Exhaust Filter Expectations and Performance

[Don01]

Last year I was sourcing my exhaust filters I had some interesting email discussions with a few suppliers.
The issue was relating to the overall effectiveness of of using spunbond over paper.
The spunbond is easier to clean but the nominal pore size is listed as 1 micron. So you need fewer pleats (sq ft) to deliver the desired flow.
Paper elements are listed as .5 micron nominal pore size, more pleats (sq ft) to achieve the desired air flow.

I went with paper as I thought this whole idea of cyclonic separation, big pipes, optimal velocity and cfm was to get as much of the bad stuff out of the air as possible.

Neither manufacturer convinced me that there was enough justification to go with a larger nominal pore size. My thinking is I can replace elements if necessary, not so with my lungs.
I have not read anywhere that owners of CV products experience an unacceptable amount of filter maintenance. I am assuming that the CV design results in minimal dust being carried through to the filters.
I have a friend near by who built the Pentz design from Bill's plans. He has a commercial operation and builds a lot - a lot of baltic birch cabinents for local industry. He is able to discharge to the outside. The amount of waste behind his shop is incredibly minimal, even considering he has overflowed his dust bin a few times.
I can run my exhaust through a knockout chamber and use the best 3M filtrete element to optimize flow and keep the discharge at less than micron.
Am I off base in my thinking?

Don

 

[McRabbet]

Don,

You didn't provide the dimensions of your knockout chamber nor the 3M Filtrete filter element that you are using, but I think you would be hard pressed to come close to the 600 SF of filter surface area with the pair of Wynn 9L300BL filters (Farr style, at $79 each) recommended for a ClearVue Cyclone. The high separation efficiency of the cyclone minimizes the dust passed to the filters to a very small amount and they have 0.5 micron pore size to stopp the most harmful dust particles. They clean easily (if you do not let your chip bin overflow) with compressed air and should last for years. You need to replace your 3M filters much more frequently, I suspect and thye aren't cheap.

Of course I'm not sure if Wynn ships to Canada or if you have another supplier with an equivalent product. I seem to remember one in a thread here in the past, so you may want to do some searches for them.

 

[Matt]

Wynn Does not ship to canada but we stock them just for you guys in canada. I'd have to agree with rob that you'd probably spend more in 6 months on the filtrete filters than on 2 wynn filters. You could always go with one filter if your on a budget and may have to clean it a little more often. The output of the shop vac actually works better for cleaning the filters than 90 lbs of compressed air (or at least in my experience). It's not the pressure that cleans them but the amount of air....most air nozzles only provide a small stream at about 4.5 cfm while the shop vac will provide 100-200 cfm at less pressure but more than enough to blow through the filters.

Matt

 

[Don01]

I think I did not express my concern and question very clearly.

I have 2 elements from Camfill Farr, I am not trying to cheap out on this aspect of my system. They are actually what is referred to as a HemiPleat Tenkay dust collector cartridge #214455001 (http://www.farrapc.com/products/hemipleat/). The downside to this and any non standard US made element is the cost of getting them here is equal to the cost of the elements.

When I was researching filter elements I contacted 2 notable manufacturers. They both quoted me the standard .5 micron paper blend media and a 1 micron spunbond media option. I was unable to get a satisfactory explanation as to why they would offer the 1 micron pore size when I asked for .5 micron.
The major advantage appears to be greater airflow (obvious), easier cleaning, perhaps longer life.
The major disadvantage appears to be that these spunbond elements are going to pass a considerable amount of dust back into the shop.

I wanted to open this for discussion as there are folks who are going to source their own filter elements, and need to be aware of the pros & cons to element construction. I am glad to see Clear Vue selling the Wynn elements in their package. It makes the whole process much easier.

Don