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Digital Water Flow Meter: What it is and How it Works

By Naman ModiTwitter Profile | Updated: Monday, 15 February 2021 21:22 UTC
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Digital Water Flow Meter
Digital Water Flow Meter

When measuring liquids, accuracy is very important because it determines the quality of the product. That's why it is why flow meters are needed in water flow systems. A digital water flow meter is a tool used to monitor and determine the flow rate of liquids and gases in various industries. They are available in many types, measuring water flowing through a pipe or an open channel. Fluids also come in different kinds, each having varying density and velocity.

Before choosing the type of flow meter that you want to use, you need to consider your budget, the type of application, and maintenance requirements. A meter's operating principle is the flow meter type.

This post will explore the four main types of flow meters and how they are used in different applications. When you are done reading this post, you will clearly understand which type of flow meter your application demands.

Digital Water Flow Meter Types and Their Applications

1. Mechanical flowmeters

The mechanical flow meter is the most cost-effective liquid flow meter in the fluid measurement industry. Being cheaply available makes it the most commonly used water flow meter in the fluid measurement market. It measures water using a turbine and a propeller. The turbine comes in two designs: shunt and paddlewheel. When measuring flow rate, water flows through the pipe and rotates the piston or turbine.

The pressure of the water flowing through the pipe determines the rotation speed. Volumetric flow is directly proportional to the rotational speed of the blades. They are quite affordable and are used to measure clean water and other clean liquids with no debris that can block the rotating blades. These flow meters are subjected to regular maintenance, which reduces their lifespan. They are also ineffective when measuring the flow rate of low-pressure liquids. Denser liquids are also not effective with this type of flow meter.

2. Vortex Digital Water Flow Meter Types

Vortex shedding is the principle that governs the flow rate of liquids in this type of flow meter. When moving through an obstacle, water creates what are called swirls and vortices. This produces a frequency output from side to side flexing of the sensor tab. The volumetric flow rate relates directly to the output.

The multivariable types of vortex flowmeters measure up to five processes with one process connection. These valuables are temperature, mass, volumetric flow, pressure, and density. Insertion vortex flow meters are ideal for larger pipes since an operator had to insert them into the pipe to measure flow rate. A retractor is used with a hot tapping in the measurement process.

3. Ultrasonic flowmeter

Using ultrasound, the flow rate is measured by the speed of the flow with an ultrasonic flow meter. Unlike other flow meters, the ultrasonic flow meters measure flow rate without contact with the fluid. A transit-time ultrasonic digital water flow meter is used to measure signals transmitted in the direction of the flowing fluid downstream.

The fluid also produces another signal that flows upstream, then sent back to the flow meter. The time taken by the sonic pulse to travel downstream is directly related to the time it takes for the sonic pulse to travel upstream. The volumetric flow rate in the pipe is calculated by the velocity gotten in the ultrasonic meter.

When measuring flow from large pipes, clamp-on ultrasonic meters are quite effective. As an operator, you can install them in many applications. Since this type of liquid flow meter doesn't come into contact with the fluid, it measures flow rate by shooting sound pulses through the pipe walls.

4. Magnetic flow meter

A magnetic field is used to get the volumetric flow rate of a fluid in magnetic flow meters. The flow rate of the measured fluid is obtained through this method. These types of flow meters use the principle of Faraday's Law of Electromagnetic Induction. This is where liquid flowing in a magnetic field generates a voltage. More voltage is created when the fluid flows very fast.

The generated voltage is directly related to the water movement. Electronics that process the signal provides the volumetric flow rate. Magnetic flow meters are not ideal instruments in custody transfer measurements due to poor accuracy levels. They are also not effective when measuring clean water since there are no ions to measure.


The greatest determinant of which type of liquid flow meter is to be used is the application. As the user, the flow meter's accuracy depends on the hydraulic system you've set up. Consult the manufacturer if you are not sure which flowmeter is appropriate for your application.

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