阅读说明：本技术 一种基于冷热交变加速法的热量表寿命评价方法 (Calorimeter life evaluation method based on cold-hot alternating acceleration method ) 是由 张柯 王梅 朱永宏 路兴杰 谷田平 周文辉 段云 陈飞 许雪琼 冯鑫 樊家成 于 2020-06-18 设计创作，主要内容包括：本发明涉及热量表寿命评价领域,具体说是一种基于冷热交变加速法的热量表寿命评价方法,该热量表寿命评价方法,采用2400次+2400次+1600次+1600次+800次+…的冷热交变加速试验方式,分别代表3年+3年+2年+2年+1年+…热量表寿命的耐久周期,配合被试热量表的故障率,对不同批次、生产厂家的热量表产品做更为精确的寿命预估,并且使热量表寿命评估更接近真实寿命,能更好的为企业改进仪表设计或提高工艺水平提供参考。(The invention relates to the field of calorimeter life evaluation, in particular to a calorimeter life evaluation method based on a cold-hot alternating acceleration method, which adopts a cold-hot alternating acceleration test mode of 2400 times +1600 times +800 times + … to respectively represent the durability periods of the calorimeter life of 3 years +2 years +1 year + …, and more accurate life prediction is carried out on calorimeter products of different batches and manufacturers by matching the fault rate of a tested calorimeter, so that the calorimeter life estimation is closer to the real life, and references can be better provided for enterprise improved instrument design or improved process level.)

1. A calorimeter life evaluation method based on a cold-hot alternating acceleration method is characterized by comprising the following steps: the method comprises the following steps:

a. randomly extracting 12 tested sample tables from heat meters produced by a certain batch of enterprises;

b. measuring error tests of three flow points of qi, 0.1qs and qs are carried out on 12 randomly-extracted tested sample tables, and indicating value errors of each flow point of each tested sample table are recorded;

c. 2400 times of cold-hot alternating accelerated durability tests are carried out on the surface of a tested sample, and the test method is the same as European standard EN1434-4: 2015;

d. performance evaluation: after 2400 times of cold-hot alternating accelerated durability test, judging that the test is unqualified when the following conditions occur;

(1) and appearance: the display is not clear, broken and not displayed;

(2) and the sealing performance of the flow sensor: leakage, seepage or damage during testing or indicating value detection;

performing a metering error test on the residual sample table, and judging that the sample table is unqualified when the following conditions occur;

(1) MPE with sample representation value error exceeding 2 times;

(2) the variation of the error before and after the test exceeds plus or minus 1.5 times MPE;

in the stage of test, the life of the unqualified sample is estimated to be 3 years;

e. after the 2400 times cold-hot alternating accelerated durability test, rejecting unqualified samples, and performing the 2400 times cold-hot alternating accelerated durability test on the other qualified test tables;

after the 2400 times of cold-hot alternating accelerated durability test, evaluating the sample to be tested again, wherein the evaluation method is the same as the step d;

in the stage of test, the life of the unqualified sample is estimated to be 6 years;

f. after 2400 cold-hot alternating accelerated durability tests are carried out for the second time, unqualified samples are removed, and 1600 cold-hot alternating accelerated durability tests are carried out on the other qualified test tables;

after the 1600 times of cold-hot alternation accelerated durability test, the sample to be tested is evaluated again, and the evaluation method is the same as the step d;

in the stage of test, the life of the unqualified sample is estimated to be 8 years;

g. after the cold-hot alternating accelerated durability test for 1600 times, unqualified samples are removed, and the cold-hot alternating accelerated durability test for 1600 times is carried out on the rest qualified test tables;

after the two 1600 times of cold-hot alternation accelerated durability tests, the sample to be tested is evaluated again, and the evaluation method is the same as the step d;

in the stage of test, the life of the unqualified sample is estimated to be 10 years;

h. after the secondary 1600-time cold-hot alternating accelerated durability test, unqualified samples are removed, and 800-time cold-hot alternating accelerated durability test is carried out on the rest qualified test tables;

after the 800 times of cold-hot alternation accelerated durability test, the sample to be tested is evaluated again, and the evaluation method is the same as the step d;

in the stage of test, the life of the unqualified sample is estimated to be 11 years;

i. and h, if a sample is qualified, continuously repeating the step i each time to perform the 800 times of cold-hot alternating accelerated durability test, evaluating the sample to be tested, accumulating the service life duration each time by one year until the last sample to be tested is unqualified, recording the service life duration, and stopping the test.

j. Evaluating the life characteristics: estimating according to the life time of all tested samples: has t₁，t₂，...t₁₂Substituting the following formula:

the degree of dispersion is expressed as the sum of squared deviations:

the failure rule of the calorimeter product follows exponential distribution, and the overall average service life of the batch calorimeter is mu:

the deviation of the total service life of the batch calorimeter is sigma²：

Wherein: f (t) ═ λ e^-λt，

2. The calorimeter life evaluation method based on the alternating cold and hot acceleration method according to claim 1, wherein: the measurement error test refers to a test and calculation test of GB/T32224-201 calorimeter measurement accuracy.

3. The calorimeter life evaluation method based on the alternating cold and hot acceleration method according to claim 1, wherein: the MPE refers to a maximum allowable error.

Technical Field

The invention relates to the field of calorimeter service life evaluation, in particular to a calorimeter service life evaluation method based on a cold-hot alternating acceleration method.

Background

With the continuous development of heat supply reform, heat metering is deepened gradually all over the country, the installation and the use of the heat meter in the heat supply metering field are increased year by year, and accordingly the heat meter runs reliably for a long time, namely the durability is emphasized and concerned. The durability test of the heat meter simulates the service life of a product through accelerated wear of the heat meter so as to check and improve the product quality and ensure long-term stable and reliable operation of the heat meter in an installation period. In recent years, many local heat supply companies in China require heat meter production enterprises to provide a quality guarantee period of more than 5 years, individual regions even require that the service life of the heat meters reaches 8-10 years, but the quality of heat meter products in the market is poor, and heat supply departments and heat meter users can reliably maintain the performance and realize the functions of the selected heat meter products within a long service life and are not known.

Durability (durabilty) is one of the three major elements of product reliability, reflecting the useful life of a product in its normal functioning. In terms of the definition of the durability test, the durability test of the heat meter aims at achieving accelerated aging, is a test for measuring the service life of a heat meter product under specified use and maintenance conditions and predicting or verifying weak links and dangerous parts of a structure, and can calculate the service life of the heat meter product.

The related technical standard of the calorimeter in China has low requirement on the durability test, is a 300h durability test, and has larger difference with 4000 times of cold and heat shock accelerated durability tests proposed by European standard EN 1434-2007. Since 2014, the durability test project group of the working committee of calorimeters of the China metering association organizes the national durability test of the calorimeters by referring to the related requirements of European standard EN1434-2007, the overall qualification rate of the 2014 test is 88.5%, and the overall qualification rate of the 2015 test is 93.5%, and the results prove that the long-term use stability of most domestic products participating in enterprises meets the requirements of the European standard, the long-term operation requirements of the calorimeters for at least 5 years can be met, but the specific durability period of the calorimeters is not further estimated.

In the conventional durability test of the calorimeter, samples are all sent by a production enterprise instead of being sampled, and the test result only represents the sent samples, so that the service life characteristics of batch products cannot be evaluated and calculated. In the past test, only unqualified samples after the test are screened out, but no life span estimation is carried out on the unqualified samples and the qualified samples, the life span of the qualified samples is only evaluated for more than 5 years, but no further estimation is carried out on the specific service life of the qualified samples, and the life span of a sampled batch of products cannot be estimated. Therefore, enterprises cannot better know the service life characteristics, failure rules, failure rate, average service life and various failure modes which may occur in the service life test process, and cannot better provide reference for the enterprises to improve the design of instruments or improve the process level. Therefore, how to overcome the above technical problems and disadvantages is a problem to be solved.

Disclosure of Invention

The invention aims to overcome the defects described in the background technology, so that the method for evaluating the service life of the heat meter based on the cold-hot alternating acceleration method is realized, the evaluation method is matched with the fault rate of the heat meter to be tested, more accurate service life estimation is carried out on heat meter products of different batches and manufacturers, the service life evaluation of the heat meter is closer to the real service life, and references can be better provided for enterprises to improve the design of instruments or improve the process level.

In order to achieve the purpose, the technical scheme of the invention is as follows: a calorimeter life evaluation method based on a cold-hot alternating acceleration method comprises the following steps:

a. randomly extracting 12 tested sample tables from heat meters produced by a certain batch of enterprises;

b. measuring error tests of three flow points of qi, 0.1qs and qs are carried out on 12 randomly-extracted tested sample tables, and indicating value errors of each flow point of each tested sample table are recorded;

c. 2400 times of cold-hot alternating accelerated durability tests are carried out on the surface of a tested sample, and the test method is the same as European standard EN1434-4: 2015;

d. performance evaluation: after 2400 times of cold-hot alternating accelerated durability test, judging that the test is unqualified when the following conditions occur;

(1) and appearance: the display is not clear, broken and not displayed;

(2) and the sealing performance of the flow sensor: leakage, seepage or damage during testing or indicating value detection;

performing a metering error test on the residual sample table, and judging that the sample table is unqualified when the following conditions occur;

(1) MPE with sample representation value error exceeding 2 times;

(2) the variation of the error before and after the test exceeds plus or minus 1.5 times MPE;

in the stage of test, the life of the unqualified sample is estimated to be 3 years;

e. after the 2400 times cold-hot alternating accelerated durability test, rejecting unqualified samples, and performing the 2400 times cold-hot alternating accelerated durability test on the other qualified test tables;

after the 2400 times of cold-hot alternating accelerated durability test, evaluating the sample to be tested again, wherein the evaluation method is the same as the step d;

in the stage of test, the life of the unqualified sample is estimated to be 6 years;

f. after 2400 cold-hot alternating accelerated durability tests are carried out for the second time, unqualified samples are removed, and 1600 cold-hot alternating accelerated durability tests are carried out on the other qualified test tables;

after the 1600 times of cold-hot alternation accelerated durability test, the sample to be tested is evaluated again, and the evaluation method is the same as the step d;

in the stage of test, the life of the unqualified sample is estimated to be 8 years;

g. after the cold-hot alternating accelerated durability test for 1600 times, unqualified samples are removed, and the cold-hot alternating accelerated durability test for 1600 times is carried out on the rest qualified test tables;

after the two 1600 times of cold-hot alternation accelerated durability tests, the sample to be tested is evaluated again, and the evaluation method is the same as the step d;

in the stage of test, the life of the unqualified sample is estimated to be 10 years;

h. after the secondary 1600-time cold-hot alternating accelerated durability test, unqualified samples are removed, and 800-time cold-hot alternating accelerated durability test is carried out on the rest qualified test tables;

after the 800 times of cold-hot alternation accelerated durability test, the sample to be tested is evaluated again, and the evaluation method is the same as the step d;

in the stage of test, the life of the unqualified sample is estimated to be 11 years;

i. and h, if a sample is qualified, continuously repeating the step i each time to perform the 800 times of cold-hot alternating accelerated durability test, evaluating the sample to be tested, accumulating the service life duration each time by one year until the last sample to be tested is unqualified, recording the service life duration, and stopping the test.

j. Evaluating the life characteristics: estimating according to the life time of all tested samples: has t₁，t₂，...t₁₂Substituting the following formula:

the degree of dispersion is expressed as the sum of squared deviations:

the failure rule of the calorimeter product follows exponential distribution, and the overall average service life of the batch calorimeter is mu:

μ＝∫₀ ^∞tf(t)dt

the deviation of the total service life of the batch calorimeter is sigma²：

σ²＝∫₀ ^∞(t-μ)²f(t)dt＝∫₀ ^∞t²f(t)dt-μ²

Wherein: f (t) ═ λ e^-λt,

Further, the metering error test refers to a test and calculation test of the metering accuracy of the GB/T32224-201 calorimeter.

Further, the MPE refers to a maximum allowable error.

The method for evaluating the service life of the heat meter based on the cold-hot alternating acceleration method has the beneficial effects that:

the method for evaluating the service life of the heat meter based on the cold-hot alternating acceleration method adopts the cold-hot alternating acceleration test mode of 2400 times +1600 times +800 times + … to respectively represent the endurance cycles of the service life of the heat meter of 3 years +2 years +1 year + …, and performs more accurate life estimation on heat meter products of different batches and manufacturers by matching with the fault rate of the tested heat meter, so that the service life estimation of the heat meter is closer to the real life, and compared with the method for evaluating the service life of the heat meter by only evaluating the service life of an acceptable sample by European standard for more than 5 years, the method for evaluating the service life of the heat meter has the advantages that the service life estimation of the heat meter is more accurately subdivided, and the reference can be better provided for improving the design of the meter or improving the process level of.

Drawings

FIG. 1 is a schematic temperature profile of 2400 cycles of cold-hot alternation accelerated durability tests.

Detailed Description

The method for evaluating the service life of a heat meter based on a cold-hot alternating acceleration method according to the present invention will be described in more detail by specific embodiments with reference to the accompanying drawings.

In the description of the present invention, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention.

Referring to fig. 1, the method for evaluating the service life of a heat meter based on a cold-hot alternating acceleration method of the embodiment includes the following steps:

a. randomly extracting 12 tested sample tables from heat meters produced by a certain batch of enterprises;

b. measuring error tests of three flow points of qi, 0.1qs and qs are carried out on 12 randomly-extracted tested sample tables, and indicating value errors of each flow point of each tested sample table are recorded; the metering error test refers to a test and calculation test of GB/T32224-201-calorimeter metering accuracy;

c. 2400 times of cold-hot alternating accelerated durability tests are carried out on the surface of a tested sample, and the test method is the same as European standard EN1434-4: 2015;

d. performance evaluation: after 2400 times of cold-hot alternating accelerated durability test, judging that the test is unqualified when the following conditions occur;

(1) and appearance: the display is not clear, broken and not displayed;

(2) and the sealing performance of the flow sensor: leakage, seepage or damage during testing or indicating value detection;

performing a metering error test on the residual sample table, and judging that the sample table is unqualified when the following conditions occur;

(1) MPE with sample representation value error exceeding 2 times; the MPE refers to a maximum allowable error;

(2) the variation of the error before and after the test exceeds plus or minus 1.5 times MPE;

in the stage of test, the life of the unqualified sample is estimated to be 3 years;

e. after the 2400 times cold-hot alternating accelerated durability test, rejecting unqualified samples, and performing the 2400 times cold-hot alternating accelerated durability test on the other qualified test tables;

after the 2400 times of cold-hot alternating accelerated durability test, evaluating the sample to be tested again, wherein the evaluation method is the same as the step d;

in the stage of test, the life of the unqualified sample is estimated to be 6 years;

f. after 2400 cold-hot alternating accelerated durability tests are carried out for the second time, unqualified samples are removed, and 1600 cold-hot alternating accelerated durability tests are carried out on the other qualified test tables;

after the 1600 times of cold-hot alternation accelerated durability test, the sample to be tested is evaluated again, and the evaluation method is the same as the step d;

in the stage of test, the life of the unqualified sample is estimated to be 8 years;

g. after the cold-hot alternating accelerated durability test for 1600 times, unqualified samples are removed, and the cold-hot alternating accelerated durability test for 1600 times is carried out on the rest qualified test tables;

after the two 1600 times of cold-hot alternation accelerated durability tests, the sample to be tested is evaluated again, and the evaluation method is the same as the step d;

in the stage of test, the life of the unqualified sample is estimated to be 10 years;

h. after the secondary 1600-time cold-hot alternating accelerated durability test, unqualified samples are removed, and 800-time cold-hot alternating accelerated durability test is carried out on the rest qualified test tables;

after the 800 times of cold-hot alternation accelerated durability test, the sample to be tested is evaluated again, and the evaluation method is the same as the step d;

in the stage of test, the life of the unqualified sample is estimated to be 11 years;

i. and h, if a sample is qualified, continuously repeating the step i each time to perform the 800 times of cold-hot alternating accelerated durability test, evaluating the sample to be tested, accumulating the service life duration each time by one year until the last sample to be tested is unqualified, recording the service life duration, and stopping the test.

j. Evaluating the life characteristics: estimating according to the life time of all tested samples: has t₁，t₂，...t₁₂Substituting the following formula:

the degree of dispersion is expressed as the sum of squared deviations:

the failure rule of the calorimeter product follows exponential distribution, and the overall average service life of the batch calorimeter is mu:

μ＝∫₀ ^∞tf(t)dt

the deviation of the total service life of the batch calorimeter is sigma²：

σ²＝∫₀ ^∞(t-μ)²f(t)dt＝∫₀ ^∞t²f(t)dt-μ²

Wherein: f (t) ═ λ e^-λt,

Unless defined otherwise, technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs. The use of the terms "a" or "an" and the like in the description and in the claims of this application do not necessarily denote a limitation of quantity. The word "comprising" or "comprises", and the like, means that the element or item listed before the word covers the element or item listed after the word and its equivalents, but does not exclude other elements or items. The terms "connected" or "coupled" and the like are not restricted to physical or mechanical connections, but may include electrical connections, whether direct or indirect.

Exemplary embodiments of the present invention have been described in detail with reference to the preferred embodiments, however, it will be understood by those skilled in the art that various changes and modifications may be made to the specific embodiments described above, and various combinations of the technical features and structures proposed by the present invention may be made without departing from the concept of the present invention.