Plasma exhaust fan

[square2round]

I had to move the fan a few weeks ago and duct it back outside. Nothing spectacular. The spiral pipe was existing.

You really can't notice all the fingerprints on the duct until I uploaded the pictures. I'm not worried about it.

[sirjames]

Not trying to be picky,but why not just run round for the intake?

[square2round]

We didn't have any more spiral pipe or elbows, and the boss wasn't waiting. We had the metal, and fittings were made for the situation.

[Edited by square2round on 11-12-2005 at 09:27 PM]

[rayr]

Whewww, is that a 20" throat on that riser ell??????

[square2round]

No. The elbow has 4" throats. I guess it just looks that way.

[rayr]

Noooooooooooo, not the ell that is on the square to round with the square throat. The ell with the radius throat. And althouth it is intalled horizontally, the configuration is still a riser (vertucal) ell oposed to a flat ell(Broadway ell, depending where you are geopraphically). That one has a huge throat radius.

[Edited by rayr on 11-13-2005 at 12:02 PM]

[Carnak]

Radius looks about 1.5 times the duct width, pretty low pressure drop there, probably trying to minimize loss for a turn not that far from fan discharge.

Looks good S2, next time do the job before you go to the bathroom with the playboy mag

[Edited by Carnak on 11-13-2005 at 01:01 PM]

[square2round]

Originally posted by rayr
Noooooooooooo, not the ell that is on the square to round with the square throat. The ell with the radius throat. And althouth it is intalled horizontally, the configuration is still a riser (vertucal) ell oposed to a flat ell(Broadway ell, depending where you are geopraphically). That one has a huge throat radius.

Gotcha, I understand now. I learned some new terminolgy. Thanks ray.

Carnak is correct, the throat centerline radius is 1.5 times the width of the cheek. I read in a book about having this type of centerline radius for smooth airflow and have been sticking to it...where applicable.

If the cheek is 12 inches, the radius is 12" giving you 1½ times the centerline radius.

I'll say, after I looked at the first one I cut out, it looked funny. But I assumed this was the way it's supposed to look if it was to have better airflow.

[Edited by square2round on 11-13-2005 at 01:33 PM]

[Carnak]

You can get some nice gradual bends when you are not making welded grease duct ray

[square2round]

Originally posted by Carnak
Radius looks about 1.5 times the duct width, pretty low pressure drop there, probably trying to minimize loss for a turn not that far from fan discharge.

Looks good S2, next time do the job before you go to the bathroom with the playboy mag

[Edited by Carnak on 11-13-2005 at 01:01 PM]

Thanks carns.

We were out of paper towels.

[rayr]

Originally posted by Carnak
You can get some nice gradual bends when you are not making welded grease duct ray

LOL. Been a while since we made anything that big. Usually use duct mate and turning vanes. I hate making welded square to rounds. I hide the hammers.