Clearvue is releasing a new metal cyclone, the Pentz EF5

[Matt Mattingley]

Matt Bill has had ClearVue on his website for many years and ClearVue has said they are Pentz approved for just as long without ever posting a fan curve, I think that if they weren’t approved he would have stopped them. However you can always contact Bill and see what he has to say. Doesn’t take anything away from the cyclone though.

Peter, so true.

I am not in the market, but... I built mine for under $1000 with motor and fan & all stainless steal. I am just a hobbyist and I am trying to put together a fan curve. I figure any manufacturer would’ve hit this out of the gates.

[Peter Christensen]

I was going to build one but when the Ministeress of Finances gave approval I bought. Larry Frank has the scoop on making a fan curve chart because he did it for his own. There are a number of hot wire anemometers available for about $150 that will give you the airflow in the duct at the different static pressures.

[Joe Jensen]

Joe, I repeat you will never see a recommendation to run an 8" duct to a hobby machine. What you will see is a recommendation to run a 6" duct to a machine FROM an 8" main duct. I think this is standard practise for hobby workshops if using a 16" impeller. There has been some recommendation to use 7" with a 15" impeller some years ago but I don't think this has become widespread. As for your comments on the definition of a port I am equally confused with what you wrote, the port as I understand it is the exhaust extraction opening on the machine.

I will say again that a hobby shop should not have any 8" duct. Main branch or not. A 6" duct is about right to support two 5" ports. That means two ports that are no narrower than 5" all the way to the blade. Only my dual drum sander and Powermatic planer have no restriction inside the machine. All the rest have restrictions that make the true port like 3" or 4" effective diameter. Say you have a Sawstop ICS, it has effectively a 2.5" port inside under the blade shroud. And a 1.5" port on the blade guard. That 2.5 effective internal port has a cross sectional area of 4.9". The 1.5" blade guard port is 1.3" inside 1.5" outside for the hose. The 1.3" inside has a cross sectional area 1.33". Add the two together and you get a total area of 6.23 sq inches. That is the equivalent of a 2.82" Diameter port. Hook that up to 6" duct and it's going to perform poorly. Hook that 6" machine connection duct to an 8" main and your velocity will be super low. Bill Pentz's site has a great spreadsheet you can use to calculate all this stuff. A regular 2-5HP collector cannot generate enough suction pressure to move enough air through that SawStop lower and upper ports to keep dust suspended in an 8" duct, not even close. 8" ducts are for running multiple machines with 6" ports at the same time. Not for hobby shops with one person working.

[Josh Kocher]

"Not for hobby shops with one person working."

Maybe a bit of a broad statement?

A larger main supports less of a loss and more CFM. If you have the intake/airspeed/system to support it why wouldn't you?

[Bill Adamsen]

Jim the downside to the wyes coming out horizontally is the extra ninety degree elbow needed to point down adds an equivalent of 10 feet of straight pipe drag to the system. In this case not likely an issue because of the 5hp cyclone. It becomes a bigger issue on long runs or with marginal systems. With blast gates up along the top of the drops and remembering to open the blast gates once in a while should never be an issue. If the gates are at the bottom of the drop or at the machine then yes they can fill up and get plugged. The use of flex hose at the cyclone inlet amounts to more drag than having the horizontal wyes. Dust collection is never easy is it.

Did you include the extra 45° required for the down drop to go vertical? 45°s typically impart a little more than half the friction of a 90°. But I understand the point. And you make an excellent point about the location of the gate. The worst part is that – depending on the material chosen and approach to assembly (adhesive) – mistakes can be very time-consuming to repair.

[Joe Jensen]

"Not for hobby shops with one person working."

Maybe a bit of a broad statement?

A larger main supports less of a loss and more CFM. If you have the intake/airspeed/system to support it why wouldn't you?

Dust collection is confusing and the manufacturers of collectors market on CFM which is easy but way too simplistic.

First lets start with dust collectors. Collectors generate suction (negative pressure) measured in inches of water (W.G.), and airflow measured in cubic feet per minute (CFM). The max suction a collector can generate is with the inlet plugged and zero airflow. That would be something like 15" W.G. at zero CFM. Then you can measure max CFM with no duct or ports attached, this would be called zero static pressure. This would be something like 1600 CFM at zero W.G. Then several other points are measured and a curve is plotted, this is a fan curve for each collector that plots the CFM measured with different port sizes.

Next there are the things that add resistance to airflow.

1. The resistance of the air flowing in the duct. That is called static pressure and measured in inches W.G. The faster the air flows the more the resistance. If the air flows twice as fast the resistance is four times higher. For a given CFM of air moving in a duct, the larger the duct diameter the slower the air will flow. If you are moving 350 CFM of air through a 4" duct, it will be flowing at just over 4,000 feet per minute. Now connect that 4" duct to a 6" duct and you will still be moving 350 CFM but because the 6" duct is a lot larger, the air will be moving slower. The 6" duct has 2.25 times more cross sectional area than the 4" duct. So the air will flow 2.25 times slower in the 6" duct. That means the 4,000 feet per minute will be 1,778 feet per minute in the 6" duct.
2. The port at the machine. The study in engineering of how all this works is called fluid dynamics. When you study fluid dynamics you will learn that the smallest opening in the path of airflow is the primary factor in how much resistance to airflow there is. It's easier to think of this with a water example. For example, say I have a residentail water supply with a hose bib on it and I open the bib half way and measure the gallons of water I can collect in a minute. That would be like measuring the CFM (gallons per minute) through a hose bib (port) at a given water pressure. Now say I keep the water pressure the same, but I put a much larger pipe on the water supply. Unless the initial supply pipe was wildly undersized the gallons per minute will be the same. If I want to fill the bucket faster there are two things I can do, increase the water pressure at the supply or open the hose bib to make a larger opening. Now back to Fluid Dynamics. If you want to double the flow through a given port size you need four times the pressure. So if I want to double the gallons per minute I would need to go from a water pressure from the city of say 70 pounds to 280 pounds. Or I could open the port up a bit more. Now back to our dust collection. We either need to quadruple the suction at the port or enlarge the port of we want higher CFM.
3. The cyclone adds some resistance. Bill Pentz spreadsheet shows a typical cyclone at 3.5". I use a pleated filter so say 0.5" for the filter, and 0.15" for the muffler.
4. Duct - the higher the velocity of air flowing in the duct, the more resistance or static pressure.
5. Bill Pentz also show misc overhead resistance from things like leakage and dirty filters.

You can calculate with pretty good accuracy how much CFM you will pull through a machine port with Bill Pentz's spreadsheet. In there you select your cyclone, filter, muffler, etc. Also duct sizes, elbows, amount of flex, and most importantly the actual port diameter at the point of collection. You then load the target CFM for that machine. It will then tell you the total resistance for that branch as well as the CFM etc and the ideal duct size. Great tool but you need to understand the principles to make good use of it. Once you get the total resistance you look at the fan curve and see how much CFM your collector can deliver at that resistance. Another way to think of this is if you take the max pressure (at zero flow) from the fan curve, and you subtract the resistance from the spreadsheet you will get a net pressure at the port. If we had a collector that could generate 15" WG of pressure at 0 CFM, and the branch resistance total is 11.74" WG, the net pressure at the port would be 3.26" WG. Now if you want to double the CFM through that port you would need to quadruple the pressure at the port to 14". That means you would Need a collector that could generate 14" more pressure than your current one. Current was 15" and your need now one that generates 29", super unlikely.

I posted PDFs of a deeper paper on this in the sticky on dust collection.

[Peter Christensen]

Joe everything you say is true but you make the assumption that we are going to accept the little ports manufacturers put in their machines. If we are willing to open the ports up for maximum airflow then the need for bigger ducts that the DC can support is valid. I will have no problem putting another port in my SawStop (you like to cite it as an example) cabinet and since I don't have their overarm DC guard I'll be making one with at least a 4" duct so it would need a bigger main line. Since I also use both table saw and jointer together at times I can take advantage of an 8" duct from my CV-Max. You haven't mentioned wood lathes but you know full well they are the one machine that cries for maximum airflow so an 8" line to it with a bell mouth hood is a given. Now should someone want to make a small sanding station with a downdraft or backdraft table to use in addition to their vacuum cleaner connected RO sander, they will also benefit from the big piping. There is nothing preventing us "big pipers" from having an extra blast gate open to act as a bit of air scrubber so the DC maintains good airflow and the pipe stays clear.

If we accept the dust ports sized from the recommendations from when life was good and nobody locked their house and cars, then big pipes are indeed useless. Then again we can accept the same lung problems with that fine dust those under ported machines won't let us collect. I'm in agreement with what you say can be had from a DC but not with accepting the dinky ports on the machines that you appear to want to accept. Your choice is yours and not mine. We can agree to disagree.

[Matt Mattingley]

Peter you don’t really need a larger pipes to move more CFM. I actually had to use a bigger pipe to slow down my feet per minute just measure it.

If you have enough pressure you might be able to pull the required amount CFM through a 6-7” pipe. One thing I know is I would over amp my motor if I ran 8 inch and I opened to 6 inch ports. My max intake is 40 in.². I could transition to a 7 inch main. But with a 6 inch port open off my 6 inch mean I am pulling almost 20 A on my 22 amp motor.

I’ll let you do the calculations. 5” Port, 5” flex stepped up to 10 1/4 inch ID and I was measuring about 2100 ft./m

[Peter Christensen]

Three phase motor controlled by a VFD which can be set in the parameters to limit amperage during startup and max drawn at any time. No worries about overheating the motor or popping a breaker.

[Matt Mattingley]

Three phase motor controlled by a VFD which can be set in the parameters to limit amperage during startup and max drawn at any time. No worries about overheating the motor or popping a breaker.

I wasn’t talking about at start up. At start up I had about 110 amp for two seconds. I have never blown or popped the 30 amp breaker. Once a gets up to speed with a 6 inch port open I’m pulling 20 A.

When this motor is shot, I will definitely be using a three phase motor and VFD. But the other motor has been running for five years.

[Peter Christensen]

Reread what I said. To expand. The VFD can be set to limit the maximum amperage draw at anytime. It will never allow any more amperage to the motor than the amount you programmed. If you set it to 19 amps, that is all the motor will ever get. Set it to 21 amps and that is the maximum.

And for what it is worth a CV-Max is designed to use 8” main lines and have two 6” ports open at the same time.

[Matt Mattingley]

Reread what I said. To expand. The VFD can be set to limit the maximum amperage draw at anytime. It will never allow any more amperage to the motor than the amount you programmed. If you set it to 19 amps, that is all the motor will ever get. Set it to 21 amps and that is the maximum.

And for what it is worth a CV-Max is designed to use 8” main lines and have two 6” ports open at the same time.

That is totally understandable. The intake port on the CV is 4 x 10. That is 40 in.². This steps up to 8 inch or 50 in.². So there is a restriction in airspeed in the main compared to the intake. The last time I tested a CV it only would pull 14 inches of water column right at the intake with dust bin attached. The CV is only using a 16 inch impeller. I also checked the amperage with no duck work bin attached . It was only pulling 16 A.

So I just checked the exhaust from the blower, it is 5.625×7 = 40 in.² too.

So 40 in.² in and 40 in.² out of the cyclone. You could put a 10-12 inch main trunk if you really wanted to. It would never over amp the motor if you had 5=>6” blast gates open.

[Joe Jensen]

Three phase motor controlled by a VFD which can be set in the parameters to limit amperage during startup and max drawn at any time. No worries about overheating the motor or popping a breaker.

The Oneida smart collector solution

[Josh Kocher]

Joe.

Thanks for the detailed post... but you didn't answer my question.

A larger main supports less of a loss and more CFM. If you have the intake/airspeed/system to support it why wouldn't you?

[David Kumm]

Go to the Cincinnati fans tables and download them. You will see how BC vs radial blades impact cfm per amp at pressure increments of 1". You will see how the blade configuration and diameter impact cfm at pressure. There is also enough information to see how impeller housing can affect cfm as well as inlet diameter. The tables explain a lot. What they won't add though is that each cyclone is designed for a certain range of cfm or velocity into the inlet. A CV with an 18" diameter is sized for a cfm working range of 1200-1400 cfm and as cfm goes up, separation efficiency goes down. I don't know the numbers but the two filters used have a maximum cfm rating of 1200 so while you can juice the unit somewhat, the cyclone and filters will still be the limiting factor.

As an example, an 18x4.375" BC impeller needs a 7.5 hp motor but will pull 1086 cfm @18" sp needing 5.2 hp. A 16.5x4.375 BC impeller will pull 1164 cfm @14: sp needing 4.29 hp. A 15.5x5" BC impeller pulls 1189@12" sp needing 3.73 hp.

A 15.5x5" radial impeller pulls 1491 cfm@ 14" sp using 5.5hp and 955 cfm@ 16" sp using 4 hp. The same size BC impeller uses less hp per cfm but provides half the cfm ( 709 vs 1491 ) @ 14" sp.

Looking and comparing the info on the tables gives you a clue as to the cfm range an impeller is capable of. You then need to do some rough math to determine the pressure range you will operate in. I figure 8"-14" is my range- long runs, 25 gates and impeller located remote from the cyclone. I wanted a max cfm of 2000+ for my large old machines but was limited to 8" and 7" mains. That limitation mandated my impeller options. Had I read the tables early on I would have saved a couple of impeller swaps. Dave