Future development of flow meters (2)
The following explains the principles and characteristics of various flow meters one by one.
压差式流量计 Differential pressure flowmeter
Differential pressure flowmeter is a meter that calculates the flow based on the pressure difference generated by the flow detection element installed in the pipeline, the known fluid conditions, and the geometry of the detection element and the pipeline. The differential pressure flowmeter is composed of a detection element (primary device) and a differential pressure conversion and flow display instrument (secondary device).
The advantages of the differential pressure flowmeter are: solid mechanism, stable and reliable performance, long service life; a wide range of applications, so far no other type of flowmeter can be compared with it; detection parts, transmitters, display instruments are different from Produced by manufacturers to facilitate scale generation.
The disadvantages of the differential pressure flowmeter are: the measurement accuracy is generally low; the range is narrow; the site installation conditions are high.
Differential flowmeter is the most widely used type of flowmeter, and its usage ranks first among various flow meters. In recent years, due to the advent of various new types of flowmeters, the percentage of usage has been gradually decreasing, but it is still the most important type of flowmeters. 1/4-1/3 。 Its use in various industrial sectors accounts for about 1 / 4-1 / 3 of the total use of the flow meter .
浮子流量计 2.Float flowmeter
Float flowmeter, also called rotor flowmeter, is a type of variable area flowmeter. In a vertical cone tube that is enlarged from bottom to top, the weight of the float with a circular cross section is borne by the liquid power, so that the float It can rise or fall freely in the cone. Especially in small and micro flow, it plays a pivotal role.
The advantages of the float flowmeter are: the glass cone tube float flowmeter has a simple structure and is easy to use;
The disadvantages of the float flow meter are: low pressure resistance, fragile glass tube, etc.
Float flowmeter is suitable for small diameter and low flow velocity fluid measurement.
容积式流量计 3. Volumetric flowmeter
Positive displacement flowmeter is also called fixed displacement flowmeter with high measurement accuracy. It uses mechanical measuring elements to continuously divide the fluid connection into known volume parts, and measures the total volume of fluid according to the number of times the measurement chamber is filled and discharged repeatedly.
Volumetric flowmeters can be divided into elliptical gear flowmeters, scraper flowmeters, double-rotor flowmeters, rotary piston flowmeters, reciprocating piston flowmeters, original flowmeters, liquid-sealed drum-type flowmeters, and wet-type flowmeters according to their measuring elements. Gas meters and membrane gas meters.
The advantages of volumetric flowmeters are: high measurement accuracy; installation pipeline conditions have no effect on measurement accuracy; can be used for measurement of high viscosity liquids; wide range; direct-reading meters can directly obtain the cumulative total without external energy, clear and clear , Easy to operate.
Disadvantages of positive displacement flowmeters are: complex structure and large volume; the type, diameter, and working condition of the medium being tested are limited; they are not suitable for high and low temperature situations; most meters are only suitable for clean single-phase fluids; vibration and noise Larger.
(Future development of flowmeter (2) To be continued)