DIY Home Laminar Flow Hood ideas
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- Опубліковано 21 жов 2024
- Having seen various laminar flow hood concepts that have varying degrees of appeal. Here are my concerns and concepts on how to keep it inexpensive and effective.
I look forward to your comments and creations!
I love your video.
You watched other people's tries at making a super cheap air filter/"flow hood", observed what went wrong and understood why and then essentially reinvented the classic regular laminar flow box (often called laminar flow hood in hobby mycology).
In a proper expensive laminar flow box they use a thick HEPA Filter in the quality H13 (99,95 -99,99%) or H14 (99,995-99,999%), packed in a box with enough empty space behind the filter to disperse the pressure evenly as you explained it. And then they have a second box on top, that contains a strong centrifugal fan to blow air into the lower box and a pre-filter at the air intake which protects the expensive HEPA and the fan from regular dust.
The most important thing to actually achieve laminar flow and not just clean turbulent air is matching the flow rate of the fan to the filter you use. Here's a good video I found for doing the math of matching filter and fan: m.ua-cam.com/video/cDaJW77Wb5Q/v-deo.html
Also I've heard that you should use a filter specifically designed for laminar flow as they have little metal fins to direct the air (but are quite expensive).
Wow, Thank you for your comment and input! I'll check this out!
U give sound advice Master splinter,I 2 am thinking of making a flowhood/still air box...except it wouldn't b a still air box with a flow hood attached would it 😂 .my idea evolves mounting th flow hood to the top of the air box with the intire front open to work under.this vid gives me greater insight tyvm
Spoke with an engineer friend who recommended putting the fan on the side of the box to create a true laminar flow... so it is not blowing directly onto the fan. I asked about some form of baffle and he said that would suffice as well.
Some other thoughts on sterile workplace techniques:
So, a still air box (SAB) works great if you manage to work properly sterile in it, it's cheap and quite easy to make. That's why it's the most common way how beginners have success. Having some soapy wet towels on the bottom of the SAB can trap contaminants that fall down even better and increase success rates a lot.
If you have plenty of money to spend, a proper laminar flow box for ~400-2000$ will do the same thing while allowing for free movement of the arms, that's why all the professionals use it.
In terms of alternatives, there seem to be several options with varying rates of success:
1. Take an unused clean plastic bag and spray the inside with a lot of disinfectant. The take all the stuff you need, spray it down and put it inside. Then, close the bag with a good knot and work on your things from the outside of the bag.
It's almost free, annoying to work with but I've heard it to be sterile enough for some to work.
2. An SAB equipped with an additional air filter blowing in clean air that can only escape through the arm holes.
-> Doesn't work because the air flow blows up all the contaminants that you want to trap at the bottom.
3. Some kind of cheap HEPA air filter with some kind of fan. Maybe also in a box like in your video.
- Using a filter much smaller than the box:
Doesn't work well as you showed because of turbulences from the dead air pockets.
- Air just blowing over the bench but without proper laminar flow and without a box/enclosure:
Probably doesn't work well either because the turbulences will draw in contaminants from outside the airflow.
- Having a non-matching filter and fan but with some kind of enclosure that is smaller than or exactly the size of the filter. This should prevent the turbulent air from pulling contaminants in from outside. The only problem could be that the turbulences pull contaminants from your skin/gloves onto the agar plates/samples.
Have seen something with this idea here and it seems to work okay for them:
1. vertical flow hood, also shows how to get rid of dead air pockets: m.ua-cam.com/video/dqPhy2s_saM/v-deo.html
2. bit different but cool idea with same principle and only a plastic bag: m.ua-cam.com/video/M9FWIu2YLr0/v-deo.html
- I wonder whether it's possible to achieve actual laminar flow with a cheap thin filter if one does the math right and matches filter and fan perfectly. Then also add a proper box behind the filter to disperse the air pressure and all that. Maybe also have something like a big pack of straws in front of the filter to replace the metal fins that direct air forward in proper laminar flow filters. Haven't seen a video about this but I think it's worth trying.
I have thought about doing something like this with a plenum, my thought was to use 2 hepa filters one pre plenum intake, and one for the face. I believe the concept is very much doable, provided the basic concept is somewhat engineered out, fan or fans match, plenum size, filters, seals, etc. Are all designed just right. Good thing about card board boxes is they are free for the most part, so if one design doesnt work you could start over with your main components. Great video, I believe any thing is possible, and certainly a much cheaper design could be fabricated. A laminar flow hood is nothing more than a large filter, with a plenum, and large blower. I have even thought about stacking low cost 99.97% inexpensive hepa filters 16x13 together, say 3 or 4 deep.
Thanks for the video, keep playing around, as I think it is achievable in my opinion. One other suggestion I may try, is to use a cheap, or reclaimed from salvage yard 1 core radiator. Radiators are designed to create laminar flow, it would be easy to cut to any size to fit a 99.75% etc. With a Cheaper filter combination. Only concern will be flushing it out realy good.
Yeah I suppose that makes sense
laminar flow is simple math and traditional DIY laminar flow hoods are about as simple as it can get.. centrifugal fans provide constant pressure where as others like inline fans or box fans create turbulent flow or not enough pressure and could affect your 100ft/m. The filter is what it is you need at least 6in behind your 99.97-99.99 hepa to create the even flow throughout the work space so not really to many corners you can cut. you can make a 1x2 flow hood for less than 300$ and a 2x2 for less than 600$ really depends on what deals you can find and what tools you have(iv seen them built for as low as 400$ for a 2x2). if you want a simple set up for the low budget or someone starting out a SAB(still air box) is cheap maybe 20$ all said and done and if you practice proper sterile technique you should have just as much success if not equal as someone using a laminar flow hood and produce plenty for your family.. then start to use what you have grown using your SAB(still air box) to start a laminar flow hood fund. now if you cant turn a profit or get any success using a SAB(still air box) then its safe to say that this hobby or trade is not for that individual as they don't have the patients to learn sterile technique or have the market to sell the product. a laminar flow hood in my option is only necessary if you plan on expanding your already successful operation and/or are planning to sell on a commercial scale. this shouldn't be someone's first thing they absolutely need starting mycology and shouldn't be the reason why they are not having success. im very interested if you could successfully create laminar flow below 100$ and encourage anyone to figure it out but the problem is people especially beginners will always try to take shortcuts and it could cause more harm then good. if i see a set up with a anemometer showing atleast 80ft/m across the work area i will be convinced but most just show a set up that looks like it should work in theory but is just a simple air filter at heart
Excellent response! Thank you!
I saw th same video,he used an white air purifier to make it.i think his "tote"was 2 big