Installation in progress

[jstipins]

Hi everybody,

I'm not quite done with my installation yet, but here is an in-progress photo.

The enclosure lives in a storage space behind my garage. My shop is in the garage, through the door on the right of the photo.

I built a standalone enclosure out of 2x4s using standard platform framing, sitting on a sheet of rubber just to protect it from any moisture in the concrete floor. I used a double top plate to square it up, so the total height is 97.5" before the ceiling/lid. I sheetrocked the inside with 5/8" gypsum. The interior dimensions after sheetrocking are 28 x 41.25".

Since taking the picture, I used Roxul Safe N Sound mineral wool batts to insulate the walls, and then hung sheetrock on the exterior back and sides. The front is going to be 5/8" plywood, with a simple door made of 5/8" plywood over a 2x4 frame, filled with Roxul.

The ceiling/lid is going to be a similar construction to the door: 5/8" plywood over a 2x4 frame filled with Roxul. The point is that the lid needs to be removable if I ever need to get to the motor.

I mounted two 2x4s on the interior that are level (which is not parallel to the floor, in this case!) and then used two more 2x4 cross pieces to make a rectangular frame to hold the cyclone mount. I added some strips of 1/2" plywood to keep things in place once I knew where I wanted it.

The intake is going to be cut through the right side; I'm going to use flexible duct just to get through the wall of the garage, to help isolate vibrations. The exhaust is going to be through a cutout in the lid over the motor, and then through many feet of flexible HVAC, which will then return to the shop. I'm hoping that this will be sufficient airflow to keep the motor from overheating.

Anyway, this whole thing was motivated by a desire to isolate the noise, which is why I'm posting here. Obviously it's too soon to tell how well it works, since the enclosure isn't finished. But already I can say that the low frequency noise does not travel upstairs; I think this is because the enclosure does not touch the frame of the house. I'm optimistic that the whole thing will be quite effective once I finish the door and lid.

I'll keep you posted!

-JS3

 

[McRabbet]

JS3,

Your progress looks like it will work well to isolate the noise -- having the return filtered air exit near the motor should aid in removing motor heat build-up as planned and the flexible HVAC duct (use at least 8" ID) should help attenuate blower noise. I suspect your remaining concern will be to monitor the bin to be sure it doesn't overflow into your filters. I assume you are aware of the bin sensor system I sell that will alert you to that hazard; if not, feel free to contact me for details.

 

[jstipins]

Hi McRabbet,

Thanks very much, I do have the 8" ID flexible insulated HVAC duct to use for the return. As far as the bin monitor, that's something I'll add later if I find it annoying to check the bin before using machines... I'm the only one working in my shop, so I'm not very concerned about accidentally overflowing the bin, but maybe I'll change my opinion on that over time.

Right now my main question is about something I've seen in some Bill Pentz duct designs. I've seen an example of his start with two or three feet of flex duct coming straight off the intake, before switching to normal ducting; the idea being to isolate vibrations from the cyclone and to prevent the whole duct system from vibrating. But I've also seen recommendations that the first length of duct off the intake be as smooth and straight as possible for at least 10 diameters, so that the air flow is as smooth as possible going into the cyclone. Which one would you say is more important? Or, can both be achieved, as long as the first 2-3' of flex duct are as straight as possible?

Thanks,
-JS3

 

[McRabbet]

Ironically, I just answered a similar question over on Sawmill Creek -- if the entry duct to the intake ramp on your ClearVue is a 3-4 foot straight section, there will be less turbulence in the dust-laden air coming into the ramp and thus better separation in the cyclone. The use of Flex or elbows always cause some turbulence and will reduce the efficiency of the cyclone's separation by at least a few percentage points depending on the amount of bending in the flex and distance to the intake. (Look at Bill Pentz's data to see the static pressure loss of flexible duct versus straight pipe.)

In my opinion, a flexible coupling like this one (called a Fernco coupling) provides the needed vibration isolation and can be fitted to allow a slight bend in duct direction if needed. They are available at most home centers and can be clamped onto PVC or metal duct if needed.

 

[jstipins]

Thanks very much, that coupling looks like a much better idea than a length of flex duct for isolating vibrations.

Referring to the picture of my installation, you can see that I don't have 3-4 feet between the intake and the wall that the duct will have to pass through. So it sounds like I should use a length of straight duct through the wall, through the side of the enclosure, and to the intake; isolate that duct from the garage wall by wrapping it in rubber or something as it passes through the wall; and then use that flex connector to isolate the vibrations from the rest of the ductwork. Is that what you're recommending?

Thanks for all your help!

-JS3

 

[McRabbet]

That plan should work well and some foam or fiberglass insulation around the duct penetrations should isolate any vibrations. Looking at the angle of the intake, you might want to use the Fernco fitting at the intake, run a straight section through both walls and then use a 22-1/2 degree elbow to drop the duct to be parallel to the ceiling in your shop.