Dust Collection - Spanning from another building.

[forty_caliber]

Looking for advice on spanning dust collection between buildings.  If I were to move my 3/4hp 2 stage dust collector to another building, how long of a run could I make without affecting performance using 4" PVC?

 

Has anyone had experience with this?

 

A minimum of 12' might be possible, but more realistically probably looking at 30'

 

.40

[Gerald]

I do not think a 3/4 will work at even 20 . 12 it might be ok but for longer run need more hp and larger pipe

[forty_caliber]

Hmmm.  That's kind of what I was thinking.  

.40

 

[PeteM]

You can do it:  use 6" pipe for the long straight run.  A typical 3/4 hp DC moves about 400 cfm at (roughly) 4" pressure (none of the mfrs publish enough info to properly engineer this).  If you use 4" pipe @ 400 cfm, 30' of duct, that eats 3" of pressure, which means you get a lot less than 400.  If you use 6", that same 400 cfm uses 0.4" pressure, which will probably work in terms of pressure.  The problem:  6" duct at 400 cfm has a velocity of 2000 (feet per minute).  What happens next depends on what kind of dust you're creating.  Fine dust will still transport at 2000, but larger particles might drop out in the duct.  Right where you transition from 4" to 6", use a "wye" fitting (branch in the up direction), cap it, and then you can periodically rod it out to loosen the big hunks down the duct and into the 4" section on the far side of the 6" (with the fan running, rodding out the hunks--if any--will move them enough to capture and entrain).  Part of the trick here is to employ a straight 6" over the long run.  Try to avoid any bends because this is where the "chunks" will hang up (tech speek:  downstream of any elbow/bend/transition, there will be low air velocity areas of the duct, and low velocity allows precipitation).  

That help?

[Fred W. Hargis Jr]

I'm thinking the same as Gerald...it's just enough DC. Does it do the job you want as it is?

[forty_caliber]

2 minutes ago, Fred W. Hargis Jr said:

I'm thinking the same as Gerald...it's just enough DC. Does it do the job you want as it is?

It works well enough.  The actual problem is emptying the chips.  Currently the system is installed in the "loft" 8' over the floor.  It requires a ladder to get to the container, down the ladder with 30 gallons of chips.  Then back up the ladder with the container.  I'm not really supposed to be on a ladder according to the doc.  It's not all that heavy just trying to eliminate some risk. 

 

Moving the system onto the ground is the right thing to do.  There isn't room on the shop floor for it.  There is room in the other building. 

 

.40

 

[knockonit]

reconfigure and put chip holder on ground floor, gravity could assist in the movement once it hits the collector, just a thought, i too have the afliction to have to stay off ladder, my solution was a ladder on wheels platform type, used in warehouses, helps me keep me balance when wrestling good off the mezzanine takes up some room, but i move it to the patio when not in use, love the guard rails, i'll post a pic, later today,

good luck with solution, dust collection the bane of wood working

rj in az

[John Morris]

Great topic .40! With some informative answers.

Moved topic to Machinery and Tools Forum

[Fred W. Hargis Jr]

3 hours ago, Fred W. Hargis Jr said:

I'm thinking the same as Gerald...it's just enough DC. Does it do the job you want as it is?

I meant to type "it's just not enough DC....." as usual my thought process outran my fingers. It's very hard for me to imagine my thought process can outrun anything, let alone my fingers.

Edited February 22, 2023 by Fred W. Hargis Jr

[HandyDan]

What about a little bump out on the side of the building to house the DC.

[forty_caliber]

23 minutes ago, HandyDan said:

What about a little bump out on the side of the building to house the DC.

I'll have to think that through but it's a great idea. 

 

.40

[PeteM]

Something to keep in mind:  when you move the DC out of the exhausted environment, the air is no longer recycled back into that environment (room), and so you have air, often uncontrolled in temperature and cleanliness, entering the room to compensate.  Often, that's hot outside air, except when it's cold outside air.  Can you duct from the loft to the floor and put the dust container on the floor or attached to the wall?  Also, a pulley to avoid carrying the bag down the ladder?  [And my empathy:  I had to give up ladder use in about '07; an annoyance in my profession.]

[Masonsailor]

Gerald is probably right. 400 CFM is probably not going to be enough. One of the HF 2 hp models might be a better solution. I picked one of mine up on CL for $100. That will give adequate cfm for that length of run. As far as building the closet on the outside of the building just insulate it as good as your shop and provide a return air to preserve your heated or cooled air. I’ve done this on a shop before and it worked very well. Install a standard HVAC filter on the return air to increase the filtration. 
Paul

[forty_caliber]

17 minutes ago, PeteM said:

Something to keep in mind:  when you move the DC out of the exhausted environment, the air is no longer recycled back into that environment (room), and so you have air, often uncontrolled in temperature and cleanliness, entering the room to compensate.  Often, that's hot outside air, except when it's cold outside air.  Can you duct from the loft to the floor and put the dust container on the floor or attached to the wall?  Also, a pulley to avoid carrying the bag down the ladder?  [And my empathy:  I had to give up ladder use in about '07; an annoyance in my profession.]

I might be able to rearrange floor tools / tool cabinet to make a little room for the container on the floor.  My shop is only 12x16 and full to the gills.  

 

That grinding noise is the clutch slipping in my head. 

 

.40

[PeteM]

2 hours ago, Masonsailor said:

 400 CFM is probably not going to be enough. 

As I recall, the Industrial Ventilation manual calls for 500~600 cfm on a table saw (they have lots of tools catalogued; and PICTURES!!!).  But lots of people use shop vacs, and those are about 100 cfm (big variances, of course).  Exhaust is really a "how high is up" game.  Some is better than none, etc, etc... Pretty soon you're sucking in  the garage door.  A lot of exhaust efficiency depends on how the tool is constructed, connected, enclosed.  Remember too that exhaust is trying to serve two purposes:  (1) health protection (fine or poisonous particles kept out of the lung) and (2) clean up (in commercial apps, this means fire protection since dust piles can be made to combust).  Lungs are vulnerable to the small particles, but these are pretty well captured even with low air flow; the big hunks are harder to stop, but are more of a housekeeping function than health threat.

[Gerald]

The more duct you have the more resistance and that means less air flow. Now if all you need to do is not climb ladder there is a fix. My DC is in attic in sealed room with a filter over a return air to get conditioned air back into shop. I two tired of the ladder business and built my own box for chips. this got a lot but not the small stuff.

 

 

 

So I eventually go a 5 inch Dust Deputy to collect the fines and make only rare tripe to attic now. I cut windows in DD and the chips box to view capacity. The DD has a 5" hose to attic and that also increased suction in the shop.

 

 

Something like this may solve your problem but you still have an underpowered DC IMHO. Hope this helps some.

[forty_caliber]

I'll get there eventually, I need to sell the PM 2014 to get it out of the way.  After that move the ShopSmith and it's accessories out to the shed instead of the DC.  I haven't even turned it on in over a year and I have no plans to go back into flatwork. I will focus the shop building away from a general use "SHOP" to more of a turning studio.  I'm enjoying turning  much more than I ever did working in the flat and I'm better at it.  

 

Those two things will allow some floor space for one of these or similar.  My current DC has been in use for at least a decade or more, has always kind of worked but has no Tim Taylor...simian grunts...Ugh Ugn Ugn.  I'll just leave the old one in place where it is.  It will make a good backup.  

 

.40

[HandyDan]

1 hour ago, forty_caliber said:

I haven't even turned it on in over a year and I have no plans to go back into flatwork

 

Turning is addicting ain't it?