CN116878770A - Air tightness detection method and device - Google Patents
Air tightness detection method and device Download PDFInfo
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- CN116878770A CN116878770A CN202310896506.4A CN202310896506A CN116878770A CN 116878770 A CN116878770 A CN 116878770A CN 202310896506 A CN202310896506 A CN 202310896506A CN 116878770 A CN116878770 A CN 116878770A
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- 238000001514 detection method Methods 0.000 title claims abstract description 52
- 238000012360 testing method Methods 0.000 claims abstract description 37
- 238000012545 processing Methods 0.000 claims abstract description 34
- 230000009471 action Effects 0.000 claims abstract description 27
- 238000000034 method Methods 0.000 claims abstract description 22
- 230000008569 process Effects 0.000 claims description 5
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- 230000008859 change Effects 0.000 description 19
- 238000013461 design Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 238000007789 sealing Methods 0.000 description 3
- 238000005259 measurement Methods 0.000 description 2
- 230000035945 sensitivity Effects 0.000 description 2
- 230000006641 stabilisation Effects 0.000 description 2
- 238000011105 stabilization Methods 0.000 description 2
- 230000000087 stabilizing effect Effects 0.000 description 2
- 238000009825 accumulation Methods 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M3/00—Investigating fluid-tightness of structures
- G01M3/02—Investigating fluid-tightness of structures by using fluid or vacuum
- G01M3/26—Investigating fluid-tightness of structures by using fluid or vacuum by measuring rate of loss or gain of fluid, e.g. by pressure-responsive devices, by flow detectors
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- Examining Or Testing Airtightness (AREA)
Abstract
The invention discloses a method and a device for detecting air tightness, wherein the device comprises the following steps: the device comprises a control processing module, an execution module, a cavity module, a gas circuit connecting channel and a pressure sensor; the control processing module is connected with the execution module and the pressure sensor, the execution module is connected with the cavity module, the cavity module is connected with the pressure sensor, and the cavity module is connected with the object to be tested through the gas path connecting channel; the control processing module is used for sending a detection instruction to the execution module and outputting an air tightness test result according to the pressure signal; the execution module is used for receiving the detection instruction and generating an execution action according to the detection instruction; the cavity module comprises a cavity, wherein the cavity is used for changing the volume of the cavity under the action of executing actions; and the pressure sensor is used for detecting the pressure in the cavity to obtain a pressure signal and transmitting the pressure signal to the control processing module. The invention can realize the air tightness detection of the product.
Description
Technical Field
The invention relates to the field of air tightness detection, in particular to an air tightness detection method and device.
Background
The detection of tightness of products or parts is widely required in industrial production, such as products with waterproof grade requirements, products with sealing requirements and cavities or pipelines, and the like, in order to ensure the sealing quality of the manufactured products in the production process, the tightness of the processed products or parts is required to be detected, the optimal detection mode is that the products cannot be damaged or polluted, and the most common mode in industry is to test the gas leakage quantity of the products to measure the tightness of the products, namely the tightness detection.
The air tightness or leakage of a product is normally measured in terms of leakage volume per minute, typically in milliliters per minute. However, since most products require very high air tightness, the amount of leakage allowed is very small, even down to the order of a few thousandths of a milliliter per minute, it becomes impractical to directly test the amount of leakage for air tightness detection using a device such as a flowmeter, because the flowmeter cannot measure such low flow rates at all. Therefore, when the tightness of the product is detected, the leakage of the gas volume is usually detected in a mode of converting the leakage of the gas volume into the change of the gas pressure according to the principle of a gas state equation.
Based on the above detection principle, there are two methods for implementing the airtight detection scheme in the current technology, namely, a direct pressure method and a differential pressure method. The direct pressure method is to directly use the air pressure of an air source, after passing through a pressure reducing valve, the air tightness measuring system with the product placed or connected is inflated and pressurized to a certain air pressure level (target pressure), then the air source is disconnected, after a certain time (balance time) of pressure stabilization, the pressure is kept for a certain time (detection time) for detecting the pressure change, if the product leaks during the period, the air pressure value can be changed in the pressure maintaining time due to the leaked air, at this time, whether the product exceeds the air tightness specification can be judged according to the air pressure change, and the specific leakage amount can be calculated according to an air state equation so as to determine the leakage level of the product.
The differential pressure method is to pressurize a standard and a test article to the same target pressure by the air source, then disconnect the air source at the same time, after a certain time of pressure stabilization, keep the pressure for a period of time, and measure the pressure difference between the test article and the standard article by the differential pressure sensor, so as to judge whether the test article has leakage.
The disadvantage of the current solution is that when the air tightness measurement system is pressurized by means of an air source (typically the air source output by an air compressor), it is not known or not known exactly how much volume of air is filled/extracted into the test system before the system reaches the target pressure (the system pressurization process, which is actually the process of filling the system with air). This has a problem that if there is a large leakage of the product, the product leakage is completed before the pressure balance is stabilized during the inflation pressurization, and then the pressure change cannot be detected in the pressure maintaining stage (detection stage), that is, no leakage occurs, so that the product with a large leakage amount is misjudged as a qualified product. On the other hand, because the air source adopted by the current scheme is usually an air source of an air compressor, the pressure and the flow of the air source are large, the pressure and the flow of an input test system are controlled through a pressure reducing valve, the control precision is insufficient, the system stabilizing time after pressurization can be longer, so that many designs also design a large air volume to stabilize the air pressure, the design complexity and the cost are increased, the pressure change caused by the leakage of a small product is small when the test system tests a product with a small volume (the volume of the relatively increased air volume), the detection sensitivity is very poor, and in fact, the current air tightness detection equipment usually cannot accurately detect the air tightness of the product with the small volume.
Disclosure of Invention
The invention aims to provide a method and a device for detecting air tightness, which aim to solve the problems in the air tightness detection.
The present invention provides an air tightness detection device, comprising:
the device comprises a control processing module, an execution module, a cavity module, a gas circuit connecting channel and a pressure sensor;
the control processing module is connected with the execution module and the pressure sensor, the execution module is connected with the cavity module, the cavity module is connected with the pressure sensor and the gas path connecting channel, and the gas path connecting channel is connected with an object to be tested;
the control processing module is used for sending a detection instruction to the execution module and outputting an air tightness test result according to the pressure signal;
the execution module is used for receiving the detection instruction and generating an execution action according to the detection instruction;
the cavity module is used for changing the volume of the cavity under the action of executing the action;
and the pressure sensor is used for detecting the pressure in the cavity to obtain a pressure signal and transmitting the pressure signal to the control processing module.
A method of detecting air tightness, comprising:
sending a detection instruction to an execution module through a control processing module, and outputting an air tightness test result according to a pressure signal;
receiving a detection instruction through an execution module, and generating an execution action according to the detection instruction;
changing the volume of the cavity through the cavity module under the action of executing the action;
and detecting the pressure in the cavity through a pressure sensor to obtain a pressure signal, and sending the pressure signal to a control processing module.
By adopting the embodiment of the invention, the air tightness detection of the product can be realized.
The foregoing description is only an overview of the present invention, and is intended to provide a more clear understanding of the technical means of the present invention, as it is embodied in accordance with the present invention, and to make the above and other objects, features and advantages of the present invention more apparent, as it is embodied in the following detailed description of the invention.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the present invention, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic view of an air tightness detection device according to an embodiment of the present invention;
fig. 2 is a schematic diagram of an air tightness detection device according to an embodiment of the present invention.
Detailed Description
The technical solutions of the present invention will be clearly and completely described in connection with the embodiments, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Device embodiment
According to an embodiment of the present invention, there is provided an air tightness detection device, fig. 1 is a schematic diagram of the air tightness detection device according to the embodiment of the present invention, as shown in fig. 1, specifically including:
the device comprises a control processing module, an execution module, a cavity module, a gas circuit connecting channel and a pressure sensor;
the control processing module is connected with the execution module and the pressure sensor, the execution module is connected with the cavity module, the cavity module is connected with the pressure sensor and the gas path connecting channel, and the gas path connecting channel is connected with an object to be tested;
the control processing module is used for sending a detection instruction to the execution module and outputting an air tightness test result according to the pressure signal;
the execution module is used for receiving the detection instruction and generating an execution action according to the detection instruction;
the cavity module is used for changing the volume of the cavity under the action of executing the action;
and the pressure sensor is used for detecting the pressure in the cavity to obtain a pressure signal and transmitting the pressure signal to the control processing module.
The number of the cavity module, the execution unit, the pressure sensor and the gas path connecting channels is at least 1.
The specific implementation method is as follows:
the invention designs a cavity capable of accurately controlling volume change by a controller in a certain range in the air tightness detection equipment, and when in test, the product to be tested is connected to the cavity in an air tightness manner to form a total air tightness test system, and at the moment, the air tightness test system can be pressurized or depressurized by properly controlling the volume change of the cavity (when the product is tested by utilizing negative pressure, a negative pressure environment is needed to be created by depressurization), so that the system reaches the target test pressure. The greatest difference between the technical scheme and the existing technical scheme is that the pressurizing mode of the air tightness testing system is changed, and the technical scheme has the greatest advantages that the volume and the speed which are changed during pressurizing are completely controlled and known, namely, for a completely non-leakage system, according to a gas state equation, the gas pressure in the air tightness testing system during or after pressurizing is completely calculated and predicted, namely, the volume change and the pressure change of the system have corresponding relations. That is, if there is a leak (including leakage of the product) in the airtight test system, the actually measured gas pressure in the system deviates from the pressure value estimated from the volume change, thereby determining that the leak occurs.
In the technical scheme, the target pressure after the system volume is changed can be predicted, and if the product with larger leakage quantity leaks in the pressurizing or depressurizing process, the final pressure of the system is certainly deviated from the predicted target pressure, so that the product can be directly judged to leak. There is no need to determine the leakage of the product by the pressure drop during dwell time (since no pressure drop occurs during dwell time if a quick leak has been completed).
In addition, the speed of changing the pressure by directly changing the volume of the air tightness testing system is controllable, the mode of changing the system pressure is mild and is also very direct, and the gas path on-off is controlled in a mode of not adopting a switching gas valve, so that the system pressure fluctuation is very small, the pressure can be quickly stabilized after pressurization, no extra gas volume is needed for stabilizing the pressure, the total volume of the whole air tightness testing system can be very small, no extra gas dead space is generated, and the accurate leakage test can be carried out on products with very small volume.
The scheme has the advantages that an external air source is not needed, so that the air tightness detection equipment can be used in a scene without an air source of an air compressor. Because the controllable cavity of the air tightness testing equipment and the air path system of the tested product are connected into a whole air path system during testing, the air tightness testing equipment can also calculate the total volume capacity of the whole air tightness measuring system (including products) through self-checking, so that the optimal measuring parameters are automatically set for the tested products with different sizes, the measuring sensitivity is higher, and the result is more accurate.
FIG. 2 is a schematic diagram of an air tightness detection device according to an embodiment of the present invention;
in the embodiment of the technical scheme, as shown in fig. 2, a standard-shaped cylinder can be arranged in the air tightness test equipment, a movable sealing piston is arranged in the cylinder, and the volume of the measurement system can be changed when the piston moves. Meanwhile, in order to achieve the purpose of accurately controlling the volume change, a servo motor capable of accurately controlling the movement position is arranged in the system to serve as a power device, and the servo motor is connected with a piston of the air cylinder and used for driving the piston of the air cylinder to move so as to controllably change the volume in the air cylinder, so that the pressure of the whole airtight system is controllably obtained. A pressure sensor is provided for detecting pressure changes in the airtight system in real time. And the processing and control unit is used for controlling the motion of the servo motor and calculating and judging the leakage of the system according to the received pressure sensor data and the pressure change.
According to the invention, the gas circuit system can be pressurized or depressurized to the designated target test pressure according to the user requirement, and after the pressure is stable, the leakage speed of the product is judged by detecting the pressure change speed or the pressure accumulation change amount in a certain time, so that whether the leakage of the product meets the specification requirement is judged, namely, the air tightness is measured by a direct pressure method.
When testing products with large leak rate specifications (typically in milliliters per minute), the direct pressure method cannot perform a stable test because the leak rate is large, which can lead to rapid pressure changes. The invention can also control the servo motor to push the cylinder piston at a certain speed, so that the cylinder outputs a constant-speed output quantitative gas volume (which is generally equal to the specification of the leakage rate of the product), and meanwhile, the leakage rate of the product can be judged whether to meet the specification requirement or not through the system pressure change detected by the pressure sensor. If the pressure detected by the pressure sensor increases along with the pushing of the piston, the actual leakage rate of the product is judged to be smaller than the leakage rate specification of the product, and the product meets the requirement, otherwise, the actual leakage rate of the product is larger than the leakage specification of the product, and the product does not meet the requirement.
The volume and the speed of the invention which are changed during pressurization are completely controlled and known, namely, for a system which is not leaked at all, according to a gas state equation, the gas pressure in the air tightness test system during pressurization or after pressurization is completely predictable, namely, the volume change and the pressure change of the system have corresponding relations. That is, if there is a leak (including leakage of the product) in the airtight test system, the actually measured gas pressure in the system deviates from the pressure value estimated from the volume change, thereby determining that the leak occurs.
Method embodiment
The invention discloses an air tightness detection method, which specifically comprises the following steps:
the control processing module sends a detection instruction to the execution module, receives the pressure signal, processes the pressure signal, and outputs an air tightness test result after the processing is completed;
receiving a detection instruction through an execution module, and generating an execution action according to the detection instruction;
changing the volume of the cavity in the cavity module by performing an action;
and detecting the pressure in the cavity through a pressure sensor to obtain a pressure signal, and sending the pressure signal to a control processing module.
The volume of the cavity is changed by the piston under the action of the executing action.
And the execution action generated by the execution module through the detection instruction is linear motion.
The temperature information is collected through the temperature sensor and sent to the control processing module, and the control processing module compensates the influence of temperature on the air tightness test according to the temperature information.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; and these modifications or substitutions may be made to the technical solutions of the embodiments of the present invention without departing from the spirit of the corresponding technical solutions.
Claims (8)
1. An air tightness detection device, characterized by comprising:
the device comprises a control processing module, an execution module, a cavity module, a gas circuit connecting channel and a pressure sensor;
the control processing module is connected with the execution module and the pressure sensor, the execution module is connected with the cavity module, the cavity module is connected with the pressure sensor, and the cavity module is connected with the object to be tested through the gas path connecting channel;
the control processing module is used for sending a detection instruction to the execution module, receiving the pressure signal, processing the pressure signal and outputting an air tightness test result after the processing is finished;
the execution module is used for receiving the detection instruction and generating an execution action according to the detection instruction;
the cavity module comprises a cavity and is used for changing the volume of the cavity under the action of executing actions;
and the pressure sensor is used for detecting the pressure in the cavity to obtain a pressure signal and transmitting the pressure signal to the control processing module.
2. The apparatus of claim 1, wherein the cavity module comprises a piston that changes the volume of the cavity under the action of the performing action.
3. The apparatus of claim 1, wherein the execution module generates the execution action as a linear motion according to the detection instruction.
4. The device of claim 1, comprising a temperature sensor coupled to the control processing module for collecting temperature information and transmitting the temperature information to the control processing module, the control processing module compensating for the effect of temperature on the air tightness detection result based on the temperature information.
5. A method of detecting air tightness, comprising:
the control processing module sends a detection instruction to the execution module, receives the pressure signal, processes the pressure signal, and outputs an air tightness test result after the processing is completed;
receiving a detection instruction through an execution module, and generating an execution action according to the detection instruction;
changing the volume of the cavity in the cavity module by performing an action;
and detecting the pressure in the cavity through a pressure sensor to obtain a pressure signal, and sending the pressure signal to a control processing module.
6. The method of claim 5, wherein the volume of the cavity is changed by a piston under the action of the performing action.
7. The method of claim 6, wherein the execution motion generated by the execution module via the detection instruction is linear motion.
8. The method of claim 7, wherein the method further comprises: the temperature information is collected through the temperature sensor and sent to the control processing module, and the control processing module compensates the influence of temperature on the air tightness test according to the temperature information.
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| CN202310896506.4A CN116878770A (en) | 2023-07-20 | 2023-07-20 | Air tightness detection method and device |
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| CN202310896506.4A CN116878770A (en) | 2023-07-20 | 2023-07-20 | Air tightness detection method and device |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117990301A (en) * | 2024-04-03 | 2024-05-07 | 宁德时代新能源科技股份有限公司 | Air tightness detection system |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN117990301A (en) * | 2024-04-03 | 2024-05-07 | 宁德时代新能源科技股份有限公司 | Air tightness detection system |
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