A magnetic flow meter is technically referred to as an electromagnetic flow meter. These are the third most common type of flow meters. The other two meters that are more common than the magnetic type are the positive displacement and differential pressure flow meters.
Commonly, the magnetic meter is known as a mag meter. These types of meters operate according to Faraday's law of electromagnetic induction. According to Faraday's law, as the conductor moves through the magnetic field the voltage is induced. The liquid flowing through the magnetic field serves as the conductor.As for the magnetic field that is created through energized coils that are located on the outside of the flow tube. When it comes to the selection of magnetic flow meters, certain considerations are necessary. This entails things such as the mounting type, pipe diameter, end fittings, performance specifications, special features, and output options. Other important considerations are the ability to monitor media temperature and meter liquids with suspended solids.
In general, these types of meters differ in accordance to their mounting type and pipe diameter. The available options for mounting are the non-invasive, insertion type, and in-line. As for the pipe diameter, this refers to the process pipe, which is going to be monitored.An in-line flow meter is directly installed within the process line. Usually, in order for this type of installation to take place it must be installed on a straight pipe. On the other hand, the insertion-type devices do not have to be installed on a straight line of a pipe.
In most cases, the insertion-type devices require a threaded hole within the process pipe. As for the non-invasive electromagnetic flow meters, they do not have a requirement for direct-mounting within the process flow. Additionally, they can be used within the closed piping systems. Types of magnetic flow meter end fittings include: * Clamp * Compression * Flanged * Plain End * Socket Weld * Union * Threaded * Tube End * Hose Nipple
The external clamp-on flow meters are non-invasive and use compression fittings in order to tighten them over a joint so they do not leak. In most cases, flanges are square or circular and are connected by welding or bolting. As for the plain-end devices, they can be inserted into the end of the connecting pipe.
The interface and electrical output are the two types of options for magnetic flow meters. The available options for electrical output are switch output, frequency, analog voltage and current. The options available for the interface are fieldbus, network, digital, and serial.
In most cases, a National pipe thread (NPT) is used with threaded designs. Generally, hose-nipple fittings or tube-end fittings are used with shorter pieces of pipe that are male threaded. Magnetic flow meters differ in relation to their features. Some of them have the capacity to measure temperature, level, or density and may have features such as visual or audible alarms, in addition to other types of features. Magnetic flow meters are also available for sanitary applications as well.