070] (3) 12-hour rewarming process: The main heater is turned on to slowly raise the temperature inside the cold storage to room temperature. A PID controller is used to regulate the temperature and humidity of the cold storage, controlling the preheater, main heater, and humidifier to maintain a stable humidity of 57±5%RH. After the insecticide treatment of the biological collection is completed, the fresh air door is automatically opened to introduce fresh air for ventilation. The actual insecticide treatment process shows the temperature and humidity changes over time in the cold storage as follows: Figure 4 As shown.
[0071] On the other hand, this application addresses the problem that the melting of frost in the water tray at the humidifier nozzle greatly affects the humidity during the rewarming process by using electric heating for the water tray and drain pipe. When the temperature inside the cold storage is below zero degrees Celsius, the electric heating is turned on to prevent frost from forming on the water tray or ice from condensing and clogging the drain pipe.
[0072] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.
[0073] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.
[0074] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between components; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.
[0075] In this application, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.
[0076] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.
Claims
1. A self-inflating cascade ultra-low temperature freezer for biological collections for insect control, characterized in that, The application relates to a cold storage room body composed of polyurethane insulation boards, wherein the inner wall is made of stainless steel plates, the outer wall is made of color steel plates, and observation windows and fresh air doors are further arranged on the color steel plates. The refrigeration system is arranged in the cold storage room body and adopts an R404A / R23 cascade refrigerating unit, which comprises an R404A high-temperature refrigeration system, an R23 low-temperature refrigeration system and an air handling unit, wherein the R23 low-temperature refrigeration system is further provided with an expansion tank capable of self-expanding and reducing pressure. The control system is connected with the refrigeration system and is integrated with a PID regulator, a PLC controller and a temperature and humidity sensor, and is used for controlling the parameters in the refrigeration process of the refrigeration system. The control system is further provided with a pest control program capable of controlling the refrigeration system to perform three-stage processes of cooling, constant temperature and rewarming. The observation windows are multilayer vacuum glass, and the outer surfaces of the multilayer vacuum glass are covered with electric heating films.
2. The self-inflating multi-stage ultra-low temperature freezer for biological collections according to claim 1, characterized in that, The fresh air doors are automatic adjustment type ventilation doors and are respectively arranged at the top and bottom of the cold storage room body, and can introduce fresh air for ventilation after the pest control is completed.
3. The self-inflating multi-stage UTL freezer for biological collections according to claim 2, characterized in that, The air handling unit comprises an evaporator, a fan, a pre-heater, a main heater and a humidifier, wherein the pre-heater, the main heater and the humidifier are respectively connected with the PID regulator.
4. The self-inflating multi-stage UTL freezer for biological collections according to claim 3, characterized in that, The R404A high-temperature refrigeration system and the R23 low-temperature refrigeration system are respectively provided with a hot gas bypass pipeline and a compressor liquid injection pipeline, so as to adjust the refrigerant flow and pressure in the refrigeration system.
5. The self-inflating multi-stage UTL freezer for biological collections according to claim 4, characterized in that, The hot gas bypass pipeline is used for controlling part of refrigerant to bypass and return flow through an electromagnetic valve when the refrigeration capacity is too large, so as to reduce the system refrigeration capacity and stabilize the temperature. The compressor liquid injection pipeline is used for controlling liquid refrigerant to be injected through an electromagnetic valve when the compressor exhaust temperature is too high, so as to reduce the suction temperature and prevent the compressor from being damaged due to overheating. The R23 low-temperature refrigeration system is further provided with an expansion pipeline, and the expansion pipeline comprises a plurality of expansion tanks, a drying filter, a capillary tube and a plurality of electromagnetic valves.
6. The self-inflating multi-stage ultra-low temperature freezer for biological collections according to claim 5, characterized in that, The R23 low-temperature refrigeration system and the air handling unit are further provided with a crankcase pressure regulating valve used for controlling the evaporation pressure of the R23 low-temperature refrigeration system.
7. The self-inflating multi-stage UTL freezer for biological collections according to claim 6, characterized in that, An electric heating device is arranged at the humidifier nozzle, and the electric heating device can be automatically started when the temperature is below zero.
8. The self-inflating multi-stage UTL freezer for biological collections according to claim 7, characterized in that, The control system further comprises a computer, measurement and control software and a data collector, and can load and execute the pest control program.
9. The self-inflating multi-stage UTL freezer for biological collections according to claim 8, characterized in that, The three stages controlled by the pest control program are as follows:
10. The self-inflating multi-stage ultra-low temperature freezer for biological collections according to claim 1, characterized in that, In the cooling stage, the R404A high-temperature refrigeration system and the R23 low-temperature refrigeration system are started, and the temperature in the cold storage room body is reduced from the ambient temperature to -40+ / -2 DEG C; In the constant temperature stage, the PID regulator is used to control the temperature and humidity in the cold storage room body to be maintained at -40 DEG C + / -2 DEG C and 57+ / -5% RH respectively for at least 72 hours; In the rewarming stage, the temperature in the cold storage room body is gradually increased to normal temperature, and the fresh air door is opened to introduce fresh air.