Choosing the right mass flow or volumetric flow device

What you should know

Why learning about mass flow and volumetric flow meters is important.

Choosing the right mass flow or volumetic flow device can mean the difference between your process working or working to it's full potential.
Learning about mass and volumetric flow devices will not cost you anything. However, selecting a mass or volumetric flow device without learning about them could lead to a significant cost in both time and money.

What should you know before you buy?

Flow instrumentation does not look very different on the surface, but most devices operate quite differently. It is important to know what you require from a flow device before you ever decide to buy a flow device. There are a number of options and features that differ from manufacturer to manufacturer. At the end of the day, a flow device is a measurement tool. Prior to shopping for a device you should know the following about your own process measurement requirements to insure that you are shopping for the right device:
  • Maximum flow rate
  • Minimum flow rate
  • Gas/liquid temperature
  • Gas/liquid pressure
  • Type of gas/liquid that is being flowed
  • Is the gas/liquid toxic or corrosive
  • Device input and output requirements (analog or digital)
All of this information will be important in helping you choose the right flow device for your process. Different device manufacturers have different specifications for their devices. Some will operate under higher pressure or temperature conditions than others, some respond faster to changes in flow than others and so on.

What makes flow devices different?

Flow devices generally follow one of several principles. Each of these methods has distinct advantages and disadvantages. While one type of device may flow a gas at high temperature or high pressure it may not so very accurately, or vice versa. If high temperature, high pressure and accuracy are all critical elements in your process than it is important to choose a device that adequately meets all three requirements. However, if one is more important than another a device may be selected.
It is also very important to decide early on what features and characteristics will be of most use to you for your particular project. A flow device that comes with a standard display may be of great value if the process must constantly be monitored, but would be of no value if it did not flow the type of gas that you process requires. Some manufacturers include more standard features than others. If you decide on a certain brand of device as it meets the criteria of your process also make sure that you will not have to purchase additional "options" that will make the device compatible with your process. Many manufacturers charge for multiple outputs, digital communication, displays, valve types, seals, fittings, etc. It is important to know what you require and choose a device in which most of these options are standard to keep costs to a minimum.

Understanding specifications

Understanding specs is very important when shopping for a flow device. You will be presented with specification sheets that indicate the physical and operational characteristics of a flow instrument. These spec sheets are designed to describe the operating characteristics of the device. It is important to know what those specifications mean and how they apply to your process or measurement goal.