Exhaust blower selection

[billvoughn]

Hi guys,
I posted the following on the laser section but have some additional questions on the static pressure and hope you guys can help:

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I have a question regarding a fume/particle collection system for my laser working with cutting some mild steels, stainless steel and also with ceramics. The working space is about 29Dx24Wx30H in (about 14.5 cubic feet).

I've been trying to find some exhaust blower to work for those aforementioned conditions. Given the fact that there will be some carcinogenic agents when working with mild and stainless steels, what kind of blowers should be used? The min cfm I am looking for is 170 cfm (air exchanges every 5s). I wonder whether it is enough. I should not worry to much about the fume system when working with ceramics, right? The main concern then will be particles?
*****

Some blowers on grainger.com give different cfm on different SP. The SP inside a laboratory is 0 in SP? If it says CFM @0 in SP is 270; that means the cfm right outside the blower is 270? What would be the SP along the duct hose connecting from the blower to the fume hood? What effects does the hose length have on the air flow?

Thanks for your help,
-B.

 

[willard3]

The ACGIH has many details of particle-removal exhaust systems.

http://www.acgih.org/home.htm

You should find someone who understands ventilation/exhaust systems.

 

[imok2]

Bill, try this web site

http://sentryairsystems.blogspot.com/2010/06/laser-fume-extraction.html

 

[cdxx139]

bill,

work backwards. What velocity do you need thru the hood to exhaust the smoke or particles you are using. This should be found in the Industrial Ventilation handbook.

As for the static pressure, it wouldnt be zero, if I assume you will duct from the hood, to the fan to the outdoors. You will need a static calculation done. The hood can easily be 0.5 in wc static.

You seem to require assistance with some fundamentals, that I may not be able to assist with. You really should hire an engineer.

Good luck

knowledge is power