Gas and liquid Flow measurement in pipes has a long history and and it started some 300 years ago when an Italian physicist Daniel Bernoulli postulated his famous hydraulics principle and theorem in which the change in differential pressure is in inverse proportion to the flow rate in the pipe. Thus if there is an obstruction in the pipe, the flow rate can be measured by measuring the differential pressure. Continue reading
When selecting liquid flow meters it is all too easy to go with the flow, as it were, and specify what you always have done for a given application. You may be missing some great options from the myriad of types available.
First of all, do you want volumetric flow or mass flow measurement? The difference could be quite fundamental to your process or other applications. Continue reading
Ultrasonic flow meters based on the Doppler Effect, have been around for decades and they provide a great way to measure full pipeline flow without affecting the fluid passing the measurement point. Like all flow meter measurement methods, they have their limitation of possible applications. Doppler Ultrasonic flow meters suffer from not being effective at low flows where the pipeline velocity is very low. They also have problems with clean water or pure liquid flows in that they measure the speed of particles in the flow. At the other end of the scale, they also have problems with high particulate sludge or slurry flows in that the ultrasonic pulse cannot penetrate the flow medium. Continue reading
The waste water and sewerage industry looks after the waste water water from a wide range of populations and industries by measuring it with liquid flowmeters to see how much is being produced for planning purposes and environmental impact assessments, and treating it to reduce its impact on the environment. With our crowded planet, this industry keeps civilisation going by stopping all of us drowning in excrement and toxins. Continue reading
The Construction Industry is often seen (with some justification on past practices) by the general public in the manner of locusts descending on sites, laying waste and polluting the adjacent water courses and then moving on after permanently affecting the landscape. However, things are changing along with the plant and equipment contractors use to comply with the ever increasing regulation. Liquid flow meters are part of the modern contractors’ armoury. Continue reading
The number of different types of liquid flowmeters used in industry, is quite diverse and therefore it is advisable to understand the basic principles of most of them so that you, as a designer or performance specifier, can make an informed choice about which type will suit the application best. Factors should include not only the accuracy of measurement over the flow range, but also its whole life costing for maintenance and parts renewal. Today, we have a look at Coriolis Mass flowmeters. Continue reading
Electromagnetic flowmeters can be used with slurries and liquids as long as the liquid can conduct electricity. Mounted directly inside the pipe is the flow tube. The drop of pressure across the flowmeter is exactly the same to the one in the pipe of equal length, since there aren’t any obstructions or moving parts to disrupt flow. Continue reading
Mechanical flowmeters are the most commonly used meters for so-called pressurized systems. Propeller, positive displacement and vortex are three types of mechanical flowmeters. Continue reading
Because a pipe’s cross sectional area is known and remains the same before and after a flowmeter’s insertion, average velocity indicates flow rate. The viscosity and density of the liquid will affect flow rate, as will the friction of the liquid that touches the pipe walls. Continue reading
Agriculture is one industry where water flow rate must be measured, and there are many types of flowmeters that can be used for measuring the flow rate of water.
An electromagnetic full pipe meter can be fitted on pipes up to 8 inches in diameter, and are accurate to 0.5%. Usually, five inches of straight pipe are sufficient before the meter intake, with two inches or less required downstream, though these numbers will vary. The smaller flowmeters of this type are less expensive. Continue reading
