CN113446803B

CN113446803B - Controlled atmosphere preservation device, fruit and vegetable preservation method based on refrigerator, controller and refrigerator

Info

Publication number: CN113446803B
Application number: CN202010212519.1A
Authority: CN
Inventors: 周新; 任相华; 胡海宏; 王喆
Original assignee: Hefei Hualing Co Ltd; Midea Group Co Ltd; Hefei Midea Refrigerator Co Ltd
Current assignee: Hefei Hualing Co Ltd; Midea Group Co Ltd; Hefei Midea Refrigerator Co Ltd
Priority date: 2020-03-24
Filing date: 2020-03-24
Publication date: 2022-09-20
Anticipated expiration: 2040-03-24
Also published as: CN113446803A

Abstract

The invention discloses an air-conditioning preservation device, a refrigerator-based fruit and vegetable preservation method, a controller and a refrigerator. The fruit and vegetable fresh-keeping method comprises the following steps: controlling a vacuumizing device to vacuumize the accommodating space; controlling the nitrogen generating device to generate and fill nitrogen-rich gas into the accommodating space so as to enable the volume concentration of oxygen in the accommodating space to reach a preset proportion; refrigerating the fruits and vegetables in the accommodating space at a set temperature; controlling the air interchanger to start a second preset time period every other first preset time period; controlling the nitrogen generating device to generate and fill nitrogen-rich gas into the accommodating space so as to enable the volume concentration of oxygen in the accommodating space to reach a preset proportion; and refrigerating the fruits and vegetables in the accommodating space at a set temperature. The method has the following beneficial effects: through setting up breather, regularly discharge above-mentioned bad gas, can further prolong the fresh-keeping of fruit vegetables for a long time to improve fresh-keeping effect.

Description

Controlled atmosphere preservation device, fruit and vegetable preservation method based on refrigerator, controller and refrigerator

Technical Field

The invention belongs to the field of refrigeration storage, and particularly relates to a modified atmosphere preservation device, a refrigerator-based fruit and vegetable preservation method, a controller and a refrigerator.

Background

In the prior art, in order to keep fruits and vegetables fresh, a mode of reducing the volume concentration of oxygen or reducing the volume concentration of oxygen is often adopted to reduce the respiration of the fruits and vegetables and slow down the consumption speed of organic matters.

In the related art, the method of modified atmosphere preservation by reducing the volume concentration of oxygen has been used for preserving fruits and vegetables, but the preservation effect is not ideal.

The above is only for the purpose of assisting understanding of the technical aspects of the present invention, and does not represent an admission that the above is prior art.

Disclosure of Invention

The present invention is directed to solving at least one of the problems of the prior art. Therefore, the invention provides a modified atmosphere preservation device with a good preservation effect, a fruit and vegetable preservation method based on a refrigerator, a controller, the refrigerator and a computer readable storage medium.

The modified atmosphere preservation device according to the embodiment of the first aspect of the invention is arranged in a refrigerating space of a refrigerator and comprises the following components: the air-conditioning preservation box body is provided with a containing space which can be closed and an air inlet communicated with the containing space; the modified atmosphere generating device is connected with the modified atmosphere preservation box body, can vacuumize the accommodating space through the air inlet, can also generate nitrogen-rich gas, and fills the nitrogen-rich gas into the accommodating space through the air inlet; the air interchanger is arranged on the air-conditioning preservation box body and can enable the accommodating space to be communicated with or isolated from the refrigerating chamber; wherein the volume concentration of nitrogen in the nitrogen-rich gas is more than 90 vol.%.

The modified atmosphere preservation device provided by the embodiment of the invention at least has the following beneficial effects: the modified atmosphere preservation device can realize vacuum refrigeration and low-oxygen filling refrigeration of the accommodating space, and greatly prolong the preservation time of fruit and vegetable foods; simultaneously, the fruit vegetables are cold-stored in low oxygen low temperature environment in-process, still can carry out a small amount of respiration, produce harmful gas such as ethylene and ethanol, through setting up breather, regularly discharge above-mentioned harmful gas, can further prolong the fresh-keeping of fruit vegetables for a long time to improve fresh-keeping effect.

According to some embodiments of the invention, the modified atmosphere generating apparatus comprises: the shell is provided with an air outlet used for being connected with the air inlet; a vacuum pump having a pump inlet pipe and a pump outlet pipe; the adsorption cylinder is internally provided with an oxygen adsorbent and is provided with a cylinder air inlet pipe and a cylinder air outlet pipe, the cylinder air inlet pipe is simultaneously connected with the pump air inlet pipe and the pump air outlet pipe, a first three-way valve and a third three-way valve are sequentially connected between the cylinder air inlet pipe and the pump air inlet pipe, a second three-way valve is connected between the cylinder air inlet pipe and the pump air outlet pipe, the first three-way valve and the second three-way valve are both communicated with the refrigerating space, and the third three-way valve is connected with the air outlet; the nitrogen storage tank is provided with a tank air inlet pipe and a tank air outlet pipe, the tank air inlet pipe is communicated with the cylinder air outlet pipe, and the tank air outlet pipe is communicated with the air outlet.

According to some embodiments of the invention, the modified atmosphere preservation box further comprises: the lower-layer frame is provided with an accommodating space, an opening communicated with the accommodating space and an air inlet; the upper layer frame is provided with a refrigeration air channel, and the refrigeration air channel is used for refrigerating the accommodating space; and the drawer can enter and be contained in the containing space through the opening so as to form a closed containing space by matching with the modified atmosphere preservation box body.

According to the fruit and vegetable fresh-keeping method based on the refrigerator in the embodiment of the second aspect of the invention, the fresh-keeping box body is arranged in the refrigerating chamber of the refrigerator, and the fresh-keeping box body is provided with a closed accommodating space for accommodating fruits and vegetables; the vacuumizing device and the nitrogen generating device are connected with the preservation box body; the air interchanger is arranged on the fresh-keeping box body and can open or close the communication between the accommodating space and the cold storage chamber;

the fruit and vegetable preservation method comprises the following steps:

controlling the vacuumizing device to vacuumize the accommodating space;

controlling the nitrogen generating device to generate and fill nitrogen-rich gas into the accommodating space so that the volume concentration of oxygen in the accommodating space reaches a preset proportion, wherein the volume concentration of nitrogen in the nitrogen-rich gas is more than 90v ol.%;

refrigerating the fruits and vegetables in the accommodating space at a set temperature;

controlling the ventilation device to be started for a second preset time period every other first preset time period;

controlling the nitrogen generating device to generate and fill nitrogen-rich gas into the accommodating space so that the volume concentration of oxygen in the accommodating space reaches the preset proportion;

and refrigerating the fruits and vegetables in the accommodating space at the set temperature.

The fruit and vegetable fresh-keeping method based on the refrigerator provided by the embodiment of the invention at least has the following beneficial effects: firstly, vacuum precooling is carried out, so that the environmental heat of the accommodating space and the respiration heat of the fruits and vegetables can be quickly eliminated, and the respiration of the fruits and vegetables can be reduced as soon as possible; filling nitrogen into the accommodating space to enable the volume concentration of the nitrogen and the oxygen in the accommodating space to reach a preset ratio, so that the fruits and vegetables are in an optimal fresh-keeping storage environment; by the closed design of the accommodating space, the high humidity of the preservation box can be maintained, and the dynamic maintaining time of the preservation optimal gas component interval can be prolonged; in addition, the fruits and vegetables can also perform a small amount of respiration in the low-oxygen low-temperature environment refrigeration process to generate ethylene, ethanol and other harmful gases, and the harmful gases are regularly discharged through the arrangement of the ventilation device, so that the fresh-keeping time of the fruits and vegetables can be further prolonged, and the fresh-keeping effect is improved.

According to some embodiments of the invention, the set temperature is: -1 ℃ to 4 ℃.

According to some embodiments of the invention, the preset ratio is: the oxygen volume concentration is 1 vol.% to 15 vol.%.

According to some embodiments of the present invention, an oxygen sensor is disposed in the accommodating space, and the filling of the accommodating space with the nitrogen-rich gas to make the volume concentration of the oxygen in the accommodating space reach a preset ratio includes:

and acquiring the volume concentration of the oxygen in the accommodating space, and controlling the nitrogen generating device to be closed when the volume concentration of the oxygen reaches a preset proportion.

According to some embodiments of the invention, the charging the accommodating space with nitrogen-rich gas to make the volume concentration of oxygen in the accommodating space reach a preset ratio includes:

and controlling the time length for filling the nitrogen-rich gas into the accommodating space to a third preset time length so as to enable the volume concentration of the oxygen in the accommodating space to reach a preset proportion and control the nitrogen generating device to be closed.

A controller of a refrigerator according to an embodiment of a third aspect of the present invention includes: the fruit and vegetable fresh-keeping method comprises a memory, a processor and a computer program which is stored on the memory and can run on the processor, wherein the processor executes the program to realize the fruit and vegetable fresh-keeping method in any embodiment of the second aspect.

A refrigerator according to an embodiment of the fourth aspect of the present invention comprises a controller of the refrigerator according to any one of the embodiments of the third aspect of the present invention.

According to the computer-readable storage medium of the fifth aspect of the present invention, computer-executable instructions are stored, and the computer-executable instructions are used for executing the fresh-keeping method for fruits and vegetables described in any one of the embodiments of the second aspect.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a schematic perspective exploded view of an air-conditioned preservation device according to an embodiment of the invention;

FIG. 2 is a left side view of the controlled atmosphere preservation apparatus according to the embodiment of the invention;

FIG. 3 is a sectional view A-A of the modified atmosphere preservation apparatus of the embodiment of the invention shown in FIG. 2;

FIG. 4 is a schematic diagram of the internal structure of the controlled atmosphere generating device of the controlled atmosphere preservation device according to the embodiment of the invention;

FIG. 5 is a top view of a modified atmosphere generating device of the modified atmosphere preservation device according to the embodiment of the invention;

FIG. 6 is a schematic diagram of the vacuum pumping process of the controlled atmosphere generating device of the controlled atmosphere preservation device according to the embodiment of the invention;

FIG. 7 is a schematic diagram of a nitrogen generation process of the modified atmosphere generator of the modified atmosphere preservation device according to the embodiment of the invention;

FIG. 8 is a schematic diagram of an analysis process of the controlled atmosphere generating device of the controlled atmosphere preservation device according to the embodiment of the invention;

fig. 9 is a schematic perspective view of a refrigerator according to an embodiment of the present invention;

FIG. 10 is a method diagram of the method for keeping fruits and vegetables fresh according to the first embodiment of the present invention;

FIG. 11 is a method diagram of a method for keeping fruits and vegetables fresh according to a second embodiment of the present invention;

FIG. 12 is a method diagram of a method for keeping fruits and vegetables fresh according to a third embodiment of the present invention;

FIG. 13 is a system architecture diagram of a controller in accordance with an embodiment of the present invention;

fig. 14 is a system configuration diagram of a refrigerator according to an embodiment of the present invention.

Reference numerals: a controlled atmosphere preservation device 100; a modified atmosphere preservation box body 101; an upper frame 102; a lower frame 103; a drawer 104; a modified atmosphere generating device 105; an air outlet 106; a housing 107; a sealing strip 108; an end cap 109; a guide rail 110; an opening 111; an accommodating space 112;

a cold air inlet 201;

a refrigeration air duct 301; an adsorption cartridge 302; a nitrogen storage tank 303; a flow of cold air 304; nitrogen stream 305; a cold air outlet 306; a recess 307; a housing space 308; a damper 309; a drive device 310; an intake port 311;

a vacuum pump 401; a pump intake pipe 402; a first three-way valve 403; a second three-way valve 404; a barrel intake duct 405; a pump-out gas pipe 406; a tank intake pipe 407; a tank outlet duct 408; a barrel outlet pipe 409; a first check valve 410; a second check valve 411; a third three-way valve 412;

a refrigerator 900; a refrigerating compartment 901;

a controller 1300; a processor 1301; a memory 1302; and a bus 1303.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.

Furthermore, the terms "first," "second," and "third," etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first" and "second" may explicitly or implicitly include one or more features.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the term "connected" is to be interpreted broadly, and may be, for example, a fixed connection or a movable connection, a detachable connection or a non-detachable connection, or an integral connection; may be mechanically connected, may be electrically connected or may be in communication with each other; they may be directly connected or indirectly connected through intervening media, or may be connected through one or more other elements or indirectly connected through one or more other elements or in an interactive relationship between two elements.

In the description of the present invention, it should be noted that the technical names of the various elements in the refrigerator 900 and the modified atmosphere preservation apparatus 100 of the present invention should be understood to be broad for those skilled in the art, and the application range of the technical idea should not be limited.

The following disclosure provides many different embodiments, or examples, for implementing different aspects of the invention.

Referring to fig. 1 to 5, the modified atmosphere preservation apparatus 100 according to the first aspect of the present invention is used in a refrigerator 900 and is disposed in a refrigerating compartment 901 (see fig. 9) of the refrigerator 900, and the refrigerator 900 may refer to a broad refrigeration storage device, such as a refrigerator, an electric freezer, and a refrigerated cabinet.

In some embodiments, referring to fig. 1-3, a modified atmosphere preservation apparatus 100 comprises: the modified atmosphere preservation box body 101 is provided with a containing space 308 which can be closed, and an air inlet 311 communicated with the containing space 308; the modified atmosphere generating device 105 is connected to the modified atmosphere preservation box body 101, the modified atmosphere generating device 105 can vacuumize the accommodating space 308 through the air inlet 311, can also generate nitrogen-rich gas, and can charge the nitrogen-rich gas into the accommodating space 308 through the air inlet 311; the air interchanger is arranged on the air-conditioning preservation box body 101 and can enable the accommodating space 308 to be communicated with or isolated from the refrigerating compartment 901; wherein the volume concentration of nitrogen in the nitrogen-rich gas is more than 90 vol.%.

In the above embodiment, the modified atmosphere generator 105 uses the PSA nitrogen production method to remove oxygen from air (in the present embodiment, cold air in the refrigerator 900) to generate nitrogen-rich gas (i.e., high-concentration nitrogen gas), and injects the high-concentration nitrogen gas into the storage space 308 to keep food such as fruits and vegetables fresh. Pressure Swing adsorption (psa) is a mainstream technology for producing gas at present, and specifically, pressure Swing adsorption refers to pressurizing mixed gas, adsorbing redundant impurity gas by using an adsorbent to obtain relatively pure single gas, and desorbing the impurity gas in the adsorbent by using a method of reducing pressure or normal pressure to perform secondary utilization on the adsorbent. The oxygen adsorbent is a common adsorbent for extracting high-concentration nitrogen from air by realizing oxygen-nitrogen separation at present, and the adsorption amount of the oxygen adsorbent to oxygen is greatly higher than that of nitrogen when the adsorption pressure is the same. The PSA nitrogen production method utilizes the principle, takes air as raw material, applies pressure swing adsorption technology, and utilizes selective adsorption of oxygen and nitrogen by oxygen adsorbent to realize separation of nitrogen and oxygen in the air, thereby producing high-concentration nitrogen. In the above embodiment, the volume concentration of the nitrogen in the nitrogen-rich gas is 90 vol.% or more, for example, 90 vol.%, 93 vol.%, 97 vol.%, and 99 vol.%, taking into account the volume and usage requirements of the modified atmosphere generator 105.

It should be noted that the purpose of the controlled atmosphere generating device 100 is to vacuumize the accommodating space 308 and not to make the accommodating space 308 reach a high vacuum degree, so that the accommodating space 308 generates a certain negative pressure and the accommodating space 308 is not completely sealed, and when the accommodating space 308 reaches a certain negative pressure, the cold air in the refrigerating compartment 901 will be sucked into the accommodating space 308 through the joint of the opening part of the controlled atmosphere preservation box body 101. In some embodiments, the vacuum level that can be achieved by the receiving space 308 is 0.09 Mpa.

It should also be noted that, in order to communicate or isolate the accommodating space 308 with the refrigerating compartment 901, the air exchange device may select an electrically controlled one-way valve or a mechanically controlled device, for example, in some embodiments, as shown in fig. 3, the mechanically controlled device may select the damper 310 driven by the driving device 310, and the damper 310 may controllably open or close the communication between the accommodating space 308 and the refrigerating compartment 901.

The modified atmosphere preservation device 100 according to the embodiment of the invention has at least the following beneficial effects: after the fruits and vegetables are placed in the accommodating space 308, a part of environmental heat and the respiratory heat of the fruits and vegetables are brought in, and the temperature of the accommodating space 308 can be rapidly reduced through the vacuumizing action of the air-conditioning generating device 105; meanwhile, by vacuumizing, harmful gases such as ethylene and ethanol carried by fruits and vegetables can be removed, and a relatively pure initial fresh-keeping environment is provided; therefore, the controlled atmosphere generating device 105 can realize vacuum refrigeration and low-oxygen refrigeration of the accommodating space 308, greatly prolong the fresh-keeping time of fruit and vegetable foods and improve the fresh-keeping effect; simultaneously, the fruit vegetables are cold-stored in low oxygen low temperature environment in-process, still can carry out a small amount of respiration, produce harmful gas such as ethylene and ethanol, through setting up breather, regularly discharge above-mentioned harmful gas, can further prolong the fresh-keeping of fruit vegetables for a long time to improve fresh-keeping effect.

In addition, as will be appreciated by those skilled in the art, the controlled atmosphere preservation apparatus 100 is electrically connected to a power source when in use in order to provide power to the controlled atmosphere preservation apparatus 100, and the controlled atmosphere preservation apparatus 100 is provided with a controller or is connected to an external controller in order to control the controlled atmosphere preservation apparatus 100.

In addition, the volume of the controlled atmosphere preservation device 100 can be greatly reduced by arranging the controlled atmosphere preservation box body 101 and the controlled atmosphere generation device 105 into an integral structure, and the controlled atmosphere preservation device 100 can be used as a modular structure and arranged in the refrigerator 900 to be used, so that the controlled atmosphere preservation device 100 is more flexible to apply.

In some embodiments, the modified atmosphere preservation apparatus 100 further comprises a check valve (not shown) disposed on the modified atmosphere box 101 to allow the gas in the receiving space 308 to be discharged out of the modified atmosphere preservation apparatus 100.

Through setting up the check valve, its aim at: after the nitrogen generated by the modified atmosphere generating device 105 enters the accommodating space 308, the gas in the accommodating space 308 is discharged out of the accommodating space 308 through the one-way valve with the increase of the pressure, and meanwhile, the outside air is prevented from entering the accommodating space 308 through the one-way valve, so that the nitrogen concentration in the accommodating space 308 is increased, and the volume concentration of the oxygen is reduced, thereby providing a low-oxygen environment.

In some embodiments, the modified atmosphere generating device 105 comprises: a housing 107 provided with an air outlet 106 for connection with an air inlet 311; a vacuum pump 401 having a pump inlet pipe 402 and a pump outlet pipe 406; the adsorption cylinder 302 is internally provided with an oxygen adsorbent, the adsorption cylinder 302 is provided with a cylinder air inlet pipe 405 and a cylinder air outlet pipe 409, the cylinder air inlet pipe 405 is simultaneously connected with a pump air inlet pipe 402 and a pump air outlet pipe 406, a first three-way valve 403 and a third three-way valve 412 are sequentially connected between the cylinder air inlet pipe 405 and the pump air inlet pipe 402, a second three-way valve 404 is connected between the cylinder air inlet pipe 405 and the pump air outlet pipe 406, and the first three-way valve 403 and the second three-way valve 404 are both communicated with the refrigerating space 901; the third three-way valve 412 is simultaneously connected with the gas outlet 106; the nitrogen storage tank 303 is provided with a tank inlet pipe 407 and a tank outlet pipe 408, the tank inlet pipe 407 is communicated with the cylinder outlet pipe 409, and the tank outlet pipe 408 is communicated with the gas outlet 106. It should be noted that the first three-way valve 403, the second three-way valve 404, and the third three-way valve 412 are all electrically controlled three-way valves, and the first three-way valve 403, the second three-way valve 404, and the third three-way valve 412 are all controlled by the controller. It should be noted that the oxygen adsorbent may be selected from carbon molecular sieves, zeolites, and the like.

During the evacuation process, the vacuum pump 401 is controllably evacuated from the accommodation space 308 at a certain negative pressure by the third three-way valve 412, and is discharged into the refrigerating compartment 901.

During the adsorption process, the vacuum pump 401 is controlled to inject air with a certain positive pressure into the adsorption cylinder 302, and the oxygen adsorbent adsorbs oxygen in the injected air. Prepared nitrogen enters the nitrogen storage tank 303 from the air outlet 106 of the adsorption cylinder 302, and a tank air outlet pipe 408 of the nitrogen storage tank 303 is communicated with the accommodating space 308 to provide the nitrogen for the accommodating space; during desorption, the vacuum pump 401 is controlled to pump air from the adsorption cylinder 302 at a negative pressure, so that oxygen can be more easily desorbed from the oxygen adsorbent and discharged.

The traditional PSA nitrogen making device is mostly used for making nitrogen on a large scale and comprises an air tank and an oil-water separation device, the working pressure of an air compressor is large, the volume is large, the structure is complex, and the requirement of making nitrogen for the refrigerator 900 cannot be met. The controlled atmosphere preservation device 100 of the embodiment of the invention adopts negative pressure desorption, reduces the pressure requirement on the vacuum pump 401, can reduce the volume of the vacuum pump 401, reduce the cost and reduce the noise, thereby being easier to be embedded into the refrigerator 900 and improving the preservation performance of the refrigerator 900. The negative pressure desorption makes the impurity gas (such as water vapor) easier to desorb and discharge, and reduces the requirement on air cleanliness. Meanwhile, the pressure generated by the vacuum pump 401 is about 0.5bar to 1bar, and the pressure is enough to extrude the air in the accommodating space 308 to be discharged through the joint part or the one-way valve of the fresh-keeping box body 101. Moreover, the arrangement of the first three-way valve 403 and the second three-way valve 404 also enables the same vacuum pump 401 to provide an air pressure function for adsorption and an air pressure function for analysis, and further reduces the overall structural volume of the modified atmosphere preservation device 100, so that the modified atmosphere preservation device 100 can be conveniently embedded into the refrigerator 900.

To more clearly illustrate the operation of the modified atmosphere generating device 105, reference is now made to fig. 6, 7, and 8. Those skilled in the art will appreciate that the following process is necessarily implemented by a controller (not shown), which may be located on the modified atmosphere generating device 105 or separate from other equipment, such as the refrigerator 900.

Figure 6 shows the evacuation of the modified atmosphere generating device 105, with the direction of the arrows showing the gas flow direction. When receiving a command for starting the adsorption process, the vacuum pump 401 operates, air is pumped out from the accommodating space 308, enters from the upper opening of the third three-way valve 412, exits from the lower opening, and is closed at the right opening, then passes through the pump air inlet pipe 402 and the pump air outlet pipe 406 in sequence, enters from the lower opening of the second three-way valve 404, exits from the left opening, and is closed at the right opening, and the vacuum pumping process is completed.

Figure 7 shows the oxygen adsorption process of the modified atmosphere generating device 105 with the direction of the arrows showing the gas flow direction. When receiving a command for starting the adsorption process, the vacuum pump 401 is operated, and air enters from the left port, exits from the lower port and is closed at the right port of the first three-way valve 403, and then passes through the third three-way valve 412, enters from the right port, exits from the lower port and is closed at the upper port; air passes through the pump air inlet pipe 402 and the pump air outlet pipe 406 in sequence, enters from the lower port, exits from the right port and is sealed at the left port of the second three-way valve 404, and enters the adsorption cylinder 302 through the cylinder air inlet pipe 405 at a certain pressure to complete the oxygen adsorption process.

Fig. 8 shows the analysis of the modified atmosphere generator 105, with the gas flow direction indicated by the arrows. When a command for starting the analysis process is received, the vacuum pump 401 is operated, air is pumped out from the adsorption cylinder 302, enters from the right port, exits from the lower port and is sealed at the left port of the first three-way valve 403, and then passes through the third three-way valve 412, enters from the right port, exits from the lower port and is sealed at the upper port; air passes through the pump air inlet pipe 402 and the pump air outlet pipe 406 in sequence, enters from the lower port of the second three-way valve 404, exits from the left port, and is sealed at the right port, so that the oxygen analysis process is completed.

It is further noted that the sorbent cartridge 302 can be made of a low cost molded plastic to reduce the weight of the modified atmosphere generating device 105 and to reduce the manufacturing cost of the modified atmosphere generating device 105. In order to enable both the right port of the first three-way valve 403 and the right port of the second three-way valve 404 to be connected to the canister intake pipe 405 of the adsorption canister 302, a three-way valve may be provided between the right port of the first three-way valve 403, the right port of the second three-way valve 404, and the canister intake pipe 405.

In some embodiments, referring to fig. 4, a first one-way valve 410 is disposed between the canister outlet conduit 409 and the canister inlet conduit 407, and a second one-way valve 411 is disposed between the outlet 106 and the canister outlet conduit 408. The first check valve 410 can prevent the nitrogen in the nitrogen storage tank 303 from flowing back to the adsorption cylinder 302, especially during the desorption process, the vacuum pump 401 can provide a negative pressure to the adsorption cylinder 302, and the first check valve 410 can prevent the nitrogen in the nitrogen storage tank 303 from flowing back. The second check valve 411 also prevents the gas in the housing space 308 from flowing back to the nitrogen storage tank 303, and the second check valve 411 also serves to maintain the low oxygen environment of the housing space 308 due to the relatively sealed design of the housing space 308.

In some embodiments, the modified atmosphere preservation box 101 comprises an upper layer frame 102 and a lower layer frame 103, the lower layer frame 103 is provided with an accommodating space 112, one side of the lower layer frame 103 is provided with an opening 111 communicated with the accommodating space 112, the other side opposite to the opening 111 is provided with an air inlet 311 communicated with the accommodating space 112, and the upper layer frame 102 is provided with a refrigerating air duct 301 for refrigerating the accommodating space 112; the drawer 104 can enter and be contained in the containing space 112 through the opening 111 to form a closed containing space 308 in cooperation with the modified atmosphere box body 101. The air inlet 311 may be disposed on another side, and is specifically determined according to the structure of the refrigerating compartment 901 of the refrigerator 900.

In the above embodiment, it can be understood that, in order to ensure that the drawer 104 and the modified atmosphere box 101 cooperate to form the closed receiving space 308, the lower frame 103 itself should be constructed in a closed structure except for the opening 111 and the air inlet 311, and the cooling air duct 301 of the upper frame 102 should be isolated from the receiving space 112 of the lower frame 103.

It should be noted that, referring to fig. 3, cold air enters the cooling air duct 301 from the cold air inlet 201 and is then discharged from the cold air outlet 306 to form a cold air flow 304, so that the cooling air duct 301 exchanges heat with the accommodating space 112 to reduce the temperature of the accommodating space 112. The nitrogen gas generated by the modified atmosphere generator 105 enters the housing space 308 through the inlet 311, thereby forming a nitrogen gas stream 305. As is known in the art, in order to transfer the low temperature of the cooling air duct 301 to the accommodating space 112 as soon as possible, the insulating member between the upper frame 102 and the lower frame 103 is made of a material with good heat transfer efficiency, such as metal.

In the above embodiments, the modified atmosphere preservation device 100 may be integrally placed in a certain low temperature environment as required, or the cooling air duct 301 of the modified atmosphere preservation device 100 may be directly connected to the air duct of the existing refrigeration equipment, so as to realize the rapid refrigeration of the accommodating space 112.

In the above embodiment, in order to ensure that the drawer 104 can conveniently enter the accommodating space 112 and accurately close the accommodating space 112 to form the closed accommodating space 308, the lower frame 103 is provided with the guide rail 110 therein, and those skilled in the art can know that the bottom of the drawer 104 is also provided with a guide mechanism (not shown in the drawings) for the guide rail 110 to cooperate with.

In the above embodiment: the drawer 104 type structure is adopted, so that the opening and the sealing are convenient; after the drawer 104 and the safety box body 101 are matched to form the closed containing space 308, the nitrogen generated by the air-conditioning generating device 105 can be ensured to be rapidly filled into the containing space 308, the oxygen-enriched gas in the containing space 308 is extruded out of the containing space 308 along with the increase of the pressure, and due to the gas diffusion principle, the gas is naturally diffused from a high-concentration place to a low-concentration place, so that the nitrogen concentration in the drawer 104 can be quickly increased to a set value (namely, the volume concentration of the oxygen can be relatively reduced to the set value), and the concentration is kept uniform; the refrigerating air duct 301 arranged on the modified atmosphere preservation box body 101 can improve the refrigerating effect of the accommodating space 308, and the good oxygen reduction effect and refrigerating capability can improve the preservation effect of foods (namely vegetables, fruits and the like); the controlled atmosphere generating device 105 can realize vacuum refrigeration and low-oxygen refrigeration of the accommodating space 308, greatly prolong the preservation time of fruit and vegetable foods and improve the preservation effect.

In some embodiments, referring to fig. 1, a sealing strip 108 is disposed between the opening 111 of the modified atmosphere box 101 and the drawer 104 to ensure the sealing property between the opening 111 and the drawer 104. It should be noted that, according to the overall structure of the modified atmosphere preservation box 101, the sealing strip 108 is arranged on the lower layer frame 103, the outline shape of the inner side of the end cover 109 of the drawer 104 is adapted to the shape of the sealing strip 108, and the sealing strip 108 can be modified polyvinyl chloride (PVC), vulcanized Ethylene Propylene Diene Monomer (EPDM) and thermoplastic ethylene propylene diene monomer (EPDM/PP) rubber strips; the sealing strip 108 can also be arranged on the inner side of the end cover 109 of the drawer 104, so that the opening 111 of the modified atmosphere preservation box body 101 and the drawer 104 can be conveniently sealed. It can be understood that when no one-way valve is arranged on the lower frame 103 or the drawer 104, the pressure value is increased to a certain value after the nitrogen generated by the modified atmosphere generating device 105 is filled into the accommodating space 308, and the gas in the accommodating space 308 can be extruded out from the sealing strip 108. The pressure value is about 0.5 bar-1 bar.

In some embodiments, referring to fig. 3, the cold air inlet 201 is formed on one side wall of the upper frame 102 on the same side as the air inlet 311 of the modified atmosphere box 101, and the cold air outlet 306 is formed on the opposite side wall (and the side of the opening 111 of the modified atmosphere box 101). The cold air inlet 201 and the cold air outlet 306 are arranged along the moving direction of the drawer 104, so that the maximum range of the refrigeration air duct 301 coincides with the maximum range of the accommodating space 112, and the refrigeration effect of the refrigeration air duct 301 on the accommodating space 112 is improved.

In some embodiments, referring to FIG. 3, the upper frame 102 is positioned to protrude from the lower frame 103 such that the modified atmosphere box 101 is positioned to form a recess 307 on one side of the opening 111, and the end 109 of at least a portion of the drawer 104 is positioned within the recess 307. So set up, on the one hand can increase the refrigeration scope in refrigeration wind channel 301, on the other hand can avoid the end cover 109 of drawer 104 to convexly locate on the modified atmosphere preservation box body 101, influence whole pleasing to the eye.

It should be noted that, the cold air outlet 306 is located on the upper frame 102 and at a position adjacent to the end cover 109 of the drawer 104, and after the drawer 104 is closed, a gap is formed between the end cover 109 of the drawer 104 and the upper frame 102, so as to prevent the end cover 109 of the drawer 104 from shielding the cold air outlet 306 of the cooling air duct 301, thereby affecting the flowability of the cold air in the cooling air duct 301.

In some embodiments, in order to detect the volume concentration of oxygen in the accommodating space 308, an oxygen volume concentration detection device (not shown in the drawings) is further disposed on the lower frame 103 or inside the drawer 104, and the nitrogen generation start time and the nitrogen generation duration of the modified atmosphere generation device 105 are controlled by obtaining a detection value of the oxygen volume concentration detection device, so as to control the volume concentration of oxygen more intelligently, improve the control accuracy, and prolong the fresh-keeping time of fruits and vegetables.

Referring to fig. 10 to 12, in order to illustrate the method for preserving fruits and vegetables based on a refrigerator according to the second aspect of the present invention, it should be noted that the following description is only exemplary and not a specific limitation of the invention.

The fruit and vegetable preservation method based on the refrigerator according to some embodiments of the present invention may be executed by a controller according to some embodiments of the present invention, and as shown in fig. 10, as a first embodiment of the fruit and vegetable preservation method according to the present invention, the refrigerator includes: a fresh-keeping box body (not shown in the figure) arranged in a refrigerating chamber of the refrigerator, wherein the fresh-keeping box body is provided with a closed accommodating space 308 for accommodating fruits and vegetables; the fresh-keeping box body is connected with a vacuumizing device (not shown in the figure) and a nitrogen generating device (not shown in the figure), and the fruit and vegetable fresh-keeping method comprises the following steps:

step S1010: controlling a vacuumizing device to vacuumize the accommodating space;

it should be noted that, the vacuum-pumping device and the nitrogen gas generating device are connected to the fresh-keeping box body, and the vacuum-pumping device and the nitrogen gas generating device can be respectively connected to the fresh-keeping box body to vacuum or fill the accommodating space with nitrogen gas, or the vacuum-pumping device and the nitrogen gas generating device can be integrated together for use, when the vacuum-pumping device and the nitrogen gas generating device are integrated together for use, the embodiment of the first aspect of the present invention can be implemented, that is, the modified atmosphere fresh-keeping device 100 disclosed in the embodiment of the first aspect of the present invention is adopted, and the structure of the modified atmosphere fresh-keeping device 100 is not described herein again.

It should be noted that the purpose of the nitrogen gas generating device is to vacuumize the accommodating space 308 and not to make the accommodating space 308 reach a high vacuum degree, so that the accommodating space 308 generates a certain negative pressure, and the sealing degree of the accommodating space 308 is general, and when the accommodating space 308 reaches a certain negative pressure, the cold air in the refrigerating compartment 901 will be sucked into the accommodating space 308 through the connection between the drawer 104 and the lower frame 103. In some embodiments, the vacuum of the receiving space 308 is 0.09 Mpa.

When the fruits and vegetables are put into the accommodating space 308, a part of environmental heat and the respiratory heat of the fruits and vegetables are brought in, after the drawer 104 is closed, the accommodating space 308 is vacuumized, the environmental heat and the respiratory heat can be rapidly eliminated, particularly, the fruits and vegetables carry ethylene, ethanol and other harmful gases, and a relatively pure initial fresh-keeping environment is provided.

In some embodiments, a duration of evacuation may be predetermined, such as 20 minutes to 60 minutes. The selection of the parameter is set in consideration of the size and noise of the vacuum pump, and in order to place the vacuum pump in the refrigerating compartment 901 of the refrigerator 900 and control the noise, the vacuum pump with a small volume and power is used, and in this case, the time for vacuuming needs to be extended to allow the air exchange of the accommodating space 308 to be more sufficient and the cooling rate of the accommodating space 308 to be increased.

Step 1020: controlling the nitrogen generating device 100 to generate and fill nitrogen-rich gas into the accommodating space 308 so that the volume concentration of oxygen in the accommodating space 308 reaches a preset proportion;

the accommodating space 308 is filled with nitrogen-rich gas, so that the volume concentration of oxygen in the accommodating space 308 is reduced, the respiration of fruits and vegetables is slowed down, the insurance time of the fruits and vegetables is prolonged, and the volume concentration of nitrogen in the nitrogen-rich gas is more than 90v ol.%.

In some embodiments, the volume concentration of oxygen is: 1 vol.% to 15 vol.%. Here, it should be noted that the volume concentration of oxygen in the accommodating space 308 is: 1 vol.% to 15 vol.%, and correspondingly, the volume concentration of the nitrogen is as follows: 99 vol.% to 85 vol.%. It should be noted that: the oxygen concentration is not as low as possible.

Taking strawberries as an example, the strawberries are refrigerated and stored in the atmosphere of a modified atmosphere crisper with the oxygen volume concentration of 1 vol.%, 3 vol.%, 10 vol.% and 15 vol.%, respectively, and the strawberries are refrigerated and stored in the atmosphere of a common air environment with the oxygen volume concentration of 21% in a comparative example, and the refrigeration temperature is the same. And evaluating the four indexes of organic matter consumption, weight loss rate, hardness change, strawberry microbial colony total number and the like respectively. Can be intuitively seen that:

referring to table 1 below, the respiration intensity of strawberry was significantly suppressed under the storage conditions of 1 vol.% O2, 3 vol.% O2, 10 vol.% O2 and 15 vol.% O2, compared to 21 vol.% O2 environment, thereby reducing the consumption of organic substances of strawberry and maintaining the excellent flavor and aroma of fruits and vegetables.

TABLE 1

Referring to the following table 2, compared with the environment of 21% O2, the strawberry weight loss rate under the storage conditions of 1% O2, 3% O2, 10% O2 and 15% O2 is small, which indicates that the controlled atmosphere preservation device 100 can effectively retain the water content of the stored strawberry;

TABLE 2

Referring to the following table 3, compared with the environment of 21 vol.% O2, the hardness of the strawberries decreases slowly under the storage conditions of 1 vol.% O2, 3 vol.% O2, 10 vol.% O2 and 15 vol.% O2, which indicates that the modified atmosphere preservation device 100 can effectively maintain the quality of the stored strawberries and prolong the storage shelf life;

TABLE 3

Referring to the following table 4, the total number of microbial colonies of strawberries under the storage conditions of 1 vol.% O2, 3 vol.% O2, 10 vol.% O2 and 15% O2 is smaller than that under the storage conditions of 21 vol.% O2 environment, which indicates that the controlled atmosphere preservation apparatus 100 can inhibit the growth of microorganisms in the stored strawberries by adjusting the gas components, thereby prolonging the storage shelf life of the strawberries.

TABLE 4

Step S1030: the fruits and vegetables in the accommodating space 308 are refrigerated at a set temperature.

In some embodiments, the set temperature is: -1 ℃ to 4 ℃. This set temperature is the normal set temperature of the refrigeration compartment 901 of the refrigerator 900. With this arrangement, on the one hand, the temperature is a more suitable storage temperature for fruits and vegetables, and on the other hand, the temperature of the refrigerating compartment 901 of the refrigerator 900 can be shared by the storage space 308.

Because the accommodating space 308 is designed to be closed, the high humidity of the preservation box can be maintained, and the RH can be maintained at about 85% -95% through tests, so that the respiration of fruits and vegetables can be further reduced in the humidity environment, and the preservation time of the fruits and vegetables can be prolonged.

Step S1040: controlling the air interchanger to start a second preset time period every other first preset time period;

the refrigerator 900 includes a ventilation device, which may be embodied as: a damper 309 and a drive 310 capable of driving the damper open.

The fruit vegetables are in the cold-stored in-process of hypoxemia low temperature environment, still can carry out a small amount of respiration, produce bad gas such as ethylene and ethanol, if the indefinite discharge can influence the fresh-keeping of fruit vegetables for a long time, the time is of a specified duration, when the fruit vegetables are taken to needs, opens accommodating space, the bad smell can appear, and is unfavorable to user's health. By opening the ventilation means, such as damper 309, for a certain period of time, the accumulation of undesirable gases such as ethylene and ethanol can be released.

In some embodiments, the first predetermined period of time is 20 hours to 30 hours and the second predetermined period of time is 2 minutes to 5 minutes. The selection of the first preset duration is mainly determined according to the volume of the accommodating space 308, and when the volume is large, the preset duration may be longer, and when the volume is small, the preset duration is shorter. The second preset time is selected in consideration of the fact that the air in the accommodating space 308 needs to be fully exchanged with the refrigerating chamber 901 on one hand, and in consideration of the fact that fruits and vegetables cannot be exposed in the air for too long, otherwise, the preservation effect is affected.

Step 1050: controlling the nitrogen generating device to generate and fill nitrogen-rich gas into the accommodating space so as to enable the volume concentration of oxygen in the accommodating space to reach a preset proportion;

after the ventilation device is turned on, the gas environment in the accommodating space 308 changes greatly, and oxygen in the refrigerating space 901 enters into the accommodating space 308. After the ventilation device is closed, the nitrogen generation device is started, and nitrogen is filled into the accommodating space 308, so that the volume concentration of oxygen in the accommodating space 308 reaches the preset concentration again.

Step S1060: and refrigerating the fruits and vegetables in the accommodating space at the set temperature.

And continuously refrigerating the fruits and vegetables at a set temperature under the preset concentration. As one skilled in the art will appreciate, timed ventilation is a repetitive process. However, when the user takes the fruits and vegetables, the storage time does not reach the first preset time, and the method may not perform steps S1040, S1050, and S1060, but still fall within the protection scope of the present invention.

According to the fruit and vegetable fresh-keeping method provided by the first embodiment of the invention, the vacuum pre-cooling is carried out by controlling the vacuumizing device, so that the environmental heat and the fruit and vegetable respiration heat of the accommodating space 308 can be rapidly eliminated; the volume concentration of oxygen in the accommodating space 308 is adjusted by controlling the nitrogen generating device, so that the fruits and vegetables are kept in the optimal fresh-keeping storage environment; through the closed design of the accommodating space 308, the high humidity of the accommodating space 308 can be maintained, the RH is maintained at about 85-95%, and the dynamic maintaining time of the fresh-keeping optimal gas component interval can be prolonged; in addition, the fruits and vegetables can also perform a small amount of respiration in the low-oxygen low-temperature environment refrigeration process to generate ethylene, ethanol and other harmful gases, and the harmful gases are regularly discharged through timing ventilation, so that the fresh-keeping time of the fruits and vegetables can be further prolonged, and the fresh-keeping effect is improved.

Referring to fig. 11, as a second embodiment of the method for refreshing fruits and vegetables based on the refrigerator 900 of the present invention, an oxygen sensor is disposed in the accommodating space, and steps S1020 and S1050 include the following steps:

step S1110: and acquiring the volume concentration of the oxygen in the accommodating space, and controlling the nitrogen generating device to be closed when the volume concentration of the oxygen reaches a preset proportion.

An oxygen sensor (not shown in the figure) is arranged in the accommodating space 308, the controller controls the operation of the nitrogen generating device according to the volume concentration of oxygen measured by the oxygen sensor, and when the volume concentration of oxygen reaches a preset proportion, namely the volume concentration of oxygen is 1% -15%, the nitrogen generating device is controlled to be closed. It should be noted that the oxygen sensor may also be configured as a nitrogen sensor, and when the oxygen sensor is configured as a nitrogen concentration sensor, the volume concentration of oxygen may be indirectly obtained.

Referring to fig. 12, as a third embodiment of the method for keeping fruits and vegetables fresh based on the refrigerator 900 of the present invention, steps S1020 and S1050 include the following steps:

step 1210: and controlling the time length for filling the nitrogen-rich gas into the accommodating space to a third preset time length so as to enable the volume concentration of the oxygen in the accommodating space to reach a preset proportion and control the nitrogen generating device to be closed.

In some embodiments, the accommodating space may not be provided with an oxygen sensor to monitor the volume concentration of the oxygen, and the nitrogen-rich gas filled into the accommodating space may be controlled by controlling the working time of the nitrogen generating device, that is, the third preset time period, so that the volume concentration of the oxygen in the accommodating space reaches the preset proportion, that is, the volume concentration of the oxygen is 1% to 15%, and then the nitrogen generating device is controlled to be turned off. It should be noted that the third preset time period may be obtained according to a previous test or a certain algorithm, and variables of the algorithm include the sealing property of the fresh-keeping box body, the volume of the accommodating space, the nitrogen volume concentration of the nitrogen-rich gas, the charging flow rate of the nitrogen-rich gas, and the like.

Referring to fig. 13, a controller 1300 according to the third aspect of the present invention, the controller 1300 may be any type of control module, such as a control board, a control box, a control chip, etc.

Specifically, the controller 1300 includes: one or more processors 1301 and a memory 1302, one processor 1301 and memory 1302 being exemplified in fig. 13. The processor 1301 and the memory 1302 may be connected by a bus 1303 or otherwise, as exemplified by the bus 1403 in fig. 13.

The memory 1302, as a non-transitory computer readable storage medium, can be used to store a non-transitory software program and a non-transitory computer executable program, such as the fruit and vegetable fresh-keeping method in the second embodiment of the present invention. The processor 1301 executes the non-transitory software program and the instructions stored in the memory 1302, so as to implement the fruit and vegetable fresh-keeping method in the second embodiment of the present invention.

The memory 1302 may include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application program required for at least one function; the storage data area can store data and the like required for executing the fruit and vegetable fresh-keeping method in the second aspect of the invention. Further, the memory 1302 may include high speed random access memory and may also include non-transitory memory, such as at least one magnetic disk storage device, flash memory device, or other non-transitory solid state storage device. In some embodiments, memory 1302 may optionally include memory located remotely from the processor, which may be connected to the terminal through a network. Examples of such networks include, but are not limited to, the internet, intranets, local area networks, mobile communication networks, and combinations thereof.

The non-transitory software program and instructions required for implementing the fruit and vegetable fresh-keeping method in the second aspect of the present invention are stored in the memory 1302, and when being executed by the one or more processors 1301, the fruit and vegetable fresh-keeping method in the second aspect of the present invention is executed, for example, the method steps S1010 to S1040 in fig. 10, the method step S1110 in fig. 11, and the method step S1210 in fig. 12 described above are executed.

Referring to fig. 14, there is shown a refrigerator 900 according to a fourth aspect of the present invention, including a controller 1300 according to the third aspect of the present invention.

In a fifth aspect of the present invention, a computer-readable storage medium is provided, which stores computer-executable instructions, which are executed by one or more control processors 1301, for example, by one of the processors 1301 in fig. 13, and can cause the one or more processors 1301 to perform the above-described method steps S1010 to S1040 in fig. 10, method step S1110 in fig. 11, and method step S1210 in fig. 12.

The above-described embodiments of the apparatus are merely illustrative, wherein the units illustrated as separate components may or may not be physically separate, i.e. may be located in one place, or may also be distributed over a plurality of network elements. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment.

One of ordinary skill in the art will appreciate that all or some of the steps, systems, and methods disclosed above may be implemented as software, firmware, hardware, and suitable combinations thereof. Some or all of the physical components may be implemented as software executed by a processor 1301, such as a central processing unit, a digital signal processor or a microprocessor, or as hardware, or as an integrated circuit, such as an application specific integrated circuit. Such software may be distributed on computer readable media, which may include computer storage media (or non-transitory media) and communication media (or transitory media). The term computer storage media includes volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data, as is well known to those of ordinary skill in the art. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, Digital Versatile Disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can accessed by a computer. In addition, communication media typically embodies computer readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism and includes any information delivery media as known to those skilled in the art.

While embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that: the above are only preferred embodiments of the present invention, which are intended to show the outstanding technical effects and advantages of the present invention, and are not intended to limit the technical solutions of the present invention. It should be understood by those skilled in the art that all modifications, changes or alternative technical features made based on the technical contents of the present invention should be included in the technical scope of the appended claims.

Claims

1. The fruit and vegetable fresh-keeping method based on the refrigerator is characterized in that the refrigerator comprises the following steps: the air-conditioning preservation box body is arranged in a refrigerating chamber of the refrigerator and is provided with a closed accommodating space for accommodating fruits and vegetables; a modified atmosphere generating device connected to the fresh keeping box body, the modified atmosphere generating device comprising:

the shell is provided with an air outlet which is used for communicating the accommodating space;

a vacuum pump having a pump inlet pipe and a pump outlet pipe;

the adsorption cylinder is internally provided with an oxygen adsorbent, the adsorption cylinder is provided with a cylinder air inlet pipe and a cylinder air outlet pipe, the cylinder air inlet pipe is simultaneously connected with the pump air inlet pipe and the pump air outlet pipe, a first three-way valve and a third three-way valve are sequentially connected between the cylinder air inlet pipe and the pump air inlet pipe, a second three-way valve is connected between the cylinder air inlet pipe and the pump air outlet pipe, the first three-way valve and the second three-way valve are both communicated with the refrigerating chamber, and the third three-way valve is connected with the air outlet;

the nitrogen storage tank is provided with a tank inlet pipe and a tank outlet pipe, the tank inlet pipe is communicated with the cylinder outlet pipe, and the tank outlet pipe is communicated with the gas outlet;

the air exchange device is arranged on the air-conditioning preservation box body and can open or close the communication between the accommodating space and the refrigerating chamber;

the fruit and vegetable fresh-keeping method comprises the following steps:

controlling the vacuum pump to vacuumize the accommodating space;

controlling the vacuum pump to inject air with a certain positive pressure into the adsorption cylinder in a controlled manner, wherein the oxygen adsorbent adsorbs oxygen in the injected air; the prepared nitrogen enters the nitrogen storage tank from the gas outlet, and the tank gas outlet pipe fills nitrogen-rich gas into the accommodating space, so that the volume concentration of oxygen in the accommodating space reaches a preset proportion, and the volume concentration of nitrogen in the nitrogen-rich gas is more than 90 vol.%;

controlling the vacuum pump to inject air with a certain positive pressure into the adsorption cylinder in a controlled manner, wherein the oxygen adsorbent adsorbs oxygen in the injected air; the prepared nitrogen enters the nitrogen storage tank from the gas outlet, and the tank gas outlet pipe fills nitrogen-rich gas into the accommodating space so that the volume concentration of oxygen in the accommodating space reaches the preset proportion;

2. The fruit and vegetable fresh-keeping method based on the refrigerator as claimed in claim 1, wherein the set temperature is as follows: -1 ℃ to 4 ℃.

3. The fruit and vegetable fresh-keeping method according to claim 1, characterized in that the preset proportion is as follows: 1 vol.% to 15 vol.%.

4. The method for preserving fruits and vegetables according to any one of claims 1 to 3, wherein an oxygen sensor is arranged in the accommodating space, and the filling of the accommodating space with the nitrogen-rich gas to make the volume concentration of the oxygen in the accommodating space reach a preset proportion comprises the following steps:

and acquiring the volume concentration of the oxygen in the accommodating space, and controlling the vacuum pump to stop injecting air with certain positive pressure into the adsorption cylinder when the volume concentration of the oxygen reaches the preset proportion.

5. The fruit and vegetable fresh-keeping method according to any one of claims 1 to 3, wherein the filling of the accommodating space with nitrogen-rich gas to make the volume concentration of oxygen in the accommodating space reach a preset ratio comprises:

and controlling the time length for filling the nitrogen-rich gas into the accommodating space to a third preset time length so that the volume concentration of the oxygen in the accommodating space reaches the preset proportion, and controlling the vacuum pump to stop injecting air with a certain positive pressure into the adsorption cylinder.

6. A controller for a refrigerator, comprising: a memory, a processor and a computer program stored on the memory and operable on the processor, the processor implementing the method of any of claims 1 to 5 when executing the program.

7. A refrigerator characterized by comprising the controller according to claim 6.

8. Computer-readable storage media storing computer-executable instructions, wherein the computer-executable instructions are configured to perform the method of preserving fruits and vegetables according to any one of claims 1 to 5.