Hi,
So far I have learned that coating plates is easy- but coating Good quality plates is hmmm.... tricky.
I'm looking for some idea for the DIY laminar flow station to get rid of dust particles (one big obstacle for quality I see, second would be the presence of nasty air bubbles).
Could You- the society clarify the topic of "laminar flow station" for coating a little- some practical advices?
How the "drinking straws" are used- google is not friendly here somewhat for me?
There is a one nice scheme of station on Johns holograms3d.com site- what HEPA filters and flows are sufficient for getting rid of "typical dust"?
Thanks in advance!
Marcin
laminar flow bench-Howto?
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Joe Farina
- Posts: 805
- Joined: Wed Jan 07, 2015 2:10 pm
laminar flow bench-Howto?
A home-made laminar flow station will mostly depend on the kinds of materials you have access to. But in simple terms, there are four parts to consider 1) the box which contains the elements of the station (I used white melamine-coated particle board), 2) the fan or fans which are located at the very back of the unit, which push air out towards the front (I used a window-type unit which has 2 fans mounted in a single assembly) 3) next comes the hepa filter. It is best to have the actual hepa filter before the box is constructed, so that the dimensions of the box match the size of the hepa filter. 4)finally, some means to make the air coming off the hepa filter come "straight" out (I used a large quantity of cocktail-type drinking straws which are smaller than the usual variety. I used these because they were locally available from a restaurant-supply store.) Then comes the empty space at the front of the box where the coating is made.
Conceivably, a wide range of materials could be used to make some kind of honeycomb or screen to make the air come straight out. The thing which makes a laminar flow station useful is that there are no eddies, swirls of air, etc. that cause dirty air to re-enter the box. The way to test this is to put a candle flame in front of the unit while it's operating. Slowly move the candle flame over the entire area of the opening in front. If the candle flickers or dances around at all, that means that there are eddies or some kind irregularity in the flow, and the system would have to be re-designed. But if the candle flame "bends" and stays bent in that position wherever you position it, that means the design is a success. It's a rather strange sight to see a flame bend like that, almost like it's locked into position.
It's also essential to keep the box covered (the front portion sealed off by some means) whenever the station is not being used, otherwise dusty air will get in and cause problems later.
Conceivably, a wide range of materials could be used to make some kind of honeycomb or screen to make the air come straight out. The thing which makes a laminar flow station useful is that there are no eddies, swirls of air, etc. that cause dirty air to re-enter the box. The way to test this is to put a candle flame in front of the unit while it's operating. Slowly move the candle flame over the entire area of the opening in front. If the candle flickers or dances around at all, that means that there are eddies or some kind irregularity in the flow, and the system would have to be re-designed. But if the candle flame "bends" and stays bent in that position wherever you position it, that means the design is a success. It's a rather strange sight to see a flame bend like that, almost like it's locked into position.
It's also essential to keep the box covered (the front portion sealed off by some means) whenever the station is not being used, otherwise dusty air will get in and cause problems later.
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holorefugee
laminar flow bench-Howto?
That is a great summery Joe. I would add that there is lots of variation, the fans can be mounted below a station and blow into the box. I like very large HEPA filters to keep the air flow high. The one I have is used mostly for biological sterility (repackaging dry yeast) and has been in daily use for 10 years. It was purchased used 10 years ago.
It has built in lighting and I would recommend having internal lighting unless you are coating outside the box and only using the box to dry the plates. Making al of the surfaces easily cleanable will be of big help if you have a contamination issue at any point. I have a Melamine work surface and the sides and top are Lexan. The corners are very easy to clean. I have had to resterlize the bench often and it is quite easy. Insuring sterility is another matter...
It has built in lighting and I would recommend having internal lighting unless you are coating outside the box and only using the box to dry the plates. Making al of the surfaces easily cleanable will be of big help if you have a contamination issue at any point. I have a Melamine work surface and the sides and top are Lexan. The corners are very easy to clean. I have had to resterlize the bench often and it is quite easy. Insuring sterility is another matter...
laminar flow bench-Howto?
Thanks guys!
This is great collection of tips- will be useful for me and others!
Would it be possible to also add some few pictures of your working devices- to get still better perception on how some working devices looks like (the straws part, overall size). One picture worth million words
Greetings!
Marcin
This is great collection of tips- will be useful for me and others!
Would it be possible to also add some few pictures of your working devices- to get still better perception on how some working devices looks like (the straws part, overall size). One picture worth million words
Greetings!
Marcin