pictures

[RCOX]

Vodkaman: going to Lowes and get a couple of things, then back to playing. I will keep trying different heights of baffle and angles of baffle to inlet. Once I get that where I am happy, I already have a wye to replace the accumulator. Should be done later today. Then as money allows, I will be changing plumbing to 6" for most of my main. I will be converting to 1 main instead of 2, which I think will also improve my setup considerately.

[RCOX]

Finally found the sweet spot for my baffle. Very little dust collecting on the bottom of the baffle, and inside the separator the dust swirl is almost horizontal. This seems to leave the least amount of dust clinging to the underside of the baffle.

R&R the accumulator with a 6" hvac wye. A little improvement but would not have been worth the trouble if I did not plan to switch the main trunk to a 6" line also. This is something we discussed and you don't know the outcome until you do it. Now I know. I tried opening both lines with the thought that a 6" line (from the wye through the separator to the dc) being 2.25 times larger than a 4" line should be able to pull that much with a little to spare. WRONG. There was at least a 30% loss of suction on the "working" line when I opened the gate on the second line. This is not really an obstacle as I am the only person using the system, just stating my observations. I hope it will be worth my effort to switch out the 4" mains that I have now and go with 6". This will be a project for the future.

The other thing I noticed. When I opened a second gate there was a mild hammering sound coming from the impeller area. With only 1 gate open this did not happen. It only happened with 2 gates open. I did not try a 3rd gate to see what happened, just occured to me as I typed this. Does anyone have a thought on what this could be? I do not recall it doing this when I had the accumulator in place but it would do it if I ran the system with the separator disconnected from the rest of the system.

I also started taping seams on my ductwork. Trying to stop as many airleaks as possible. None were serious but several small ones add up to the same as a big one.

Now it is time to start making some saw dust and really test these changes.

Thoughts or questions, let me know.

[RCOX]

No, I haven't forgotten it. I have not decided how to raise it and still be able to reach the filter flappers. Be nice if my Powermatic had flapper motors like the JDS portable cyclones do. May not be an issue with the separator but have really had to use them when using the drum sander. Was also curious if using a short run of flex would increase or decrease restriction. It would make it easier to smooth out the bends with the flex but would I just be trading 1 issue for another. Right now, I have a couple of projects and a small honeydo list that needs to get done. The projects will give a real world test of my setup instead of just sucking up a drum of dust, dumping it , make some changes and suck it up again.

Interested on input on the flex idea. I can make do with about 5' and could really smooth out the turns.

[retired2]

No, I haven't forgotten it. I have not decided how to raise it and still be able to reach the filter flappers. Be nice if my Powermatic had flapper motors like the JDS portable cyclones do. May not be an issue with the separator but have really had to use them when using the drum sander. Was also curious if using a short run of flex would increase or decrease restriction. It would make it easier to smooth out the bends with the flex but would I just be trading 1 issue for another. Right now, I have a couple of projects and a small honeydo list that needs to get done. The projects will give a real world test of my setup instead of just sucking up a drum of dust, dumping it , make some changes and suck it up again.

Interested on input on the flex idea. I can make do with about 5' and could really smooth out the turns.

Rcox, published friction losses for flex hose states that it is 3 to 4 times greater than smooth pipe.  So, to put that in perspective, if you have 5 foot of flex hose, it is the equivlent of 15 or 20 feet of smooth pipe. 

I have not found any data specific to bends, but I would expect the same rule to apply.  For example, a 6" 1.5D 90 degree bend is the equivalent of 12 feet of straight pipe.  That same bend using flex hose would be the equivalent of 36' to 48' of straight pipe.

And remember if you are considering 1D bends, all the numbers in the above examples double again.  So, if you are unable to find larger radius ells locally, just use two 90 degree 1D bends.  Rotate the segments to make each one a 45 degree bend and then connect them together.  That gives you a large radius 90 degree bend for only a small additional investment.

Hope this helps.  Regards.

[retired2]

Rcox, published friction losses for flex hose states that it is 3 to 4 times greater than smooth pipe.  So, to put that in perspective, if you have 5 foot of flex hose, it is the equivlent of 15 or 20 feet of smooth pipe. 




Hope this helps.  Regards.

Retired, you don't say if thats the generic black plastic inexpensive DC flex, or smooth interior wall flex, I'm guessing that those losses are from the inexpensive DC flex.

Chuck, none of the documents where I found information regarding line losses for flex hose make any distinction between type of hose.  I don't own any "generic inexpensive" black hose, so I don't know how it is different in construction or feel from the clear hose I own. 

My clear hose was purchased from three sources: Wynn Environmental, Oneida Air, and Rockler.  They are all constructed the same way except for the gauge of the plastic, the gauge of the wire, and the direction of rotation of the helix.  I would not say any of them are smooth.  Yes, the plastic is smooth to the touch, but they all have an inherent rib that is produced by the wire helix.  My understanding is that it is this rib that produces the turbulance and resulting line losses.

The length of gray hose that came with my Delta DC is the closest thing I've seen to a flat interior, but again I wouldn't call it smooth because it also has a spiraling groove on about a 1/2" pitch.  I've tried stretching my clear hose using weights on a 90 degree day, but it has a memory, and if left unrestrained it will return to nearly its original length. 

I suspect the line loss differences between all these hose types is pretty similar, because none of them have a smooth flat inside wall. 

[RCOX]

Chuck: The pictures don't really show it too well but where my dc sits I would have to move my miter saw table and my separator every time to get a step stool to my dc. I am still looking at getting more adjustable ells and rounding out the 90s that I have now. Just a matter of time. Still a work in progress.

Retired2: the black cheap flex that Chuck is referring to makes the clear premium flex smooth as a babies bottom. I have some of both and there is a very noticeable difference. To give you a comparison the black flex I bought was about $23.00 for 20' while the clear was about $30.00 for 10'. I will admit you get what you pay for with this stuff.

[retired2]

Retired2: the black cheap flex that Chuck is referring to makes the clear premium flex smooth as a babies bottom. I have some of both and there is a very noticeable difference. To give you a comparison the black flex I bought was about $23.00 for 20' while the clear was about $30.00 for 10'. I will admit you get what you pay for with this stuff.

Glad I never bought any of the cheap black stuff!! 

Here's a revealing quote from Wynn Environmental's web-site regarding their clear flex hose.  "All of our hose is what the industry refers to as "Smooth Bore Flexible Hose".  We are not big fans of this term, because it is misleading,.."

[Vodkaman]

R&R the accumulator with a 6" hvac wye. A little improvement but would not have been worth the trouble if I did not plan to switch the main trunk to a 6" line also. This is something we discussed and you don't know the outcome until you do it. Now I know. I tried opening both lines with the thought that a 6" line (from the wye through the separator to the dc) being 2.25 times larger than a 4" line should be able to pull that much with a little to spare. WRONG. There was at least a 30% loss of suction on the "working" line when I opened the gate on the second line. This is not really an obstacle as I am the only person using the system, just stating my observations. I hope it will be worth my effort to switch out the 4" mains that I have now and go with 6". This will be a project for the future.

The other thing I noticed. When I opened a second gate there was a mild hammering sound coming from the impeller area. With only 1 gate open this did not happen. It only happened with 2 gates open. I did not try a 3rd gate to see what happened, just occured to me as I typed this. Does anyone have a thought on what this could be? I do not recall it doing this when I had the accumulator in place but it would do it if I ran the system with the separator disconnected from the rest of the system.

I also started taping seams on my ductwork. Trying to stop as many airleaks as possible. None were serious but several small ones add up to the same as a big one.

Now it is time to start making some saw dust and really test these changes.

Thoughts or questions, let me know.

I am sorry you did not get the improvement in performance that you were looking for after replacing the accumulator with a Y, but you did get an improvement. Maximizing the efficiency of your system is going to be lots of small improvements, like straightening out runs and removing elbows, sealing leaks etc. The fact that you actually noticed a change is significant, some improvements may only register on instrumentation, but the cumulative improvement is there.

There was always going to be a large drop when you open the second line, I don?t see how this can be avoided.

The vibration problem is interesting. Is that happening with two gates opened on the same line or one gate on each line.

Dave

[RCOX]

Vodkaman: It happens with 1 gate open on each line. I did not notice it with 2 gates on the same line. Don't know if it has to do with air volume or what. It may have done it before but I never noticed it. I just thought it odd that when I opened the second line that I noticed this sound. The only difference I can explain is that the extra volume of air with 2 lines open. The problem with this thought is that this dc is designed for more air than what I have allowed it. More experiments in the works for me.

[Vodkaman]

What ever it is, it is not good. This vibration could reduce the life of the bearings over time.

I am thinking resonant frequency, like the vibration you get in some old cars at certain frequencies. What happens if you open a third gate or partially close one of the two open gates?

If it is resonant frequency and the above two tests stop the vibration, probably the next improvement that you make to the system will clear it. On a positive note, any changes you make, you will be able to hear the difference ;D

Just theorizing here.

Dave

[retired2]

Vodkaman: It happens with 1 gate open on each line. I did not notice it with 2 gates on the same line. Don't know if it has to do with air volume or what. It may have done it before but I never noticed it. I just thought it odd that when I opened the second line that I noticed this sound. The only difference I can explain is that the extra volume of air with 2 lines open. The problem with this thought is that this dc is designed for more air than what I have allowed it. More experiments in the works for me.

Rcox,

I just found an engineering data document on line from a prominent fan/blower manufacturer.  There are a number of duct installation guidelines that are useful.  One in particular may have significant bearing on your problem, particularly your vibration.

The guideline states that an elbow too close to the fan inlet reduces the fan's air performance due to turbulance.  If the pipe system has no turning vanes, there should be a minimum of straight pipe equal to three wheel diameters between the fan inlet and the elbow. 

When I read this guideline I immediately thought about your first photo with what looks like a short radius elbow attached directly to the fan inlet, or if not, very close to it.

[RCOX]

Vodkaman and Retired2: I found the "noise problem" today. The duct from the impeller to the filter/catch bags was vibrating with the extra airflow. I placed a clamp across the width of said duct and it stopped. One problem solved.

I also found that my separator works better with the baffle about 1" below the inlet pipe.To do this, I had to move the baffle to 6 3/4" below the top, then I re-installed the outlet tube so it was 5" above the baffle. Noticeable improvement. Then I discovered that if I opened another gate, as was suggested, that suction reduced severely. My question, was it cfm that I lost or just velocity? With a second gate open, on the other line, I was still able to pick up the chips that I used as a test medium but at a lot slower pace. With only the 1 line open, the transfer was a lot faster and it appeared to clean the fine dust from the flex hose a lot better. All testing has been done through the following, 10' of 4" flex, blast gate, 25' pvc into the 6" wye then the separator and finally the dc.

Now, here is another observation/question. My inlet to the separator is a 4"X10"X6" end register, torpedo style. As I stated in an earlier post, placement of the baffle in relation to the inlet has a great impact on what the dust does in the separator.  I thought that if you placed more of the wide part of the baffle in front of the inlet that you should get better separation. Wrong. It appears that if the end portion of the slot is too far forward, you get more up swirl and more chips re-entering the airstream. When you place the end of the slot almost even with the beginning of the entry you get more suction and better separation, the chips/dust also has a flatter swirl in the separator. With the brute trash can I am using, you get a little flexing/collapsing of the side of the can opposite the entry point when you place the baffle with more than half of it in front of the entry. With the end of the slot even with the leading edge of the entry I will collapse the can at least a third of the diameter. In this position the baffle actually prevents the dust from rising into the incoming airstream. My question, is this normal, how it was originally designed to work or am I just trying to over analyze this whole procedure?

Enough of my rambling tonight. My brain hurts, I am going to bed.

[retired2]

Vodkaman and Retired2: I found the "noise problem" today. The duct from the impeller to the filter/catch bags was vibrating with the extra airflow. I placed a clamp across the width of said duct and it stopped. One problem solved.

I also found that my separator works better with the baffle about 1" below the inlet pipe.To do this, I had to move the baffle to 6 3/4" below the top, then I re-installed the outlet tube so it was 5" above the baffle. Noticeable improvement. Then I discovered that if I opened another gate, as was suggested, that suction reduced severely. My question, was it cfm that I lost or just velocity? With a second gate open, on the other line, I was still able to pick up the chips that I used as a test medium but at a lot slower pace. With only the 1 line open, the transfer was a lot faster and it appeared to clean the fine dust from the flex hose a lot better. All testing has been done through the following, 10' of 4" flex, blast gate, 25' pvc into the 6" wye then the separator and finally the dc.

Now, here is another observation/question. My inlet to the separator is a 4"X10"X6" end register, torpedo style. As I stated in an earlier post, placement of the baffle in relation to the inlet has a great impact on what the dust does in the separator.  I thought that if you placed more of the wide part of the baffle in front of the inlet that you should get better separation. Wrong. It appears that if the end portion of the slot is too far forward, you get more up swirl and more chips re-entering the airstream. When you place the end of the slot almost even with the beginning of the entry you get more suction and better separation, the chips/dust also has a flatter swirl in the separator. With the brute trash can I am using, you get a little flexing/collapsing of the side of the can opposite the entry point when you place the baffle with more than half of it in front of the entry. With the end of the slot even with the leading edge of the entry I will collapse the can at least a third of the diameter. In this position the baffle actually prevents the dust from rising into the incoming airstream. My question, is this normal, how it was originally designed to work or am I just trying to over analyze this whole procedure?

Enough of my rambling tonight. My brain hurts, I am going to bed.

Rcox,

With regard to cfm vs fpm, they are tied together mathmatically such that for any given size pipe a decrease in one results in a decrease in the other.  Likewise an increase in one results in an increase in the other.  Now if your comparisonis before and after a change in pipe sizes, that's a different story.

With regards to the baffle slot and the outlet pipe, there seem to be two well proven relationships.  The recommended slot position is spelled out in numerous posts.  The easiest to find is pitbull's "6" inlet/outlet how to" thread.  The most recommended outlet pipe position is to set it about 1/2 the pipe diameter below the separator top.  After taking a closer look at your inlet design, I can see why you would have a problem with the outlet recommendation.

After paying more attention to your inlet design, I really think it may be hurting the performance of your separator.  Your aspect ratio is just the opposite of what I think it should be for a rectangular inlet.  Yours is short and wide rather than tall and narrow.  That could be causing several problems.  There could be short-circuiting, i.e. waste stream getting to the outlet without being spun.  It is also likely to be causing more impingement turbulance as described in pitbull's test video, and the short body is affecting the desired position of the outlet nozzle.  I think the Brute trash can is better suited for a true top-hat design rather than a tangential internal separator.

[RCOX]

I spent about 3 hours yesterday playing with this. I would adjust the baffle up/down, adjust the outlet up/down I finally got what I perceived to be the desired action i.e., separation that I can be happy with and very minimal, if any, bypass through the outlet to the dc. To get the best separation I settled on the 1" below the inlet that I described last night. To achieve the most suction possible with my current setup I "maybe" had to compromise from the original design by not having the outlet exactly 1/2 the diameter through the top. It is only about 1 3/4" through instead of 3" but I was not able to tell that it made that much noticeable difference. Believe me, I tried all combinations. As far as the orientation of my inlet, if you look back at the last picture, I don't see how having a taller transition would be better or feasable. The way the inlet I used tapers inward from the 6"round to the 4"hX10"l discharge appears to give a smooth flow of air and dust that produces a relatively good cyclonic action. The orientation of where I place the wide portion of the baffle in relation to the inlet has more effect on action than anything else I have tried. Also as Chuck stated earlier, or more so how I interpeted what he said, the distance from the outlet pipe to the baffle has more to do with suction than how much the outlet sticks through the top. The way I finished with mine gives very good suction with no perceptable short circuiting. It is time for me to actually start using this thing and give it a real test and quit trying to re-invent a great design/idea. Time and use will determine what other changes I need to make, if any. Phil, I want to thank you for sharing your idea with us all.

Raymond

[RCOX]

Phil/Chuck: If I can make an accurate "written" picture, I hope you can give me an answer. Using the brute trash can, when I place the widest part of the baffle more than 50% in front of the centerline of the inlet I get a lot more upswirl of chips in the can (as viewed through the window) and the can only collapses/deflects about 1 1/2". When I place the centerline of the baffle 25% before the centerline of the inlet I get a flatter swirl with less chips rising through the slot back into the incoming airstream but the can collapses/deflects 3-4" inward. My question is, is this normal, have you witnessed similiar and what is your opinion on what this is doing to the suction? Is the extra deflection indicating better suction or is it wasting usable suction? I only noticed this a couple of days ago and haven't used it anymore yet, to try and determine what is going on. I do have a metal 30 gallon trash can I am thinking of setting up to give more rigidity. The complete separator will work on the other can after I cut the rabbit an 1/8th" wider. Then I will need to put in the inlet and see what happens.

Thanks for your suggestions.

Raymond