Pump noise, pump noise standard
The sound power level measurement method in this standard is equivalent to the international standard ISO 3746-1979 "acoustic-noise source sound power level measurement - general measurement method".
1. Main content and scope of application
This standard specifies the method of noise measurement and evaluation of pumps. This standard is applicable to all types of pumps and pump speed regulating fluid couplings other than submersible pumps and reciprocating pumps. The sound power level method should be preferred when applying this standard, and the sound pressure level method should be used when the conditions are not available. In case of dispute, the sound power level shall prevail.
2. Reference standard GB 3102.7
Acoustic quantity and unit GB 3240 Common frequency in acoustic measurement GB 3241 Acoustic and vibration analysis 1/1 and 1/3 octave filter GB 3768 Noise source sound power level determination simple method GB 3785 Sound level meter electrical and acoustic level and test method GB 3974 Acoustic terminology JJG 176 Sound pressure level calibrator trial verification procedure JJG 188 Sound level meter test verification procedure JJG 277 Standard sound source verification procedure
3. Sound power level measurement method of pump
The sound power level measurement method specified in this standard is consistent with the method specified in GB 3768. This method can accurately understand the noise level of the pump or pump unit. When it is necessary to accurately measure the sound power level of the pump sound source, the influence of the noise of the prime mover (motor, internal combustion engine, etc.) should be considered, and if necessary, the sound source (such as sound insulation cover) should be used to reduce the influence.
3.1 Measurement error
Measurement error refers to the cumulative standard deviation caused by various factors. The error of the sound power level of the measuring pump according to the provisions of this standard is: a. For the pump sound source, the standard deviation is not more than 4dB; b. When comparing the same type of pump in the same test environment, the standard deviation is not more than 3dB.
3.2 Acoustic measurement environment
The ideal acoustic measurement environment should be no reflective object other than a reflective surface (ground). It is approximately a free field above the reflecting surface. The measurement environment suitable for this standard is a wide outdoor or room that meets the requirements. The noise of the measuring pump is generally carried out in the laboratory (test pumping station).
3.2.1 Requirements for the measurement environment (laboratory, test pumping station)
The standard for assessing whether the laboratory meets the requirements is A/S ≥ 1 (A is the sound absorption of the laboratory room, S is the area of the measurement surface) or the environment. The correction value K2 ≤ 7.
3.2.2 Requirements of background noise
At the measuring point, the difference between the A sound level measured by the pump and the A sound level of the background noise and the A sound level of the background noise should be at least greater than 3 dB.
3.2.3 Wind speed
When measuring outdoor, the wind speed should be less than 6m/s and the windshield should be used. When measuring outdoor, the windshield should be used when the motor is cooled and ventilated too much (feel).
3.3 Test equipment
3.3.1 General The test equipment shall use the sound level meter of type 2 or above specified in GB 3785, and other test instruments of comparable accuracy. It is best to use an extension cable or extension rod between the sound level meter or other test instrument and the microphone.
3.3.2 Calibration
Before and after each measurement, the entire test system (including the cable) shall be calibrated at one or more frequencies with a sound level calibrator with an accuracy better than ±0.5 dB. Sound level calibrators shall be in accordance with JJG 176 procedures, sound level meters and other test instruments shall be periodically verified according to JJG 188 procedures to ensure the accuracy of the test instruments.
