Filtration revisited

[MikeK]

That's so strange as they were able to supply me with a larger one than that. Perhaps it is simply filter material dependant.

On the subject of the size of the filters, I thought it quite interesting that the Harvey G700 extractor machines only have tiny filters with an apparent material area of just 7m2 or 75 square feet total, not each. I shan't get into the ups and downs of the machine itself but that one point did stand out to me.

I seem to recall the Nordic Air (or maybe it was the DJN) website stating any filter material could be used in any of the available configurations. If you have a larger filter, maybe there's some light at the end of the eventual replacement tunnel.

I didn't perform any analysis on the filters when I built my system. Dick Wynn, owner of Wynn Environmental, recommended one 35B222NANO filter for those upgrading their 1.5HP DC systems. My system has a 3HP motor and I had the space for more filters, so I designed the plenum for two filters. I didn't want the filter to be a limiting factor in air flow.

There is so much filter area that I can't feel any air coming out of the filters with the system operating. However, there is plenty and I have to move fast when I cover the filters with large plastic bags when I test the manometer connected to the plenum. The first bag is blown apart or blown off the filters within a few seconds, but this is long enough for me to see the change in static pressure.

 

[DBT85]

Interesting @MikeK. In your position I might be tempted to try and test airflow and static pressure with one of the holes in the plenum blocked off just to see if it makes any difference at all. More filter will always be better of course, but also more expensive to replace should the time come.

At some point I'd like to get a merv15 or similar for mine. This one is ok but as you mentioned before in this thread, its not as good down at the low end as I'd like.

 

[MikeK]

Interesting @MikeK. In your position I might be tempted to try and test airflow and static pressure with one of the holes in the plenum blocked off just to see if it makes any difference at all. More filter will always be better of course, but also more expensive to replace should the time come.

At some point I'd like to get a merv15 or similar for mine. This one is ok but as you mentioned before in this thread, its not as good down at the low end as I'd like.

That is in my plan when I get ready to change over the cyclone and before I remove the existing plenum. If I can work with one filter, then I will immediately have a backup (assuming it doesn't degrade over time). This will also allow me to build a smaller plenum.

 

[DBT85]

That is in my plan when I get ready to change over the cyclone and before I remove the existing plenum. If I can work with one filter, then I will immediately have a backup (assuming it doesn't degrade over time). This will also allow me to build a smaller plenum.

Please do share your results if you remember when the time comes. Mines a 3hp motor with a 300mm open impeller (rather that one with 2 side walls and blades in between) so there is scope to increase my own setup one day.

I say that while I have 3 ongoing workshop projects that are in varying states of completion as other things keep coming up!

 

[BB Turning]

Still can't get a hold of a 480mm filter to fit my dust extractor although 320mm seem readily available. In another thread, a member said he created a 'donut' to allow (I assumed) a larger filter to fit his extractor so I'm wondering what would be the implications of creating a "step-down donut"?

Hi a quick question, I have been looking for a 320mm cartridge filter for the last two days and can't find one. Could you tell me where you seen them please.
Shay

 

[Inspector]

Hi a quick question, I have been looking for a 320mm cartridge filter for the last two days and can't find one. Could you tell me where you seen them please.
Shay

Two suppliers in the third post of this thread. I just did a quick search of Industrial Cartridge Filters and found at least half a dozen more. Play with variations and you'll find more, perhaps even local to you.

Pete

 

[BB Turning]

Two suppliers in the third post of this thread. I just did a quick search of Industrial Cartridge Filters and found at least half a dozen more. Play with variations and you'll find more, perhaps even local to you.

Pete

Cheers Pete, very much appreciated.
Shay