It's a crucial step to measure flow rates, particularly when working in large industrial plants as it can tell the loss or the profit of a business. To measure flow rate, either by mass or volume, a device called a flow meter is used. It works by measuring the amount of liquid that passes through pipes.
What is a Flow Meter's Function?
Flow meters are used in several kinds of applications to measure mass or volume flow rates. The specific use of the meter determines the capacity and style of it. Liquid and gas fluids are both measured by mass or volume flow rates since both of them are related to the density of a material. In the equation m=Q x p, Q is the volume flow rate while mass is m.
The Five Different Kinds of Flow Meters
There are several kinds of flow meters, depending upon the use and the design, materials, and fluid type of the meter. However, there are five main types of flow meters, which include:
1) Differential Pressure Flow Meters
These meters measure the differential pressure when the liquid's flow is related directly to the square root of the produced differential pressure. These have both primary and secondary components as well. The primary component creates a change in the overall kinetic energy by using a pilot tube, an orifice plate, a balanced flow meter
, a flow nozzle, or several venturi flow meters. Then, the secondary component takes measure of the differential pressure to give the signal. These kinds of pressure meters are about twenty percent of overall flow meters, most common in the gas/oil industries. Other industries that use differential pressure flow meters are beverage, pharmaceuticals, paper, mining, HVAC, and chemical application
2) Positive Displacement (PD) Flow Meters
PD meters measure the volume in an area filled with liquid, push the liquid ahead, then fill it again. This calculates the amount of liquid that was transferred. Instead of other meters that measure another element and then convert the numbers into the flow rate, these meters measure the actual flow of the fluid in the meter. Here, the output is directly related to the liquid's volume that comes through the flow meter. PD meter types include oval-gear flow meters
, rotary vane type meters, piston meters, nutating disk meters, and others. These are the most accurate types of flow meters, most often used in transferring fluids and oils such as hydraulics or gasoline. They are also used in-home for gas or water applications.
3) Velocity Flow Meters
These flow meters measure the velocity of a stream of liquid to determine the volumetric flow rate. They are less sensitive if and when the Reynold's number of a certain liquid is greater than 10,000. These kinds of flow meters include paddlewheel, turbine flowmeter, vortex shredding flowmeter, sonic/ultrasonic, and electromagnetic flow meters
4) Mass Flow Meters
These meters are best used in processes related to mass since they measure the force that is created from mass' acceleration. In detail, the force is noted as the mass' movement over a unit of time passing, rather than the volume over a unit of time. Mass flow meter subtypes include thermal dispersion flow meter
and Coriolis mass flow meters. The most common uses for these meters are ones related to chemical and gas industries. Other areas of use are power, mining, pharmaceuticals, and wastewater.
5) Open Channel Flow Meters
Open channel meters measure liquids within open channels like weirs, flumes, or v-notches. These are overflows, which are dam structures, which let a small or especially concentrated liquid free-flow dependent upon the structure's size and shape. Open channel flow meters allow flow rate readings to be measured. The most common uses of these flow meters are within free-flowing liquid settings, like rivers, streams, sewers/wastewater systems, or irrigation waterways.