Factors affecting the measuring accuracy of mass flowmeter

The characteristic of mass flowmeter is that it can directly measure the mass flow rate of medium, and is not affected by the pressure, temperature and other factors of the working state of medium. Factors affecting the measuring accuracy of mass flowmeter:

1. Impact of environmental vibration

Mass flowmeters can operate in vibration environments, but must be isolated from vibration, for example, with a flexible pipe connection and vibration isolation support frame. But the vibration frequency should be prevented from being the same as the working frequency or harmonic frequency of the mass flowmeter. When multiple meters of the same model are installed in series or close parallel, especially when installed on the same support platform, the working frequency vibration of each mass flowmeter will affect each other, causing abnormal vibration, which will make the meter unable to work seriously. When ordering can be specially proposed to the manufacturer, staggered two series mass flowmeter frequency.

2. Influence of fluid density

The change of fluid density changes the mass of the flow measurement system, which changes the balance of the mass flowmeter sensor and causes the zero shift. If a specific liquid is measured, as long as the density condition of the actual liquid is reduced to zero, the density change in the process of use is not big, there is generally no problem. However, when several liquids with different densities are measured in one pipe, the additional error of zero change will be brought about.

3, the influence of fluid viscosity

The mass flowmeter can measure the viscosity of liquid over a wide range, and shows good measurement performance. Although viscosity has been reported to affect measurement accuracy, few test data are available. Liquid viscosity will change the damping characteristics of the system, thus affecting the zero bias. At low flow rate, the measurement value of mass flowmeter is affected to some extent.

The mass flowmeter directly measures the mass flow of the medium through the flowmeter, but also measures the density of the medium and indirectly measures the temperature of the medium. The mass flowmeter does not control the flow rate. It can only detect the mass flow rate of liquid or gas and output the flow value through analog voltage, current or serial communication. Mass flowmeter is a new generation flow meter with flexible configuration, powerful function, high performance and cost. Mass flowmeter is based on Coriolis force, there are two parallel flow tubes inside the sensor, the middle is equipped with a driving coil, and the two ends are equipped with a detection coil. When the excitation voltage provided by the transmitter is added to the driving coil, the vibration tube makes reciprocating periodic vibration. Mass flowmeter is a relatively accurate, fast, reliable, efficient, stable and flexible flow meter, which has been applied in petroleum processing, chemical industry and other fields.