How to reduce the impact of noise on ultrasonic flowmeters
Under the premise of fixed installation conditions, ultrasonic flowmeter improves the signal processing capacity and diagnostic capacity of the flowmeter itself, and can effectively reduce noise. Under normal circumstances, the measuring accuracy of the flowmeter is very important.
In the case that the accuracy cannot be guaranteed, the application of flowmeter to measure the flow rate of a regulator that produces noise will inevitably produce wrong results. Therefore, improving the flow meter’s identification and detection of acoustic pulses, while improving the signal filtering ability, can improve the accuracy of measurement.
In order to reduce noise interference, try to install the flowmeter in the upstream of the regulator, the advantage is that the pressure is higher, the signal is strong, and the noise will not be amplified. Noise is reduced by lengthening the straight pipe section of the flow meter upstream and downstream and installing isolation devices between the flow meter and the noise source. However, the length of the straight pipe section may require multiple pipe diameters to reduce noise interference, so the installation of isolation equipment is more convenient and effective. Ultrasonic noise canceller has remarkable effect on noise reduction. Noise canceller is the use of a single small reflection device with the same wavelength as the flowmeter, foam or viscous, elastic, absorbent some equipment to achieve the purpose of noise elimination. Tests have shown that this method can reduce noise by 30%.
The noise canceller can be directly installed in the downstream of the flow meter, flange connection, will not affect the accuracy of the flow meter. Ultrasonic noise eliminators usually have blockage and a certain pressure drop, so they lose some of their advantages. However, in some cases, such as when compared with the noise generated by the larger pressure drop of the regulator, the pressure drop of the noise suppressor can be negligible. Ultrasonic flowmeters can be used to reduce noise in the case of space constraints such as offshore platforms.
