My interest in Mycology and Tissue culture started long back which led me to collect few laboratory equipment like Petri dishes, test tubes, weighing equipment, measuring glasses and also chemicals like Hydrogen Peroxide, Agar-agar and Potassium Permanganate. One equipment I wanted most but beyond my reach was a Laminar Flow Hood.

A Laminar Flow Hood provides a small sterile work area, where you can carry out all your culture works without the risk of contamination, simply by flowing completely purified air at a specified rate. However, the cost of the simplest form of the equipment is very prohibitive... the one with the very lowest specifications costs more than one thousand US Dollars... large corporations, universities, and research institutions can afford this but individual  hobbyists like me can not.

The alternative...? Construct your own equipment...

There are two main types of Laminar Flow Hoods : Horizontal Airflow and Vertical Airflow. In a horizontal type, the purified air is blown from the back and moves towards the front of the working area. In a vertical type, the air is blown from the top over the working area and moves out through the base

I have carried out extensive study and came out with a design for constructing a Horizontal type Laminar Flow Hood, making use of a vacuum cleaner for the blower and press board / Plexiglas for the hood body thus reducing the cost considerably.

This Instructable will provide you step-by-step instructions on how to build your own portable Laminar Flow Hood without any compromise on standard specifications.

Step 1: Vacuum Cleaner As Blower for a Flow Hood...?

Are Vacuum Cleaners Suitable for Laminar Flow Hoods as blowers...?

I have used Euroclean Star model vacuum cleaner to be used as blower in the flow hood. Let us check out the facts for its suitability for quality and effectiveness for being used in a flow hood.


The model I used consists of unique five stage filtration process and the air coming out after filtration is pure and fresh...

The first stage involves the incoming air to pass through a special particle, anti-microbial, biocide treated paper filter which has been treated for protection against bacteria, fungus and yeast. This paper bag is replaceable and can be used for up to five times. However, for better results, we can use fresh bag whenever we use the laminar flow hood. This air then passes through a cloth bag, which filters out any particle which escapes through the paper bag. This bag can be removed, cleaned and then placed again in position. The next three stages involve the air to pass through specially designed built-in electric filters with carbon which blows out completely pure fresh air.

I have removed the outer-most filter and provided a cheaper version of High Efficiency Particulate Air (HEPA) filter between the air chamber and the work area. I have also added a pre-filter to remove any heavier particles before the air is sucked into the vacuum cleaner.

Work area provided by the blower

Laminar flow hoods are designed to provide an air-flow of about 0.5 meters per second in the working area. The blower efficiency of the model I have used is 20 liters per second, that is 0.020 cubic meters per second including all filters. I have removed the outer most filter from the outlet for connecting the outlet pipe, and used the HEPA filter instead.

With 0.020 cubic meter of air per second, let us see how much work area it can cover

Air flow provided by the blower = width of HEPA filter x height of HEPA filter x air speed required

Work area (width x height) = air flow / air speed
                                            = 0.020 / 0.50
                                            = 0.04 square meter

Now, if we provide HEPA filter area of 0.27 meter width x 0.15 meter height, the available work area will be 0.04 square meters, which is sufficient for the effective functioning of the flow hood. I have provided the filter dimensions of 0.29 meters width by 0.15 meters height, considering the size of HEPA filter I could lay my hands on.

Advantages of using a Vacuum Cleaner as blower

There are some advantages in using vacuum cleaners, which may not be provided in a Laminar Flow Hood

  • The air input level can be adjusted using a slider provided with the vacuum cleaner as per our requirement. Not all blowers in the laminar flow hoods are provided with adjustable air flow.
  • There is also an option to heat the input air, which will be helpful in sterilizing the air chamber and back side of the HEPA filter which can not be normally accessed.
  • What is more, you can vacuum clean the air-tight Air chamber by reversing the airflow by the vacuum cleaner unit.
  • The vacuum cleaner unit can be separated from the Laminar Flow Hood, which is not at all possible with a normal unit.
The only disadvantage of using a vacuum cleaner is its limited airflow which limits the size of the sterile work area.

I think a suitable vacuum cleaner will serve the purpose of blower in a small Laminar Flow Hood for hobbyists, thus reducing the cost as well as the weight of the flow hood considerably.
<p>Sorry but this is a total waste of time and money. For laminar flow you need the proper hepa filter matched with the proper blower to achieve 100 cfm. Anything else wont proved true lamiar flow. Also pressurized glove boxes defeat the purpose and increase contaminants. The way a glove box works is to create dead air with no turbulence so the continents drop to the bottom after a spray with water.</p>
<p>I have to concur - you cannot achieve laminar flow with a filter like that. Let's assume you have a filter 12x24x6&quot; (which is what medical grade hepas are, 99.89+ at .03 microns and .8-1.0 inches of water) You need a matched blower - at 12x24 with a static pressure of .8, and a prefilter at .2, you need something to pressurized the plenum behind the filter, and to get the needed pressure you need to have a blower pushing (for this size calculated) 200CFM - but here is the rub - every manufacturer has data sheets. So although a motor can push X CFM, they may not be able to do it at 1.0 inches of water (which is the key). An example is the Dayton blower we use can push 273 cfm at .5, 245 cfm at 1.0, and only 135 cfm at 5.0 // Also, you don't want the incoming air directed at the rear of the filter - to achieve laminar flow, you not only need a thicker filter, you need to pressurize the area directly behind it. Most flow hood motors blow at a 45 degree to the filter elements for this reason. It's a function of higher pressures finding their way through the filter with resistance, that provides laminar flow, not the cubic feet of air the pump can provide. SO that all being said ... if your design works for you, congratulations. It was a cool read, and you should be happy with your results, but in the end, I agree with Tom.</p>
I don't think you have gone through all the steps of this instructable fully.
<p>It's a great idea and I want to make one. The one thing I'm not clear on is the suck/blow problem. I'm probably missing something obvious, but I don't see where my vacuum cleaner blows the air out. </p>
<p>Please look at the arrangement of air inlet and HEPA filter assembly. The air from the vacuum cleaner is blown into the backside chamber of the Laminar Flow hood. All other sides of the backside chamber is air-tight other than the HEPA filter area, through which the purified air passes through, providing a clean area to carry out your work.</p>
<p>Nice job! I would love the instructions as well! prpkitplasma@gmail.com</p>
You can access the files in the following Dropbox link<br><br>https://www.dropbox.com/sh/h6qxco91uundyco/AAC-pSBTimMj6_3K2T6_nZcQa?dl=0
<p>Could you please send the instructions to cvwsaw@msn.com. I can't get the drop box to work. Thanks!</p>
<p>Please see the attached files sent to your mail</p>
<p>Hey there!<br>Thank you soooo much for the write up - This is pretty neat :) <br>I&acute;ve<br> built something similar (converted an old Glove Box - bad idea <br>actually, because the lateral Airflow is prone to turbulence and spreads<br> contamination easier then a flow directed at the user... But I <br>digress...)<br>I&acute;m having difficulty understanding the calculation of <br>Blower Speed to Work area though. Could you please give another example <br>calculation for something bigger?<br>I&acute;m Trying to calculate the Work Area for a Setup thats just a tiny bit bigger ;)<br>Here&acute;s what i got so far:<br>My Blower will have appx. 700m&sup3;/h of Airflow.<br>I&acute;d like to have a Filter size of 52x34 cm.<br>So<br> according to your Formula i have 0,52(width)x0,33(height) = 0.1944 <br>(m&sup3;/sec) /0,5 (Airspeed required for the whole concept to work).<br>That would result in 0,093465 = 0,4 - which is obviously false :/<br>I just cant wrap my Head around this :D<br> Where am i going &quot;off Track&quot; here?<br>Anyways, thanks a lot again, really good stuff!</p>
I have uploaded two files to dropbox which you can access from the following link. I hope this will give you some guidelines on constructing a portable laminar flow hood including calculating the air flow and filter area<br><br>https://www.dropbox.com/sh/h6qxco91uundyco/AAC-pSBTimMj6_3K2T6_nZcQa?dl=0
<p>I think there might be an easier way to do this.... share your thoughts. Instead of all the expensive filters run the air through a water chamber just like using a water pipe. as the air bubbles through it will drop the impurities into the water i. e. wet dirt and dust can't fly. then on the other side put a small fan to push the water washed air on through. water is much cheaper than &quot;hepa&quot; filters. not to mention most of the so called hepas present day aren't true hepas they just stole the name from the original. You might have to make more than one water chamber to eliminate impurities so depending on space maybe your way would work. another way you could do it is to run a small mist sprinkler inside a container and push the air slowly through it just like when it rains outside the water traps impurities and the air smells so clean after. These are just guesses, I could be completely wrong, but I am going to try it on mine.</p>
Please try it and share your results
<p>I definitely will</p>
That is incredible
thank you...
<p>nice design, now that its been used for a few years would you do anything different?My only concern is gluing the filter...since they periodically need replacing , what about sandwiching it between 2 plexiglass cutouts or soe other way so that replacing them might be easier. thx steve..btw I do both mycology and plant tc as well</p>
<p>thank you... The design ideas are limitless. If you can sandwich the filter between 2 plexiglass cutouts without any leakage which makes it easy to replace that is well and good. Nice to know that you do mycology and plant tc</p>
<p>grow cp's and edible and others on straw, so email if interested in exchanging cultures</p>
<p>WOW this is great! It's a great development. Thanks for sharing! Could you please send me all info by email? I can't download the PDF. Thanks!!</p>
Please give me your mail ID and I will send the details.<br><br>Alternately, I will give you the code for 3 months Pro membership which will allow you download as many articles you like
<p>Hi Antoniraj, </p><p>Thanks for your response! Please send me the files/details to my email:</p><p>watto1999@hotmail.com</p><p>(I've sent a previous message with a mistaken email, so I've deleted it!)</p><p>Thank you!!</p>
<p>No problem, please go through files sent to your mail</p>
<p>Thank you so much Antoni!!<br>I really appreciate your help on this regard! Many blessings to you!</p>
Very helpful. Sir could you please mail me those valuable Information to jithintr@gmail.com
Please see attached files sent to your mail
A most genius design and idea!! Could you email me the documents as well please? Thank you Antoniraj!
please give me your mail id...
<p>Oh my gosh this is AMAZING!</p><p>Please I would be very grateful if you could send me all the documents too!</p><p>thank you so much!</p><p>399nik@gmail.com</p><p>Thanks thanks thanks</p>
<p>Please go through the attached files sent to your mail</p>
Thank you very much Antoniraj!!!<br>Really appreciated!
<p>This is wonderful and I thank you for your time and effort. If would be so kind would you please send the attached files to sunraeljah@gmail.com also. I am much obliged and have a awesome day. Thank you.</p>
<p>Please go through the attached files sent to your mail</p>
<p>Wonderful<br>Instructable! I have been trying to figure out a way to use a fairly<br>strong HEPA blower/fan<br>(?) I got from a friend of mine when he was moving and it has never been used<br>but it doesn't fit the &quot;filter&quot; pictures I've been seeing<br>its round like a canister and has the HEPA filter wrapped around it with<br>a fan blowing air OUT at one end thus all air that is being pulled in <em>through </em>the<br>filter. I was wondering if you think it could be used somehow for a portable<br>Flow Hood? Any ideas on that matter? I tried to make a 'glove box' with a clear<br>plastic tub turned upside down and the HEPA filter blowing in to sterilize the<br>interior air. There were pressure problems right away with so much air<br>blowing into a &lsquo;sterile air&rsquo; container with nothing but the strip of door<br>insulation I used to try to make a snug fit between the bottom of the box<br>(which was the storage tub's original lid) and the storage tub itself<br>failed miserably. Not to mention the 4&rdquo; of PVC pipe I used to attach my gloves<br>to wouldn't stay sealed in the holes I had cut into the sides of the clear tub while<br>trying to use the gloves working inside of the box. </p><p>I&rsquo;ve drawn a rough sketch (on Word no less!) of the HEPA<br>unit I am trying to describe but I&rsquo;m not sure how to send it to you.</p><p>You can email me at joem104 at gmail.com if you like.</p><p>By the way I LOVE your choice for favorite quotes! Robert A.<br>Heinlein is one of my favorite authors I love the way he thinks or &ldquo;Grorks&rdquo;<br>things. I believe that was the phrase he used in his book &ldquo;A Stranger in a<br>Strange Land&rdquo;.</p><p>Sincerely,</p><p>Micki A.</p>
You can cut and remove the HEPA filter from the round canister and mount it in a rectangular frame.. It is very easy. I have recovered a filter like that from a round canister. The fan provided with the canister may not be sufficient for blowing out the air required for the laminar flow hood. You can use a separate blower or use a suitable vacuum cleaner as I did here.<br>Please also refer the files sent to your mail for further information
<p>Hi, would you be willing to send me details on how to construct this at clio.byrne-gudding@yale.edu? Thank you!</p>
<p>Please see attached files sent to your mail</p>
<p>Hi, can you please send me details on how to make this!! pngulu@gmail.com. Thank you.</p>
<p>Please go through the attached files sent to your mail</p>
<p>Ingenious! would you please send me the details at dont.forget.the.trees@gmail.com Thanks for sharing your work!</p>
<p>Please go through the attached files sent to your mail</p>
<p>Please email instructions to pinealplatypus@gmail.com This is such a wonderful idea! Kudos to you! :)</p>
<p>Please go through the attached files sent to your mail</p>
Hi, can you please send me details on how to make this!! Thebloomingjungle@gmail.com thanks nick
Please see attached files sent to your mail
Hi would you be able 2 send me details on how to make 1 please to richardsteventon@hotmail.co.uk it's a great idea
<p>Please see that attached files sent to your mail for more information</p>
Thanks great help
I would like to have the detailed instructions. This is great! boonkiat88(a)live.com
<p>Please see that attached files sent to your mail for more information</p>

About This Instructable




Bio: I like to make things more simple with easily available resources. My favorite quote: A human being should be able to change a diaper, plan ... More »
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