CN102288252A - System for testing micro leakage of sealed component - Google Patents

Abstract

The invention discloses a test system for micro-leakage of a sealing element, which includes a pressure supply system, a pressurization system, a pressure regulation system, a pressure holding test system, a pressure relief safety system and a complete machine control system, wherein the pressure supply system Provide high-pressure liquid power higher than test requirements for the tested components, the pressurization system provides a simulated working environment for the tested components, and the pressure regulating system can accurately adjust the pressure difference environment required by the tested components, further Approaching the working pressure environment of the tested component, the pressure-holding test system can measure the leakage of the liquid under the pressure-holding environment by checking the pressure change of the test liquid in the pressure-holding environment. The problem of low test precision can realize fast and precise measurement, and at the same time meet the general measurement of gas and liquid sealing components, and can accurately calculate the leakage of components per unit time.

Description

A Testing System for Micro Leakage of Sealing Components

technical field

The invention relates to a testing system for micro-leakage of a sealing element.

Background technique

In various industrial systems and the automotive industry, high pressure and vacuum work links are more common. For many components, especially valve components such as common fuel injectors in automobile engines, there is a certain allowable leakage. The leakage and allowable leakage of these components are extremely small in many cases. Through Traditional methods are difficult to detect or the cost of detection is relatively high.

At present, there are many detection equipments, such as ultrasonic leakage detection. This method is more effective for gas leakage detection, but the lower limit of detection is also very high. The detection principle is to detect the mechanical wave of a specific frequency when gas leakage is emitted. Vibration, this method is powerless for extremely small amounts of leakage. Another is to detect the concentration of gases with specific chemical properties. The limitation of this method is that the concentration of a specific gas can be detected, but the amount of leakage cannot be accurately estimated, because the leaked gas is difficult to be controlled within a certain volume. In addition, most of the gases or liquids that are non-flammable, non-toxic and chemically insensitive cannot be detected by existing technologies.

Contents of the invention

Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a test system for the micro-leakage of sealing elements, which not only solves the problem of low test precision of the traditional leak test system, but also realizes fast and precise measurement, and at the same time It meets the general measurement of gas and liquid sealing components, and can accurately calculate the leakage of components per unit time.

In order to achieve the above purpose, the present invention provides a test system for micro-leakage of sealing elements, including a pressure supply system, a pressurization system, a pressure regulation system, a pressure holding test system, a pressure relief safety system and a complete machine control system, wherein the The above-mentioned pressure supply system provides high-pressure liquid power higher than the test requirements for the tested components, the described pressurization system provides a simulated working environment for the tested components, and the described pressure regulation system can precisely adjust the pressure required by the tested components The pressure difference environment is further approaching the working pressure environment of the tested element. The pressure-holding test system can measure the leakage of the liquid under the pressure-holding environment by checking the pressure change of the test liquid in the pressure-holding environment. The pressurization system It includes an overflow valve, two pressure sensors, an electromagnetic reversing valve, a one-way valve, a liquid reservoir, a pressure control switch and several pipelines. The pressure regulating system includes two overflow valves, two An electromagnetic reversing valve, a one-way valve, a hydraulically controlled one-way valve, a pressure sensor, and a liquid reservoir, the pressure maintaining test system includes a pressure sensor, a liquid reservoir, a one-way valve, a A hydraulic control check valve, an observable pressure gauge and the tested components, the pressure relief safety system includes a hydraulic control check valve, an electromagnetic reversing valve, and an overflow valve, and the complete machine control system includes The main controller, communication bus and interface circuit, as well as various sensors and electronic control units distributed in each subsystem component, and various sensors and electronic control units inside each subsystem are connected to the main controller through the interface circuit.

Detection method of the present invention is as follows:

The first step is to install the tested component on the test head, fix it, and seal it well. If there is a lot of air inside the tested component, it is also necessary to enable the automatic exhaust function to discharge the internal gas through the flushing of the test oil.

The second step is to establish a certain pressure difference between the two ends of the tested component to be sealed, and this pressure difference can be adjusted according to the need within a certain range.

The third step is to seal the pipeline of the high-pressure part, thereby forming a continuous replenishment of a high-pressure source independent of the outside and without external pressure.

The fourth step is to conduct a pressure drop test on the pipeline of the high pressure part within a certain period of time or within a certain pressure range. The system's inspection of the leakage of the tested component is based on the principle that liquid can be compressed in a small amount. The bulk elastic modulus of the liquid, which is the reciprocal of the liquid compressibility, is an important physical quantity to describe the properties of the liquid and an important parameter to characterize the mechanical properties of the liquid material, which determines the physical properties of a series of liquid materials. This test system is This principle is used. The compressibility of the liquid is generally ignored, but it needs to be calculated accurately in this system.

Liquid compressibility k:

The modulus of elasticity of a liquid is the inverse of the compressibility:

为保压状态下测试油容积；

为被测试元器件泄漏量；

为保压状态下测试油压强变化；K为测试油弹性模量。 Where: k is the compressibility of the test oil;

To test the oil volume under the pressure-holding state;

Leakage of the tested component;

is the pressure change of the test oil under pressure; K is the elastic modulus of the test oil.

是根据预估的被测试元件的泄漏量进行设计的，体积过大则压降偏小，体积过小有可能压降剧烈。系统中测试油弹性模量K可通过实验获得，系统压降

通过压力传感器测量，则泄漏量

可计算得到： The volume of the sealed environment within the system

It is designed according to the estimated leakage of the tested component. If the volume is too large, the pressure drop will be small, and if the volume is too small, the pressure drop may be severe. The elastic modulus K of the test oil in the system can be obtained through experiments, and the system pressure drop

Measured by the pressure sensor, the leakage

Can be calculated to get:

The beneficial effects of the present invention are: adopting the above-mentioned system, the test system not only solves the problem of low test precision of the traditional leakage test system, realizes fast and precise measurement, but also satisfies the universal measurement of gas and liquid sealing components, and The leakage of components per unit time can be accurately calculated.

The present invention can be further configured such that the pressure source of the pressure supply system can be provided by the frequency conversion hydraulic pump that comes with the system, or can be provided by an external pressure source through a switch.

The present invention can further be configured such that a filtering system, a cooling system and a liquid level indicating device are arranged in the liquid reservoir.

The present invention can further be configured to also include a leaking liquid recovery pipeline and a filtering device.

Description of drawings

Fig. 1 is a schematic structural diagram of the system assembly of the present invention;

Fig. 2 is a schematic diagram of the system startup mode of the present invention;

Fig. 3 is a schematic diagram of the pressurization mode of the system of the present invention;

Fig. 4 is a schematic diagram of the system pressure regulating mode of the present invention;

Fig. 5 is a schematic diagram of the pressure holding test mode of the system of the present invention;

Fig. 6 is a schematic diagram of the pressure relief mode of the system of the present invention;

Fig. 7 is a schematic diagram of the standby mode of the system of the present invention.

Among them: 1 is the main oil tank, 2 is the liquid level gauge, 3 is the oil suction port filter, 4 is the thermometer, 5 is the motor, 6 is the oil pump, 7 is the overflow valve, 8 is the pressure gauge, and 9 is the three-position four-way electromagnetic Commutator, 10 is a one-way valve, 11 is a liquid reservoir, 12 is a pressure relay, 13 is a hydraulic control one-way valve, 14 is a two-position four-way electromagnetic reversing valve, and 15 is a tested component.

Detailed ways

The invention provides a test system for the micro-leakage of sealing elements, including a pressure supply system, a pressurization system, a pressure regulation system, a pressure holding test system, a pressure relief safety system and a complete machine control system, wherein the pressure supply system Provide the tested element 15 with high-pressure hydraulic power higher than the test requirement, the pressurization system provides a simulated working environment for the tested element 15, and the pressure regulating system can precisely adjust the pressure difference required by the tested element 15 Environment, further approaching the working pressure environment of the tested element 15, the pressure holding test system can measure the leakage of the liquid under the pressure holding environment by checking the pressure change of the test liquid in the pressure holding environment, and the pressurization system includes A relief valve 7, two pressure gauges 8, a three-position four-way electromagnetic commutator 9, a check valve 10, a liquid reservoir 11, a pressure control switch and several pipelines, the pressure regulating system It includes two overflow valves 7, a three-position four-way electromagnetic commutator 9, a two-position four-way electromagnetic directional valve 14, a check valve 10, a hydraulic control check valve 13, a pressure gauge 8, a Liquid reservoir 11, wherein the pressurization system and the pressure regulation system share a relief valve 7, a pressure gauge 8, a three-position four-way electromagnetic commutator 9, a check valve 10, a liquid reservoir 11, a pressure control switch and corresponding pipelines, the pressure holding test system includes two pressure gauges 8, a liquid reservoir 11, a check valve 10, a hydraulic control check valve 13, and a tested element 15. The pressure safety system includes a hydraulically controlled one-way valve 13, a two-position four-way electromagnetic reversing valve 14, and a relief valve 7. The complete machine control system includes a master controller, a communication bus and an interface circuit, and is distributed in each Various sensors and electronic control units in the subsystem components, various sensors and electronic control units in each subsystem are connected with the general controller through interface circuits. The pressure source of the pressure supply system can be provided by the frequency conversion hydraulic pump that comes with the system, or can be provided by an external pressure source through a switch. A filtering system, a cooling system and a liquid level indicating device are arranged in the liquid reservoir. The pressurization system is regulated by the three-position four-way electromagnetic commutator 9 controlled by the general controller, and the pressurization degree can be adjusted arbitrarily. The pressure regulation threshold of the pressure regulating system is completed by the general controller controlling the three-position four-way electromagnetic commutator 9 and then controlling the hydraulic control check valve 13 . The pressure regulating system includes a liquid return system, and the liquid return system is provided with a two-position four-way electromagnetic reversing valve 14 and an overflow valve 7 to prevent system pressure sudden changes and pulsations. In the pressure maintaining circuit of the pressure maintaining test system, only one check valve 10 and one hydraulically controlled check valve 13 communicate with the outside world, which avoids system self-leakage during the pressure maintaining process and improves measurement precision. The test environment has reserved a multi-parameter adjustable test system, which can comprehensively judge the leakage of the tested component 15 according to the pressure-holding seal volume, the type of test liquid and the pressure drop value per unit time. If the acceptance conditions are given, it can also be directly used as To check the use of the instrument, the volume of the pressure-holding test system needs to be adjusted according to the allowable leakage of the tested element 15. The purpose of the adjustment is to make the selection of parameters such as sensor and pressure gauge range more targeted. The test system is also equipped with a leakage recovery pipeline and an oil suction port filter 3, which can recover and reuse the test liquid leaked out of the components.

Work process of the present invention is as follows:

1. Start the test system

Figures 1 and 2 show the working principle of the test system after startup. When the start button of the whole machine is pressed, the control system of the whole machine will perform a self-test. If there is no abnormality in each system, it will enter the start-up procedure. At this time, if there is no abnormality in the liquid level gauge 2 and the thermometer 4, then the motor 5 starts, and the oil pump 6 starts to supply oil. The speed of the motor 5 is determined by the frequency converter according to the requirements of the control system of the whole machine. Generally speaking, the starting speed is relatively low to achieve the purpose of energy saving. The test oil enters the test pipeline through the oil suction port filter 3 and the oil pump 6. At this time, the overflow valve 7 is in the minimum opening state and does not overflow, the test oil returns to the main oil tank 1 through the three-position four-way electromagnetic commutator 9, and the pressure gauge indicates zero.

2. The system enters the pressurized working state

As shown in Figures 1 and 3, it is the schematic diagram of the pressurized state after the test system is started. The pressurized state is a necessary step in the whole process of testing. When the tested element 15 needs to be tested, the tested element must first be 15 After clamping to the test head, turn on the test button, and the master controller will guide the system to automatically complete a series of operations such as pressurization, pressure regulation, test and pressure relief.

After entering the pressurization operation state, the motor 5 automatically adjusts the pressurization speed according to the pressurization demand. Generally speaking, if the test pressure required by the tested element 15 is high, the pressurization speed is relatively high, and the test pressure is low. relatively low. Such a design can effectively shorten the overall test time, provide efficiency and save energy. Under the pressurized state, the spool of the three-position four-way electromagnetic commutator 9 moves to the right, and the passage for the test oil to enter the test environment is opened. At this time, the high-pressure test oil is full of the test environment pipeline. When the test oil pressure exceeds the preset test pressure value, the three-position four-way electromagnetic commutator 9 will automatically move the spool to the left. At this time, the passage of the test oil to the test pipeline is closed, and the test oil returns from the oil return pipe to the main fuel tank 1. the

3. The system enters the pressure regulation state

After the pressurized state is over, the general controller will adjust the system to quickly enter the pressure regulating state to adjust the test oil pressure in the test pipeline. Figures 1 and 4 are schematic diagrams of the test system entering the pressure regulation state after startup, at this time the pressurization motor 5 rotates at a very low speed to reduce energy consumption and provide kinetic energy for the hydraulic control check valve 13 at the same time. The 9 spools of the three-position four-way electromagnetic commutator continue to move to the left, and the pressure regulating branch is opened. According to the preset pressure limit, excess test oil will overflow from the hydraulic control check valve 13 and flow back to the main oil tank 1 from the overflow valve 7 through the two-position four-way electromagnetic reversing valve 14 . After the adjustment of the hydraulically controlled one-way valve 13, the pipeline pressure in the test environment is precisely positioned at the required pressure value, so as to enter the next test environment.

4. The system enters the pressure holding test state

This state is the most important link in the whole work process and also a link that directly draws the eligibility conclusion. Figures 1 and 5 are schematic diagrams of the test system entering the pressure-holding test state after startup. At this time, the test oil is completely closed by a check valve 10 and a hydraulic control check valve 13. If the tested components are not considered The leakage of the system itself is required to be zero. In this state, there are two methods of testing. One is to adhere to the standard of the closed test oil pressure drop value per unit time, that is, within the specified time of the unit, such as 5 minutes, the hydraulic pressure drop value must be less than a certain design value to consider the system qualified; the other The first method is to investigate the time required to drop the unit pressure, that is, the time required for the test oil to drop the unit pressure, such as 1bar, in the test environment.

When working with the first test method, the total controller starts counting at the initial time of the test, stops the counting and measures the drop value of the liquid pressure according to the requirements of the tested element 15 at a specified time such as 5 minutes, and can be obtained by the above formula It is convenient to calculate the leakage of the tested element 15. Wherein, the elastic modulus of the test liquid can be obtained according to experiments or by consulting a manual.

5. The system enters the pressure relief state

After the test is completed, the system will display the test results and then automatically perform the pressure relief operation to enter the next test session. Figures 1 and 6 are schematic diagrams of the test system entering the pressure relief state after startup, at this time the pressurization motor 5 rotates at a very low speed to reduce energy consumption and provide kinetic energy for the hydraulic control check valve 13 at the same time. The spool of the three-position four-way electromagnetic commutator 9 moves to the left, the pressure relief branch is completely conducted, and the excess test oil will overflow from the hydraulic control check valve 13 and flow back from the overflow valve 7 through the two-position four-way electromagnetic commutator valve 14 to main tank 1. The function of the pressure relief operation is to reduce the pressure in the test environment, facilitate the disassembly of the tested component 15, and reduce the risk of operation.

6. System standby

After the pressure relief operation, the system needs to automatically enter a standby environment so that the next test operation can be started quickly. Figures 1 and 7 are schematic diagrams of the test system entering the pressure relief state after startup. After the pressure relief operation is completed, the general controller adjusts the test system to a standby low power consumption mode. Now the electric motor 5 and the oil pump 6 pump oil at idle speed, and the motor speed is determined by the frequency converter according to the requirements of the complete machine control system, and the lower speed is to consider energy saving. The test oil passes through the oil suction port filter 3 and the oil pump 6 and enters the test pipeline. At this time, the overflow valve 7 is in the minimum opening state and does not overflow, the test oil returns to the main oil tank 1 through the three-position four-way electromagnetic commutator 9, and the pressure gauge indicates zero. If you do not need to use the test system for a long time, you can directly shut down the power supply.

The advantage of this test system lies in its high sensitivity. Usually, the elastic modulus of the test liquid is very large. For example, the K value of the general oil-based test liquid is as high as 1.4~2×10 ³ Mpa, so the instant leakage is extremely small. After multiplying the K value, it is also placed in hundreds of millions. Times, coupled with a high-precision pressure sensor can detect extremely small leaks.

In order to improve the accuracy of the testing system, it must be required that the internal self-sealing of the system is better, and there must be no leakage or the self-leakage is much lower than the leakage of the tested element 15 . In the present invention, a check valve 10 and a hydraulically controlled check valve 13 are specially designed to seal the tested oil.

The control system of the whole machine in the present invention will work with a pre-set program, automatically detect parameters such as time and pressure changes, and time the leakage, which is more accurate and efficient than the direct detection of leakage in previous products. Compared with the existing technology of directly detecting leakage substances, the present invention has greater advantages in mechanism.

Claims (4)

1. A test system for micro-leakage of sealing elements, characterized in that it comprises a pressure supply system, a pressurization system, a pressure regulation system, a pressure holding test system, a pressure relief safety system and a complete machine control system, wherein the pressure The supply system provides high-pressure liquid power higher than the test requirements for the tested components, the pressurization system provides a simulated working environment for the tested components, and the pressure regulation system can accurately adjust the pressure difference environment required by the tested components , further approaching the working pressure environment of the tested element, the pressure-holding test system can measure the leakage of the liquid under the pressure-holding environment by checking the pressure change of the test liquid under the pressure-holding environment, and the pressurization system includes an overflow Flow valve, two pressure sensors, an electromagnetic reversing valve, a check valve, a liquid reservoir, a pressure control switch and several pipelines, the pressure regulating system includes two overflow valves, two electromagnetic reversing valves directional valve, a one-way valve, a hydraulically controlled one-way valve, a pressure sensor, and a liquid reservoir, and the pressure maintaining test system includes a pressure sensor, a liquid reservoir, a one-way valve, a hydraulic Directional valve, an observable pressure gauge and tested components, the pressure relief safety system includes a hydraulically controlled check valve, an electromagnetic reversing valve, and an overflow valve, and the complete machine control system includes a master controller , communication bus and interface circuit, and various sensors and electronic control units distributed in each subsystem component, and various sensors and electronic control units inside each subsystem are connected to the general controller through the interface circuit. 2. A test system for micro-leakage of sealing elements according to claim 1, characterized in that: the pressure source of the pressure supply system can be provided by the frequency conversion hydraulic pump that comes with the system, or can be provided by the outside through the switch Stressors provided. 3 . The system for testing micro-leakage of sealing elements according to claim 1 , wherein a filtering system, a cooling system and a liquid level indicating device are arranged in the liquid reservoir. 4 . 4 . The system for testing micro-leakage of sealing elements according to claim 1 , further comprising a leak recovery pipeline and a filter device. 5 .

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