What is a Mass Flow Controller?

Introduction

If you are in charge of a laboratory or industrial setting, you may be familiar with the phrase thermal mass flow meters.  That is the place where it is most relevant, after all.  There are several ways they are used in this context, some of which I will be discussing in this article.

However, if you are unfamiliar, I do recommend you look at a page such as this one for some important background details.  This will help you to understand the rest of what I will be covering.  It may not seem relevant, but these concepts are surprisingly important in regard to manufacturing, so I do recommend that you follow along if that is something you are involved with.

What is Thermal Mass?

Let us begin by returning to the basics.  Thermal mass is a material’s capacity to absorb heat.  In addition to that, it is also a measure of how well it stores it and releases it.  A concept in conjunction with this is that of thermal lag, which is a measure of a materials’ rate of heat release.  Generally speaking, if there is a higher mass, there will be a longer lag period.

Where it gets a bit more complicated is that when something has a higher mass and lag time, it is called “thermal mass” – thus, the phrase can be referring to two different things at the very least.  The ability to differentiate between the two is invaluable.

Why is this Concept Important?

I touched upon it briefly above, but the main reason that this is important is the variety of applications it can be applied to.  For example, the Teledyne mass flow controller is designed to measure thermal mass in either industrial or laboratory settings, and there are many other items like it that are specifically for this purpose.  It is key to track these levels.

Part of that is because of geothermal energy plants and their increasing popularity as a form of heating buildings, particularly homes.  Of course, other properties can utilize it as well, but many people are particularly interested in it as a form of sustainable and affordable energy for our houses.

So, understanding the different masses of the materials we build with, for example, can be beneficial.  Concrete and bricks often have a long lag period while timber or lumber has a low mass and thus a short lag period.  Once you know what is better for a certain climate, you can save on your energy bill!

What are some examples of this?  Well, the biggest one is the difference in construction in hot climates versus cool ones and comparing that to how it works in mixed environments.  So, in most cases, lower mass is preferred in hot weather and higher mass is preferred in cold weather.  When the temperature frequently fluctuates, typically higher is preferred as it can help regulate temperature just a bit better, especially if air conditioning is involved.

If you want some specific measurements and figures, you can look at this resource to find some: https://www.yourhome.gov.au/passive-design/thermal-mass.  It covers some of the basic materials that we often run into but is not an all-encompassing list.

Uses for this Concept

Something that not many of us consider is its application in the pharmaceutical industry.  I mention it first because I find it one of the more fascinating and important uses.  Specifically, we can apply these concepts towards batch bed fermentation.

In most cases, this process of fermentation varies significantly between each batch.  That is largely due to the parameters it operates under, which are different depending on which version of fermentation you are using.  Knowing how to control or at least navigate the thermal mass levels when performing this can help to limit the extreme variations.

The other main way I will cover today is in air sampling.  You see, you must know the mass of a compound before you can test it for potential contaminants, and this is the case for air, even if we may not think of it as a compound.  So, when a sample is collected, the proper equipment to measure its mass must be used, or there is a chance that the findings will not be accurate.

So, the main purpose here is to do three things.  First is allowing for continuous and accurate analysis of a material.  Second is to create a flow signal, thus meaning there can be proper documentation.  Third is the ability to control the flow of a given sample, even when the pressure or temperature is changing.

Conclusion

If all of this was a bit confusing, I understand.  I would recommend checking out some of the resources I provided if you are keen to learn more about this topic.  That is especially true if you are involved in any of the industries I mentioned!