Selection Characteristics of Various Flow Meters

April 18,2022

In recent 30 years, with the rapid development of the international economy, science, and technology, flowmeter has attracted more and more attention. To meet the characteristics of different types of fluids and solve the problem of flow measurement under different flow conditions, dozens of flowmeters have been developed and put into use in various countries, and there are hundreds of flowmeter products on the market at home and abroad.


flow meters


Mass flowmeter


  • Applicable materials


Applicable to a variety of media


  • Principle structure


The mass flowmeter is based on Coriolis force. There are two parallel flow tubes inside the sensor, with a driving coil in the middle and a detection coil at both ends. When the excitation voltage provided by the transmitter is added to the driving coil, the vibrating tube vibrates back and forth periodically. When the fluid medium of the industrial process flows through the vibrating tube of the sensor, the Coriolis force effect will be generated on the vibrating tube, causing the two vibrating tubes to torsional vibration, The detection coils installed at both ends of the vibrating tube will produce two groups of signals with different phases, and the phase difference of the two signals is proportional to the mass flow of fluid flowing through the sensor. The mass flow through the vibrating tube is calculated by a computer. When different media flow through the sensor, the main vibration frequency of the vibrating tube is different, and the media density is calculated accordingly. The platinum resistance installed on the vibrating tube of the sensor can indirectly measure the temperature of the medium.


  • Measurement characteristics


The mass flowmeter directly measures the mass flow of the medium passing through the flowmeter, and can also measure the density of the medium and indirectly measure the temperature of the medium.


  • Matters needing attention


  1. When measuring gas, some models are only applicable to the measurement of air and other gases close to the ideal, while some can use natural gas and steam. Consult the manufacturer in detail.


  1. If the measuring medium has air entrainment, gasification, or two-phase flow, the transmitter will give an alarm display. In serious cases, the sensor will stop working.


Orifice flowmeter


  • Applicable materials


It is widely used in the flow measurement of gas, steam, and liquid.


  1. It is more suitable for measuring saturated steam, superheated steam, gas, cooling water, and other dirty fluids.


  1. It is easier to adapt to the flow measurement of high temperature and high-pressure fluid.


  • Principle structure


LG orifice flowmeter, also known as differential pressure flowmeter, is composed of primary detection parts (throttling parts) and secondary devices (differential pressure transmitter and flow display instrument). Pressure equalizing ring and integrated structure are adopted.


  • Measurement characteristics


The throttling device has the advantages of easy replication, simple and firm structure, stable and reliable performance, long service life, and low price.


The integrated orifice plate is easier to install and can be directly connected to a differential pressure transmitter and pressure transmitter without a pressure pipe.


The intelligent type works continuously for 5 years without an adjustment.


  • Matters needing attention


When installing the orifice flowmeter, it shall be equipped with a section of measuring pipe, and at least the equal diameter straight pipe section of the first 10dn and the last 5dn shall be maintained to improve the measurement accuracy.


Searching for a flow meters supplier from China, you can get high-quality products at a nice price.