Fresh-keeping device

Abstract

A fresh-keeping device comprises a fresh-keeping chamber and a temperature adjusting assembly used for adjusting the temperature in the fresh-keeping chamber, and the temperature adjusting assembly comprises a heat exchanger located on one end side of the fresh-keeping chamber in the first direction; the cold / heat source is communicated with the heat exchanger so as to provide a secondary refrigerant for the heat exchanger; the negative pressure fan is positioned below the heat exchanger; the air duct is communicated with the negative pressure fan and the heat exchanger, and the air duct is provided with an air inlet corresponding to the negative pressure fan; and the air return cover is located on the air inlet side of the negative pressure fan, the air return cover is provided with an air return port, and the air return port is lower than the air inlet. According to the fresh-keeping device, the air return port is lower than the air inlet, so that air enters the air channel from the bottom of the fresh-keeping area, a channel corresponding to the air inlet of the negative pressure fan does not need to be reserved in the fresh-keeping area, more goods can be stored in the fresh-keeping area, and the space utilization rate is high.

Description

Technical Field

[0001] The utility model relates to the technical field of refrigeration, in particular to a fresh-keeping device. Background Art

[0002] Fresh products, from the fields, lakes and oceans to the hands of consumers, need to go through multiple links including picking / catching, pre-cooling, trunk line transportation, warehousing, sorting / distribution, etc.

[0003] In order to reduce fruit loss rate, improve freshness, extend shelf life and ensure the quality of fresh products, we advocate the use of refrigeration equipment at each stage to provide fresh products with suitable storage temperature, instead of the drugs / preservatives on the market.

[0004] Air cooling and direct cooling are two commonly used cooling methods. Air cooling mostly uses differential pressure fans / negative pressure fans to form a pressure difference on both sides of the goods, forcing low-temperature air to pass through the goods and cool them down. However, the use of differential pressure fans / negative pressure fans requires that the area corresponding to its air inlet cannot be loaded with goods, leaving air ducts, reducing the utilization rate of storage space; on the other hand, canvas needs to be laid on the goods, which is inconvenient to operate.

[0005] In view of this, it is necessary to provide an improved fresh-keeping device to solve the above technical problems. Utility Model Content

[0006] The purpose of the utility model is to provide a fresh-keeping device.

[0007] In order to solve one of the above technical problems, the utility model adopts the following technical solution:

[0008] A fresh-keeping device, comprising a fresh-keeping chamber and a temperature regulating component for regulating the temperature in the fresh-keeping chamber, wherein the temperature regulating component comprises:

[0009] A heat exchanger is located at one end of the fresh-keeping chamber in the first direction;

[0010] A cold / heat source, connected to the heat exchanger to provide a coolant thereto;

[0011] A negative pressure fan is located below the heat exchanger;

[0012] an air duct connecting the negative pressure fan and the heat exchanger, and the air duct is provided with an air inlet corresponding to the negative pressure fan;

[0013] The return air hood is located at the air inlet side of the negative pressure fan. The return air hood is provided with a return air port, and the return air port is lower than the air inlet.

[0014] Furthermore, the return air hood includes a first wind hood connected to the bottom of the fresh-keeping chamber, and a second wind hood connected to the first wind hood and the air inlet, the first wind hood is not higher than the air inlet, the second wind hood is located above the first wind hood, and the return air outlet is opened on the first wind hood.

[0015] Furthermore, the first air hood extends from one end to the other end of the fresh-keeping chamber along a second direction, the width of the second air hood is smaller than the width of the first air hood, and the second direction is perpendicular to the first direction.

[0016] Furthermore, the width of the second air cover is 1 to 1.5 times the width of the air inlet.

[0017] Furthermore, the negative pressure fan is located in the middle of the fresh-keeping chamber in the second direction, and the second air hood is connected to the middle of the first air hood.

[0018] Furthermore, the negative pressure fan includes fan blades, and the air duct around the negative pressure fan includes air duct side panels located on the circumferential side of the negative pressure fan in the horizontal direction, and the distance from the edge of the fan blade to the side panel is not less than the radius of the fan blade.

[0019] Furthermore, the heat exchanger is located at the top of the fresh-keeping room, and the temperature control component also includes an air outlet hood located downstream of the heat exchanger, and the air outlet hood is provided with an air outlet; the top plate of the air outlet hood is not lower than the top of the heat exchanger, and the bottom plate of the air outlet hood extends obliquely away from the heat exchanger and upward, and the air outlet corresponds to the upper half of the heat exchanger.

[0020] Furthermore, the preservation device also includes an air duct plate located at the top of the preservation chamber, an air outlet connected to the air outlet is formed between the air duct plate and the top wall of the preservation chamber, and the air duct plate is provided with a plurality of sub-air outlets arranged at intervals along a first direction; along the first direction, the number and / or area of ​​the sub-air outlets within a unit area close to the air outlet is not less than the number and / or area of ​​the sub-air outlets within a unit area away from the air outlet.

[0021] Furthermore, a plurality of air guide rails are provided at the bottom of the fresh-keeping device, the air guide rails extend along a first direction, and the plurality of air guide rails are spaced apart along a second direction perpendicular to the first direction.

[0022] Furthermore, the preservation device also includes a humidification component, which includes a water box, a humidifier connected to the water box, and a humidification pipe connected to the humidifier. The humidification pipe is provided with a plurality of humidification ports, and the humidification ports are located downstream of the heat exchanger.

[0023] Furthermore, the air duct also includes an air outlet hood located at the top of the fresh-keeping chamber, the air outlet hood is provided with an air outlet, and a plurality of humidification ports are arranged at intervals at the air outlet.

[0024] Furthermore, the preservation device also includes a sterilization component, which includes a sterilization module that produces sterilization components and a delivery pipe that delivers the sterilization components to the air duct, and the sterilization components include at least one of negative oxygen ions, plasma or ozone.

[0025] Further, the delivery pipeline includes a first pipeline for delivering the sterilization component to the upstream of the heat exchanger, and a second pipeline for delivering the sterilization component to the downstream of the heat exchanger; or, the delivery pipeline includes a first pipeline for delivering the sterilization component to the upstream of the heat exchanger, a second pipeline for delivering the sterilization component to the downstream of the heat exchanger, and a valve for selectively opening or closing the first pipeline and / or the second pipeline.

[0026] Furthermore, the fresh-keeping device is a refrigerator, a freezer, an insulated box, a cold storage, a freezer or an insulated storage.

[0027] The beneficial effect of the utility model is that the fresh-keeping device of the utility model allows the air to enter the air duct from the bottom of the fresh-keeping area through the return air outlet being lower than the air inlet, and there is no need to reserve a channel corresponding to the air inlet of the negative pressure fan in the fresh-keeping area. Therefore, more goods can be stored in the fresh-keeping area, and the space utilization rate is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic structural diagram of a fresh-keeping device in a preferred embodiment of the utility model;

[0029] Figure 2 for Figure 1 Schematic diagram after removing part of the box;

[0030] Figure 3 for Figure 2 A partial enlarged view of the middle A;

[0031] Figure 4 for Figure 1 A schematic diagram from another viewing angle (left side of the diagram);

[0032] Figure 5 for Figure 4 Section along BB direction;

[0033] Figure 6 for Figure 5 A schematic diagram of the temperature control component in another perspective;

[0034] Figure 7 This is a schematic diagram of the temperature control assembly of the utility model after removing the first side plate;

[0035] Figure 8 for Figure 2 A schematic diagram of the temperature control assembly shown in another perspective;

[0036] Fig. 9 for Figure 8 A partial enlarged view of point C in the middle;

[0037] Fig.10 for Figure 8 A partial enlarged view of point D in the middle;

[0038] Fig.11 for Figure 2 The schematic diagram of the temperature control assembly shown in another perspective after removing the top plate of the air outlet cover;

[0039] Fig.12 for Fig.11 A partial enlarged view of point E in the middle;

[0040] Fig.13 for Figure 2 A schematic diagram of the temperature control assembly shown in another perspective;

[0041] Fig.14 for Figure 2 A schematic diagram of the temperature control assembly shown in another perspective;

[0042] Fig.15 for Fig.14 A partial enlarged view of the F in the middle;

[0043] Fig.16 for Fig.14 A partial enlarged view of the G in the middle;

[0044] Fig.17 for Figure 2 Schematic diagram of the temperature control component and the air outlet plate.

[0045] 100-fresh-keeping device, 1-fresh-keeping chamber, 2-temperature adjustment component, 21-heat exchanger, 22-negative pressure fan, 23-air duct, 230-air inlet, 231-air duct bottom plate, 232-first side plate, 233-second side plate, 234-third side plate, 24-return air hood, 240-return air outlet, 241-first air hood, 242-second air hood, 3-air outlet hood, 30-air outlet, 4-air duct plate, 40-sub-air outlet, 5-air guide rail, 6-humidification component, 61-humidifier, 62-humidification tube, 63-humidification port, 7-sterilization component, 71-sterilization module, 72-conveying pipeline, 721-first pipeline, 722-second pipeline, 8-maintenance port. DETAILED DESCRIPTION

[0046] The present invention will be described in detail below in conjunction with the specific embodiments shown in the accompanying drawings. However, these embodiments do not limit the present invention, and any structural, methodological, or functional changes made by a person skilled in the art based on these embodiments are all within the scope of protection of the present invention.

[0047] In various drawings of the present invention, for the convenience of illustration, some dimensions of structures or parts are exaggerated relative to other structures or parts, and therefore, are only used to illustrate the basic structure of the subject matter of the present invention.

[0048] For the convenience of description, this article uses the specific usage scenario of the fresh-keeping device 100 as a reference to define the upper (top) and lower (bottom) directions; upstream and downstream are defined according to the direction of air flow, and the negative pressure fan 22 drives the air to flow from upstream to downstream.

[0049] Please refer to Figure 1 to Figure 17 As shown, the fresh-keeping device 100 of the utility model comprises a fresh-keeping chamber 1 and a temperature regulating component 2. The temperature regulating component 2 is used to provide cooling or heating to the fresh-keeping chamber 1 to maintain the temperature within the required range for fresh products.

[0050] Specifically, when the ambient temperature is higher than the fresh-keeping temperature required for fresh products, the temperature regulating component 2 provides cooling to the fresh-keeping chamber 1; when the ambient temperature is lower than the fresh-keeping temperature required for fresh products, the temperature regulating component 2 provides heat to the fresh-keeping chamber 1.

[0051] The fresh-keeping room 1 is provided with a fresh-keeping area and an equipment area, wherein the fresh-keeping area is used to store fresh products, and the equipment area is used to install equipment components such as the temperature control component 2. The equipment area is located at one end of the fresh-keeping room 1 along the first direction, preferably at one end of the fresh-keeping room 1 in the length direction.

[0052] The temperature control component 2 includes a heat exchanger 21, a cold / heat source connected to the heat exchanger 21 to provide it with a coolant, a negative pressure fan 22, an air duct 23 connecting the negative pressure fan 22 and the heat exchanger 21, and a return air hood 24 located on the air inlet side of the negative pressure fan 22.

[0053] The heat exchanger 21 is located at the top of the equipment area, and the size / heat exchange area of ​​the heat exchanger 21 is adaptively matched according to the volume of the fresh-keeping area to ensure the heat exchange amount per unit time.

[0054] The cold / heat source is a refrigeration unit or a cold storage module, which can be installed in the vacant area of ​​the equipment area outside the box; it can provide the heat exchanger 21 with a refrigerant with a temperature between -60°C and 15°C. Specifically, according to the target temperature of the fresh-keeping zone, a refrigerant with a corresponding temperature is provided to provide it with cold or heat. Generally, the temperature of the refrigerant has a temperature difference of 5°C or more from the target temperature of the fresh-keeping zone. When cooling, the temperature of the refrigerant is at least 5°C lower than the target temperature of the fresh-keeping zone; when heating is required, the temperature of the refrigerant is at least 5°C higher than the target temperature of the fresh-keeping zone.

[0055] In one embodiment, the cold / heat source is a refrigeration unit, including a compressor, a condenser, a throttling element and an evaporator. The evaporator is a plate evaporator, including a refrigerant channel and a coolant channel, and the coolant channel is connected to the heat exchanger 21 to provide a coolant with a suitable temperature.

[0056] In another embodiment, the cold / heat source is a cold storage box connected to the heat exchanger 21, and a refrigeration unit or a cold charging station provides cold or heat to the coolant in the cold storage box.

[0057] The negative pressure fan 22 is also called a pressure difference fan, and is located below the heat exchanger 21, and the negative pressure fan 22 is located upstream of the heat exchanger 21, that is, the heat exchanger 21 is located on the air outlet side of the negative pressure fan 22. Compared with setting the heat exchanger 21 on the air inlet side of the negative pressure fan 22, the heat exchanger 21 of the utility model is located on the air outlet side of the negative pressure fan 22, which reduces the pressure requirement for the negative pressure fan 22 on the one hand, and on the other hand, the return air enters the fresh-keeping area immediately after heat exchange with the heat exchanger 21, which reduces energy waste.

[0058] The air duct 23 connects the negative pressure fan 22 and the heat exchanger 21 , which can also be understood as the negative pressure fan 22 and the heat exchanger 21 are located in the air duct 23 .

[0059] The air duct 23 defines an air flow path / flow trajectory, so that the air discharged by the negative pressure fan 22 passes through the entire heat exchanger 21 to achieve heat exchange with it. Preferably, the air duct 23 guides the air to the side of the heat exchanger 21 away from the fresh-keeping area, and the air directly enters the fresh-keeping area after passing through the heat exchanger 21.

[0060] In this embodiment, the inner diameter of the air duct 23 gradually increases from bottom to top, forming an inverted funnel shape; the air from the negative pressure fan 22 diffuses along the air duct 23 to the entire heat exchanger 21 .

[0061] The negative pressure fan 22 includes a fan blade, wherein the axis thereof is arranged horizontally. The air duct 23 around the negative pressure fan 22 includes an air duct bottom plate 231 located below the negative pressure fan 22, and an air duct side plate located around the negative pressure fan 22 in the horizontal direction, wherein the air duct side plate extends upward to the heat exchanger 21, and the air inlet 230 is arranged at a position on the air duct side plate corresponding to the negative pressure fan 22, and the air in the fresh-keeping area enters the air duct 23 horizontally, and then flows upward to the heat exchanger 21.

[0062] Preferably, the distance from the edge of the fan blade to the side plate is not less than the radius of the fan blade, and after the fan exhaust reaches the side plate, it flows upward, the exhaust is smooth, and the wind resistance is small. If the distance is too small, the exhaust is limited by the side plate, causing airflow turbulence in a small space and unsmooth exhaust.

[0063] Specifically, the air duct side plate includes a first side plate 232 located on the side of the negative pressure fan 22 facing the fresh-keeping area, a second side plate 233 located on the side of the negative pressure fan 22 facing away from the fresh-keeping area, and a pair of third side plates 234 connecting the first side plate 232 and the second side plate 233. The air inlet 230 is provided at a position on the first side plate 232 corresponding to the negative pressure fan 22, and the distance from the edge of the fan blade to the third side plate 234 is not less than the radius of the fan blade.

[0064] The return air hood 24 is provided with a return air port 240, and the return air port 240 is lower than the air inlet 230. The air enters the air duct 23 from the bottom of the fresh-keeping area. There is no need to reserve a return air channel corresponding to the air inlet 230 in the fresh-keeping area. Therefore, the entire fresh-keeping area can be filled with goods, with high space utilization. The risk of goods tipping over during transportation of the fresh-keeping device 100 can also be avoided.

[0065] Specifically, the return air hood 24 includes a first wind hood 241 connected to the bottom of the fresh-keeping chamber 1, and a second wind hood 242 connected to the first wind hood 241 and the air inlet 230, the first wind hood 241 is not higher than the air inlet 230, the second wind hood 242 is located above the first wind hood 241, and the return air port 240 is opened on the first wind hood 241.

[0066] Preferably, the first wind hood 241 extends from one end to the other end along the second direction of the fresh-keeping chamber 1 to ensure effective return air in the entire width direction of the fresh-keeping area; the width of the second wind hood 242 is smaller than the width of the first wind hood 241, and the return air enters the first wind hood 241, and after mixing, enters the negative pressure fan 22 through the second wind hood 242.

[0067] Preferably, the width of the second air cover 242 is 1 to 1.5 times the width of the air inlet 230, so that the return air is concentrated and enters the negative pressure fan 22 to avoid the generation of vortices there.

[0068] In this embodiment, the negative pressure fan 22 is located in the middle of the fresh-keeping chamber 1 in the second direction, the second wind cover 242 is connected to the middle of the first wind cover 241, and the first wind cover 241 and the second wind cover 242 are in a "convex" shape as a whole.

[0069] Furthermore, the temperature control component 2 also includes an air outlet hood 3 located downstream of the heat exchanger 21, and the air outlet hood 3 is provided with an air outlet 30, and the air outlet 30 is located at the top of the fresh-keeping chamber 1, so that the cold air / hot air after passing through the heat exchanger 21 enters the top of the fresh-keeping area.

[0070] Preferably, the top plate of the air outlet hood 3 is not lower than the top of the heat exchanger 21 , and the bottom plate of the air outlet hood 3 extends obliquely away from the heat exchanger 21 and upward, so that the air outlet 30 corresponds to the upper half of the heat exchanger 21 .

[0071] Furthermore, if Fig.17 As shown, the fresh-keeping device 100 also includes an air duct plate 4, which is located at the top of the fresh-keeping chamber 1, and an air outlet 23 connected to the air outlet 30 is formed between the air duct plate 4 and the top wall of the fresh-keeping chamber 1, and a plurality of sub-air outlets 40 arranged at intervals along a first direction are provided on the air duct plate 4, and the cold air / hot air passing through the heat exchanger 21 enters the fresh-keeping area below from the sub-air outlets 40 to provide cooling for the goods.

[0072] Preferably, along the first direction, the number and / or area of ​​the sub-air outlets 40 within a unit area close to the air outlet 30 is not less than the number and / or area of ​​the sub-air outlets 40 within a unit area away from the air outlet 30. Therefore, the area of ​​all the sub-air outlets 40 within a unit area close to the air outlet 30 is not less than the area of ​​all the sub-air outlets 40 within a unit area away from the air outlet 30, so that the air outlets in different areas in the first direction are more uniform.

[0073] Furthermore, a plurality of air guide rails 5 are provided at the bottom of the fresh-keeping device 100, the air guide rails 5 extend in a first direction, and the plurality of air guide rails 5 are arranged in a second direction perpendicular to the first direction, and a return air duct 23 is formed between adjacent air guide rails 5. Goods are directly placed on the air guide rails 5, and a natural air duct 23 is formed on the top of the goods, and the cold air / hot air passing through the heat exchanger 21 flows from the top of the goods to the other end, flows downward through the goods, and returns to the return air port 240 through the return air duct 23 at the bottom.

[0074] Preferably, the air guide rail 5 is a T-shaped rail or a square rail, and the top surface is a flat surface, which is convenient for placing goods.

[0075] Of course, the air guide rail 5 may not be provided at the bottom of the fresh-keeping device 100, and the return air duct 23 is formed between the pallet and the bottom of the fresh-keeping area by loading the goods on the pallet.

[0076] Furthermore, fresh products need necessary humidity when refrigerated. The inventors have found that the current humidification components 6 directly release water vapor to the fresh-keeping area. In order to achieve a uniform humidification effect, humidification ports 63 are usually required to be arranged along the entire fresh-keeping area, which is complex in structure and high in cost.

[0077] In the utility model, a humidifying assembly 6 is installed in the equipment area, and water vapor is transported to the air duct 23. The water vapor flows into the entire fresh-keeping area along with the air flow. The layout is simple and the humidification uniformity is good.

[0078] The humidifying assembly 6 includes a water box, a humidifier 61 connected to the water box, and a humidifying pipe 62 connected to the humidifier 61. The humidifying pipe 62 is provided with a plurality of humidifying ports 63. The humidifying ports 63 are located downstream of the heat exchanger 21, so that water vapor will not condense on the surface of the heat exchanger 21.

[0079] Preferably, the humidification tube 62 extends to the air outlet hood 3, and a plurality of the humidification ports 63 are arranged at intervals at the air outlet 30, and water vapor enters the fresh-keeping area along with the air after passing through the heat exchanger 21, thereby ensuring the required temperature and humidity for fresh products.

[0080] In this embodiment, the end section of the humidification tube 62 is arranged along the circumference of the air outlet 30, and the humidification ports 63 are evenly arranged around the air outlet 30, so that water vapor is evenly mixed into the cold / hot air.

[0081] Furthermore, the inventors have found that bacteria will grow in the fresh-keeping room 1 during use, and sterilization is required. The current sterilization component 7 is directly installed in the fresh-keeping area, the sterilization range is uneven, and the air duct 23 and its internal components cannot be sterilized.

[0082] The fresh-keeping device 100 further includes a sterilization component 7, which includes a sterilization module 71 for generating sterilization components and a delivery pipe 72 for delivering the sterilization components to the air duct 23, wherein the sterilization components include at least one of negative oxygen ions, plasma or ozone.

[0083] In the present invention, the delivery pipeline 72 includes a first pipeline 721 for delivering the sterilizing component to the upstream of the heat exchanger 21, and a second pipeline 722 for delivering the sterilizing component to the downstream of the heat exchanger 21. The sterilizing component provided by the first pipeline 721 can disinfect the heat exchanger 21, and the undecomposed sterilizing component can also flow into the fresh-keeping area with the air. The sterilizing component released by the second pipeline 722 directly and evenly enters the fresh-keeping area with the air, and sterilizes and disinfects the goods in the fresh-keeping area and the goods therein.

[0084] Preferably, it also includes a valve for opening or closing the first pipeline 721 and / or the second pipeline 722. The two pipelines share one valve or each uses a separate valve. Both pipelines can be selectively opened one by one or simultaneously to sterilize the heat exchanger 21 and / or the fresh-keeping area, thereby extending the shelf life of fresh products.

[0085] Specifically, when the heat exchanger 21 needs to be sterilized, the first pipe 721 is opened; when the fresh-keeping area needs to be sterilized, the second pipe 722 is opened; when both the heat exchanger 21 and the fresh-keeping area need to be sterilized, the first pipe 721 and the second pipe 722 are opened at the same time.

[0086] In this embodiment, the sterilization component 7 and the humidification component 6 are respectively arranged on both sides of the air duct 23 along the second direction, and the space arrangement is reasonable.

[0087] In addition, the utility model preferably installs the above-mentioned equipment components through a mounting frame, and forms a maintenance channel in the space of the mounting frame, for example, a maintenance channel is formed on both sides of the air duct 23 along the second direction. The fresh-keeping device 100 also includes a maintenance port 8 connected to the equipment area, which is convenient for maintenance of the temperature control component 2, the sterilization component 7, and the humidification component 6.

[0088] The fresh-keeping device 100 of the utility model can be used as a mobile heat preservation box, refrigerator or freezer, or as a fixed heat preservation storehouse, refrigerator or freezer. It can be used for pre-cooling, removing the field heat of fresh products, quickly reducing the ambient temperature to the temperature required for refrigeration, suppressing the respiratory heat, and realizing rapid fresh lock; it can also be used for cold preservation, providing the necessary refrigeration temperature for the pre-cooled fresh products.

[0089] In summary, the fresh-keeping device 100 of the present invention, through the return air port 240 being lower than the air inlet 230, allows air to enter the air duct 23 from the bottom of the fresh-keeping area, and there is no need to reserve a channel corresponding to the air inlet 230 of the negative pressure fan 22 in the fresh-keeping area. Therefore, more goods can be stored in the fresh-keeping area, and the space utilization rate is high.

[0090] It should be understood that although this specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each implementation mode may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

[0091] The series of detailed descriptions listed above are only specific descriptions of feasible implementation methods of the utility model. They are not intended to limit the protection scope of the utility model. Any equivalent implementation methods or changes that do not deviate from the technical spirit of the utility model should be included in the protection scope of the utility model.

Claims

1. A fresh-keeping device, comprising a fresh-keeping chamber and a temperature regulating component for regulating the temperature in the fresh-keeping chamber, characterized in that: The temperature adjustment component comprises: A heat exchanger is located at one end of the fresh-keeping chamber in the first direction; A cold / heat source, connected to the heat exchanger to provide a coolant thereto; A negative pressure fan is located below the heat exchanger; an air duct connecting the negative pressure fan and the heat exchanger, and the air duct is provided with an air inlet corresponding to the negative pressure fan; The return air hood is located at the air inlet side of the negative pressure fan. The return air hood is provided with a return air port, and the return air port is lower than the air inlet.

2. The fresh-keeping device according to claim 1, characterized in that: The return air hood includes a first hood connected to the bottom of the fresh-keeping room and a second hood connected to the first hood and the air inlet. The first hood is not higher than the air inlet, the second hood is located above the first hood, and the return air outlet is opened on the first hood.

3. The fresh-keeping device according to claim 2, characterized in that: The first air cover extends from one end to the other end of the fresh-keeping chamber along a second direction, the width of the second air cover is smaller than the width of the first air cover, and the second direction is perpendicular to the first direction.

4. The fresh-keeping device according to claim 3, characterized in that: The width of the second air cover is 1 to 1.5 times the width of the air inlet.

5. The fresh-keeping device according to claim 3, characterized in that: The negative pressure fan is located in the middle of the fresh-keeping chamber in the second direction, and the second air cover is connected to the middle of the first air cover.

6. The fresh-keeping device according to claim 1, characterized in that: The negative pressure fan includes fan blades, and the air duct around the negative pressure fan includes air duct side panels located on the circumferential side of the negative pressure fan in the horizontal direction, and the distance from the edge of the fan blade to the side panel is not less than the radius of the fan blade.

7. The fresh-keeping device according to claim 1, characterized in that: The heat exchanger is located at the top of the fresh-keeping room, and the temperature control component also includes an air outlet hood located downstream of the heat exchanger, and the air outlet hood is provided with an air outlet; the top plate of the air outlet hood is not lower than the top of the heat exchanger, and the bottom plate of the air outlet hood extends obliquely away from the heat exchanger and upward, and the air outlet corresponds to the upper half of the heat exchanger.

8. The fresh-keeping device according to claim 7, characterized in that: The preservation device also includes an air duct plate located at the top of the preservation chamber, an air outlet connected to the air outlet is formed between the air duct plate and the top wall of the preservation chamber, and a plurality of sub-air outlets are arranged at intervals along a first direction are provided on the air duct plate; along the first direction, the number and / or area of ​​the sub-air outlets within a unit area close to the air outlet is not less than the number and / or area of ​​the sub-air outlets within a unit area away from the air outlet.

9. The fresh-keeping device according to any one of claims 1 to 8, characterized in that: A plurality of air guide rails are arranged at the bottom of the fresh-keeping device. The air guide rails extend along a first direction, and the plurality of air guide rails are arranged at intervals along a second direction perpendicular to the first direction.

10. The fresh-keeping device according to any one of claims 1 to 8, characterized in that: The fresh-keeping device also includes a humidifying component, which includes a water box, a humidifier connected to the water box, and a humidifying pipe connected to the humidifier. The humidifying pipe is provided with a plurality of humidifying ports, and the humidifying ports are located downstream of the heat exchanger.

11. The fresh-keeping device according to claim 10, characterized in that: The air duct also includes an air outlet cover located at the top of the fresh-keeping chamber, the air outlet cover is provided with an air outlet, and a plurality of humidification ports are arranged at intervals at the air outlet.

12. The fresh-keeping device according to any one of claims 1 to 8, characterized in that: The fresh-keeping device also includes a sterilization component, which includes a sterilization module that produces sterilization components and a delivery pipeline that delivers the sterilization components to the air duct. The sterilization components include at least one of negative oxygen ions, plasma or ozone.

13. The fresh-keeping device according to claim 12, characterized in that: The delivery pipeline includes a first pipeline for delivering the sterilizing component to the upstream of the heat exchanger and a second pipeline for delivering the sterilizing component to the downstream of the heat exchanger; Alternatively, the delivery pipeline includes a first pipeline for delivering the sterilization component to the upstream of the heat exchanger, a second pipeline for delivering the sterilization component to the downstream of the heat exchanger, and a valve for selectively opening or closing the first pipeline and / or the second pipeline.

14. The fresh-keeping device according to claim 1, characterized in that: The fresh-keeping device is a refrigerator, a freezer, an insulated box, a cold storage, a frozen storage or an insulated storage.

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