Common Types Of Flow Meters

There are various types of flow measurement methods and instruments, and there are also many classification methods. Before 2011, there were as many as 60 types of flow instruments available for industrial use. The reason why there are so many varieties is that there is no flow meter that is suitable for any fluid, any range, any flow state, and any usage condition. However, with the progress of the times, in this era of technological explosion, the latest product - mass flowmeter has finally emerged. Mass flowmeter is suitable for any fluid, any range, any flow state, and any usage condition, but it is relatively expensive and cannot be popularized in all industries.
There are over 60 old-fashioned flow meters, each with its specific applicability and limitations. According to the measurement object, there are two categories: closed pipelines and open channels; According to the measurement purpose, it can be divided into total quantity measurement and flow measurement, with instruments called total quantity meters and flow meters, respectively.
In addition, according to measurement principles, it can be divided into the following categories:
1. Mechanics principle: Instruments belonging to this type of principle include differential pressure type and rotor type using Bernoulli's theorem; Using the momentum theorem's impulse formula and movable tube formula; Using the direct mass formula of Newton's second law; Targeting based on the principle of fluid momentum; Turbine type using the angular momentum theorem; Vortex type and vortex street type utilizing the principle of fluid oscillation; Pitot tube type, volumetric type, weir, groove type, etc. utilizing the total static pressure difference.
2. Electrical principles: Instruments used for such principles include electromagnetic, differential capacitive, inductive, strain resistance, etc.
3. Acoustic principle: There are ultrasonic and acoustic (shock wave) methods that use acoustic principles for flow measurement.
4. Thermal principle: There are various methods for measuring flow rate using thermal principles, such as calorimetry, direct calorimetry, indirect calorimetry, etc.
5. Optical principle: Laser type, photoelectric type, etc. are instruments belonging to this type of principle.
6. Atomic physics principles: Nuclear magnetic resonance, nuclear radiation, and other instruments belong to such principles
7. Other principles: including labeling principles (tracing principles, nuclear magnetic resonance principles), related principles, etc.
This article elaborates on the principles, characteristics, application overview, and domestic and international performance of various flow meters based on the currently most popular and widely used classification methods:
Targeted
Target flowmeter is a type of flowmeter based on mechanical principles, which has been developed and applied in industry for decades. The new SBL target flowmeter is a new capacitive force induction flowmeter developed with the development of new sensors and microelectronics technology based on traditional target flowmeters. It has the characteristics of orifice plates, vortex streets, and other flowmeters without movable components, as well as high sensitivity, accuracy comparable to volumetric flowmeters, and a wide range. [3]
In the 1970s, China developed electric and pneumatic target flow transmitters, which are detection instruments for electric and pneumatic unit combination instruments. Due to the fact that the force converter at that time directly used the force balance mechanism of the differential pressure transmitter, this flow meter inevitably brought many defects caused by the force balance mechanism itself, such as easy zero drift, low measurement accuracy, and poor reliability of the lever mechanism. Due to the poor performance of the force balance mechanism, many advantages of the target flowmeter itself have not been effectively utilized, and the negative impression of the old target flowmeter by users has not been eliminated to this day.
The force converter of the new SBL target flow meter adopts a strain type force converter, which completely eliminates the shortcomings of the force balance mechanism mentioned above. The new target flow meter also applies microelectronics technology and computer technology to the signal converter and display part. The flow meter has a series of advantages and is believed to play an important role in many flow meters in the future.