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Technology Technology How Do Flow Meters Work - Flowmeter Types And Operation
Technology Technology How Do Flow Meters Work - Flowmeter Types And Operation
| How Do Flow Meters Work - Flowmeter Types And Operation |
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| Written by Adrian Fletcher |
| Friday, 25 July 2008 08:24 |
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The need to measure the flow rate in a pipe or tube has many aaplications for individuals and in business. Generally, gases and liquids need to be measured. there are two ways to do this. The volumetric flow rate is a measure of the volume of the medium by time. The mass flow rate is a measure of the mass of the medium by time. There is a diverse range of uses for flow meters. They have applications for individuals, a common one being to help people with asthma. A peak flow meter measures the lung capacity when someone exhales. This can help to predict an imminent asthma attack. Other than that, flow meters are used in many industries, like the food processing industry, water management, semi conductor fabrication and many others. This article will give a brief overview of how flow meters work. Flow meters are generally classified by the type of flow rate that they measure or by the fundamental principle that governs their operation. Mass flow meters measure the mass flow rate but there are many types of mass flow meters, each having a different method to arrive at this measurement. The Coriolis flow meter is a point in case of a principle giving it's name to the type of flow meter. The Coriolis effect is the force exerted on a liquid moving in a circular motion. In the flow meter this is done by vibrating the pipes that the liquid passes through. The vibrations (or waves) that are created in the pipes are changed when the liquid passes through them. By knowing the changes in the wave vibrations you can work out the flow rate of the liquid. The ultrasonic flow meter and Doppler shift flow meter also use wave mechanics to determine the flow rate of the medium passing through a pipe or tube. In the case of the ultrasonic flow meter, two transmitters of ultrasonic sound waves are placed at the ends of a pipe where the measure is to take place. Each transmitter sends a pulse of sound. The ultrasonic waves are recorded by receivers at opposite ends of the pipe. One wave is sent in the direction of the flow of the liquid to be measured. The other wave is sent in the opposite direction to the flow. The flow rate can be determined by the difference in the timings of each ultrasonic wave provided information on the material of the pipe and some details on the medium being measured are known. Doppler shift meters use a sound wave that bounces off matter in the medium passing through the pipe. Due to the Doppler effect, the frequency of the waves changes when it strikes a moving object. This change in the frequency can be used to determine the flow rate of the medium passing through the pipe. A more traditional type of flow meter is the variable area flow meter that uses a float in a calibrated tube. When a substance passes through the tube, the float is displaced by the flow. By taking the reading from the calibrated tube an indication of the flow rate can be determined. This is the principle of the peak flow meter used for lung capacity and asthma. About the Author: Learn more about flow meters, specifically on portable flow meters at http://www.flowmetermatters.com. Kindly provided by LJ-Marketing.dk You are welcome to use this article on your own website, if you include the link just before this text. |
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