The volume of fluid is a function of fluid temperature and pressure and is a variable. The mass of fluid is a quantity that does not change with changes in time, space temperature and pressure. The flow measurement of conventional flow meters (such as orifice plate, turbine, Vortex, electromagnetic, rotor meter, ultrasonic and oval gear meter) is the volumetric flow rate of the fluid. The fluid volumes involved in activities such as scientific research, production process control, quality management, economic accounting, and transfer of trade are generally of high quality. Using the above flow meter to only measure the volumetric flow rate of the fluid often cannot meet people's requirements. Generally, efforts must be made to obtain the mass flow rate of the fluid.

With the development of modern science and technology, measurement methods and devices for directly measuring mass flow have emerged one after another, promoting the development of flow measurement technology.

1. Working principle

A mass flow meter is a heat-sensitive measurement that measures flow by dividing the molecules by taking away the molecular mass. Because it is a thermal measurement, changes in gas temperature and pressure will not affect the measurement results. Mass flow meter is a relatively accurate, fast, reliable, efficient, stable and flexible flow meter. It will be more widely used in petroleum processing, chemical industry and other fields. It is believed that it will show great potential in promoting flow measurement.

2. Introduction to the advantages and disadvantages of mass flow meters

Mass flow meters directly measure mass flow and have high measurement accuracy. It can measure various fluid ranges, including various liquids with high viscosity, slurries containing solids, liquids containing trace amounts of gas, and medium and high-pressure gases with sufficient density. The vibration amplitude of the pipeline is small and can be regarded as inactive parts. There are no obstacles and activities in the measurable pipeline.

(1) Disadvantages:

The zero point of the mass flow meter is unstable, resulting in zero point movement, which affects the improvement of accuracy. Therefore, in many model circles, the total error can only be divided into two parts: basic error and zero point unstable measurement.

(2)Advantages:

Multi-parameter measurement can measure heavy flow and simultaneously obtain the maximum value, density value and frustration value of volumetric flow.

It is insensitive to the distribution of influencing quantities, such as pressure, temperature, density, etc., as well as flow velocity.

Easy to install, sensor pipes of various sizes can be freely moved toward the entrance and exit.

Achieve real high-precision flow measurement by directly measuring the quality of fluid.

There are no characters pumping out of the pipes. Since there are no moving parts and no electrode contamination, the failure rate is low because the house is small, so it is easy to clean, maintain and manage.

It can measure gases, chemicals, papermaking black liquor, pulp and other media from the side.

By accurately measuring high, low, and low-flow gases, issues such as internal food intake, anti-fouling, explosion-proof, and lung tolerance have all been satisfactorily resolved.

It is very convenient to adjust and use, and there is no need for straight pipe sections at the inlet and outlet.

By accurately measuring high, low, and low-flow gases, issues such as internal food intake, anti-fouling, explosion-proof, and lung tolerance have all been satisfactorily resolved.