Outer package monitoring method for frozen chicken product

Abstract

The invention relates to the technical field of chicken product outer package monitoring, in particular to an outer package monitoring method for frozen chicken products, which comprises the following steps: putting a packaging bag filled with frozen chicken products into a vacuum sealing tank; adjusting the interval duration between the starting moment of air exhaust of the vacuum pump and the moment of putting the packaging bag into the vacuum sealing tank; actual air exhaust is carried out; determining the bubble damage degree in the clear water, and calculating a second dissolved amount according to the gas reduction rate; the second contraction speed of the packaging bag is obtained again, and the first dissolved amount of gas in the packaging bag in the actual gas extraction process is calculated according to the second contraction speed; determining the overall dissolved amount of leaked gas in clear water; determining the rotating speed of the vacuum pump; determining the bubble precipitation amount in the clear water; adjusting the height difference between the clear water level and the packaging bag; determining the bubble amount after correction; and determining whether the outer package sealing performance of the frozen chicken product is qualified. According to the invention, the accuracy and reliability of the air tightness detection of the outer package of the frozen chicken product are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of chicken product outer packaging monitoring, and particularly relates to a method for monitoring the outer packaging of frozen chicken products. BACKGROUND

[0002] In the prior art, the negative pressure method is usually used to detect the air tightness of the outer packaging of chicken products, and the number of bubbles is simply observed and calculated, but the gas escaping from the leakage point is partially dissolved in water during the rising process, resulting in that the actual observed number of bubbles is less than the number of bubbles generated by the real leakage, causing missed detection; in the vacuum environment, factors such as shrinkage of the packaging bag and change of water temperature may cause the dissolved gas in water to be precipitated to form false bubbles, and the false bubbles are not from the packaging leakage, causing false positives; the prior art usually uses fixed vacuum pumping rate and starting time. However, for packaging bags of different sizes, different initial packaging pressures and different leakage rates, the shrinkage speed and internal gas release law are different, and the fixed parameters cannot optimize the detection process, resulting in that the early leakage dissolution is covered up or too many bubbles are precipitated in the clean water to be unable to be counted, causing inaccurate detection results, and finally causing large monitoring fluctuation range and high error rate, thereby causing misjudgment of the air tightness of the outer packaging of frozen chicken products and reducing the product qualification rate.

[0003] Chinese Patent Publication No. CN116735096A discloses a gas tightness detection device and detection method, which comprises a liquid storage box filled with liquid, a gas collection device including a gas collection cover, a gas collection pipe, a gas detector and a gas extraction device, the gas collection pipe sequentially connects the gas collection cover, the gas detector and the gas extraction device, and the gas collection end of the gas collection cover is located in the liquid of the liquid storage box, and a bubble detachment device is arranged on the side wall of the liquid storage box. As can be seen, the gas tightness detection device and detection method can monitor the packaging method of rice freshness, and the bubble quantity monitoring result is less than the real bubble quantity due to the phenomena of early leakage dissolution of bubbles and bubble damage, the gas precipitated in the clean water is also counted in the monitoring result, resulting in that the bubble quantity monitoring result is greater than the real bubble quantity, and further causing high monitoring error rate, and finally causing misjudgment of the outer packaging air tightness and low product qualification rate. SUMMARY

[0004] Therefore, the present application provides a method for monitoring the outer packaging of frozen chicken products to overcome the problems in the prior art that the bubble quantity monitoring result is less than the real bubble quantity due to the phenomena of early leakage dissolution of bubbles and bubble damage, the gas precipitated in the clean water is also counted in the monitoring result, resulting in that the bubble quantity monitoring result is greater than the real bubble quantity, further causing high monitoring error rate, and finally causing misjudgment of the air tightness of the outer packaging of frozen chicken products and low product qualification rate.

[0005] To achieve the above object, the application provides a method for monitoring the outer package of frozen chicken products, comprising: putting the package bag containing the frozen chicken products into a vacuum sealed tank containing clean water, and controlling the vacuum pump to perform a test of air extraction from the vacuum sealed tank; obtaining the first shrinkage speed of the package bag; adjusting the interval time length between the starting time of air extraction by the vacuum pump and the time when the package bag is put into the vacuum sealed tank according to the first shrinkage speed of the package bag; controlling the vacuum pump to perform actual air extraction from the vacuum sealed tank according to the interval time length; respectively collecting the air inlet temperature of the air inlet of the air extraction pipeline, the filter temperature of the inlet filter and the air pressure reduction rate in the vacuum sealed tank after the actual air extraction; determining the bubble breaking degree in the clean water according to the air inlet temperature, the filter temperature and the air pressure reduction rate, and calculating the second dissolved amount according to the air reduction rate; re-obtaining the second shrinkage speed of the package bag, and calculating the first dissolved amount of the gas in the package bag during the actual air extraction process according to the second shrinkage speed; determining the overall dissolved amount of the leaked gas in the package bag in the clean water according to the first dissolved amount and the second dissolved amount; determining the rotating speed of the vacuum pump according to the overall dissolved amount; obtaining the stirring amplitude of the clean water and the temperature change amount of the clean water during the vacuum extraction process according to the rotating speed of the vacuum pump; determining the bubble precipitation amount in the clean water according to the stirring amplitude of the clean water and the temperature change amount of the clean water; adjusting the height difference between the liquid surface of the clean water and the package bag according to the bubble precipitation amount; obtaining the monitored bubble amount, and determining the corrected bubble amount according to the overall dissolved amount, the bubble precipitation amount and the monitored bubble amount; determining whether the outer package sealing performance of the frozen chicken products is qualified according to the corrected bubble amount.

[0006] Further, the gas early leakage dissolved coefficient is the product of the shrinkage speed of the package bag and a preset conversion coefficient.

[0007] Further, the interval time length is positively correlated with the gas early leakage dissolved coefficient.

[0008] Further, determining the bubble breaking degree in the clean water according to the air inlet temperature, the filter temperature and the air pressure reduction rate comprises: calculating the temperature difference amount between the air inlet of the air extraction pipeline and the inlet filter according to the air inlet temperature of the air inlet and the filter temperature of the inlet filter; Compare the temperature difference with a preset temperature difference; The rate of decrease in air pressure inside the vacuum-sealed container is compared with the preset rate of decrease in air pressure. If the temperature difference is greater than the preset temperature difference, and the rate of decrease in air pressure inside the vacuum-sealed container is less than the preset rate of decrease in air pressure, then it is determined that the degree of bubble destruction in the water exceeds the allowable range.

[0009] Furthermore, the total amount of dissolution is the sum of the first amount of dissolution and the second amount of dissolution.

[0010] Furthermore, the power of the vacuum pump is negatively correlated with the overall amount of gas leaked from the packaging bag dissolved in clean water.

[0011] Further, the amount of air bubbles precipitated in the clear water is determined, including: The time it takes for the packaging bag to retract and generate agitation is obtained; The change in temperature during the time the packaging bag retracts and agitates is obtained; The amount of bubbles produced is determined based on the temperature change.

[0012] Furthermore, when the amount of bubbles released is greater than the preset amount, the height difference between the water surface and the packaging bag is increased.

[0013] Furthermore, the height difference between the water surface and the packaging bag is directly proportional to the amount of bubbles released.

[0014] Furthermore, the corrected bubble quantity is the sum of the difference between the monitored bubble quantity and the amount of bubble precipitation and the amount dissolved in the water.

[0015] Compared with existing technologies, the beneficial effect of this invention lies in reducing the problem of inaccurate test results and misjudgments of the airtightness of frozen chicken product packaging by monitoring the solubility coefficient of gas leaking prematurely in the packaging bag. This is because the low temperature of frozen chicken products lowers the temperature of the water in the vacuum-sealed container, increasing the solubility of gas in the water. As the gas in the packaging bag rises to the liquid surface, it is absorbed and dissolved by the water, resulting in a lower monitored bubble quantity than the total gas volume in the packaging bag. This leads to inaccurate test results and misjudgments of the packaging bag's airtightness. The invention effectively detects the premature leakage and dissolution of gas in the packaging bag. Monitoring, identification, and early warning of air bubbles; by starting the vacuum pump earlier, the cooling effect of frozen chicken products on water is reduced, weakening the influence of temperature on the solubility of gases in water, and shortening the time window for premature gas leakage and dissolution in the packaging bag. This ultimately reduces the impact of premature gas leakage and dissolution on the test results, improving their accuracy. Furthermore, by monitoring the degree of bubble destruction in the water, the temperature at the air inlet of the extraction pipe, caused by the heat generated by the vacuum pump during the airtightness test of the frozen chicken product packaging, is reduced to a lower temperature than the filtration temperature of the vacuum pump's inlet filter, thus preventing premature leakage and dissolution. Increased pressure in the extraction pipe near the inlet filter of the vacuum pump leads to a slower rate of pressure reduction within the vacuum sealing tank. This allows more time for the gas in the packaging bag to dissolve in the water, resulting in a lower test result than the actual amount of gas in the bag and causing misjudgments of the bag's airtightness. This method enables the monitoring, identification, and quantitative early warning of bubble breakage. By monitoring the time and temperature changes of the water agitated by the bag's retraction, the amount of bubble formation is determined, reducing the risk of bag retraction during the airtightness testing of frozen chicken product packaging due to continuous gas release. The phenomenon of bubble release is observed in the packaging bag. The shrinkage of the packaging bag causes agitation of the water, which in turn raises the temperature of the agitated area. As the temperature rises, the solubility of gases in the water gradually decreases, causing dissolved gases to be released. Some of these gases are reabsorbed and dissolved by other areas of water as they rise, while others float to the surface. The amount of these bubbles is then counted in the gas volume within the packaging bag. This method enables timely monitoring and early warning of bubble release, reduces the impact of bubble release on the test results, improves the accuracy of airtightness testing of frozen chicken packaging, reduces misjudgments of airtightness, and increases the product qualification rate.

[0016] Furthermore, by acquiring the shrinkage rate, a directly measurable physical quantity, and combining it with a preset conversion coefficient, the present invention converts the implicit gas leakage dissolution coefficient into a specific value, thereby reducing the impact of gas leakage dissolution on the airtightness test results of the outer packaging of frozen chicken products, improving the accuracy of the test, reducing misjudgments of the airtightness of the outer packaging, and improving the product qualification rate.

[0017] Furthermore, if only the temperature difference is used as the criterion, normal heat dissipation of the equipment may be misjudged as bubble breakage; if only the rate of pressure reduction is lower than a preset value is used as the criterion, non-bubble breakage factors such as vacuum pump power fluctuations and minor pipeline blockages may be misjudged as bubble breakage. This invention sets preset temperature difference and preset pressure reduction rate. When both the temperature difference is greater than the preset temperature difference and the rate of pressure reduction in the vacuum sealing tank is less than the preset rate of pressure reduction, the degree of bubble breakage is determined to exceed the allowable range. This eliminates the interference of a single factor, avoids misjudgments of bubble breakage due to environmental fluctuations, and ensures the accuracy of the judgment results.

[0018] Furthermore, when the amount of air bubbles dissolving in water from the packaging bag exceeds the allowable range, indicating premature gas leakage or severe bubble destruction, reducing the vacuum pump speed slows the rate of pressure drop within the vacuum-sealed container. This reduces the shrinkage rate of the packaging bag, thereby decreasing the rate of gas leakage from the leak point. Because the gas leakage rate is slower, the residence time of the gas in the water is shortened, reducing the chance of the gas dissolving in the water. According to Henry's Law, gas solubility is positively correlated with pressure; the slower the pressure drop, the less gas is dissolved. Therefore, reducing the speed inhibits premature gas leakage and dissolution. When the vacuum pump operates at high speed, the heat generated causes a temperature difference between the air inlet of the extraction pipe and the inlet filter. The greater the temperature difference, the greater the degree of bubble destruction. Reducing the vacuum pump speed reduces heat generation, thereby reducing the temperature difference and weakening the degree of bubble destruction. This makes the bubbles more stable during their ascent, less prone to destruction and dissolution, resulting in a more accurate detection of the amount of leaked bubbles compared to the actual amount.

[0019] Furthermore, by measuring the water temperature change during the agitation period, the amount of air released due to temperature fluctuations can be calculated, clearly distinguishing between false air bubbles and genuine air bubbles from packaging leaks. This enables the monitoring and identification of air bubble release, improving detection accuracy, reducing misjudgments of the airtightness of outer packaging, and increasing product qualification rates.

[0020] Furthermore, as the pressure decreases, the packaging bag retracts, exerting an instantaneous inward squeezing force—agitation—on the surrounding water, causing displacement and turbulence. When the water layer above the packaging bag is thicker, the total mass and inertia of this water volume are also greater. According to Newton's First Law, the greater the mass of an object, the more difficult it is to change its state of motion. Therefore, when the packaging bag attempts to agitate the water, the thicker and heavier water above it resists this sudden movement, reducing the amplitude of the packaging bag's agitation. This reduces the temperature change in the surrounding water, decreases the amount of bubbles produced, and thus reduces the impact of bubble production on the test results, improving the accuracy of the test, reducing misjudgments of the airtightness of the outer packaging, and increasing the product qualification rate. Attached Figure Description

[0021] Figure 1 This is a flowchart of a method for monitoring the outer packaging of frozen chicken products according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the detection equipment structure for the monitoring method of the outer packaging of frozen chicken products according to an embodiment of the present invention; Figure 3 This is a flowchart illustrating the method for monitoring the outer packaging of frozen chicken products according to an embodiment of the present invention, which determines the amount of bubbles produced based on the time and temperature change of water agitated due to the retraction of the packaging bag. Figure 4 This is a structural block diagram of the detection equipment used in the monitoring method for the outer packaging of frozen chicken products according to an embodiment of the present invention; Attached diagram: 1-Vacuum sealed container, 2-Water inlet valve, 3-Frozen chicken products and outer packaging, 4-Water outlet valve, 5-Air extraction pipe, 6-Vacuum pump. Detailed Implementation

[0022] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0023] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0024] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0025] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0026] Please see Figure 1 , Figure 2 , Figure 3 as well as Figure 4The diagram shows a flowchart of a method for monitoring the outer packaging of frozen chicken products according to an embodiment of the present invention, a schematic diagram of the detection equipment, a flowchart for determining the amount of bubbles produced based on the time and temperature change of water due to the retraction of the packaging bag, and a block diagram of the detection equipment. The method for monitoring the outer packaging of frozen chicken products according to the present invention includes: Step S1: Place the packaging bag containing frozen chicken products into a vacuum-sealed container filled with clean water, and control the vacuum pump to perform an air extraction test from the vacuum-sealed container. In practice, a packaging bag sealing tester is used. The packaging bag containing frozen chicken products is placed inside the vacuum sealing chamber 1 of the tester. The vacuum pump 6 is then activated to extract air. The vacuum pump 6 continuously extracts air from the vacuum sealing chamber 1 through the extraction pipe 5, causing the air pressure inside the chamber, i.e., the external pressure of the packaging bag, to drop rapidly. According to the testing requirements, the final air pressure inside the chamber drops to 0.02–0.08 MPa, which is far lower than the initial standard atmospheric pressure inside the packaging bag, forming a stable pressure difference between the outside and the inside.

[0027] Specifically, distilled water should be used, with a temperature of 15–25°C. The water level should be 5–10 cm above the highest point of the packaging bag to ensure complete immersion. The initial evacuation rate should be controlled at 1–3 m³ / h, adjusted according to the volume of the vacuum sealing tank. Once the pressure inside the tank drops to the target value of 0.02–0.08 MPa, this pressure should be maintained for 1–2 minutes before observing bubbles. Preferably, distilled water should be used at 20°C, with the water level 10 cm above the highest point of the packaging bag to ensure complete immersion. The initial evacuation rate should be controlled at 2 m³ / h. Once the pressure inside the tank drops to the target value of 0.05 MPa, this pressure should be maintained for 1 minute.

[0028] Step S2: Obtain the first shrinkage speed of the packaging bag; Specifically, the length or width of the packaging bag is preferred as the monitoring dimension because frozen chicken products are mostly of regular and uniform shape, making it easier to accurately measure changes in length or width, and these changes are linearly correlated with changes in the amount of gas inside the bag. A laser displacement sensor with an accuracy of 0.01 mm is used to obtain the amount of shrinkage in the length or width of the packaging bag, and the shrinkage speed is obtained based on the amount of shrinkage and the shrinkage time.

[0029] Step S3: Adjust the interval between the start time of the vacuum pump and the time when the packaging bag is placed into the vacuum sealing container according to the first shrinkage speed of the packaging bag.

[0030] Specifically, the gas leakage solubility coefficient is the product of the shrinkage rate of the packaging bag and the preset conversion coefficient.

[0031] Specifically, the preset conversion coefficient is a proportional constant, which is used to convert the shrinkage rate of the packaging bag into the gas premature leakage dissolution coefficient; Optionally, the preset conversion coefficient can be implemented in the range of [0.4 ml / (mm·s), 0.6 ml / (mm·s)], and preferably, the preferred embodiment of the preset conversion coefficient is 0.5 ml / (mm·s).

[0032] Specifically, this invention obtains the shrinkage rate, a directly measurable physical quantity, and then combines it with a preset conversion coefficient to convert the implicit gas leakage dissolution coefficient into a specific value. This reduces the impact of gas leakage dissolution on the airtightness test results of the outer packaging of frozen chicken products, improves the accuracy of the test, reduces misjudgments of the airtightness of the outer packaging, and improves the product qualification rate.

[0033] Step S4: Control the vacuum pump to actually evacuate air from the vacuum sealed container according to the specified interval; Specifically, the interval duration is positively correlated with the gas premature leakage solubility coefficient.

[0034] Specifically, when the gas leakage solubility coefficient is within 0.05 ml, the vacuum pump start time is advanced by 1 second. When the gas leakage solubility coefficient exceeds 0.05 ml, the vacuum pump start time is advanced by 0.1 seconds for every 0.01 ml exceeding 0.05 ml. In a specific embodiment, the gas leakage solubility coefficient is 0.08 ml, so the vacuum pump start time is advanced by 1 second + (0.08 ml - 0.05 ml) ÷ 0.01 ml × 0.1 s = 1.3 s.

[0035] Step S5: Control the vacuum pump to actually evacuate air from the vacuum sealed container according to the specified interval; Step S6: Collect the inlet temperature of the actual evacuation pipe, the filtration temperature of the inlet filter, and the rate of decrease in air pressure inside the vacuum sealing tank. In implementation, a platinum resistance temperature sensor with an accuracy of ±0.1℃ is used to obtain the temperature of the air inlet of the extraction pipe and the temperature of the inlet filter; a pressure sensor with a measurement range of 0~0.1MPa and an accuracy of ±0.001MPa is installed on the top of the vacuum sealing tank 1 to obtain the air pressure of the vacuum sealing tank 1. The rate of decrease of air pressure is obtained by continuously monitoring the air pressure and calculating the differential value.

[0036] Step S7: Determine the degree of bubble destruction in the water based on the inlet air temperature, the filtration temperature, and the rate of decrease in air pressure, and calculate the second amount of dissolved gas based on the rate of decrease in air pressure, including: The temperature difference between the air inlet of the extraction pipe and the inlet filter is calculated based on the air inlet temperature and the filtration temperature of the inlet filter. Compare the temperature difference with a preset temperature difference; The rate of decrease in air pressure inside the vacuum-sealed container is compared with the preset rate of decrease in air pressure. If the temperature difference is greater than the preset temperature difference, and the rate of decrease in air pressure inside the vacuum-sealed container is less than the preset rate of decrease in air pressure, then it is determined that the degree of bubble destruction in the water exceeds the allowable range.

[0037] Optionally, the preset temperature difference can be implemented within a range of [0.5℃, 0.7℃], with a preferred embodiment of 0.6℃.

[0038] Optionally, the preset pressure reduction rate can be implemented in the range of [0.60 kPa / s, 0.82 kPa / s], and the preferred embodiment of the preset pressure reduction rate is 0.71 kPa / s.

[0039] Specifically, if only the temperature difference is used as the criterion, normal heat dissipation of the equipment may be misjudged as bubble breakage; if only the rate of pressure reduction is lower than a preset value is used as the criterion, non-bubble breakage factors such as vacuum pump power fluctuations and minor pipeline blockages may be misjudged as bubble breakage. This invention sets preset temperature difference and preset pressure reduction rate. When both the temperature difference is greater than the preset temperature difference and the rate of pressure reduction in the vacuum sealing tank is less than the preset rate of pressure reduction, the degree of bubble breakage is determined to exceed the allowable range. This eliminates the interference of a single factor, avoids misjudgments of bubble breakage due to environmental fluctuations, and ensures the accuracy of the judgment results.

[0040] Step S8: Reacquire the second shrinkage speed of the packaging bag, and calculate the first amount of gas dissolved in the packaging bag during the actual evacuation process based on the second shrinkage speed.

[0041] Specifically, the power of the vacuum pump is negatively correlated with the overall amount of gas leaked from the packaging bag dissolved in clean water.

[0042] Step S9: Determine the total amount of gas leaked from the packaging bag in clean water based on the first amount of dissolution and the second amount of dissolution.

[0043] Specifically, the total amount of dissolution is the sum of the first amount of dissolution and the second amount of dissolution.

[0044] Specifically, the first dissolution amount = the second contraction rate × the actual pumping time; Second dissolution amount = gas reduction rate × vacuum pump operating time.

[0045] Specifically, the amount of gas dissolved in water by the bubbles expelled from the packaging bag is the total amount of gas dissolved by the premature leakage and the amount of gas dissolved by the bubble destruction. It reflects the amount of gas in the packaging bag that cannot be monitored due to premature leakage and bubble destruction.

[0046] Specifically, when the amount of air bubbles discharged from the packaging bag that dissolves in water is less than 0.1 ml, the pumping power of the vacuum pump is reduced by 0.1 cm³ / s. When the amount of air bubbles discharged from the packaging bag that dissolves in water exceeds 0.1 ml, the pumping power of the vacuum pump is reduced by 0.01 cm³ / s for every 0.01 ml exceeding the limit. In a specific embodiment, the amount of air bubbles discharged from the packaging bag that dissolves in water is 0.15 ml. The current pumping power of the vacuum pump 6 is 2 m³ / h, which is 556 cm³ / s. Therefore, the reduced pumping power of the vacuum pump 6 is 556 cm³ / s - 0.1 cm³ / s - (0.15 ml - 0.1 ml) ÷ 0.01 ml × 0.01 cm³ / s = 555.85 cm³ / s.

[0047] Specifically, when the amount of air bubbles dissolving in water from the packaging bag exceeds the allowable range, indicating premature gas leakage or severe bubble destruction, reducing the vacuum pump speed slows the rate of pressure drop within the vacuum-sealed container. This reduces the shrinkage rate of the packaging bag, thus decreasing the rate of gas leakage from the leak point. Because the gas leakage rate is slower, the residence time of the gas in the water is shortened, reducing the chance of gas dissolving in the water. According to Henry's Law, gas solubility is positively correlated with pressure; the slower the pressure drop, the less gas is dissolved. Therefore, reducing the speed suppresses premature gas leakage and dissolution. When the vacuum pump operates at high speed, the heat generated causes a temperature difference between the air inlet of the extraction pipe and the inlet filter. The greater the temperature difference, the greater the degree of bubble destruction. Reducing the vacuum pump speed reduces heat generation, thereby reducing the temperature difference and weakening the degree of bubble destruction. This makes the bubbles more stable during their ascent, less prone to destruction and dissolution, resulting in a more accurate detection of the amount of leaked bubbles compared to the actual amount.

[0048] Step S9: Determine the rotational speed of the vacuum pump based on the total amount dissolved; Step S10: Obtain the agitation amplitude and temperature change of the water during the vacuuming process according to the rotation speed of the vacuum pump. Step S11: Determine the amount of bubbles released in the water based on the agitation amplitude and temperature change of the water.

[0049] Specifically, determining the amount of air bubbles released into the water includes: The time it takes for the packaging bag to retract and generate agitation is obtained; The change in temperature during the time the packaging bag retracts and agitates is obtained; The amount of bubbles produced is determined based on the temperature change.

[0050] Specifically, the vibration amplitude of the tank is equivalent to the agitation amplitude of clear water.

[0051] In practice, pressure and accelerometer sensors are used. The pressure sensor monitors the period from when the pressure inside the vacuum tank begins to drop significantly, indicating the start of vacuuming, to when the pressure stabilizes, indicating that the packaging bag shrinkage is essentially complete. The accelerometer monitors the vibration amplitude of the tank during the period when the packaging bag retracts and causes agitation. A platinum resistance temperature sensor is used to obtain the temperature change during this period.

[0052] Specifically, the amount of gas produced is the product of the calibration coefficient and the temperature change during the time the packaging bag retracts and agitates; whereby the calibration coefficient represents the volume of gas produced by the water under a unit temperature change, and the value of the calibration coefficient is 0.26 ml / ℃.

[0053] It is understandable that the calibration coefficients are conventional physical properties well known to those skilled in the art, and the acquisition of the calibration coefficients will not be elaborated here.

[0054] Specifically, by measuring the water temperature change during the agitation period, the amount of air released due to temperature fluctuations can be calculated, clearly distinguishing between false air bubbles and genuine air bubbles from packaging leaks. This enables the monitoring and identification of air bubble release, improving detection accuracy, reducing misjudgments of the airtightness of outer packaging, and increasing product qualification rates.

[0055] Step S12: Adjust the height difference between the water level and the packaging bag according to the amount of bubbles produced; Specifically, when the amount of bubbles released exceeds the preset amount, the height difference between the water surface and the packaging bag is increased.

[0056] Specifically, the height difference between the water surface and the packaging bag is directly proportional to the amount of air bubbles produced.

[0057] Specifically, the height difference increases the vertical distance between the surface of the clear water and the packaging bag.

[0058] Optionally, with a water volume of 2L in the vacuum-sealed container, the preset precipitation amount can be selected within the range of [0.03ml, 0.05ml], and the preferred embodiment of the preset precipitation amount is 0.04ml.

[0059] During implementation, when the amount of bubble precipitation exceeds the preset amount, it is determined that the generation of false bubbles interferes with the monitoring. In this case, the water inlet valve 2 is opened to increase the height difference between the clear water surface and the packaging bag.

[0060] Specifically, when the difference between the amount of bubbles released and the preset amount of bubbles is within 0.02 ml, the height difference between the water surface and the packaging bag is increased by 0.1 cm. When the difference between the amount of bubbles released and the preset amount of bubbles exceeds 0.02 ml, the height difference between the water surface and the packaging bag is increased by 0.01 cm for every 0.01 ml exceeding the preset amount of bubbles. In a specific embodiment, the amount of bubbles released is 0.08 ml, the preset amount of bubbles is 0.04 ml, and the current height difference between the water surface and the packaging bag is 20 cm. Then, the increased height difference between the water surface and the packaging bag is 20 cm + 0.1 cm + (0.08 ml - 0.04 ml - 0.02 ml) ÷ 0.01 ml × 0.01 cm = 20.12 cm.

[0061] Specifically, the packaging bag retracts under reduced pressure, and this action exerts an instantaneous inward squeezing force, i.e., agitation, on the surrounding water, causing displacement and turbulence. When the water layer above the packaging bag is thicker, the total mass and inertia of this water volume are also greater. According to Newton's First Law, the greater the mass of an object, the more difficult it is to change its state of motion. Therefore, when the packaging bag attempts to agitate the water, the thicker and heavier water above it resists this sudden movement, reducing the amplitude of the packaging bag's agitation. This reduces the temperature change of the surrounding water, decreases the amount of bubbles produced, and thus reduces the impact of bubble production on the test results, improves the accuracy of the test, reduces misjudgments of the airtightness of the outer packaging, and increases the product qualification rate.

[0062] Step S13: Obtain the monitored bubble quantity, and determine the corrected bubble quantity based on the total dissolved amount, the bubble precipitation amount, and the monitored bubble quantity.

[0063] Specifically, the amount of bubbles monitored is obtained through an optical bubble sensor.

[0064] Specifically, the corrected bubble quantity is the sum of the difference between the monitored bubble quantity and the amount of bubble precipitation, and the amount dissolved in the water.

[0065] Specifically, the corrected bubble volume is the total amount of gas present inside the outer packaging of frozen chicken products.

[0066] Specifically, by monitoring the solubility coefficient of gas leaking prematurely in the packaging bag, the problem of inaccurate test results and misjudgments of the airtightness of frozen chicken product packaging is reduced. This is because the low temperature of frozen chicken products lowers the temperature of the water in the vacuum sealing tank, increasing the solubility of gas in the water. As the gas rises to the liquid surface, it is absorbed and dissolved by the water, resulting in a lower monitored bubble quantity than the total gas volume in the packaging bag. This leads to inaccurate test results and misjudgments of the packaging bag's airtightness. This method enables the monitoring, identification, and early warning of premature gas leakage and dissolution in the packaging bag. Furthermore, by starting the vacuum pump earlier, the cooling effect of the frozen chicken products on the water is reduced, weakening the influence of temperature on the gas solubility in the water and shortening the time window for premature gas leakage and dissolution in the packaging bag. This ultimately reduces the impact of premature gas leakage and dissolution on the test results and improves their accuracy. Finally, by monitoring the degree of bubble destruction in the water, the problem of the temperature at the air inlet of the suction pipe being lower than the filtration temperature of the inlet filter of the vacuum pump 6 due to the heat generated by the suction pump during the airtightness test of the frozen chicken product packaging is reduced. This prevents the gas from near the vacuum pump 6 from being absorbed and dissolved. Increased pressure in the extraction pipe on the inlet filter side leads to a slower rate of pressure reduction within the vacuum sealing tank. This allows more time for the gas in the packaging bag to dissolve in the water, resulting in a lower test result than the actual amount of gas in the bag and causing misjudgments of the bag's airtightness. This method enables the monitoring, identification, and quantitative early warning of bubble breakage. By monitoring the time and temperature changes of the water agitated by the bag's retraction, the amount of bubble formation is determined, reducing the risk of bag retraction during the airtightness testing of frozen chicken product packaging due to continuous gas release. The phenomenon of bubble release is observed in the packaging bag. The shrinkage of the packaging bag causes agitation of the water, which in turn raises the temperature of the agitated area. As the temperature rises, the solubility of gases in the water gradually decreases, causing dissolved gases to be released. Some of these gases are reabsorbed and dissolved by other areas of water as they float to the surface, and the rest float to the surface. The amount of bubbles detected is included in the gas volume count inside the packaging bag. This method enables timely monitoring of bubble release, reduces the impact of bubble release on the test results, improves the accuracy of airtightness testing of frozen chicken packaging, reduces misjudgments of airtightness, and increases the product qualification rate.

[0067] Step S14: Determine whether the sealing performance of the outer packaging of frozen chicken products is qualified based on the corrected bubble amount.

[0068] Specifically, the greater the amount of bubbles after correction, the weaker the airtightness of the outer packaging; conversely, the smaller the amount of bubbles after correction, the stronger the airtightness of the outer packaging. Based on the different levels of airtightness, the test samples are graded and controlled as superior, qualified, and unqualified products.

[0069] Specifically, the range of superior products and the range of qualified products are set according to the production target. The range of superior products is [0, 3ml], and the range of qualified products is (3ml, 5ml).

[0070] Specifically, for superior and qualified products: a pass signal is issued, and the product can flow into the next production stage; For non-conforming products: an alarm signal is issued and the automated rejection device, robotic arm, push rod, and diverter plate are triggered to remove the product from the production line, and improvement suggestions are provided for the non-conforming products.

[0071] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A method for monitoring the outer packaging of frozen chicken products, characterized in that, include: Place the packaging bag containing frozen chicken products into a vacuum-sealed container filled with clean water, and control the vacuum pump to conduct an air extraction test from the vacuum-sealed container. Obtain the first shrinkage speed of the packaging bag; The interval between the start time of the vacuum pump and the time when the packaging bag is placed into the vacuum sealing container is adjusted according to the first shrinkage speed of the packaging bag. The vacuum pump is controlled to actually extract air from the vacuum sealed container according to the specified interval; The inlet temperature of the actual evacuation pipe, the filtration temperature of the inlet filter, and the rate of decrease in air pressure inside the vacuum sealing tank were collected respectively. The degree of bubble destruction in the water is determined based on the inlet temperature, the filtration temperature, and the rate of decrease in air pressure, and the second amount of dissolved gas is calculated based on the rate of decrease in air pressure. The second shrinkage speed of the packaging bag is obtained again, and the first amount of gas dissolved in the packaging bag during the actual evacuation process is calculated based on the second shrinkage speed. The total amount of gas leaked from the packaging bag dissolved in water is determined based on the first amount of dissolution and the second amount of dissolution. The rotational speed of the vacuum pump is determined based on the total amount dissolved. The agitation amplitude and temperature change of the water during the vacuuming process according to the speed of the vacuum pump are obtained. The amount of bubbles released in the water is determined based on the agitation amplitude and the temperature change of the water. Adjust the height difference between the water level and the packaging bag according to the amount of bubbles produced; The monitored bubble volume is obtained, and the corrected bubble volume is determined based on the total dissolved volume, the bubble precipitation volume, and the monitored bubble volume. The sealing performance of the outer packaging of frozen chicken products is determined based on the corrected bubble amount.

2. The method for monitoring the outer packaging of frozen chicken products according to claim 1, characterized in that, The gas premature leakage solubility coefficient is the product of the shrinkage rate of the packaging bag and the preset conversion coefficient.

3. The method for monitoring the outer packaging of frozen chicken products according to claim 2, characterized in that, The interval duration is positively correlated with the solubility coefficient of the gas in case of premature leakage.

4. The method for monitoring the outer packaging of frozen chicken products according to claim 3, characterized in that, The degree of bubble destruction in the purified water is determined based on the inlet air temperature, the filtration temperature, and the rate of decrease in air pressure, including: The temperature difference between the air inlet of the extraction pipe and the inlet filter is calculated based on the air inlet temperature and the filtration temperature of the inlet filter. Compare the temperature difference with a preset temperature difference; The rate of decrease in air pressure inside the vacuum-sealed container is compared with a preset rate of decrease in air pressure. If the temperature difference is greater than the preset temperature difference, and the rate of decrease in air pressure inside the vacuum-sealed container is less than the preset rate of decrease in air pressure, then it is determined that the degree of bubble destruction in the water exceeds the allowable range.

5. The method for monitoring the outer packaging of frozen chicken products according to claim 4, characterized in that, The total amount of dissolution is the sum of the first amount of dissolution and the second amount of dissolution.

6. The method for monitoring the outer packaging of frozen chicken products according to claim 5, characterized in that, The power of the vacuum pump is negatively correlated with the overall amount of gas leaked from the packaging bag dissolved in clean water.

7. The method for monitoring the outer packaging of frozen chicken products according to claim 6, characterized in that, Determine the amount of air bubbles that are released into the water, including: The time it takes for the packaging bag to retract and generate agitation is obtained; The change in temperature is obtained during the time that the packaging bag undergoes retraction and agitation. The amount of bubbles produced is determined based on the temperature change.

8. The method for monitoring the outer packaging of frozen chicken products according to claim 7, characterized in that, When the amount of bubbles released exceeds the preset amount, the height difference between the water surface and the packaging bag is increased.

9. The method for monitoring the outer packaging of frozen chicken products according to claim 8, characterized in that, The height difference between the water surface and the packaging bag is directly proportional to the amount of bubbles produced.

10. The method for monitoring the outer packaging of frozen chicken products according to claim 9, characterized in that, The corrected bubble quantity is the sum of the difference between the monitored bubble quantity and the amount of bubble precipitation, and the amount dissolved in the water.

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