J. Phil Thien's Projects

I've participated in a few threads regarding plugs in the separator, and it seems that when they occur, quite often ithey start at the end of the drop slot and quickly back up until the entire slot is closed off.  These plugs occur most often with stringy planer shavings.

Since I have personally experienced the problem, although in my case the shavings were very wet,  if I were rebuilding my separator tomorrow, I would end the drop slot with a slight tear-drop shape.  I would not exaggerate the shape, but a subtle budge might be beneficial!

So, there you go folks, a new idea you can run with!

I recently got a notice from Dropbox (the service I use to host all my web photos) advising me they will be eliminating public folders and making them private in March.  When that happens every photo I have posted in web forums will appear as bad links!

Not exactly sure what I am going to do, but I am open to suggestions.  I suspect there is no option that will avoid having to go back and create all new links, a daunting proposition!

There are a number of remote start/stop systems available for dust collectors.  Each has its own advantages and disadvantages.  The one I chose is Penn State Industries' Long Ranger Multigate system.  One of the disadvantages of this system is the frequent cycling of the blower as you move from tool to tool.  As a result, I have had four Long Ranger units fail in as many years - the relay seizes and then the blower won't shut off.  The Long Ranger is just not up to the task of cycling a 1-1/2 HP motor frequently.

Despite the problems, I like this system and do not want to change to another, especially since my blast gates are already wired with switches for this system.  So, I decided to build my own improved version of the Long Ranger using heavier components.   

Before I share the details of what I've done, I need to make this disclaimer.  I am not an electrical engineer, controls engineer, or electrician.  If you choose to duplicate any part of this design, you do so at your own risk.  If anyone reading this thread is qualified to critique this design and fabrication, I welcome your comments.

Just for reference, here is a photo of the old, actually brand new, warranty replacement Long Ranger Multigate system. Inside the metal enclosure are all Asian solid state components.  I'm thinking about using this one to control a 7W night light, it should be able to handle that service!





Below is a photo of the unit I built.  All components are housed in the hinged-door NEMA enclosure approximately 7"x7"x5"deep.  The first improvement can be seen on the door.  It is a simple spring-wound timer that controls all power to the system.  It is time-selectable up to twelve hours, and its primary purpose is to provide peace of mind by ensuring that the system will be without power when I am not in the shop.  Although it has never happened, the micro-switches on the blast gates could vibrate loose.  If one were to move just a small amount, the blower would start and continue to run.  That would not be a good thing if I were away on vacation!




The next photo is the enclosure with the door open.  Inside is a 120V contactor with a 120V coil, and a small white device which is an adjustable stop-delay relay.  This device is the second improvement in my design.  It allows me to set a delay interval in the shut-off.  This provides time for me to move from one machine to the next without cycling the blower.




Here is a close-up of the inside of the box showing the wiring details, and a better view of the delay relay.  On the relay you can see the pot for adjusting the delay interval and a bank of dip-switches that control the numerous functions of the relay.  This relay also simplifies the triggering of the unit because there is no transformer required to provide a low voltage circuit for the blast gate switches.  The relay is triggered by the "dry" closing of any of the micro-switches; no voltage is required.




And finally, here is a copy of my wiring diagram.  As I said, I am not an electrical or controls engineer, so the symbology may not follow standard convention, but it makes sense to me.




So far, the unit is performing exactly as planned.  Only time will tell about the long term durability.  The total cost for the various components is about $150, cheaper than buying a Long Ranger every couple years, or replacing a blower motor prematurely due to repeated cycling.  If anyone is interested, I will provide a parts list, prices, and sources.

Today for the first time my separator failed me, amd caused me one monstrous headache.  Actually, I overwhlemed it till it finally succumbed.

If you want to give this a try, here is what you need to do.  Start by getting about 100 bd.ft. of wet cypress, it helps if it is covered with a little snow and ice.  Just use a paint scaper to remove the ice, and promptly start planing.  The wet cypress will produce very long, very wet, and very clingy shavings.  Don't bother to look at the separator while you are planing.  When the thickness planer starts throwing shavings back at you, the waste drum is full.  Please note, this does not take very long!

By this time the waste drum will be overfilled, and the separator will have ingested enough shavings to choke it to death.  You won't even be able to see the bell mouth in the center of this giant birds nest. Sadly, the normal setup with a Delta 50-760 DC does not lend itself to an emergency tracheotomy.  I knew what had to be done so I started by removing and dumping the over-filled waste drum.  This was followed by tediously roto-rooting the separator chamber till it was clean.  Oh yes, the filter bag and the plastic bag below it were not happy either, so they had to be cleaned.

After a lot of lost time I thought I was ready to go again.  Sadly, the DC was still not breathing - the filter bag just hung there limp.  I feared the worst, a plug in the main, but when I removed the flex hose connected to the inlet of the separator, it still was not breathing.  How can that be, the separator is whistle clean? Is the impeller not turning?  Yes, it is, but pulling the motor and impeller looks like the only way to know what is going on inside.

More lost time, but when the motor and impeller were out I was able to look down the throat of the inlet piping and immediately see the problem.  Remember those slick 1-1/2" plastic tube air straighteners I installed that improved the performance of my system?  Well, they weren't intended to pass 3" long wet cypress shavings.  They were packed full, and not allowing anything to pass.  So, with the motor out it was easy to push the plugs out.

After an hour or more, everything was back in working order.  However, the rest of the day did not go much better.  I had several more birds nests, even when the waste drum was less than half full.  A wider drop slot might have helped a little, but many of the plugs started when shavings caught in the end if the drop slot, and in seconds they would pile up like a snow drift, and promply close off the entire length of the slot.

Note to self: next time design to minimize blockages and facilitate their removal.

I have never seen such long stretches of silence.  Surely, folks have returned to their shops to make X-mas gifts for family and friends.  If nothing else you should be spending some time there to justify your own tool wish list!

And what are all of you folks doing that are looking at the the thread for my build?   Every few days the "view count" goes up by a hundred or more.  Surely, some of you are looking because you are actually building a separator!  Let's hear from you.

In a very recent thread Phil made the comment that the primary benefit of a 2H (double-high) separator is the reduction of waste by-pass that results from the outlet pipe being lower than the inlet pipe.  That jogged my memory about some interesting test data I collected using three different positions for the outlet pipe.

That data shows that a straight outlet pipe passed essentially the same amount of air regardless of position.  However, the bellmouth moved more air as it was moved closer to the baffle.  The increase is not huge, but it is large enough and consistent enough to suggest it is real rather than a test procedure aberration.

The question to be explored now is whether the optimum location for a bellmouth outlet pipe is lower than the conventional 2-1/2 times the pipe diameter in a 1H (single-high) separator?  And of course the follow-up question is where is the optimum location for a 2H unit?

Since my build now has the outlet pipe solidly anchored, it is very difficult for me to go back and do further testing.  So, this thread is for those of you who have a bellmouth build in progress, or have a bellmouth outlet pipe that is still adjustable.  Do some testing and share your results here!

Regards,
Retired2

For all of you folks trying to find that next performance enhancement for your top hat separator, here is something to ponder, and possibly try.

Have you ever noticed that a top hat separator with a tangential side inlet looks very much like a centrifugal fan without an impeller, the major difference is the air flow is reversed, i.e. the outlet is the inlet, and the inlet is the outlet.  The other far more subtle difference is that top hat builds always have the outlet port centered, while that same port on a fan is always off-center.

So, the question becomes, is the outlet port in top hat builds in the optimum location, or sweet spot?  Is there a slightly off-center location that improves flow rates?  :D

Common misspellings for "separator":

seperator (88%)
seprator (4%)
seperater (4%)
separater (3%)

Anyone who has built a top hat separator, or just read the threads by people who have, know that the most challenging part of the construction is the side wall.  Many different materials have been used, and each seems to have its own set of problems.  And of course, the real challenge lies with securing and sealing the wall material.

I chose plexiglass for my sidewall, and like others who have used it, I cracked mine while securing it with screws, and that was in spite of taking extreme care.  So, I started to think about how sidewalls could be secured without mechanical fasteners that project into the airstream, or dados that create a ledge at the drop slot, or messy glues that make an otherwise neat construction look sloppy.

At this point my proposed solution is merely conceptual and it needs to be developed and tested further, but it builds on the design used for my first separator and shared in the thread titled:  " 5", Rectangular Inlet, Bellmouth outlet, Top Hat Thien Separator".

Here is a revised sketch of my original design showing the needed changes.  First, the plexiglass retaining rings now show a 1/8?x3/16? dado that I added during construction of my separator.  But, new to this design are 1/8? radially drilled holes that intersect with the dado.  The drilled holes will be used to inject adhesive from the outside, and the spacing of the holes will be determined by the viscosity of the adhesive.



The following photo was taken during the construction of my separator.  It shows the dado being cut with a slot cutter.  In my build, this dado was filled with rope caulk prior to installing the plexiglass.  However, in my new concept no rope caulk will be used.  Instead the plexiglass will be installed over the open dado, but it must fit tightly or be held temporarily by clamps.



Once the plexiglass is securely in place, the adhesive is injected from the outside through the radial holes.  Here is a video showing how that might work.  Sorry about the video camera not being able to hold focus.

VIDEO
https://www.dropbox.com/s/ug17hdaqsyw4tkp/Separator%20Concept.MPG?dl=0

Well, I finally had several good days to begin the construction of my Thien separator.  Here is a photo of the nearly finished product.  I need to secure the plexiglass and seal some joints, then I will be ready to test the bellmouth outlet.  However, before I do another thing, I need to do some serious cleaning of my shop - remind me not to use MDF again!  Also, before I can test, I need to do some work on my DC piping.

If you have interest in seeing some of the sequential construction photos, let me know and I will post more.  I've included just one so you can see the bellmouth attachment.

Here's a link to a dust collector test that has been posted here before.  It is a good report on dust collector performance, but it also contains a small inset on the lower left corner of the last page that might get overlooked.  The inset discusses the performance improvements of a bell mouth pick up port vs square cornered pick-ups.  Their testing showed improvements of more than 100cfm and a drop in SP of 1" for a bell mouth shape.  That's pretty significant.

http://www.portercable.com/uploads/PCD/Documents/News/182DustCollectors.pdf

So, the question becomes, would a bell mouth outlet on a Thein separator provide some level of improved performance.  It sure seems like it might be worth a try.

Has anyone done this? 

Phil, I've searched the forum for threads discussing separator diameter, and was not able to find much specific guidance on minimum or maximum size, probably because most people simply let their container determine the diameter.

I have a Delta 50-760 and I plan to build a top hat design with 5" inlet and 5" outlet".  I might build a rectangular inlet based on the previous discussion we had.  I currently have a Brute 20 gal plastic garbage that I plan to use with the separator.  The inside diameter is 17-7/8".

My first thought was to mount the top hat right against the underside of the DC.  However, I quickly discovered that would limit my separator diameter to 16", or possibly less, due to the adjacent flange on the chip bag.

If I drop the separator down, I can build it with a diameter of about 17"(to match the 20 gal Brute).  That's not a great deal larger, but to go bigger I would need a 30 gal can.

So, the question is, based on your experience and testing, what comments or suggestions can you make on diameter?

When I decided to make my DC stationary and pipe everything to it, I knew I would be stretching the capacity of my Delta 50-760.  So, I decided I would do everything I could to minimize line loss and turbulance.

Below is a picture looking into the lateral branch of a typical HVAC wye.  As you can see, the fabrication method results in many small tabs
facing into the direction of air flow.  It seems to me these tabs are a source of unnecessary turbulance and increased friction loss, and possibly even a birds nest if you are conveying heavier shavings or stringy material.

The second photo shows a wye after I covered the tabs with "Lab Metal", and sanded it smooth.  This modification may only make a tiny improvement in the performance of my system, but it has to be better than stock wyes.

Thirty-five years ago, when I bought the bandsaw in the following photo, no one ever dreamed of dust collection in a small shop as we know it today.  All you hoped for was a dust chute that put most of the dirt in a neat pile on the floor so it could easily be swept up.  Powermatic's idea of a dust chute on their 14" bandsaw was a 2" pipe stuffed in the throat just below the table top.  It captured about 50% of the dirt - the rest accumulated inside the saw until it started coming out every crack until there was dirt everywhere.

When I got my Delta 50-760 DC I figured this would be the easiest tool in my shop to contain the waste - NOT!  I really didin't expect my first attempt to work because I just hooked the full force of the DC to the 2" pipe and hoped for the best.  It sucked up the 50% of the dirt that the chute previously sent to a neat pile on the floor, but the other 50% still went everywhere.

So, I thought about the problem for days until finally I decided I needed a new dust port, a real one.  So, I took the steel door off the bandsaw and took it to a local fab shop and asked if they could burn a neat 4" hole in the door where I had marked it.  The guy I deal with said no problem.  He could see the pain that cutting a hole in my bandsaw was causing me so he advised me to take two aspirin and come back in the morning with several dozen assorted donuts for the guys in the shop.  That's all it cost me.  They did an nice job, but I spent the next few days recovering from the surgery.

This is a photo of my finished installation, but not the end of the story:



Once the two dust hoses were connected as shown in the above photo, dirt was still escaping around the throat just below the table top.  The lower blade guides were the problem.  They form two 45 degree ramps that were deflecting the dirt coming out of the blade gullets.  Here's a picture before my modification.



Now I had to figure out a way to capture the deflected dirt and redirct it to the 2" dust chute immediately below.  The solution was a small box that snugs up to the underside of the table and wraps around the blade and lower guides.  This keeps the dust from escaping the vacuum stream below.  Here's two photos showing the box and how it is attached.






So, here's the lesson.  If you've got an old bandsaw that throws sawdust around in spite of being connected to a good DC, cut a real port in a strategic location, and everything will work much better.  Take my word for it, you and the bandsaw will live through it!!

Phil,  I'm getting close to building my first top-hat separator, and was wondering if any of your testing included variations of the inlet shape?  Most everyone goes to great pains to insert a round inlet pipe tangentially and then shape the end to match the inside diameter of the separator.  This makes perfect sense since the separation process is dependent upon spinning the dust laden air stream around the inside perimeter of the separator.

Since the objective is to get the waste against the outside wall, would it make more sense to use a retangular inlet that is taller than wide.  Also, key to this concept would be an "eccentric" transition piece that would go from round to rectangular, keeping the area roughly constant.  For example, my piping is 5" diameter so I was thinking of transitioning from 5" round to 5"x4" rectangular, or even 5.5"x 3.5".  My thinking is the transition piece to rectangular moves the air stream closer to the outside wall before it enters the separator body. 

An eccentric transition piece might be more difficult to fabricate, but it seems if a rectangular inlet is better, then the transition is optimal if it is eccentric rather than concentric.

Comments?