Whether you work in the chemical processing, water treatment, or any other business where accurate fluid measurement is essential, this article will help you in understanding the various flow meter technology. We'll go over the special advantages, possible drawbacks as well and best uses for each kind of flow meter so you can make a smart decision that maximizes the efficiency of your business.
What is a Flow Meter?
A flow meter is a device that measures the volume or mass of a liquid or gas. Flow meters exist by a variety of names, including flow gauge, flow indicator, liquid meter, flow rate sensor, and so on, depending on where they are used. No matter what, they all measure flow. Open channels, such as rivers or streams, can also be measured with flow meters. In addition, the most useful and diversified flow meters are those that measure gases and liquids in a pipe. Such instruments serve as essential for monitoring fluid dynamics in industrial settings and enable to maintain process efficiency by effectively quantifying fluid movement.
Different Types of Flowmeters
Differential Pressure Flow Meter.
Imagine the freely moving water of a river unexpectedly accelerating when it encounters a variety of stones, causing a noticeable decrease in pressure. This is a natural phenomenon that is similar to how differential pressure (DP) flow meters work.
These devices work by intentionally putting an obstacle into the pipeline. This causes a quantifiable change in pressure, which is then used to accurately calculate the liquid's flow rate by applying Bernoulli's Principle.
There is a direct correlation between the velocity of the fluid and the amount of pressure reduction across this obstruction, ensuring smooth and regular flows.
Volumetric Flow Meters.
One of the most well-known types of flow meters is the volumetric flow meter, which is well designed for calculating the volumetric flow rate of a fluid in a conduit. These instruments provide a precise measurement of the volumetric flow by precisely measuring the amount of fluid that flows through a system over a specified period of time.
These meters are essential for process control and consistent product quality in a variety of industries, including petrochemicals, food and beverage manufacturing, pharmaceuticals, and water treatment.
Mass Flow Meters.
Only measuring volume doesn't always provide the desired level of accuracy. This is where mass flow meters come into play because of their advanced capacity to precisely and accurately estimate the actual mass of fluid passing through a device. These devices do more than just measure volume. They go farther to measure the fundamental characteristics of the flowing materials, including gases and liquids.
Velocity Flow Meters-Vortex Flow Meters.
The velocity through the meter has a direct relationship with the output signal. Even when viscosity varies, velocity flow meters remain stable, especially at high Reynolds numbers. Vortex meters work on the idea that when a non-streamlined object is placed in the middle of a flow stream, a sequence of vortex are shed in addition downstream of it. The frequency of vortex shedding is directly related to the velocity of the liquid flowing through the pipeline.
The flowmeter has three basic components: a bluff body strut installed across the bore, a sensor that detects the presence of the vortex and the conditioning with transmitter which generates an electrical impulse signal then amplify it and finally transmit it to destination.
Open Channel Flow Meters.
These devices monitor liquid movement in spaces free of overhead restrictions, including channels, flumes, weirs, and partially filled pipelines, by using level sensors without making physical touch.
Like a professional surveyor charting every rise and dip in their environment, an open channel flow meter precisely measures the waterway's structure and depth.
Ultrasonic Flow Meters.
Ultrasonic flow meters are very skilled in measuring fluid movement in the subject matter of acoustic vibrations in liquids using an effective and easy to use method.
The fundamental working principle utilizes the use of an ultrasonic signal's frequency shift (Doppler Effect), which occurs when the signal is reflected by moving gas bubbles or suspended particles.
Time-of-Travel (or transit) meters and Doppler meters are two categories of ultrasonic flow meters.
Ultrasonic Sensor: What you should know
Electromagnetic Flow Meters (Magmeter).
An electromagnetic flow meter, or magmeter, measures the flow rate of liquids that are electrically conductive using the electromagnetic induction principle.
Positive Displacement Flow Meters.
Positive displacement flow meters are unique among flow meter types because of their methodical approach to fluid flow measurement. These devices operate by dividing liquids into precisely determined amounts and moving them forward. Each divided part is counted by a connecting register. Positive displacement meters are suitable for measuring viscous liquid flows or for applications requiring a simple mechanical meter system. Followings are some types of these flow meter.
Turbine Flow Meters
Turbine meters are widely used for accurate liquid measurement applications. The unit is made up of a multiple-bladed rotor installed on a pipe that runs perpendicular to the liquid flow. The rotor rotates as the liquid flows through the blades. The rotational speed is directly related to of flow rate and can be measured using a magnetic pick-up, a photoelectric cell, or gears. Electrical pulses can be counted and totalized.
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| Turbine Flow Meter (Ref:-enelsan.com) |
Orifice Flow Meters
Orifice flow meters are the most common liquid flow meters in use today. Basically its a type of differential pressure flow meter. An orifice is just a flat piece of metal with a specific-sized hole bored into it. The most common form of orifice used is concentric, but eccentric, conical (quadrant), and segmental designs are also available.
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| Orifice Flow Meter |
In practice, the orifice plate is placed in the pipe between two flanges. The orifice, which serves as the primary device, constricts the flow of liquid, resulting in a differential pressure across the plate. Pressure taps on opposite side of the plate are used to determine the differences. The main advantages of orifices are that they have no moving parts and their cost does not grow significantly with pipe size.
Venturi Flow Meters
These flowmeters contain no moving parts. They can be fitted in large diameter pipes with flanged, welded, or threaded end fittings. Four or more pressure taps are often installed with the unit to average the observed pressure. Venturi tubes are compatible with most liquids, including those with a high solids concentration.
A venturi tube is a type of pipe with a tapered entrance and a straight throat. As the liquid moves through the throat, its velocity rises, resulting in a pressure difference between the inlet and output regions.
