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SG1911
Stranger
Registered: 11/26/16
Posts: 2
Last seen: 7 years, 1 month
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A question about my old but never used HEPA filter
#23883925 - 12/01/16 08:57 AM (7 years, 1 month ago) |
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I purchased a HEPA filter at least 15 years ago with the intention of building laminar flow hood. Life got in the way and the filter languished unused and sealed in a plastic bag for all those years. I now have the time and inclination to put it to use and am trying to understand its characteristics in order to decide on an appropriate blower to use with it.
The filter is labeled Hefco MicroFlo H1823A00-0YYY2Y0Y4 It's 18 X 24 X 5 7/8" 99.99 %
Resistance is listed as .0005/.78 inches W.C. I'm struggling to understand the meaning of the resistance value. I was expecting to see something like .78 inches of W.C. at some specific cfm of flow rather than the value listed.
Hefco no longer seems to be in business at least as far as I've been able to ascertain.
Any ideals on the
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PirateSwazey


Registered: 12/12/12
Posts: 2,993
Loc: Here, Now
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Re: A question about my old but never used HEPA filter [Re: SG1911]
#23883940 - 12/01/16 09:03 AM (7 years, 1 month ago) |
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300CFM @ .78 plus an extra .2 for prefilter.
Search Grainger for a blower that moves 300CFM @ 1" SP.
It is okay to go a little over and stack prefilters or add a speed controller.
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SG1911
Stranger
Registered: 11/26/16
Posts: 2
Last seen: 7 years, 1 month
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Re: A question about my old but never used HEPA filter [Re: PirateSwazey]
#23884089 - 12/01/16 10:09 AM (7 years, 1 month ago) |
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Quote:
PirateSwazey said: 300CFM @ .78 plus an extra .2 for prefilter.
Search Grainger for a blower that moves 300CFM @ 1" SP.
It is okay to go a little over and stack prefilters or add a speed controller.
Thanks for the reply PS. I'm really most interested in understanding the resistance rating on the filter. The .0005/.78 inches w.c. It appears you're assuming that there is a static pressure of .78" at a flow of 300cfm through the whole filter but I'm not entirely certain that's the case though it would seem typical of filters of this type. Put another way, what is the .0005 referring to?
I do already have a Dayton blower rated at 580CFM at a static pressure of .8" but it shows not values out beyond this level. I assume it may well over tax the fan if installed in a higher static pressure situation.
Cheers,
SG
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PirateSwazey


Registered: 12/12/12
Posts: 2,993
Loc: Here, Now
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Re: A question about my old but never used HEPA filter [Re: SG1911]
#23884182 - 12/01/16 10:49 AM (7 years, 1 month ago) |
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That fan may work, if you can find a model number you may be able to find a chart for its output.
For laminar flow you want 100CFM blowing out the front of the filter. The static pressure of your filter is .78" W.G. (water gauge - standard measurement for resistance in HVAC). I am not sure what the first smaller number is, but it is too small to be the number you're looking for.
I have the formula for finding laminar flow in the link in my signature below if you want to see where u got the 300CFM @ 1" SP from
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