I'm just joining this forum after having read most of Bill's website and studied what I can find online about dust collection. I gave up woodworking as a career 30 years ago due to allergic reactions to wood dust. I had a typical 1-2 HP "bagger" system that mostly just redistributed the fine dust around my shop. Being in northern Vermont I kept the doors closed a lot of the time. Now I'm getting back into some shop work and plan a larger shop when I build our new house next year. In the mean time I am using rented shop space and wanted to avoid wasting money on a temporary system. My work will only be hobby level, and I should be able to open the garage doors quite often; but still I've decided to implement a high-quality collection and filtration system.
So I've ordered the CVMAX cyclone, the 16-inch impeller, and two 300SF NANO filters. I've separately purchased a 5 HP 3-phase motor and a VFD. Although my current and my planned future shop both have 10-ft ceilings, I want the system to be portable, at least at first, so I want to place the motor/blower down low.
I'm thinking about two basic options: 1) place the blower "upside down" just above the floor, with a 9-inch duct connecting its inlet to the cyclone's outlet. This duct will look like a candy cane, or an upside-down letter J. Then construct a plenum at the blower's outlet that extends horizontally beneath the two filters, which would sit side-by-side. This option seems to be the most straightforward, but I'm a little concerned about the additional pressure drop due to six or seven feet and 180-degrees of elbows in the 9-inch duct.
2) The second option would be to construct a horizontal plenum to join the cyclone outlet to the tops (internal inlets) of the two filters. Then enclose the filters in a box, and connect the blower's inlet to the bottom of the box, which would be external to the filters. This means the blower's outlet would be atmospheric pressure, and the suction at its inlet would be at a lower mean pressure than in normal installations. The advantages of this approach would be (I think) less overall pressure drop, and with the entire system at negative pressure, no chance that any leak could blow dust into the shop. Since the net negative pressure would be less than half a psi (3% of one atmosphere), I don't think there would be much effect on the blower's performance. I'm at 5000 ft, so the air density here is already some 17% lower than STP (hence the 16" impeller for a small shop system).
While I've thought up several "clever" ways to enclose the filters, I'm sure option 2 would require more fabrication effort than option 1, and the cost would probably be a wash. I'm also concerned about noise with option 2. The blower outlet would be unmuffled, and I might need to construct a huge transition from the blower outlet flange to a rather large area exit opening, to avoid a serious air blast across the shop. In option 1, as with all conventional installations, the filters must serve as diffusers, since they come after the blower.
So I'm wondering whether any readers here can offer advice on this question.
So I've ordered the CVMAX cyclone, the 16-inch impeller, and two 300SF NANO filters. I've separately purchased a 5 HP 3-phase motor and a VFD. Although my current and my planned future shop both have 10-ft ceilings, I want the system to be portable, at least at first, so I want to place the motor/blower down low.
I'm thinking about two basic options: 1) place the blower "upside down" just above the floor, with a 9-inch duct connecting its inlet to the cyclone's outlet. This duct will look like a candy cane, or an upside-down letter J. Then construct a plenum at the blower's outlet that extends horizontally beneath the two filters, which would sit side-by-side. This option seems to be the most straightforward, but I'm a little concerned about the additional pressure drop due to six or seven feet and 180-degrees of elbows in the 9-inch duct.
2) The second option would be to construct a horizontal plenum to join the cyclone outlet to the tops (internal inlets) of the two filters. Then enclose the filters in a box, and connect the blower's inlet to the bottom of the box, which would be external to the filters. This means the blower's outlet would be atmospheric pressure, and the suction at its inlet would be at a lower mean pressure than in normal installations. The advantages of this approach would be (I think) less overall pressure drop, and with the entire system at negative pressure, no chance that any leak could blow dust into the shop. Since the net negative pressure would be less than half a psi (3% of one atmosphere), I don't think there would be much effect on the blower's performance. I'm at 5000 ft, so the air density here is already some 17% lower than STP (hence the 16" impeller for a small shop system).
While I've thought up several "clever" ways to enclose the filters, I'm sure option 2 would require more fabrication effort than option 1, and the cost would probably be a wash. I'm also concerned about noise with option 2. The blower outlet would be unmuffled, and I might need to construct a huge transition from the blower outlet flange to a rather large area exit opening, to avoid a serious air blast across the shop. In option 1, as with all conventional installations, the filters must serve as diffusers, since they come after the blower.
So I'm wondering whether any readers here can offer advice on this question.
