A fresh-keeping cold storage

Abstract

A fresh-keeping cold storage belongs to the field of cold storage design. The fresh-keeping cold storage includes a cold storage body, a plasma sterilization system, an ozone chilling system, a temperature control system, an air circulation system, and a central control system. By combining plasma sterilization technology and ozone chilling technology, the preservation effect of vegetables and fruits is significantly improved. The cold storage's multi-layer insulation design and precise temperature control system ensure the stability and uniformity of the storage environment. The air circulation system is optimized to ensure efficient and uniform air circulation and avoid temperature and humidity blind spots. The entire system uses intelligent control to achieve fully automated operation, improve work efficiency, and reduce manual intervention. The use of environmentally friendly materials and energy-saving design reduces the impact on the environment and achieves the goal of energy conservation and environmental protection.

Description

Technical Field

[0001] The present invention belongs to the field of cold storage design and relates to a new type of cold storage, specifically to the design and construction of a cold storage using plasma sterilization technology and ozone refrigeration technology to ensure that vegetables and fruits remain fresh during transportation and storage. Background Art

[0002] Cold chain logistics systems are an integral part of modern agriculture and the food industry, and one of their core facilities is cold storage. The development of cold storage technology has played a key role in the preservation and transportation of agricultural products. However, traditional cold storage technology, which primarily relies on low temperatures to extend the shelf life of vegetables and fruits, has numerous limitations and shortcomings.

[0003] Traditional cold storage technology inhibits the growth and metabolism of microorganisms by lowering the ambient temperature, thereby extending the shelf life of food. However, this method has several significant limitations:

[0004] Limited microbial inhibition: Traditional cold storage primarily inhibits microbial growth and reproduction by lowering the temperature. However, while low temperatures can slow microbial metabolism, they cannot completely kill them. This means that while microbial growth rates are significantly reduced in low-temperature environments, they remain viable and can slowly reproduce. Food stored for long periods of time can gradually become susceptible to microbial contamination, ultimately leading to spoilage and deterioration. Therefore, relying solely on low temperatures cannot fully guarantee the long-term safety and quality of food.

[0005] Difficulty in temperature control: Maintaining a uniform low-temperature environment in large-scale cold storage is an extremely challenging task. The temperature distribution within the cold storage is affected by many factors, such as the cold storage design, the layout of the refrigeration equipment, and the efficiency of the air circulation system. In particular, there are often temperature blind spots in the corners and edge areas of the cold storage. Due to poor cold air flow or lack of coverage by the refrigeration equipment, the temperature in these areas may be higher than the average temperature of the cold storage, resulting in the preservation effect in these areas being inferior to that in the center of the cold storage. In addition, frequent opening and closing of doors can also cause temperature fluctuations within the cold storage, further increasing the difficulty of maintaining a uniform low-temperature environment. Therefore, traditional cold storage has technical limitations in achieving uniform temperature control and cannot ensure that food throughout the cold storage is equally effectively preserved.

[0006] Impact on Food Quality: While low-temperature storage can extend the shelf life of food, prolonged low-temperature conditions can negatively impact food quality. Especially when temperatures drop below freezing, moisture in food freezes into ice crystals, which can damage cell structures. During the freezing and thawing process, the formation and melting of ice crystals can cause cell membranes to rupture, leading to structural changes. These changes not only affect the taste and texture of food but can also lead to a loss of nutrients. For example, frozen fruits and vegetables often become soft and mushy upon thawing, losing their flavor and potentially losing some nutrients.

[0007] In summary, traditional cold storage technology has significant limitations in extending food shelf life and cannot completely solve problems such as microbial suppression, food quality maintenance, and temperature control. These shortcomings have prompted the continuous development and innovation of cold storage technology to seek more efficient and reliable preservation solutions. Summary of the Invention

[0008] In order to improve the preservation effect of vegetables and fruits during transportation and storage, the present invention aims to provide a new cold storage that combines plasma sterilization technology and ozone refrigeration technology.

[0009] To achieve the above object, the technical solution adopted by the present invention is:

[0010] A fresh-keeping cold storage comprises a cold storage body 1, a plasma sterilization system 4, an ozone chilling system 5, a temperature control system, an air circulation system 6 and a central control system.

[0011] The cold storage body 1 is constructed of a spherical shell structure, which is a sandwich structure. The middle layer is made of a thermal insulation material, preferably polyurethane foam (PU foam). The inner and outer layers of the middle layer are made of stainless steel plates. Sealing strips are used at panel joints and door and window locations. A moisture-proof layer made of aluminum foil is added between the middle layer and the inner and outer layers. A shelf area 3 is provided inside the cold storage body 1.

[0012] The plasma sterilization system 4 can generate high-energy electrons, ions, free radicals, ozone, and ultraviolet rays through high-frequency, high-voltage electric fields or microwave-excited gases. These active substances destroy the cell walls, cell membranes, and DNA of microorganisms through physical and chemical reactions, thereby achieving a sterilization effect.

[0013] The ozone chilling system 5 can rapidly destroy the cell structures of bacteria, viruses and other microorganisms through ozone, a strong oxidant, thereby quickly killing these pathogens.

[0014] The temperature control system includes temperature sensors and ice temperature nozzles 2. Temperature sensors are located at various locations within the cold storage's shelf area 3 and at key locations throughout the cold storage to monitor ambient temperature in real time. Data is transmitted to a central control system. Based on feedback from the temperature sensors, the temperature control system precisely adjusts the temperature within the cold storage to ensure temperature stability.

[0015] The ice-temperature nozzle 2 includes a Laval nozzle, a liquid rocket engine injector and a Hall thruster buffer chamber d.

[0016] The Laval nozzle comprises a contraction section a, a throat b and an expansion section c.

[0017] The liquid rocket engine injector is located at the starting end of the contraction section a of the Laval nozzle.

[0018] The Hall thruster buffer chamber d is located at the end of the expansion section c of the Laval nozzle, and the two are separated by the maximum diameter.

[0019] The axis of the Laval nozzle, the axis of the liquid rocket engine injector, and the axis of the Hall thruster buffer chamber d coincide with each other.

[0020] Furthermore, air is introduced from the starting section of the contraction section a of the Laval nozzle.

[0021] Furthermore, the liquid rocket engine injector is a circular plate structure, and is provided with grid holes, wherein the outer diameter of the grid holes is equal to the diameter of the starting port of the contraction section a.

[0022] Furthermore, the grille holes have the same diameter, the central first-level array is a grille hole, and the surrounding annular arrays are arranged in layers from the inside to the outside. The grille holes in each layer of the annular array are evenly spaced, and the two adjacent layers of the annular arrays are arranged at equal intervals.

[0023] Furthermore, the design of the Laval nozzle is specifically as follows:

[0024] A rectangular coordinate system is established on the cross section passing through the axis of the Laval nozzle, with the center of the throat b as the origin of the coordinate system. The axis of the Laval nozzle is the x-axis, and the direction pointing to the end of the Hall thruster buffer cavity d is the positive direction of the x-axis. The direction perpendicular to the x-axis and at a 90-degree angle to the x-axis is the y-axis.

[0025] The inner wall of the contraction section a of the Laval nozzle is formed by the curve a around the axis of the Laval nozzle, the inner wall of the throat b of the Laval nozzle is formed by the curve b around the axis of the Laval nozzle, the inner wall of the expansion section c of the Laval nozzle is formed by the curve c around the axis of the Laval nozzle, and the inner wall of the Hall thruster buffer chamber d is formed by the curve d around the axis of the Hall thruster buffer chamber.

[0026] In the established rectangular coordinate system:

[0027] The trajectory equation of curve a is: x = -y 2 (-17.97≤x≤-1).

[0028] The trajectory equation of curve b is: 2 +(y-3) 2 =5(-1≤x<2).

[0029] The trajectory equation of curve c is:

[0030] The trajectory equation of curve d is: (x+19) 2 +y 2 =124(15≤x<28.95).

[0031] The arc trajectory equation of the nozzle of the Hall thruster buffer chamber d is: (x+30.74) 2 +(y-5.90) 2 =4(-28.95≤x≤-32.63).

[0032] In practical applications, the unit of measurement of x is determined as needed, that is, under the above trajectory equation, it can be proportionally enlarged or reduced as needed.

[0033] Furthermore, the Laval nozzle and liquid rocket engine injector are made of stainless steel.

[0034] The working principle of the above-mentioned thruster-based ice-temperature nozzle is as follows:

[0035] First of all, the overall structure of the cold storage ice temperature nozzle is a Laval nozzle structure. The Laval nozzle consists of three main parts: the contraction section a, the throat b and the expansion section c. In the contraction section a, the cross-sectional area of ​​the pipe gradually decreases. When the gas enters this section, the flow area gradually becomes smaller and the gas is compressed, resulting in an increase in its flow rate, and the pressure and temperature also increase accordingly. The throat b is the narrowest part of the nozzle, with a diameter of d2=1.53cm, and is located between the contraction section a and the expansion section c. At this position, the cross-sectional area of ​​the pipe reaches its minimum value. When the gas passes through the throat, the flow rate reaches the maximum. In the expansion section c, the cross-sectional area of ​​the pipe gradually increases. When the gas passes through this section, the flow rate of the gas gradually slows down, the pressure and temperature drop, and at the same time, the uniformity of the gas flow is further guaranteed.

[0036] Secondly, a liquid rocket engine injector was added at the beginning of the contraction section a of the cold storage's ice temperature nozzle. Through its precisely designed grid holes, the injector evenly ejects gas, ensuring that the gas is evenly distributed before entering the subsequent pipelines, avoiding localized overly strong or weak airflow. The injector design reduces turbulence and instability in the airflow, making the airflow more stable after passing through the injector.

[0037] Finally, a Hall thruster buffer chamber d was added to the end of the cold storage's ice-temperature nozzle. The Hall thruster buffer chamber d is a key component in the Hall effect propulsion system. Its primary function is to homogenize and stabilize gas flow, reducing turbulence and unevenness, and ensuring efficient and stable thruster operation. The main body of the Hall thruster buffer chamber d is typically a large container with ample internal space to allow sufficient time and space for gas to mix and homogenize after entering the buffer chamber. The cavity is a tapered tubular shape, which is well-suited to gas flow.

[0038] The air circulation system 6 includes air supply vents at the top of the cold storage, air outlets at the sides of the cold storage, and ventilation ducts formed between the shelves. Air circulation is achieved by supplying air from the top of the cold storage, flowing through the ducts between the shelves, and then out through the sides of the cold storage.

[0039] Furthermore, choose stainless steel or galvanized steel for ventilation ducts; install high-efficiency filters at air outlets to remove dust, particles, and impurities; install dehumidifiers at air outlets to prevent excessive humidity from affecting the quality of stored items; and install humidity sensors near shelves.

[0040] The central control system is used to perform overall control of the plasma sterilization system 4 , the ozone chilling system 5 , the temperature control system and the air circulation system 6 .

[0041] The beneficial effects of this invention include significantly improving the preservation of vegetables and fruits by combining plasma sterilization technology with ozone chilling technology. The cold storage's multi-layer insulation design and precise temperature control system ensure a stable and uniform environment within the cold storage. The optimized air circulation system ensures efficient and uniform air circulation, avoiding temperature and humidity blind spots. The entire system utilizes intelligent control for fully automated operation, improving efficiency and reducing manual intervention. The use of environmentally friendly materials and energy-saving designs reduces environmental impact and achieves energy conservation and environmental protection goals. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is a schematic diagram of a new type of cold storage for preserving vegetables and fruits according to the present invention;

[0043] Figure 2 This is a structural diagram of the ice temperature nozzle of the temperature control system of the present invention;

[0044] Figure 3 This is a schematic diagram of the sandwich structure of the outer shell of the novel vegetable and fruit fresh-keeping cold storage of the present invention;

[0045] Figure 4 This is a structural diagram of the plasma sterilizer for the novel cold storage for keeping vegetables and fruits fresh in the present invention;

[0046] Figure 5 This is a schematic diagram of the cold plasma sterilization process principle of fresh sweet chestnuts in the novel vegetable and fruit preservation cold storage of the present invention;

[0047] Figure 6 This is a schematic diagram of the ozone generation principle of the novel vegetable and fruit fresh-keeping cold storage of the present invention;

[0048] Figure 7 This is a high-end tubular structure of the ozone sterilization system of the novel vegetable and fruit fresh-keeping cold storage of the present invention;

[0049] Figure 8 This is a three-dimensional cross-sectional view of an ice-temperature nozzle based on a thruster after installation according to the present invention;

[0050] Figure 9 A side view of an ice-temperature nozzle based on a thruster after installation according to the present invention;

[0051] Figure 10 This is a front cross-sectional view of an ice-temperature nozzle based on a thruster after installation according to the present invention;

[0052] Figure 11 This is a schematic diagram of the various parts of an ice-temperature nozzle based on a thruster after installation according to the present invention;

[0053] Figure 12 This is a front view of a liquid rocket engine injector after installation of an ice-temperature nozzle based on a thruster according to the present invention;

[0054] In the figure: a contraction section; b throat; c expansion section; d Hall thruster buffer chamber.

[0055] In order to make the purpose, features, and advantages of the present invention more obvious and easy to understand, the present invention is further described below with reference to the accompanying drawings and in combination with specific embodiments, so that those skilled in the art can implement it with reference to the text of the description. The scope of protection of the present invention is not limited to the specific embodiments. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. DETAILED DESCRIPTION

[0056] (1) Cold storage body 1:

[0057] Cold storage body( Figure 1 ): Figure 1 It is a schematic diagram of a cold storage, showing the overall layout of the cold storage body, the design of the thermal insulation structure, and the relative positions of various system modules. The cold storage body 1 adopts a spherical shell structure, which is beneficial to saving materials, making the external wind field uniform, and increasing the stability and seismic performance of the overall structure. The spherical shell structure of the cold storage body 1 is a sandwich structure, and the material of the middle interlayer is a thermal insulation material to ensure the stability of the temperature inside the storage. For example, polyurethane foam (PU foam) has low thermal conductivity, excellent thermal insulation performance, good adhesion and weather resistance; the inner and outer layers of the middle interlayer are made of stainless steel plates, which have excellent corrosion resistance, high mechanical strength, and are easy to clean. They are suitable for the inner walls and floors of cold storage, especially in high humidity environments; sealing strips are used at the panel joints and door and window positions to prevent cold air from leaking out and improve the thermal insulation effect; a moisture-proof layer is added between the middle interlayer and the inner and outer layers. The moisture-proof layer is made of aluminum foil to prevent moisture from entering the thermal insulation layer and affecting the thermal insulation effect.

[0058] (2) Plasma sterilization system 4:

[0059] The plasma sterilization system 4 can generate high-energy electrons, ions, free radicals (such as oxygen and hydrogen radicals), ozone, and ultraviolet rays through high-frequency, high-voltage electric fields or microwave-excited gases. These active substances destroy the cell walls, cell membranes, and DNA of microorganisms through physical and chemical reactions, thereby achieving a sterilization effect.

[0060] use Figure 4 The cabinet-type low-temperature plasma sterilization equipment shown includes a cabinet body, a power supply built into the cabinet body, a transformer, an automatic lifting mechanism, a sterilization chamber and a control panel device.

[0061] Figure 5 The cold plasma sterilization process diagram for fresh sweet chestnuts is displayed. Research has shown that cold plasma has a significant sterilization effect on fresh sweet chestnuts.

[0062] Figure 6 The process diagram of ozone generation by electrolysis is shown, indicating the feasibility in principle.

[0063] The power supply provides total power support for the equipment and meets the voltage requirements of dielectric barrier discharge through a transformer. The power supply is fixed in the lower half of the cabinet.

[0064] The automatic lifting mechanism is fixed to the middle part of the cabinet and includes a motor, a lead screw, an X-shaped lifting frame, a slide rail, and a distance sensor element.

[0065] The sterilization chamber includes a chamber door with excellent sealing performance, a medium, an upper electrode, a fixed medium and a lower electrode; the upper electrode plate and the medium are fixed to the top of the cabinet through a suspension column, and the upper electrode plate and the lower electrode plate are made of stainless steel and are respectively connected to wires; the wires are connected to the power supply below through a wiring pipe.

[0066] The control panel device includes a touch screen, physical switches, and a control program, which is fixed to the upper right part of the cabinet. Behind the screen is the equipment mainboard, which has multiple built-in sterilization programs.

[0067] The sterilization chamber is sealed, including a chamber door with excellent sealing performance. The chamber door is sealed with upper and lower double rubber strips to achieve a high degree of sealing and prevent the excited plasma from overflowing out of the chamber.

[0068] The locking door device has two locking devices on the upper and lower parts. When the door is closed for sterilization, the internal structure of the equipment and the sterilization parameters are determined. The door will be automatically locked by the lock and is prohibited from being opened during the sterilization period to ensure the safety of sterilization. After the sterilization is completed, the locking device will automatically unlock. At this time, the door can be opened to take out fruits and vegetables.

[0069] The upper electrode plate and the upper part of the dielectric are fixed to the top of the cabinet by suspension columns. The upper and lower electrode plates are made of stainless steel and are connected to wires respectively; the wires are connected to the power supply below through wiring pipes; a pair of dielectrics (quartz material) are used to block discharge to generate plasma. The upper and lower dielectrics are respectively inside the electrodes. The electrode plate and the dielectric are fixed by a concave plate. The size of the concave plate is slightly smaller than the dielectric, which can play a fixing role.

[0070] The dielectric material for barrier discharge is quartz. Taking into account various factors such as cost, processing, maintenance, and replacement, technically speaking, the size of the dielectric material should be slightly larger than the electrode plate to ensure that there is no breakdown between the two electrodes.

[0071] The precision lifting mechanism is fixed to a platform in the center of the cabinet. The automatic lifting mechanism is program-controlled, with a motor driving a lead screw to raise the lower electrode plate via an X-shaped lifting frame and slide rails. The lower electrode plate is supported on the lifting platform by struts, creating space for the grounding wire. The grounding wire is placed in a flexible wiring conduit, connecting the lower electrode plate to the grounding device.

[0072] The lift platform is secured by a frame measuring 800mm long, 340mm wide, and 55mm high. The frame is designed to accommodate a motor. The lift platform's rails are symmetrical, with four rails, each 640mm long, running from top to bottom. The lead screw is connected to the rails by a crossbar measuring 300mm long and 15mm in diameter. The lead screw is 200mm in diameter, ensuring the desired sterilization height.

[0073] The lifting platform is made of stainless steel and lifts the lower concave plate through four pillars. Due to the need for discharge, wiring needs to be laid under the concave plate, and the cables are connected to the power supply below through a wiring duct.

[0074] A Mitsubishi servo motor model HF-KN23J-S100 and servo amplifier MR-JE-20A were selected. This motor meets the actual design requirements.

[0075] The load-bearing shaft has a diameter of 13.5 mm, a length of 335 mm, and is made of 45 steel. It is a key component of the lifting system.

[0076] The control panel device includes a multi-touch screen fixed to the upper right part of the cabinet. Behind the screen is the equipment motherboard with multiple sterilization programs built in. An equipment emergency stop button is fixed above the center of the screen.

[0077] Here's how it works:

[0078] First, the system excites the gas through a high-frequency, high-voltage electric field or microwaves, generating high-energy electrons, ions, free radicals (such as oxygen and hydrogen radicals), ozone, and ultraviolet rays. These active substances destroy the cell walls, cell membranes, and DNA of microorganisms through physical and chemical reactions, thereby achieving a sterilization effect.

[0079] Secondly, the sealing of the sterilization chamber ensures that the plasma does not leak out, and the chamber door will automatically lock during the sterilization process to ensure safety.

[0080] Subsequently, the automatic lifting mechanism adjusts the height of the electrode plate in the sterilization chamber so that the plasma can evenly cover the area to be treated, achieving the best sterilization effect.

[0081] Finally, the touch screen and control program on the control panel can set and monitor various parameters of the sterilization process, ensuring simple and convenient operation.

[0082] DBD cold plasma treatment system ( Figure 3 ): The DBD cold plasma treatment system is arranged in the storage area and operation area of ​​the cold storage, and evenly covers the food storage area through the distribution device. Figure 3 This is a schematic diagram of DBD cold plasma treatment of fresh sweet chestnuts, showing an application example of plasma treatment system in food preservation.

[0083] Schematic diagram of cold plasma sterilization process for fresh sweet chestnuts ( Figure 5 ): Gives examples of how ozone can preserve fruits and vegetables.

[0084] (3) Ozone chilling system 5:

[0085] Ozone disinfection is a highly effective and broad-spectrum disinfection method. As a strong oxidant, it rapidly destroys the cell structure of bacteria, viruses, and other microorganisms, thereby quickly killing these pathogens. Compared to traditional disinfectants such as chlorine, ozone sterilizes more quickly and is effective against a wide range of microorganisms, including bacteria, viruses, fungi, and spores. One significant advantage is that ozone decomposes into oxygen after disinfection, leaving no chemical residue, making it more environmentally friendly than many other disinfectants. Ozone also has a deodorizing function, effectively removing odors such as smoke and mold from the air. Therefore, we purchased a Fenghua 10G ozone disinfector model CYJ1910D-Y. The specific parameters are: Model: FH-CYJ1910D-Y; Name: Ozone disinfector; Ozone output: 10G / H; Cooling method: air cooling; Equipment size: 32x25x72 (CM); Gas source: air source; Rated voltage: 220V-50Hz; Rated power: 140W; Control mode: automatic and manual dual mode; Equipment material: all-steel box; Whole machine weight: 11KG; Usage area: ≤140m 2 .

[0086] This type of ozone disinfection machine adopts advanced intelligent design, with intelligent reservation and automatic timing functions. Users can set the running time according to actual needs to achieve unattended automatic operation. The machine body is equipped with high-quality food-grade stainless steel nozzles, non-magnetic all-steel shell, and universal rollers to ensure the convenience, safety and hygiene of the disinfection process. The core part adopts Figure 7 The high-end tubular ozone generator shown in the figure integrates advanced materials such as titanium alloy heat sink, 316L stainless steel electrode and crystal medium, which improves the durability and efficiency of the equipment. In addition, the design of this disinfection machine takes into account the special needs of different application scenarios, and is particularly suitable for use in cold storage, farms, hotels and other environments. In cold storage, it can effectively prevent food from being contaminated by microorganisms and extend its shelf life. This versatility makes the ozone disinfection machine an ideal choice for various commercial and industrial applications, combining high-efficiency disinfection capabilities and easy operation. Ozone generation principle diagram ( Figure 6 ): Demonstrates the principle of ozone production by electrolysis.

[0087] Ozone disinfection machine product parameters: shows the parameters of the Fenghua 10G ozone disinfection machine model CYJ1910D-Y. High-end tubular structure of the ozone sterilization system ( Figure 7 ): Demonstrates that high-end tubular generating units can achieve the aggregation of ozone gas, truly realizing multiple uses of one machine.

[0088] (4) Temperature control system:

[0089] Place temperature sensors in the shelf area. This ensures that the temperature inside the cold storage remains within the set range to safeguard the quality of stored items. Sensors are typically installed at several key locations in the cold storage shelf area to comprehensively monitor the temperature inside the cold storage. This includes the different heights of each shelf to ensure consistent temperatures across the entire shelf; the front and rear locations of the shelves to prevent local temperature deviations; and near the cold storage entrance and exit to monitor temperature changes. Regarding the type of temperature sensor, a semiconductor temperature sensor with a small size and high integration that can be used in conjunction with a wireless communication module can be used. Furthermore, the sensor needs to be connected to an intelligent monitoring system to transmit temperature data in real time via a wireless or wired network. Once the temperature exceeds the set range, the system automatically issues an alarm to notify management personnel.

[0090] The sensor material can be nickel-chromium alloy, which is often used to manufacture thermocouples (such as K-type thermocouples). It has good corrosion resistance and high-temperature oxidation stability, can maintain stable electrical properties in the range of extremely low temperature to high temperature, and can achieve long-term stable operation in extremely low temperature environments.

[0091] Structure such as Figure 2 As shown in the figure, after the gas passes through different parts of the ice temperature nozzle 2 pipe of the cold storage, it flows into the cold storage evenly and stably to achieve precise control of the temperature inside the cold storage, keeping the cold storage within the target temperature range of ±0.1℃, thereby improving the temperature control accuracy of the cold storage. The overall structure adopts Laval nozzle structure, made of stainless steel, and 10 nozzles are placed in each circle along the maximum diameter of the cold storage and 35cm below its height, as shown in the figure. Figure 1 A Hall thruster buffer chamber is added to the end of the nozzle to make the gas flow uniform and stable.

[0092] like Figures 8-12 A thruster-based ice-temperature nozzle comprises a contraction section a, a throat section b, an expansion section c of a Laval nozzle, a Hall thruster buffer chamber d, and a liquid rocket engine injector.

[0093] The liquid rocket engine injector is placed at the front end of the contraction section a of the Laval nozzle; the liquid rocket engine injector is a circular plate structure with multiple grille holes of the same diameter distributed thereon; the regional outer diameter of the grille holes is the same as the diameter of the starting end of the contraction section a, and the diameter is d1 = 8.48 cm; and the liquid rocket engine injector is coaxially arranged with the Laval nozzle.

[0094] The liquid rocket engine injector is arranged with grid holes, all with a diameter d0 = 0.75 cm. The central first-level array consists of a single grid hole, surrounded by a circular array. The second-level array has six grid holes, with a distance a1 = 1 cm from the center. The third-level array has 12 grid holes, with a distance a2 = 2 cm from the center. The fourth-level array has 18 grid holes, with a distance a3 = 3 cm from the center. The fifth-level array has 24 grid holes, with a distance a4 = 4 cm from the center.

[0095] The main body of the Hall thruster's buffer chamber d comprises a large, tapered channel, mounted at the rear end of the expansion section c. The maximum diameter of the Hall thruster's buffer chamber d and the expansion section c of the Laval nozzle define the boundary between them, with a diameter of d3 = 22.27 cm. The Hall thruster's buffer chamber d and the expansion section c are coaxial.

[0096] After installation, the corresponding axes of the liquid rocket engine injector, the contraction section a, the throat b, the expansion section c of the Laval nozzle, and the Hall thruster buffer chamber d coincide.

[0097] The design of the Laval nozzle is specifically as follows:

[0098] The diameter of the nozzle section a at the starting end is d1 = 8.48 (1 cm rounded corners)

[0099] The diameter of the narrowest part of the throat (section b) is d2 = 1.53

[0100] The widest diameter of nozzle section c is d3 = 22.27

[0101] Outlet diameter d4 = 7.80

[0102] Total length l = 41.24

[0103] Total diameter d = 31.80

[0104] A rectangular coordinate system is established on the cross section passing through the axis of the Laval nozzle, with the center of the throat b as the origin of the coordinate system. The axis of the Laval nozzle is the x-axis, and the direction pointing to the end of the Hall thruster buffer cavity d is the positive direction of the x-axis. The direction perpendicular to the x-axis and at a 90-degree angle to the x-axis is the y-axis.

[0105] The inner wall of the contraction section a of the Laval nozzle is formed by the curve a around the axis of the Laval nozzle, the inner wall of the throat b of the Laval nozzle is formed by the curve b around the axis of the Laval nozzle, the inner wall of the expansion section c of the Laval nozzle is formed by the curve c around the axis of the Laval nozzle, and the inner wall of the Hall thruster buffer chamber d is formed by the curve d around the axis of the Hall thruster buffer chamber.

[0106] In the established rectangular coordinate system:

[0107] The trajectory equation of curve a is: x = -y 2 (-17.97cm≤x≤-1cm)

[0108] The trajectory equation of curve b is: 2 +(y-3) 2 =5(-1cm≤x<2cm)

[0109] The trajectory equation of curve c is:

[0110] The trajectory equation of curve d is: (x+19) 2 +y 2 =124(15cm≤x<28.95cm)

[0111] The trajectory equation of the nozzle arc (major arc) of the Hall thruster buffer cavity d is: (x+30.74) 2 +(y-5.90) 2 =4(-28.95cm≤x≤-32.63cm);

[0112] (5) Air circulation system 6:

[0113] The schematic structure is as follows Figure 1 As shown in Figure 6. The air circulation system 6 includes air supply vents provided at the top of the cold storage, air outlets provided at the sides of the cold storage, and ventilation ducts formed between the shelves. An air circulation method is adopted in which air is supplied from the top to the interior of the cold storage, flows through the channels between the shelves, and is discharged from the sides of the cold storage. Low-temperature and corrosion-resistant materials, such as stainless steel or galvanized steel plates, are used for the ventilation ducts. A high-efficiency filter is installed at the air supply vent to remove dust, particles, and impurities from the air. A dehumidifier is installed at the air supply vent to prevent excessive humidity from affecting the quality of stored items. Humidity sensors are installed near the shelves.

[0114] Incorporating the design principles of aerospace engines, the vent and duct system within the cold storage ensures uniform air circulation, avoiding temperature dead zones. CFD (Computational Fluid Dynamics) simulations optimize vent positions and duct layout to ensure efficient and uniform air circulation.

[0115] The specific working steps of the fresh-keeping cold storage of the present invention are as follows: Vegetables are transported from farms or suppliers to the cold storage, typically using cold chain logistics to ensure they remain fresh during transportation. Before entering the cold storage, the vegetables undergo a preliminary quality inspection to ensure they are free of visible damage or decay. Once inside, the vegetables first pass through a plasma sterilization system 4, where plasma-generated active oxygen, free radicals, ultraviolet light, and other bactericidal factors effectively kill bacteria, viruses, and mold on the vegetable surfaces. The vegetables then enter an ozone chilling system 5, which further kills any remaining microorganisms and eliminates odors. This combination of ozone disinfection and chilling technology allows for even better preservation of vegetables at low temperatures. Ozone decomposes into oxygen over time, leaving no harmful residues. After sterilization and chilling, the vegetables are transferred to the cold storage's shelf area 3 for storage. Shelf area 3 uses temperature sensors to monitor and record temperature changes within the cold storage in real time. Temperature sensors are typically installed at different levels and locations to ensure a uniform and stable temperature within the cold storage. Through the intelligent monitoring system, managers can view temperature data in real time and adjust refrigeration equipment operations as needed to maintain optimal storage temperatures. Finally, based on market demand or order arrangements, the vegetables are shipped out on a first-in, first-out basis. Before shipment, the vegetables undergo another quality inspection to ensure their quality when delivered to customers.

[0116] In summary, the present invention provides a new type of vegetable and fruit fresh-keeping cold storage, which significantly improves the preservation effect and quality of food by combining advanced sterilization technology and temperature control technology, and has broad application prospects and market potential.

[0117] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A fresh-keeping cold storage, characterized in that: It includes a cold storage body (1), a plasma sterilization system (4), an ozone chilling system (5), a temperature control system, an air circulation system (6) and a central control system; The cold storage body (1) adopts a spherical shell structure; The plasma sterilization system (4) can generate high-energy electrons, ions, free radicals, ozone and ultraviolet rays through high-frequency and high-voltage electric fields or microwave-excited gases; these active substances destroy the cell walls, cell membranes and DNA of microorganisms through physical and chemical actions, thereby achieving a sterilization effect; The ozone chilling system (5) can rapidly destroy the cell structure of bacteria, viruses and other microorganisms through ozone, a strong oxidant, thereby quickly killing these pathogens; The temperature control system includes temperature sensors and ice temperature nozzles (2). The temperature sensors are arranged at different positions in the shelf area (3) of the cold storage and at various key positions of the cold storage to monitor the ambient temperature in real time; the data is transmitted to the central control system; The ice-temperature nozzle (2) includes a Laval nozzle, a liquid rocket engine injector and a Hall thruster buffer chamber (d); The Laval nozzle comprises a contraction section (a), a throat section (b) and a divergence section (c); The liquid rocket engine injector is located at the starting end of the contraction section (a) of the Laval nozzle; The Hall thruster buffer chamber (d) is located at the end of the expansion section (c) of the Laval nozzle, and the two are separated by the maximum diameter; The axis of the Laval nozzle, the axis of the liquid rocket engine injector, and the axis of the Hall thruster buffer chamber (d) coincide with each other; The air circulation system (6) includes an air supply port arranged on the top of the cold storage, an air outlet arranged on the side of the cold storage, and a ventilation duct formed between the shelves; an air circulation method is adopted in which air is supplied from the top to the interior of the cold storage, flows through the channels between the shelves, and is discharged from the side of the cold storage; The central control system is used to perform overall control of the plasma sterilization system (4), the ozone chilling system (5), the temperature control system and the air circulation system (6); The design of the Laval nozzle is specifically as follows: A rectangular coordinate system is established on the cross section passing through the axis of the Laval nozzle. The center of the throat (b) is set as the origin of the coordinate system. The axis of the Laval nozzle is the x-axis, and the direction pointing to the end of the Hall thruster buffer chamber (d) is the positive direction of the x-axis. The direction perpendicular to the x-axis and at a 90-degree angle to the x-axis is the y-axis. The inner wall of the convergent section (a) of the Laval nozzle is formed by curve a around the axis of the Laval nozzle, the inner wall of the throat (b) of the Laval nozzle is formed by curve b around the axis of the Laval nozzle, the inner wall of the divergent section (c) of the Laval nozzle is formed by curve c around the axis of the Laval nozzle, and the inner wall of the Hall thruster buffer chamber (d) is formed by curve d around the axis of the Hall thruster buffer chamber; In the established rectangular coordinate system: The trajectory equation of curve a is: x = -y 2 , -17.97≤x≤-1; The trajectory equation of curve b is: 2 +(y-3) 2 =5, -1≤x<2; The trajectory equation of curve c is: The trajectory equation of curve d is: (x+19) 2 +y 2 =124,15≤x<28.95; The arc trajectory equation of the nozzle of the Hall thruster buffer cavity (d) is: (x+30.74) 2 +(y-5.90) 2 =4, -28.95≤x≤-32.63; In practical applications, the unit of measurement of x is determined as needed, that is, under the above trajectory equation, it can be proportionally enlarged or reduced as needed.

2. A fresh-keeping cold storage according to claim 1, characterized in that: The spherical shell structure is a sandwich structure, and the material of the middle interlayer is a heat-insulating material; the inner and outer layers of the middle interlayer are made of stainless steel plates; sealing strips are used to seal the panel joints and the door and window positions; a moisture-proof layer is added between the middle interlayer and the inner and outer layers, and the moisture-proof layer is made of aluminum foil; a shelf area (3) is set inside the cold storage body (1).

3. A fresh-keeping cold storage according to claim 1, characterized in that: Air is introduced from the starting section of the convergence section (a) of the Laval nozzle.

4. A fresh-keeping cold storage according to claim 1, characterized in that: The liquid rocket engine injector is a circular plate structure, and is provided with grid holes. The outer diameter of the grid holes is equal to the diameter of the starting port of the contraction section (a).

5. A fresh-keeping cold storage according to claim 4, characterized in that: The grille holes have the same diameter, the center first-level array is a grille hole, and the surrounding annular arrays are arranged in layers from the inside to the outside. The grille holes in each layer of the annular array are evenly spaced, and the adjacent two layers of annular arrays are arranged at equal intervals.

6. A fresh-keeping cold storage according to claim 1, characterized in that: The Laval nozzle and the liquid rocket engine injector are made of stainless steel.

7. The fresh-keeping cold storage according to claim 1, characterized in that: Choose stainless steel or galvanized steel as the material for ventilation ducts; install high-efficiency filters at the air outlets to remove dust, particles and impurities in the air; install dehumidifiers at the air outlets to prevent excessive humidity from affecting the quality of stored items.

8. The fresh-keeping cold storage according to claim 1, characterized in that: Place humidity sensors near the shelves.

Images