Clear Vue SP curve and what values for Bill Pentz calculator?

[Todd Brewer]

1. Is there a SP curve for the Clear Vue? I don't see it on the Clear Vue web site.

2. I have been "playing with" the Bill Pentz calculator. I am wondering what value I should use for CFM. If I enter 1000 then my SP is 12" or slightly above, if I enter 800 then my SP is around 10". I'm using the recommended 4000 FPM target air velocity. I have 6" PVC duct. Is 800 CFM possible at 10" SP? How do I know what the Clear Vue will pull at any given SP?

3. Bill Pentz has a chart for fan diameters and HP. But his chart does not list a fan that is equivalent to the Clear Vue fan. The Clear Vue fan is 15" and the motor is 5HP but Clear Vue does not specify the blade height. And to add more confusion, Bill's chart does not list a 15" fan. http://billpentz.com/woodworking/cyc...cfm#BlowerSize Am I splitting hairs?

4. Also, should I enter 45s in 1.5 R/D or 2.0 R/D or 2.5 R/D?

The more you know, the more you know you don't know.

Thanks,
Todd

[David Kumm]

Todd, welcome to the world of incomplete data. I have a clearvue curve I received privately but I'm not sure it reflects the more current backward inclined fan they use. The blade width is much less a factor than diameter and offset by differences in the housing configuration. I run an Oneida blower with a 15x5 BI fan and get 5000-6000 fpm on the 6" part of my main. Resistance goes up a lot as velocity increases and 4000 is the minimum- 5000 is better which converts to the 1000 cfm you want. I believe you will get the 1000 cfm but there are so many things you really can't calculate that it is just an educated guess. 6" does restrict the blower a lot and short radius ells don't help that. If you look at the tables at www.airhand.com or Cincinnati Fan you will find even higher numbers for different velocities. The CF tables show more resistance than most others but I don't know why. The 15" 5 hp system was developed to deliver 1500-1800 cfm with 8", 1200-1500 with 7" and 900-1200 with 6". Dave

[Todd Brewer]

Thanks Dave,

Best I can tell, my design is in the acceptable range. Bill's calculator is a nice tool to see how much the various pieces (45s, wyes, pipe length, etc) contribute to the overall SP. even if we can't determine the real values.

[Ole Anderson]

With all the good things they say about the CV cyclone, why isn't there a published fan curve (with cyclone and filter) for the current CV offerings? It is basic stuff needed to design your system. I don't get it. Maybe I am not looking in the right place. I know there is some unpublished info floating around but I would expect to see something on the Clear Vue Cyclones web site.

[Paul Stoops]

The Clearvue folks are great to deal with. Why don't you send them an email directly and request a copy of the fan curve you are interested in? If they have it available, which they probably do, I don't think they would have a problem sending it to you.

[Paul Wunder]

Ed Morgano had a fan curve published on the ClearVue website when he owned the company. I purchased my ClearVue from Ed a few years ago. Many months ago I was wandering about on the new owners website when I noticed that the fan curve was no longer available....so I emailed them and asked. They responded saying that they were going to re-test the cyclone and publish the results.

[Todd Brewer]

The Clearvue folks are great to deal with. Why don't you send them an email directly and request a copy of the fan curve you are interested in? If they have it available, which they probably do, I don't think they would have a problem sending it to you.

I'll send them an email. But I do wonder why I have to ask. It shoud be on thier web site. Kind of strange...

[David Kumm]

I agree that a curve should be posted but understand the danger as well if it is done fairly. Temperature, humidity, filter type and cleanliness all affect results. A 6" intake will look worse than a unit tested with an 8"- at least at low SP. If you know the fan type- radial, BI or BC, and diameter and width they will all pretty much perform the same under the same conditions. There won't be much difference among any manufacturers other than what is created by differences in cyclone resistance and filter type and area. The more important question that is never answered has to do with cyclone efficiency. An inefficient cyclone with low resistance might have a great curve compared to another with better separation. You can figure out the likely cfm from the Cincinnati Fan tables. It is impossible to figure out the separation that goes with it. Dave

[Chris Parks]

The thinking is that until someone can come up with a standard test or a standard to test against the result is dubious. Someone somewhere has to define a test that the industry can use to validate or debunk a whole lot of stuff surrounding DE but there is fat chance of that happening in my lifetime.

[Ole Anderson]

If they are working on it, fine. It just seems strange that CV seems to be the only big player in the DC game that doesn't publish their curve. Now comparing one curve to another is a separate issue. And not all fan impellers are created equal. One mfrs BI impeller is likely different from another, particularly when one is riveted steel, another plastic and another cast aluminum. What are the specs of the CV impeller, other than 15" diameter? Width, material, clearence to the housing, number of blades, angle, etc. Anyone have pics of the various impellers? I am no expert on DC impellers, but I do know that for water and sewage pump impellers, you don't look at one vendor's pump curve to see how another's will perform even if the impeller is the same general size and design. As I noted, if you are going to do a detailed duct design using Bill's (or another's) duct sizing program, you need the system flow vs pressure (or suction) at various air flows.

And coming up with a standard test isn't rocket science, although it gets much more difficult if you try to quantify particle removal efficiency at various sizes. For now, I would be happy with a system curve for clean air, new filters and 10 diameters of straight inlet pipe of a specified material with a bell inlet as an attempt for some level of laminar flow at the cyclone inlet. A butterfly damper could be used to induce losses at one inch WG pressure (suction) intervals.

[David Kumm]

I agree Ole that Clearvue needs to publish something. The Clearvue impellers are 15" or 16" with a 2.25" hub and 4.25" deep fins. The Oneida uses a 15x5" aluminum on their 5 hp unit. Although different, the fact that BI fans taper off at higher SP and are built to not overload a certain size motor by pulling more air at higher speeds, the working cfm won't vary enough that you can compare curves and know what is the fan and what is the cyclone and filter. Doesn't mean I'm defending Clearvue, I'm just sympathetic to anyone trying to compete with competitors specs that may all be fudged differently. Hope they come up with something credible. Dave

[Chris Parks]

As some know I am the Australian Clearvue distributor and anything I write here does not represent Clearvue, they are my own thoughts and no one else's.

[Chris Parks]

If they are working on it, fine. It just seems strange that CV seems to be the only big player in the DC game that doesn't publish their curve. Now comparing one curve to another is a separate issue. And not all fan impellers are created equal.

So by your own admission it is a dubious exercise at best? I am just playing the devil's advocate here BTW.

[Ole Anderson]

I am just saying that if you want to do anything other than a seat of the pants duct design, you need a fan curve.

[John Coloccia]

Is this for a commercial shop or a home shop? For a home shop, why are you going down a rabbit hole with calculators and fan curves? Stick the DC in a corner somewhere, run 6" pipe to everything as straight as you can, and get to work. I think this is one of those times where rule of thumb and collective experience obviate the need to reinvent the wheel. Unless you're running 100' of pipe all over a large shop, as a practical matter I don't think you need to go through all of this. Even if you do, what do you do when you find that a 5HP system with 6" pipe isn't enough? Install 3 phase? I guess you can step up to the Clearvue Max system, but that's incredible overkill.