GB/T 4980-2003 Determination of noise level of positive displacement compressors
Some standard content:
This standard replaces G1/T49:1985 Simple method for determination of sound power level of integrated compressor G/T498-2013/4380-1685/70221986. The main changes are as follows: F-appropriate adjustment of the measurement environment; K-specific method for determination of the sound power level of compressor units. This standard is permanent in Appendix A and Appendix C, and the information recorded in Appendix 1 and Appendix 5 of this standard is longer than that of the China Association of Industry and Information Technology. This standard contains the simplified method for the measurement of sound power level of compressor units. The technical committee of this standard will issue this standard from the Institute of Appropriate Units of Research and Development of Lifting and Reducing Flow. The main drafters of this standard are Zhang Fang, Jie Xiang, and Lin Liaoliang. This standard replaces the standards: G849801995H/02--1536
1 Scope
Determination of noise of volumetric compressors
CB/T 4980—200.3
6 The standard specifies the method for determining the noise of volumetric compressors. This standard mainly stipulates the "group method" for measuring the noise rate level. The attached method is to determine the noise level of the product. The standard is applicable to the following types of passenger aircraft including the compressor unit (hereinafter referred to as the compressor unit 1, the normative reference to the establishment of the document
the following small policy clauses are used in the standard and become the terms of the standard. The state of the document is busy with the material and all subsequent changes (including the small period of change) are not applicable to the ten-rate standard. However, the standard is achieved. The parties to the agreement shall use the revised version of this document. All references to the previous issue of the document shall apply to the latest version of this standard. 3(2.1993)3:1992)/T3221098 Frequency Division Multiplexing Filter eqIF:1260:155G15/T37851963 Electric, Acoustic Energy and Test Methods GB317-95 Acoustic Terms and Definitions GB/T347-[9 and GB3.-1993 Unspecified terms and definitions, unit names and symbols shall not apply to this standard.
4 Requirements
4.7 Measuring instruments
4.1.1 Overview
The measuring instruments shall be type 1 or above sound meters specified in R/T3785:983, and other test instruments of equivalent performance. The frequency conversion instrument shall comply with the provisions of 6B/T24.-1998. 4.1.2 Calibration
Before each measurement, the measuring instrument shall be calibrated with a sound level meter with a precision better than 1C.5. If the two calibration values exceed the range of 1B, the measurement channel shall be invalid.
4.2 Measurement, determination and error
4.2.1 Measurement environment
The sound field generated by the measuring instrument on the opposite plane shall be within the limit and the sound source shall be solid and reliable. The environment suitable for this standard is: 1) a test room with two reflecting planes on which the sound field is heard, such as a semi-anechoic room; 2) an outdoor venue with a reflective object on the reflecting plane; 3) a room with a reflective object on the reflecting plane at least 31 meters away from the transmitter; 4) a room with a reflective object on the reflecting plane at least 31 meters away from the transmitter; 5) a room with a reflective object on the reflecting plane at least 31 meters away from the transmitter; 6) a room with a reflective object on the reflecting plane at least 31 meters away from the transmitter; 7) a room with a reflective object on the reflecting plane at least 31 meters away from the transmitter; 8) a room with a reflective object on the reflecting plane at least 31 meters away from the transmitter; 9) a room with a reflective object on the reflecting plane at least 31 meters away from the transmitter; 10) a room with a reflective object on the reflecting plane at least 31 meters away from the transmitter; 11) a room with a reflective object on the reflecting plane at least 31 meters away from the transmitter; 12) a room with a reflective object on the reflecting plane at least 31 meters away from the transmitter; 13) a room with a reflective object on the reflecting plane at least 31 meters away from the transmitter; 14) a room with a reflective object on the reflecting plane at least 31 meters away from the transmitter; 15) a room with a reflective object on the reflecting plane at least 31 meters away from the transmitter; 16) a room with a reflective object on the reflecting plane at least 31 meters away from the transmitter; 17) a room with a reflective object on the reflecting plane at least 31 meters away from the transmitter; 18) a room with a reflective object on the reflecting plane at least 31 meters away from the transmitter; 19) a room with a reflective object on the reflecting plane at least 31 meters away from the transmitter; 19) a room with a reflective object on the reflecting plane at least 31 meters away from 4.2.2 Quantities to be determined 1) A-weighted sound power level: GR/[4980--2003] h) Select and measure ten times the frequency of the sound power level within the range of 12x~100uEz. 4.2.3 Display error When measuring according to this standard, the standard deviation of the A-weighted sound power level shall not exceed 2 times the standard deviation of the sound power level! The value of the standard.
model center frequency H
253--500
1 000--4 0c:
standard slow deviation: dR
three, the standard table refers to the use of various factors or theft of the standard to ensure the benefit, but also includes the service quality of the reduction of the installation and operation of the state caused by the serious harm of the sub-chemical
4.3 compressor unit installation and operation
4.3.1 compressor unit installation
4. 3. 1.1 The delivery of the compression unit shall comply with its new release standards. If there is no clear standard, it shall comply with the requirements of the instructions and technical documents.
43.1.2 For the compressed air, the equipment should be suitable for the environment where the compressed air is not suitable for the user. The appropriate measures should be taken to ensure that the environment does not affect the sound level. The appropriate measures should be taken to absorb the material and lead the difficult air to the outside of the test environment or through some channels.
4.3.2 The operation of the compression unit
The unit should be continuously tested under rated working conditions. After it reaches a stable state, it should be tested. If necessary, it can also be tested under other working conditions (including media) of various related industries. The test report shall state 4.4 Reference body and test surface
Z.4.1 Reference body
4, 4.1.1 "To determine the test The position of the surface and the position of the sensor should be taken as the most central distance between the three surfaces of the compressor unit (see Figures 1 to 9 in the Appendix) and used as the reference body: the base body is called the base body. For small protruding parts of the compressor unit, such as the pull rod and the main pipe, these non-essential parts are not considered, and the air discharge installed directly on the suction port is used as the reference body.
4.4.1.2 For example, the compressor (see Figure 7-Figure) The reference body size can be determined by the most important parts and the most important parts of the product.
4.4.2 Measuring surface
The measuring surface is a rectangular hexahedron with the same surface as the measuring standard (excluding the anti-plane) on the reflecting plane. Each surface is parallel to the corresponding surface of the base and is 1m apart. The main surface area is calculated as follows: S -. (at ! be I αc)
Wherein:
, unit is meter (m):
are the length and width of the measurement surface respectively, and
c is the measurement surface. The unit is * (m): 5 Determination method
5.1 Sound pressure level at measuring point
The sound pressure level of the large and small units of the butyl body should be measured at a moving point, and then the background noise should be measured at each 2
marked point. The sound pressure level of the supply medicine is measured according to Table 2. The sound pressure level of the unit obtained by
in Table 2 is consistent with the background noise production pressure level. 5.1.2 Wind inspection
R0/T 4980-2003
The unit is decibel (B)
The most effective measurement is made from the measured sound level
Use a hood outdoors in the early morning, with a daytime wind speed of less than 6m/equivalent to level 4 wind) 5.1.3 Measurement point locations
5. 1, 3.1 Overview
All common points (i.e. microphone layout points) should be located vertically or on the surface as determined in 4.4.2. The points are divided into basic measuring points and additional measuring points (see Figure 1). The measuring points are: O--main body A.--sea point 2. Surface 1. Reference body, monitoring surface and microphone position 5.1.3.2 Basic measuring points The basic measuring points are 5.1.3.2 Basic measuring points The basic measuring points are 1. The point is located in the middle of each side, and the height from the reflector is half of the base position, not less than 1.151. The 5th point is at the tip of the second side, and the 6th to 9th points are at the four corners of the measuring surface. If the exhaust pipe is 0.5m away, the flow stimulation point should be cancelled. 1.3.3 Additional measuring points
5.1.3.3.1 The following additional measuring points should be added. The maximum value of the A-weighted sound power level obtained by the basic measuring points is greater than that of any one of the two measuring points (B). 5.1.3.3.2 The number of additional measuring points on the measuring surface increases from 5 to 17. Among them, 19-13 points are located on the measuring surface of the reflection surface. The height from the reflection surface to the midpoint of the four sides of the measuring surface before the reflection surface is 14-7 points. 5.1.3.4 Reduction in the number of points
If the measurement proves that the difference between the A-weighted sound power level determined by the original measuring points and the A-weighted sound power level determined by the proposed points (-points) is not greater than 1T, then the number of measuring points can be reduced to 5. 5. 1.4 Measurement
The sound source under test should be verified by the slow\time weighted characteristic measurement of the product level meter. When the product level meter fluctuation is not large, take the average of the maximum and minimum levels at the measurement point. The measurement period is at least 250H, and the center frequency is the signal frequency. The current measurement period is , when the level fluctuation is greater than:
) an analog instrument or a digital integrating level meter with a longer time value should be used for testing:) For non-stable limit sound with weekly changes, use a slow\time weighted level meter, record the positive level and duration in each period, and calculate the half-mean value of one period. 5.1.5 Correction of measurement environment
When the measurement environment contains unnecessary reflectors, the measurement results must be corrected to determine the final value of the environment. 5.3
5.2 Calculation of average surface pressure level and acoustic frequency level 5.2.1 Calculation of surface sound pressure level
The average surface sound pressure level is calculated using the following formula: L.0s
Wherein,
is. —-Measure the surface average A-weighted sound pressure level times the standard production pressure level, unit price is decibel (d> (principle 25×Iu-Fa): According to 5.1.1, the A-weighted sound pressure level or the frequency sound pressure level at the point of the film can be determined in decibels. The value is 20-Pa
N-total number of points.
5.2.2 Calculation of sound power level
Sound power level 1 is calculated as follows:
Lw:-L,-K)-10 JgtS/Sn
L—-weighted sound power level or times the frequency level, unit price (d3) is 1X13! W); 3
--measurement level and A-weighted sound pressure level or octave sound pressure level, in decibels ((reference 2c×10-2); K--ambient correction value, in decibels (see 3.1) S--measurement surface area, in square meters) S. The base value is 1m
5.3 Determination of environmental positive value K
5.3.1 General
The environmental positive value K can be determined by a standard sound source. According to the environmental conditions, the value K can be increased by 2dB. 5.3.2 Standard sound sourcebzxz.net
5.3.2.1 The standard sound source should be placed in the same position as the measured compressor under test, and the replacement can be used as a substitute. In 5.3.2.2, when the small compressor unit is not removed from the measurement site, the standard source should be placed in the same position as the source using the substitution method. Generally, only one position is placed for the units with a large length-width ratio. The standard sound source should be placed in four positions. The standard body should be placed at the midpoint of the short side of the projector on the reflection plane. 5.3.2.3 The power level of the standard source should be measured and measured according to the methods of 5.1 and 5.2. For the case where a standard non-occupied source is placed at a certain position, the standard sound source power level book should be obtained for each receiving point to measure, and the power level of the measuring surface should be calculated. Then the effective average of the three standing points is calculated, and the correction is obtained: K=w-La
The standard power level of the source measured on site is in decibels (the reference value is: 1×1) L
The unit of the standard source calibrated is decibels. The base position is 6. Record content
6.1 The model, name, make and model of the compressor under test: the rated speed and rated power of the driving machine; the rated operating conditions and operating conditions of the compressor (speed, gas flow, etc.) 6.2 Acoustic environment
Record the actual situation and indicate the location of the sound source. Indoor measurements should include the following: the total area of the room, the type of measurement, and the distance between the most sensitive measurement points. Outdoor measurements should include the following: 6.5 Receiver type, name, manufacturer and manufacturer, device characteristics, 6.4 Sound level, reference size, surface area, and measurement point locations, and draw a schematic diagram of the measurement points. A. Weighted sound pressure level of new measuring point: 1. The corresponding sound pressure level certificate; .3. Determine the environmental condition Kd)
Measure the average surface sound level, daily weighted sound level and selected frequency sound level, E.5 Meteorological conditions
Atmospheric pressure, full scale and relative humidity:
6.6 Others
Testing personnel, time, place, other situations that need to be explained: 6.7 Record form
The record form will be attached
7 Measurement report
The sound production rate level measurement report of the unit out of the box shall include the following, in tabular form). a) Size, model, name, manufacturer name, factory number! Driver certificate title:
General test 1 year condition 1 circulation, suction, exhaust positive and negative flow rate; c
Noise measurement data, that is, the calculation rate board and the selected test procedures are determined by the method specified in this standard with the rate level system 5
GB/T 4980—2003
(Normative Appendix)
Simplified method for determination of noise level by sound power setting When the tester is needed or the acoustic environment cannot meet the requirements of 1.1.1 and 4.2.1 of this standard, the determination of the noise level of the machine item during the period of noise emission shall be supplemented by the simplified method specified in this requirement.
A.2 Instruments
A.2.1 Overview
Specially record the sound level meter of type [or - type] specified in G1378515% (Type 2 or above can be used for "test") and modify the receiver with equivalent accuracy. 4.2.2 Calibration
Before and after the measurement, the sound level calibrator with an accuracy of about 10.5 should be used for calibration. If the calibration values before and after the measurement are more than 1.000, the measurement error point should be greater than 1.000. 4.3 Measurement environment, quantity and quantity error point to be determined, 3.1 Liu Xian Environment
4.3.1.1 The wide outdoor field is also the center of the reflection plane, so the center of the reflection plane is the upper bottle surface, and the projection of the measurement surface on it should be 4.3.1.2 The center reflection plane is the plane inside the room, and the floor may not be a brick floor. The method of determining the environment correction position KK is not less than 7
A.3.2 The weighted sound rate to be measured is the maximum error of the measurement according to the appendix:) The weighted power level of the standard is 5% smaller than the center of the standard. When the same type of energy source is measured in the room environment, the difference between the results is not less than 1. A.4 The installation and operation of the compressor unit
is stipulated in this standard.
A.5 Reference volume and attenuation surface
According to the provisions of 4.4 of this standard,
A.6 Double-point sound pressure defect
A.6.1 Back noise
For reference volume, the unit size is less than 3, and the back noise should be measured at a measurement point. The measured pressure level should be in accordance with Table A. : Reverse repair. The measurement point position of the machine will be the standard of 5.-.3.
A.6.3 Measurement
Table A, 1
GB/T2980—2003
Unit: JB
Use the measured unit noise level in the "slow" time weighted standard measurement when the noise level of the unit is measured directly in the line of sight from the noise level of the measuring point to the measured point. At the specified measuring point, measure the A-weighted sound level. After point noise correction, calculate the average sound pressure level and sound power level of the measuring surface in A,7. The calculation formula of A.7.1 is as specified in Section 5,3 of this standard, and the environmental correction value K is as specified in Section 5,3 of this standard. A.7.2 Determination of environmental correction group K The environmental correction value K can be estimated and determined by using standard sound source. The standard sound source is determined according to 5.3.2 of this standard. At this time, the environmental correction value K determined should not be greater than? B. In the absence of standard sound source, the bad point stop index K can be estimated and determined according to the record. The record and measurement report shall be in accordance with the provisions of Chapter 6 of this standard, 4982-2003.iOverview
Appendix B
(Normative annex)
Determination method of noise sound pressure level of compressor unit This annex studies the determination method of noise sound pressure level of compressor unit. According to the provisions of Chapter 4 of the standard or the medical record A, the A-weighted noise level of the impact sewing machine group is determined according to the following formula to calculate the impact sewing machine noise level: L1 = LW-10ig(S./S)
L——A-weighted noise level, unit is (dB> (the standard value is 2_0-Pt); W—A-weighted sound power level, unit is (dB) (the standard value is 1×10); S-the area of the conformal surface calculated according to Figure B.1 and formula (3.2), unit is square meter (b); S.-the reference blood volume is taken as 1.
In the formula:
1=0,,—d:
6.5t 14:
01016-2 No.
... 2.1
The center and are the length, width and distance between the standard surface and the standard work surface respectively. Fixed type compressor -! n, group dynamic small rely on solid =?m.
Green multi-face:
Base bar design.
Figure B, 1 standard body distance between the two standard surfaces. 3 Record and measurement report
This environmental standard draft, Chapter 7, format as shown in Appendix 1) x
Appendix C
(Informative Appendix)
Typical compressor unit standard body C.1Z type compressor unit reference body C.2L type compressor unit reference body GHT49EC-2003 GB/T4960-2003 C.3V type compressor unit reference body Figure 4 Slim rod compressor unit reference body Figure C! 5 Micro compressor unit reference body Figure C.3V type compressor unit reference body Figure C. ...
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