FlytrapCare Carnivorous Plant Forums

Alright folks, I've been inspired to build a laminar flow hood. After years of doing TC in a ten gallon aquarium I am finally going to upgrade the facilities.

Here's what I have ordered: (All ebay)

Blower motor: http://www.ebay.com/itm/221332105204?ss ... 1423.l2649
Filter: http://www.ebay.com/itm/331105106736?ss ... 1423.l2649

Now the filter isn't designed for a laminar flow hood type application. It is a clean room air filter. So it can pass large amounts of air with a relatively low resistance. As such I will be coupling this filter with a couple of 3M filtrete allergy type filters to increase the static pressure to "laminarize" the flow. Also, in my design I am leaving about 9 inches from the back of the filter to the back of the box for plenum, just to get a large pressurized volume to help achieve laminar flow.

The box will be made out of 5/8 MDF and have 1/2 inch x 1/2 inch square polar dowels at the corners to fasten it together.

So far my rough dimensions will give me a 13" working depth, with a 24" by 24" cross section. It'll be like working in a palace compared to what I am used to. I'll post pics as things arrive and update this thread with build progress.

I am very excited about this project. Also, I wanted to dump my build progress on a non-"medicinal" mushroom forum. Since all of the really good build projects seem to be documented on legally questionable websites.

Neal

Looking forward to watching this project progress!

Following this progress !

I will probably be in your shoes in 2-5 years, so I look forward to following your progress. Best of luck!

Wishing you much success! I will certainly be watching this thread. I will be starting one in a couple of weeks if my filter ever gets here (long story).

Hey Neal,

I'm working on an almost identical project. The only difference is I purchased the AstroCel I with the metal enclosure for a few dollars more.

Let me know how you make out with your build.

I think we were probably looking at plans on the same "medical"-mushroom site but I found this information helpful too:
http://www.solutionsforair.com/dayton_c ... entals.pdf

And I'm guessing you've seen this site as well:
http://www.orchideenvermehrung.at/english/index.htm

I wish there was a more comprehensive spec sheet for these old AstroCel I. A resistance vs flow curve would be nice.

Ryan

Whew. Motor came in on the Tuesday, 18th. Filter came on the Friday 21st. Lumber purchased Friday the 21st. In-law's garage -- 22nd and 23rd. It has been a good weekend.

I've attached photos, though I didn't take as many as I thought.

Okay some deltas from my original plan, of course.... What would a home built project be with out those?

The wood is 1/2 ply. These are joined to each other with 3/4 square dowels and #8 1" screws. There is wood glue on some components (at the bottom) and some places, like the top, I didn't glue, just in case I wanted to get in there for some sort of maintenance.

Some dimensions:

Bottom: 24"x36"
Top: 24"x36"
Sides: 25"x36"
Back: 25"x25"

For the blower case, it is just a box that was built to hold a 16 x 20 prefilter and it is twelve inches tall. I think it is 23" x 18" and there is a top piece of the same dimension with a cutout that holds the prefilter. There is caulk on most joints, especially the back. Oh and some weather stripping around the prefilter.

The recessed lights are cheap ten dollar jobs. I chose those instead of a plexiglass top for ease of construction.

I have 13" of workspace to the front edge of the filter. The filter is 11.5" deep and there is a 1" filtrete 1900 filter behind it facing the plenum. This leaves about 9" of plenum, which should be enough to give the air enough chance to stabilize and build pressure for laminar flow. (This bit of plenum advice came from a "medicinal" mushroom website forum)

I wired the motor for the low speed setting and it generates too much flow. So tomorrow I am headed to Lowe's to get a Filtrete 1900 or 2200 filter for the prefilter and some duct tape/cardboard to restrict the flow. In hindsight I should have gone with a 12" x 12" prefilter, but I didn't know how much flow I would be generating.

I am a bit tired and I may come back to edit this post later.... but for now enjoy the pictures.

Oh, I am going to get a piece of glass cut for my work area, probably two and stack them.

Neal

Tweebs,

Yeah I couldn't find a detailed pressure vs flow chart. My filter passes a 1000 CFM at .7" H2O according to the test sticker. It is also 99.986% efficient, which I am hoping is good enough. Though, the addition of the filtrete 1900 filter is rated (or at least advertised) at 94% of particles larger than 0.3 micron. This should contribute .1 to .2 inches of water column to the pressure.

So tonight I am headed to lowes to get some more restrictive prefilters to reduce the flow to a suitable level. These filters should be of the 1900 or denser variety, plus I will duct taping two or three together. Should knock out much more nasties.

What blower did you select? In hindsight given the copious amount of flow that I have, I would have selected a 12V DC motor to make speed control easier. I have a PSC motor and I think I can use a current limiter to reduce the torque (therefore speed) and that can help. But apparently this type of motor needs a variable frequency output control device which is ridiculously expensive. I think I am just going to go with cardboard and lighter test for flow.

Neal

The project looks good! I'm sure you're itching to use it!

If my quick math is close you would only need 400cfm with a 2x2 filter @ 1.0 wg, so since yours is rated @ 1000cfm @ .7 wg you won't need much of a blower at all. I noticed that from your original post, but you had already ordered or I would have made some suggestions. If you can't get it restricted down enough with the filters I believe I've read some people have used fan speed controllers like you would use on a ceiling fan (just don't use a light dimmer).

Yeah, I didn't have a good feel on the pressure profile of the filter. So I overbought. I bought two filtrete 1900s and duct taped them to the existing filtrete 1000 filter. so I have 3 inches of prefilter. This did not do much to impede the flow. So, I have cardboard on the intake to limit the flow now. The piece of glass is in it now, and it looks awesome. I am going to make up some 100% MS no ppm and just run some quick confidence tests.

Neal