|
 Some of these posts are very old and might contain outdated information. You may wish to search for newer posts instead.
|
 JSshroom
dont be paranoid, just aware
Registered: 06/16/05
Posts: 825
Loc: I love that spore drop
Last seen: 5 months, 19 hours
|
 flowhood filter q's 
#8902831 - 09/09/08 04:04 PM (15 years, 7 months ago) |
|
|
Ok I am looking at buying a filter with these specs.
Tested at .003 leakage making it 99.997% effencey 1.4 static pressure . Made May 2002.
it is 24x24x11.5 inches. I have read that 1 static pressure is ideal but FP sells their flowhoods rated at .8. I dont understand this whole static pressure thing. does it just mean it will take a bigger blower?
|
 sandman420
Saint PP
Registered: 06/17/04
Posts: 5,384
|
Re: flowhood filter q's [Re: JSshroom]
#8903035 - 09/09/08 04:50 PM (15 years, 7 months ago) |
|
|
static pressure is the resistance the filter has with the air blowing through it. More resistance requires a more powerful fan. Your filter is 12" thick so it has much more resistance than a 6" thick filter, which most flowhoods use. I would look to getting a brand new filter, who knows what that thing has been through for 6 years.
|
JSshroom
dont be paranoid, just aware
Registered: 06/16/05
Posts: 825
Loc: I love that spore drop
Last seen: 5 months, 19 hours
|
Re: flowhood filter q's [Re: sandman420]
#8903183 - 09/09/08 05:17 PM (15 years, 7 months ago) |
|
|
I have been speaking with the vendor and he said it is still in the box, and its new. Do filters age and become useless?
|
JSshroom
dont be paranoid, just aware
Registered: 06/16/05
Posts: 825
Loc: I love that spore drop
Last seen: 5 months, 19 hours
|
Re: flowhood filter q's [Re: JSshroom]
#8903328 - 09/09/08 05:48 PM (15 years, 7 months ago) |
|
|
also does anyone have a preferance of squirrel cage vs inline fan. I dont care about the cost but I am building this thing and its gonna be a lot heavier with the additional weight of the pre-filter housing.
Also if I do just build it out of a single housing with inline fan. Can I put recessed handles in the sides of the plywood. I work for a custom case manufacturing plant so I have access to lots of neat stuff. The handles would be pop riveted with ten rivets each and then heavily siliconed over the back. I could also cut a piece of wood and glue it over the handles inside the box, and screw that in from the inside towards the exterior of the box? Which would help to seal the holes drilled for the handles. I could also use a handle that just rivets into the housing, but they are not as nice
|
RogerRabbit
Bans for Pleasure
Registered: 03/26/03
Posts: 42,214
Loc: Seattle
Last seen: 1 year, 1 month
|
Re: flowhood filter q's [Re: JSshroom]
#8903887 - 09/09/08 07:32 PM (15 years, 7 months ago) |
|
|
You can recess the handles to make it look better. Build a plenum at least 6" thick on the back side so the blower has an area to pressurize. A larger plenum will help to ensure laminar flow. That means your flowhood will be at least 18" thick.
Use a squirrel cage blower. What that 1.4" of static pressure means is that when they pressurized it(the plenum) to that amount, the flow in cfm was what was stated in the specs, which you didn't post. You can easily operate it at a lower static pressure, but the flow will be lower than stated in the specs.
24" X 24" is four square feet. In a perfect world with no friction and 100% efficiency, a 400 cubic feet per minute fan(cfm @ 1" static pressure) would deliver 100 linear feet per minute in air speed leaving the face of the filter, which is what you want. Since we don't live in a perfect world, and no fan is 100% efficient, I'd suggest a blower in the 500-600 cfm range. Make sure it's rated at that cfm @ .8 to 1.4" of static pressure. Most grainger.com motors are rated at .8" static pressure.
If you get a deal on one that's slightly larger and the flow is too much, you can always block off part of the intake, or even stack two pre-filters together to cut down on the flow. Another option with AC motors is to get a motor speed controller, which can be found online for under $50. However, if you get a motor rated 500 to 600 cfm@.8 static pressure, I can't imagine it flowing too high. It would probably just develop more static pressure, since your filter is so thick.
Anno has some good info about flowhoods on his website that you might want to check out.
RR
--------------------
Download Let's Grow Mushrooms
semper in excretia sumus solim profundum variat
"I've never had a failed experiment. I've only discovered 10,000 methods which do not work."
Thomas Edison
|
JSshroom
dont be paranoid, just aware
Registered: 06/16/05
Posts: 825
Loc: I love that spore drop
Last seen: 5 months, 19 hours
|
Re: flowhood filter q's [Re: RogerRabbit]
#8904353 - 09/09/08 09:08 PM (15 years, 7 months ago) |
|
|
Ok I will use a squirrel cage blower. what is the difference in efficiency between that and an inline blower?
I am not really understanding the plenum. I saw a board in the flowhood on anno's page but it sat in the middle of the inline blower so half was blowing behind the board and 1/2 into the filter side of the box. I looked for threads with pictures but could not find any? 
any help appreciated.
Also I read on someones post that the plenum should be as tall as the filter is thick so that would be like a 11-12 inch plenum leaving a gap of 11-12 inches too the top of the flowhood? If that is correct.
Also when constructing the flowhood I put the filter in against the slats inside the box. Silicone that area heavily. Then silicone around the front of the filter and put on the angle cut aluminum to hold it in on the front side. This should seal the filter in place?
Also when I put the recessed handles in there will be 10 pop rivet backs exposed. I can take a peice of plywood and mark the holes. Countersink 10 holes so the plywood will fit over the rivets and screw that in over the recessed handle further sealing it. Does this sound like a good idea.
I am going to be using laminated plywood. The laminate on the outside of the box. Should I be painting the inside with kilz or something or just let the wood be natural?
So a fan that is rated to blow 600 cfm is rated to blow at .8 or higher SP? I am really confused on this part as anno's webpage also looks like a german conversion to English that is hard for me to grasp right away.
I was looking over the math and it would seem that 4 sq ft x 100 ft per minute = 400 x 1.4 SP = 560 cfm so a 600 would be just a little more powerful.
I am not grasping the rating of SP with a fan. I will also have to account about .2 SP for a pre-filter. so that would make it 400 x 1.6 = 640 CFM and to take it a little over we are talking the 640-750 cfm range? is this correct.
I have more q's but this is enough for now. its all getting jumbled in my head now
|
sandman420
Saint PP
Registered: 06/17/04
Posts: 5,384
|
Re: flowhood filter q's [Re: JSshroom]
#8904410 - 09/09/08 09:18 PM (15 years, 7 months ago) |
|
|
plenum = cubic area behind the filter. It's just a box, with the filter facing out yo, nothing to fancy is required. And then you simply build another box on top around the fan and cover the top with a furnace filter or 2 and that is your prefilter.
|
mushfrog
Stranger
Registered: 03/29/20
Posts: 1
Last seen: 2 years, 4 months
|
|
Hi, I have a HEPA filter rated at 99.97% for 0.3 micron particles that appears to be made of cardboard or something (it is disposable). Would it be worth trying to make a laminar flow hood with it, or should I get a ceramic one? Thank you.
|
|
|
You cannot start new topics / You cannot reply to topics
HTML is disabled / BBCode is enabled
Moderator: Shroomism, george castanza, RogerRabbit, veggie, mushboy, fahtster, LogicaL Chaos, 13shrooms, Stipe-n Cap, Pastywhyte, bodhisatta, Tormato, Land Trout, A.k.a
1,034 topic views. 28 members, 184 guests and 53 web crawlers are browsing this forum.
[ Show Images Only | Sort by Score | Print Topic ] |
|
Threaded
Previous
Index
Next
Kratom Powder for Sale 
Bridgetown Botanicals 
Buy Kratom Capsules
Edit 
Reply 
kilgore_trout
ohmatic
eclipse
KaptKid