Traffic problem solving
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Our company plans to replace the mass flow meter with an ultrasonic flow switch. The experimental procedure involves installing the ultrasonic flow switch in the pipeline where the mass flow meter is located (it remains to be determined whether vertical or horizontal installation makes a difference). For easier comparison, an integrator is installed near the mass flow meter transmitter. The mass flow meter transmitter displays the value in Kg/h, while the ultrasonic flow switch shows it in L/min; when converted to Kg/h for use in the accumulator, the result is (ultrasonic display value * 60 * density of the liquid being measured). It was found that there is a significant discrepancy between the value shown by the mass flow meter transmitter and that displayed by the accumulator. For example: if the ultrasonic flow switch shows 2.9 L/min, this corresponds to 300.5 Kg/h when converted to the accumulator ； And the mass flowmeter transmitter shows 200 Kg per unit. Could you let me know why?:)
Is the material density stable? Additionally, pipeline vibration has a significant impact on ultrasonic flowmeters.
Is this data usage normal? Is 0.2T/H really too low? Has the flow rate been increased and was the difference measured? Or are the mass flow meter parameters correct?
A flow rate of 200 kg/h is quite low; for a standard 15-inch pipe, the flow velocity is less than 0.4 m/s, often around 0.3 m/s. A mass flow meter is suitable for this situation, but due to the low flow rate, measurement errors can occur. If the ultrasonic mass flow meter provides stable measurements, and it is used as a switch for control purposes, by adjusting the alarm flow rate up or down, control can be achieved; there is no need to worry too much about the accuracy of the measured flow rate. For accurate measurement, a mass flow meter is the preferred choice.
Firstly, ultrasonic flowmeters and mass flowmeters are not in the same category at all. Secondly, it is difficult to say whether an ultrasonic flowmeter is functioning to provide accurate flow measurements, while mass flowmeters offer a much higher degree of reliability.
Ultrasonic waves, crazy woman – if you think of it as a measuring toy, then you’re right,,, but definitely don’t treat it as a measuring instrument.
The ultrasonic wave measures the flow velocity, which is then converted into volumetric flow rate; the mass flow meter directly measures the mass flow rate
Factors such as the distance between the two flowmeters, whether the medium undergoes a phase change as it passes through the flowmeters (that is, changing from a single liquid to a two-phase flow of liquid and vapor), the presence of valves before, after, and between the flowmeters, and whether the pipeline vibration is excessive (above the acceptable range for ultrasonic measurement), all contribute to significant errors in the readings of the two flowmeters (especially in the case of ultrasonic flowmeters). There are many types of flow switches, and there is no need to be limited to ultrasonic flow switches.
Check the mass flowmeter gauge to see if there is any change in the medium density