Venting dc outside

[Michael W. Clark]

Well let me ask it this way:

If you pick it up and set it back down... say, 100 times. (lets assume in the same spot)

Did you do any work?

Carl,
Work = Force x Distance. If you apply a force to an object and move it, then work was performed. Even if the object returns back to the same place it started, it still traveled a distance.

I wasn't trying to be smart when I posted this, but wanted it to lead into the statement by Phil and others. Moving the air around in the shop takes energy and a large percentage of the electrical input of the DC motor goes into moving this air. A relatively small percentage is converted to heat due to the electrical inefficiency of the motor and drive losses at the fan.

As far as the air being heated from duct friction, I just can't buy into it without more thought or emperical data. I understand the concept that the duct friction is imparting heat into the air, but honestly, I have never measured a temperature rise in the airstream between two points when there was just ductwork and no outside influence.

Mike

[Carl Beckett]

Ya. It's an old trick physics question. The vertical motion and going back to the same energy state ( potential energy level the same ) means no work was done. Arguably the same for horizontal displacement inside of the control boundary. ( people here seemed to want to argue about physics and math so thought I would join and stir the pot!)

To Paul: vent outside. But, a cyclone might be too much and still keep the air flow up, so a simple separator would be a better choice if you can't send the chips outside. If you can.... Just do that.

[Phil Thien]

Ya. It's an old trick physics question. The vertical motion and going back to the same energy state ( potential energy level the same ) means no work was done.

I'm not getting you. Work is a scaler, not a vector. As soon as you've applied a vertical force (to move something vertically), you have done work.

[Leo Graywacz]

I'm not getting you. Work is a scaler, not a vector. As soon as you've applied a vertical force (to move something vertically), you have done work.

As soon as you move any object that was at rest in any direction you have done work.

[paul cottingham]

To Paul: vent outside. But, a cyclone might be too much and still keep the air flow up, so a simple separator would be a better choice if you can't send the chips outside. If you can.... Just do that.

I figure even with a cyclone, what I probably gain from getting rid of my bag filter will make doing this worthwhile. Or am I missing something? I would love to use a Wynn filter, but getting them to Canada (especially Vancouver Island) is really tough. He won't ship over the border, and I can't say I blame him. its around $160 to leave the island so getting them drop shipped is very expensive as well.

[Carl Beckett]

I figure even with a cyclone, what I probably gain from getting rid of my bag filter will make doing this worthwhile. Or am I missing something? I would love to use a Wynn filter, but getting them to Canada (especially Vancouver Island) is really tough. He won't ship over the border, and I can't say I blame him. its around $160 to leave the island so getting them drop shipped is very expensive as well.

I added a cyclone to a 2hp blower system, vented outside, and it's 'marginal'.

The cyclone needs a little more flow rate than I am getting

[Carl Beckett]

I'm not getting you. Work is a scaler, not a vector. As soon as you've applied a vertical force (to move something vertically), you have done work.

Yes. That's all part of it. Begins a debate on the boundary conditions, timeframe in question, etc. You can break it down and get different answers depending on how you bound the problem. That's what was happening in this thread which was causing some of the difference in perspectives.

[Michael W. Clark]

Yes. That's all part of it. Begins a debate on the boundary conditions, timeframe in question, etc. You can break it down and get different answers depending on how you bound the problem. That's what was happening in this thread which was causing some of the difference in perspectives.

The statement that started this was that all the electrical energy consumed by the motor was going to heat the air. The air, when it is moving, has kinetic energy, this kinetic energy came from the electrical energy provided by the electrial power to the motor. Therefore, part of the electrical energy supplied to the shop, did not turn into heat energy, it turned into kinetic energy in the air. The air "wants" to be at rest, the energy being supplied from the motor/fan is causing it to move.
Mike

[paul cottingham]

I added a cyclone to a 2hp blower system, vented outside, and it's 'marginal'.

The cyclone needs a little more flow rate than I am getting

Bear in mind my shop is tiny 9x20. Most of my equipment is in the "back" so my runs are 10' at most.

[Jeff Miller]

Take a piece of 1' Pipe and blow threw it.......Now hold some rags over the end opposite your mouth and blow threw the pipe.......that's called back pressure ...........you figure the rest out




JEFF

[Leo Graywacz]

Hey...the air out the other end is warm

[Jeff Miller]

Hey...the air out the other end is warm

I would hope so.....otherwise you better start digging


JEFF

[David Cramer]

So to be clear: If I am in Michigan and vent outside, with a louver to keep out cold air in the winter, and I don't run it for long periods (5 minutes maximum at a time), am I okay or am I losing tons of heat?

I have a window to crack when it's on for the needed air exchange.

The part that goes outside through the wall will have a sweeping 90 and then straight down about 5-6 feet with a screen on it to keep out the unwanted. In addition, the part on the outside will be boxed in with ridged insulation for noise and wrapped in vinyl siding to match the exterior. I would think this would really minimize the noise and the minute dust would go into a box or rock pile and mother nature (rain) would send it through the rocks.

Am I doing it right and did I follow this thread correctly in terms of heat loss, air exchange and venting it outside?

Thanks, David