Reply to thread

VacuumLand – Vintage & Modern Vacuum Enthusiasts

Help Support VacuumLand:

I hate to break it to you:   Air is a compressible fluid.  This is a critical piece to your puzzle.  What you are looking at throughout your tests is only half of the picture:  volumetric flow.


For example, 100 CFM of air @ 101,325 Pa is not the same as 100 CFM of air at half that pressure, such as what might be experienced at the head of a vacuum cleaner.  Mass flow rate of air will not be the same between these two cases, and therefore the work performed by the vacuum cleaner per unit time is not the same.


Take a couple of fluid mechanics courses and you will discover that what ultimately matters is the ability for a fluid stream to do work in a given amount of time.  That is all a vacuum cleaner is trying to do, right?  A vacuum cleaner with a higher air wattage--a watt is a unit of work per unit time (J/s), also known as power--has the ability to do more work.  Fact.  This is why it has become the standard measure of vacuum cleaner performance.  Just the same way that a car with more power can do more work per unit time.  Or a heater with a higher power rating can heat a room more quickly.


I am sorry to say that chasing CFM numbers alone cannot fully paint the picture you are looking for.


Back
Top