furnace blower?

[rocketbob]

Hi all,

I have a stalled PTS flowbench project. Built the cabinet but never did get around to ordering the vacuum motors.

I'm curious what you would think about using a discarded but perfectly function furnace blower to power the flowbench. I have two of them laying around, perfectly functional. Thinking that I could use a VFD on them. Thoughts?

Thanks,
Bob

[Tony]

Bob, the problem will be that a typical furnace blower will usually not generate anywhere nearly enough air pressure to be useful in a flow bench.
They will sure flow plenty of air, but the developed pressure is just not there.

Whatever you use will need to generate significant airflow when working at around 44 inches of back pressure.
You could test those blowers to be sure, but the chances are they will only be able to generate just a very few inches of pressure when measured with a simple U tube water manometer.

If they have three phase motors, a VFD will certainly make them run faster and generate a much higher pressure, but that depends on the pressure you are starting from at the original design 50/60Hz running speed.

Furnace blowers only have to work against normal heat exchanger and flue back pressures, which is never very high.
Therere are not a lot of common blower types around that can reach 44 inches, it quite a high pressure.

[rocketbob]

ok makes perfect sense.