Fruit and Vegetable Pre-cooling System, Fruit and Vegetable Storage Equipment and Control Method

Abstract

The present invention provides a fruit and vegetable precooling system, a fruit and vegetable storage device and a control method, relating to the technical field of fruit and vegetable precooling, and solving the technical problem that the existing fruit and vegetable precooling storage has a slow temperature drop and uneven temperature in the storage after the temperature drop, seriously affecting the fresh-keeping effect of the stored fruits and vegetables. The fruit and vegetable precooling system includes an upper air return structure, a lower air return structure and an air duct structure. The upper air return structure is connected to the air duct structure. An upper air return channel is formed in the upper air return structure, and the air in the upper space of the fruit and vegetable storage can be sucked into the upper air return channel for heat exchange, and the cooled air can be sent out to the air duct structure. A lower air return channel is formed in the lower air return structure, and the air in the lower space of the fruit and vegetable storage can be sucked into the lower air return channel, and the air in the lower air return channel can be sent into the fruit and vegetable storage to be mixed with the cold air coming out of the air duct structure. Through the mutual mixing of the circulating air formed by the two air return structures, the heat exchange and circulation of the air in the fruit and vegetable storage are promoted, which is beneficial to uniform temperature and increased temperature drop speed.

Description

Technical Field

[0001] The invention relates to the technical field of fruit and vegetable precooling, and in particular to a fruit and vegetable precooling system, fruit and vegetable storage equipment and a control method. Background Art

[0002] Freshly picked fruits and vegetables are at high temperatures, and the bacteria on the surface multiply easily, causing them to rot. In addition, the lack of water during transportation causes them to shrivel, change color, and reduce their vitamin content. Fruits and vegetables are seriously damaged during transportation from the picking site to the destination, affecting their nutritional value and freshness. Therefore, it is particularly important to promote the preservation and storage of fruits and vegetables after picking.

[0003] In order to extend the shelf life and freshness of picked fruits and vegetables, temporary pre-cooling storage is added in the fields for storing fruits and vegetables to reduce the spoilage rate of fruits and vegetables during the waiting period.

[0004] Patent CN216644683U discloses a pressure differential precooling warehouse for cut flowers. A conventional precooling warehouse is transformed into a pressure differential precooling mode by forming a first directional airflow and a second directional airflow in the precooling warehouse. The air circulation in the entire precooling warehouse is accelerated by the suction effect of the cold air fan on the air in the directional air supply structure in combination with the directional suction effect of the axial flow fan, while ensuring that the second directional airflow after the first directional airflow passes through the axial flow fan and the cold air fan quickly completes sufficient cooling.

[0005] In traditional pre-cooling storage, the air cooler is placed on the top or side wall of the cold storage, which is not aesthetically pleasing and cannot achieve rapid cooling in the cold storage, resulting in uneven cooling. In addition, the refrigeration unit is externally mounted, increasing the risk of damage to the unit during transportation. Summary of the invention

[0006] The purpose of the present invention is to provide a fruit and vegetable precooling system, a fruit and vegetable storage device and a control method to solve the technical problem that the fruit and vegetable precooling storage in the prior art cools down slowly and the temperature of the cold storage after cooling is uneven, which seriously affects the preservation effect of stored fruits and vegetables. The various technical effects that can be produced by the preferred technical solution among the various technical solutions provided by the present invention are described in detail below.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] The fruit and vegetable precooling system provided by the present invention includes an upper air return structure, a lower air return structure, and an air duct structure. The upper air return structure is connected to the air duct structure. An upper air return channel is formed in the upper air return structure, which can suck the air in the upper space of the fruit and vegetable storage into the upper air return channel for heat exchange, and can send the cooled air to the air duct structure. A lower air return channel is formed in the lower air return structure, which can suck the air in the lower space of the fruit and vegetable storage into the lower air return channel, and can send the air in the lower air return channel into the fruit and vegetable storage to be mixed with the cold air coming out of the air duct structure.

[0009] As a further improvement of the present invention, the upper air return structure includes a cold air fan, a cooling structure, and an upper grille plate. An upper air return channel is formed between the upper grille plate and the inner wall of the fruit and vegetable storage. An upper air return opening communicating with the upper air return channel is formed on the upper grille plate. Both the cold air fan and the cooling structure are arranged in the upper air return channel, and the air outlet of the cold air fan is connected to the air inlet of the air duct structure.

[0010] As a further improvement of the present invention, the lower air return structure includes a differential pressure fan and a lower grille plate. A lower air return channel is formed between the lower grille plate and the inner wall of the fruit and vegetable storage. A lower air return opening communicating with the lower air return channel is formed in the lower region of the lower grille plate. The differential pressure fan is installed in the upper region of the lower grille plate.

[0011] As a further improvement of the present invention, a partition plate is arranged at the bottom of the upper air return channel. Both sides of the partition plate are fixedly connected to the inner wall of the fruit and vegetable storage and the upper grille plate respectively. Through the partition plate, the upper air return channel and the lower air return channel can be made not to communicate with each other.

[0012] As a further improvement of the present invention, the air outlet of the differential pressure fan is arranged to incline upwards.

[0013] As a further improvement of the present invention, there is an included angle between the axis of the air outlet of the differential pressure fan and the horizontal plane, and the included angle is 15 - 75°.

[0014] As a further improvement of the present invention, the air duct structure is installed on the top of the fruit and vegetable storage, and the air duct structure extends along the first length direction of the top of the fruit and vegetable storage, and the first length direction of the fruit and vegetable storage is consistent with the air outlet direction of the cold air fan.

[0015] As a further improvement of the present invention, the air duct structure includes at least two air ducts, and the air ducts are arranged at intervals along the second length direction of the top of the fruit and vegetable storage, and the second length direction of the top of the fruit and vegetable storage is set to be perpendicular to its first length direction.

[0016] As a further improvement of the present invention, the air duct includes an air duct housing, a gas flow channel is formed inside the air duct housing, an installation part for connecting with the top of the fruit and vegetable storage is formed at the top of the air duct housing, air outlet holes are formed on the periphery of the air duct housing, and the air in the gas flow channel can flow out through the air outlet holes into the interior of the fruit and vegetable storage.

[0017] As a further improvement of the present invention, the fruit and vegetable precooling system further includes a condensing unit, and the condensing unit is placed inside the fruit and vegetable storage.

[0018] As a further improvement of the present invention, a baffle structure is arranged in the lower air return channel, the baffle structure is connected to the inner wall of the fruit and vegetable storage, and the lower air return channel can be divided into an air return channel body area and a condensing unit installation area through the baffle structure, the lower air return opening is communicated with the air return channel body area, and the air in the air return channel body area can be sent out through the differential pressure fan.

[0019] As a further improvement of the present invention, the fruit and vegetable precooling system further includes a temperature detection structure, and the temperature detection structure is installed inside the fruit and vegetable storage.

[0020] The present invention provides a fruit and vegetable storage device, including a fruit and vegetable storage and a fruit and vegetable precooling system, wherein, the fruit and vegetable precooling system is the above-mentioned fruit and vegetable precooling system, and the fruit and vegetable precooling system is arranged inside the fruit and vegetable storage.

[0021] The present invention also provides a control method for a fruit and vegetable precooling system, used to control the above-mentioned fruit and vegetable precooling system, the upper air return structure includes a cold air fan, the lower air return structure includes a differential pressure fan, and the method includes:

[0022] Obtain the lowest temperature inside the fruit and vegetable storage;

[0023] Compare the lowest temperature inside the fruit and vegetable storage with the preset temperature of fruits and vegetables suitable for storage;

[0024] Control the operation of the cold air fan and the differential pressure fan according to the comparison result.

[0025] As a further improvement of the present invention, the preset temperature of fruits and vegetables includes a first preset temperature and a second preset temperature, wherein, the first preset temperature is less than the second preset temperature.

[0026] As a further improvement of the present invention, the controlling the operation of the cold air fan and the differential pressure fan according to the comparison result includes:

[0027] If the lowest temperature inside the fruit and vegetable storage is greater than the second preset temperature, then control the cold air fan and the differential pressure fan to start;

[0028] If the lowest temperature inside the fruit and vegetable storage is between the first preset temperature and the second preset temperature, control the cold air blower to start, and control the operation of the differential pressure blower according to the difference between the highest temperature and the lowest temperature inside the fruit and vegetable storage.

[0029] As a further improvement of the present invention, the controlling the operation of the cold air blower and the differential pressure blower according to the comparison result further includes:

[0030] If the lowest temperature inside the fruit and vegetable storage is less than the first preset temperature, control the cold air blower, and control the operation of the differential pressure blower according to the difference between the highest temperature and the lowest temperature inside the fruit and vegetable storage.

[0031] As a further improvement of the present invention, the controlling the operation of the differential pressure blower according to the difference between the highest temperature and the lowest temperature inside the fruit and vegetable storage includes:

[0032] Obtain the highest temperature and the lowest temperature inside the fruit and vegetable storage to get the difference between the highest temperature and the lowest temperature;

[0033] If the difference between the highest temperature and the lowest temperature inside the fruit and vegetable storage is greater than the preset difference, control the differential pressure blower to start;

[0034] If the difference between the highest temperature and the lowest temperature inside the fruit and vegetable storage is less than or equal to the preset difference, control the differential pressure blower to close.

[0035] The fruit and vegetable precooling system provided by the present invention includes an upper air return structure, a lower air return structure and an air duct structure. The upper air return structure is connected to the air duct structure. An upper air return channel is formed inside the upper air return structure, and a lower air return channel is formed inside the lower air return structure. The upper air return structure can suck the air in the upper space of the fruit and vegetable storage into the upper air return channel for heat exchange, and can send the cooled air to the air duct structure, and send the cold air into the fruit and vegetable storage through the air duct structure; under the action of the lower air return structure, the air in the lower space of the fruit and vegetable storage can be sucked into the lower air return channel and can be sent back to the precooling storage again to be mixed with the cold air coming out of the air duct structure for cooling. The circulating air in the two air return structures is mixed with each other, promoting the heat exchange and circulation of the air inside the fruit and vegetable storage, which is beneficial to the temperature uniformity and improves the cooling speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0037] Figure 1It is a schematic diagram of the overall structure of the fruit and vegetable storage equipment provided by an embodiment of the present invention;

[0038] Figure 2 It is a front view of the fruit and vegetable storage equipment provided by an embodiment of the present invention;

[0039] Figure 3 It is a schematic diagram of the air flow trajectory inside the fruit and vegetable storage provided by an embodiment of the present invention;

[0040] Figure 4 It is a schematic diagram of the structure of the fruit and vegetable storage equipment provided by another embodiment of the present invention;

[0041] Figure 5 It is a schematic diagram of the structure of an air outlet hole of the air duct provided by an embodiment of the present invention;

[0042] Figure 6 It is another schematic diagram of the structure of the air outlet hole of the air duct provided by an embodiment of the present invention;

[0043] Figure 7 It is a cross-sectional schematic diagram of three air ducts provided by an embodiment of the present invention;

[0044] Figure 8 It is a schematic flow chart of the control method of the fruit and vegetable precooling system provided by an embodiment of the present invention;

[0045] Figure 9 It is a control flow chart of the cold air fan and the differential pressure fan provided by an embodiment of the present invention.

[0046] Reference numerals: 1, cold air fan; 2, air duct structure; 3, evaporator; 4, differential pressure fan; 5, upper air return opening; 6, lower air return opening; 7, condensing unit; 8, fruit and vegetable storage; 9, air outlet hole; 10, solar photovoltaic panel; 11, energy storage battery; 12, partition board; 13, baffle structure. Detailed implementation manners

[0047] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be described in detail below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other implementation manners obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope protected by the present invention.

[0048] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0049] In the description of the present invention, it should also be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" 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. 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.

[0050] The technical solution of the present invention will be specifically described below with reference to the drawings.

[0051] See Figures 1 to 7 , the present invention provides a fruit and vegetable precooling system, including an upper air return structure, a lower air return structure, and an air duct structure 2. The upper air return structure is connected to the air duct structure 2. An upper air return channel is formed in the upper air return structure, and the air in the upper space of the fruit and vegetable storage 8 (also known as the precooling storage) can be sucked into the upper air return channel for heat exchange, and the cooled air can be sent out to the air duct structure 2; a lower air return channel is formed in the lower air return structure, and the air in the lower space of the fruit and vegetable storage 8 can be sucked into the lower air return channel, and the air in the lower air return channel can be sent into the fruit and vegetable storage 8 to be mixed with the cold air coming out of the air duct structure 2.

[0052] Specifically, the upper air return structure in this embodiment includes a cold air fan 1, a cooling structure (which can be an evaporator 3), and an upper grille plate. An upper air return channel is formed between the upper grille plate and the inner surface of the side wall of the fruit and vegetable storage 8. An upper air return opening 5 communicating with the upper air return channel is formed on the upper grille plate. The cold air fan 1 and the cooling structure are both arranged in the upper air return channel, and the air outlet of the cold air fan 1 is connected to the air inlet of the air duct structure 2.

[0053] The lower air return structure includes a differential pressure fan 4 and a lower grille plate. An air return channel is formed between the lower grille plate and the inner surface of the side wall of the fruit and vegetable storage 8. An air return opening 6 communicating with the air return channel is formed in the lower region of the lower grille plate, and the differential pressure fan 4 is installed in the upper region of the lower grille plate. A partition plate 12 is provided at the bottom of the upper air return channel. The two sides of the partition plate 12 are respectively fixedly connected to the side wall of the fruit and vegetable storage 8 and the bottom of the upper grille plate, so that the upper air return channel and the lower air return channel are not communicated with each other through the partition plate 12. The differential pressure fan 4 can suck out the hot air in the lower part of the fruit and vegetable storage 8, which will promote the replenishment of cold air in the upper part to promote the cooling between fruits and vegetables, and prevent the cold air from only staying on the surface of the fruits and vegetables without cold air circulation in the gaps between the fruits and vegetables. The function of the differential pressure fan 4 is to promote the circulation and flow of air in the entire fruit and vegetable storage 8, which is beneficial to the heat exchange between the air.

[0054] As an optional implementation manner of the embodiment of the present invention, the air outlet of the differential pressure fan 4 is inclined upward. Further, there is an included angle α between the axis of the air outlet of the differential pressure fan 4 and the horizontal plane, and the included angle α is 15-75°. This included angle can be adjusted according to the specific actual situation and the use effect of the air duct structure 2. The purpose of such an inclined setting is to prevent the air blown out by the differential pressure fan 4 from being horizontal, but to blow it upward, as Figure 3 shown. Such a setting can not only mix the air blown out by the differential pressure fan 4 with the cold air scattered from the air duct, promote the heat exchange of the air in the fruit and vegetable storage 8, be beneficial to the uniformity of the temperature and improve the cooling speed, but also a part of the air blown out by the differential pressure fan 4 directly enters the lower end of the evaporator 3 through the upper air return opening 5 for refrigeration, and then is blown into the pre-cooling storage by the cold air fan 1 and the air duct structure 2. The differential pressure fan 4 operates intermittently, and the differential pressure fan 4 can play a role in promoting the air return of the pre-cooling storage and uniforming the temperature.

[0055] The air duct structure 2 is installed on the top of the fruit and vegetable storage 8, and the air duct structure 2 extends along the first length direction of the top of the fruit and vegetable storage 8. The first length direction of the fruit and vegetable storage 8 is consistent with the air outlet direction of the cold air fan 1. The function of the air duct structure 2 is not to allow the outside air to flow into the fruit and vegetable storage 8, but to complete the circulation of the air in the fruit and vegetable storage 8, and has a guiding and transporting effect on the cold air.

[0056] The air duct structure 2 includes at least two air ducts, and the air ducts are arranged at intervals along the second length direction of the top of the fruit and vegetable storage 8. The second length direction of the top of the fruit and vegetable storage 8 is set perpendicular to its first length direction. The air duct includes an air duct housing, a gas flow channel is formed in the air duct housing, an installation part for connecting with the top of the fruit and vegetable storage 8 is formed at the top of the air duct housing, and air outlet holes 9 are opened on the peripheral side of the air duct housing. The air in the gas flow channel can flow out through the air outlet holes 9 into the interior of the fruit and vegetable storage 8.

[0057] The cold air refrigerated by the evaporator 3 enters the air duct after being sucked by the cold air fan 1. The air duct extends from one end of the fruit and vegetable storage 8 to the other end. The cold air flows along the air duct. The combination of the cold air fan 1 and the air duct is used to complete the transportation and distribution of the cold air, which is beneficial to the cold air being transported over a longer distance and serves the purpose of guiding the air outlet.

[0058] Among them, Figure 5 the air duct of Figure 6 has evenly distributed openings and the sizes of all the air outlet holes 9 are the same, while

[0059] for Figure 7 the air duct of

[0060] the air outlet holes 9 adopt the form of being larger near and smaller far away, that is, the air outlet holes 9 become smaller from the end close to the cold air fan 1 to the end far away from the cold air fan 1. The use of different air duct opening types is mainly to promote the even distribution of the air volume of each air outlet hole 9 in the air duct, so that the fruit and vegetable storage 8 maintains uniform air outlet and temperature reduction in the first length direction, and improves the temperature reduction speed and temperature uniformity of the pre-cooling storage.

[0061] Inside the fruit and vegetable storage 8, the upper air return structure and the lower air return structure form two-way air circulation. One way is the cold air cooled by the evaporator 3, and the other way is the air that promotes the air circulation inside the fruit and vegetable storage 8 under the action of the differential pressure fan. The two-way circulating air is mixed with each other to promote the temperature reduction and temperature uniformity of the air inside the fruit and vegetable storage 8.

[0062] When the pre-cooling of the fruit and vegetable storage 8 starts, the cold air fan 1 will suck the air inside the fruit and vegetable storage 8 through the upper air return opening 5 to the evaporator 3 in the upper air return channel, cool it under the action of the evaporator 3, and send the cold air into the fruit and vegetable storage 8 through the cold air fan 1 and the air duct structure 2 on the upper side of the fruit and vegetable storage 8; under the action of the differential pressure fan 4, the initial hot air at the lower part of the fruit and vegetable storage 8 is sucked out of the pre-cooling storage through the lower air return opening 6, sent to the differential pressure fan 4 through the lower air return channel, and then sent back into the fruit and vegetable storage 8 again through the differential pressure fan 4. A part of the air sent back into the fruit and vegetable storage 8 through the differential pressure fan 4 will be mixed with the cold air scattered by the air duct structure 2 to complete the temperature reduction, and at the same time, a part of it will directly enter the lower end of the evaporator 3 through the upper air return opening 5 after leaving the differential pressure fan 4 for temperature reduction. The existence of the differential pressure fan 4 promotes the air circulation inside the pre-cooling storage and improves the temperature reduction speed.

[0063] The fruit and vegetable precooling system further includes a condensing unit 7. Considering that in the traditional fruit and vegetable storage 8, the air cooler is placed on the top or side wall of the cold storage, which is not aesthetically pleasing and increases the risk of damage to the unit during transportation. In this embodiment, the condensing unit 7 is placed inside the fruit and vegetable storage 8.

[0064] As Figure 4 shown, a baffle structure 13 is arranged in the lower return air duct. The baffle structure 13 is connected to the inner wall of the fruit and vegetable storage 8. Through the baffle structure 13, the lower return air duct can be divided into a return air duct body area and a condensing unit 7 installation area. The lower return air outlet 6 is connected to the return air duct body area, and the air in the return air duct body area can be sent out through the differential pressure fan 4. The condensing unit 7 installation area is used to place the condensing unit 7.

[0065] The original condensing unit 7 of the fruit and vegetable storage 8 was placed outside the fruit and vegetable storage 8, and the air cooler fan 1 was directly hung on the wall inside the fruit and vegetable storage 8 for blowing. In this embodiment, the overall layout of the original fruit and vegetable storage 8 is adjusted. Both the condensing unit 7 and the air cooler fan 1 are placed inside the fruit and vegetable storage 8 and separated from the storage area of the fruit and vegetable storage 8 by an upper grille plate and a lower grille plate, realizing the compact, aesthetic and concealed air outlet of the overall structure.

[0066] In addition, the fruit and vegetable precooling system further includes a temperature detection structure, which is installed inside the fruit and vegetable storage 8. The temperature detection structure in this embodiment uses a temperature sensor, mainly to be able to accurately convey the temperature inside the fruit and vegetable storage 8 in real time. The number of temperature sensors is mainly based on the temperature monitoring range that can cover the entire fruit and vegetable storage 8 (mainly the storage area). The position of the temperature sensor can be selected in the area where the goods are stacked, as long as the temperature of the storage area can be monitored.

[0067] Based on a general inventive concept, an embodiment of the present invention also provides a control method for a fruit and vegetable precooling system. Figure 8 is a schematic flow chart provided by an embodiment of the control method of the fruit and vegetable precooling system of the present invention. Referring to Figure 8 , the control method of the fruit and vegetable precooling system of the present invention can be applied to the fruit and vegetable precooling system described in any of the above embodiments, and may include the following steps:

[0068] Step S21, obtaining the lowest temperature T inside the fruit and vegetable storage 8;

[0069] Step S22, comparing the lowest temperature inside the fruit and vegetable storage 8 with the preset temperature of the fruit and vegetable suitable for storage;

[0070] Step S23, controlling the operation of the air cooler fan 1 and the differential pressure fan 4 according to the comparison result.

[0071] The preset temperatures of the fruits and vegetables described above include a first preset temperature t1 and a second preset temperature t2, where the first preset temperature is less than the second preset temperature.

[0072] In the embodiment of the present invention, in step S23, controlling the operation of the cold air blower 1 and the differential pressure blower 4 according to the comparison result includes:

[0073] If the lowest temperature T inside the fruit and vegetable storage 8 is greater than the second preset temperature t2, then control the cold air blower 1 and the differential pressure blower 4 to turn on;

[0074] If the lowest temperature T inside the fruit and vegetable storage 8 is between the first preset temperature t1 and the second preset temperature t2, then control the cold air blower 1 to turn on, and control the operation of the differential pressure blower 4 according to the difference ΔT between the highest temperature and the lowest temperature inside the fruit and vegetable storage 8;

[0075] If the lowest temperature inside the fruit and vegetable storage 8 is less than the first preset temperature, then control the cold air blower 1 to turn off, and control the operation of the differential pressure blower 4 according to the difference ΔT between the highest temperature and the lowest temperature inside the fruit and vegetable storage 8.

[0076] Optionally, controlling the operation of the differential pressure blower 4 according to the difference between the highest temperature and the lowest temperature inside the fruit and vegetable storage 8 in the above steps includes:

[0077] Obtain the highest temperature and the lowest temperature inside the fruit and vegetable storage 8 to get the difference ΔT between the highest temperature and the lowest temperature; multiple temperature sensors are arranged inside the fruit and vegetable storage 8, and the highest temperature and the lowest temperature of the fruit and vegetable storage 8 are obtained according to the temperature information detected by the multiple temperature sensors;

[0078] If the difference ΔT between the highest temperature and the lowest temperature inside the fruit and vegetable storage 8 is greater than the preset difference, then control the differential pressure blower 4 to turn on;

[0079] If the difference ΔT between the highest temperature and the lowest temperature inside the fruit and vegetable storage 8 is less than or equal to the preset difference, then control the differential pressure blower 4 to turn off.

[0080] The preset difference in this embodiment can be set to 1°C.

[0081] The cold air blown out by the cold air blower enters the fruit and vegetable storage 8 through the air outlet holes 9 at the air duct structure 2. Fruit and vegetable packing boxes are stacked inside the fruit and vegetable storage 8. Under normal refrigeration conditions, the cold air blown out by the cold air blower floats on the surface of the fruits and vegetables, and it is difficult to cool the fruits and vegetables through the gaps between the fruit and vegetable packing boxes. Therefore, the temperature drop at the fruit and vegetable stacking place is slow, and the internal temperature of the pre-cooling storage compartment is uneven.

[0082] In this embodiment, at the beginning of precooling, since the temperature in the fruit and vegetable storage 8 is relatively high, the cold air blower 1 and the differential pressure blower 4 are started simultaneously. The lower return air inlet 6 below the differential pressure blower 4 sucks out the relatively high-temperature air at the lower part of the fruits and vegetables in the fruit and vegetable storage 8 from the storage area of the fruit and vegetable storage 8. Most of the sucked hot air will be discharged into the fruit and vegetable storage 8 again through the differential pressure blower 4 and mixed with the cold air blown out by the cold air blower 1 to accelerate the temperature uniformity and heat exchange in the fruit and vegetable storage 8. At the same time, a part of the hot air will directly flow from the upper return air inlet 5 at the lower end of the cold air blower 1 to the upper return air duct, and after being cooled by the evaporator 3, it will finally be blown into the fruit and vegetable storage 8 by the cold air blower 1 through the duct structure 2. The presence of the differential pressure blower 4 accelerates the air circulation in the fruit and vegetable storage 8, achieving the purpose of accelerating cooling and making the space temperature uniform. The schematic diagram of the cold air flow is as Figure 3 shown. When the temperature in the fruit and vegetable storage 8 drops to the storage temperature range of the fruits and vegetables, the cold air blower 1 is turned on, but the start of the differential pressure blower 4 depends on conditions, as Figure 9 shown, which is a specific adjustment and control process of the cold air blower 1 and the differential pressure blower 4 in the fruit and vegetable precooling system. The cold air blower 1 and the differential pressure blower 4 work according to the temperature in the fruit and vegetable storage 8.

[0083] When the fruit and vegetable storage 8 starts refrigeration, it is necessary to monitor the temperature in the fruit and vegetable storage 8. When the lowest temperature T detected in the fruit and vegetable storage 8 is greater than the second preset temperature t2 (the maximum temperature suitable for fruit and vegetable storage), the cold air blower 1 and the differential pressure blower 4 will be turned on simultaneously to refrigerate the fruit and vegetable storage 8. After refrigeration for a period of time, when the temperature in the pre-cooling storage is within the optimal storage temperature range of the fruits and vegetables, that is, t1 < T < t2 (or t1 ≤ T ≤ t2), at this time, the rotation speed of the cold air blower 1 can be reduced and the temperature uniformity in the fruit and vegetable storage 8 can be detected. When the difference ΔT between the highest temperature and the lowest temperature in the fruit and vegetable storage 8 is > 1 °C, the differential pressure blower 4 continues to be in the on state, otherwise the differential pressure blower 4 is turned off. When the lowest temperature in the pre-cooling storage reaches the first preset temperature t1 (the minimum temperature suitable for fruit and vegetable storage), the cold air blower 1 is turned off, and at the same time, the temperature uniformity in the pre-cooling storage is detected, and the differential pressure blower 4 is turned on or off according to the temperature uniformity.

[0084] In addition, the present invention also provides a fruit and vegetable storage device, Figure 1 and Figure 2 are the schematic structural diagrams of the fruit and vegetable storage device of the present invention.

[0085] Referring to Figure 1 , the fruit and vegetable storage device may include a fruit and vegetable storage 8 and a fruit and vegetable precooling system. Among them, the fruit and vegetable precooling system is the fruit and vegetable precooling system mentioned above, and the fruit and vegetable precooling system is arranged in the fruit and vegetable storage 8.

[0086] As Figure 4As shown in the figure, a solar photovoltaic panel 10 is further provided at the top of the fruit and vegetable storage 8 in this embodiment. The supporting energy storage battery 11 is located in the installation box of the condensing unit 7. The solar photovoltaic panel 10 can convert solar energy into electrical energy and store it in the energy storage battery 11. When the power supply is insufficient or there is a power outage, the electrical energy stored in the energy storage battery 11 can be used to supply power to electrical equipment such as the fan, the evaporator 3, and the condenser, so as to complete the required normal work, meet the refrigeration demand when the power supply is insufficient, and improve the emergency response ability of the fruit and vegetable storage 8.

[0087] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A fruit and vegetable precooling system, characterized in that, It includes an upper air return structure, a lower air return structure and an air duct structure. The upper air return structure is communicated with the air duct structure. An upper air return channel is formed in the upper air return structure, and the air in the upper space of the fruit and vegetable storage can be sucked into the upper air return channel for heat exchange, and the cooled air can be sent out to the air duct structure. An lower air return channel is formed in the lower air return structure, and the air in the lower space of the fruit and vegetable storage can be sucked into the lower air return channel, and the air in the lower air return channel can be sent into the fruit and vegetable storage to be mixed with the cold air coming out of the air duct structure. The upper air return structure includes a cold air fan, a cooling structure and an upper grille plate. An upper air return channel is formed between the upper grille plate and the inner wall of the fruit and vegetable storage. An upper air return opening communicated with the upper air return channel is formed on the upper grille plate. The cold air fan and the cooling structure are both arranged in the upper air return channel, and the air outlet of the cold air fan is communicated with the air inlet of the air duct structure. The lower air return structure includes a differential pressure fan and a lower grille plate. An lower air return channel is formed between the lower grille plate and the inner wall of the fruit and vegetable storage. A lower air return opening communicated with the lower air return channel is formed in the lower region of the lower grille plate. The differential pressure fan is installed in the upper region of the lower grille plate. The air duct structure is installed on the top of the fruit and vegetable storage and extends along the first length direction of the top of the fruit and vegetable storage. The first length direction of the fruit and vegetable storage is consistent with the air outlet direction of the cold air fan.

2. The fruit and vegetable precooling system according to claim 1, characterized in that, A partition plate is arranged at the bottom of the upper air return channel. The two sides of the partition plate are respectively fixedly connected with the inner wall of the fruit and vegetable storage and the upper grille plate. The partition plate can make the upper air return channel and the lower air return channel not communicate with each other.

3. The fruit and vegetable precooling system according to claim 1, characterized in that, The air outlet of the differential pressure fan is arranged obliquely upward.

4. The fruit and vegetable precooling system according to claim 1, characterized in that, There is an included angle between the axis of the air outlet of the differential pressure fan and the horizontal plane, and the included angle is 15-75°.

5. The fruit and vegetable precooling system according to claim 1, characterized in that, The air duct structure includes at least two air ducts, and the air ducts are arranged at intervals along the second length direction of the top of the fruit and vegetable storage. The second length direction of the top of the fruit and vegetable storage is set perpendicular to its first length direction.

6. The fruit and vegetable precooling system according to claim 5, characterized in that, The air duct includes an air duct housing. A gas flow channel is formed in the air duct housing. An installation part for connecting with the top of the fruit and vegetable storage is formed at the top of the air duct housing. Air outlet holes are formed on the peripheral side of the air duct housing. The air in the gas flow channel can flow out through the air outlet holes to the inside of the fruit and vegetable storage.

7. The fruit and vegetable precooling system according to claim 1, characterized in that, The fruit and vegetable precooling system further includes a condensing unit, and the condensing unit is placed inside the fruit and vegetable storage.

8. The fruit and vegetable precooling system according to claim 7, characterized in that, A baffle structure is arranged in the lower air return channel. The baffle structure is connected with the inner wall of the fruit and vegetable storage. The baffle structure can divide the lower air return channel into a return air channel body area and a condensing unit installation area. The lower air return opening is communicated with the return air channel body area, and the air in the return air channel body area can be sent out through the differential pressure fan.

9. The fruit and vegetable precooling system according to claim 1, characterized in that, The fruit and vegetable precooling system further includes a temperature detection structure, and the temperature detection structure is installed inside the fruit and vegetable storage.

10. A fruit and vegetable storage device, characterized in that, It includes a fruit and vegetable storage and a fruit and vegetable precooling system. Among them, the fruit and vegetable precooling system is the fruit and vegetable precooling system described in any one of claims 1 to 9, and the fruit and vegetable precooling system is arranged inside the fruit and vegetable storage.

11. A control method for a fruit and vegetable precooling system, characterized in that, For controlling the fruit and vegetable precooling system described in any one of claims 1 to 9 above, the upper air return structure includes a cold air blower, and the lower air return structure includes a differential pressure blower. The method includes: Obtaining the lowest temperature inside the fruit and vegetable storage; Comparing the lowest temperature inside the fruit and vegetable storage with the preset temperature of fruits and vegetables suitable for storage; Controlling the operation of the cold air blower and the differential pressure blower according to the comparison result; The preset temperature of fruits and vegetables includes a first preset temperature and a second preset temperature, where the first preset temperature is less than the second preset temperature; The controlling the operation of the cold air blower and the differential pressure blower according to the comparison result includes: If the lowest temperature inside the fruit and vegetable storage is greater than the second preset temperature, then control the cold air blower and the differential pressure blower to turn on; If the lowest temperature inside the fruit and vegetable storage is between the first preset temperature and the second preset temperature, then control the cold air blower to turn on, and control the operation of the differential pressure blower according to the difference between the highest temperature and the lowest temperature inside the fruit and vegetable storage.

12. The control method for a fruit and vegetable precooling system according to claim 11, characterized in that, The controlling the operation of the cold air blower and the differential pressure blower according to the comparison result further includes: If the lowest temperature inside the fruit and vegetable storage is less than the first preset temperature, then control the cold air blower, and control the operation of the differential pressure blower according to the difference between the highest temperature and the lowest temperature inside the fruit and vegetable storage.

13. The control method for a fruit and vegetable precooling system according to claim 11 or 12, characterized in that, The controlling the operation of the differential pressure blower according to the difference between the highest temperature and the lowest temperature inside the fruit and vegetable storage includes: Obtaining the highest temperature and the lowest temperature inside the fruit and vegetable storage to obtain the difference between the highest temperature and the lowest temperature; If the difference between the highest temperature and the lowest temperature inside the fruit and vegetable storage is greater than the preset difference, then control the differential pressure blower to turn on; If the difference between the highest temperature and the lowest temperature inside the fruit and vegetable storage is less than or equal to the preset difference, then control the differential pressure blower to turn off.

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