[herrmc]

Hello All...

I purchased my table without any way to manage the dust and smoke... I regret this now.

My table would be very easy to enclose the bottom area and duct it outside... but a couple of challenges I don't know how to deal with are:

1.) Even distribution of the downflow across the entire table
- I don't want to have to cover unused areas.

2.) Collection of the debris so that it is not blown out into the environment (preferably with some type of "trap" instead of a filter).

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I look forward to any comments suggestions!!!

[plasmapunk]

I have a 5x10 table and use a 2500 CFM cyclone filter and it does great. I do cover the open areas. As for distribution I just have a 10" pipe in one end sticks in about 4" and I have no problems.

The cyclone does a great job removing the dust.

[AER Rob]

I am a design Engineer and we manufacture industrial downdraft tables. The most effective method to get even velocity at the table top of your downdraft table is to provide a fairly high airflow which in turn will give you a high suction velocity across the table. In a few spots it maybe high and in other spots low. The location of your pick-up in the plenum box under the table is critical, I would locate the collar in the middle on the back of your table, this will give you the best chance of more of an even downdraft velocity.

[herrmc]

So here is what I was thinking last night...

If I used a 16" duct for the air evacuation of the downdraft... that is 201 square inches of of area for the air to go thru the ducting... the obvious problem is that the table at 4' x 8' has 4,608 sqare inches of space to allow the suction to travel thru ... this is obviously going to leave several areas of the table with much less suction than the areas closest to the evacuation duct.

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If I put a sheet of metal about say... 6 inches below the cutting surface, but above the evacuation duct, then cut a .47 inch hole every 2 inches (this would give me 36 holes per square foot).... The total area of all of the .47 inch holes would be approximately the same as the total area of the 16 inch duct..... lets call this the diffuser???

Now if my evacuation fan has enough CFM to achieve near the maximum air flow rate for the ducting... this should require that all of the holes on the diffuser should be flowing at or near the maximum flow rate and might provide a near even distribution of the air across the table.

Another thought is that a vacuum gauge placed in the unit below the diffuser would give at least a rough benchmark as to whether the suction was effectively being forced to evenly distribute across all of the .47 inch holes.

Thoughts?

[ajclay]

Aer Rob,

A photo is worth a million dollars.... any available? Thanks, Aj

[Gillyshank]

Have you considered a water table

As most of the smoke / material is ejected out the bottom of the plate as simple tray of water positioned about an inch below the bearer bars will catch and hold most of the debris.

The depth of the water will depend on the power of your plasma.

You will be suprised how effective it is.

Water also has the advantage of being a lot cheaper than extractors and filters

[AER Rob]

AJ, What is your email address and I can send photos and literature of the AER Control Systems tables?

AER Control Systems manufactures several sizes a 42" x 50", a 42" x 76" and a 48" x 102" table. Options include two different motor horsepowers depending on the table top velocity needed, different work surfaces, standard is removable galvanized grates to handle heavy parts, table includes a back with hinged sides, to protect the main filters from sparks we offer either metal mesh or water pans, the main cartridge filters are cleaned via compressed air with a manual push of the button.

[ajclay]

Areo Bob,

That would be great to see a couple of photos of your products. My e-mail is: [email protected]

Thanks for the reply. Any and all info is greatly appreciated!

Aj