Intro to Flowmeters - Part 1

Flowmeters are devices used to measure the flow of a liquid or gas within a channel or conduit. The first use of flowmeters was in ancient times when water had to be rationed in order to make the supply last all year and still pull in crops for food. Today flowmeters are used in many other ways than just water rationing, in fact there are thousands of applications where flowmeters are a critical part.

Our dependence on flowmeters is great since they affect so many areas of our society such as commerce, public safety and many other areas. Take for instance the gasoline pump, if it did not correctly measure the amount of gas pumped you may end up with less gas than you what you paid for or possibly more gas. Public safety is often reliant on flowmeters, an example is the coolants in a nuclear power plant. If the plants flowmeters did not work correctly there may not be enough coolant delivered and the plant could blow up.

Using the right tool for your application is critical and with flowmeters it is no different. It is important that you have an understanding of at least the basic types of flowmeters and how they are used. Not all flowmeters work the same or will fit all applications. An example is the mechanical flowmeters will affect downstream pressure and if your application cannot tolerate this then an ultrasonic flowmeter may be a better choice.

Each type of flowmeter will have its own operating specifications and within each type there will be different models that have different requirements. Some of the first things you need to know before choosing a flowmeter are about the substance you will be measuring. The type of substance, viscosity and other details are all-important to your choice. Where the flowmeter will be used is also important, such as the minimum and maximum temperature, expected flow rate, atmospheric pressure and more. Besides the above bits of information you will also need to know what type of data you need and if the flowmeter will report to other components within an elaborate system.

Flowmeters rarely stand alone in how they are used. Most often a flowmeter is part of a complex system that can include flow control devices, alarms and flow computers. Today's automobile is a good example of this. Fuel and air must be mixed in order to have a combustible substance to ignite in the cylinders. Today's cars use a flow computer of sorts to manage this and to set off alarms or warning lights if things are not going as planned.

The purpose of this 3-part article is to give you the most basic information about flowmeters. This first section is to introduce you to how they are used and their importance to us. The next two sections will look at specific types of flowmeters including mechanical flowmeters, differential pressure flowmeters, electronic and magnetic flowmeters.