Instruments that measure fluid flow are collectively referred to as flow meters or flow meters. The flowmeter is one of the important instruments in industrial measurement. With the development of industrial production, the accuracy and range of flow measurement requirements are getting higher and higher, and the flow measurement technology is changing with each passing day. Various types of flow meters have been introduced to suit various applications. More than 100 flow meters have been put into use. From different perspectives, flow meters have different classification methods. There are two commonly used classification methods. One is to classify according to the measurement principle adopted by the flowmeter: the second is to classify according to the structural principle of the flowmeter.
Sort by measurement principle
a. Mechanical principle:
Instruments belonging to such principles have differential pressure type, rotor type using Bernoulli's theorem;
Impulse type using the momentum theorem, movable tube type;
Direct mass equation using Newton's second law;
a target using the principle of fluid momentum;
Turbine using the angular momentum theorem;
Vortex type using vortex principle of fluid oscillation;
Use the total static pressure difference of the pitot tube type as well as volumetric and sputum, trough and so on.
b. Electrical principle:
Electromagnetic,
Differential capacitor type,
Inductive,
Strain resistance type, etc.
c. Acoustic principle:
Ultrasonic.
d. Thermal principles:
Thermal type,
Direct calorimetry,
Indirect calorimetry and so on.
Advantages of turbine flow meters
The pressure loss is small, and the impeller has anti-corrosion function;
1.Adopt advanced ultra-low power single-chip microcomputer technology, the whole machine has strong functions, low power consumption and superior performance.
2.Intelligent flow display with nonlinear accuracy compensation. Correction formula accuracy is better than ±0.02%
3.The meter factor can be set online by button and can be displayed on the LCD screen. The LCD screen is intuitive and clear, and the reliability is strong.
4.EEPROM is used to accumulate the flow and the meter coefficient is powered down. The protection time is more than 10 years.
5.Using high-performance MCU central processing unit to complete data acquisition and processing display output, cumulative flow instantaneous flow
6.The screen displays a convenient man-machine interface for data transfer in standard 485 format.
7.Fully hard alloy (tungsten carbide) shielded cantilever beam structure bearing, integrating rotary bearing and pressure bearing, greatly improving bearing life and working in medium with a small amount of sediment and dirt.
8.It adopts 1Cr18Ni9Ti all stainless steel structure (the turbine adopts 2Cr13) and has good anti-corrosion performance.
9.Easy to maintain, self-rectifying structure, small and light, simple structure, which can be combined in a short time.
10.Internal cleaning is simple.
11.Strong anti-magnetic interference and vibration capability, reliable performance and long life
12.The lower limit flow rate is low and the measuring range is wide.
13.The on-site display type LCD screen is clear and intuitive, with low power consumption. The 3V lithium battery can be operated continuously for more than 5 years.
Corrosion resistant, suitable for acid and alkali solutions
Second, gas turbine flowmeter measurement characteristics
1. Gas turbine flowmeter is one of the main types of flowmeters. Its working principle is: the gas entering the gas turbine flowmeter is accelerated by the fluid, and the accelerated gas acts on the blades of the turbine through the inlet passage. The impulse causes the turbine of the flow meter to rotate in the flow path, and within a certain flow range, the number of revolutions of the turbine is proportional to the volume of the gas flowing therethrough. By mechanical or electromagnetic induction, the number of revolutions f of the turbine can be obtained, so that the flow rate Q of the gas flowing through the flow meter can be obtained.
2. Gas turbine flowmeters are widely used in the measurement of gas flow or total gas volume, and are widely used in natural gas flow measurement at home and abroad. The theoretical research and practical experience of gas turbine flowmeters are very mature, and there are corresponding international standards. Countries also have corresponding national standards. China also adopts international standards. In Europe and the United States, gas turbine flow meters are the most important gas flow meters, and the Netherlands alone uses more than 2,600 gas turbine meters on natural gas pipelines.