No pictures from me tonight. Your site says 1920 kb max, yet it will not take pictures even after I downsize them to 134 kb, what gives?
Adding those sharp 90-degree elbows can really drop CFM substantially. I'd try to figure out ways to get rid of the elbows.
Phil: with the limited real estate where the separator sits I couldn't think of any other way to do this unless I use some flex and curve it up and around a little more. Suggestions?
Chuck: the outlet is about 3" down from the top, 1/2 the diameter as suggested and it is also about 3 1/2" up from the baffle. This picture doesn't show that too well. If you think it should be more, what is your suggestion? I am open to all.
I was just wondering if you thought the accumulator might also be part of the problem or not. With the lexan front I am able to see a lot of swirling around and was not sure if that indicated a problem or just natural air pattern. I still really like the design and only had to buy a couple of items, the rest I had laying around the shop.
Another thought on your suggestion. Would it be better, where I have the 90 degree ells to replace them with 2-45 degree ells with maybe a short 6"straight run between each 45? I think I will have enough room to do this if you think it will help. That is what I have done on the pvc main runs in my original setup.
Quote from: RCOX on July 20, 2011, 07:53:23 AM
Phil: with the limited real estate where the separator sits I couldn't think of any other way to do this unless I use some flex and curve it up and around a little more. Suggestions?
Many users have removed the blower from the base of their DC and turned/mounted it to the wall above the separator. Then you have a straight shot from separator to blower inlet. You can then mount the filter to the side of the blower and avoid another elbow.
Quote from: RCOX on July 20, 2011, 08:34:26 AM
Another thought on your suggestion. Would it be better, where I have the 90 degree ells to replace them with 2-45 degree ells with maybe a short 6"straight run between each 45? I think I will have enough room to do this if you think it will help. That is what I have done on the pvc main runs in my original setup.
That is better than what you have now, but mounting the blower higher than the separator would be even better.
Some people don't want to start disassembling their units, which I understand.
Phil: you are correct, I really don't want to tear my dc apart at this time. Raising it higher sounds like a better idea. Chuck also brought this up and I have 12 foot ceilings so have plenty of room.
Chuck: I do not take this as criticisim at all. I asked for opinions and that is how I look at this. As far as the tweeking goes, I told my wife that I probably would never be completely satisfied with my setup so would have to keep working on it. Best way I know to get new stuff. She understands that, because her sewing room is also a work in progress.
Thanks to both for your input, it has been helpful. Now back to the shop and she what I can make of this.
Quote from: RCOX on July 20, 2011, 08:34:26 AM
Another thought on your suggestion. Would it be better, where I have the 90 degree ells to replace them with 2-45 degree ells with maybe a short 6"straight run between each 45? I think I will have enough room to do this if you think it will help. That is what I have done on the pvc main runs in my original setup.
It appears you have four 6" short radius (1xD) ells between the accumulator and the DC inlet. Short radius ells have considerably more friction loss than a 1.5xD ell. A 6" 1.5xD ell has losses equivalent to12 feet of straight pipe. For further comparison, a 2.5xD ell is the equivlent of only 6 feet of straight pipe. No way of knowing what the friction losses are for your accumulator, but I suspect it is the equivalent of at least another 90 degree ell.
Above the accumulator you have two short radius 45 degree ells that appear to be 4" in diameter. Two 45 degree ells produce the same friction loss as a single 90 degree ell, that is IF they have the same bend radii. So, if these 45 degree ells are 4" in diameter and 1xD bend radius, they add the equivlent of another 6 feet of straight pipe.
If we use the losses for 1.5xD ells, your current configuration is roughly the equivalent of roughly 66 feet of straight pipe. I can't confirm the data, but my notes show the loss for a 1xD 6" ell as the equivalent of 24 feet of straight pipe. If that is correct, your losses from just above the accumulator to the DC are equivalent to more than 130 feet of straight pipe.
So, one way to reduce your losses is use all long radii bends. I have a 5" system and I use 1.75xD ells from Oneida Air.
Chuck: I had the setup you describe just before I changed to this one, with the only difference being the separator. I was using the Rockler design, entry and outlet on the outer edge of the lid and a 90 degree ell in opposing directions on the inside. Each one worked great but when I would change from 1 line to the other, the 1st can would empty into the dc. If you think using the Thien baffle design would prevent this it is worth a try. You are correct in the 1900 cfm and plastic trash cans. When I was using the other setup I could collapse the can that was shut off. I had to leave a blast gate partially open to prevent this and I think that is why the opposite can would empty, there being enough air flow to scrub the can. Do you this would happen with the Thien baffle design or would the baffle be enough to prevent the scrubbing action? I could use the original Thien design, top entry and exit, connected with a very short run of 4" flex to the entry point and a moderately longer run from the separator to the dc 3 way wye you referenced and eliminate a lot of hard 90's in the process. This would take care of the concerns expressed by yourself, Phil and Retired2. Any thoughts about the possible scrubbing vs eliminating wyes and the ensuing loss of suction will be most appreciated.
Retired2: I appreciate your input. I knew there was a difference in suction loss with different ells but had never calculated it out. I used some 45 degree ells with a short section of pipe between trying to reduce loss. When you actually put numbers to it, it really changes the whole picture. I think Chuck is on to something with his idea of trying 2 separators. I already have nearly everything I need to change over, I would only need to build the baffle setup for the cans I already have. Will wait on the answer back from Chuck and give it a try. Thanks for the eye opener. 160 ft of pipe equivilent, just from above the accumulator to the dc. Never would have guessed. Thanks
Quote from: RCOX on July 20, 2011, 03:38:16 PM
Retired2: I appreciate your input. I knew there was a difference in suction loss with different ells but had never calculated it out. I used some 45 degree ells with a short section of pipe between trying to reduce loss. When you actually put numbers to it, it really changes the whole picture. I think Chuck is on to something with his idea of trying 2 separators. I already have nearly everything I need to change over, I would only need to build the baffle setup for the cans I already have. Will wait on the answer back from Chuck and give it a try. Thanks for the eye opener. 160 ft of pipe equivilent, just from above the accumulator to the dc. Never would have guessed. Thanks
I don't know of anyone who has done accurate measurements for the losses associated with Phil's separator, but I think Bill Pentz claims that "trash can" style separators can use 4+ inches of static pressure. I don't know if that number is in the ball park for a Thien separator or not, but if so, for a 6" pipe at 4000fpm, that's another equivalent 100 ft of straight pipe.
Chuck: you are correct about my shop being a one man show. My shop is 14 x 48, with most of the action in the front. My dc is centrally located with 1 line going to the front to a table saw, a Jet 22/44 oscillating drum sander and a piece of flex hose for whatever. The 2nd line goes to the rear to a miter saw cabinet (primary tool on that line), a 6" jointer, Rigid lunch box plane, band saw, horizontal belt sander and a router table. I also have a 2" line coming off of the 2nd main that goes to the front, to an over blade hood on my table saw. The miter saw cabinet stays connected as does the table saw and drum sander, all other tools are on mobile bases and gets moved around as needed. From what you are saying, I could build 2 separators and leave the gates open to the miter saw cabinet on 1 line and leave the gate for the table saw open on the other line until I needed another tool at which time I could close the respective gate and open 1 for the other tool. I also have 2 metal 30 gallon trash cans I can use for this in place of the rubbermaid brutes that I now have. Thank you for your help.
Retired2: I hate to say it but if we keep going my dc will be blowing instead of sucking. I do know that I do not have access to the equipment needed or the knowledge required to do this type of testing. All of my assumptions have been made of the redneck type testing, putting my hand across an opening/connection and having my wife open and close blast gates until I make up my mind what I think the problem may be. I am fortunate to have a wife that will help me indulge my curiosity.
Chuck, the more I think about it the more I like your idea of using 2 separators. It will be next week before I can start on this do-over but am going to give it a try. I am off work during the week and will just to see what my evenings bring before getting to this but think you may have hit on a solution. Thanks to all for your input and suggestions. Will post the results in a week or so.
Quote from: retired2 on July 20, 2011, 06:04:20 PM
I don't know of anyone who has done accurate measurements for the losses associated with Phil's separator, but I think Bill Pentz claims that "trash can" style separators can use 4+ inches of static pressure. I don't know if that number is in the ball park for a Thien separator or not, but if so, for a 6" pipe at 4000fpm, that's another equivalent 100 ft of straight pipe.
It is difficult to make generalizations here because the implementations vary by a wide degree. Some use a side inlet, some use top inlet. The diameter of the drum tends to vary from one implementation to another. And some units are just plain better built than others.
One of my units with a side-inlet can easily best a cyclone in terms of frictional losses. Basically, shorter path = less friction.
You mentioned turbulence in the accumulator. This is obviously causing some losses as turbulence is never a good thing. It may be prudent to fix this first, as you do not know to what extent the accumulator losses are affecting things.
One step at a time. If you fix everything at once, you will never find out what worked and we (the viewers) learn nothing from your experiences ;D
Dave
Phil: So many choices and with my limited knowledge of suction loss due to sharp radius turns, size of pipe restrictions etc. is enough to boggle my mind. I went with the 6" pipe size through the separator because it is 2.28 times larger area wise than 4" and I wanted to not have to completely replumb my shop. That would probably be the smart thing to do but at this time I am not in a position to do so. I work in maintenance and actually Vodkaman's approach is the way I do all my trouble shooting to repair equipment. There has been a lot of good info put out there and I will admit, I was looking for the easy way out. Give me the answer don't make me figure it out myself. I have been the most concerned about the accumulator knowing I should start by replacing it. Chuck had a very good thought about going with 2 separators but I have been down that path except, with the Rockler type setup, not your design. I think I will probably put my experience in troubleshooting to work and see where it leads. Maybe in the end I will have all new plumbing throughout maybe not, but I will have gained a lot of knowledge in dust control (good or bad).
Vodkaman: thanks for the smack up side the head. Will post results as they progress.
Quote from: RCOX on July 21, 2011, 04:29:49 PM
Phil: So many choices and with my limited knowledge of suction loss due to sharp radius turns, size of pipe restrictions etc. is enough to boggle my mind. I went with the 6" pipe size through the separator because it is 2.28 times larger area wise than 4" and I wanted to not have to completely replumb my shop. That would probably be the smart thing to do but at this time I am not in a position to do so. I work in maintenance and actually Vodkaman's approach is the way I do all my trouble shooting to repair equipment. There has been a lot of good info put out there and I will admit, I was looking for the easy way out. Give me the answer don't make me figure it out myself. I have been the most concerned about the accumulator knowing I should start by replacing it. Chuck had a very good thought about going with 2 separators but I have been down that path except, with the Rockler type setup, not your design. I think I will probably put my experience in troubleshooting to work and see where it leads. Maybe in the end I will have all new plumbing throughout maybe not, but I will have gained a lot of knowledge in dust control (good or bad).
Take a look at the photo below showing part of my DC piping. In particular look at the manifold above the floor sweep and jointer. Now imaging that turned upside down. That is what you should build. Get rid of the accumulator and put in two sweeping bends into two 45 degree laterals. I assume you have blast gates at each piece of connected equipment and only one of the 4" lines is open at a time. If so, I don't know what two separators is going to do for you.
(https://www.dropbox.com/s/kv8104vn419ve41/Manifold.jpg?raw=1)
Retired2: I had thought of a similiar setup after Vodkaman's suggestion but had not thought of 2 wyes with 45s and an end cap. I was trying to picture 1-45 off of the leg of the wye and 2- 45s off of the end to make a sweeping 90. I think either way would eliminate a short 90, which will take care of the inlet side. Then I can start working on replacing the outlet side short 90s with sweeping 90s. I want to thank everyone for your suggestions.
Quote from: Chuck Lenz on July 21, 2011, 09:12:29 PM
Quote from: retired2 on July 21, 2011, 07:43:21 PM
I assume you have blast gates at each piece of connected equipment and only one of the 4" lines is open at a time. If so, I don't know what two separators is going to do for you.
The reasons that I suggested two Separators is his Dust Collector has a 8" inlet, plus it moves alot of air. How big of a Separator drum to you think that you'd need to have an 8" outlet going to the DC and an 8" inlet in the Separator ? So I figured go with two managable size Separators, especially since he's useing two main trunks.
Chuck, I'm not sure I saw confirmation to my assumption that only one 4" line is bing used at a time. If both 4" lines are operating at the same time I can see your point about two separators.
However, if only one of those 4" headers is operational at any one time, then only one separator would be operational at a time, so why have two.
I must admit that DC does look like overkill for a system built of 4" pipe and I'm surprised that adding the accumulator and separator produced a noticable drop in performance. It seems like we have a big air mover that is suffocating.
Rcox, If you only give your DC air from one piece of equipment at a time, try opening two blast gates simulateously, or even three, and see if the performance of your system improves.
What's the SP and CFM rating on your DC?
retired2: I do not recall the sp, but the cfm is rated at 1900. Before I built this separator, I had tried opening 2 gates on the same line with a resulting loss at any given tool. I understand you can only get so much air through a 4" line regardless how many gates are open. I just know the suction I had when using the original splitter that came on the dc and a 35' piece of flex hose that I moved from tool to tool and what I have now. I kept tripping on the flex and decided to try a central hard line setup. Because of installing the 2 main lines as I did I thought of using the accumulator and going to the 6" line through the separator to the dc. I decided to give the separator the old redneck test yesterday and trying to make it as accurate as possible so I disconnected the separator from the accumulater and placed my hand in front of it to check suction, then I disconnected the separator from the line to the dc and checked it the same way. Very noticeable difference in the loss caused by the separator. May need to look at what I have wrong there before going further. I wanted to test it this way because it takes all the elbows into consideration and just shows what the separator itself looses.
Rcox, you have a very good DC with far more capacity than the typical small shop. I checked the Powermatic website and if I had the correct model, you have over 11 inches of SP. By comparison my system is 1200 CFM and a little over 8 inches of SP.
I have been building my system over that past year and only now am ready to build the separator, so I can't comment on what to expect in suction loss due the separator. I can tell you I have one long run with pressure losses the just about reach the limits of my system, so if the separator adds a lot of loss, I may have problems.
Having said, that your test of your separator does seem to suggest a problem of somce kind. I would not have expected much suction loss when it is close coupled and no other loads.
The other thing you should be thinking about replacing your 4" mains with at least 6". You've got the equivlent of a fire truck pumping water through a 1/2" garden hose. Snap lock pipe doesn't cost that much more than plastic pipe and you can get long radius ells. I'm sure you don't want to start tearing out a system you just installed, but longer term that should be a goal.
Quote from: Chuck Lenz on July 23, 2011, 07:57:32 AM
I'm not so sure that an 8" inlet on the DC would support two 6" mains, I was thinking that two 5" mains would be more appropriate, a 5" line would support two 4" gates being open, but I wouldn't leave more then three open at a time on the whole system.
Chuck, my suggestion on 6" size was still based on the assumption that he is only running one machine at a time, so no matter how many 4" headers are coming into his accumulator only one is open at a time. If that is how he is running his system, 6" headers are a good compromise because that size pipe and fittings would have significantly less static pressure losses, and it would be readily available at prices that are still reasonable. By contrast, I doubt you could find much of anything in 7", and 8" probably gets a little costly and far exceeds the needs of his worst case user.
If he is running both headers open simulatneously two 6" headers only exceeds the capacity of the 8" inlet by about the same percentage as two 4" headers exceed a 5" inlet.
Actually Chuck, I think we are in total agreement. He's got a great DC, but to get maximum efficiency out of it he has to give it more air.
All good suggestions. Due to some extenuating medical circumstances with my wife I am limited on what I can spend, until we find out the expenses.
With that said, and I don't mean to whine just something we have to contend with, here is what my final plans are.
I will replace the accumulator with a 6" wye, bringing my 4" lines into it at this time. This will effectively make 1 "short" main line with the old mains branching off of it. This will make it very easy for me to start switching out to a 6" main as time and money allow.
Chuck, the separator drum does cave in moderately as long as I leave at least 1 gate open. If I close the entire system it will completely collapse the drum. I used a puffer bottle with talcum powder to check for leaks around the lid. I could detect no leak with the slight caveing in with 1 gate open, if I close the whole system and collapse the drum it does have a major leak around most of the lid.
Replacing the accumulator with the wye may or may not make any difference in the suction at any given tool, only time will. I will try Chucks idea about lowering the baffle and see if it changes the restriction and resulting suction. If I do not get the change I expect/need then I will remove the separator and run the 6" inlet straight back to the dc until I can get my shop replumbed and then I will start over using a different drum that will not collapse. Probably something like one of the thick walled blue 55 gallon drums that are almost indestructable. In my opinion, changing the duct work sounds like the very first step to achieve the potential of my dc. In the end I will have 1-6" main line with a branch going the each tool. Some tools I will probably leave with a 4" port and some, like the table saw I will probably cut in a 6" port.
I think I have learned more about how my system should work and what I need to do to get there. I would like to thank all for your input and help. A work in progress is what we have here.
Will post the results of lowering the baffle sometime next week.
Quote from: RCOX on July 23, 2011, 06:51:33 PM
All good suggestions. Due to some extenuating medical circumstances with my wife I am limited on what I can spend, until we find out the expenses.
Rcox, sorry to hear your wife is dealing with medical issues. I hope all goes well for both of you.
6" main ducting is the answer to your problems.
The 4" duct can only flow a best case scenario max of 400 CFM while a 6" duct can do double that at 800 CFM. There is probably not a single tool in your shop than needs more than 800 CFM. If anything a widebelt sander would require it when it has 3-4 4" or 5" exhaust ports.
The brute garbage can will withstand the force of this with zero problems, however having something like your DC pulling as much vacumm with a choked airflow will cause issues. A simple spring loaded bloow off valve could be built into your separator would solve this should the situation arrive.
http://www.jpthien.com/smf/index.php?topic=198.0
You could have 400' of duct work in your shop and as long as your runs were no longer than 30 feet your powermatic will not blink. Also, consider that you may not want to completely air tight seal all of your joints near your terminating drops. This will allow a little extra bleed as to not starve the beast when running only 4" pipe. However all joints along the main should be very tight.
The SP and CFM power of your powermatic will over come any issues with branch lines, elbows and wyes running 6" main ducting as long as you do it correctly and give you a constant max flow CFM that the duct is capable of.
6" (I believe 26ga) HVAC ducting is available at Lowes for a lot less money than spiral ducting and has worked just fine in the 3 shops I put it in.
Chuck: what is the optimum distance the baffle should be from the outlet pipe? I picked up some stand offs/long nuts whatever you want to call them to be able to add the length needed. If I remember correctly the baffle is currently 3 1/2" below the outlet. I will be working on it Tuesday and Wednesday.
Pitbull: I bought a 6" hvac wye from Lowes today to start my changes. You are correct about the price being lower. The wye was $10.98 + tax, I have already used some ells and they are only about $7.00 for 6". My makeover starts Tuesday.
Well boys and girls here is the first go round of findings. First let me say I was blonde before I turned gray at around 23. I will also man up and admit my mistakes.
The first thing I checked for was leaks, yes I found some detectable leaks around the lid, also some at the joints of the adjustable ells. No, I didn't fix them. Remember, 1 thing at a time. I also found that my baffle was actually even with or slightly higher than the bottom of my input. May or may not lower suction. Now for the largest thing. Chuck you were correct, my baffle was only 2 1/2" below the outlet. I really thought I had measured it but apparently not. The outlet was through the top 3", 1/2 the diameter of the pipe but I must have guessed at the rest. I did notice a very small amount of fine dust on the under side of the baffle.
I lowered the baffle to 5" below the outlet, which put it below the inlet +/- 2 1/2". Using the redneck test there was a noticeable increase in suction at the inlet vs only the line between the separator and dc. Also manifested same increase at the farthest point from the dc. Using that point for all of my testing I discovered that there was satisfactory suction for all my needs. Now here is the rest of the story. I noticed the turbulence in the accumulator to be about the same as it had been, when I opened a gate on the other line the turbulence smoothed out but I lost more suction than with it closed. It appeared to reduce suction about the same if it was partially or completely open. Better to leave the second gate closed. I also noticed that the entire bottom of the baffle was covered in fine dust. I tried changing the distance of the baffle from the outlet pipe from a measured 4" to 5 1/2". It seemed that the closer to the bottom of the inlet the less dust stuck to the baffle. How far below the inlet should the baffle be? I can cut off the outlet some if I need to, to be able to maintain the distance between baffle and outlet pipe. I also noticed that there was a change in amount of dust under the baffle depending on how I placed the wide portion of the baffle in relation to the inlet. Using the lexan window I put in the side of the can it was also interesting to see how the airflow swirls in the can in relation to where the baffle is placed also. Placing the baffle so you have the maximum amount of wide surface in front of the inlet cases the dust to swirl upwards and pile the dust in a swirled ridge while placing the wide portion where the inlet is in the first third gives you a more flat swirl and lays the dust flatter in the bottom. I don't know what all this means yet but it has opened my eyes. Will have more time to play around with it tomorrow. More to follow. Any suggestions from this rambling will be appreciated.
These are only my ideas and opinions and should not be taken as fact or gospel. I throw them out there for discussion only.
First off, great post, full of good information.
Accumulator – here is a highly speculative and over simplified diagram of what I think is happening inside the accumulator. On the left, a single inlet open, on the right, both inlets open.
(http://i186.photobucket.com/albums/x36/folicallychalled/accumulator.jpg)
When the flow passes a sharp corner, edge or even a sharp bend, a low pressure is generated on the lee side. This is caused by the air having momentum. The air wants to travel in a straight line. However, some of the air is pulled over by the low pressure, effectively reducing the diameter of the inlet pipe. This peeled off air has nowhere to go and quickly degenerates into chaotic flow or turbulence (red). All the sharp edges on the lee side of the accumulator just make things worse, churning up the air. Some of this turbulent flow will oppose the main flow and slow it down some. The same thing happens at the edges of the inlet and outlet pipes (blue). Even a regular ‘Y’ will have this turbulence, it cannot easily be avoided.
With both inlets open, the main turbulence (red) is replaced by a different pattern. It is more organized and so appears to be less of a problem, but it is still destructive to the flow efficiency. This flow is called vortex shedding and it alternates left and right (this should be visible). If you Google ‘wiki vortex shedding’ the first entry on the list will be a Wikipedia page, at the top of that page, you will see an animation of what is happening.
Here is the link: http://en.wikipedia.org/wiki/Vortex_shedding
As the vortices flow downstream, they constrict the middle of the outlet pipe (until they eventually merge into the flow), effectively reducing the diameter. Even though they look harmless, this is probably causing more of a problem than the single inlet in the left diagram.
There are things that can be done to reduce the problems: Extending the inlet pipes in at an angle, until they touch, should remove the vortex shedding problem. Filling/fairing all the corners will reduce the blue disturbances, but the best solution would be to fit a proper ‘Y’.
Inlet and outlet relative height – I am not convinced that this is significant. The inlet flow will take the easiest route, which is down the centre of the chamber. If the inlet is aligned with the chamber centre then there is no change of direction. Probably below centre is more accurate, as the outlet will tend to pull the overall flow downwards.
What I think is critical, is the height of the outlet relative to the flow centre or indirectly, to the baffle. Every build will have a slightly different flow, so any numbers provided can only be considered a starting guide. You will have to adjust or tune the height to find the most efficiency.
Dave
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.
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.
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.
Quote from: RCOX on July 28, 2011, 05:15:50 AM
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.
Quote from: Chuck Lenz on July 28, 2011, 12:41:27 PM
Quote from: retired2 on July 28, 2011, 09:07:46 AM
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.
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.
Quote from: RCOX on July 28, 2011, 04:53:01 PM
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,.."
Quote from: RCOX on July 27, 2011, 08:38:35 PM
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
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.
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
Quote from: RCOX on July 29, 2011, 05:24:24 AM
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.
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.
Quote from: RCOX on August 03, 2011, 12:46:44 AM
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.
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
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
I haven't used a lot of plastic cans. I'd go with the metal, if you can make it work.
Chuck: the airflow restriction problem, as I see it, is trying to pull 6" air through a 4" pipe. I think it is more noticeable when I have the baffle in the correct location. I have seen the site you referred to but it has been a while since I have looked at it. I know there has been a lot of discussion about location of inlet to baffle. Looking at the page you referred to shows the top inlet with the discharge almost in the center of the baffle plate. With my side inlet, I think I have the baffle/inlet relation about the same at this time. It seems to me that with about a third of the baffle in front of the centerline of the inlet is where I get the best suction. At the risk of trying to over analyse this design I am trying to determine what "causes" the differences. I think that with the baffle further to the front, I am losing some suction up through the slot and going back into the incoming airflow instead of providing separation. With the baffle further to the rear, the baffle retards the uprising airflow until it has had time to settle/drop more of the dust. If I am half way correct, this is also why I notice more suction and collapsing of the can walls. I know this is a lot of rambling but I work better when I can understand why/how something works instead of just doing it.
Phil: I have a 30 gallon metal trash can that my complete setup will work in. The top of this can is just a little bit smaller in diameter so I will have to trim the rabbit a little more, then I will need to install the inlet and it should work fine. I have started getting some 6" pipe and fittings and will start switching that out in the near future. I am still trying to decide whether to use double 45's or switch to flex hose from the separator to the dc to eliminate the sharp 90's.