A Thien Baffle tested on a shopvac

[Jerome Hanby]

I am pretty sure that you can't get an enforceable patent on something you already published, so I hope you haven't spent too much on it.

I think you are probably misinterpreting the attempt to patent the concept for the periscope many decades after Jules Verne described it in 20,000 Leagues Under the Sea. Had Verne cared to apply for a patent, his prior publication would not have been an impediment. But a third party would not be granted a patent. So you would not be able to patent Phil's design, but Phill can. Pretty sure the flying saucer would fall into the same category

[Mike Henderson]

I think you are probably misinterpreting the attempt to patent the concept for the periscope many decades after Jules Verne described it in 20,000 Leagues Under the Sea. Had Verne cared to apply for a patent, his prior publication would not have been an impediment. But a third party would not be granted a patent. So you would not be able to patent Phil's design, but Phill can. Pretty sure the flying saucer would fall into the same category

I think that if the inventor publishes the invention, they have one year from publication to start the patent process or they lose the right to patent it. I know our patent attorney used to make us get a non-disclosure agreement (NDA) from anyone we talked to about patentable concepts just for that reason. By getting an NDA we were not publishing the concept.

Mike

[Tony Perrone]

Wade,
This is where your test is flawed, the particles you re-vacumed were staticly charged the first time around and would not give you a true base line to conduct your test. Also did you account for humidity and temperature changes for each time you did your test? Statisticaly speaking this test is invalid if all variables are not accounted for. ( I loved statistics in college) By the way I have a Thien baffel in my dust collector and I love it thanks Phil for the FREE information.
PS, Smile it's Wood working and it's supposed to be fun!

[Steve Ryan]

Just curious about something. I would feel like a complete idiot if my comment about someone's bad spelling contained grammatical errors. Is it just me, or is that a common feeling?

He started this thread and his second sentence was "Though I am wholly ignorant of fluid dynamics". That just about explains everything.

[Steve Ryan]

OK Time to get serious. Just how does the Phil Thein Baffle work? To know how it works you need a bit of info on how a cyclone works and I will explain that below later on.
The Thein Baffle is just that, a baffle. The dust stream enters the container through an elbow directing the stream into a somewhat cyclonic action in the upper chamber. Centrifigal force pulls the particles to the outside of the spinning stream where they settle down to the lower chamber. There is a fair amount of turbulance introduced into the container from the elbow to the stream comming into the container and the Thien Baffle smoothes that turbulance out and prevents it from stirring up the entire contents of the container. You may think that the 90 degree elbow would direct the incomming stream 90 degrees, and you would only be partly correct. A good part of the stream will be a lot less than 90 degrees because the stream will take the path of least resistance. It is this off angle stream that keeps the solids stirred up a non baffled container instead of setteling down. Phil, have you tried the seperator with a smaller outside opening and a center opening somewhat like the cyclone has? The youtube vid is very impressive for what it is doing, and I think a good part of that is how air is introduced into the chamber. Side inlet will have less turbulance to start with, and not have the back of the elbow to run into.
And now for how a cyclone works. Seriously, look up cyclone seperator on wikipedia.


Steady state
As the cyclone is essentially a two phase particle-fluid system, fluid mechanics and particle transport equations can be used to describe the behaviour of a cyclone. The air in a cyclone is initially introduced tangentially into the cyclone with an inlet velocity Vin. Assuming that the particle is spherical, a simple analysis to calculate critical separation particle sizes can be established.
Given that the fluid velocity is moving in a spiral the gas velocity can be broken into two component velocities: a tangential component, Vt, and a radial velocity component Vr. Assuming Stokes' law, the drag force on any particle in this inlet stream is therefore given by the following equation:
Fd = 6πrpμVr. If one considers an isolated particle circling in the upper cylindrical component of the cyclone at a rotational radius of r from the cyclone's central axis, the particle is therefore subjected to centrifugal, drag and buoyant forces. The centrifugal component is given by:
The buoyant force component is obtained by the difference between the particle and fluid densities, ρp and ρf respectively:
The force balance can be created by summing the forces together
This rate is controlled by the diameter of the particle's orbit around the central axis of the cyclone. A particle in the cyclonic flow will move towards either the wall of the cyclone, or the central axis of the cyclone until the drag, buoyant and centrifugal forces are balanced. Assuming that the system has reached steady state, the particles will assume a characteristic radius dependent upon the force balance. Heavier, denser particles will assume a solid flow at some larger radius than light particles. The steady state balance assumes that for all particles, the forces are equated, hence:
Fd + Fc + Fb = 0 Which expands to:
This can be expressed by rearranging the above in terms of the particle radius. The particle radius as a function of cyclonic radius, fluid density and fluid tangential and rotational velocities can then be found to be:
Experimentally it is found that the velocity component of rotational flow is proportional to r2[2], therefore:
This means that the established feed velocity controls the vortex rate inside the cyclone, and the velocity at an arbitrary radius is therefore:
Subsequently, given a value for Vt, possibly based upon the injection angle, and a cutoff radius, a characteristic particle filtering radius can be estimated, above which particles will be removed from the gas stream.

[David Hostetler]

WOW... That is impressive. Not sure how to even reply other than to say that is impressive!

OK Time to get serious. Just how does the Phil Thein Baffle work? To know how it works you need a bit of info on how a cyclone works and I will explain that below later on.
The Thein Baffle is just that, a baffle. The dust stream enters the container through an elbow directing the stream into a somewhat cyclonic action in the upper chamber. Centrifigal force pulls the particles to the outside of the spinning stream where they settle down to the lower chamber. There is a fair amount of turbulance introduced into the container from the elbow to the stream comming into the container and the Thien Baffle smoothes that turbulance out and prevents it from stirring up the entire contents of the container. You may think that the 90 degree elbow would direct the incomming stream 90 degrees, and you would only be partly correct. A good part of the stream will be a lot less than 90 degrees because the stream will take the path of least resistance. It is this off angle stream that keeps the solids stirred up a non baffled container instead of setteling down. Phil, have you tried the seperator with a smaller outside opening and a center opening somewhat like the cyclone has? The youtube vid is very impressive for what it is doing, and I think a good part of that is how air is introduced into the chamber. Side inlet will have less turbulance to start with, and not have the back of the elbow to run into.
And now for how a cyclone works. Seriously, look up cyclone seperator on wikipedia.


Steady state
As the cyclone is essentially a two phase particle-fluid system, fluid mechanics and particle transport equations can be used to describe the behaviour of a cyclone. The air in a cyclone is initially introduced tangentially into the cyclone with an inlet velocity Vin. Assuming that the particle is spherical, a simple analysis to calculate critical separation particle sizes can be established.
Given that the fluid velocity is moving in a spiral the gas velocity can be broken into two component velocities: a tangential component, Vt, and a radial velocity component Vr. Assuming Stokes' law, the drag force on any particle in this inlet stream is therefore given by the following equation:
Fd = 6πrpμVr. If one considers an isolated particle circling in the upper cylindrical component of the cyclone at a rotational radius of r from the cyclone's central axis, the particle is therefore subjected to centrifugal, drag and buoyant forces. The centrifugal component is given by:
The buoyant force component is obtained by the difference between the particle and fluid densities, ρp and ρf respectively:
The force balance can be created by summing the forces together
This rate is controlled by the diameter of the particle's orbit around the central axis of the cyclone. A particle in the cyclonic flow will move towards either the wall of the cyclone, or the central axis of the cyclone until the drag, buoyant and centrifugal forces are balanced. Assuming that the system has reached steady state, the particles will assume a characteristic radius dependent upon the force balance. Heavier, denser particles will assume a solid flow at some larger radius than light particles. The steady state balance assumes that for all particles, the forces are equated, hence:
Fd + Fc + Fb = 0 Which expands to:
This can be expressed by rearranging the above in terms of the particle radius. The particle radius as a function of cyclonic radius, fluid density and fluid tangential and rotational velocities can then be found to be:
Experimentally it is found that the velocity component of rotational flow is proportional to r2[2], therefore:
This means that the established feed velocity controls the vortex rate inside the cyclone, and the velocity at an arbitrary radius is therefore:
Subsequently, given a value for Vt, possibly based upon the injection angle, and a cutoff radius, a characteristic particle filtering radius can be estimated, above which particles will be removed from the gas stream.

[Bryan Rocker]

Wade,
This is where your test is flawed, the particles you re-vacumed were staticly charged the first time around and would not give you a true base line to conduct your test. Also did you account for humidity and temperature changes for each time you did your test? Statisticaly speaking this test is invalid if all variables are not accounted for. ( I loved statistics in college) By the way I have a Thien baffel in my dust collector and I love it thanks Phil for the FREE information.
PS, Smile it's Wood working and it's supposed to be fun!

Just remember there's statistics and dam statistics

BTW Phil, I would wager, Wade is what I would call a forum troll......You have done and continue to do a great service to the wood working community......My hat's off to you!!

Bryan

[Gary Lange]

I wonder who Wade Lippman is?

Pittsford Technical Services
23 Wood Stone Rise
Pittsford, NY 14534-3668 map

Phone:
(585) 385-8996

Website:
Information not found



About Pittsford Technical Services
Is this your company?

Pittsford Technical Services in Pittsford, NY is a private company categorized under Information Services, Consumer. Current estimates show this company has an annual revenue of 45,000 and employs a staff of approximately 1.

It appears this one employee is Wade Lippman. Interesting what information you can find on the computer and it is available to all who enter the name of this individual. It doesn't mean anything but he could get more work done if he wasn't harassing Phil and may increase his annual revenue.

[Ruhi Arslan]

Steady state
As the cyclone is essentially a two phase particle-fluid system, fluid mechanics and particle transport equations can be used to describe the behaviour of a cyclone. [...]

I am not an expert or even an unqualified self pro-claimed tester of dust separator systems but I think I could argue to the fact that (I have no basis to do so except having written my doctorate dissertation in constitutive modeling of biphasic micro structures) the subject continuum here is a mixture rather than a two phase system.



P.S. I also must admit that I should stop abusing my prescription strength cough medicine. First, recent few SS topics and then this one, provided me an endless source of entertainment in my sick bed during the last seven days.

[Prashun Patel]

My gosh! I've been following this thread and have been on the fence about taking the time to build a Thien separator. I gotta say that the irony in Wade's posting is that I'm DEFINITELY convinced now the Thien is the way to go.

Phil, I think the numerous, disinterested, and virtually unanimous anecdotal endorsements you've gotten here are worth more than any scientific test you'd ever concoct. They've convinced me.

[Brian Kent]

OK Time to get serious. Just how does the Phil Thein Baffle work? To know how it works you need a bit of info on how a cyclone works and I will explain that below later on.
The Thein Baffle is just that, a baffle. The dust stream enters the container through an elbow directing the stream into a somewhat cyclonic action in the upper chamber. Centrifigal force pulls the particles to the outside of the spinning stream where they settle down to the lower chamber. There is a fair amount of turbulance introduced into the container from the elbow to the stream comming into the container and the Thien Baffle smoothes that turbulance out and prevents it from stirring up the entire contents of the container. You may think that the 90 degree elbow would direct the incomming stream 90 degrees, and you would only be partly correct. A good part of the stream will be a lot less than 90 degrees because the stream will take the path of least resistance. It is this off angle stream that keeps the solids stirred up a non baffled container instead of setteling down. Phil, have you tried the seperator with a smaller outside opening and a center opening somewhat like the cyclone has? The youtube vid is very impressive for what it is doing, and I think a good part of that is how air is introduced into the chamber. Side inlet will have less turbulance to start with, and not have the back of the elbow to run into.
And now for how a cyclone works. Seriously, look up cyclone seperator on wikipedia.


Steady state
As the cyclone is essentially a two phase particle-fluid system, fluid mechanics and particle transport equations can be used to describe the behaviour of a cyclone. The air in a cyclone is initially introduced tangentially into the cyclone with an inlet velocity Vin. Assuming that the particle is spherical, a simple analysis to calculate critical separation particle sizes can be established.
Given that the fluid velocity is moving in a spiral the gas velocity can be broken into two component velocities: a tangential component, Vt, and a radial velocity component Vr. Assuming Stokes' law, the drag force on any particle in this inlet stream is therefore given by the following equation:
Fd = 6πrpμVr. If one considers an isolated particle circling in the upper cylindrical component of the cyclone at a rotational radius of r from the cyclone's central axis, the particle is therefore subjected to centrifugal, drag and buoyant forces. The centrifugal component is given by:
The buoyant force component is obtained by the difference between the particle and fluid densities, ρp and ρf respectively:
The force balance can be created by summing the forces together
This rate is controlled by the diameter of the particle's orbit around the central axis of the cyclone. A particle in the cyclonic flow will move towards either the wall of the cyclone, or the central axis of the cyclone until the drag, buoyant and centrifugal forces are balanced. Assuming that the system has reached steady state, the particles will assume a characteristic radius dependent upon the force balance. Heavier, denser particles will assume a solid flow at some larger radius than light particles. The steady state balance assumes that for all particles, the forces are equated, hence:
Fd + Fc + Fb = 0 Which expands to:
This can be expressed by rearranging the above in terms of the particle radius. The particle radius as a function of cyclonic radius, fluid density and fluid tangential and rotational velocities can then be found to be:
Experimentally it is found that the velocity component of rotational flow is proportional to r2[2], therefore:
This means that the established feed velocity controls the vortex rate inside the cyclone, and the velocity at an arbitrary radius is therefore:
Subsequently, given a value for Vt, possibly based upon the injection angle, and a cutoff radius, a characteristic particle filtering radius can be estimated, above which particles will be removed from the gas stream.

That's easy for you to say!

[Neil Brooks]

That's easy for you to say!

I THINK ... he forgot to carry the "1."

[Jay Maiers]

I THINK ... he forgot to carry the "1."

Lol!
Prashun, I'm almost in the same boat.
I've been trying to decide if I should build one or not. Now, I'm definately going to build

[Doug Colombo]

Prashun: +2
I am upgrading my system now and have been reading whatever I can about dust collection. I have to say that I was on the fence - is it worth the work to build this? But after reading this thread, count me in !!!
Phil - thank you for all of your hard work and for making it available to us !!!
Wade - thank you for starting the thread - look at all of the people that are now going to build and use what looks like a great addition to our shops ! That is why you started this thread correct ??

[Greg Cuetara]

Interseting thread thus far. I have a ridgid shop vac and have built a few Thien Baffels. The first was in a 5 gallon plastic container and I think Wade might be correct that it doesn't work. I did not have any luck with a 5 gallon container and thought I was doing something wrong. I have since bought a 35 gallon steel trash can and built a baffel to go on it. Ummm...I am not sure how it really works and I don't really care...all I know is that I have increased the suction power of the shop vac by quite a bit and as long as I don't let the chips overflow the trash can I get pretty much nothing in my shop vac. I know that I have cleaned it out and after filling up the 35 gallon container looked and there is NOTHING in the shop vac. Something else is that I was having a problem with the baffel at one point in time and I was a bit miffed until I realized that I did not correctly seal the baffel down to the top of trash can and once I did that it worked flawlessly.

On another note the Steel trash can that I bought gets sucked in each and every time I turn on the shop vac. I had a build a ring inside the trash can to help keep it's shape. I think I need to pick up a 55 gallon plastic drum because even the 35 gallon is a bit small. The 5 gallon just did not cut it but once I got a bigger can things worked great.

And a note to Wade. I have sucked up at least 25 gallons of dust and chips within a matter of minutes and have gotten NOTHING in the shop vac container. Probably easier to pick up dust and chips with a dust pan but it is much more fun to use the shop vac.

Keep up the good Work Phil!