A multi-temperature zone liquid nitrogen refrigerated truck and an environmental control method

Abstract

The present invention discloses a multi-temperature zone liquid nitrogen refrigerated truck and an environmental control method, which relates to the field of logistics fresh-keeping. It includes: a vehicle body, a carriage, and a liquid nitrogen cooling system. The carriage is divided into a freezing zone, a micro-freezing zone, and a refrigerated zone by a movable door. At the top of each temperature zone of the carriage, a first pressure sensor, a temperature sensor, and an atomizing nozzle are provided. The temperature sensor and the pressure sensor are respectively used to monitor the pressure and temperature conditions of the temperature zone where they are located. The liquid nitrogen cooling system includes a liquid nitrogen tank, a liquid nitrogen distribution pipeline, and a controller. The liquid nitrogen distribution pipeline connects the liquid nitrogen tank to the atomizing nozzles of each temperature zone of the carriage respectively. A second pressure sensor and a liquid level sensor are provided on the liquid nitrogen tank. The second pressure sensor and the liquid level sensor are respectively used to monitor the pressure in the liquid nitrogen tank and the remaining amount of liquid nitrogen. The present invention can achieve high-quality fresh-keeping of multi-category agricultural products and effectively extend the cruising range of pure electric refrigerated trucks.

Description

Technical Field

[0001] The present invention relates to the field of logistics fresh-keeping, and particularly relates to a multi-temperature zone liquid nitrogen refrigerated truck and an environmental control method. Background Art

[0002] In China's cold chain transportation market, road cold chain accounts for the main part, accounting for about 75% of the market share. With the development of China's cold chain logistics, the cold chain transportation structure has shifted from long-distance allocation transportation to medium and short-distance distributive transportation between urban areas, and the cold chain transportation of multiple varieties and small batches has become the main demand. At present, the refrigerated trucks in China only have a single storage environment and cannot realize the co-vehicle distribution of agricultural products with different fresh-keeping requirements for multiple varieties. Therefore, the phenomenon of non-full load frequently occurs during cold chain transportation, resulting in poor economy of cold chain transportation and serious waste of resources.

[0003] Traditional refrigerated trucks use a vapor compression refrigeration cycle to reduce the environmental temperature. The refrigeration temperature is generally not lower than -30°C. The lower the refrigeration temperature, the lower the refrigeration efficiency and the greater the energy consumption. Data shows that in medium-sized refrigerated transport vehicles, the energy consumption of the refrigeration system accounts for 50% of the total vehicle operation energy consumption. Driven by China's "dual carbon" goal, the development of electric vehicles has become the mainstream. The vapor compression refrigeration method will greatly reduce the cruising range of pure electric refrigerated trucks and is not conducive to the development direction of electric refrigerated trucks. Liquid nitrogen has a large cooling temperature range, has a certain modified atmosphere function, and does not consume electric energy, which can meet the requirements of high-quality fresh-keeping and long-distance transportation of pure electric refrigerated trucks. Summary of the Invention

[0004] Aiming at the deficiencies in the prior art, the present invention provides a multi-temperature zone liquid nitrogen refrigerated truck and an environmental control method, which can achieve high-quality fresh-keeping of multiple categories of agricultural products and effectively extend the cruising range of pure electric refrigerated trucks.

[0005] To achieve the above object, the technical solution of the present invention is as follows:

[0006] A multi-temperature zone liquid nitrogen refrigerated truck, comprising:

[0007] A vehicle body;

[0008] A carriage, which is arranged on the vehicle body. The carriage is divided into a freezing zone, a micro-freezing zone and a refrigerating zone by a movable door. At the top of each temperature zone of the carriage, a first pressure sensor, a temperature sensor and an atomizing nozzle are arranged. The temperature sensor and the pressure sensor are respectively used to monitor the pressure and temperature conditions of the corresponding temperature zone; and,

[0009] Liquid nitrogen cooling system, which includes a liquid nitrogen tank, a liquid nitrogen transportation and distribution pipeline, and a controller. The liquid nitrogen transportation and distribution pipeline connects the liquid nitrogen tank to the atomizing nozzles in each temperature zone of the carriage. A second pressure sensor and a liquid level sensor are provided on the liquid nitrogen tank. The second pressure sensor and the liquid level sensor are respectively used to monitor the pressure in the liquid nitrogen tank and the remaining amount of liquid nitrogen. The controller is used to control various electronic devices in the refrigerated vehicle.

[0010] For the multi-temperature zone liquid nitrogen refrigerated vehicle as described above, further, the electronic devices include a temperature sensor, a pressure sensor, a liquid level sensor, an exhaust valve, and an electric valve. The controller adjusts the opening and closing of the electric valve and the exhaust valve by monitoring the temperature and pressure conditions in each temperature zone to achieve temperature adjustment and pressure control in each temperature zone. A display screen is provided on the controller, which can display the pressure and liquid level of the liquid nitrogen tank and remind of the use and filling of liquid nitrogen.

[0011] For the multi-temperature zone liquid nitrogen refrigerated vehicle as described above, further, axial flow fans are provided in each temperature zone of the carriage to evenly distribute the environmental temperature in the carriage.

[0012] For the multi-temperature zone liquid nitrogen refrigerated vehicle as described above, further, the temperature in each temperature zone of the carriage can be set within a certain range. The temperature range of the freezing zone is below -18°C, the temperature range of the semi-freezing zone is -5°C to 0°C, and the temperature range of the refrigerated zone is 0°C to 6°C.

[0013] For the multi-temperature zone liquid nitrogen refrigerated vehicle as described above, further, a heat insulation layer is provided on the movable door to reduce heat transfer caused by temperature differences between temperature zones.

[0014] For the multi-temperature zone liquid nitrogen refrigerated vehicle as described above, further,

[0015] A unidirectional ventilation hole is provided above the movable door, and cold air flows from the freezing zone to the semi-freezing zone and from the semi-freezing zone to the refrigerated zone through the unidirectional ventilation hole;

[0016] An exhaust valve is also provided at the top of each temperature zone of the carriage, and the exhaust valve is used to release the gas pressure in each temperature zone.

[0017] For the multi-temperature zone liquid nitrogen refrigerated vehicle as described above, further, a third pressure sensor and an electric valve are sequentially provided in the liquid nitrogen transportation and distribution pipeline, and the liquid nitrogen is sent to the designated position by opening and closing the electric valve.

[0018] An environmental control method for a multi-temperature zone liquid nitrogen refrigerated vehicle, which is used for the multi-temperature zone liquid nitrogen refrigerated vehicle as described above, includes the following steps:

[0019] S1: Set the temperature values of each temperature zone to be T d , T w , T c ;

[0020] S2: Detect the real-time temperature value t of each temperature zone d , t w , t c ;

[0021] S3: Judge the real-time temperature of each temperature zone. If the t of each temperature zone d >T d ±△T℃ and t w >T w ±△T℃ and t c >T c ±△T℃, whether to start the rapid refrigeration mode. If so, open the electric valves V1, V2, V3 of the distribution pipeline and the exhaust valves of each temperature zone. The one-way ventilation holes are in the closed state until the temperature of each temperature zone reaches the set value and the pressure reaches the slightly positive pressure state, then close the electric valves and the exhaust valves. If not, start the conventional refrigeration mode, and then enter S4;

[0022] S4: Open the electric valves V1 of the liquid nitrogen distribution pipeline, and close the electric valves V2 and V3 to supply cold to the freezing zone. At this time, the one-way ventilation holes are opened, and only the exhaust valves of the refrigerated zone are opened, and then enter S5;

[0023] S5: Judge the real-time temperature and pressure of the freezing zone. If t d >T d ±△T℃, then after delaying for n seconds, return to S4. Otherwise, enter S6;

[0024] S6: If t w >T w ±△T℃, then close the electric valve V1. If the pressure in the freezing zone reaches the slightly positive pressure state, then close the one-way ventilation holes, open the electric valve V2, and after delaying for n seconds, re-judge the temperature of the semi-frozen zone. If t w ≤T w ±△T℃, then enter S7;

[0025] S7: If t c >T c ±△T℃, then close the electric valve V2. If the pressure reaches the slightly positive pressure state, close the exhaust valve and the one-way ventilation holes of the semi-frozen zone, open the electric valve V3, and after delaying for n seconds, re-judge the temperature of the semi-frozen zone. If t c ≤T c ±△T℃, then close the electric valve V3, close the exhaust valve of the refrigerated zone, and return to S5.

[0026] For the temperature control method of the multi-temperature zone liquid nitrogen refrigerated truck as described above, further, the slightly positive pressure state means that the pressure is 50-100 pa higher than the atmospheric pressure.

[0027] The temperature control method of the multi-temperature zone liquid nitrogen refrigerated truck as described above, further, the temperature deviation △T is between 0.5 and 2 °C.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] 1. Realize the multi-temperature zone preservation of the refrigerated truck, meet the transportation of agricultural products with different preservation requirements in the same vehicle, improve the loading rate of the refrigerated truck, and reduce resource waste.

[0030] 2. Adopt the liquid nitrogen cooling technology to greatly expand the preservation temperature zone range of the refrigerated truck, and the power consumption or fuel consumption is not increased during the transportation process, effectively extending the transportation distance of the refrigerated truck.

[0031] 3. The environmental control system of each temperature zone of the refrigerated truck has an energy-saving refrigeration mode, which can make full use of the low-temperature exhaust gas in the freezing zone to cool the semi-freezing zone, and use the low-temperature exhaust gas in the semi-freezing zone to cool the refrigerated zone, reducing the exhaust gas cold loss and liquid nitrogen loss.

[0032] 4. The environmental control system of each temperature zone of the refrigerated truck has a rapid refrigeration mode, which can quickly reduce the temperature of each temperature zone, realize the rapid freezing of food, and improve the food preservation quality. Description of the Drawings

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0034] Figure 1 It is a structural diagram of a multi-temperature zone liquid nitrogen refrigerated truck of the present invention;

[0035] Figure 2 It is a logic diagram of the environmental control method of a multi-temperature zone liquid nitrogen refrigerated truck of the present invention;

[0036] Figure 3 It is a logic diagram of the energy-saving refrigeration mode of the environmental control method of a multi-temperature zone liquid nitrogen refrigerated truck of the present invention;

[0037] In the figure: 100 - vehicle body; 200 - liquid nitrogen tank; 201 - controller; 202 - pressure sensor; 203 - liquid level sensor; 204 - electric valve; 205 - temperature zone pressure sensor; 206 - exhaust valve; 207 - temperature sensor; 208 - atomizing nozzle; 209 - axial flow fan; 300 - carriage; 301 - freezing zone; 302 - semi-freezing zone; 303 - refrigerated zone; 304 - movable door; 305 - single-phase ventilation hole. Detailed Embodiments

[0038] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0039] Embodiment:

[0040] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned accompanying drawings are used to distinguish similar objects, and do not necessarily need to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "comprising" and "having" in the embodiments of the present invention and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0041] In the description of the present invention, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. In addition, unless otherwise clearly specified and defined, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0042] See Figures 1 to 3 , Figure 1 is a structural diagram of a multi-temperature zone liquid nitrogen refrigerated truck of the present invention; Figure 2 is a logic diagram of an environmental control method for a multi-temperature zone liquid nitrogen refrigerated truck of the present invention; Figure 3 is a logic diagram of an energy-saving refrigeration mode of an environmental control method for a multi-temperature zone liquid nitrogen refrigerated truck of the present invention. The present invention provides a multi-temperature zone liquid nitrogen refrigerated truck and an environmental control method, which can achieve high-quality preservation of multiple categories of agricultural products and effectively extend the cruising range of a pure electric refrigerated truck.

[0043] Such as Figure 1As shown in the figure, a multi-temperature zone liquid nitrogen refrigerated truck includes a vehicle body 100, a carriage 300, and a liquid nitrogen cooling system. The carriage 300 is separated into a freezing zone 301, a micro-freezing zone 302, and a refrigerated zone 303 by a movable door 304. The temperatures of each temperature zone in the carriage 300 can be set within a certain range. The temperature range of the freezing zone 301 is below -18°C, the temperature range of the micro-freezing zone 302 is -5°C to 0°C, and the temperature range of the refrigerated zone 303 is 0°C to 6°C. In order to reduce heat transfer caused by temperature differences between temperature zones, a heat insulation layer (not shown in the figure) is provided on the movable door 304. The heat insulation material can be rubber and plastic cotton, aluminum silicate, polyurethane foam, etc. In order to monitor the environment inside the carriage, pressure sensors 205, temperature sensors 207, and exhaust valves 206 are provided at the top of each temperature zone in the carriage to monitor the pressure and temperature conditions in the corresponding temperature zone in real time.

[0044] The liquid nitrogen cooling system consists of a liquid nitrogen tank 200, a liquid nitrogen distribution pipeline, and a controller 201. A pressure sensor 202 and a liquid level sensor 203 are provided on the liquid nitrogen tank 200 to monitor the pressure inside the liquid nitrogen tank 200 and the remaining amount of liquid nitrogen respectively. A pressure sensor 202, an electric valve 204, and an atomizing nozzle 208 are sequentially arranged in the liquid nitrogen distribution pipeline to send liquid nitrogen to a designated position. The controller 201 is respectively connected to the temperature sensor 208, the pressure sensor 205, the liquid level sensor 203, the exhaust valve 206, and the electric valve 204. The controller 201 adjusts the opening and closing of the electric valve 204 and the exhaust valve 206 by monitoring the temperature and pressure conditions in each temperature zone to achieve temperature adjustment and pressure control in each temperature zone. In order to make the environmental temperature in each temperature zone inside the carriage more uniform, axial flow fans 209 can be provided in each temperature zone to enhance air flow. A display screen is provided on the controller to display the pressure and liquid level of the liquid nitrogen tank and remind of the use and filling of liquid nitrogen.

[0045] A unidirectional ventilation hole 305 is provided above the movable door. When the unidirectional ventilation hole is opened, cold air flows from the freezing zone 301 to the micro-freezing zone 302 and from the micro-freezing zone 302 to the refrigerated zone 303 through the unidirectional ventilation hole, reducing the cold loss caused by the direct discharge of low-temperature gas into the air. At this time, it is an energy-saving refrigeration mode.

[0046] As Figure 2 shown, the present invention also provides an environmental control method for a multi-temperature zone liquid nitrogen refrigerated truck, including the following steps:

[0047] S1: Set the temperature values of the freezing zone 301, the micro-freezing zone 302, and the refrigerated zone 303 to be T d , T w , T c ;

[0048] S2: Detect the real-time temperature values t of the freezing zone 301, the slightly frozen zone 302, and the refrigerated zone 303 d , t w , t c ;

[0049] S3: Judge the real-time temperature of each temperature zone. If the t of each temperature zone d >T d ±△T °C and t w >T w ±△T °C and t c >T c ±△T °C, where △T refers to the environmental temperature deviation, generally between 0.5 and 2 °C. Judge whether to start the rapid refrigeration mode. If so, each temperature independently controls its own environmental temperature and pressure, and judge whether the temperature and pressure of each temperature zone are less than or equal to the set values. If so, open the electric valves 204 and exhaust valves 206 corresponding to the temperature zones of the distribution pipeline. At this time, the one-way ventilation holes 305 are in the closed state. Until the temperature and pressure of each temperature zone reach the set values, the pressure set value refers to 50 - 100 pa higher than the atmospheric pressure. At this time, the pressure in the carriage is in a slightly positive pressure state, and the high-temperature air outside the carriage will not penetrate into the temperature zones. Then close the electric valves 204 and exhaust valves 206. If not, start the energy-saving refrigeration mode, and then enter S4;

[0050] As Figure 3 shown, it is an energy-saving refrigeration mode of an environmental control method for a multi-temperature zone refrigerated truck. In this mode, the exhaust gas from the low-temperature zone can be fully utilized to refrigerate the high-temperature zone, reducing cold energy waste.

[0051] S4: Open the electric valve V1 of the freezing zone of the liquid nitrogen distribution pipeline, close the electric valves V2 and V3 of the slightly frozen zone and the refrigerated zone. The liquid nitrogen cooling system cools the freezing zone 301. At this time, all the one-way ventilation holes 305 are in the open state, and only the exhaust valve of the refrigerated zone is open. Enter S5;

[0052] S5: Judge the real-time temperature and pressure of the freezing zone 301. If t d >T d ±△T °C, then after a delay of n seconds, return to S4. Otherwise, enter S6;

[0053] S6: If t w >T w ±△T °C, then close the electric valve V1. If the pressure in the freezing zone 301 reaches the slightly positive pressure state, then close the one-way ventilation hole 305, open the electric valve V2, and after a delay of n seconds, re-judge the temperature of the slightly frozen zone. If t w ≤T w ±△T °C, then enter S7;

[0054] S7: If t c >T cIf the temperature difference is ±△T℃, then close the electric valve V2. If the pressure reaches the slightly positive pressure state, close the exhaust valve 206 of the slightly frozen area 302 and the single-phase ventilation hole 305, open the electric valve V3, and after a delay of n seconds, re-judge the temperature of the slightly frozen area 302. If t c ≤T c is within ±△T℃, then close the electric valve V3, close the exhaust valve 305 of the refrigerated area 303, and return to S5.

[0055] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0056] The above embodiments are only for illustrating the technical concept and characteristics of the present invention, and their purpose is to enable ordinary technicians in the art to understand the content of the present invention and implement it accordingly, and cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the essence of the content of the present invention should be covered within the protection scope of the present invention.

Claims

1. A multi-temperature zone liquid nitrogen refrigerated vehicle, characterized in that, Comprising: Vehicle body; Compartment, which is arranged on the vehicle body. The compartment is divided into a freezing area, a slightly frozen area and a refrigerated area by movable doors. At the top of each temperature zone of the compartment, a first pressure sensor, a temperature sensor and an atomizing nozzle are arranged. The temperature sensor and the pressure sensor are respectively used to monitor the pressure and temperature conditions of the corresponding temperature zone; and, Liquid nitrogen cooling system, which includes a liquid nitrogen tank, a liquid nitrogen distribution pipeline and a controller. The liquid nitrogen distribution pipeline connects the liquid nitrogen tank with the atomizing nozzles of each temperature zone of the compartment respectively. A second pressure sensor and a liquid level sensor are arranged on the liquid nitrogen tank. The second pressure sensor and the liquid level sensor are respectively used to monitor the pressure in the liquid nitrogen tank and the remaining amount of liquid nitrogen. The controller is used to control various electronic devices in the refrigerated vehicle; the electronic devices include a temperature sensor, a pressure sensor, a liquid level sensor, an exhaust valve and an electric valve. The controller adjusts the opening and closing of the electric valve and the exhaust valve by monitoring the temperature and pressure conditions of each temperature zone to achieve temperature adjustment and pressure control of each temperature zone; a display screen is arranged on the controller, which can display the pressure and liquid level of the liquid nitrogen tank and remind of the use and filling of liquid nitrogen; The controller controls various electronic devices in the refrigerated vehicle according to the following method: S1: Set the temperature values of each temperature zone to T d , T w , T c ; S2: Detect the real-time temperature values t of each temperature zone d , t w , t c ; S3: Judge the real-time temperature of each temperature zone. When the temperature t of each temperature zone d >T d ±△T℃ and t w >T w ±△T℃ and t c >T c ±△T℃, then judge whether to start the rapid cooling mode. If so, open the electric valves V1, V2, V3 of the distribution pipeline and the exhaust valves of each temperature zone. The unidirectional ventilation holes are in the closed state until the temperature of each temperature zone reaches the set value and the pressure reaches the slightly positive pressure state, then close the electric valves and the exhaust valves; If not, start the conventional cooling mode, and then enter S4; S4: Open the electric valve V1 of the liquid nitrogen distribution pipeline, close the electric valves V2 and V3 to supply cold to the freezing area. At this time, the unidirectional ventilation hole is opened, and only the exhaust valve of the refrigerated area is opened, and enter S5; S5: Determine the real-time temperature and pressure in the freezing zone. If t d > T d ± ΔT °C, then after a delay of n seconds, return to S4; otherwise, proceed to S6; S6: If t w > T w ±△T °C, then close the electric valve V1. If the pressure in the freezing area reaches a slightly positive pressure state, then close the single-phase ventilation hole, open the electric valve V2, and after a delay of n seconds, re-judge the temperature in the semi-frozen area. If t w ≤T w ±△T °C, then proceed to S7; S7: If t c > T c ± ΔT °C, then close the electric valve V2. If the pressure reaches the slightly positive pressure state, close the exhaust valve of the slightly frozen area and the single-phase vent hole, open the electric valve V3, and after a delay of n seconds, re-judge the temperature of the slightly frozen area. If t c ≤ T c ± ΔT °C, then close the electric valve V3, close the exhaust valve of the refrigerated area, and return to S5.

2. The multi-temperature zone liquid nitrogen refrigerated truck according to claim 1, characterized in that, Axial flow fans are arranged in each temperature zone of the compartment to evenly the environmental temperature in the compartment.

3. The multi-temperature zone liquid nitrogen refrigerated vehicle according to claim 1, characterized in that, The temperature of each temperature zone in the compartment can be set within a certain range. The temperature range of the freezing area is below -18°C, the temperature range of the slightly frozen area is -5°C to 0°C, and the temperature range of the refrigerated area is 0°C to 6°C.

4. The multi-temperature zone liquid nitrogen refrigerated truck according to claim 1, wherein, A heat insulation layer is arranged on the movable door to reduce the heat transfer caused by the temperature difference between each temperature zone.

5. The multi-temperature zone liquid nitrogen refrigerated vehicle according to claim 1, wherein A unidirectional ventilation hole is arranged above the movable door, and cold air flows from the freezing area to the slightly frozen area and from the slightly frozen area to the refrigerated area through the unidirectional ventilation hole; Exhaust valves are also arranged at the top of each temperature zone of the compartment, and the exhaust valves are used to release the gas pressure of each temperature zone.

6. The multi-temperature zone liquid nitrogen refrigerated vehicle according to claim 1, characterized in that, A third pressure sensor and an electric valve are arranged in sequence in the liquid nitrogen distribution pipeline, and liquid nitrogen is sent to the designated position by opening and closing the electric valve.

7. The temperature control method of the multi-temperature zone liquid nitrogen refrigerated vehicle according to claim 1, characterized in that, The slightly positive pressure state means that the pressure is 50 - 100 Pa higher than the atmospheric pressure.

8. The temperature control method of the multi-temperature zone liquid nitrogen refrigerated vehicle according to claim 1, wherein, The temperature deviation △T is 0.5 - 2°C.

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