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#91
I can only upload 1 picture at a time due to size.
#92
Hello everyone that hears me!!
I have a situation that needs addressing. I am hoping to make continual tweaks until I get this thing dialed in. My first change was lowering the baffle 1 1/2". I originally had it adjusted to about 1/2" below the 45 degree inlet. My next thought is to adjust the angle in which that inlet is currently set. I would love to hear some feedback of what I am doing wrong. I will post more pictures or take more measurements to work through.
Thanks ahead of time for your time....

Nate
#93
Thien Cyclone Separator Lid Discussion / Re: Introduce yourself...
Last post by mudgel - May 08, 2021, 07:31:48 AM
Hi everyone, I?m Mike. I live in Australia on a 0.5 hectare plot of land with my wife and 2 cats in a small rural hamlet about 180 klms West of Melbourne.
I have a metal clad (ColorBond) workshop 9m x 6m  with a 2.7m wall height and a roof pitch of 22 deg. There?s no ceiling or internal lining boards but it is fully insulated so tolerable in both summer and winter. It?s divided into the equivalent of a 2 car garage space inside (6m x 6m) with an attached single car space carport (3m x 6m). All built on concrete slab. 
It?s a real mess having been storage for the last 10 years or so and needs organising and tidying before it can become a useful workshop. I?m 67 and my health situation makes any project a slow moving chore. I have been known to complete jobs eventually. I do a little frequently so getting I?m getting a little more control over the space each week.
Anyway I?ve been drawn here by the mystery that is Dust Extraction/Filtration and not having any brings home that it must become a priority for my next project.
I?ve been watching quite a lot of YouTube and have settled on a design inspired by young Marius Hornberger?s channel and his construction of what he called his ?small dust extractor.? Matthias Wandel is my biggest inspiration and have brought a few of his plans to life.
Thats it for me - hope to chat with some of you as time passes. Thank you Paul, for generously sharing your space and your ideas.
My workshop comprises an assortment of hand held power tools (mostly 18v Makita) along with a floor standing pedestal drill press and an Evolution Rage 5S 254mm contractors table saw. An assortment of small bench tools like a combination disc and belt sander, bench disc grinder, spindle sander and a 230mm band saw with a very meagre 65mm cutting height completes my setup. Oh I have a 3HP 75litre belt drive air compressor too.
Writing it all down like this makes it seem so much - I guess I?m fortunate to have so many tools readily at hand but every project and video I watch, reminds of things like a jointer, thickness planar, decent bandsaw and table saw (all the expensive tools) that I?d love to have one day. My age and health probably don?t make them realistic goals but a dust extractor with some air filtration is a must.
Now that Ive committed my self in writing to undertaking this as my next project , I?ll have all the motivation I need to get it done. Wish me luck.
#94
Thien Cyclone Separator Lid Discussion / Re: Airflow measurements
Last post by Schreck - April 03, 2021, 10:28:14 AM
6" inlet extended into the blower housing

I modified the 6" plywood inlet so the pipe extended 1/2" into the blower housing.  I then measured airflow and motor performance with both 5" and 6" ducts.

The charts below show data for the 6" plywood inlet plate, initially with the pipe ending flush with the inside face of the plywood, then with the plywood rounded over, and finally with the pipe extended 1/2" into the housing (6" tight inlet).  The tight inlet showed the best performance and the highest efficiency.  The best inlet/duct size combination was to use the 6" tight inlet to draw from 5" duct through a 5-6 reducer. 
#95
Thien Cyclone Separator Lid Discussion / Re: Airflow measurements
Last post by Schreck - April 03, 2021, 10:14:48 AM
Quote from: Hoota on April 03, 2021, 08:20:13 AM

[quote ] The load current of an induction motor shafted to a fan inside of a housing is purely based upon how much the output flow is restricted.  A completely open output causes the motor to draw maximum current, maybe even exceeds the rated load stamped on the tag.  Always restricted the output of the fan housing slightly to prevent burning the windings to toast. When the fan housing output is restricted, the shaft spins slightly faster (less load) and load current declines.  Should the intake be restricted, there is less air mass available to the fan blade to draw upon, motor rpm is increased and load current will reduce (slightly).  Measurements should use pressure deltas inlet vs outlet and mass flow volume (ft^3/min?).  This type of problem is a mass flow and finding the solution on the curve is a differential equation.  Set up the parameters and Excel has Goal seeker app to solve differential equations for these particular problems.   
Thanks for that explanation, Hoota.  The first measurement I made was motor amperage to be sure I had enough restrictions.  At 9.5 amps/240 volts, the blower is drawing almost as much as the nameplate of 10 amps/220 volts.  I will measure the blower without the filter ring, 5" flex hose and outlet flange fitting and post the results.  I'm less interested in the pressure across the blower (inlet to outlet) than its capabilities on the suction side, because my eventual installation will have an outlet plenum and pleated filter.  My immediate decision is whether to install 5" or 6" ducts. 
#96
Thien Cyclone Separator Lid Discussion / Re: Airflow measurements
Last post by Hoota - April 03, 2021, 08:20:13 AM
Quote from: Schreck on March 15, 2021, 09:22:16 PM
In each case the flanged pipe showed higher velocity and lower static pressure than the raw pipe end.  When the reducer was tested, it showed a further increase in velocity and reduction of static pressure. 

Note how little the motor amperage changes.  Measuring changes in motor amperage is often cited as a way to determine whether more work is being done by the blower, which generally means it is moving more air.  The changes I measured are very small, which would (incorrectly) indicate small changes in airflow.  As motors become more loaded, the amperage increases but so does the power factor and it is the product of the amperage and power factor that reflects the change in work being done.

The table below summarizes the data behind the charts and it includes watts and power factor.  My blower motor is showing a very low power factor: 0.65 when loaded versus 0.80 or higher for good quality modern motors.
[quote ] The load current of an induction motor shafted to a fan inside of a housing is purely based upon how much the output flow is restricted.  A completely open output causes the motor to draw maximum current, maybe even exceeds the rated load stamped on the tag.  Always restricted the output of the fan housing slightly to prevent burning the windings to toast. When the fan housing output is restricted, the shaft spins slightly faster (less load) and load current declines.  Should the intake be restricted, there is less air mass available to the fan blade to draw upon, motor rpm is increased and load current will reduce (slightly).  Measurements should use pressure deltas inlet vs outlet and mass flow volume (ft^3/min?).  This type of problem is a mass flow and finding the solution on the curve is a differential equation.  Set up the parameters and Excel has Goal seeker app to solve differential equations for these particular problems.     
#97
Thien Cyclone Separator Lid Discussion / Re: Introduce yourself...
Last post by avracohen - March 28, 2021, 11:12:28 AM
Avra Cohen: cabinetmaker and avid scuba diver. I am a volunteer diver at the NY Aquarium. I am well familiar w/ cyclonic dust collection, now looking to build an underwater model that will separate out sand. We have powerful vacuum w/ 2" hose built into the exhibits, but need to separate out sand to redeposit it elsewhere in the exhibit, while keeping it from getting into the system where it will chew up the impeller.
Welcome any thoughts on modifications that would be useful or thoughts on consideration of the difference between airflow vs hydrodynamics. I think a Thien baffle will be needed for the same reason it is appropriate for sawdust collection.
#98
Thien Cyclone Separator Lid Discussion / Re: Airflow measurements
Last post by Schreck - March 20, 2021, 11:39:59 AM
For one of the duct configurations I measured velocity with both the pitot tube and a pinwheel meter.  This was a 10 foot long 5" duct with a 90 deg. elbow, 5 feet of duct and another 90 deg. elbow.  The pinwheel meter showed 6393 feet/minute while the pitot tube measurement showed 4660 feet/min. which is 27% lower.  Could part of the reason for the discrepancy be that the pinwheel meter partially blocks the end of the duct? Other tests where I partially blocked the end of the duct showed reduced velocity at the pitot tube, so I don't think this is the case.  The inlet to an elbow was probably not the best place to try this measurement...
#99
I used a 1/2" radius router bit to round over the inside of the 6" plywood inlet plate, thinking this might be beneficial.  The original steel inlet plate brought the 5" steel inlet pipe into the blower housing by about 1/2", so it terminated much closer to the impeller than my plywood 6" inlet. 

The chart below includes the rounded-over 6" inlet and adds measurements for the other inlet-duct combinations at low flow/high SP conditions.  These measurements were made by partially blocking the end of the duct with a flat piece of foam board.

The 6" inlet rounded - 5" duct measurements show degraded blower performance.  The result of rounding over the inside face of the plywood inlet was to make the blower less efficient by increasing the distance between the impeller and the housing.  I could correct this by extending the 6" duct further into the plywood inlet, closer to the impeller.

#100
I tested the 2 HP Grizzly blower to see whether it could support 6" ducts.  The blower has a 5" inlet and I tested its performance with 10 or more feet of 5" duct and again with a 5" to 6" increaser and 10 or more feet of 6" duct.  Then I made a 6" inlet for the blower and repeated the tests.  The first chart shows the CFM versus static pressure (fan curves) for all four combinations of duct and inlet.  All of these measurements were made with a raw duct end, i.e., no flange or reducer fitted as an increaser. The performance appears to be similar with the exception of the 5" inlet driving the 6" duct. 

The second chart shows the real impact of the change in duct size.  With the larger duct, velocity drops to the point where any further resistance in the ductwork, separator or filter would result in a velocity too slow to collect chips and sawdust.