Acoustics. Statistical methods for determining and verifying stated noise emission values of machinery and equipment. Part 4: Methods for stated values for batches of machines
Some standard content:
National Standard of the People's Republic of China
Acoustics-Statistical methods for determining and verifying stated noise emission values of machinery and equipment
Part 4: Methods for stated values for batches of machines GB/T 14573.493
This standard refers to and adopts the international standard IS07574/41985 "Statistical methods for determining and verifying stated noise emission values of machinery and equipment Part 4: Methods for stated values for batches of machines 1 Subject content and scope of application
This standard specifies the statistical methods for determining and verifying the noise emission values of machinery and equipment produced on a batch basis (such as nameplate values, market limits, negotiated values, and plate values).
This standard is applicable to determining and verifying the plate values of machinery and equipment produced on a batch basis. When the specified value of a batch of machines is not within the specified range, this standard does not deal with it. 2 Reference standards
G3102.7 Acoustic quantities and units
GB3947 Acoustic terminology
GB6378 Measuring oil sample inspection procedures and charts for defective product rate (applicable to continuous batch inspection) GB/T14573.1 Acoustics - Statistical method for determining and verifying the specified noise radiation value of machinery and equipment Part 1: Overview and definitions
3 General
3.1 The purpose of this standard to determine the plate value is to specify and limit the original method for the majority of machine noise in a batch of machines. The value is expressed in dB. 3.2 This standard is used as a principle for inspecting a continuous batch of samples when inspecting machine noise. Mainly based on the balance of risk, check whether the machine noise exceeds the specified upper limit. 3-3 The data for estimating risk points in this standard are based on: the medium quality level P1- with a noise value of 5% acceptance probability. 6.5%. The method for estimating the number of risk cases is given in Appendix A and Appendix B.
If the inspection results meet the requirements of this standard, it can be considered that the batch of machines is accepted according to the 95% acceptance probability. Note: The current situation of this standard assumes that the noise emission value of the machine is close to the normal distribution. When it deviates too far from the normal distribution, other solutions should be used according to the actual situation and clearly stated in the product standard. Response: When the limit value is not 1 but the mean value, the mean plus 1.5 can be used as the test value. This standard is used for inspection. Approved by the State Bureau of Technical Supervision on August 28, 1993 and implemented on March 1, 1994
GB/T 14573. 4-93
3.4 The machine noise radiation value data used in this standard should be the result of testing according to the noise measurement method specified for the product. This standard stipulates that a quasi-engineering grade or higher precision machine noise measurement method must be used. 4 Principles for determining the label value L by the quality inspector
4.1 When the label value of a certain type of machine of a certain specification in batch production needs to be determined, the quality inspector shall determine it according to the following procedures. 4.1.1 The sampling scale for determining the label value should not be less than the sample size during inspection. The label value of subsequent batches can be determined by testing each unit according to the output of the first consecutive batches, or the sample size can be determined by referring to the provisions of the inspection sample scale in Chapter 5. 4.1.2 The sound level L, (A-weighted sound power level) of the sample is measured according to the noise test method specified for the product. From L, the half mean value L and its standard deviation S of the sample can be obtained. 4. 1. 3 Refer to Appendix 13 and determine the label value according to the following formula based on the qualified rate of the selected product. When a,—am When, L,—.
When f+
In the formula: strict——the noise level of the batch of machines: —sample size
K——the coefficient of sample size determination·determined according to the table; Ur is the normal distribution quantity of the acceptance probability a (see Table 14), product——selected reference standard deviation:
——actual total standard deviation.
When P=95%, equations (1) and (2) are simplified. When, o,=0m,,=+1.5am
When n≠m, L—μ+l. 5a,+K(om—a.) (1)
(3)
reference standard deviation. The statistical value of the actual total standard deviation in the stable production can be used, or the comprehensive result of the uncertainty of the test method and the discreteness of the noise of the batch product can be used. -Generally used. ,一. The determination of this value should be clearly specified in the corresponding standards of this type of product. The batch mean is the mean of the noise level of consecutive batches of the product. When the batch of the product is too large to be measured one by one, the sampling mean 1 is used as the batch base mean.
4.2 In order to ensure the correctness of the label value, it is necessary to pay attention to random inspection at any time. In particular, when it is found that the factors affecting the machine noise are changing, or when the random inspection finds that the measurement base value changes greatly, the label value should be re-determined. 5 Inspection of the label value of batch machine noise
5.1 General
5.1.1 There are three sampling methods for checking the noise of batch machines, namely: single sampling, double sampling and sequential sampling. For a specific type of machine, only one of the three methods can be selected and specified in the corresponding standard of the product. If the noise radiation value of the machine is close to the normal distribution, the results obtained by one sampling method are the same. Generally speaking, the number of machines tested is smaller for double sampling or sequential sampling.
5.1.2. During the sampling inspection of the machine, the noise test method standard of the product shall be used for measurement, and the accuracy level of the test method shall be the highest engineering grade test method. When the measurement results are statistically calculated, the result value shall be retained to one decimal place. 5.1.3 The principle of sampling shall be consistent with that of Chapter 6. 5.2 Sampling inspection
5.2.1 Determine the sample size n according to the method given in Appendix A; or determine the sample size according to the principle of AQL=6.5 in accordance with the provisions of GB6378 sampling inspection standard: sampling can also be carried out in accordance with the prescribed standards of various product quality: the specific sampling scale shall be clearly specified in the corresponding standards of each product.
5.2.2 Determine according to the principle of 4.1.3
CB/T 14573.4-93
5.2.3 Measure the noise of the sampled points according to the noise test method and standard of the tested product, and calculate the average noise level of this sampling inspection according to formula (5)
Formula: I: sound level of the sampling station;
n: sample size,
5. 2. 4 Judgment value A is calculated according to formula (6). 4
In the formula: K——Number of receiving bands:
In the formula:
is the number of standard normal distribution points corresponding to 1-α, and is the prime number of standard normal distribution points corresponding to 1-α. When 1-P,-.=93.5%,1-
is out: the acceptance constant K can be found according to Table 1,
1. 511,01-=1. 645.
The acceptance constant K of different sample sizes
5.2.5*LA. The inspection result is that the label value is positive. When LA, it is considered that the label value is denied. 5.3 Sampling inspection
5.3.1 According to the principle of 5.2.1, randomly select a sample of cup size. 5.3.2 According to 5.2.3 tea, obtain..
5.3.3 According to the acceptance constants K, and K, given in Table 2, calculate the judgment value: 4
(6)
GB/T 14573. 4—93
The acceptance constant corresponding to the random sampling
5.3.4 Make an acceptability judgment according to the following rules: Draw
— 0. 203
Equivalent to a single sampling
5. 3.4. 1 When L≤A, the inspection result is that the label value is affirmed; when L→B, it is considered that the label value is denied. When A5.3.4.2
Then calculate the second value to be determined by the secondary sampling according to formula (10): = IKadm
If I,≤c, then the label value is determined to be affirmative. If I→c, then the label value is determined to be negative. 5.4 Sequential sampling inspection
5.4.1 According to the principle of Article 5.2.1, firstly carry out random sampling with the sample size of equivalent secondary sampling. Determine the sound level I of each product according to the corresponding standard, and then sum it according to formula (11):
Where: b-
Acceptance constant (determined according to Table 3).
5.4.2 The inspection results are determined according to the following principles
5.4.2.1 If S,a, then the label value is determined to be negative: If S.>, Jing, then the label value is determined to be negative:
If α<5,0, then the noise label value is negated. Note: The acceptance constants a., and in the judgment rule are given in Table 3. (11)
Principles and contents of the note
—l.sh2am
--2.0000m.
—2. 1890..
-2.680am.
—2.823g.
GB/T 14573.4 -- 93
Acceptance constant corresponding to sequential sampling
L. 0. 351d.
L—0, 564n
L—(, 692dm
Ie.C.8420
1,—.8920m
1--0.9940m
When formulating the noise label value and inspection plan for a certain type of machine, the necessary content should be provided according to the following principles. 6.1 When formulating the qualification documents for this batch of products, the following principles should be observed: finality of the inspection;
relative size of the user's risk;
uncertainty of the measurement result
6.2 When formulating various professional standards, the following issues should be explained in detail. How to use GB/T 14573.4 The professional standard is formulated based on the following: h.
Apply the definition of machine type in the test specification of this type of machine; each special test specification for a specific type of machine: equivalent single sampling
If there is no special test specification for this type of machine, the installation conditions, load conditions and operating requirements of the machine during the test should be specified when selecting the standard;
The sampling method used for this type of machine (single, double and sequential sampling) and the corresponding sample size (n, n, or nn); Determination of reference standard deviation;
The reference sampling characteristic curve, which should be consistent with this clause and Appendix A. A1 General
GB/T 14573. 493
Appendix A
Examples of sampling characteristics and primary, secondary and sequential sampling (Supplement)
This appendix explains the meaning of sampling characteristics and gives guidance on the use of sampling characteristics. These sampling characteristics are used to select the appropriate sample size for checking specific machines. This sample size should be given in the sampling method for developing professional label specifications.
A2 Sampling characteristics (OCs)
The K value given in Table 1 is based on the manufacturer's risk point 1. When the ratio of the noise auxiliary radiation value to the pass value in the batch of machines is equal to -6.5%, the probability that this batch of machines will be wrongly rejected is 5* (at the manufacturer's risk point on the sampling characteristics curve). Since, in addition to the fixed risk point of the manufacturer, the sample size has been specified in the special marking rules for each machine type, the time curve is also determined. Figure 1 shows the corresponding sample size and the use curve. 100
Pl-a-6.5 years
Manufacturer risk point
User risk point
Postal state The proportion of the value under the label P
Detection characteristic curve of the second, second and sequential sampling 80
100 (%)
Note that the curve in Figure A1 is derived from the following formula: CB/T 14573. 4-93
m=u .-k) vn
This formula is a general form of formula (7) in 5.2, based on the sampling characteristic curves (derived for the single oil sampling) for the equivalent sub-sampling and sequential sampling scheme in accordance with 5.3 and 5.4. These C curves are essentially interlaced with the OC curves for the single sampling. A3 Guidelines for the selection of appropriate sample sizes
In accordance with clauses 5 and 6, for each specific machine type, the sample size n (together with a.) shall be specified in the product-specific marking plan. Determine how to choose the calculable assumed label value L. -- α. When L. is the label value, there is such a large proportion that the noise radiation estimate is exceeded that there is only a low acceptance probability of 10% and less than the corresponding 95% (the production risk is 5%). The smaller A1 is, the larger the sample size is, and the smaller the proportion of noise radiation values that exceed the risk of the user is (value, see Table 34). AL - -- ( .-)
= (1. 645 + 1. 282)
For a given A1. The sample size is determined by the rounded integer obtained from formula (A2). 2.93g.
This relationship is given by the curve in Figure A2,
Example: Given = 2dB, A—3d
Therefore, the relationship between a
L and the sample size n
A4 Examples of single sampling, double sampling and sequential sampling inspections A4.1 Example of single sampling inspection (see 5.2) This type of inspection method is formulated for batch machines of a specific machine type. 4
Sample * size n
(A2)
Plate value
From Table 1:
Measured value
CB/T 14573.4—93
L,=87 dB
A =-L. Kau --87-(0.564X2) -\ 85.9 dT3L, -84.6 dB
L—85.4 dB
L - 85.67 tB
The result of checking the batch of machines, the label is backed by A4.2 Example of double sampling inspection (see 5.3) Here is the inspection method formulated for a specific type of batch of machines, a..=2d
ng=3.(n=5)
The label value
Table 2 shows:
The measured value of the first sample
When 4
Take the :th sample with the smallest n. -3. The measured value of the first sample
The result of checking the batch, the label value is negated. A4.3 Example of sequential sampling inspection (Case 5.4) L,= dB
,—1. 649bZxz.net
K, 20. 130
Ki- 0.774
A=I. —K,bn=87-(1. G49×2)=83. 70 dRB=L,K,om =87+(0. 130X2) =87. 26 dB(m=2)
L,=85. 3 dB
L,—86. 7 dB
1...86. 0R
L,=84. 4 d13
I,--88. 0 d11
L,=83.6 dB
ZL,-85.6 dB
= L.=-K.id.=87-(0.774×2) =85.452 dBHere is the inspection method for the batch waste machine of its body type..2dR
label value
From Table 3, we get:
I.. --S7 dR(IwA--87 dR)
2—1.552×..
First measurement value (#=1)
Conclusion, due to as(See Figure B1) Three batches of vacuum cleaners manufactured by different manufacturers. The distribution function of their noise emission values is plotted on probability paper according to the increasing frequency curve. The noise emission values of these three batches of machines are equal (u=84dB), while their total standard deviation can have three different results: 1dB, 2dB and 4dB. The specified reference standard is 2dB. Reduce the sample size specified for batch inspection of this type of machine = 3△13.4dB, according to Section A3), and the sampling characteristic curve can be applied>《From Figure B1, for =3). This sampling characteristic curve is only valid at 0, =0m. On the probability paper, the corresponding points for the corresponding sound levels of different proportions can be found on the sampling characteristic curve of Figure B1. 1 - ±= 95 % r
86· H5.5
Le1 a-95.>
SAI B9
9 .98.6
CB/T 14573.4—93
Sampling characteristic curve
80005 401 0
Protection +- 6. 5%
Figure 310./0 Sampling characteristic curve variation diagram
0.1 0.05(%
There is no provision for the quarterly standard deviation (main), and the total standard deviation can be obtained from the manufacturer.
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