7/23/2023 0 Comments Build laminar flow hood![]() 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. In a horizontal type, the purified air is blown from the back and moves towards the front of the working area. There are two main types of Laminar Flow Hoods : Horizontal Airflow and Vertical Airflow. The alternative.? Construct your own equipment. large corporations, universities, and research institutions can afford this but individual hobbyists like me can not. the one with the very lowest specifications costs more than one thousand US Dollars. However, the cost of the simplest form of the equipment is very prohibitive. 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. One equipment I wanted most but beyond my reach was a Laminar Flow Hood. (round) pipe flow is ~2300 (but you have rectangular channels, could maybe pick the hydraulic diameter), and for a free jet I found a number of 1300, but take that with a grain of salt.Īll in all, you're back to gut feelings.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. The problem is to find the critical Reynolds number that applies to your situation, which is not exactly standard.Ĭritical Re for e.g. The width of the fume hood? (But this is only ~one width long, so hardly counts as a "channel".) Do you pick the width at the end of the small channels in your filter? (but they are triangular/have a non-constant diameter, and flow through the walls to boot). The choice of length scale is important here. With this you get the flow velocity, and you can build a Reynolds number, and if this is higher than a critical number, you'll get turbulent flow. cfm) achieved is the same.Įverything hinges on the pressure loss across the filter (i guess pretty high) and the resulting volume flux of the whole system (depending on the characteristic/power of your fan). My guess/gut feeling is that (due to high pressure loss and flow through a porous medium) the air leaves the filter in a laminar fashion (even if it was turbulent before), so what kind of fan you use shouldn't matter if e.g. I think that such a deep filter will eliminate the need for a screen. Would this be totally wrong? If so, is there a way to build the DIY flow hood to achieve a laminar flow using one of these inline centrifugal fans? It seems to me that so long as the plenum is air tight besides the entry point(fan location) and exit point(HEPA filter), the plenum will achieve a static pressure (based upon the cfm of air driven by the fan and the resistance of the HEPA filter) and flow smoothly out of the HEPA. The argument is that the air pushed by these fans is turbulent and so will exit the HEPA filter in a turbulent fashion. The main question is whether these inline fans will produce laminar flow. The build for a laminar flow hood using these inline fans look, generally, like the two samples at the bottom of this link ( ). Many people are interested in using inline centrifugal fans because they are cheaper than squirrel blowers, more quiet, more energy efficient, and potentially more compact. It is generally accepted that a squirrel blower is effective at creating this laminar flow using the set up in the image posted above. So for years on the mycology, plant tissue culture, and DIY laboratory websites there has been this ongoing debate on how to achieve laminar flow in a home built laminar flow hood.
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