E-Zine February 2015
Click here to read “Part 1: When Do You Measure Mass Flow”
I’ve often said that if I had to be restricted to only two kinds of flowmeter ever, I would want a magnetic flowmeter and a Coriolis mass flowmeter. Thankfully, those are not the only kinds of flowmeters there are. There is a reason for this.
When you select a flowmeter, after you decide if your application is for liquid, solid, gas or multi-phase flow, and after you decide whether your pipe is full or not, the very next most important cut is cost.
Why is this true? If you visualize all of the possible flowmeters as icons on a screen, and you decide you have a flow that is a liquid, and the pipe is full, you have many ways to measure that flow. There are lots of icons on the screen.
However, if you decide that you only want to consider those flowmeters that cost under US$ 1000, instantly many of those icons vanish. Now you can easily see what you have left, rather than all of the choices.
Now you can sort the remaining icons by pressure, viscosity, temperature, corrosivity and other parameters. You may very well see that you can select one of the sub US$ 1000 flowmeters, and use it successfully. Or, you may see that you can’t get what you want for that cost.
So, you go back and widen the cost window, and more icons reappear.
What this sort of selection process does is to ensure that you do not over engineer the flowmeter application. Sure, the Coriolis mass flowmeter works fine for all of the applications the pharmaceutical plant uses them on, and it will also measure that water application quite well. But in most cases, the direct measurement of mass throughput isn’t required. It just isn’t necessary, and the additional cost of purchasing and installing a Coriolis mass flowmeter isn’t justifiable.
So, when do you need to measure mass flow?
Click here to read “Part 3: When Do You Measure Mass Flow”
From Flow Control (July 2002)