Closed product low-pressure inflation sealing detection system and method

Abstract

The invention belongs to the technical field of sealing detection of closed products, and discloses a low-pressure inflation sealing detection system for closed products, which is structurally characterized in that a nitrogen cylinder is used as a gas source input, and gas is divided into a pressurizing gas path and a control gas path after the required pressure is adjusted by a nitrogen pressure gauge; a precise pressure regulating valve, a flow regulating valve and a flow meter are sequentially arranged on the pressurizing gas path, then the pressurizing gas path is divided into a plurality of parallel inflating channels, a direct-acting two-position three-way electromagnetic valve and an induction check valve are sequentially arranged on each inflating channel in the gas flowing direction, and the tail end of each inflating channel is connected with a tested product to inflate the tested product; the multiple control gas paths are arranged in parallel, and each control gas path comprises a pilot-operated type two-position three-way electromagnetic valve communicated to the corresponding induction check valve and controls opening and closing of the corresponding induction check valve. The precise digital display pressure gauge is adopted, the low-pressure detection effect is obvious, and errors are extremely small; operation is convenient, one-key operation is achieved, multiple gas paths are carried out at the same time and are independent of one another without interference, and detection reliability is high.

Description

Technical Field

[0001] The present invention belongs to the technical field of sealing detection of sealed products, and relates to a low-pressure inflation sealing detection system and method for sealed products. Background Art

[0002] In the existing technology, sealed products are tested for sealing using a U-shaped pressure gauge. The required testing tool is large, takes up space and cannot be moved; the test efficiency is low, only one product can be tested at a time, and the preparation time is too long; the low-pressure test results are not obvious, the test error is large, and the operation process is cumbersome. Summary of the Invention

[0003] (1) Purpose of the invention

[0004] The purpose of the present invention is to complete the low-pressure sealing test of the product with a method that is easy and fast to operate, highly efficient, and highly precise, and the results are intuitively displayed in numbers, thereby improving work efficiency, improving test accuracy, and facilitating operators to intuitively interpret test results.

[0005] (2) Technical solution

[0006] In order to solve the above technical problems, the present invention provides a low-pressure inflation seal detection system for sealed products, which includes: a nitrogen cylinder 14, a nitrogen pressure gauge 13, a charging air circuit and a control air circuit. The nitrogen cylinder 14 is used as a gas source input. After being adjusted to the required pressure by the nitrogen pressure gauge 13, the gas is divided into a charging air circuit and a control air circuit; the charging air circuit is sequentially provided with a precision pressure regulating valve 11, a flow regulating valve 7 and a flow meter 8, and then divided into multiple parallel charging channels. A direct-acting two-position three-way solenoid valve 9 and an induced check valve 5 are sequentially provided on each charging channel along the gas flow direction. The end of each charging channel is connected to the product to be tested to inflate the product to be tested; there are multiple control air circuits, which are arranged in parallel. Each control air circuit includes a pilot two-position three-way solenoid valve 10 connected to the induced check valve 5 to control the opening and closing of the induced check valve 5.

[0007] Furthermore, the rear side of the nitrogen pressure gauge 13 is connected to a filter 12 to filter impurities in the gas.

[0008] Furthermore, in the pressurized gas circuit, a dryer 6 is provided between the precision pressure regulating valve 11 and the flow regulating valve 7. The gas flows into the precision pressure regulating valve 11 to adjust the gas pressure to the pressure value required by the product being tested and then enters the dryer 6 for drying.

[0009] Furthermore, on the inflation channel, a precision digital pressure gauge 4 and a quick-connect connector 2 are sequentially arranged on the air path between the induced check valve 5 and the end of the inflation channel. The precision digital pressure gauge 4 and the quick-connect connector 2 are connected by a pneumatic hose 3, and the quick-connect connector 2 is connected to the connector 1 of the product to be tested.

[0010] Furthermore, the gas dried by the dryer 6 passes through the flow regulating valve 7 and the flow meter 8 to observe and adjust the gas flow entering the channel 1. Thereafter, the gas passes through the direct-acting two-position three-way solenoid valve 9 and enters the induced check valve 5 to wait for the control gas circuit to take effect. Then, the gas flows through the precision digital pressure gauge 4 to detect the gas pressure of the channel 1, and finally enters the connector 1 of the product to be tested through the pneumatic hose 3 and the quick-plug connector 2.

[0011] Furthermore, in the control air circuit, the gas flows out from the filter 12 into the pilot-operated two-position three-way solenoid valve 10 and flows into the induced check valve 5, controlling the opening and closing of the induced check valve 5, so that the pressurized air circuit gas passes through the induced check valve 5 and finally enters the connector 1 of the product under test to complete the inflation.

[0012] Furthermore, the induced check valve 5, the direct-acting two-position three-way solenoid valve 9 and the pilot two-position three-way solenoid valve 10 are controlled by a programmable circuit to realize the functions of inflation, pressure boosting, pressure maintenance and exhaust of the gas in the gas circuit; the precision pressure regulating valve 11 is manually adjusted; the precision digital pressure gauge 4 integrates pressure measurement, display, analog quantity transmission output and alarm output functions.

[0013] Furthermore, when the inflation of the pressurized air circuit is completed, the detected pressure value in the precision digital pressure gauge 4 reaches the requirement, the induced check valve 5, the direct-acting two-position three-way solenoid valve 9, and the pilot two-position three-way solenoid valve 10 are disconnected and no more inflation is carried out, and the gas is maintained in the tested product connector 1, the quick-connect connector 2, the pneumatic hose 3, and the precision digital pressure gauge 4 for pressure maintenance, and the air pressure value in the channel 1 is monitored by the precision digital pressure gauge 4.

[0014] Furthermore, when the pressurized gas circuit is exhausted, the pilot-operated two-position three-way solenoid valve 10 is controlled by the programmable circuit to allow gas to enter the induced check valve 5 so that the induced check valve 5 opens the circuit. The induced check valve 5 and the direct-acting two-position three-way solenoid valve 9 form a passage for gas discharge, completing the exhaust operation.

[0015] The present invention also provides a low-pressure inflation seal detection method for sealed products based on the above-mentioned detection system, in which the product to be tested is connected to the test product connector 1 of the inflation channel, and the pressure is reduced once through the pressure reducing valve on the nitrogen bottle 14, and the output pressure is 0.2MPa. The nitrogen enters the detection system through the pipeline, and is reduced twice through the precision pressure regulating valve 11 on the detection system, and the output pressure is 40KPa. The nitrogen enters the test product through the direct-acting two-position three-way solenoid valve 9, the induced check valve 5, the precision digital pressure gauge 4, and the air path; when the pressure of the test product reaches the set pressure, the system automatically closes the direct-acting two-position three-way solenoid valve 9, cuts off the air path, and the precision digital pressure gauge 4 detects the pressure inside the test product in real time. After the pressure gauge number stabilizes, the timing starts and the pressure is maintained for 20 minutes. The product sealing is judged to be qualified based on the change in pressure value.

[0016] (3) Beneficial effects

[0017] The low-pressure inflation seal detection system and method for sealed products provided by the above technical solution have small equipment dimensions, do not take up space and can be moved; no preparation time is required, and testing can be carried out by connecting the products, and 4 products can be tested at the same time, which is highly efficient; the use of a precision digital pressure gauge has obvious low-pressure detection effects and extremely small errors; it is easy to operate, with one-button operation, and multiple gas paths are carried out simultaneously, independently of each other and without interference, and the detection reliability is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a pneumatic principle diagram of a low-pressure inflation seal detection system for sealed products according to an embodiment of the present invention.

[0019] Figure 2 1 is a pressure change curve at different times under two input pressures in an embodiment of the present invention. DETAILED DESCRIPTION

[0020] In order to make the purpose, content and advantages of the present invention more clear, the specific implementation methods of the present invention are further described in detail below with reference to the accompanying drawings and examples.

[0021] Reference Figure 1 As shown, the low-pressure inflation seal detection system for sealed products in this embodiment includes a nitrogen cylinder 14, a nitrogen pressure gauge 13, a charging air circuit and a control air circuit. The nitrogen cylinder 14 is used as a gas source input. After being adjusted to the required pressure by the nitrogen pressure gauge 13, the gas is divided into a charging air circuit and a control air circuit; the charging air circuit is sequentially provided with a precision pressure regulating valve 11, a flow regulating valve 7 and a flow meter 8, and then divided into multiple parallel inflation channels. A direct-acting two-position three-way solenoid valve 9 and an induced check valve 5 are sequentially provided on each inflation channel along the gas flow direction. The end of each inflation channel is connected to the product to be tested to inflate the product to be tested; there are multiple control air circuits, which are arranged in parallel. Each control air circuit includes a pilot two-position three-way solenoid valve 10 connected to the induced check valve 5 to control the opening and closing of the induced check valve 5.

[0022] The rear side of the nitrogen pressure gauge 13 is connected to a filter 12 for filtering to reduce impurities in the gas.

[0023] In the pressurized gas circuit, a dryer 6 is provided between the precision pressure regulating valve 11 and the flow regulating valve 7. The gas flows into the precision pressure regulating valve 11 to adjust the gas pressure to the pressure value required by the product being tested, and then enters the dryer 6 for drying.

[0024] On the inflation channel, the air path between the induction check valve 5 and the end of the inflation channel is sequentially equipped with a precision digital pressure gauge 4 and a quick-connect connector 2. A pneumatic hose 3 connects the precision digital pressure gauge 4 and the quick-connect connector 2, which is then connected to the connector 1 of the product under test. The dried gas passes through a flow control valve 7 and a flow meter 8 to monitor and regulate the flow rate entering channel 1. The gas then passes through a direct-acting, two-position, three-way solenoid valve 9 and enters the induction check valve 5, where it waits for the control air path to take effect. The gas then flows through the precision digital pressure gauge 4 to detect the gas pressure in channel 1, and finally enters the connector 1 of the product under test through the pneumatic hose 3 and quick-connect connector 2.

[0025] In the control air circuit, the gas flows out from the filter 12 into the pilot-operated two-position three-way solenoid valve 10 and flows into the induction check valve 5, controlling the opening and closing of the induction check valve 5 so that the pressurized air circuit gas passes through the induction check valve 5 and finally enters the connector 1 of the product under test to complete the inflation.

[0026] In this embodiment, the induced check valve 5, the direct-acting two-position three-way solenoid valve 9 and the pilot-operated two-position three-way solenoid valve 10 are controlled by a programmable circuit to realize the functions of inflation, pressure boosting, pressure maintenance and exhaust of the gas in the gas circuit; the precision pressure regulating valve 11 is manually adjusted; the precision digital pressure gauge 4 integrates pressure measurement, display, analog quantity transmission output and alarm output functions.

[0027] When the inflation is completed, the detection pressure value in the precision digital pressure gauge 4 reaches the test requirement, and the induced check valve 5, the direct-acting two-position three-way solenoid valve 9, and the pilot two-position three-way solenoid valve 10 are disconnected to stop the system from inflating, and the gas is kept in the tested product connector 1, the quick-connect connector 2, the pneumatic hose 3, and the precision digital pressure gauge 4 for pressure maintenance. At this time, the air pressure value in channel 1 can be monitored by the precision digital pressure gauge 4.

[0028] During exhaust, the pilot-operated two-position three-way solenoid valve 10 is controlled by the programmable circuit to allow gas to enter the induced check valve 5 so that the induced check valve 5 opens. At this time, the induced check valve 5 and the direct-acting two-position three-way solenoid valve 9 form a passage for gas discharge, completing the exhaust operation.

[0029] In this embodiment, the system adopts the dry air method, using a nitrogen cylinder as the gas source, connecting the product to be tested to the system, and the system is connected to the nitrogen cylinder. The pressure reducing valve on the nitrogen cylinder is used for a first decompression, and the output pressure is 0.2MPa. Nitrogen enters the system through the pipeline, and is decompressed twice through the precision pressure reducing valve on the system, and the output pressure is 40KPa. Nitrogen enters the product to be tested through the solenoid valve, the induction check valve, the pressure gauge, and the air path. When the pressure of the product to be tested reaches the set pressure, the system automatically closes the solenoid valve, cuts off the air path, and the precision digital pressure gauge detects the pressure inside the product to be tested in real time. After the pressure gauge number stabilizes, the timing starts, the pressure is maintained for 20 minutes, and the product sealing is judged to be qualified based on the change in the pressure value. The system of this embodiment adopts a four-way independent air path system and control program, which can control and detect 4 products to be tested at the same time.

[0030] In the low-pressure inflation seal detection method for sealed products in this embodiment, a seal self-test test is first performed, and then a product seal test test is performed.

[0031] During the sealing self-test, open the nitrogen bottle valve and adjust the nitrogen pressure reducer pressure to 0.2MPa; adjust the gas line input pressure to above 40KPa by turning the pressure reducing valve knob, and inflate. When the set pressure value is reached, the equipment automatically cuts off the gas line and performs a pressure holding test. Set the pressure gauge value to be stable as the test 0 point, and hold the pressure for 20 minutes. Perform the first set of tests, and adjust the gas line input pressure to above 20KPa for the second set of tests. Each set of tests is performed five times. The test results are shown in Table 1:

[0032] Table 1 Sealing self-test results Unit: KPa

[0033]

[0034]

[0035] It can be seen from the data in the table that the system has good sealing performance. Under the two conditions of input pressure of 40KPa and 20KPa, the pressure in the system did not drop after 20 minutes of pressure maintenance. The pressure value fluctuated slightly, and the fluctuation range did not exceed 2KPa. This may be caused by changes in the test environment temperature.

[0036] In order to further test the sealing performance of the system, a pressure test was conducted, with input pressures of 40KPa and 20KPa respectively. The pressure test was conducted every 300 seconds to observe the pressure changes. The specific situation is as follows: Figure 2 As shown in the figure, under the two input pressures and different holding times, the pressure value did not drop below the initial input pressure value. Moreover, as the holding time increased, the pressure value did not change significantly, and the fluctuation range remained within ±0.2 kPa, indicating that there was no gas leakage in the system and the sealing performance was good.

[0037] During the product sealing test, pressures of 40 kPa and 20 kPa were input, respectively. Nitrogen gas was injected into the tested products through a solenoid valve, an induction check valve, and a pressure gauge. The four tested products were connected to different channels. When the pressure of the tested products reached the set pressures of 40 kPa and 20 kPa, the inflation device automatically closed the solenoid valve, cutting off the gas path. A precision digital pressure gauge monitored the internal pressure of the tested products in real time. After the pressure gauge reading stabilized, the timing began. After 20 minutes, the pressure values ​​were observed every 300 seconds (test results are shown in Table 2). It can be seen that the pressure values ​​of the four products decreased slightly as the pressure holding time increased, but did not fall below the initial input pressure value, indicating good product sealing.

[0038] Table 2 Product sealing test results Unit: KPa

[0039]

[0040] After test analysis, the system itself has good sealing performance, and has functions of inflation preservation, sealing test and air replacement; parameters such as input pressure, detection pressure, and detection time can be set. The digital pressure gauge has a range of 0-50KPa and an accuracy of 0.1KPa. The system has 4 test interfaces and can measure four products at the same time, greatly improving application efficiency.

[0041] It can be seen from the above technical solution that the present invention abandons the long-used U-type pressure gauge detection method, and for the first time uses the air circuit with a precision digital pressure gauge to perform low-pressure air tightness detection on the product; reasonably selects the component design, and cooperates with the electrical control to realize the addition of the air tightness detection function, the inflation and preservation function and the air replacement function, thereby expanding the scope of use; one-button unified operation and independent operation design of each circuit improve the detection efficiency and improve the detection reliability.

[0042] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A low-pressure inflation seal detection system for sealed products, characterized in that: include: A nitrogen cylinder (14), a nitrogen pressure gauge (13), a pressurized gas circuit and a control gas circuit are provided. The nitrogen cylinder (14) is used as a gas source input. After the gas is adjusted to a required pressure by the nitrogen pressure gauge (13), the gas is divided into a pressurized gas circuit and a control gas circuit. A precision pressure regulating valve (11), a flow regulating valve (7) and a flow meter (8) are sequentially arranged on the pressurized gas circuit, and then the pressure regulating valve (11) is divided into multiple parallel charging channels. A direct-acting two-position three-way solenoid valve (9) and an induction check valve (5) are sequentially arranged on each charging channel along the gas flow direction. The end of each charging channel is connected to a product to be tested to inflate the product to be tested. The control gas circuit has multiple channels, which are arranged in parallel. Each control gas circuit includes a pilot-operated two-position three-way solenoid valve (10) connected to the induction check valve (5) to control the opening and closing of the induction check valve (5).

2. The low-pressure inflation seal detection system for sealed products according to claim 1, characterized in that: The rear side of the nitrogen pressure gauge (13) is connected to a filter (12) for filtering impurities in the gas.

3. The low-pressure inflation seal detection system for sealed products according to claim 2, characterized in that: In the pressurized gas circuit, a dryer (6) is provided between the precision pressure regulating valve (11) and the flow regulating valve (7). The gas flows into the precision pressure regulating valve (11) to adjust the gas pressure to the pressure value required by the product being tested, and then enters the dryer (6) for drying.

4. The low-pressure inflation seal detection system for sealed products according to claim 3, characterized in that: On the inflation channel, a precision digital pressure gauge (4) and a quick-connect connector (2) are sequentially provided on the air path between the induction check valve (5) and the end of the inflation channel. The precision digital pressure gauge (4) and the quick-connect connector (2) are connected via a pneumatic hose (3), and the quick-connect connector (2) is connected to the connector (1) of the product to be tested.

5. The low-pressure inflation seal detection system for sealed products according to claim 4, characterized in that: The gas dried by the dryer (6) passes through a flow control valve (7) and a flow meter (8) to observe and adjust the gas flow entering the channel 1. Thereafter, the gas passes through a direct-acting two-position three-way solenoid valve (9) and enters the induction check valve (5) to wait for the control gas circuit to take effect. The gas then flows through a precision digital pressure gauge (4) to detect the gas pressure in the channel 1, and finally enters the connector (1) of the product to be tested through a pneumatic hose (3) and a quick-connect connector (2).

6. The low-pressure inflation seal detection system for sealed products according to claim 5, characterized in that: In the control gas circuit, gas flows out of the filter (12) into the pilot-operated two-position three-way solenoid valve (10) and flows into the induction check valve (5), thereby controlling the opening and closing of the induction check valve (5) so that the pressurized gas in the gas circuit passes through the induction check valve (5) and finally enters the connector (1) of the product to be tested to complete the inflation.

7. The low-pressure inflation seal detection system for sealed products according to claim 6, characterized in that: The induced check valve (5), the direct-acting two-position three-way solenoid valve (9) and the pilot-operated two-position three-way solenoid valve (10) are controlled by a programmable circuit to realize the functions of filling, boosting, maintaining pressure and exhausting the gas in the gas circuit; the precision pressure regulating valve (11) is manually adjusted; and the precision digital pressure gauge (4) integrates the functions of pressure measurement, display, analog quantity transmission output and alarm output.

8. The low-pressure inflation seal detection system for sealed products according to claim 7, characterized in that: When the inflation of the pressurized gas circuit is completed, the pressure value detected in the precision digital pressure gauge (4) reaches the requirement, and the induction check valve (5), the direct-acting two-position three-way solenoid valve (9), and the pilot-operated two-position three-way solenoid valve (10) are disconnected and no more inflation is carried out, and the gas is kept in the tested product connector (1), the quick-connect connector (2), the pneumatic hose (3), and the precision digital pressure gauge (4) to maintain the pressure, and the air pressure value in the channel 1 is monitored by the precision digital pressure gauge (4).

9. The low-pressure inflation seal detection system for sealed products according to claim 8, characterized in that: When the pressurized gas circuit is exhausted, the pilot-operated two-position three-way solenoid valve (10) is controlled by the program-controlled circuit to allow gas to enter the induction check valve (5) so that the induction check valve (5) is opened, and the induction check valve (5) and the direct-acting two-position three-way solenoid valve (9) form a passage for gas exhaust, thereby completing the exhaust operation.

10. A method for detecting the low-pressure inflation seal of a sealed product based on the detection system of claim 9, characterized in that: The product to be tested is connected to the product to be tested connector (1) of the inflation channel, and the pressure is reduced once through the pressure reducing valve on the nitrogen bottle (14), and the output pressure is 0.2MPa. The nitrogen enters the detection system through the pipeline, and is reduced twice through the precision pressure regulating valve (11) on the detection system, and the output pressure is 40KPa. The nitrogen enters the product to be tested through the direct-acting two-position three-way solenoid valve (9), the induction check valve (5), the precision digital pressure gauge (4), and the air path; when the pressure of the product to be tested reaches the set pressure, the system automatically closes the direct-acting two-position three-way solenoid valve (9), cuts off the air path, and the precision digital pressure gauge (4) detects the pressure inside the product to be tested in real time. After the pressure gauge number stabilizes, the timing starts, and the pressure is maintained for 20 minutes. The product sealing is judged to be qualified based on the change in the pressure value.

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