Airtightness detection method and system

Abstract

The application discloses a kind of airtightness detection method and system, it is characterized in that, the method utilizes airtightness detection system to the detection cavity of the measured piece being placed is pumped, when pumping is completed, the gas flow of pumping is detected, after gas flow detection is qualified, detection cavity pressure maintaining is carried out again, in the process of pressure maintaining, the real-time air pressure detection of detection cavity is carried out, air pressure remains stable, then the airtightness of measured piece is qualified;The airtightness of measured piece is not qualified as follows: one is that gas flow detection exceeds flow reference value, gas flow detection is judged as unqualified, two is in the process of pressure maintaining, air pressure drops and is less than air pressure reference value;The system includes detection cavity, material taking manipulator, cavity cover turnover device, cavity cover pressing device, vacuum pump, air pressure buffer tank, pumping pipeline, solenoid valve, flowmeter, air pressure sensor, detection host and pressure relief solenoid valve.The application adopts the way of combination of rough measurement and fine measurement, when measured piece breaks after pumping, by rough measurement to the gas flow of pumping, measured piece unqualified can be found in time, detection efficiency is high, when measured piece does not break after pumping, there can be slight air leakage situation, at this moment, it enters the fine measurement stage of real-time air pressure detection of pressure maintaining, so detection will be more accurate.

Description

Technical Field

[0008] ,

[0001] The present invention relates to the technical field of airtightness detection, and specifically relates to an airtightness detection method and system. Background Art

[0002] The existing airtightness detection is to put the test piece into water and determine the airtightness of the test piece by observing whether there are bubbles. This detection method has the following deficiencies: First, the test piece is directly in contact with water, which will affect the performance and quality of some test pieces; Second, it relies on manual visual inspection, resulting in a large labor intensity and is not suitable for mass detection; Third, the detection efficiency is low and it is not suitable for on-line production detection.

[0003] To solve the above problems, the patent document with the publication (announcement) number CN116183129A discloses an airtightness detection device and an airtightness detection method. In this method, a pressing power component drives the workpiece and the sealing component to fit together. The sealing component is provided with a first ventilation hole for inputting pressure into the inner cavity pipeline of the workpiece and a second ventilation hole for discharging gas. The flow sensor can detect the gas output flow rate, and the airtightness can be determined by the difference between the input flow rate and the output flow rate. By continuously introducing gas, the airtightness in the working state can be inspected. The above technical solution determines the airtightness by the difference between the input flow rate and the output flow rate, and its application scope is limited to detecting the tightness of the cavity wall of the workpiece before it is closed, and cannot detect the workpiece with a closed cavity or the packaged package, such as a sealed packaging bag or a canned food. Summary of the Invention

[0004] The purpose of the present invention is to provide an airtightness detection method and system with high detection efficiency and accuracy, which is specifically for detecting workpieces with closed cavities or packaged packages.

[0005] To solve the above technical problems, the technical solution adopted by the present invention is:

[0006] An airtightness detection method, using an airtightness detection system to evacuate the detection chamber where the test piece is placed. When the evacuation is completed, the air flow rate of the evacuation is detected. After the air flow rate detection is qualified, the detection chamber is pressurized and maintained. During the pressure maintenance process, the real-time air pressure of the detection chamber is detected. If the air pressure remains stable, the airtightness of the test piece is qualified; The situations where the airtightness of the test piece is unqualified are as follows: First, the air flow rate detection exceeds the flow reference value and the air flow rate detection is determined to be unqualified; Second, during the pressure maintenance process, the air pressure drops and is less than the air pressure reference value.

[0007] Further, the specific steps are as follows:

[0008] Step 1, Place the test piece: Use the material handling manipulator in the airtightness detection system to place the test piece into the detection chamber;

[0009] Step 2: Seal the test chamber: Use the chamber cover flipping device in the airtightness test system to fasten the chamber cover onto the test chamber to close the test chamber. Then use the chamber cover pressing device in the airtightness test system to press the chamber cover tightly to make the test chamber in a sealed state.

[0010] Step 3: Evacuate the detection chamber: Use the vacuum pump in the airtightness testing system to evacuate the pressure buffer tank. When the pressure in the pressure buffer tank reaches the preset reference value, open the solenoid valve on the evacuation pipeline to start evacuating the detection chamber.

[0011] Step 4, Air Flow Rate Detection: When the air pressure in the detection chamber reaches the preset air pressure value, the solenoid valve is closed to stop air extraction. The flow meter on the extraction pipeline automatically accumulates the current air flow rate and transmits it to the detection host. The detection host compares the air flow rate with the flow reference value. If the air flow rate is greater than the flow reference value, the air flow rate detection is deemed unqualified, and the detection ends. If the air flow rate is not greater than the flow reference value, the air flow rate detection is deemed qualified.

[0012] Step 5, Pressure Holding in the Detection Chamber: After the air flow rate is found to be within acceptable limits, the pressure in the detection chamber is held for a predetermined time.

[0013] Step 6: Real-time air pressure detection: During the pressure holding period, the air pressure sensor is used to detect the air pressure in the detection chamber in real time and transmits the air pressure detection value to the detection host. The detection host compares the air pressure detection value with the air pressure reference value. When the air pressure drops and is less than the air pressure reference value, it is determined that the air pressure detection is unqualified and the detection ends; when the air pumping flow rate is less than the flow rate reference value, it is determined that the air pressure detection is qualified and the detection ends.

[0014] Step 7: Depressurize the test chamber: After the test is completed, open the pressure relief solenoid valve on the suction line to depressurize the test chamber to normal pressure.

[0015] Step 8, Test Part Processing: After depressurizing the test chamber to atmospheric pressure, reset the chamber cover clamping device to release the seal on the test chamber, and activate the chamber cover flipping device to flip the chamber cover to open the test chamber; when the air flow rate test or the air pressure test is unqualified, the material handling robot takes the test part out of the test chamber and places it into the unqualified production box; when the air pressure test is qualified, the material handling robot takes the test part out of the test chamber and places it into the qualified production box.

[0016] Furthermore, in step 3, the preset reference value for air pressure is -95 kPa.

[0017] Furthermore, in step 4, the preset air pressure value is -95 kPa.

[0018] Furthermore, in step 4, the flow rate reference value is the average flow rate when multiple air extraction tests are completed on a qualified test sample.

[0019] Furthermore, in step 5, the predetermined pressure holding time is 1-2 minutes.

[0020] Furthermore, in step 6, the air pressure reference value is the average value of the test air pressure obtained by holding the qualified test sample under pressure multiple times.

[0021] An airtightness testing system includes a testing chamber, a material handling robot, a chamber cover flipping device, a chamber cover clamping device, a vacuum pump, a pressure buffer tank, an extraction pipeline, a solenoid valve, a flow meter, a pressure sensor, a testing host, and a pressure relief solenoid valve. The testing chamber is hinged with a chamber cover. The chamber cover flipping device flips the chamber cover to open or close the testing chamber. The chamber cover clamping device clamps the chamber cover to seal the testing chamber. The material handling robot places the workpiece into and removes it from the testing chamber. One end of the extraction pipeline is connected to the testing chamber, and the other end is connected to the pressure buffer tank, which is connected to the vacuum pump. The solenoid valve is located on the extraction pipeline. The pressure relief solenoid valve, flow meter, and pressure sensor are located on the extraction pipeline in the section between the solenoid valve and the testing chamber. The testing host is electrically connected to the solenoid valve, pressure relief solenoid valve, flow meter, and pressure sensor.

[0022] Furthermore, the detection chamber is located on the workbench surface, and the detection host is located inside the workbench; the material handling robot is a suction cup type three-axis robot, and the cavity cover flipping device is powered by a cylinder.

[0023] Furthermore, the vacuum pump is an automatic start-stop type vacuum pump, which automatically stops when the air pressure in the pressure buffer tank reaches the preset reference value, and automatically starts when the air pressure in the pressure buffer tank is lower than the preset reference value.

[0024] The beneficial effects of this invention are as follows:

[0025] This invention combines coarse and fine measurement. When the test piece breaks after air extraction, coarse measurement of the air flow rate allows for timely detection of defects, resulting in high inspection efficiency. If the test piece does not break after air extraction, there may be slight leakage; in this case, a fine measurement stage involving real-time pressure monitoring is performed, leading to more accurate detection. This invention can be applied to mass production testing, especially for online inspection on assembly lines.

[0026] (2) The present invention adopts a dry testing method, which will not affect the performance and quality of the tested part due to direct contact with water, thereby realizing non-destructive testing.

[0027] (3) This invention is mainly for testing the air tightness of test items such as medicine bottles, food packaging bottles, thermos bottles, and sealed packaging bags;

[0028] (4) In addition to the sealing ring between the cavity cover and the detection cavity, the present invention also uses the cavity cover pressing device in the airtightness detection system to press the cavity cover tightly, so that the detection cavity is in a sealed state. The sealing performance is good, and zero gas leakage can be achieved during gas extraction and pressure holding, laying the foundation for accurate detection. Attached Figure Description

[0029] The present invention will be further described with reference to the accompanying drawings, but the embodiments in the drawings do not constitute any limitation on the present invention. For those skilled in the art, other drawings can be obtained based on the following drawings without creative effort:

[0030] Figure 1 This is a schematic diagram of the airtightness detection system of the present invention;

[0031] Figure 2 This is a schematic diagram of the air path connection in the airtightness testing system of the present invention;

[0032] Figure 3 This is a flowchart of the airtightness testing method of the present invention.

[0033] In the diagram: 1. Detection chamber; 2. Material handling robot; 3. Chamber cover flipping device; 4. Chamber cover clamping device; 5. Vacuum pump; 6. Pressure buffer tank; 7. Air extraction pipeline; 8. Solenoid valve; 9. Flow meter; 10. Pressure sensor; 11. Detection host; 12. Pressure relief solenoid valve; 13. Chamber cover; 14. Worktable; 15. Cylinder. Detailed Implementation

[0034] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of this application can be combined with each other.

[0035] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper surface," "lower surface," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "forward," "reverse," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0036] An airtightness testing method involves evacuating a test chamber containing the test piece. Upon completion of evacuation, the airflow rate is measured. If the airflow rate is deemed acceptable, the test chamber is then pressurized. During the pressurization process, the air pressure in the test chamber is monitored in real time. If the air pressure remains stable, the airtightness of the test piece is considered acceptable. The following situations indicate that the airtightness of the test piece is unacceptable: first, the airflow rate exceeds a reference value, thus the airflow rate test is deemed unacceptable; second, during the pressurization process, the air pressure decreases and falls below the reference value.

[0037] like Figure 1 , 2 As shown, an airtightness testing system includes a testing chamber 1, a material handling robot 2, a chamber cover flipping device 3, a chamber cover clamping device 4, a vacuum pump 5, a pressure buffer tank 6, an air extraction pipeline 7, a solenoid valve 8, a flow meter 9, a pressure sensor 10, a testing host 11, and a pressure relief solenoid valve 12. A chamber cover 13 is hinged to the testing chamber 1. The chamber cover flipping device 3 flips the chamber cover 13 to open or close the testing chamber 1. The chamber cover clamping device 4 clamps the chamber cover 13 to keep the testing chamber 1 sealed. The material handling robot 2 is used to... The test piece is placed into the test chamber 1 and removed from the test chamber 1; one end of the suction pipe 7 is connected to the test chamber 1, and the other end is connected to the pressure buffer tank 6, which is connected to the vacuum pump 5; the solenoid valve 8 is located on the suction pipe 7; the pressure relief solenoid valve 12, the flow meter 9, and the pressure sensor 10 are located on the suction pipe 7 and in the pipe section between the solenoid valve 8 and the test chamber 1; the test host 11 is electrically connected to the solenoid valve 8, the pressure relief solenoid valve 12, the flow meter 9, and the pressure sensor 10.

[0038] The detection chamber 1 is located on the workbench 14, and the detection host 11 is located inside the workbench 14. The material handling robot 2 is a suction cup type three-axis robot, and the chamber cover flipping device 3 is powered by a cylinder 15. The vacuum pump 5 is an automatic start-stop vacuum pump. It automatically stops when the air pressure in the air pressure buffer tank 6 reaches the preset air pressure reference value of -95 kPa, and automatically starts when the air pressure in the air pressure buffer tank is lower than the preset air pressure reference value of -95 kPa.

[0039] It should be emphasized that, in addition to the pressing structure in this embodiment where the pressing block is rotated and moved downward by a motor, the cavity cover pressing device 4 can also adopt a flip-top pressing method or a cylinder-driven pressing block lifting and pressing method.

[0040] In addition to being located on the workbench, the detection chamber 1 can also adopt other structural forms, such as a hollow wall structure.

[0041] The test items can be medicine bottles, food packaging bottles, thermos bottles, sealed packaging bags, etc., and are not limited to bagged or bottled products, nor are they limited to products from any particular industry. As long as the test item requires the product to be airtight and leak-proof, it can be placed in this testing device for testing.

[0042] like Figure 3 As shown, the specific steps of the airtightness testing method are as follows:

[0043] Step 1: Place the test piece: Using the material handling robot 2 in the airtightness testing system, place the test piece into the testing chamber 1.

[0044] Step 2: Sealing the Detection Chamber: The chamber cover 13 is fastened onto the detection chamber using the chamber cover flipping device 3 in the airtightness detection system to close the detection chamber 1. Then, the chamber cover 13 is pressed tightly using the chamber cover clamping device 4 in the airtightness detection system, ensuring that the detection chamber 1 is in a sealed state. In addition to the sealing ring between the chamber cover and the detection chamber, this invention also utilizes the chamber cover clamping device in the airtightness detection system to press the chamber cover tightly, ensuring a sealed state for the detection chamber. This provides excellent sealing performance, achieving zero gas leakage during both evacuation and pressure holding, laying the foundation for accurate detection.

[0045] Step 3: Evacuate the detection chamber: Use the vacuum pump 5 in the airtightness detection system to evacuate the pressure buffer tank 6. When the pressure in the pressure buffer tank 6 reaches the preset reference value of -95Kpa, open the solenoid valve 8 on the evacuation pipeline 7 to start evacuating the detection chamber 1.

[0046] Step 4, Air Flow Rate Detection: When the air pressure in the detection chamber 1 reaches the preset air pressure value of -95 kPa, the solenoid valve 8 is closed to stop air extraction. The flow meter 9 on the air extraction pipeline 7 automatically accumulates the current air extraction flow rate and transmits the air extraction flow rate to the detection host 11. The detection host 11 compares the air extraction flow rate with the flow rate reference value. When the air extraction flow rate is greater than the flow rate reference value, the air flow rate detection is deemed unqualified, and the detection ends; when the air extraction flow rate is not greater than the flow rate reference value, the air flow rate detection is deemed qualified.

[0047] Step 5, Pressure holding in the detection chamber: After the air flow rate is qualified, the pressure in the detection chamber 1 is held for a predetermined time, which is 1 minute.

[0048] Step 6: Real-time air pressure detection: During the pressure holding period, the air pressure sensor 10 performs real-time air pressure detection on the detection chamber 1 and transmits the air pressure detection value to the detection host 11. The detection host 11 compares the air pressure detection value with the air pressure reference value. When the air pressure drops and is less than the air pressure reference value, it is determined that the air pressure detection is unqualified and the detection ends; when the air pumping flow rate is less than the flow rate reference value, it is determined that the air pressure detection is qualified and the detection ends.

[0049] Step 7, Depressurize the test chamber: After the test is completed, open the pressure relief solenoid valve 12 on the air extraction line 7 to release the negative pressure in the test chamber 1 to normal pressure.

[0050] Step 8, Test Part Processing: After the test chamber is depressurized to normal pressure, the chamber cover clamping device 4 is reset to release the seal on the test chamber 1, and the chamber cover flipping device 3 is activated to flip the chamber cover 13 to open the test chamber 1; when the air flow rate test is unqualified or the air pressure test is unqualified, the material handling robot 2 takes out the test part from the test chamber 1 and places it into the unqualified production box; when the air pressure test is qualified, the material handling robot 2 takes out the test part from the test chamber 1 and places it into the qualified production box.

[0051] Furthermore, in step 4, the flow rate reference value is the average flow rate after multiple air extraction tests on a qualified test sample. In step 6, the pressure reference value is the average test pressure obtained after multiple pressure holding tests on a qualified test sample.

[0052] Working principle: This invention uses a dry testing method, which avoids the impact of direct contact with water on the performance and quality of the tested component. This invention combines coarse and fine testing. When the tested component breaks after air extraction, the coarse measurement of the air flow rate can promptly detect the component's failure, resulting in high testing efficiency. When the tested component does not break after air extraction, there may be slight air leakage. In this case, the fine testing stage of real-time air pressure detection is performed under pressure holding, resulting in more accurate testing.

[0053] (3) This invention is mainly for testing test items such as medicine bottles, food packaging bottles, thermos bottles, and sealed packaging bags. For sealed packaging bags, such as packaging bags filled with nitrogen and food.

[0054] Furthermore, those skilled in the art can combine and integrate the different embodiments or examples described herein, as well as the features of those embodiments or examples, without contradiction. Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for detecting airtightness, characterized in that: An airtightness testing system is used to evacuate the testing chamber containing the test piece. Upon completion of evacuation, the airflow rate is measured. If the airflow rate is within acceptable limits, the testing chamber is then pressurized. During this pressure-holding process, the air pressure in the testing chamber is monitored in real time. If the air pressure remains stable, the airtightness of the test piece is considered acceptable. The following are examples of situations where the airtightness of the test piece is deemed unacceptable: 1) The airflow rate exceeds the reference value, in which case the airflow rate test is deemed unacceptable; 2) During the pressure-holding process, the air pressure drops and falls below the reference value. The specific steps are as follows: Step 1: Place the test piece: Use the robotic arm in the airtightness testing system to place the test piece into the testing chamber; Step 2: Seal the test chamber: Use the chamber cover flipping device in the airtightness test system to fasten the chamber cover onto the test chamber to close the test chamber. Then use the chamber cover pressing device in the airtightness test system to press the chamber cover tightly to make the test chamber in a sealed state. Step 3: Evacuate the detection chamber: Use the vacuum pump in the airtightness testing system to evacuate the pressure buffer tank. When the pressure in the pressure buffer tank reaches the preset reference value, open the solenoid valve on the evacuation pipeline to start evacuating the detection chamber. Step 4, Air Flow Rate Detection: When the air pressure in the detection chamber reaches the preset air pressure value, the solenoid valve is closed to stop air extraction. The flow meter on the extraction pipeline automatically accumulates the current air flow rate and transmits it to the detection host. The detection host compares the air flow rate with the flow reference value. If the air flow rate is greater than the flow reference value, the air flow rate detection is deemed unqualified, and the detection ends; if the air flow rate is not greater than the flow reference value, the air flow rate detection is deemed qualified. Step 5, Pressure Holding in the Detection Chamber: After the air flow rate is found to be within acceptable limits, the pressure in the detection chamber is held for a predetermined time. Step 6: Real-time air pressure detection: During the pressure holding period, the air pressure sensor is used to detect the air pressure in the detection chamber in real time and transmits the air pressure detection value to the detection host. The detection host compares the air pressure detection value with the air pressure reference value. When the air pressure drops and is less than the air pressure reference value, it is determined that the air pressure detection is unqualified and the detection ends. Step 7: Depressurize the test chamber: After the test is completed, open the pressure relief solenoid valve on the suction line to depressurize the test chamber to normal pressure. Step 8, Test Part Processing: After depressurizing the test chamber to normal pressure, reset the chamber cover clamping device to release the seal on the test chamber, and start the chamber cover flipping device to flip the chamber cover to open the test chamber; when the air flow rate test or the air pressure test fails, the material handling robot takes the test part out of the test chamber and places it into the failure generation box. When the air pressure test is qualified, the material handling robot takes the test piece out of the test chamber and places it into the qualified production box. The airtightness testing system includes a testing chamber, a material handling robot, a chamber cover flipping device, a chamber cover clamping device, a vacuum pump, a pressure buffer tank, an air extraction pipeline, a solenoid valve, a flow meter, a pressure sensor, a testing host, and a pressure relief solenoid valve. The testing chamber is hinged with a chamber cover. The chamber cover flipping device flips the chamber cover to open or close the testing chamber. The chamber cover clamping device clamps the chamber cover to keep the testing chamber in a sealed state. The material handling robot is used to place the test piece into the testing chamber and remove it from the testing chamber. One end of the suction pipe is connected to the testing chamber, and the other end is connected to the pressure buffer tank. The pressure buffer tank is connected to the vacuum pump. The solenoid valve is located on the suction pipe. The pressure relief solenoid valve, flow meter, and pressure sensor are located on the suction pipe in the section between the solenoid valve and the testing chamber. The testing host is electrically connected to the solenoid valve, pressure relief solenoid valve, flow meter, and pressure sensor. The testing chamber is located on the worktable, and the testing host is located inside the worktable. The material handling robot is a suction cup type three-axis robot. The chamber cover flipping device is powered by a cylinder. The vacuum pump is an automatic start-stop vacuum pump that automatically stops when the pressure in the pressure buffer tank reaches the preset reference value. It will automatically turn on when the air pressure in the air pressure buffer tank is lower than the preset reference value.

2. The airtightness testing method according to claim 1, characterized in that: In step 3, the preset reference value for air pressure is -95 kPa.

3. The airtightness testing method according to claim 1, characterized in that: In step 4, the preset air pressure is -95 kPa.

4. The airtightness testing method according to claim 1, characterized in that: In step 4, the flow rate reference value is the average flow rate when multiple air extraction tests are completed on a qualified test sample.

5. The airtightness testing method according to claim 1, characterized in that: In step 5, the pressure holding time is predetermined to be 1-2 minutes.

6. The airtightness testing method according to claim 1, characterized in that: In step 6, the air pressure reference value is the average value of the test air pressure obtained by holding the qualified test sample under pressure multiple times.

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