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Re: Anyone tried this for a fume extrator?

PostPosted: Sun Dec 11, 2011 3:06 pm
by steves
If you were to use a whole house heat exchanger you'd still want to have a pretty good filter upstream of it to prevent the smoke from gumming up the core of the exchanger.

Re: Anyone tried this for a fume extrator?

PostPosted: Sun Dec 11, 2011 3:42 pm
by Mark K
I don't think that you need to do an exchange on the laser exhaust. You just need to provide the makeup air from the outside. Take the nice warm room air out of the loop. Either using two pipes (in and out) or a single coaxial pipe. You would need to provide some simple baffles in the laser to direct the airflow. Look at the hardware used in direct vent heaters. They bring in fresh air for combustion through the outer ring and vent the exhaust out the inner pipe. There are a lot of different fittings, combiners, outside terminations, etc. Google Direct Vent.

Re: Anyone tried this for a fume extrator?

PostPosted: Sun Dec 11, 2011 7:27 pm
by steppenshoe
That exactly right. Its how my Reznor explosion proof direct vent shop heater works.

Re: Anyone tried this for a fume extrator?

PostPosted: Mon Dec 12, 2011 5:29 am
by gene
well you could do a heat exchanger that's how HVAC systems do it

Re: Anyone tried this for a fume extrator?

PostPosted: Mon Dec 12, 2011 1:33 pm
by lasersafe1
Wow, it's like Dejavu. Now it's coming back to me. This was all discussed before in an earlier thread with the same outcome. I forgot all about it.

Re: Anyone tried this for a fume extrator?

PostPosted: Mon Dec 12, 2011 6:36 pm
by J45on
Mark K wrote:You just need to provide the makeup air from the outside. Take the nice warm room air out of the loop


A brilliant and simple solution for me and my tiny workshop thanks :D

Re: Anyone tried this for a fume extrator?

PostPosted: Mon Dec 12, 2011 11:38 pm
by dirktheeng
It is possible to use a carbon filter and/or a zeolite material to scrub the air, but you have to know your concentrations, gases, flow rates very well. I have designed and engineered these things for our lab when we couldn't install a regular fume hood. The thing is that you can't really be sure that the thing is being effective without a gas monitor on the outlet. I would NOT do this without that... you could be poisoning yourself and you wouldn't know it. Plus, to be effective, it is VERY VERY expensive and the operating costs are not low either as the material has to be replaced regularly.

A more practical solution is an air to air heat exchanger, but again you really want to be sure that it is air tight to make sure that you aren't getting bypass back into the room. I would just pay the heat bill... you don't run this thing all that much.