CN111413027A - Accelerated degradation test method for pressure annunciator - Google Patents
Accelerated degradation test method for pressure annunciator Download PDFInfo
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- CN111413027A CN111413027A CN202010322300.7A CN202010322300A CN111413027A CN 111413027 A CN111413027 A CN 111413027A CN 202010322300 A CN202010322300 A CN 202010322300A CN 111413027 A CN111413027 A CN 111413027A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L27/00—Testing or calibrating of apparatus for measuring fluid pressure
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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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Abstract
The invention belongs to the instrument test technology, and particularly relates to a performance accelerated degradation test method of a pressure annunciator. The accelerated degradation test method of the pressure annunciator comprises the steps of placing the pressure annunciator in a sealed environment, carrying out heating and pressurizing accelerated degradation treatment, comparing the performance data of the treated product with the performance data of the product before treatment when the accelerated degradation treatment time is 48H, and screening out the product meeting the air tightness requirement; and when the accelerated degradation processing time is 1/90-1/110 of the calendar life of the product, comparing the processed product performance data with the product performance data before processing to verify the calendar life of the product, wherein the accelerated degradation processing temperature is 65-75 ℃, and the pressure is 0.15-0.25 MPa. The invention determines a pressure annunciator accelerated degradation test method which comprises test parameters such as temperature, pressure, time and the like, and through the test, the air tightness performance screening and the calendar life test verification of a product can be effectively carried out.
Description
Technical Field
The invention belongs to the instrument test technology, and particularly relates to a performance accelerated degradation test method of a pressure annunciator.
Background
The pressure annunciator is arranged at the root part of the helicopter blade and used for monitoring the change condition of the inflation pressure of the cavity of the blade girder. When the hollow blade girder appears penetrability crackle, gas leakage, atmospheric pressure in the cavity reduce, and the outward appearance of annunciator is become red dangerous signal by yellow safety signal, and the visual identification of being convenient for is reported an emergency and asked for help or increased vigilance.
The pressure annunciator is constructed as shown in fig. 1, and a helium-nitrogen mixture gas with about 1.5 atmospheres absolute is sealed in a reference cavity inside the annunciator as a reference pressure. When the pressure of the crossbeam is in a safety range, safety signals with alternate yellow and white are displayed on the annunciator, and the fact that the paddle can be used is indicated; if the longeron pressure drops below the minimum allowable pressure, the annunciator displays a danger signal between red and white. The process is that the bellows senses the pressure difference change to generate extension and contraction deformation and drive the indicating cap to move, so that red and yellow stripes marked on the indicating cap are displayed through transparent parts among white stripes of the glass cover (see figure 2).
The annunciator base is provided with a handle, the handle is pressed down under the state of normal work and displaying yellow-white safety signals, the passage of gas in the crossbeam to the annunciator is closed, residual gas in the corrugated pipe is discharged, and the annunciator displays red-white danger alarm signals for the function self-checking of the annunciator.
The main performance indexes of the annunciator are as follows:
a) initial working pressure: under the environment of 21 ℃, when the pressure is increased to 157kPa (absolute pressure), a safety signal is completely displayed, and no dangerous signal can appear; when the pressure is slowly reduced to 146kPa (absolute pressure), a danger signal is completely displayed, and a safety signal cannot appear;
b) pressing the manual button, wherein the annunciator is converted into a red danger signal within 30s, and the annunciator restores to display a yellow safety signal after the button is released;
c) the calendar life of the product is 10 years.
When the reference pressure in the annunciator is reduced due to leakage, the initial working pressure of the annunciator is reduced, and the hidden danger of leakage alarm is generated on the possible crack fault of the blade, so that the flight safety is endangered.
As shown in fig. 3, the reference chamber of the pressure annunciator is composed of a glass cover, a seal ring, a bellows, a base assembly, and the like. The two sealing links are static sealing structures with sealing ring end faces pressed and coated with sealing agents. The surface of the flange part for pressing the sealing ring has microscopic unevenness, the part of the dent which is not invaded by the sealing ring forms a gas leakage channel, and gas penetrates through the dent of the microscopic rough part on the surface of the contact surface to leak. The accumulation of trace leakage will lead to drift and degradation of product performance in long-term use.
The existing pressure annunciator product detection technologies, such as the detection devices and methods provided by CN109596565A and CN207866422U, cannot completely eradicate the hidden troubles in product performance detection. In addition, accelerated degradation testing techniques for other products, such as polyethylene pipe thermal oxidation accelerated aging test given in CN104266961A, although heat treatment is also adopted, are directed to natural aging, not pressure annunciator specific products. The pressure annunciator is a detection device, so that the pressure annunciator is sensitive to pressure change, and has high requirements on reliability and accuracy, and particularly, the reference cavity is of a closed structure, so that the prior art is difficult to realize accurate leak detection of the pressure annunciator, and an effective test verification method is lacked for the calendar life of a product.
Disclosure of Invention
The purpose of the invention is as follows: the accelerated degradation test method of the pressure annunciator based on the temperature and pressure effects is provided, and the air tightness screening of the product and the accurate verification of the calendar life of the product are effectively realized.
The technical scheme of the invention is as follows: a pressure annunciator accelerated degradation test method is characterized in that a pressure annunciator is placed in a sealed environment to be subjected to heating and pressurizing accelerated degradation treatment, the performance data of the treated product is compared with the performance data of the product before treatment, and the product is subjected to air tightness screening; and extracting a plurality of products for calendar life verification, and comparing the processed product performance data with the product performance data before processing when the accelerated degradation processing time is 1/90-1/110 of the calendar life of the product to realize the verification of the calendar life of the product, wherein the accelerated degradation processing temperature is 65-75 ℃, and the pressure is 0.15-0.25 MPa. The accelerated degradation treatment time for the hermetic screening is at least 48 hours.
The sealed environment is a high pressure tank.
The high-pressure tank is placed in a high-temperature test chamber.
The temperature was 70 ℃.
The pressure level is 0.2 MPa.
The accelerated degradation processing time for the product calendar life verification is 1/100 for the product calendar life.
The accelerated degradation processing time for the product calendar life verification is 0.1 year.
And the product performance data is an initial working pressure characteristic value.
The invention has the beneficial effects that: the invention has determined a pressure signal device accelerated degradation test method, including test parameters such as temperature, pressure, time, etc.; the invention determines a test statistical method of acceleration multiplying power; through the test, the air tightness performance screening and the calendar life test verification of the product can be effectively carried out.
Drawings
FIG. 1 is a schematic diagram of a pressure annunciator;
wherein, 1-a reference cavity, 2-a working cavity, 3-a sealing ring and 4-a manual inspection button;
FIG. 2 is a schematic diagram of two states of a pressure annunciator;
FIG. 3 is a schematic view of a pressure annunciator seal structure;
wherein, 3-sealing ring, 4-flange and 5-air leakage channel;
FIG. 4 is a schematic structural diagram of an accelerated degradation testing apparatus;
wherein, 6-high temperature test box, 7-high pressure tank, 8-pressure signal device;
FIG. 5 is a schematic diagram of performance curves before and after a pressure annunciator life test;
FIG. 6 is a graphical representation of the performance of a pressure annunciator screening test.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention applies high-temperature and positive-pressure combined environmental test stress to a product, namely a pressure annunciator, and can improve the leakage rate in the same time compared with normal temperature and normal pressure. Under the condition of applying high temperature, the difference of linear expansion coefficients of all parts in the sealing structure can cause the expansion of the leakage hole and the increase of the leakage rate, and the high temperature condition promotes the acceleration of molecular motion and accelerates the leakage; under the condition of applying positive pressure, the gas pressure difference on two sides of the leak hole is increased, so that the leak rate is increased. The two can realize the accelerated degradation of the performance of the test piece after being combined.
The accelerated degradation test method of the pressure annunciator based on the temperature and pressure effects comprises the steps of placing the pressure annunciator in a sealed environment, heating and pressurizing for accelerated degradation treatment, wherein the temperature is 65-75 ℃, the pressure is 0.15-0.25 MPa, the accelerated degradation treatment time is 1/90-1/110 of the total service life of a product, and comparing the treated product with product performance detection data before treatment to judge whether the calendar life of the product meets the expected requirements or not.
In one embodiment, as shown in FIG. 4, a plurality of pressure annunciators are placed in a high-pressure tank, and the high-pressure tank is placed in a high-temperature test chamber to form a sealed, heated and pressurized environment.
When the method is used for screening the air tightness of products:
testing the initial working pressure characteristic value of the product at normal temperature;
carrying out accelerated degradation treatment on the product, placing a pressure annunciator in a high-pressure tank, keeping the temperature at 70 ℃ and the pressure at 0.2MPa for 48 hours;
taking out the product, and testing the initial working pressure characteristic value of the product again after the product is restored to the normal temperature, wherein the initial working pressure characteristic value of the product refers to the minimum pressure value of the product during starting work and is a performance parameter of the product;
and calculating the difference value of the two initial working pressure characteristic values, and taking the preset qualified limit as a reference to obtain a test conclusion.
When the method is used for a product calendar life test:
testing the initial working pressure characteristic value of the product at normal temperature;
carrying out accelerated degradation treatment on the product, placing a pressure annunciator in a high-pressure tank, keeping the temperature at 70 ℃ and the pressure at 0.2MPa for 0.1 year;
taking out the product, and testing the initial working pressure characteristic value of the product again after the product is restored to the normal temperature;
and calculating the difference value of the two initial working pressure characteristic values, and taking the preset qualified limit as a reference to obtain a test conclusion.
The temperature is 70 ℃, the pressure is 0.2MPa for accelerated degradation treatment, the adopted temperature and pressure can effectively accelerate product degradation, product detection is realized, and meanwhile, the product can not be damaged. For this reason, the temperatures and pressures used are subject to a number of uncertain tests, preferably ultimately determined, depending on the performance of the pressure annunciator. Under the condition of the preferred parameters, a certain parameter range is allowed to be adjusted according to different models of the pressure annunciators. When the method is used for screening the annunciator process, a 48-hour test is carried out according to a preferred scheme, the time can enable the product leakage accumulation to reach a sufficient degree, the variation of the product performance can be effectively identified, and the product with the leakage hidden danger can be screened out, so that the time is allowed to be controllable, and the destructive damage to the product is basically avoided.
The acceleration rates of the above temperature and pressure test conditions were obtained by statistical analysis of a large number of test data. The average performance change rate under the normal working condition of the used piece is obtained by counting the working calendar time and the performance (leakage condition) change amount of the used piece, the average performance change rate is compared with the average performance change rate during the test piece acceleration test, the acceleration multiplying power of the optimized acceleration test scheme is 100 times, namely the working life of the pressure annunciator is generally 10 years, the acceleration processing time required during the calendar life verification is 0.1 year, and the test requirement can be reasonably met.
Please refer to fig. 5, which is a diagram illustrating performance curves before and after a lifetime test of the pressure annunciator. Curve 1 in FIG. 5 shows the product performance decay under normal conditions, with off-grade product below the curve. Curve 4 shows the effect of the preferred parameter of the present invention to accelerate degradation, and curves 2 and 3 show the effect of other parameter schemes to accelerate degradation. Compared with the curves 2 and 3, the slope of the curve 4 is larger, the test time is shortest, the acceleration effect is more obvious, and the verification of the calendar life of the product can be completed in a shorter time.
FIG. 6 is a partial enlargement of FIG. 5, from which it can be seen that the "lower screening limit" value obtained by curve 4 with the maximum slope is the largest in the same time (2 days), and can be effectively identified by the measurement system, meeting the product airtightness screening test requirements; the "lower screening limit" obtained from the remaining curves is significantly smaller and cannot be measured accurately. When the 'screening lower limit' value is taken to be the same, the screening time required by adopting the other curves is obviously longer than 2 days, and the efficiency is lower.
The foregoing is merely a detailed description of the embodiments of the present invention, and some of the conventional techniques are not detailed. The scope of the present invention is not limited thereto, and any changes or substitutions that can be easily made by those skilled in the art within the technical scope of the present invention will be covered by the scope of the present invention. The protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (9)
1. A pressure annunciator accelerated degradation test method is characterized in that a pressure annunciator is placed in a sealed environment to be subjected to heating and pressurizing accelerated degradation treatment, the performance data of the treated product is compared with the performance data of the product before treatment, and the product is subjected to air tightness screening; and extracting a plurality of products for calendar life verification, and comparing the processed product performance data with the product performance data before processing when the accelerated degradation processing time is 1/90-1/110 of the calendar life of the product to realize the verification of the calendar life of the product, wherein the accelerated degradation processing temperature is 65-75 ℃, and the pressure is 0.15-0.25 MPa.
2. The accelerated degradation testing method of a pressure annunciator of claim 1, wherein the accelerated degradation processing time for the hermeticity screening is at least 48 hours.
3. The method of claim 1, wherein the sealed environment is a high pressure tank.
4. The method of claim 2, wherein the high pressure tank is placed in a high temperature test chamber.
5. The method of claim 1, wherein the temperature is 70 ℃.
6. The method of claim 1, wherein the pressure level is 0.2 MPa.
7. The method of claim 1, wherein the accelerated degradation processing time for product calendar life verification is 1/100 for product calendar life.
8. The pressure annunciator accelerated degradation screening test method of claim 1, wherein the accelerated degradation processing time for the product calendar life validation is 0.1 year.
9. The method of claim 1, wherein the product performance data is an initial operating pressure characteristic value.
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| CN202010322300.7A CN111413027A (en) | 2020-04-22 | 2020-04-22 | Accelerated degradation test method for pressure annunciator |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN112595656A (en) * | 2020-12-09 | 2021-04-02 | 中国兵器工业第五九研究所 | Testing device and evaluation method for adaptability of explosive device long-storage environment for bomb |
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Application publication date: 20200714 |