Replies

1. 
   Jeff | Jun 18, 2004 02:38pm | #1

   I have a small 1 hp right at my sanding table that feeds into my main cyclone pipe.

   Mostly to increase the pick-up at the table's large area and overcome the long pipe run.

   Seems to work fine.

   Jeff

2. 
   Bustos963 | Jun 18, 2004 03:32pm | #2

   Hello Ewe,

   I think there are several problems with what you are proposing. I think you should: 1) design and build a single large system to handle the entire shop; or 2) run two seperate systems using the two blowers, or 3) reconsider the idea of exhausting the air outside and build a system that traps the fine particles and shavings.

   I think that trying to run two blowers in line is going to be inefficient, set the blowers up for impact damage, create a potential fire hazard, and finally, may create some funbky airflow problems in the piping between the two blowers. Just my opinion.

   Bustos

3. 
   RickL | Jun 18, 2004 03:59pm | #3

   I see no problem but I would pose the question to a couple of companies that specialize in dust collection like Oneida and Air Handling Systems. At least then you could get an engineers take on it as opposed to an opinion from people of unknow qualifications.  I do purchasing and keep our shop running and have a group of experts in various fields such as motors, tooling etc., I can confer with for in depth expertise.

   
   

   ---

   Edited 6/18/2004 9:03 am ET by rick3ddd

4. 
   DougF | Jun 18, 2004 04:31pm | #4

   Ewe,

   The basic question is one of CFM at the dust collection port.  If the 1hp DC provides less CFM at a given port, why would you restrict the air flow by placing it in service at that location?  If, at a given port, the 1hp DC provides greater CFM than your large unit, your have an iadequate aid handling setup either in the basic design of the lines and drops, leakage, the capacity of the larger unit, or all of the preceeding variables. 

   However, having said this, if the 1hp DC performs better on a single line that dumps into a larger line with greater CFM , the Ihp unit could be staged at that intersection to provide a boast up to the larger line.  If you did that I would isolate that "1hp line" with a blast gate between the 1hp DC and the intersection with the larger system.  Of course, you can also simply keep the weaker line isolated to the 1hp DC rather then using the larger system as a dust chute.

   As suggested by others, I would call O'neida or Aid Handling; both firms offer great technical advise.

   Doug 

5. 
   ukdave | Jun 18, 2004 06:05pm | #5

   By placing two fans in series, you are able to add the static pressure produced by each fan together.

   In my work with pumps, I run several in series (in-line) and the key is to not have a pump further away running at a higher flow-rate.  Based on my experience with pumps, I wouldn't recommend putting the smaller fan in front of the larger fan.

   Agree with the others to discuss with a technical person.  Putting the smaller fan in front of the other could create bad turbulent flow conditions.

   Dave

1. 
   Elcoholic | Jun 18, 2004 06:36pm | #6

   To work efficiently the two blowers will need to be complimentary.  I suspect using 2 stand alone blowers in series isn't the right way to go.  I can't say I've ever seen squirrel cage blowers in series.  I don't think they're designed for pressure at the inlet.  The second blower may need to be an in-line axial blower to be effective but I can't say I've seen one of those for this service and they are expensive.  You could certainly have a larger system draw from the chip container of primary system, but running two systems is at least electrically less efficient than a single larger system properly designed.  At 240V a 3 hp motor draws 3 amps less than a 1 and a 2 hp motor.John O'Connell - JKO Handcrafted Woodworking

   The more things change ...

   We trained hard, but it seemed that every time we were beginning to form up into teams, we would be reorganized.  I was to learn later in life that we tend to meet any new situation by reorganizing; and a wonderful method it can be for creating the illusion of progress while producing confusion, inefficiency, and demoralization.

   Petronious Arbiter, 210 BC

6. 
   GHR | Jun 18, 2004 06:45pm | #7

   If it works, it works.

   It is not worth anyone's time to do any type of analyis of the situation.

   My Dewalt planer has a built-in fan that blows the chips into the DC pipes. (Same idea that you have.)

1. 
   EWE | Jun 19, 2004 06:23am | #8

   Thanks everyone. I really didn't provide adaquate context for the question I asked. I'll just take the best advice offered and call the pros.

   Thanks,

   eliBrookfield Woodworking

   Cushing, Maine

1. 
   DougF | Jun 21, 2004 03:45pm | #9

   Ewe,

   Please post their response.

   Doug