How to Build a DIY Laminar Flow Hood

welcome back to all the gear today on all the gear I build this this is a DIY laminar flow hood that you can use for tissue culture mycology or any other activity that requires a sterile working environment it's a design that uses cheap HEPA filters on the intake to HEPA filter air and a cheaper nerve re-washable filter on the laminar Flow side to make this build affordable for most people okay so I first want to start by defining some terms laminar flow in fluid dynamics is characterized by fluid particles following smooth paths in layers with each layer moving smoothly past the adjacent layer with little or no mixing that means that there are no cross currents Eddies or swirls within the flow of particles you've probably experienced laminar flow in scenarios like the water exiting the end of a hose or a stream of water passing over a waterfall when a stream of particles is traveling within a closed Channel such as a pipe or in our case the flow Hood there are two types of motion that can occur depending on the velocity and the viscosity of the fluid lamina flow and turbulent flow turbulent flow involves mixing of the fluid and turbulence within the particles and this is what we're trying to avoid with our laminar flow Hood now the second term that I want to Define is laminar flow hood or cabinet and this is laminar flow cabinet it provides a laminar flow a particle flow or an airflow that comes towards the user from the back of the cabinet at a rate of about 0.45 meters per second this is essentially a wall of air that moves towards the user all the air particles are moving in a laminar fashion where the layers of air do not intermingle and there are no Eddies and this is useful because it protects anything within the cabinet from the user and the exterior of the cabinet because of the positive pressure coming towards the user that the airflow provides now there are many uses for laminar flow hoods including mycology and the growing of mushrooms assembling medical equipment electronics and lenses anything you are trying to Omit dust and small particulate from food processing Pharmaceuticals and cell tissue culture which is the reason that I've put this Hood together today all of these tasks require a sterile or dust free environment within which the user can work they are essentially a low-cost alternative to a clean room that allows a user to quickly and easily interact with a sterile environment now if you're looking for my plant cell tissue culture videos they're actually on my other YouTube channel Linked In the description of this video okay so now that we know what laminar flow is and what a laminar flow hood is used for we can get to building one so in my designing of this laminar flow Hood I wanted to make it cheap and accessible to everyone so this laminar flow Hood comes in at under 250 US dollars with all of the major components the plywood the large fan the two HEPA filters and the Merv filter used for the laminar flow under 250 us 244 to be exact and 361 Australian things may get a little bit confusing because I start off using a completely different fan and I realized my mistake halfway through the build hang in there don't just go and purchase that first stand because there are some mistakes that I make that you can learn valuable lessons from without spending the money that I did for the box I'll be using 1200 by 1200 plywood it's really simple all you need to do is cut up the ply into 600 by 600 pieces so it is four equal quarters one of the quarters you're going to take an extra 19 mil off in my case because it's 19 mil ply whatever the size of the ply that you're using take that much off the edge of one of your pieces so the beauty of this design is you can get away with using a 1200 by 1200 piece of ply and then you can fill it in around your filter with other smaller pieces of Timber if you don't have a circular saw or find it hard to use power tools just get your hardware store to cut up the pieces into the plan that I will have written in the description below that will reduce most of the handy work that you'll need to do to create this Hood okay so now we've got all our pieces I'm just going to clean them up with a bit of sandpaper and we can head inside okay so we're now going to Sam ball our top and sides like so I'm actually going to pre-drill just to stop any splitting we should just be able to slide our back piece in and it should line up perfectly foreign box compartment for the hood I've designed it to sit onto a banished top which is exactly this deep which is 600 deep is actually this one here which is identical to the one that I'm working on I won't have the full 600 because I'm going to add in this bottom piece here the back this is also kind of where you can customize This Hood the way you'd like it that back plate that face will be able to fit in a variety of different filters that you can purchase online internally I'm going to paint and silicon all of the edges and I'm going to screw that back plate in as well these next two parts are most definitely optional I'm just going to run a router around some of the edges that I want to be chamfered and I'm also going to hit it with the blowtorch seal the outside and give it the same look as the rest of the set [Music] this is what it looks like after the burning and I haven't done the inside because I want to paint that white so that I'm able to clean it um a lot easier so I'm going to paint the internals of the cabinet with an exterior paint this is the closest I could get to a laboratory paint everywhere that isn't burnt I'm going to paint so it's been about 24 hours I'm now going to add in the entry for the airflow into the back of the unit so now is probably a good time to explain why I'm adding in a HEPA filter on the intake rather than as the rear filter I actually did buy a HEPA filter to suit this the auto was refunded because they weren't available and I did a bit of research and found out you don't need a HEPA filter to create laminar flow we only need the type of filter that you would fit into what the Americans would call a HVAC system so a Merv particulate filter a washable nerve particulate filter will do just fine for laminar flow that means that this system will rely on this HEPA filter to filter out small particulates like viruses bacteria and bacterial spores and this HEPA filter only costs about 42 Australian dollars this is just a wet dry vacuum cleaner our HEPA filter to add this to our fan I jumped on a CAD program and I designed this this fits over the top of our intake and accepts the HEPA filter now the HEPA filter has a rubberized this isn't plastic this is rubber it has a rubberized ring around the outside it will fit directly over the top of our inline centrifugal fan and it just pushes on how good like so I've also designed this is purely aesthetic it's just so that I can adapt ducting to the top of the unit and then use a steel hose clamp to attach it to both this and the centrifugal fan and here I'm just drilling out the windows in the sides [Music] so now we're going to do the large hole on top if you don't have a really large hole saw just trace the hole out and use a jigsaw [Music] now that we've drilled our holes and our paint is dry we can add on our fan and our duct and our windows so the duct is pretty easy I'm just going to Silicon around it so that we make it airtight and then we can screw it into place the vent over the top I can tighten that nut now I can sort of lay out where I'm going to put the fan I actually think just having it like that will be fine I'm gonna have it dead center because it works fine okay so it's now time to add in the windows which is an optional thing so I'm going to pre-drill out all the holes and countersink them as well because you don't want to force the screw heads into these because it will split the perspex and once you're happy with that we can then screw it into place okay so annoyingly the filters taking longer than I expected now the filter I'm using for the back of this compartment it was meant to be two HEPA filters that were cheap HEPA filters from Kmart that fitted one of their anko HEPA filter units however Kmart send me an email saying that they run out of stock we're going for an alternative route we're not going to use a HEPA filter the filtration on the top is a HEPA filter so the filter at the back is only required for the laminar float we just need the filter to essentially strain the airflow through a mesh or some kind of filtration material I'm going to make the back of this filter I'm going to build the frame and sandwich between a screen printing fabric it is permeable it'll allow air to pass through it aquarium filter material I'm actually going to skim through this part I abandoned this approach but it wasn't a total waste of time because it allowed me to discover that the fan that I was using wasn't powerful enough didn't have enough output for the task I wanted to use it for and there it is that is the laminar flow filter finished and we can slide that into place all right I'm gonna do a couple tests and we can see how it performs sometimes if I block this nope all right let's try without the aquarium film at all okay we're down to a single sheet of screen printing material now you can see that there is flow coming out from the fan but the problem is it's sucking it in at the top because adding we need to stop that okay so that didn't work back to the drawing board it seems like the fan only has the ability to push air enough for like probably a sliver of the filter which makes sense now that I think about it I thought I'd actually have to turn the fan down oh this is okay so the fan was not powerful enough now I thought about adding in more fans but I just went for the buy a larger fan option now I've seen a lot of people using the AC Infinity fans but this was much cheaper off Amazon this was the dark turbo eight inch 200 millimeter inline fan I'll link it in the description below it was 209 from Amazon and it moves 710 CFM pause now for the performance information of the fan this is going to be about four times more powerful than the fan that I was using so hopefully it will be large enough I will however need to be cutting a larger hole into the top I've also had my filter arrive this is just a HVAC filter it's a washable filter so I'm going to open this up we're going to see how much air it pushes and a major reason for the purchase a variable speed controller that's halfway that's massive yeah don't put anything in front of it wow I think this is gonna work so this is going to sit like upside down like this on the unit I'll have to redesign this part maybe let's see we might actually just get lucky here to be able to just sit that in if I can just sit that on top that might seal itself definitely reduce the flow so I'm now going to remove my old fan I'm not even going to bother with ducting I want it to drop directly into the top of my hood I'm going to cut a hole directly into the top and drop in the fan hopefully into this should just fit nice and snug so now I'm going to get to putting in this Merv filter it's a HVAC filter this is the dimensions 20 inch by 24 inch by one inch so it's 51 centimeters by 61 centimeters by 2.5 centimeters there we go it is just a filter material we have this aluminum protection and it has just got PVC edges which will allow me to fit it into place the airflow is shown here so the flow actually comes out with the aluminum side on the front which is good because I want that to protect the screen if something for it to fall onto it it is perfectly sized it looks like which is quite exciting I mean I did plan that but as you've seen plans never go quite as planned if we have a look here hahaha that's incredible that actually fits perfectly I'm gonna need to make a piece that fits in the top like that so now what I'm going to do is silicon up and paint all the internals but it's nice and sealed up and then I'll install the filter by screwing it into place so I just designed a new collar for the new fan so I'm going to be 3D printing that now I've installed the fan I slid the sleeve over the top of the fan siliconed it up and slid the fan into place now I'm going to put it into the location where it's going to live and we can retest the airflow okay so since that last scene I've actually used the laminar flow Hood to transfer a bunch of explants into sterile tissue culture media for the experiments that I'm undertaking with cloning plants at the moment and you can see the laminar float wood in action now initially with a single filter on top the fan was struggling to put out enough air because of the restriction on the intake of the fan so what I ended up doing was I ended up just adding in another filter now these filters are just placed literally on top of our fan unit and because they are a pass-through filter you can just remove the top of one of the filters and stack them as high as you like and the rubber on the filters seals with the pressure that the fan is sucking them together with so there's no need for a 3D print at all because just coincidentally the fan is the perfect size to accept the rubber on the outside of these filters and when you turn the fan on the suction actually pulls the filters into place and they seal now it will obviously be better if you tape this up and I will be taping this up but as you can see it works perfectly fine without any 3D print or any skilled adjustment at all and if you're not happy with the flow because it is causing too much suction you just add another filter and it adds surface area I can feel the air being taken in there and you can see the air being sucked into our filters and down on the actual laminar flow we've got really nice flow across pretty much the entire Hood so we've got a really steady flow as you can see and I even went as far as purchasing this this is an anemometer and it is to calculate wind speed so right at the hood we are at one meter per second and then one meter per second in the middle as well one meter per second at the sides it's about the same across the whole base which is encouraging and this is on Full the ideal speed is between 0.36 and 0.56 so I'll just turn that down like a fraction now the problem is that this doesn't go below one meter per second it's it's just not accurate enough and there it is that is how you build a DIY lamina flow Hood I'm actually stoked with how this turned out I'm really happy that I was able to get my plant tissue cultures out and propagating and so far so good I haven't had any visible contamination okay so I hope you enjoyed my build of this DIY laminar flow hood and my journey from no idea to some idea check out the videos Linked In the End screen for similar topics that you might find interesting don't forget to subscribe to this Channel and my other channel who chose where I actually undertake all of the plant cell tissue culture that's it today for all the gear and I hope I left you with more of an idea

Channel: All the Gear. No Idea...

Views: 60,197

Keywords: Laminar, Flow, Hood, Explained, Laminal, Cabinet, DIY, HOW, to, Build, Cheap, Easy, Mycology, Tissue culture, Hepa, Merv, Home, Filter, Fan

Id: cfXeKBorpAY

Length: 20min 34sec (1234 seconds)

Published: Fri Jun 23 2023