Exhaust for downdraft table and some other questions.

[Hi-Vac]

I was just wondering has anyone ever attempted installing a close meshed electromagnetic field under the cutting slats that can be turned on during the cutting process to collect the "plasma dust" while cutting steel. I realize this would not work with stainless or aluminum, but if it helped 90% of the time it might be worth a shot.

[Med-Pac]

Hey slammedonair,

Slow day in the shop, I came across your thread while I was trying to look busy. Here's a couple of pics of our set-up. We have a 4x8 table running a 1000 hypertherm. I regularly cut thicker pcs. up to .50 thk, every once in a while I've had to cut .75. It works, but you have to play with the settings to make it work.

The table is a downdraft witha pull out drawer for the slag. Not sure what the exact specs on the fan are. If you need them I can search around for them. Pretty sure we picked it up at Grainger, and if memory serves I told them I needed a big "barn fan". It moves enough cfm's to suck all the heat out of our 140' x 60' shop though. THe duct work is 24" x 24", and we mounted the fan inside the duct. Easier to work on if we ever have a problem....especially in the winter.

hope this helps ya
Mike

[Med-Pac]

Forgot to finish typing!!

The fan is mounted in the darker steel box you see in pic 2. My advice on the fan choice is to go with the biggest possibility that you have power for. If it doesn't perform the way you need.......get 3phase or open the door!

Mike

[WSS]

Water table-

No electric bill
No 3ph
No ducting
No heat loss in building
No warping

No, No, No...........

Just a thought!

WSS

[slammedxonair]

Yea I wish I would have known all of this before I got my downdraft table... off Dynatorche's web site "Uses a low volume customer supplied vacuum source (exhaust fan)."
I wouldn't call a 3 phase 3500 cfm blower a low volume exhaust fan....

[slammedxonair]

what is static pressure and why does it need to be 2" ?

[LeonD]

All fans are rated by CFM and Static pressure. Both must be specified as the fan has a performance curve. As static pressure (back pressure or suction pressure) is increased, air flow volume decreases. Maximum pressure (or suction) is acheved at zero CFM (blocked inlet or discharge). On the other end of the scale, maxiumum flow CFM is acheved at zero static pressure. The air table system has a small amount of static pressure loss that must be overcome. This is the 2" water gauge pressure. Low pressures are rated at inches of water column. That is the pressure required to lift water in a tube by X inches.