DC manometer

[Ole Anderson]

I see that some folks use a simple plastic "U" tube with water to read losses across the filter, in lieu of an expensive gauge. But has anyone added a second one on the inlet side of the DC to measure actual total static suction, so in combination with the DC's fan curve, one can tell how much air is actually flowing? Seems like it would be useful to answer some of the questions (arguements) about the actual effect of choking the flow with undersized pipe, or machine connections. Might yield some interesting info about how a particular setup, or combination of simultaneous open blast gates, actually is affecting the flow. I suppose you could accomplish the same with an anemometer (velocity) meter, but that would take some cash outlay. For example, I am wondering if I left my gate open (or didn't even install one) on my 3" TS top feed, what would the affect be on the flow to my other machines?

[Jerry Bruette]

The manometer or a magnahelic(sp) measures the differential pressure across the filters to indicate if they're getting plugged or not. You could go to the Dwyer website and see if they make a gauge for your purpose.

[John Lanciani]

http://ecx.images-amazon.com/images/I/41kmtKRcWQL._SL500_AA300_.jpg

About $80 from Amazon. I use mine exactly as you describe; on the inlet side to calculate airflow (using the appropriate fan curve) and on the outlet to measure filter SP so that I know when to clean it. It also comes in handy to set the draft on my pellet stove.

[Anthony Whitesell]

for clarification, differential pressure as in the difference in pressure between the inlet of the filter and atomshperic.

You could use one before the fan inlet to measure the SP loss of your duct work. eBay often has them for sale.

[Ole Anderson]

Man, don't show me those fancy electronic gizmos, now I want one. I was going to just spend a buck for some plastic tubing.