Dust Collector Filter Gauge Reading

[Larry Frank]

I recently installed an Oneida Super Dust Gorilla 5 hp cyclone. It has worked very well but I have been doing some testing to determine the performance curve and the typical flows and static pressure in my shop.

I am currently doing the testing on the 8" inlet and got a performance curve very close to the one on the Oneida site. I will be posting this data in the near future as I get it into a better looking format.

The unit has a HEPA filter rated at 99.97% down to 0.3 microns and is rated MERV 16+. I measured the pressure on the output side just before the filter as I want to put in one of the filter gauges that have been discussed. Using a Digital gauge, I measured 3.38 inches water with it. I also check using a simple plastic u-tube device and got the same thing.

I thought that this was high so I cleaned the filter with compressed air per the instructions and did not get very much dust at all. I visually examined it and it was pretty clean. ( I have only run about 4 bins full of chips through it that came from the planer and table saw.)

The readings seemed pretty high but I wonder with a filter like this if this is normal? Does anyone have a similar filter on their dust collector and what type of readings do you get?

[Ben Rivel]

Can offer you any data, but was curious, what digital gauge are you using?

[Larry Frank]

I used an UEi 151 digital manometer. I also used a homemade plastic tube "u" shape water manometer. I got the same thing with both.

I tested it with the 8" duct wide open and about 1600 cfm measured with a Dwyer 471 digital hot wire anemometer.

The digital gauges were borrowed from John Lanciani who has posted several times about dust collectors.

[Ole Anderson]

Just checked my 2 hp SDG with a smaller version of the same filter. Running just over 1000 cfm, I am reading 2.5" on my filter with a 6" and 5" gate open. I am sure the filter needs cleaning. Usually about 1.3" after cleaning, I wish I had checked it while still new. I final clean my filter outside with a leaf blower.

[Larry Frank]

I posted about the high filter pressure readings that I found when testing my Super Dust Gorilla. This really bothered me as I knew the filter was clean but the reading was high. After thinking about this, I did some more tests today. I ran a performance curve for my dust collector by measuring the air velocity at various levels of static pressure. In addition, I also measured the filter pressure at the same time and came up with the data in the following graph.

SP vs Filter.jpg

The data shows that as the static pressure goes up (and air flow goes down), the filter pressure goes down. I guess that it makes sense that as the airflow increases the filter has to pass more air through it and the pressure goes up.

It also suggests that for each dust collector and filter, it is a good idea to monitor the filter pressure at the same operating conditions such as having the same gates or similar gates open. For my dust collector, if you looked only at the filter pressure at high flow, it appears that the filters are dirty. While if you look at it with low flow, the filters look like they are fine.

[John Lanciani]

That looks great Larry. As for the filter, you are correct that with less airflow through the filter there is less back pressure. I have a Magnahelic on my filter and I open all of my blastgates from time to time to get a reading of the backpressure (and filter status) at max airflow.

One question, did you take an amp reading at max airflow? I'm curious how much of the 5hp is actually being used. My V3000 does not quite hit 3 hp running wide open.

To all; if anyone is interested in borrowing my test equipment that Larry is currently using (manometer, hot wire anemometer, and ammeter) just send me a PM in the next couple of days and I'll have Larry forward them to you instead of sending them back to me. They ship nicely in the game sized flat rate box, so it's just under $20 each leg of the journey.