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Flow Meter

Flow Meter Types ?

The flowmeter is a kind of meter used to measure the flow of fluid in a closed pipe or open channel. How to choose the right flow meter for different applications and media and working conditions? To help you solve the problem of how to select the flow meter, Silver Automation Instruments has collect some information for your reference.

How to select a flowmeter which can work for your application also with cheap price? According to the measurement principle, there are differential pressure flow meters, rotor flow meters, positive displacement flow meters, turbine flow meters, electromagnetic flow meters, vortex flow meters, ultrasonic flow meters, thermal gas flow meters, etc.Different types of flowmeter selection methods and reference factors are also different, and should be selected according to their specific functions and performance. Below I will introduce the commonly used flowmeters:

Magnetic Flowmeter

mag flow meter

Electromagnetic flowmeter is an instrument for measuring conductive liquid made according to Faraday's law of electromagnetic induction. When the conductive fluid moves in the direction of the magnetic field line in a magnetic field, it will induce an induced electromotive force whose direction is perpendicular to the direction of the magnetic field and the direction of the fluid flow, and its value is proportional to the magnetic induction intensity and the fluid movement speed. The electromagnetic flowmeter is composed of two parts, the sensor and the converter, and it can also be made into an integral type or remote transmitter. Magnetic flowmeter has many excellent features, can measure dirty flow and corrosive flow;

Mag flowmeter can measure sea water, sewage, sulfuric acid, nitric acid, sodium hydroxide, corrosive liquid, hydrofluoric acid, potassium nitrate, mud, milk, pulp, water, fire fighting water;It can measure various corrosive liquids such as acid, alkali and salt, and can be used as an acid flowmeter and an alkali flowmeter.
Mag flow meter sensors normally used: 1/2 inch Magmeter, 1”, 2”, 3 inch, 4 inch, 6 inch mag flow meters, 8 and 10 inches magnetic flow meters.

Magnetic flowmeter has an electronic display that can display the instantaneous flow and cumulative amount of the liquid, and also it is bi-directional flowmeter;
It can be made into an industrial inline type flow meter or insertion type magnetic flow meter;
Mag mete cannot be used to measure gases, vapors, and liquids containing large amounts of gas.
Magnetic flowmeter cannot be used to measure liquid medium with very low conductivity and cannot measure high temperature and high pressure fluids.

Positive displacement flow meter

Positive displacement flow meter

Positive displacement flow meters are also called PD flow meters. The fluid is continuously divided into single known volume parts by mechanical measuring elements, and the total fluid volume is measured according to the number of times that the measuring chamber is filled and discharged with this volume part of fluid successively. Positive displacement flow meters are classified according to their measuring components, which can be divided into oval gear flow meters, roots flow meters, helical gear flow meters,Bi rotor flowmeter, membrane gas meters (domestic fuel meters), etc. Positive displacement flow meter can be used to measure diesel, gasoline, heavy oil, biodiesel, asphalt, methanol, kerosene, lubricating oil, grease .,etc. The material can be 1/2”,1”,2”, 3”,4”,6”,8” and 10 inch PD flow meters.

Now we have developed micro PD flow meters for low flow liquid measurement, the flow meter size can 2mm, 4mm, can detect low flow starts from 0.6 L/h. It can be made into Teflon material for corrosive and aggressive liquid flow rate measurement.

Coriolis mass flowmeter

coriolis meter

Coriolis mass flowmeter is a direct mass flowmeter that uses the principle of Coriolis force proportional to the mass flow rate when the fluid is in a rotating system while moving in a straight line.

Coriolis flowmeter is widely used in petrochemical and other fields. It is one of the most advanced flow measuring instruments in the world. .It can be used to measure liquid, gas, steam, etc. It can measure medium with extremely high viscosity, for example, as a resin flowmeter. , syrup flow meter, asphalt, heavy oil ,glue,etc.

The min size for Coriolis flow meter we can produce is 3mm which can detect mass flow 0-40 kg/h, normal request Coriolis flow meter : 1 inch Coriolis flow meter, 2inch, 3 inch, 4 inch, 6 inch , 8 inch, 10 inch and 12inch Coirolis flow meter.

Vortex flowmeter
vortex flow meter

Vortex flowmeter is to place a non-streamline vortex generator (bluff fluid) in the fluid, and the fluid alternately separates and releases two series of regularly staggered vortices on both sides of the generator. Within a certain Reynolds number range, the separation frequency of the vortex is proportional to the average flow velocity in the pipeline, and various types of detectors can be used to detect the vortex frequency.

Vortex shedding flow meter is mainly used for flow measurement of industrial pipe medium fluid, such as gas, liquid, steam and other medium. It is characterized by small pressure loss, large measuring range and high precision. It is almost unaffected by parameters such as fluid density, pressure, temperature and viscosity when measuring the volume flow rate. We often use vortex flow meter to measure steam (with external pressure and temperature compensation), ,measure low-conductive liquids and clean gas.

Turbine flowmeter

turbine flow meter
Turbine flow meter is a kind of velocity flow meters. They use a multi-blade rotor (turbine) to sense the average flow rate of the fluid to deduce the flow rate or total volume. The rotational movement of the rotor can be detected by mechanical, magnetic induction, optical or electronic means and displayed or recorded by a reading device. Generally, it is composed of two parts, a sensor and a display, and it can also be made into an integral type. Turbine flowmeters can be made into 0.5% accuracy.

Flow meter size can be 6mm,10mm,1/2”,3/4”,1”,1.5”,2”,3”,4”,5”,6”,8”,10”.
Turbine flow meters are widely used in the following measurement objects: petroleum, diesel, portable water, deionized water, drinking water, acetic acid, organic liquids, inorganic liquids, liquefied gases, natural gas, gas and cryogenic fluids.
Digital turbine flow meters can be powered by 24V DC or 220V AC, it can have 4-20mA, pulse or frequency outputs; It can also have MODBUS, RS485 or HART protocol.

Thermal (gas) mass flowmeter
thermal flow meter
Thermal mass flowmeter is a digital gas flow meter that uses the relationship between fluid flow and heat source to transfer heat to the fluid to measure gas flow. At present, there are two types commonly used: one type is a thermally distributed (also known as calorimetric) flowmeter, which is mainly used for small and micro gas flow measurement or used as lab gas flow meter. If it is used as a component flow type, it can also be used in large and medium flow; the other type It is a thermal dispersion type (also known as King's law) flowmeter, made as an insert type gas flow meters, used for large size flow measurement or circular piping or rectangular ducts. Thermal flow meters directly detect mass flow meters, which are mainly used for gas flow measurement, flue gases, LPG , Flare gas ,Propane ,Compressed air,Biogas, N2,O2.,etc;


metal tube rotarmeter
Rotameter is a kind of variable area flowmeter. In a vertical tapered tube that expands from bottom to top, the gravity of the float with a circular cross-section is borne by the hydrodynamic force, so that the float can rise and fall freely in the tapered tube. The position of the float indicates the amount of flow. Rotameters are divided into two categories according to the material of the cone tube: glass tube and metal tube rotameters. According to the remote transmission type, it is divided into: electric remote transmission with 4-20mA output and local reading type without any power supply. Float flow meters are especially for small and micro flow measurement.

It can be used to measure the flow of liquids, gases, and vapors, rotameters sizes are 1/2”,1”,2”,3 inch rotameters, 4 inch, 6 inch and 8” rotameters.

Ultrasonic flowmeter

ultrasonic flow meter

The ultrasonic flowmeter is a flow meter that measures the flow rate by detecting the effect of fluid flow on the ultrasonic beam (or ultrasonic pulse). According to the principle of signal detection, ultrasonic flowmeters can be divided into transit time ultrasonic flow meter, Doppler ultrasonic flow meter, beam shift method, = noise method, etc. There are no obstructions in the flow channel of the instrument, it can also be non-invasive flow meter. They are a type of flowmeter suitable for solving difficult problems in flow measurement, especially in large-diameter flow measurement. It is one of the flowmeters that have developed rapidly in recent years. Transit time ultrasonic flow meter can be used to measure clean water or diesel.

Differential pressure flow meter

Differential pressure flow meter
Differential pressure flowmeter is a flow metering instrument that calculates the flow rate based on the differential pressure generated by the flow detection primary flow element, the known fluid conditions, and the geometric dimensions of the primary element and the pipeline.
Differential pressure flowmeter is composed of a primary element (detection part) and a secondary device (differential pressure transmitter and flow display instrument). Differential pressure flowmeters are usually classified by the type of detection parts, such as orifice flowmeters, venturi flowmeters, and V-cone flowmeters.,etc. The detection parts of the differential pressure flowmeter can be divided into several categories according to its principle of action: throttling type, hydraulic resistance type, centrifugal type, dynamic pressure head type, dynamic pressure gain type and jet flow type. Generally, the throttling type differential pressure flowmeter is the mostly used.
The selection of flowmeters is impossible to be quite perfect, because each flowmeter has its own unique advantages and disadvantages. It can only be selected according to different measurement methods and structures, requiring different measurement operations, methods of use and conditions of use to select safe and economical safety, the best type of durability.

Information Needed To Select a Flow Meter

1. The name and characteristics of the fluid (corrosive, viscous, abrasive, etc.)
2. Working flow (normal flow, maximum flow, minimum flow)
3,Working pressure (maximum, minimum working pressure), if there is negative pressure formation, please specify to China Flowmeter factory.
4, working temperature
5, the conductivity of the fluid, electromagnetic flowmeter can only measure the medium with conductivity ≥ 5μS / cm.
6, Collect the installation location and installation method, such as flange connection, or wafer connection, or threaded connection, or sanitary tri-clover connection flow instruments.
7. Power supply mode, such as battery power supply, or 220V AC power supply, or 24V DC public power supply.
8, process pipe size
9, Please provide communication methods, such as the need to output 4-20mA, or pulse output, or RS485 and so on.
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