Flowmeters are devices for measuring the flow rate or quantity of a moving liquid or gas. There are four basic categories of devices: differential pressure (DP), positive displacement (PD), velocity, and true mass.
Types of Flowmeters
Differential pressure flowmeters obtain the flow rate by measuring the pressure differential and extracting the square root. Choices for DP meters include cone-type devices, elbow tap meters, flow nozzles, laminar flow elements, orifice plates, Pitot tubes, rotameters, target meters, variable area flow meters, and Venturi tubes.
Positive displacement flowmeters divide the media into specific increments which can be counted by mechanical or electronic techniques. Examples of PD meters include nutating disc devices, oval gear meters, and piston-based designs.
Velocity flowmeters operate linearly with respect to the flow rate. Because there is no square-root relationship, their range is greater than DP devices. Choices for velocity meters include electromagnetic meters, paddlewheels, sonar-based devices, turbine meters, ultrasonic meters and vortex or shedding meters.
True mass flowmeters are used to directly measure the mass rate of flow. These flow meters include both thermal meters and Coriolis meters.
When selecting electromagnetic flow meters, parameters include pipe diameter, mounting type, end fittings, performance specifications, output options, and special features. The ability to meter liquids with suspended solids (slurries) and monitor media temperature are also important considerations.
Electromagnetic flow meters differ in terms of pipe diameter and mounting type. Pipe diameter is the diameter of the process pipe to be monitored. Choices for mounting type include in-line, insertion type, and non-invasive. In-line flow meters are installed directly in the process line and typically require a straight run of pipe. By contrast, insertion-type devices are inserted perpendicular to the flow path. Usually, they require a threaded hole in the process pipe. Non-invasive electromagnetic flow meters do not require direct-mounting in the process flow and can be used in closed piping systems.
There are two types of output options for electromagnetic flow meters: electrical output and interface. Choices for electrical output include analogue current, analogue voltage, frequency and switch output. Interface options include serial or digital, and network or fieldbus.
Electromagnetic flow meters differ in terms of features. Some devices can measure density, level, or temperature. Others feature audible or visual alarms, averaging or multi-insertion functions, controller functions, programmability, and recorder or totalise functions. Electromagnetic flow meters that are designed for use in sanitary environments, such as in medical or food processing applications, are also available.
Universal Supplies (Clydesdale) Ltd……..01555 772474
At universal supplies (clydesdale) ltd we are able to supply all types of flowmeter, flow sensors for all applications. Please get in touch with our office with any enquiries that you may have.