Re: Cyclonic dust collection
[img]/forums/images/icons/tongue.gif[/img] One of the guys from our church just installed one. I haven't seen it, but I recall him mentioning that they had some anti-static wire along with the suction tube? Does that sound right? One of the things I have wondered about is how the system works when I know that to a great extent cyclones are flow-specific. The Q cannot vary a great deal up or down if you are to get good separation. How do you compensate when you run a dinky tool as compared to the bigger ones? [img]/forums/images/icons/crazy.gif[/img]
Re: Cyclonic dust collection
Seeing as it will be capable of handling cattle feed I surely hope you orderd a second one for the shop!! [img]/forums/images/icons/grin.gif[/img] [img]/forums/images/icons/grin.gif[/img]
Masks are much more comfortable on a shaven face!! ehh! [img]/forums/images/icons/shocked.gif[/img] [img]/forums/images/icons/shocked.gif[/img] [img]/forums/images/icons/grin.gif[/img] [img]/forums/images/icons/grin.gif[/img]
Egon [img]/forums/images/icons/grin.gif[/img]
Re: Cyclonic dust collection
Dave, If you do it right you don't need a static wire because you don't use plastic pipe.
with just a small hole open and the rest of the blast gates closed the dust/chips from the tool will be whisked up the hose at high velocity but when this relatively small volume gets to the larger "main line" the velocity of flow drops precipitously and the chunks fall out and can clog the run.
To avoid that yoiu partially open another blast gate to let enough total air fow occur to keep the velocity up in the larger ducts. This will NOT hurt the chip/dust collectioin at the small tool.
My system will have some 8 inch ducts dropping to 5 and have various size flex hoses to connect to everything from 1 1/2 to 4 inch dust ports on various tools.
Some people try to use plastic pipe to save $ and end up with a much lower performing system. With plastic you sure need an anti-static wire inside all ducts.
Boy oh boy my DeWalt 13 inch planer makes serious sparks to your hand (or other portion of your anatomy) if the ground connection from the flex hose is not connected to the machine to use the third wire ground in the electrical supply. This is WITHOUT a cyclone, just the flex hose to a bag sort of attachment that goes over a trash can and secures with a bungee cord draw string.
If runs are very long, serious flow restriction will occur with 4 inch PVC. Main runs need to be at least 6 inch and like I said 8 is recommended (unless this is a small DIY cyclone.) If it is over one HP I wouldn't do it with 4 inch PVC. Mine is 3 HP. @ was marginal for my ap, 2 1/2 was OK but the 3 was only a couple hundred more and came with a shipping discount and a $200 free custom duct design. Seemed like the best choice and will leave room for growth.
Pat
Re: Cyclonic dust collection
[img]/forums/images/icons/tongue.gif[/img] Having spent a good sized chunk of my working like working with flowrates of non-compressible fluids, I'm fairly aware of the kinds of velocities that work and don't work. Air is a different story, I don't know very much except for the similarities that might exist as far as vortexes and entrance losses. [img]/forums/images/icons/crazy.gif[/img]
Re: Cyclonic dust collection
Actually the only difference is the Froude number CJ. [img]/forums/images/icons/grin.gif[/img]
Egon [img]/forums/images/icons/grin.gif[/img]
Re: Cyclonic dust collection
[img]/forums/images/icons/tongue.gif[/img] I have no idea what that is, except for an English historian with the same last name. I'm searching the dusty cavities of my brain to see it it was ever mentioned in discussions of open channel flow or closed conduit flow. [img]/forums/images/icons/crazy.gif[/img] [img]/forums/images/icons/tongue.gif[/img] In a vacuum scavenging system, wouldn't you WANT to maintain some turbulence to keep the soild matter from settling and lodging? Kind of the opposite of fluid flow? [img]/forums/images/icons/crazy.gif[/img]
Re: Cyclonic dust collection
Yeah, you oil pipers just aren't all that savvy WRT Reynolds numbers relating to aerodynamics and all that jaz.
Pat
Re: Cyclonic dust collection
[img]/forums/images/icons/tongue.gif[/img] Oh, we have the Reynolds Numbers in fluids as well. [img]/forums/images/icons/crazy.gif[/img] **** You know what has always astounded me is that the ROMANS could build a cross-country aqueduct such that the slope minus the friction loss due to roughness gave them the perfect water level; not too shallow, not overflowing the sides. Just to give you an idea of how tough that is, ... the great California Aqueduct project of the sixties carries less water than anticipated because the roughness factor of the concrete lining was off by just a slight squeeze of the slide rule. [img]/forums/images/icons/crazy.gif[/img]
Re: Cyclonic dust collection
Yes but... The Romans had a slightly different manner of policing the practitioners of engineering which led to greater motivation to get it right.
For example, the chief architect/engineer/designer/builder of an arch would stand below the center of the arch as the scaffolding was removed. If it fell in then the man responsible was permanently elliminated from the professional society (by being crushed by tons of stone) and his apprentices were on notice that their training was suspect and I'll bet they were careful to whom they turned for continuing training/employment.
Thus I posit that Roman engineers were highly professional, cautious, and motivated toward successful designs and realization of those designs.
In our times there are lawsuits, E&O insurance, and such but RARELY so much as a prosecution much less an execution.
Pat