CN107340101B - Gas micro-leakage detection device and method for sealing device - Google Patents

Abstract

The invention discloses a device and a method for evaluating micro gas leakage of a sealing device, and belongs to the field of leakage testing of sealing devices. The device comprises a cavity, a sealing device, vacuumizing equipment, a vacuum meter, a vacuum display and a computer. The cavity is connected with the sealing device through a connecting joint, the cavity is connected with the vacuum meter through the connecting joint, and the cavity is connected with the vacuumizing equipment through the connecting joint. The vacuum meter and the vacuum display are connected through a cable, and the vacuum display is connected with the computer through a cable. The connecting joint is provided with a stop valve. The vacuum pumping equipment is connected with the computer through a cable. The computer is provided with vacuum degree testing and analyzing software and vacuumizing control software. Also discloses a method for evaluating the gas micro-leakage of the sealing device based on the gas micro-leakage evaluating device. The invention provides a device and a method for testing and evaluating the sealing performance of a sealing device, which have the advantages of high testing precision, high sensitivity and adjustable sensitivity and can give quantitative results for micro-leakage conditions.

Description

A device and method for detecting gas micro-leakage of a sealing device

technical field

The invention relates to a gas micro-leakage detection device and method of a sealing device, in particular to a gas micro-leakage detection device and method of a sealing device applied to aero-engines, and belongs to the field of sealing device leakage testing and evaluation methods.

Background technique

In the research of aero-engine sealing technology, the development and production of sealing devices, the evaluation of sealing performance is involved, especially the air tightness characteristics of sealing devices (such as end-face sealing devices, circumferential sealing devices, etc.) must be detected and tested. Carry out the detection and test of the air tightness characteristics of the sealing device. The existing technology mainly uses the method of counting bubbles to evaluate the sealing performance. The number of bubbles within the specified time does not exceed the agreed number, and the sealing performance of the product is considered to be qualified (such as a certain type of aero-engine). The sealing device requires less than 10 bubbles in 5 minutes). The devices corresponding to this detection and test method include: standard origin, standard gas tank, standard air filter, standard switch, standard pressure gauge 1, standard pressure gauge 2, air inlet sealing cavity, sealing device, air outlet sealing cavity, Connect the tube and beaker, see Figure 1.

The method of counting the bubbles and the corresponding device have the problem that the test accuracy is not high enough when evaluating the leakage of the sealing device. For example, different sealing devices or the same device have different bubble sizes under different conditions, and the number of bubbles can only give a qualitative leak state. evaluation, and can not give accurate leakage value.

With the advancement of aero-engine technology, higher requirements are put forward for the development and production of sealing devices and their test technology research. In the field of aero-engine sealing, the demand for technical research to improve sealing performance and the development and production of micro-leakage sealing devices is increasingly emerging. These requirements objectively require the study of micro-leakage, high-precision testing methods and devices, and the application of such methods and devices to evaluate the performance of sealing devices.

SUMMARY OF THE INVENTION

The technical problem to be solved by the device and method for detecting gas micro-leakage of a sealing device disclosed in the present invention is to provide a device and method for testing the sealing performance of aero-engine sealing device, which has the advantages of high test accuracy, high sensitivity and adjustable sensitivity , and can give quantitative results for the micro-leakage situation.

The purpose of the present invention is achieved through the following technical solutions.

A gas micro-leakage detection device of a sealing device disclosed by the invention includes a cavity, a sealing device, a vacuuming device, a vacuum meter, a vacuum display and a computer. The cavity body and the sealing device are connected through a connecting joint, the cavity body and the vacuum gauge are connected through a connecting joint, and the cavity body and the vacuum pumping device are connected through a connecting joint. The vacuum gauge and the vacuum display are connected by a cable, and the vacuum display and the computer are connected by a cable. The connecting joint is provided with a stop valve. The vacuuming device and the computer are connected by cables. The computer is equipped with vacuum degree testing and analysis software and vacuum pumping control software.

The described vacuum degree testing and analysis software has the following two functions: (1) making a vacuum degree-time relationship curve, and storing the data files of vacuum degree and corresponding time; Calculation and extraction include curve fitting function, tangent slope, secant slope, and curved edge trapezoidal area calculation functions, and the sealing performance of the sealing device is investigated and evaluated with the characteristic parameters. (2) Calculation function of gas leakage rate (mol/s) in selected time period.

The vacuum pumping control software has the following functions: the vacuum pumping control software issues commands to control the vacuum pumping equipment to discharge the air in the cavity out of the cavity through the connecting joint.

A method for evaluating gas micro-leakage of a sealing device is realized based on the gas micro-leakage evaluation device of a sealing device disclosed in the present invention. During operation, open the stop valve on the connection joint, open the vacuum control software installed on the computer, and then use the vacuum pump. The control software controls the vacuuming device to discharge the air in the cavity through the connecting joint to the outside of the cavity. When the vacuum indicator shows that the vacuum degree is the preset pressure value, close the shut-off valve on the connection joint to ensure that the gas does not flow in the reverse direction. The air outside the cavity only leaks into the cavity through the end face sealing surface and the circumferential sealing surface of the sealing device, thereby causing the change of vacuum degree. The method of vacuum degree is used to test and evaluate the sealing performance of the sealing device. The end face sealing surface And the circumferential sealing surface is the leakage air inlet. Run the vacuum degree test and analysis software for evaluating the sealing device of the computer, and record the relationship curve between vacuum degree and time and the corresponding data. The length of the test time is determined according to the test requirements of the aero-engine sealing device. The characteristic parameters are extracted from the relationship between vacuum degree and time to test and evaluate the sealing characteristics of the aero-engine sealing device.

The vacuum display shows that the preset pressure value of vacuum degree is preferably 0.008Pa.

The method of using the vacuum degree to test and evaluate the sealing performance of the sealing device is implemented as follows: according to the relationship curve between the vacuum degree and time, the leakage amount in any period of time within the preset time is calculated and obtained. The relationship between the vacuum degree and time is obtained by fitting according to the test data, that is, the relationship between the vacuum degree P and the time t is P=f(t). According to the test data, the cavity during the test is obtained by fitting. The relationship between the internal gas temperature T and the time t is T=Φ(t). Accordingly, the leakage rate (expressed in moles/second) through the end face sealing surface and the circumferential sealing surface of the sealing device into the cavity 1 in the time period from t ₁ to t is obtained as shown in formula 1).

In formula 1)

Substitute equations 2) and 3) into equation 1) to obtain equation 4)

According to formula 4) combined with the test data, the leakage rate of the sealing device can be obtained.

According to the relationship curve between vacuum degree and time, the leakage amount of any time period within a preset time can be calculated to provide quantitative leakage amount data for the development of aero-engine sealing device, and then evaluate the leakage performance of the aero-engine sealing device to be installed. It also provides quantitative reference for the selection of engines installed on different manufacturers and different batches of products.

Under the condition that the temperature remains unchanged, since the existing sealing leakage method can observe air bubbles in the water container, for the convenience of comparison, the volume of one air bubble leaked corresponding to the existing sealing leakage evaluation method is set. The vacuum degree result table is obtained by calculating the volume of a bubble leaked by the existing sealing leakage method. The volume of different cavities, under the condition of one bubble volume corresponding to the existing sealing leakage evaluation method, has different changes in vacuum degree. Selecting the appropriate cavity volume for different aero-engine sealing devices can realize the adjustable sensitivity of the leakage test, adjust the appropriate sensitivity and give high-precision leakage test results.

Beneficial effects:

1. A sealing device gas micro-leakage detection device disclosed in the present invention has the advantages of simple structure and easy implementation.

2. Compared with the existing sealing leakage evaluation method with several bubbles, the gas micro-leakage detection device and method of the sealing device disclosed in the present invention can quantitatively evaluate the quality of the sealing device based on the vacuum degree-time relationship curve obtained by the test. , Selecting the appropriate cavity volume for different aero-engine sealing devices can realize the adjustable sensitivity of the leakage test, which has the advantages of high test accuracy, high sensitivity and adjustable sensitivity, and can give quantitative results for the micro-leakage situation.

3. The device and method for detecting gas micro-leakage of a sealing device disclosed in the present invention can give quantitative results on the micro-leakage of aero-engine sealing device, and will have a positive supporting effect on the development, testing and evaluation of aero-engine sealing device, It can also provide an effective performance comparison method and method for the installation of aero-engine parts (sealing devices). This device and method can be used to evaluate the leakage performance of the aero-engine sealing device to be installed, and it can be used for different manufacturers and different batches. The selection of the engine installed on the product provides a quantitative reference.

Description of drawings

Fig. 1 is the existing leak test method of sealing device in the background technology and the corresponding device;

FIG. 2 is a schematic diagram of a gas micro-leakage detection device of a sealing device disclosed in the present invention.

Detailed ways

In order to better illustrate the purpose and advantages of the present invention, the content of the invention will be further described below with reference to the accompanying drawings and examples.

Example 1:

As shown in FIG. 2 , a sealing device gas micro-leakage detection device disclosed in this embodiment includes a cavity 1 , a sealing device 2 , a vacuuming device 5 , a vacuum gauge 7 , a vacuum display 9 and a computer 14 . Vacuum gauge 7 and vacuum display 9 are microcomputer-based digital display composite vacuum gauges produced by Chengdu Zhenghua Electronic Instrument Co., Ltd., numbered ZDF-X-LED. The cavity 1 and the sealing device 2 are connected through the connecting joint 8 , the cavity 1 and the vacuum gauge 7 are connected through the connecting joint 6 , and the cavity 1 and the vacuum pumping device 5 are connected through the connecting joint 3 . The vacuum gauge 7 and the vacuum display 9 are connected by a cable 10 , and the vacuum display 9 and the computer 14 are connected by a cable 11 . The connecting joint 3 is provided with a stop valve. The vacuuming device 5 and the computer 14 are connected through the cable 12 . The computer 14 is installed with vacuum degree testing and analysis software and vacuum pumping control software.

The described vacuum degree testing and analysis software has the following two functions: (1) making a vacuum degree-time relationship curve, and storing the data files of vacuum degree and corresponding time; Calculation and extraction include curve fitting function, tangent slope, secant slope, and curved edge trapezoidal area calculation functions, and the sealing performance of the sealing device is investigated and evaluated with the characteristic parameters. (2) Calculation function of gas leakage rate (mol/s) in selected time period.

The vacuum pumping control software has the following functions: the vacuum pumping control software issues commands to control the vacuum pumping device 5 to discharge the air in the cavity 1 out of the cavity through the connecting joint 3 .

A method for detecting gas micro-leakage of a sealing device based on a gas micro-leakage detection device of a sealing device disclosed in the present invention, during operation, open the stop valve on the connection joint 3, and open the vacuum pumping control software installed on the computer 14. The vacuuming control software controls the vacuuming device 5 to discharge the air in the cavity 1 out of the cavity through the connecting joint 3 . When the vacuum indicator 9 shows that the vacuum degree is 0.008Pa, close the stop valve on the connection joint 3 to ensure that the gas will not flow in reverse. The air outside the cavity 1 only leaks into the cavity 1 through the end face sealing surface and the circumferential sealing surface of the sealing device 2, thereby causing the change of the vacuum degree. The vacuum degree method is used to test and evaluate the sealing performance of the sealing device. The circumferential sealing surface and the end surface sealing surface are the leakage air inlet 4 . Run the vacuum degree test and analysis software for sealing device evaluation of the computer 14 to record the relationship curve between vacuum degree and time and the corresponding data. The length of the test time is determined according to the test requirements of the aero-engine sealing device. The characteristic parameters are extracted from the relationship curve of vacuum degree and time to test and detect the sealing characteristics of the aero-engine sealing device.

If the end face sealing device of a certain type of aero-engine is to be tested and inspected, the end face sealing device is installed at the position of the sealing device 2 of the device of the present invention through a special tool, and the vacuum control software installed on the computer 14 issues commands to control the The vacuuming device 5 discharges the air in the cavity 1 out of the cavity through the connecting joint 3 . When the vacuum indicator 9 shows that the vacuum degree is 0.008Pa, close the stop valve on the connection joint 3 to ensure that the gas does not flow in reverse. Run the computer 14 vacuum degree test and analysis software, save the vacuum degree-time relationship data, set the sampling time to 10 minutes, the sampling frequency to 10 seconds, the vacuum degree test and analysis software displays the vacuum degree-time relationship curve, the curve The vacuum degree corresponding to the last 5 minutes can reflect the sealing performance of the end face sealing device of this type of aero-engine. A large vacuum degree indicates that the sealing device product has poor sealing performance. On the contrary, a small vacuum degree indicates that the sealing device product is tight. excellent.

The method of using the vacuum degree to test and detect the sealing performance of the sealing device is as follows: according to the relationship curve between the vacuum degree and time, the leakage amount of any time period within 10 minutes is calculated, which is the development of the aero-engine sealing device. Provides quantitative leak data. Set the vacuum degree-time curve in the cavity 1 obtained by the test, which is obtained by fitting according to the test data, that is, the relationship between the vacuum degree P and the time t is P=f(t), which is fitted according to the test data. The relationship between the gas temperature T inside the cavity and the time t during the test is obtained as T=Ф(t). Accordingly, the leakage rate (expressed in moles per second) through the end face sealing surface and the circumferential sealing surface of the sealing device into the cavity 1 in the time period from t ₁ to t can be obtained as shown in Equation 1).

In formula 1)

Substitute equations 2) and 3) into equation 1) to obtain equation 4)

According to formula 4) combined with the test data, the leakage rate of the sealing device can be obtained.

Under the condition that the temperature remains unchanged, because the existing sealed leak detection method can observe air bubbles in the water container, for the convenience of comparison, a bubble is set to leak corresponding to the existing method (assuming that the diameter of the bubble is 4 mm and the pressure is 1 atmosphere) According to the volume of different cavity 1, the vacuum degree results are calculated as shown in Table 1 below.

Table 1 Leakage of a bubble cavity vacuum change

The results in Table 1 show that for different cavity volumes, under the condition of one bubble volume corresponding to the existing sealing leak detection method, the change of vacuum degree is different. The larger the volume, the smaller the change of vacuum degree; The bigger the change. Therefore, the sensitivity of the leakage test of the method and the device of this embodiment is adjustable, and an appropriate cavity volume can be selected for different aero-engine sealing devices, and an appropriate sensitivity and a high-precision leakage test result can be given.

It can also be seen from Table 1 that applying the gas micro-leakage evaluation device and detection method of a sealing device disclosed in this embodiment, under the condition that there is only one bubble leakage volume corresponding to the existing detection method, even if the volume of the cavity 1 is relatively small. In the case of large (21205750.412mm ³ ), its sensitivity is also high, reaching 0.1596Pa.

The above-mentioned specific descriptions further describe the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above-mentioned descriptions are only specific embodiments of the present invention, and are not intended to limit the protection of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (4)

1. A method for detecting micro gas leakage of a sealing device adopts a leakage detection device which comprises a cavity (1), a sealing device (2), vacuumizing equipment (5), a vacuum meter (7), a vacuum display (9) and a computer (14); the vacuum cavity is characterized in that the cavity (1) is connected with the sealing device (2) through a connecting joint (8), the cavity (1) is connected with the vacuum meter (7) through a connecting joint (6), and the cavity (1) is connected with the vacuumizing equipment (5) through a connecting joint (3); the vacuum meter (7) is connected with the vacuum display (9) through a cable (10), and the vacuum display (9) is connected with the computer (14) through a cable (11); a stop valve is arranged on the connecting joint (3); the vacuum pumping equipment (5) is connected with the computer (14) through a cable (12); the computer (14) is provided with vacuum degree testing and analyzing software and vacuumizing control software; the method is characterized in that:

the detection method for the micro gas leakage of the sealing device comprises the following steps: when the vacuum pump works, the stop valve on the connecting joint (3) is opened, the vacuumizing control software installed on the computer (14) is opened, and the vacuumizing control software controls the vacuumizing equipment (5) to discharge air in the cavity (1) out of the cavity through the connecting joint (3); when the vacuum display (9) displays that the vacuum degree is a preset pressure value, the stop valve on the connecting joint (3) is closed to ensure that the gas cannot reversely flow in; the external air of the cavity (1) enters the cavity (1) only through the end face sealing surface and the circumferential sealing surface of the sealing device (2) through leakage, so that the change of the vacuum degree is caused, the sealing performance of the sealing device is tested and evaluated by adopting a vacuum degree method, and the circumferential sealing surface and the end face sealing surface are leakage air inlets (4); operating vacuum degree testing and analyzing software for evaluating a sealing device of a computer (14), and recording a relation curve of the vacuum degree and time and corresponding data; the length of the test time is determined according to the test requirements of the sealing device of the aircraft engine; extracting characteristic parameters according to a relation curve of vacuum degree and time to test and evaluate the sealing characteristic of the aeroengine sealing device;

the method for testing and evaluating the sealing performance of the sealing device by adopting the vacuum degree comprises the following specific implementation method,

calculating the leakage amount of any time interval section within preset time according to the relation curve of the vacuum degree and the time; the relation curve of the vacuum degree and the time is obtained by fitting according to test data, namely the relation of the vacuum degree P and the time T is P ═ f (T), and the relation of the gas temperature T in the cavity in the test process and the time T is T ═ phi (T) by fitting according to the test data; from this, t is obtained₁The leakage rate of the end face sealing face and the circumferential sealing face of the sealing device into the cavity (1) in the time period t

As shown in formula 1);

in formula 1)

Substituting formulae 2) and 3) into formula 1) to obtain formula 4)

Obtaining the leakage rate of the sealing device according to the formula 4) by combining the test data;

under the condition that the temperature is kept unchanged, because the existing sealing leakage detection method can observe bubbles in the water container, for the convenience of comparison, the volume of leaking one bubble corresponding to the existing sealing leakage evaluation method is set, and a vacuum degree result table is obtained by calculation according to the volumes of different cavities (1) and the volume of leaking one bubble by the existing sealing leakage method; the volume of different cavities (1) is different in vacuum degree change value under the condition that the volumes of the different cavities correspond to the volume of one bubble of the existing sealing leakage evaluation method, and the larger the volume is, the smaller the vacuum degree change is; conversely, the smaller the volume, the larger the change of the vacuum degree; the sensitivity of the leakage test is adjustable by selecting proper cavity volume aiming at different aeroengine sealing devices, the proper sensitivity is adjusted, and the leakage test result is given.

2. The method of claim 1, wherein the step of detecting the micro-leakage of the gas from the sealing device comprises the steps of: the vacuum degree testing and analyzing software has the following functions: making a vacuum degree-time relation curve, and storing a data file of the vacuum degree and the corresponding time; carrying out characteristic calculation and extraction on a vacuum degree-time curve, wherein the characteristic calculation and extraction comprises a curve fitting function, a tangent slope, a secant slope and a curve trapezoidal area calculation function, and inspecting and evaluating the sealing performance of the sealing device according to the characteristic parameters; a function of calculating a gas leak rate over a selected time period;

the vacuumizing control software has the following functions: the vacuumizing control software sends out a command to control the vacuumizing equipment (5) to discharge the air in the cavity (1) out of the cavity through the connecting joint (3).

3. The method of detecting a gas microleakage in a sealed device according to claim 2, wherein: the vacuum display (9) displays that the vacuum degree is 0.008Pa when the preset pressure value is selected.

4. A method of detecting a gas microleakage in a sealed device, as defined in claim 3, wherein: the leakage rate of any time period in the preset time is calculated according to the relation curve of the vacuum degree and the time, quantitative leakage rate data are provided for the development of the sealing device of the aircraft engine, the leakage performance of the sealing device to be installed on the aircraft engine is evaluated, and quantitative reference is provided for the selection of engines installed on different manufacturers and different batches of products.

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