SP Loss on Baffle and Tophat mods ???

[LoneShark]

Having read most ( if not all the posts and replies ) I'm impressed with all of the info here.   I'd like to thank J Phil Thein for all the hard work and the generous sharing of his information - kudos , hats off and a salute to you sir!!!   I'd also like to thank all those others that have contributed as well.   What a great collective mind we have !!

Having built the top hat last year - a wonderful mod to my DC system, I recently built the baffle for my Jet 1100.  It works GREAT !!!!   

My question is Static Pressure Loss for these two mods ----- has anyone measured the before and after??  Im just curious as Im about to re-plumb the shop, and we must be mindful of SP losses throughout the system otherwise its alot of wasted effort (and money) if not done correctly.

In reading many posts I'm not finding and true measured results ( I may have missed it - if so please point me to the proper post ).  If you have measured the SP Loss on these and would like to share the results I'd love to see them.

Thanks Again Phil,
LoneShark

[retired2]

Having read most ( if not all the posts and replies ) I'm impressed with all of the info here.   I'd like to thank J Phil Thein for all the hard work and the generous sharing of his information - kudos , hats off and a salute to you sir!!!   I'd also like to thank all those others that have contributed as well.   What a great collective mind we have !!

Having built the top hat last year - a wonderful mod to my DC system, I recently built the baffle for my Jet 1100.  It works GREAT !!!!   

My question is Static Pressure Loss for these two mods ----- has anyone measured the before and after??  Im just curious as Im about to re-plumb the shop, and we must be mindful of SP losses throughout the system otherwise its alot of wasted effort (and money) if not done correctly.

In reading many posts I'm not finding and true measured results ( I may have missed it - if so please point me to the proper post ).  If you have measured the SP Loss on these and would like to share the results I'd love to see them.

Thanks Again Phil,
LoneShark

There is quite a bit of measured data in the thread on my build.  At the moment that thread is directly above this one.  I measured amps, fpm, cfm, and noise level. 

While I did not measure SP directly, there is a link to a review of several DC's that has been posted several times.  That review includes performance curves for all the tested fans, including my Delta 50-760.  If you know the cfm's for a given condition, you can just read the SP from the fan curve.

Since no two fans have exactly the same performance curve, any given piping configuration will cause different losses for each fan tested.  The Delta has a pretty good performance curve.  Unfortunately, fan curves are not readily available from manufacturers, and there is an obvious reason for that.  Buyers are left to make decisions on stated HP and max CFM's, both of which are often inflated or determined under conditions that do not reflect real world operating conditions.

[Schreck]

...My question is Static Pressure Loss for these two mods ----- has anyone measured the before and after??  Im just curious as Im about to re-plumb the shop, and we must be mindful of SP losses throughout the system otherwise its a lot of wasted effort (and money) if not done correctly.

In reading many posts I'm not finding and true measured results ( I may have missed it - if so please point me to the proper post ).  If you have measured the SP Loss on these and would like to share the results I'd love to see them.

I have been reading the forum posts and find the most interesting threads are those where the relative performance of different system designs and configurations are discussed.  retired2 has a great thread on the Delta 50-760, which integrates the blower and the filter "ring" into one housing.  Dust collectors with a blower separate from the filter ring are probably more common, however.  The blower and filter ring can be re-arranged and therefore offer a number of possibilities to incorporate a separator and optimize airflow. 

Since I will soon be moving my shop into the basement, I am about to build a top hat that can be installed either before or after the blower.  Through work, I have access to test equipment (pitot tube, manometer, kW and SPL meters), so I intend to measure a few combinations and post the results.

Some of the configurations on my list are stock single stage DC, same with baffle, top hat before stock single stage DC, same with baffle in DC ring, top hat after blower.  There are many other tweaks that could be measured, but first I intend to look at the major component arrangements.  I am open to suggestions....

[BernardNaish]

I presume that you wish to provide yourself with an efficient dust collection system AND contribute to our collective understanding of Thien separators, in particular top hat designs.

To my mind there is no point in putting a baffle after the blower except in addition to one before the blower.

Two stage separators remove all but the smallest dust particles before the fan so that they are more easily removed from the system. This means the HEPA filter is used just to remove the fine dust and does not need cleaning very often AND they protect the fan vanes from being hit by lumps of wood or harder material that will, over time, dent and wear them away reducing their efficiency or even cause the fans catastrophic destruction.

Dust collectors often have very simple separators below their filter that direct debris down into a plastic bag. These bags are notoriously difficult to remove and empty because their fittings have to withstand positive pressure applied over a relatively large area. By contrast drop cans are easy to seal as the vacuum easily draws the can against a seal. It is worth installing a Thien baffle within the simple separators provided in DCs, providing and ONLY providing that a Thien top hat separator or a cyclone has also been installed prior to the fan. Fitting a Thien separator plate into the DC without, misses the point entirely. My guess is that after installing a pre-fan top hat Thien separator you will find you would not gain anything by fitting a Thien baffle plate to the DC itself.

Integrating a pre-blower top hat into the DC itself makes sense as it saves a lot of space and minimises any pipework losses. This is well documented so there seems to be little to be gained by experimenting with this as the work about losses are either self evident or the work has been done.

I suggest that you read Retired2s' contributions very carefully, and they are in more than one thread, as he poses several intersting questions the answers to which would help us all. His TH design does not have a space below the bottom of the rectangular inlet duct and there is a suggestion that separation is improved if there is a space about equal to half the height of the inlet duct? Then again it would be interesting to determine the best distance of the the bell end of the outlet pipe from the top of the separator and the baffle, for that set up? It would also be interesting to find out if the width of the rectangular inlet duct is of any great import, ie 1 1/8" wide? Does the length of the rectangular section of the inlet effect performance? Etc, etc. This all assumes you have air straightener straws fitted etc. as Retired2 does.

The key information is how much fine dust is removed and how much is passed onto the HEPA filter. The losses, motor amperage drawn and air flows can of course be investigated but are really only interesting if they tell us how to improve filtration.     

Secondary is how to reduce noise levels.

To be meaningfull you will need to standardise your testing method particularly how to feed in debris. Just throwing a handfull into a blast gate tells us nothing much. Passing several mounds of measured amounts (weighed) of identical material under a fixed inlet pipe at a standard rate (by a drive system of some sort.) in a way that mimics actual shop conditions. Suggest using sawn MDF as the test material as almost any system will get the coarser material out. Then weigh how much is collected in the Thien can. Express filtration efficient as: (weight of material in can divided by weight material collected ) X 100. This really interests me but I do not have access to labs as I used so it is more difficult.

Let me know if I can help in any way.    Bernard

[alan m]

i look for ward to your test results schrek
i dont think we have seen profetional testing results.
retired2 has great data but done without proper industrial tools. i wish i had acess to those tools.
the problem in what we are doing is that even the slightest mistake in construction can prove the diference between an idea being a failure and a sucess(i could add a feature and get no improvment in data but not realise that further tinkering could show improvment). unfortunitly the diy tools we have arent accurate enough to show exact changes