Well, suffice it to say that all clean room facilities use this exact concept, even lousy transformer winding manufacturers have some sort of positive pressure semi-clean warehouses to keep extremely hygroscopic material (paper) free of moisture, and windings free of flying particulate.

Anyway, I am only wishing that surgical rooms will sometime be benefited from this jerk wondering about this grossly inefficient way to provide a steady stream of fresh clean air.

As a last desperate suggestion, please look at the pressure drop concepts, this will at least give you a clue about the instantly efficiency achieved by you filter (aha!).
Hopefully you will get a better appreciation of the air filtering media exposed area needed per unit of flud flow …

Salu2 !
Yo.

How come you always find the time for this kind of answers… you are at work right now, aren’t you? They will block my site at the company’s proxy if you keep wasting time around, man.

Anyway, I’ll try to address your concerns in this reply, my dear friend. First, I know lousy manufacturers use kind-of clean facilities, even if I have never visited you at work (Prolec).

About the surgical room thing, you should know that most operating rooms indeed use a positive pressure setup, usually with air flowing from top to bottom, at around 30 fpm. Actually is a laminar flow setup (obviously with positive pressure, as air is blown in and exhaust is usually done passively). But I should warn you, nobody knows if it works! (Don’t ask me for details, visit PubMed http://www.ncbi.nlm.nih.gov/entrez/ and do your own search, or visit the ASHRAE web site http://www.ashrae.org/ for some tips).

About the filter topic, in a final experiment I built a cardboard-framed filter panel with three surgical masks; a small box-like filter panel with three times the area of the original filter. The result was improved airflow (a lot!). But it doesn’t look pretty and I have used masking tape to hold it in place. Soooo…

So, I searched for the next obvious design: a folded filter. You know, like those used at cars for filtering incoming air for the gas mix. (An before you wonder, yes, we biomedical people knows a lot about surface areas, as the human body is rich in surfaces and we constantly calculate body, cell, membranes and lot of other surface areas). But of course, how could and engineer (you man!) know what we know?

The calculations done for selecting the right folded-paper filter are… well, that’s topic for another article.

Oh, and congratulations for your new baby, Israel.

Regards,

Mario A. Valdez-Ramirez.

I recently had a chance to look at your filter set up, and let me tell you, snipping the top creases of the folded paper is a perfect way to render the filter useless… air will slip by the openings instead of going thru the paper… well I suppose you know that already, air head !

Got to go, my boss is coming, but just for the record, its 6:20 P.M. and I proudly work in Prolec from 7 to 5, worthless piece of junk (you, not Prolec)

Thanks for the kudos for my boy.

Regards.
P.S. I have been at several surgical rooms already and just 1 of them had an integrated form of ventilation, and that included no recovery or outlet, air was going out thru the door, it was actually keeping the door open… and that includes the UANL HU…

En fin.

Me avente la lectura de todo tu blog, y me parecio muy interesante, lo que mejor “sabor de boca” me dejo es tu forma positiva, alegre y cordial de pensar, especialmente en el caso del rent-a-coder. (de hecho yo he solicitado trabajos ahi!!!)

De hecho me identifico un poco contigo (y perame, perame, perame, no son jaladas gay ni mucho menos , lo que pasa es que tambien me gusta programar en Delphi y tambien me gusta desarrollar pequeñas aplicaciones de codigo libre.

Me da orgullo de que seas paisano (yo soy de Queretaro) y te animo a que sigas por ese camino.

Saludos,

P.D. Y ya que estamos en esto, ahorita estas de Freelance? podrias ayudarme con algo de programacion?

I want ti tell you what I bought the Valley PlasticsTm Computer dust enclosure from Thompson Plastic And Chemical of Toledo Ohio. It is very and durable reinforced with carbon fiber and Kevlar that bullet proof plastic stuff. In your design notes and drawings there is no way to change the air filter as it is bolted into place. A real expensive metal enclosure is the Dust Sheild and they reccomend changing the filters bimonthly in the shop environment I am in so unbolting the filter was not practical and our insurance would not allow us to cut into the casing. So we tried those dirt bags but although they helped a bit they got so dirty in 2 weeks that we wanred to change them but they said they would last for 9 months. We had problems after about 2 months and a hard drive crashed from overheating and because we were using the Dirtbag the manufacturer HP would not replace the hard drive. We build our own computers at the shop so we had to buy the Valley computer enclosure and go with seagate for the new harddrive unit. would need to be changed at least bimonthly as would the dirt bags.

So let me tell you all about them dirt bags they are made of polyester white plastic fiber media and is a sewn bag. I understand that it is a very popular idea but I suspect that many of the people who bough them found out that they have to be changed as frequently as any other filter. So it was a real problem for us. And I liked your blog and this DIY stuff is facinating but basically there are guys trying to make a living selling the cabinets. I looked at everything Iknow what you know so all I am saying is there good people trying to make a living marketing these cabinets on the internet. The web trafic is about 10 people per day globallly for people searching for computer dust as keywords so I don’t see how any of these firms are making more thatn 30,000 a year selling the cabinets or filters per website whoever it is. Therefore, what anither point since this blog takes up page one many of these keywords what i have to day is while it is appreciated all the good work you have done I had to buy the cabinet as an American supporting american entrepreneurialism. As Americans we all want to have our say but everyone had there own idea how do to do something but if we want to truely see the computer dust problem be solved since the manufacturers like IBM are just now getting into this market with a recent patent for laptop dirtbags we have to realize looking at some of the webcounters on these websites that ain’t a whole lot of demand out there for 1 billion people globally that have internet access and a computer that need dust enclosures not bags. Come one of the filters we first bought was polyester and 1 inch thick untill a folded thin filter replaced it and we noticed a big improvement. So I know for a fact having used different filters and from corraoborating your assumptions for the positive air flow that it has to be that way and if you are going to use the polyester white filters they have to changed bimonthly minimum. You can’t just rotate those bags and we had problems enough with HP on our warantee before we found seagate and the Valley Plastics TM Plexiglas Computer Dust Solution. I am not tyring burst your bubble but you can’t have it both ways you either believe in the box you built similar to what I bought or you don’t I do not think that people firms can aford to spend $4800 a year on dirtbags I going to buy the Valley Plastic Tm tower computer cover because I can throw out the filter once a week and buy year supply for $0.50 apiece. End of story period. If I had the money I would of bought the completely bulletproofed and fireproofed for just under $1000. Whatever it would of cost who cares its cool and I have some real protection in any circmstance.