A gas composition control system and method for physical preservation

Abstract

The application discloses a kind of gas component control system and method for physical preservation, it is related to gas component control technical field;Method includes: the oxygen concentration data and carbon dioxide concentration data of different positions in cabin, fruit respiration rate, stacking structure and gap size data, ventilation air distribution data and ethylene concentration are obtained by collection;Based on the sampling point of oxygen concentration data and carbon dioxide concentration data of different positions in cabin, determine intersection area;Based on the current oxygen concentration, current carbon dioxide concentration, predicted concentration and preset target gas concentration threshold value of each intersection area, determine to obtain the intersection area that has exceeded safety threshold and is close to critical;The application reduces the influence of substantial regulation frequency and gas concentration sudden change on the quality of stored goods by early intervention in the area close to critical and adjusting control parameters in stages, improves the stability and reliability of gas composition control of controlled atmosphere storage equipment.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of gas component control, and more particularly to a gas component control system and method for physical preservation. BACKGROUND

[0002] In the field of gas component control of controlled atmosphere storage equipment, in order to realize stable regulation and control of key gas components in a closed space and meet the gas environment requirements under specific storage scenarios, the industry generally uses a controlled atmosphere preservation cabin as the core controlled equipment. Such equipment usually stacks the containers to be stored in multiple layers and multiple columns in the form of regular containers, the stacking height can reach several meters, and the stacking gap is set to several centimeters to more than ten centimeters according to the container specifications. A single gas mixing device and a ventilation module are arranged on the side wall or top of the cabin body. The gas mixing device is used to adjust the injection proportion of key gases such as oxygen and carbon dioxide in the cabin, and the ventilation module is used to promote the circulation of the gas in the cabin. The two work together to maintain the stability of the gas components in the cabin. The core principle of the existing gas component control technology of the controlled atmosphere preservation cabin is to arrange a single gas sensor near the middle side wall or the top ventilation port inside the cabin body, to collect real-time oxygen concentration, carbon dioxide concentration and other data at this fixed position. The single-point concentration signal collected is transmitted to the controller as a control input. The controller generates a control instruction based on the preset gas concentration threshold or simple proportional control logic to drive the gas mixing device to adjust the injection amount of nitrogen and oxygen, and at the same time controls the ventilation module to run to realize the preliminary circulation of the gas in the cabin, so as to maintain the gas components at the sensor collection position within the target range, trying to indirectly realize the whole-cabin gas environment standard through local concentration stability.

[0003] However, the gas component control technology has significant limitations in practical application, and the root cause lies in that the existing control technology assumes that the gas components in the cabin are uniformly distributed, ignoring the influence of the stacking structure and airflow characteristics in the controlled equipment on the gas distribution, resulting in a deviation between the control input data and the actual state of the controlled object. On the one hand, during the stacking process, the stacking body formed by the regular containers has complex gap channels, and the bottom stacking area has narrower gap channels and greater airflow resistance than the top and side areas due to the pressure from the upper stacking, so that the oxygen replenishment rate of the bottom area is lower than the consumption rate, and the carbon dioxide discharge rate is lower than the generation rate, forming a vertical concentration gradient with high carbon dioxide concentration and low oxygen concentration at the bottom. On the other hand, the ventilation modules configured by the existing control technology are mostly designed with a top-mounted or side-mounted single air port, and the airflow coverage in the cabin is limited, making it difficult to penetrate the multi-layer stacking body to reach the deep area, and only local airflow circulation can be formed near the ventilation port, resulting in differences in gas concentration at different positions in the cabin, and carbon dioxide accumulation in the stacking area far from the ventilation port, while the gas components near the ventilation port are closer to the target value. In this case, a single sensor can only collect local gas concentration data at its installation position, and cannot fully reflect the overall gas distribution state in the cabin, resulting in a deviation between the control input signal obtained by the controller and the actual multi-region gas concentration in the cabin, and destroying the matching between the control logic and the state of the controlled object.

[0004] Since the control input signal cannot accurately capture the concentration abnormalities in the local area of the cabin, when the oxygen is too low or the carbon dioxide is too high in the bottom or the stacking area far from the ventilation port, the controller will still maintain the original control strategy based on the normal concentration signal at a single point, and will not start the adjustment action for the abnormal area, resulting in that the control action cannot cover the key abnormal area, and the gas environment in the local area of the cabin deviates from the target range for a long time. Such control failure can affect the quality of the to-be-stored materials, such as causing anaerobic respiration and generating harmful substances to cause quality deterioration, and can also cause a chain reaction due to the deterioration of the gas state in the local abnormal area, such as accelerating the state deterioration of the surrounding area due to the release of characteristic gases from the deteriorated to-be-stored materials, ultimately leading to a decrease in the overall storage effect of the cabin, increasing the storage loss cost, causing economic losses to the production enterprises, and exposing the deficiencies of the existing control technology in the state sensing, control action coverage and decision accuracy of the controlled object.

[0005] In view of this, the present application provides a gas component control system and method for physical preservation to solve the above problems. SUMMARY

[0006] In order to overcome the above-mentioned defects of the prior art and achieve the above-mentioned purposes, the present application provides the following technical solutions: a gas component control method for physical preservation, comprising:

[0007] Collect oxygen concentration data and carbon dioxide concentration data at different positions in the cabin, fruit respiration rate, stack structure and gap size data, ventilation air flow distribution data and ethylene concentration;

[0008] Based on the sampling points of oxygen concentration data and carbon dioxide concentration data at different positions in the cabin, determine the intersection area;

[0009] Based on the stack structure, gap size data and ventilation air flow distribution data, determine whether the intersection area is a ventilation dead angle;

[0010] Based on the current oxygen concentration, current carbon dioxide concentration, predicted concentration and preset target gas concentration threshold of each intersection area, determine the intersection area that has exceeded the safety threshold and is close to the critical value;

[0011] According to the situation of each intersection area, formulate the corresponding adjustment strategy.

[0012] Further, the setting method of the sampling points of oxygen concentration data and carbon dioxide concentration data at different positions in the cabin comprises:

[0013] Determine the sampling layer in the vertical direction, take the overall height of the stack as the reference, divide it into three sampling layers: top, middle and bottom. The top sampling layer is set at the middle position between the top of the stack and the top of the storage cabin, the middle sampling layer is set at the center of the overall height of the stack, and the bottom sampling layer is set at the middle position between the bottom of the stack and the bottom of the storage cabin, and the bottom sampling layer avoids the airflow obstruction area caused by the stack support structure;

[0014] Determine the sampling area in the horizontal direction, take the ventilation port as the reference, divide it into three sampling areas: close to the ventilation port area, far from the ventilation port area and stack center area. The close-to-ventilation-port area is set within a certain distance range in front of the ventilation port outlet, the far-from-ventilation-port area is set at the farthest position from the ventilation port in the storage cabin, and the stack center area is set at the geometric center of the horizontal distribution of the stack;

[0015] Each intersection position of each sampling layer and each sampling area is provided with a sampling point.

[0016] Further, the determination method of the intersection area comprises:

[0017] The intersection area is the intersection position of the sampling layer and the sampling area;

[0018] In the vertical direction, the height range of each intersection area corresponds to the height interval of the vertical sampling layer to which it belongs. The height range of the top intersection area is the space interval between the top of the stack and the top of the storage cabin, the height range of the middle intersection area is the middle interval of the overall height of the stack, and the height range of the bottom intersection area is the space interval between the bottom of the stack and the bottom of the storage cabin. The height boundaries of each vertical interval are based on the layering boundaries of adjacent stack units in the stack structure.

[0019] In the horizontal direction, the planar range of each intersection region corresponds to the planar interval of the horizontal sampling region to which the intersection region belongs. The planar range of the intersection region near the air outlet region is the horizontal region covered by the air outlet of the air outlet region. The planar range of the intersection region in the central region of the stack is the planar region covering the geometric center of the horizontal distribution of the stack and at least one complete stack unit. The planar range of the intersection region far from the air outlet region is the horizontal region of the stack in the storage cabin farthest from the air outlet region and not overlapping with the edge of the stack. The length and width boundaries of each horizontal interval are based on the arrangement pitch of the stack units.

[0020] The intersection region as a whole is a three-dimensional space region surrounded by the height interval and the planar interval.

[0021] Further, the method for determining the intersection region that has exceeded the safety threshold and the intersection region close to the critical state comprises:

[0022] The target gas concentration threshold value includes an oxygen safety lower limit threshold value, a carbon dioxide safety upper limit threshold value, an oxygen near-critical threshold value range, and a carbon dioxide near-critical threshold value range.

[0023] When there is an intersection region in which the current oxygen concentration is lower than the oxygen safety lower limit threshold value or the current carbon dioxide concentration is higher than the carbon dioxide safety upper limit threshold value, it is determined that the corresponding intersection region is a current intersection region that exceeds the safety threshold.

[0024] When there is an intersection region in which the current oxygen concentration is in the oxygen near-critical threshold value range or the current carbon dioxide concentration is in the carbon dioxide near-critical threshold value range, it is determined that the corresponding intersection region is a current intersection region close to the critical state.

[0025] When there is an intersection region in which the predicted concentration is lower than the oxygen safety lower limit threshold value or higher than the carbon dioxide safety upper limit threshold value within a preset time in the future, it is determined that the corresponding intersection region is a future intersection region that will exceed the safety threshold.

[0026] When there is an intersection region in which the predicted concentration enters the oxygen near-critical threshold value range or the carbon dioxide near-critical threshold value range within a preset time in the future, it is determined that the corresponding intersection region is a future intersection region that will be close to the critical state.

[0027] The intersection region that has exceeded the safety threshold includes the current intersection region that exceeds the safety threshold and the future intersection region that will exceed the safety threshold. The intersection region close to the critical state includes the current intersection region close to the critical state and the future intersection region close to the critical state.

[0028] Further, the method for obtaining the predicted concentration comprises:

[0029] The predicted concentration includes the predicted oxygen concentration and the predicted carbon dioxide concentration.

[0030] The input parameters of each intersection region are substituted into the preset concentration change formula to calculate the predicted concentration after the future time step;

[0031] The input parameters of each intersection region include the current oxygen concentration, the current carbon dioxide concentration, the oxygen consumption per unit time, the carbon dioxide production per unit time of each intersection region, and the airflow exchange rate of each intersection region extracted from the ventilation airflow distribution data.

[0032] Further, the method for obtaining the oxygen consumption per unit time and the carbon dioxide production per unit time includes:

[0033] The oxygen consumption rate and the carbon dioxide release rate of unit mass of fruit per unit time under the current temperature, the current oxygen concentration, and the current carbon dioxide concentration are extracted from the fruit respiration rate;

[0034] The total mass of fruit in each intersection region is obtained by multiplying the corresponding stack volume of each intersection region by the fruit stack density;

[0035] The oxygen consumption per unit time of each intersection region is obtained by multiplying the oxygen consumption rate of unit mass of fruit per unit time by the total mass of fruit in each intersection region;

[0036] The carbon dioxide production per unit time of each intersection region is obtained by multiplying the carbon dioxide release rate of unit mass of fruit per unit time by the total mass of fruit in each intersection region.

[0037] Further, the method for determining whether the intersection region is a ventilation dead angle includes:

[0038] The corresponding stack gap size and the number of stack layers of each intersection region are extracted from the stack structure and gap size data;

[0039] The stack gap critical value and the number of stack layers critical value are set;

[0040] When the stack gap size of the intersection region is less than the stack gap critical value, or the number of stack layers is greater than the number of stack layers critical value, or the intersection region overlaps with the position of the stack support structure, the corresponding intersection region is determined to be an airflow blocked region;

[0041] When the airflow velocity value of the airflow blocked region is less than the set airflow velocity critical value, the corresponding airflow blocked region is determined to be in a ventilation dead angle. The airflow velocity value of the airflow blocked region is obtained through the ventilation airflow distribution data.

[0042] Further, the method for formulating corresponding adjustment strategies according to the conditions of each intersection region includes:

[0043] For the cross region close to the critical cross region, the oxygen flow is supplemented, the fan speed is increased, or the low-power operation mode of the carbon dioxide removal device is started according to the preset adjustment mode;

[0044] For the cross region where the oxygen concentration exceeds the safety threshold, corresponding measures are taken to reduce the oxygen concentration;

[0045] For the cross region where the carbon dioxide concentration exceeds the safety threshold, corresponding measures are taken to reduce the carbon dioxide concentration;

[0046] For the ventilation dead angle, the ventilation strategy is adjusted according to the preset mode.

[0047] Further, for the cross region where the oxygen concentration exceeds the safety threshold, the method of taking corresponding measures to reduce the oxygen concentration comprises:

[0048] The current oxygen concentration, the oxygen safety lower threshold, the oxygen target concentration threshold and the gas volume of the corresponding cross region are extracted, and the total deviation amount of the oxygen concentration of the corresponding cross region is calculated; the gas volume is the space volume of the corresponding cross region;

[0049] The oxygen consumption per unit time of the corresponding cross region is extracted, and the oxygen flow to be supplemented per unit time is calculated in combination with the preset oxygen supplement buffer coefficient;

[0050] According to the oxygen flow to be supplemented per unit time and the oxygen output of the gas mixing device, the total amount of oxygen to be supplemented is determined;

[0051] According to the oxygen flow to be supplemented per unit time, the opening adjustment range of the oxygen valve is determined;

[0052] If the nitrogen injection amount needs to be adjusted at the same time, the reduction range of the nitrogen flow is calculated according to the mixing ratio relationship between oxygen and nitrogen;

[0053] The air flow exchange rate and the air flow diffusion coefficient of the corresponding cross region are extracted from the ventilation air flow distribution data; the theoretical time required for additional oxygen diffusion to the corresponding cross region is calculated in combination with the spatial distance of the corresponding cross region and the preset air flow diffusion coefficient; the spatial distance of the corresponding cross region is the shortest path length from the air outlet of the gas mixing device to the corresponding cross region;

[0054] The actual duration is calculated in combination with the oxygen consumption per unit time of the corresponding cross region.

[0055] Further, for the cross region where the carbon dioxide concentration exceeds the safety threshold, the method of taking corresponding measures to reduce the carbon dioxide concentration comprises:

[0056] Based on the current carbon dioxide concentration, the carbon dioxide safety upper threshold value and the gas volume of the corresponding intersection area, the total amount of carbon dioxide to be reduced in the intersection area where the carbon dioxide concentration exceeds the safety threshold value is calculated;

[0057] If the carbon dioxide removal device is equipped, the device operation parameters are adjusted according to the unit time processing capacity of the carbon dioxide removal device until the amount of carbon dioxide to be reduced is reached.

[0058] If the carbon dioxide removal device is not equipped, when the short-time cabin pressure reduction method is used, the pressure reduction amplitude is calculated according to the total amount of carbon dioxide to be reduced and the initial cabin pressure obtained in advance; when the directional ventilation method is used, the ventilation port of the corresponding direction is opened according to the position of the corresponding intersection area, and the ventilation fan speed is adjusted to the preset high speed gear.

[0059] A gas component control system for physical preservation, comprising:

[0060] A data acquisition module is configured to acquire oxygen concentration data and carbon dioxide concentration data at different positions in the cabin, fruit respiration rate, stack structure and gap size data, ventilation airflow distribution data and ethylene concentration.

[0061] A region division module is configured to determine intersection areas based on sampling points of oxygen concentration data and carbon dioxide concentration data at different positions in the cabin.

[0062] A first determination module is configured to determine whether the intersection area is a ventilation dead angle based on stack structure, gap size data and ventilation airflow distribution data.

[0063] A second determination module is configured to determine intersection areas that have exceeded the safety threshold value and are close to the critical value based on current oxygen concentration, current carbon dioxide concentration, predicted concentration and preset target gas concentration threshold value of each intersection area.

[0064] A strategy making module is configured to make corresponding adjustment strategies according to the conditions of each intersection area.

[0065] Compared with the prior art, the technical effects and advantages of the gas component control system and method for physical preservation of the present application are:

[0066] The present application collects oxygen concentration data, carbon dioxide concentration data, fruit respiration rate, stack structure and gap size data, ventilation airflow distribution data and ethylene concentration in different positions in the cabin through the data acquisition module, wherein the oxygen and carbon dioxide concentration sampling points cover the intersection positions of the vertical direction top, middle and bottom sampling layers and the horizontal direction close to the ventilation opening area, far from the ventilation opening area and the stack center area, to ensure coverage of the concentration difference area; the region division module determines the three-dimensional intersection area based on these sampling points, and clearly defines the vertical height interval and horizontal plane range of each region; the first determination module extracts the stack gap size and stack layer number of each intersection area in combination with the stack structure and gap size data, compares the critical value and judges whether it overlaps with the support structure to determine the airflow obstruction area, and then determines the ventilation dead angle in combination with the airflow velocity value in the ventilation airflow distribution data; the second determination module first estimates the oxygen consumption and carbon dioxide production per unit time of each intersection area based on the fruit respiration rate, substitutes it into the concentration change formula to obtain the future predicted concentration, and then combines the preset target gas concentration threshold to identify the intersection area that has exceeded the safety threshold and is close to the critical value through the double determination of the current concentration and the predicted concentration; the strategy making module formulates adjustment strategies for different regions, performs mild regulation on the area close to the critical value, calculates the oxygen supplement amount for the intersection area with oxygen exceeding the safety threshold and adjusts the gas mixing equipment in stages, removes the device, reduces the pressure or directional ventilation to reduce carbon dioxide for the intersection area with carbon dioxide exceeding the safety threshold, adjusts the ventilation strategy for the ventilation dead angle, and at the same time introduces safety redundancy to respond to concentration deviation in advance, and takes ventilation, purification or manual inspection measures according to the graded threshold for ethylene concentration anomaly.

[0067] The present application solves the problem that the gas component control technology of the existing controlled atmosphere storage equipment relies on a single-point sensor and cannot reflect the overall gas distribution in the cabin, ignores the influence of the stack structure and airflow characteristics on the gas distribution, resulting in local low oxygen or high carbon dioxide, and the limited coverage of the ventilation module makes the control effect unable to reach the ventilation dead angle, improves the defects that the control input signal does not match the actual state of the controlled object and the control effect is not comprehensive. The present application avoids the long-term deviation of the local gas environment from the target range, which causes the stored material to be in an unsuitable gas environment, leading to anaerobic respiration and the production of harmful substances, causing quality deterioration, and prevents the release of ethylene by the local deteriorated stored material, which accelerates the ripening and aging of the surrounding stored material, effectively improves the overall storage effect of the cabin, reduces the storage loss cost, and ensures the long-term storage quality of the stored material. In addition, the regulation and control strategy of the present application is accurate and forward-looking, which reduces the frequency of large-scale regulation and control and the influence of sudden changes in gas concentration on the quality of the stored material by intervening in the area close to the critical value in advance and adjusting the control parameters in stages, thereby improving the stability and reliability of the gas component control of the controlled atmosphere storage equipment. BRIEF DESCRIPTION OF DRAWINGS

[0068] Figure 1This is a schematic diagram of a gas component control system for physical preservation according to an embodiment of the present invention.

[0069] Figure 2 This is a flowchart of a gas component control method for physical preservation according to an embodiment of the present invention;

[0070] Figure 3 This is a schematic diagram of the sampling points and overlapping areas of oxygen concentration data and carbon dioxide concentration data at different locations inside the cabin according to an embodiment of the present invention;

[0071] Figure 4 A flowchart illustrating the method for determining the intersection region that has exceeded the safety threshold and is close to the critical point in this embodiment of the invention;

[0072] Figure 5 This is a flowchart illustrating a method for determining whether an intersection area is a ventilation dead zone according to an embodiment of the present invention. Detailed Implementation

[0073] The technical solutions of the embodiments of the present invention will be described in detail, clearly, and completely below with reference to the accompanying drawings. It should be particularly noted that the specific embodiments described below are only for better illustrating and explaining the technical solutions of the present invention, and are intended to enable those skilled in the art to better understand and implement the present invention, and should not be construed as limiting the scope of protection of the present invention. Without departing from the spirit and substance of the present invention, those skilled in the art can modify, adjust, or make equivalent substitutions based on the content disclosed in the present invention, and these should all be considered within the scope of protection of the present invention.

[0074] Example 1:

[0075] Please see Figure 1 As shown, this embodiment discloses a gas composition control system for physical preservation, including a data acquisition module, a region division module, a first determination module, a second determination module, and a strategy formulation module. Each module is connected via wired and / or wireless means to achieve data transmission.

[0076] The data acquisition module is used to collect oxygen and carbon dioxide concentration data, fruit respiration rate, stacking structure and gap size data, ventilation airflow distribution data, and ethylene concentration at different locations inside the cabin.

[0077] Please see Figure 3 As shown, the sampling points used to collect oxygen concentration data at different locations inside the chamber need to cover areas where gas concentrations within the storage chamber are prone to differences. The specific setup method is as follows:

[0078] Due to the stacking structure and airflow characteristics in the storage cabin, there are significant differences in gas concentration in different areas. In the vertical direction, the oxygen replenishment rate is lower than the consumption rate, and the carbon dioxide discharge rate is lower than the generation rate in the bottom stacking area due to the narrow gap channel, high gas flow resistance, and pressure from the upper stacking. The gas state in the top and middle areas is significantly different. In the horizontal direction, the airflow covers the area near the ventilation port fully, and the gas is updated quickly. The area far from the ventilation port and the center of the stack is prone to gas accumulation due to insufficient airflow penetration. Therefore, the sampling points need to be set in the following way to accurately capture these differences.

[0079] First, determine the vertical sampling layer. Divide the top, middle, and bottom sampling layers based on the overall height of the stack. The top sampling layer is set at the middle position between the top of the stack and the top of the storage cabin. The middle sampling layer is set at 1 / 2 of the overall height of the stack. The bottom sampling layer is set at the middle position between the bottom of the stack and the bottom of the storage cabin, and it needs to avoid the airflow obstruction area caused by the stack support structure. Second, determine the horizontal sampling area. Divide the area near the ventilation port, the area far from the ventilation port, and the center of the stack into three sampling areas based on the ventilation port. The area near the ventilation port is set within 1 meter in front of the ventilation port outlet. The area far from the ventilation port is set at the farthest distance from the ventilation port in the storage cabin. The center of the stack is set at the geometric center of the horizontal distribution of the stack. Each sampling layer and each sampling area are set with a sampling point. If the volume of the storage cabin exceeds 50 cubic meters, a transition sampling point can be added between the center of the stack and the area far from the ventilation port to ensure coverage of all areas where concentration differences may occur.

[0080] Install oxygen sensors at each sampling point to monitor oxygen concentration in real time. If only a single sensor is available, multiple sampling lines and a switching valve can be set up to sequentially extract gas samples from each sampling area and send them to the sensor for measurement to obtain the oxygen concentration at each location. To avoid the lag of single-sensor multi-channel sampling, a reasonable sampling interval should be set, with each area's sampling interval not exceeding 30 seconds. Fixed sensors should be deployed preferentially in areas such as the bottom and ventilation dead zones. The advantages of this design are: 1) It can fully cover the areas where gas concentration differences are likely to occur in the storage cabin, avoiding the problem of single-point sampling reflecting only local conditions and not representing the overall gas distribution. 2) By setting the intersection of sampling layers and sampling areas, the oxygen concentration status of different three-dimensional space areas can be accurately captured, providing clear data collection basis for subsequent cross-area determination. 3) When the volume exceeds 50 cubic meters, a transition sampling point is added to further eliminate monitoring blind spots. 4) Fixed sensors are deployed preferentially in areas such as the bottom and ventilation dead zones, and the sampling interval is controlled, which can reduce data delay and ensure that oxygen concentration data at different locations in the cabin are timely and accurate, laying a reliable data foundation for subsequent ventilation dead zone determination, gas distribution analysis, and control strategy development.

[0081] The sampling point setting method of carbon dioxide concentration data at different positions in the cabin is completely consistent with the sampling point setting method of oxygen concentration data at different positions in the cabin, that is, the same is to divide the top, middle and bottom three vertical sampling layers based on the stacking height, divide the area close to the ventilation port, the area far from the ventilation port and the stacking center area into three horizontal sampling areas based on the ventilation port, set sampling points at the intersection position of each sampling layer and each sampling area, and add transition sampling points when the volume exceeds 50 cubic meters. Carbon dioxide sensors are installed at each sampling point or multi-channel sampling is used to measure the carbon dioxide concentration of each area to ensure that the carbon dioxide level at different parts of the stack is mastered. In order to avoid the hysteresis of single sensor multi-channel sampling, the sampling interval of each area also needs to be set to no more than 30 seconds, and fixed sensors are preferentially deployed in the bottom, ventilation dead angle and other areas. The design of the sampling points can make the carbon dioxide concentration data at different positions in the cabin correspond to the oxygen concentration data at different positions in the cabin, and together fully reflect the state of the gas components in each area, providing comprehensive data support for subsequent determination of the cross-over area exceeding the safety threshold or approaching the critical value and the development of targeted adjustment strategies.

[0082] The fruit respiration rate is the respiration metabolic intensity of the stored fruit variety under a specific temperature, oxygen and carbon dioxide environment, that is, the oxygen consumption rate and carbon dioxide release rate per unit mass of fruit. The corresponding data can be obtained by measuring the amount of oxygen decrease and carbon dioxide increase per unit time in a sealed container experiment.

[0083] The stacking structure and gap size data are the size of the fruit box or basket, the number of stacking layers, the row and column arrangement, and the average gap size between the stacks and the boxes. These data are obtained by measuring the box size, stacking method, and combining the stacking deformation test under pressure.

[0084] The ventilation air flow distribution data is obtained by measuring the air flow velocity and coverage range in the cabin when the ventilation device is running. For example, a wind speed meter, multi-point smoke test or CFD simulation can be used to obtain the wind speed, wind path direction and depth area that can be penetrated by air flow at different positions under empty cabin conditions to understand the coverage of the existing single air vent ventilation.

[0085] The ethylene concentration is the content of ethylene gas in the cabin air, which is monitored regularly by using ethylene sensors such as electrochemical or optical detection instruments. Ethylene is a gas released when fruits ripen and rot, and its concentration data can be used to early warn the deterioration of fruits in the stack.

[0086] The control system collects gas readings of each measuring point from the cabin sensor, obtains oxygen concentration data at different positions in the cabin and carbon dioxide concentration data at different positions in the cabin. Each measuring point is determined according to the oxygen concentration data sampling point setting method at different positions in the cabin to ensure that the top, middle and bottom three vertical sampling layers and the area close to the ventilation port, the area far from the ventilation port and the center area of the stack are covered. At the same time, the temperature, humidity and ethylene concentration of the current environment are collected. If a single sensor is used for multi-channel sampling, the sampling area is switched at an interval of not more than 30 seconds for each area to ensure the timeliness of the data.

[0087] The area division module determines the cross region based on the sampling points of the oxygen concentration data and the carbon dioxide concentration data at different positions in the cabin.

[0088] Referring to Figure 3 As shown, the cross region refers to the intersection of the top, middle and bottom three vertical sampling layers and the area close to the ventilation port, the area far from the ventilation port and the center area of the stack. In the vertical direction, the height range of each cross region corresponds to the height interval of the vertical sampling layer to which it belongs. The height range of the top cross region is the space interval between the top end of the stack and the top of the storage cabin. The height range of the middle cross region is the middle interval of the overall height of the stack. The height range of the bottom cross region is the space interval between the bottom end of the stack and the bottom of the storage cabin. The height boundaries of each vertical interval are based on the layering boundaries of adjacent stack units in the stack structure. In the horizontal direction, the plane range of each cross region corresponds to the plane interval of the horizontal sampling area to which it belongs. The plane range of the cross region close to the ventilation port is the horizontal area of the stack covered by the air outlet of the ventilation port. The plane range of the cross region in the center area of the stack is the plane area covering at least one complete stack unit around the geometric center of the horizontal distribution of the stack. The plane range of the cross region far from the ventilation port is the horizontal area of the stack in the storage cabin farthest from the ventilation port and without overlapping with the edges of the stack. The length and width boundaries of each horizontal interval are based on the arrangement spacing of the stack units. The overall cross region is a three-dimensional space region surrounded by the vertical height intervals and horizontal plane intervals described above, and its spatial range needs to completely cover the stack units at the corresponding position to ensure that the gas flow state of the corresponding local stack area can be reflected.

[0089] The first determination module determines whether the cross region is a ventilation dead angle based on the stack structure, gap size data and ventilation airflow distribution data.

[0090] Referring to Figure 5As shown, the stack gap size and the number of stacks corresponding to each intersection region are extracted from the stack structure and gap size data; the stack gap critical value and the number of stack critical value are set, for example, the stack gap critical value is set to 5mm, and the number of stack critical value is set to 8 layers; the stack gap size of each intersection region is compared with the stack gap critical value, and the number of stacks is compared with the number of stack critical value, while judging whether each intersection region overlaps with the position of the stack support structure; when the stack gap size of the intersection region is less than the stack gap critical value, or the number of stacks is greater than the number of stack critical value, or the intersection region overlaps with the position of the stack support structure, it is determined that the corresponding intersection region is an airflow blocked region.

[0091] The airflow blocked region is confirmed whether it is in the ventilation dead angle by using the ventilation airflow distribution data, and the confirmation process is to extract the airflow velocity value corresponding to each airflow blocked region in the ventilation airflow distribution data, and set the airflow velocity critical value to 0.1m / s, when the airflow velocity value of the airflow blocked region is less than the airflow velocity critical value, it is determined that the corresponding airflow blocked region is in the ventilation dead angle.

[0092] The second determination module determines the intersection region that has exceeded the safety threshold and is close to the critical value based on the current oxygen concentration, the current carbon dioxide concentration, the predicted concentration and the preset target gas concentration threshold of each intersection region.

[0093] The oxygen consumption and carbon dioxide production of fruits in each intersection region are estimated by combining the fruit respiration rate, and the method comprises: extracting the oxygen consumption rate and carbon dioxide release rate of unit mass of fruit per unit time under the current temperature, current oxygen concentration and current carbon dioxide concentration from the fruit respiration rate; calculating the total mass of fruits in each intersection region according to the stack structure data, wherein the stack structure data is a component of the stack structure and gap size data, and specifically includes the size of the fruit box / basket, the number of stacks, the row and column arrangement and the relative position relationship between the stacks, and the calculation method is that the stack volume corresponding to each intersection region is multiplied by the fruit stack density, wherein the stack volume is the space volume of the intersection region multiplied by the preset stack filling coefficient, and the stack filling coefficient is determined by: determining the single-box occupied space according to the size specification of the fruit box / basket, calculating the theoretical filling proportion in combination with the staggered stacking or aligned stacking and other stacking methods, and calibrating by referring to the actual storage filling data of similar fruits under the same stacking method, while considering the morphological characteristics of fruits to avoid damage caused by extrusion, and finally determining the stack filling coefficient; the fruit stack density is the standard stack density value of the corresponding variety of fruits; the oxygen consumption of each intersection region per unit time is obtained by multiplying the oxygen consumption rate of unit mass of fruit per unit time by the total mass of fruits in each intersection region; the carbon dioxide production of each intersection region per unit time is obtained by multiplying the carbon dioxide release rate of unit mass of fruit per unit time by the total mass of fruits in each intersection region.

[0094] The predicted concentration at the future time step is predicted, and the prediction method comprises: substituting the input parameters of each intersection region into a preset concentration change formula to calculate the predicted concentration after the future time step, the input parameters including the current oxygen concentration, the current carbon dioxide concentration, the oxygen consumption per unit time and the carbon dioxide generation per unit time of each intersection region, and the airflow exchange rate of each intersection region extracted from the ventilation airflow distribution data; the concentration change formula is derived based on the law of conservation of mass, the oxygen concentration change formula is: ΔOxygen = (airflow exchange carried oxygen amount-oxygen consumption amount) / intersection region gas volume x Δt, the carbon dioxide concentration change formula is: ΔCarbon dioxide = (carbon dioxide generation amount-airflow exchange carried carbon dioxide amount) / intersection region gas volume x Δt, wherein Δt is the prediction time step, which can be set to 5 minutes for example, ΔOxygen is the oxygen concentration change amount in the prediction time step, and ΔCarbon dioxide is the carbon dioxide concentration change amount in the prediction time step; the airflow exchange carried oxygen amount is the airflow exchange rate multiplied by the external oxygen concentration, the airflow exchange carried carbon dioxide amount is the airflow exchange rate multiplied by the current carbon dioxide concentration, and the intersection region gas volume is the space volume of the intersection region; the input parameters of each intersection region are substituted into the concentration change formula to calculate the oxygen concentration and the carbon dioxide concentration after each time step, for example, 12 time steps are calculated continuously to obtain the oxygen and carbon dioxide concentration change trend of each intersection region within 1 hour in the future.

[0095] Please refer to Figure 4 As shown, the current concentration, the predicted concentration within the preset time length in the future and the set target gas concentration threshold of each intersection region are combined to determine the intersection region that has exceeded the safety threshold and is close to the critical value, and the specific determination process is as follows:

[0096] The target gas concentration threshold includes an oxygen safety lower limit threshold, a carbon dioxide safety upper limit threshold, an oxygen near-critical threshold range and a carbon dioxide near-critical threshold range, and the setting method of each threshold is as follows:

[0097] The setting method of the oxygen safety lower limit threshold is: first, extract the oxygen concentration lower limit basic value specified in the controlled atmosphere storage industry standard of the target fruit variety; second, determine the minimum oxygen concentration at which anaerobic respiration does not occur for the corresponding fruit variety through the anaerobic respiration test of the corresponding fruit variety, as the anaerobic respiration critical value; finally, combined with the storage period adjustment, when the storage period is longer, a preset safety factor is added on the basis of the larger value of the oxygen concentration lower limit basic value and the anaerobic respiration critical value, to ensure that anaerobic respiration is not triggered due to concentration fluctuation in long-term storage, and the oxygen safety lower limit threshold is set.

[0098] The setting method of the safe upper limit threshold of carbon dioxide is: first, extract the upper limit basic value of carbon dioxide concentration of the target fruit variety in the controlled atmosphere storage industry standard; then, through the carbon dioxide tolerance test of the corresponding fruit variety, determine the highest carbon dioxide concentration at which the fruit does not appear flesh browning, abnormal flavor and other quality deterioration as the carbon dioxide tolerance critical value; finally, refer to the historical data of the corresponding fruit quality problems caused by carbon dioxide accumulation in previous storage, take the smaller value of the upper limit basic value of carbon dioxide concentration and the carbon dioxide tolerance critical value, and add a preset risk coefficient to complete the setting of the safe upper limit threshold of carbon dioxide.

[0099] The setting method of the oxygen near-critical threshold range is: the lower limit of the oxygen near-critical threshold range is the set oxygen safe lower limit threshold, and the upper limit is the sum of the oxygen safe lower limit threshold and a preset critical deviation value; wherein, the preset critical deviation value is determined based on the following factors: first, the fluctuation range of oxygen concentration of the corresponding fruit variety in normal storage, to ensure that the deviation value covers the conventional fluctuation range; second, the oxygen concentration increase range that can be achieved by slight control measures such as small increase in oxygen injection amount, to ensure that after starting adjustment within the corresponding range, the concentration can be effectively prevented from falling below the oxygen safe lower limit threshold, and the oxygen near-critical threshold range is set.

[0100] The setting method of the carbon dioxide near-critical threshold range is: the upper limit of the carbon dioxide near-critical threshold range is the set carbon dioxide safe upper limit threshold, and the lower limit is the difference between the carbon dioxide safe upper limit threshold and a preset critical deviation value; wherein, the preset critical deviation value is determined based on the following factors: first, the fluctuation range of carbon dioxide concentration of the corresponding fruit variety in normal storage, to ensure that the deviation value covers the conventional fluctuation range; second, the carbon dioxide concentration decrease range that can be achieved by slight control measures such as small increase in ventilation, to ensure that after starting adjustment within the corresponding range, the concentration can be effectively prevented from rising to the carbon dioxide safe upper limit threshold, and the carbon dioxide near-critical threshold range is set.

[0101] The current oxygen concentration and the current carbon dioxide concentration of each intersection region are compared with the target gas concentration threshold data, and a determination is made by setting a near critical threshold range. The oxygen near critical threshold range is from the oxygen safety lower limit threshold to the sum of the oxygen safety lower limit threshold and a preset critical deviation value, and the carbon dioxide near critical threshold range is from the difference between the carbon dioxide safety upper limit threshold and a preset critical deviation value to the carbon dioxide safety upper limit threshold. When there is an intersection region whose current oxygen concentration is lower than the oxygen safety lower limit threshold or whose current carbon dioxide concentration is higher than the carbon dioxide safety upper limit threshold, the corresponding intersection region is determined to be a current safety threshold exceeding intersection region. When there is an intersection region whose current oxygen concentration is in the oxygen near critical threshold range or whose current carbon dioxide concentration is in the carbon dioxide near critical threshold range, the corresponding intersection region is determined to be a current near critical threshold intersection region. By comparing the current oxygen concentration and the current carbon dioxide concentration of each intersection region with the target gas concentration threshold data, the intersection regions that have already appeared concentration abnormalities or are on the verge of abnormalities are identified, and are preferentially processed in subsequent control.

[0102] The predicted concentrations of each intersection region within a future preset time period are extracted, and a determination is made according to the same near critical threshold range and safety threshold standard as described above. When there is an intersection region whose predicted concentration is lower than the oxygen safety lower limit threshold or higher than the carbon dioxide safety upper limit threshold within the future preset time period, the corresponding intersection region is determined to be a future safety threshold exceeding intersection region. When there is an intersection region whose predicted concentration enters the oxygen near critical threshold range or the carbon dioxide near critical threshold range within the future preset time period, the corresponding intersection region is determined to be a future near critical threshold intersection region. By extracting the predicted concentrations of each intersection region within a future preset time period to make a determination, intersection regions that are currently normal but may have abnormalities in the future are identified, and need to be intervened in advance in subsequent control to avoid further deterioration of the concentration.

[0103] The two types of determination results are integrated to form a complete list of intersection regions that have exceeded the safety threshold and are near the critical threshold. The intersection regions that have exceeded the safety threshold include the current safety threshold exceeding intersection regions and the future safety threshold exceeding intersection regions, and the intersection regions near the critical threshold include the current near critical threshold intersection regions and the future near critical threshold intersection regions. By combining the current concentration and the predicted concentration for determination, both the concentration abnormalities that have already occurred and the potential concentration risks can be responded to in advance, ensuring that the determination results comprehensively cover the current state and future trend of the cabin gas concentration, and providing complete basis for subsequent formulation of precise control strategies.

[0104] The strategy formulation module is configured to formulate corresponding adjustment strategies according to the conditions of each intersection region.

[0105] For the cross region with oxygen concentration close to the critical threshold, the oxygen valve opening degree is fine-tuned by 30%-50% of the oxygen flow rate required per unit time to slowly increase the oxygen concentration in the region; for the cross region with current carbon dioxide concentration in the range of carbon dioxide close to the critical threshold, the ventilation fan speed corresponding to the cross region is increased to 1.2-1.5 times of the conventional operation speed, or the low-power operation mode of the carbon dioxide removal device is started, through such early mild regulation and control, the concentration of the cross region close to the critical threshold is prevented from further deteriorating to exceed the safety threshold, the frequency and amplitude of subsequent large-scale regulation and control are reduced, and the impact of concentration sudden change on fruit quality is reduced.

[0106] For the intersection area where the oxygen concentration exceeds the safety threshold, the required oxygen supplement amount is calculated, and the calculation process specifically includes: extracting the current oxygen concentration of the corresponding intersection area, the lower limit threshold of oxygen safety, the target oxygen concentration threshold, and the gas volume of the corresponding intersection area, wherein the gas volume of the corresponding intersection area is the spatial volume of the intersection area; calculating the total deviation amount of the oxygen concentration of the corresponding intersection area, the total deviation amount of the oxygen concentration = (the target oxygen concentration threshold - the current oxygen concentration) × the gas volume of the corresponding intersection area; extracting the oxygen consumption amount of the corresponding intersection area per unit time, combining the preset oxygen supplement buffer coefficient, calculating the oxygen flow required to be supplemented per unit time, the oxygen flow required to be supplemented per unit time = (the oxygen consumption amount per unit time + the total deviation amount of the oxygen concentration / the preset oxygen supplement duration) × the oxygen supplement buffer coefficient; the preset method of the oxygen supplement buffer coefficient is: extracting the oxygen tolerance test data of the target fruit variety, determining the maximum fluctuation amplitude of the oxygen concentration that the corresponding fruit variety can withstand in a short time, ensuring that the oxygen concentration change during the oxygen supplement process does not exceed the fluctuation amplitude, and avoiding the impact on the fruit quality caused by the sudden increase of the concentration; combining the ventilation airflow distribution data, extracting the airflow exchange rate fluctuation range of the corresponding intersection area, if the airflow exchange rate fluctuation is large, the oxygen supplement buffer coefficient needs to be appropriately increased to cope with the oxygen diffusion difference caused by unstable airflow, if the airflow exchange rate is stable, the basic buffer coefficient can be maintained; referring to the response delay time of the gas mixing device, valve and other oxygen supplement related equipment, when the equipment response delay is longer, the oxygen supplement buffer coefficient is increased to compensate for the problem of insufficient oxygen supplement caused by delay, when the equipment response delay is shorter, the oxygen supplement buffer coefficient is set as the basic value; considering the above factors, the oxygen supplement buffer coefficient is preset to be in the range of 1.1-1.3, ensuring that the oxygen supplement process can quickly fill the oxygen gap, and can avoid local oxygen concentration exceeding the standard or insufficient oxygen supplement. According to the oxygen flow required to be supplemented per unit time and the oxygen output range of the gas mixing device, the total oxygen required to be supplemented is determined, the total oxygen required to be supplemented = the oxygen flow required to be supplemented per unit time × the preset oxygen supplement duration, and the required oxygen supplement amount calculation is completed.The fruit respiration rate data is used to estimate the oxygen gap of the corresponding intersection area per unit time. The gas mixing device is adjusted by the following technical features: according to the calculated oxygen flow rate to be supplemented per unit time, the adjustment range of the opening degree of the oxygen valve is determined, and the adjustment range of the opening degree of the oxygen valve = (oxygen flow rate to be supplemented per unit time / maximum oxygen output flow rate of the gas mixing device) × 100%; if the nitrogen injection amount needs to be adjusted at the same time, according to the mixing ratio relationship between oxygen and nitrogen, the reduction range of the nitrogen flow rate is calculated, and the reduction range of the nitrogen flow rate = (oxygen flow rate to be supplemented per unit time / mixing ratio coefficient of oxygen and nitrogen), so as to ensure that the total pressure of the gas in the cabin after adjustment is maintained within the preset range; a phased adjustment method is adopted, the opening degree of the oxygen valve is first adjusted to 60% to 80% of the calculated range, and maintained for a preset short time, then according to the real-time oxygen concentration change rate of the corresponding intersection area, it is gradually adjusted to the target opening degree, so as to avoid the sudden increase of oxygen concentration leading to local concentration exceeding the standard, and through the above adjustment, the overall oxygen concentration is slightly increased to make up for the shortage of remote areas. The duration of the opening of the oxygen valve is determined in combination with the ventilation airflow distribution data, and the specific method includes: extracting the airflow exchange rate and airflow diffusion coefficient of the corresponding intersection area from the ventilation airflow distribution data; calculating the theoretical time required for additional oxygen to diffuse to the corresponding intersection area, the theoretical time = the spatial distance of the corresponding intersection area / (airflow exchange rate × airflow diffusion coefficient), wherein the spatial distance of the corresponding intersection area is the shortest path length from the air outlet of the gas mixing device to the corresponding intersection area; in combination with the oxygen consumption of the corresponding intersection area per unit time, the actual duration is calculated, the actual duration = total oxygen to be supplemented / (oxygen flow rate to be supplemented per unit time + oxygen amount brought in by airflow exchange), so as to ensure that the actual duration is not less than the theoretical time, and to avoid poor oxygen supplementing effect due to insufficient diffusion, and through the above method, it is ensured that the additional oxygen can diffuse to the problem area.

[0107] The method for obtaining the air flow diffusion coefficient comprises: extracting the stack gap size, the stack unit material and the arrangement mode in the stack structure and the gap size data corresponding to the intersection area, and obtaining the current temperature and humidity data in the cabin, which directly affect the diffusion capacity of the gas in the stack gap; obtaining the initial air flow diffusion coefficient through experiment determination or CFD fluid dynamics simulation; in the experiment determination, releasing the tracer gas with a preset concentration in the simulation space consistent with the actual storage cabin stack environment, monitoring the diffusion speed of the tracer gas in the corresponding intersection area, and calculating the initial air flow diffusion coefficient according to the relationship between the diffusion distance and the time; in the CFD fluid dynamics simulation, inputting the stack gap size, the stack unit material, the temperature and humidity in the cabin and the ventilation air flow parameters into the simulation software, simulating the diffusion process of the gas in the corresponding intersection area, and outputting the initial air flow diffusion coefficient; combining the actual air flow speed of the corresponding intersection area in the ventilation air flow distribution data and the concentration change rate of the corresponding intersection area in the ventilation process, the initial air flow diffusion coefficient is calibrated, so that the calibrated air flow diffusion coefficient can accurately reflect the actual gas diffusion state.

[0108] For the cross region where the carbon dioxide concentration exceeds the safety threshold, the amount of carbon dioxide that needs to be reduced is determined, and the specific method includes: calculating the total amount of carbon dioxide that needs to be reduced in the cross region where the carbon dioxide concentration exceeds the safety threshold, total amount of carbon dioxide that needs to be reduced = (current carbon dioxide concentration - upper limit of carbon dioxide safety threshold) × gas volume of corresponding cross region; if a carbon dioxide removal device is provided, adjust the device operating parameters according to the unit time processing capacity of the carbon dioxide removal device: if the device is an adsorption type device such as a lime water absorption tower, increase the contact area between the adsorbent and the gas by opening multiple adsorption layers, or increase the speed of the gas flowing through the adsorbent, so that the unit time processing capacity of the device is increased to the calculated value, calculated value = (total amount of carbon dioxide that needs to be reduced / preset carbon reduction duration) × carbon reduction buffer coefficient, while monitoring the carbon dioxide concentration at the outlet of the device in real time, when the concentration decreases to the target carbon dioxide concentration threshold, adjust the parameters to the normal operating state; if no carbon dioxide removal device is provided, when using the short-time reduction cabin pressure method, calculate the pressure reduction amplitude according to the total amount of carbon dioxide that needs to be reduced and the initial pressure in the cabin, pressure reduction amplitude = (total amount of carbon dioxide that needs to be reduced / total gas volume in the cabin) × initial pressure, the pressure reduction process is maintained for a preset short time and then restored to normal pressure to ensure that the pressure reduction amplitude does not affect the quality of the fruits; when using the directional ventilation method, according to the position of the corresponding cross region, open the ventilation port in the corresponding direction, for example, if the corresponding cross region is close to the side of the cabin, open the side ventilation port, adjust the ventilation fan speed to the preset high wind speed gear, ventilation time = total amount of carbon dioxide that needs to be reduced / (ventilation fan unit time exhaust capacity × carbon dioxide concentration proportion of corresponding cross region), to achieve the exhaust of part of the carbon dioxide-rich air; if it is necessary to temporarily slow down the fruit respiration, calculate the temperature adjustment amplitude according to the correlation data of fruit respiration rate and temperature, temperature adjustment amplitude = (current fruit respiration rate - target respiration rate) / respiration temperature coefficient, wherein the target respiration rate = current carbon dioxide generation rate × preset coefficient, the adjusted temperature is maintained within the appropriate storage temperature range of the corresponding fruits, and the carbon dioxide generation rate is reduced by reducing the respiration rate.

[0109] Since the ventilation dead angle is easy to cause gas accumulation due to insufficient airflow, the ventilation strategy needs to be adjusted, and the specific adjustment process includes: extracting the airflow exchange rate corresponding to the cross region and the operating parameters of the ventilation fan, if the airflow exchange rate is lower than the preset airflow threshold, the working time of the ventilation fan is extended, the extension length=(preset airflow threshold-current airflow exchange rate) x ventilation time coefficient, or the ventilation fan speed is increased, the wind speed increase amplitude=(preset airflow threshold-current airflow exchange rate) / wind speed influence coefficient, and the gas circulation frequency is increased; if the hardware supports periodic change of wind direction, first obtain the forward and reverse control parameters of the ventilation fan and the distribution position of the cabin exhaust port, set the direction switching period, the switching period=the time required for the corresponding cross region gas to update x 2, in each period, first control the ventilation fan to rotate forward for a preset time, make the airflow flow to the corresponding cross region, then control the fan to reverse or open the corresponding exhaust port to exhaust for a preset time, make the accumulated gas in the corresponding cross region exhaust, and through periodic switching, fresh gas enters the original dead angle, and the gas flow state of the corresponding cross region is improved.

[0110] Finally, safety redundancy is introduced, and the specific method includes: based on the difference between the current oxygen concentration and the oxygen target concentration threshold, the difference between the current carbon dioxide concentration and the carbon dioxide target concentration threshold, and the proportion of the above difference to the corresponding target concentration threshold, the control algorithm can respond in advance, that is, corresponding adjustment is made before the sensor reaches the alarm threshold. For example, if the bottom oxygen is lower than the target value for a long time but not to the dangerous value, the oxygen is also actively increased slightly to prevent continuous decline from causing anaerobic respiration. In addition, if the ethylene concentration abnormally increases, corresponding measures are taken according to the set ethylene mild abnormal threshold and ethylene severe abnormal threshold, and the setting method of the ethylene mild abnormal threshold and the ethylene severe abnormal threshold is: extracting ethylene tolerance data of the target fruit variety, combining the storage period, setting the ethylene mild abnormal threshold to 1.5-2 times the ethylene release amount of the corresponding fruit in the early stage of maturity, and setting the ethylene severe abnormal threshold to 2.5-3 times the ethylene release amount of the corresponding fruit in the early stage of maturity; when the ethylene concentration is higher than the ethylene mild abnormal threshold and lower than or equal to the ethylene severe abnormal threshold, it is determined that there is a potential sign of deterioration, the ventilation module is started to strengthen the gas circulation in the cabin, the ventilation fan speed is increased to a preset strengthening gear, and the ethylene purification device operation power is increased, and the power increase amplitude = (current ethylene concentration-ethylene mild abnormal threshold) / ethylene concentration power coefficient, so as to reduce the ethylene concentration; when the ethylene concentration is higher than the ethylene severe abnormal threshold, it is determined that there is fruit deterioration, and the artificial inspection instruction is triggered at the same time as starting the ventilation module to strengthen the circulation and the ethylene purification device, and the instruction contains the position information of the corresponding abnormal area, that is, the corresponding cross area, prompting the operator to check the fruit state of the corresponding cross area, and removing the deteriorated fruit if necessary; at the same time, whether the ethylene concentration is in mild abnormality or severe abnormality, the oxygen content in the cabin needs to be increased to slightly higher than the oxygen target concentration threshold, and the increase amplitude = oxygen target concentration threshold x preset oxygen content increase coefficient, so as to quickly reverse the possible anaerobic state and inhibit further anaerobic respiration and rotting spread.

[0111] Embodiment 2:

[0112] Please refer to Figure 2 The embodiment provides a gas component control method for physical preservation, which comprises:

[0113] Collecting oxygen concentration data and carbon dioxide concentration data at different positions in the cabin, fruit respiration rate, stack structure and gap size data, ventilation air flow distribution data and ethylene concentration;

[0114] Determining the cross area based on the sampling points of the oxygen concentration data and the carbon dioxide concentration data at different positions in the cabin;

[0115] Determining whether the cross area is a ventilation dead angle based on the stack structure, the gap size data and the ventilation air flow distribution data;

[0116] Based on the current oxygen concentration, current carbon dioxide concentration, predicted concentration, and preset target gas concentration threshold of each intersection region, the intersection regions that have exceeded the safety threshold and are close to the critical point are identified.

[0117] Develop corresponding adjustment strategies based on the situation in each overlapping area.

[0118] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

[0119] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for controlling gas components in physical preservation, characterized in that, include: Data on oxygen and carbon dioxide concentrations, fruit respiration rates, stacking structure and gap dimensions, ventilation airflow distribution, and ethylene concentration were collected at different locations inside the cabin. Based on the sampling points of oxygen and carbon dioxide concentration data at different locations inside the cabin, the overlapping areas were determined; Based on the stacking structure, gap size data, and ventilation airflow distribution data, determine whether the intersection area is a ventilation dead zone; Based on the current oxygen concentration, current carbon dioxide concentration, predicted concentration, and preset target gas concentration threshold of each intersection region, the intersection regions that have exceeded the safety threshold and are close to the critical point are identified. Based on the situation in each cross-regional area, corresponding adjustment strategies will be formulated. Specifically, for cross-regional areas where oxygen concentrations are detected to exceed the safety threshold, appropriate measures will be taken to reduce the oxygen concentration, including: Extract the current oxygen concentration, oxygen safety lower limit threshold, oxygen target concentration threshold, and gas volume of the corresponding intersection region, and calculate the total oxygen concentration deviation of the corresponding intersection region; the gas volume is the spatial volume of the corresponding intersection region. Extract the oxygen consumption per unit time in the corresponding cross region, and calculate the oxygen flow rate that needs to be replenished per unit time by combining it with the preset oxygen replenishment buffer coefficient. The total amount of oxygen to be replenished is determined based on the oxygen flow rate required per unit time and the oxygen output of the gas mixing device. Determine the adjustment range of the oxygen valve opening based on the oxygen flow rate required per unit time; If the nitrogen injection rate needs to be adjusted simultaneously, calculate the reduction in nitrogen flow rate based on the mixing ratio of oxygen and nitrogen. Extract the airflow exchange rate and airflow diffusion coefficient of the corresponding cross area from the ventilation airflow distribution data; combine the spatial distance of the corresponding cross area and the preset airflow diffusion coefficient to calculate the theoretical time required for additional oxygen to diffuse to the corresponding cross area; the spatial distance of the corresponding cross area is the shortest path length from the air outlet of the gas mixing device to the corresponding cross area; Calculate the actual duration by combining the oxygen consumption per unit time in the corresponding cross-regions. The actual duration is not less than the theoretical duration.

2. The gas component control method for physical preservation according to claim 1, characterized in that, The methods for setting up sampling points for oxygen and carbon dioxide concentration data at different locations inside the cabin include: The vertical sampling layers are determined based on the overall height of the stack, dividing it into three sampling layers: top, middle, and bottom. The top sampling layer is set in the middle position between the top of the stack and the top of the storage compartment, the middle sampling layer is set at the center of the overall height of the stack, and the bottom sampling layer is set in the middle position between the bottom of the stack and the bottom of the storage compartment. The bottom sampling layer avoids the airflow obstruction area caused by the stack support structure. Determine the horizontal sampling area, using the ventilation opening as a reference, and divide it into three sampling areas: the area near the ventilation opening, the area away from the ventilation opening, and the center area of ​​the stack. The area near the ventilation opening is set within a certain distance directly in front of the ventilation opening, the area away from the ventilation opening is set at the farthest point from the ventilation opening inside the storage compartment, and the center area of ​​the stack is set at the geometric center of the horizontal distribution of the stack. A sampling point is set at the intersection of each sampling layer and each sampling area.

3. The gas component control method for physical preservation according to claim 2, characterized in that, Methods for determining the intersection region include: The intersection area is the location where the sampling layer and the sampling area meet; In the vertical direction, the height range of each intersection area corresponds to the height range of the vertical sampling layer to which it belongs. The height range of the top intersection area is the space between the top of the stack and the top of the storage compartment. The height range of the middle intersection area is the middle range of the overall height of the stack. The height range of the bottom intersection area is the space between the bottom of the stack and the bottom of the storage compartment. The height boundary of each vertical section is based on the layer boundary of the adjacent stacking unit in the stacking structure. In the horizontal direction, the planar range of each intersection area corresponds to the planar interval of the horizontal sampling area. The planar range of the intersection area near the vent is the stacked horizontal area that can be covered by the vent outlet. The planar range of the intersection area in the center of the stack is the planar area around the geometric center of the horizontal distribution of the stack, covering at least one complete stacking unit. The planar range of the intersection area far from the vent is the stacked horizontal area in the storage compartment that is farthest from the vent and does not overlap with the stack edge. The length and width boundaries of each horizontal interval are based on the arrangement spacing of the stacking units. The intersection area is the three-dimensional spatial region enclosed by the height range and the plane range.

4. The gas composition control method for physical preservation according to claim 1, characterized in that, Methods for determining intersection regions that have exceeded safety thresholds or are close to critical include: The target gas concentration thresholds include the lower safe limit threshold for oxygen, the upper safe limit threshold for carbon dioxide, the range of oxygen near the critical threshold, and the range of carbon dioxide near the critical threshold. When there is an intersection where the current oxygen concentration is lower than the lower safety limit threshold or the current carbon dioxide concentration is higher than the upper safety limit threshold, the corresponding intersection is determined to be an intersection that exceeds the safety threshold. When there is an intersection where the current oxygen concentration is close to the critical threshold or the current carbon dioxide concentration is close to the critical threshold, the corresponding intersection is determined to be the current critical intersection. When there is a cross-region where the predicted concentration is lower than the oxygen safety lower limit threshold or higher than the carbon dioxide safety upper limit threshold within a preset time period in the future, the corresponding cross-region is determined to be a cross-region that will exceed the safety threshold in the future. When there is a cross-region where the predicted concentrations will enter the critical threshold range for oxygen or carbon dioxide within a preset time period in the future, the corresponding cross-region is determined to be a cross-region that will approach the critical threshold in the future. Cross regions that have exceeded the safety threshold include cross regions that currently exceed the safety threshold and cross regions that will exceed the safety threshold in the future. Cross regions that are close to the critical threshold include cross regions that are currently close to the critical threshold and cross regions that will be close to the critical threshold in the future.

5. The gas component control method for physical preservation according to claim 4, characterized in that, Methods for obtaining predicted concentrations include: The predicted concentrations include predicted oxygen and carbon dioxide concentrations; Substitute the input parameters of each intersection region into the preset concentration change formula to calculate the predicted concentration after the future time step; The input parameters for each cross zone include the current oxygen concentration, current carbon dioxide concentration, oxygen consumption per unit time, carbon dioxide production per unit time, and airflow exchange rate of each cross zone extracted from ventilation airflow distribution data.

6. The gas composition control method for physical preservation according to claim 5, characterized in that, Methods for obtaining oxygen consumption per unit time and carbon dioxide production per unit time include: The oxygen consumption rate and carbon dioxide release rate per unit mass of fruit per unit time are extracted from the fruit respiration rate at the current temperature, current oxygen concentration, and current carbon dioxide concentration. Multiply the stack volume corresponding to each intersection area by the fruit stack density to obtain the total mass of the fruit in each intersection area; Multiply the oxygen consumption rate per unit mass of fruit per unit time by the total mass of fruit in each cross region to obtain the oxygen consumption per unit time in each cross region. Multiply the carbon dioxide release rate per unit mass of fruit per unit time by the total mass of fruit in each cross region to obtain the carbon dioxide production per unit time in each cross region.

7. The gas component control method for physical preservation according to claim 1, characterized in that, Methods for determining whether an intersection area is a ventilation dead zone include: Extract the stacking gap size and stacking layer number corresponding to each intersection area from the stacking structure and gap size data; Set critical values ​​for stacking gap and stacking layer number; When the stacking gap size of the intersecting area is less than the critical value of the stacking gap, or the number of stacking layers is greater than the critical value of the number of stacking layers, or the intersecting area overlaps with the position of the stacking support structure, the corresponding intersecting area is determined to be an airflow obstruction area. When the airflow velocity value in the obstructed area is less than the set airflow velocity threshold, the corresponding obstructed area is determined to be a ventilation dead zone; the airflow velocity value in the obstructed area is obtained through ventilation airflow distribution data.

8. The gas component control method for physical preservation according to claim 1, characterized in that, Methods for developing corresponding adjustment strategies based on the situation in each overlapping area include: For near-critical cross-regions, oxygen flow is supplemented, fan speed is increased, or the low-power operation mode of the carbon dioxide removal device is activated according to the preset adjustment method. For cross-regional areas where carbon dioxide concentration exceeds the safety threshold, appropriate measures should be taken to reduce the carbon dioxide concentration. For ventilation dead zones, adjust the ventilation strategy according to the preset method.

9. A method for controlling gas components for physical preservation according to claim 8, characterized in that, For cross-regional areas where carbon dioxide concentrations exceed safe thresholds, appropriate measures to reduce carbon dioxide concentrations include: Based on the current carbon dioxide concentration, the upper limit threshold of carbon dioxide safety, and the gas volume of the corresponding cross region, the total amount of carbon dioxide that needs to be reduced in the cross region where the carbon dioxide concentration exceeds the safety threshold is calculated. If a carbon dioxide removal device is installed, the operating parameters of the device should be adjusted according to the processing capacity per unit time of the carbon dioxide removal device until the required amount of carbon dioxide is reduced. If a carbon dioxide removal device is not equipped, when using a short-term method to reduce the cabin pressure, the pressure reduction range is calculated based on the total amount of carbon dioxide to be reduced and the initial cabin pressure obtained in advance; when using a directional ventilation method, the ventilation openings in the corresponding directions are opened according to the location of the corresponding intersection area, and the ventilation fan speed is adjusted to the preset high speed level.

10. A gas component control system for physical preservation, used to implement the gas component control method for physical preservation according to any one of claims 1-9, characterized in that, include: The data acquisition module is used to collect oxygen and carbon dioxide concentration data, fruit respiration rate, stacking structure and gap size data, ventilation airflow distribution data, and ethylene concentration at different locations inside the cabin. The area division module determines overlapping areas based on sampling points of oxygen and carbon dioxide concentration data at different locations within the cabin. The first determination module determines whether the intersection area is a ventilation dead zone based on the stacking structure, gap size data, and ventilation airflow distribution data. The second determination module, based on the current oxygen concentration, current carbon dioxide concentration, predicted concentration and preset target gas concentration threshold of each intersection region, determines the intersection regions that have exceeded the safety threshold and are close to the critical point. The strategy formulation module is used to formulate corresponding adjustment strategies based on the situation in each cross-region.

Images