04-07-2010 08:43 PM
I listed this in "Tools and Tool Building" and was told I should move it. So, here it is!!
I would like to build a ceiling mounted air cleaner for my 34' x 50' shop. I want to use a furnace squirrel cage and furnace filters. I would really appreciate any info, plans, suggestions, etc in regards to this.
04-07-2010 10:59 PM
For a shop of that size you will need more then one filter, Roy.
Wood had something on that not too long ago.
Ralph also has plans and he may provide them to you, too.
04-08-2010 06:03 AM
J. I posted this on the tools forum but thought maybe you didn't see it. Something for consideration.
If you have the space and a good squirrel cage blower you may want to consider this. I made mine the same height as the work bench to increase my work area and put wheels on it to move it around the shop. It will change the air in the shop by running it when I'm working in there. With the downdraft cabability for sanding you might as well get double duty out of the unit.
04-08-2010 09:22 AM - edited 04-08-2010 09:23 AM
Hello J Roy,
As Tony stated here are two pictures of my set up and as already stated, you might want to build two of them for the size of your shop. My shop is 3840 cubic feet in size so my ceiling hung and my Jet 1100 take care of it very well.
Here are some pictures of the one I built for less than $200.00.
This picture is showing the front of the box and you will note the hasps for the drop down filter door. The filter is 24" x 24" x 2" thick and creates static electric dust collection. Note also how the entire front can be removed by the wing nuts that will allow you clear access to the blower fan.
The next picture shows the box with the drop down door closed and on the outward trunk is 8" x 16" x 3' long with a box on the end that holds three filters that can be removed and new ones put in as needed. It has worked well for me even before I got the Jet 1100 DC.
04-09-2010 05:55 AM
Here's a few pics of mine.
I'm pulling dirty air up through two 24" x 18" x 6" furnace filters. These filters are on the dusty side of my shop.
I'm dumping the clean air out of six 6" (poor-boy) diffusers on the clean side.
The squirrel cage fan and the duct work are all in the attic.
"In progress" fan and plenum.
Plenum all closed up.
It's all a little "hillbilly" but it does a good job.
It helps to have a son-in-law that works for a HVLP company.
04-09-2010 06:55 AM
That is so cool and I like the idea of the main part to be in the attic and out of the way.
Pretty good idea
04-09-2010 02:13 PM
Here is some info that might be helpful.
Here are some general rules based on Nagyszalanczy's "Workshop Dust Control" and some of my own experiences and thoughts.
The two most important criteria for an air cleaner are the CFM and the filters. You want a CFM factor that will clean the size of your shop and a filter that removes the particle size that you are concerned about.
To determine the size or required air flow, use this formula: Volume of your shop (Length x width x Height) times Number of air changes per hour (typically 6 - 8) divided by 60. This will give you an answer in Cubic Feet per Minute which is how air cleaners are measured. MOST AIR CLEANER MANUFACTURERS RATE THE CFM OF THE FAN ONLY, but there are losses due to the filters. If you are building your own or if the air cleaner you are purchasing rates only the fan, figure you will lose about 25 - 40% for filtering losses.
As important as the air cleaner size is how and where you mount it. Try to mount at about 8-10 feet above the floor (no lower than 6'or 2/3 of the floor to ceiling distance if less than 8' ceiling). Mount along the longest wall so the intake is approximately 1/3 the distance from the shorter wall. Mount no further than 4-6 inches from the wall.
The exhaust is the largest determiner of the circulation pattern. You are trying to encourage circulation parallel to the floor/ceiling so ceiling mounting is not recommended. Use a smoke stick (or a cigar) to observe and maximize circulation. Use a secondary fan to direct air to the intake if necessary. Also, consider that a standard 24" floor fan moves a lot of air and, in some shops, just positioning it in a doorway with a window or other door open can accomplish as much or more than an air cleaner. It's all in the circulation patterns.
The exhaust is the clean air so that is where you want to position yourself. Do not place the air cleaner over the a dust producer. That will guarantee that the operator will be in direct line between the dust producer and the air cleaner. The operator wants to be in the clean air stream. If the dust has to pass your nose to get to the air cleaner, you get no benefits. If you have an odd shaped shop, two smaller units may be better than one large one.
DO NOT RELY ON A AIR CLEANER TO ACT AS A DUST COLLECTOR. The purpose of and air cleaner is to keep airborne dust in suspension and reduce airborne dust as quickly as possible AFTER THE DUST PRODUCER HAS BEEN TURNED OFF.
Finally, if you are looking for health benefits, you will not find any air cleaner manufacturer that makes health claims because there are few health benefits. CATCHING DUST AT IT'S SOURCE IS THE BEST LONG TERM GOAL. Rick Peters', author of "Controlling Dust in the Workshop", makes the point that spending your money getting the dust at its source is a better investment than trying to capture it after it is already airborne. If the dust is in the air, it's going to be in your nose and lungs too. Robert Witter of Oneida Air Systems has noted that "overhead cleaners can only lower ambient dust levels AFTER THE SOURCE OF EMISSIONS IS SHUT DOWN, and they take several hours to do this. This is why they are not used in industry." The absolute best answer, if health is the primary concern, is to use a NIOSH approved respirator. The dust cleaner will help keep your shop cleaner but have minimal or no health benefits. OSHA takes this position too. They measure the number of particles per a volume and most air cleaners will not satisfy their specs.