![]() ![]() Clean benches can be used for certain clean activities, such as the dust-free assembly of sterile equipment or electronic devices, and they should never be used when handling cell culture materials or drug formulations, or when manipulating potentially infectious materials. These devices only provide product protection. ![]() Horizontal laminar flow or vertical laminar flow “clean benches” are not biosafety cabinets these pieces of equipment discharge HEPA-filtered air from the back of the cabinet across the work surface toward the user, and they may expose the user to potentially hazardous materials. Vertical flow hoods, on the other hand, provide significant protection to the user and the cell culture. ![]() The flow can be horizontal, blowing parallel to the work surface, or it can be vertical, blowing from the top of the cabinet onto the work surface.ĭepending on its design, a horizontal flow hood provides protection to the culture (if the air flowing towards the user) or to the user (if the air is drawn in through the front of the cabinet by negative air pressure inside). The Sanyo Denki 9GV1512H501 should be able to handle this though we may need to bump it to 13V or so.Laminar flow hoods protect the working environment from dust and other airborn contaminants by maintaining a constant, unidirectional flow of HEPA-filtered air over the work area. Instructions on how to figure out the maths of achieving laminar flow through a HEPA filter can be found in this helpful PDF. We need to find a blower that will blow the right amount of air through the filters to create laminar flow. That means we need to opt for the UMPW78 18x24 ( spec sheet). So far I have had no luck in getting the pressure drop information about the filters from Fellowes, an alternative is to use this costlier filter (UMPW78132418) from a company that will be able to provide detailed informationĪfter finally discovering the specs of the Fellowes filters, they're not appropriate. The Filters Can Remove Between 99.99 and 99. Labs doing any kind of precision experimental work should really have laminar flow hoods in their toolkits. So far these filters on Amazon appear to be our best option - we can put two next to each other to achieve a 64x42cm work surface. In any kind of sensitive experiment where the slightest contaminant or disturbance can throw everything off, the importance of this cannot be overstated. The entire 'ceiling' of the flow hood must consist of filters, so the dimensions of worksurface of the hood are constrained by what size filters we can find for a reasonable price. They are often used in air conditioners and air purifiers. HEPA rated filters will remove any bacteria and other contaminants from a flow of air. However the ethanol may work its way under the tape and cause the adhesive to loosen. A much cheaper alternative that may work is simply sticking PTFE tape along the edges. So far the only ethanol resistant sealant I have found is PRC Rapid Seal which is rather expensive. As with the side panels, the sealant must be resistant to 70% ethanol, so ordinary bathroom sealant is out. The inside edges of the flow hood need to be sealed and air tight. Unfortunately 70% ethanol kills perspex over time so we should use glass for the sides and a sheet of polypropylene for the work surface. We need to construct a frame: perhaps weld together some steel box section or chop up and repurpose an old shelving unit or construct it out of makerbeam, openbeam or easy fix.īecause we will be using 70% ethanol for sterilisation, the materials used for the sides and work surface must be resistant to this. SketchUp file of proposed design Construction and Materials Frame Here is a basic diagram of what it should look like. We should aim to build a vertical flow hood as that not only protects cultures from contamination but protects the user from the cultures being worked on. Place the filter in the hole in the container lid. Make a filter by soaking a piece of cotton or sponge in isopropyl alcohol and then wringing it out. Switch on your hood’s fan, and move the container and lid inside for drying. A Laminar Flow Hood would enable us to greatly improve the aseptic technique protocol in the hackspace. Wash the container and lid with soap and water, and then sterilize by immersing them in simmering water for 3 minutes. ![]()
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