Clearvue Pentz EF5 / Nordfab dust collector build

[Aaron Inami]

This has been a 3 month project, but I have now gotten everything complete and finally able to document everything that I have found. Obviously, from the title, I went with a 5HP Clearvue Pentz EF5 dust collector using Nordfab ducting. Here’s pics of initial parts layout. Most of the build goals have to do with addressing sound and I’ll describe each section in detail.

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Cyclone Resonance

The cyclone is made from heavy 16 gauge steel. Since steel is still quite flexible at this thickness, there is a lot of resonance generated from certain areas. I applied a layer of Dynamat Xtreme to the inside of the section where the impeller runs. This area generates a whole lot of turbulence from the movement of the impeller.

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I also applied 1/8” Sorbothane sheets to the intake port. It resonated pretty good when I tapped on the sides. I did also put some Sorbothane on the back side of the first 11” section of 8” duct since it also had a lot of movement vibration.

https://www.amazon.com/dp/B019GBG97Q...roduct_details

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[Aaron Inami]

Exhaust Silencer

All the videos I watched of Clearvue cyclones revealed a very loud high pitched tone. In effect to reduce this, I went with a Fantech LD8 duct silencer. This was only $128 from SupplyHouse.com.

https://www.supplyhouse.com/Fantech-...cer-for-8-Duct

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I cannot fathom why the Nordfab silencers are so freaking expensive ($1178 for an 8” galvanized steel silencer). The Nordfab might be 5” longer, but I cannot see anything in the design to justify over a thousand dollars (unless you want a silencer that has the quick-connect ends). If any, the Nordfab might perform 5-10% better, but still not worth the money in my opinion. To connect this to the cyclone, I had to do some tweaks. I had to cut off the rubber gasket that was glued onto the end of the silencer because it was preventing me from inserting the end far enough into the output port. I used a Nordfab “no-leak” o-ring as well as a standard o-ring on the silencer end and then attached it using a normal Nordfab quick-connect clamp. I had to push the o-ring into the clamp while holding tension on the clamp to get most of the o-ring inside, then closed the clamp all the way. It works great with an excellent seal. It was easy to push on the standard 8” flex-hose on the other end of the silencer.

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Additionally, I also installed a Oneida 13” Stacking Sound Filter ($199).

https://www.oneida-air.com/dust-coll...g-sound-filter

To mount it, I called Clearvue and ordered another round filter clamp w/hardware. I just applied silicone to the top of the filter and placed this silencer down on it and secured it with the round clamp. The Clearvue hose flange was siliconed and screwed onto the top of the Oneida silencer.

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[Aaron Inami]

Exhaust Airflow Noise

To further reduce the sound, I built some 6 foot tall sound panels to go around the exhaust filter. I used 2” Owens 703 insulation and wrapped it with “white” Guilford of Maine fabric. This stuff is available from an online retailed named “ATS Acoustics”.

https://www.atsacoustics.com/cat--Fi...ards--106.html

https://www.atsacoustics.com/guilfor...ne-fabric.html

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The individual panels can be easily removed to allow for blowing out and cleaning the filters.

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I had to double-layer the fabric on visible parts to prevent see-through. After running the dust collector, in hindsight, I should have used Rockwool Comfortboard 80 instead of Owens 703 for this because the filter exhaust noise is all low frequency rumble at this point. The Rockwool 80 has better low frequency absorption (I may build new panels at some point in the future.

[Aaron Inami]

Ducting Resonance
One thing I found out after installation was that any contact the duct has with the wall will cause the wall itself to resonate (this was also the reason I purchased the floor-stand option instead of the wall-bracket option on the cyclone). The resonance is in the 30-60 Hz area and it makes the wall into a big subwoofer (the Nordfab duct actually has a LOT of movement resonance caused by the cyclone impeller and wind turbulence). This increases the bass noise/pressure if the room and also causes ear and body fatigue. To get rid of this, I put a ½” rubber foam mat against the wall to isolate the duct away from the wall anywhere that it had a contact point (these were just garage floor work mats). This worked great. I also have small foam pads between the blast gates and the wall where it would also contact.

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I used the Nordfab Gripple pipe hangers because that ended up being the easiest way to secure/hang the duct system. I bought some stainless-steel coat hooks from Home Depot. This matched the color of the duct/cable and looks more professional then using that cheap duct strapping.



Duct Clamps
When I initially purchased all the Nordfab parts, I got the duct clamps with the standard Nitrile seal (since it was the cheapest). After everything was installed, I discovered that I had actually installed the clamps incorrectly. When installing the clamp, I did not pull out that small extension of seal to tuck it inside the clamp area. Since there was now a double-layer of seal on the over-lap point, it lifted the overlap up even higher and also presented a small gap/hole at the overlap point. When the static pressure of the air gets to a high enough point, it will suck air through these gap/holes and you will get air noise. This seemed to have louder noise with the larger clamps such as 8”. The big 18” clamp that held the cyclone together had a really bad noisy air leak. It was so bad that I could squeeze a towel onto it and block the noise.

For education, these pictures show the WRONG and RIGHT way to install a Nordfab duct clamp. You have to remember to peel up and tuck that little extension of seal into the inside of the clamp area before tightening down the clamp.

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As a result, I had to order enough seal to re-do all my clamps. It allows me to check out and experiment with the different seal types. I ordered the seal from here:

https://nordfabductwork.com/nordfab/...l-clamp-seals/

Below are the three different seal options.

Left – black nitrile seal.
Middle – Orange silicon seal.
Right – White Gortex/PTFE seal.

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In working with the seals, the Gortex/PTFE was the biggest pain in the butt. It is, basically, a very thin Teflon strip (0.02”). It was difficult and time consuming to stick onto the inside of the clamp. It is impossible to install one of these clamps properly by tucking the seal inside “by yourself” because the seal is so thin it just flops around. You really need 4 hands when installing the clamps because you need somebody else to hold/align the duct while you tuck and tighten the clamps. The nitrile/silicon seals are 1/8” thick (6.25 times as thick as the PTFE) and I could easily tuck and tighten the clamps myself while holding/aligning the duct.

The Nitrile seal is rated for a maximum temp of 194 degrees F, with continuous temp of 158 degree F.

The Silicon seal is rated for max of 400 degrees F. The silicon has a higher tensile strength since it was harder to tear apart with just my fingers. I have a feeling that the Nitrile seals will degrade faster over time and are not as durable (but they are cheaper). I chose to go with Silicon seal for my entire system.

The Gortex/PTFE was such a pain in the butt and the thin seal means that your duct has to be perfectly aligned. You can’t have a slightly off-angle connection because the seal doesn’t have any compression and would allow a gap/leak. I had to test it without tucking in the end and it also had a small air leak at the overlap point. In my opinion, the only real reason to get the Gortex/PTFE seal is if you absolutely need that max 600 degree F temp capability.

[Aaron Inami]

VFD Drive

I chose to get a 3-phase motor on the Clearvue dust collector so that I could control airflow as well as noise. This was one of the significant drivers of noise reduction in my system. I chose to go with the ATO 5HP single-to-three-phase VFD at the $300 level.

https://www.ato.com/5hp-vfd

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I did not want to get the cheaper Chinese VFDs available on Amazon, but I also did not see myself spending upwards of $600-800 dollars for the well-known higher end VFDs. Additionally, the 160 page PDF manual (in real English) available for this VFD is absolutely excellent. The adjustment knob on the front panel of this unit actually works to control the speed (on some of the Chinese VFDs, the knob does absolutely nothing).

I did have to swap around 2 of the 3 output wires because the impeller was rotating the wrong direction on my initial installation. It's a guess-work on wiring when you connect a 3-phase motor.

Once powered on and in use, I found that the small cooling fan on top of the unit actually was pretty loud and annoying. While not anywhere loud enough to cause hearing damage, it did add to the noise in the environment. The fan runs when the unit is running the motor and continues to run for about 3-5 minutes after motor shutdown. I went ahead and build a noise muffler box enclosure. This also protects the exposed wiring at the bottom of the unit. The muffler box works extremely well (you can still hear the fan noise, but it is significantly reduced).

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I did customize several parameters. They are as follows:

P0.02 - Running Frequency Set -- 50.00 Hz

P0.06 - Max output freq. - 63.00 Hz

P0.17 – Acceleration Time – 10.0 (seconds)
P0.18 – Deceleration Time – 10.0 (seconds)

P0.19 – Upper limit freq. – 63.00 Hz
P0.20 – Lower limit freq. – 40.00 Hz



I set 40 hz as the lowest running level to ensure the motor ran fast enough for cooling and general operation. I set max at 63 hz to allow me just a little bit of boost when I need it or when I want to “clean the pipes”, lol.

The 10 second acceleration time was set based on findings from Chris Parks (I think). Based on his testing, anything less than 10 seconds would cause the motor to pull more amps (on startup). Anything more than 10 seconds did not show any benefit in reducing amp pull (on startup).

[Aaron Inami]

Complete Duct System

This is what the system looks like at this point. The drops may look like they are all smooshed together, but I wanted to get as much straight pipe for the main before it connects to the cyclone inlet (best effort to reduce turbulence before air enters the cyclone). It’s not the recommended length, but best I could do. The dead-end branch toward the ceiling is to allow for expansion. I will be running duct across the ceiling to the other side of my shop for more tools (i.e. planer/jointer). I'm running an 8" main trunk with 6" branches/drops.

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If you look closely, you can also see that I installed one of the Oneida bin level sensor with that big red light. In testing this, I was able to adjust the sensor properly after filling the drum with enough sawdust.

The system result is just excellent. At high speed (63 Hz on the VFD) it sucks the crap out of anything. At the lowest speed of 40 Hz on the VFD, it actually pulls more air than my old 1.5HP Jet 1100 dust collector at full speed. I found that 40 Hz is perfect for table saw (one drop going to both saw and the over-head blade guard dust collector). When using the edge sander, I might turn it up to 50 Hz. With this system, you really only need to crank it up full to 60 Hz if you are running two tools at the same time. However, this system is not enough to have 3 drops open at the same time (i.e. three wood machines at the same time).

The system is actually very quiet (considering) when running at 40 Hz. Even at 50 Hz, the system is considered quiet. It does get kind of loud at 60 Hz.

[chris weir]

Very impressive! I too have a Jet 1100 and want to upgrade to a cyclone.

[Tom M King]

Thanks for posting this!

[Kyle Stiefel]

Aaron,

Great documentation and you obviously put considerable thought into this. I have the same unit but am not operational yet, hopefully soon following the elusive electrician. I didn't even consider things like the 3 phase variable RPM, well done.

Did you happen to take any pre and post decibel readings? Probably not as you put the Dynmat in the cyclone but would be interesting. It was a good time getting the motor up there by myself.

[Aaron Inami]

Sorry, I did not take any decibel readings at all. I'm not setup to do lab testing and it would actually take way too much time to run the machine, measure, and the switch configurations. This was a time consuming project anyways, lol. The only thing that I really did not plan ahead for was the wall resonance from duct contact, but that was an easy fix.

Though, I will say that I was impressed on how quiet this system was after all my individual item efforts. I was slightly concerned that it would turn out to be too loud. The dynamat and sorbothane stuff came from my 25+ years in the audio hobby dealing with acoustics (as well as the Owens 703 sound panel stuff).

For reference, if you guys want to re-seal your duct clamps:

A 6" clamp requires 21-1/4" of seal.

A 8" clamp requires 29" of seal.


I had a couple friends help with the motor/impeller installation. As you can see, I only have a few inches clearance between the motor and the ceiling. We tried tipping the stand a little against our step-ladders, but that wasn't enough. In the end, I strapped the top part of the cyclone down to the stand so that it held together. Then I tipped the entire stand/cyclone down and rested the frame on my router table. This allowed us to mount the motor almost sideways. Then we just muscled the cyclone/frame back upright.

[Tom M King]

db ap for iphone seems to work pretty good. I don't know how accurate it is, but it makes good comparisons.

[Chris Parks]

Aaron, you have done well and the difference in working in a clean workshop will surprise you, many people who change to a large cyclone comment on the way the workshop becomes a nicer and more enjoyable place to be in. The resonance puzzles me that maybe because our installations in Oz use PVC pipe and are in standalone workshops as Australian homes do not have basements. My next cyclone is going to have a 17" impeller with 3 phase VFD control for speed and it will be interesting to see how slow it can be run for effective dust control. The noise level will definitely be very low which is the whole aim of the experiment and I should be able to monitor what speed to run it at using a dust level meter. It may be a good idea for you to check dust levels against the speed you run your cyclone at to give a better idea of what is happening.

[Aaron Inami]

The resonance subwoofer effect is documented and shown in this video (the main reason I went with the stand):

https://www.youtube.com/watch?v=uOoPJZsav4s


I suppose it really depends what you mount your cyclone and duct to. If you are mounting to concrete wall, you won't have this problem. However, the drywall we have here in USA will flex and resonate from sound pressure and physical movement pressure. It's entirely possible that those stand alone workshops in AUS do not have walls that are susceptible to this effect. I used Nordfab duct which is really stiff by itself and between the quick-connect clamps. If you use something like spiral duct, that stuff is really thin and flexes. I don't think spiral duct will transfer movement pressure to drywall. The PVC piping is also really stiff and non-flexible if you glue it together.

[Thomas Wilson]

Aaron, air velocity at the wall of the scroll is going to be quite high and will creat a pressure gradient pulling the Dynamat Xtreme off the wall. Have you noticed any pieces of the material in the filter downstream of the impeller?

[Aaron Inami]

Have you worked with Dynamat at all? It is extremely sticky and very difficult to pull off once it is applied. I do understand that there is a lot of air velocity, but the impeller is pulling air up and pushing it away to the sides (so in effect, the air pressure will push against the dynamat).

I haven't had any problem with pieces or dynamat being pulled off and ejected into the filter.