Dust collector "upgrade" and CFM readings

[Michael W. Clark]

Ah, but the air is going slower

Would not the velocity of 3350 vs 2500 be more important ?

Cheers, Don

I'm not sure I understand? Your OP was stating that increasing duct size reduced the flow,but it appears this is not the case if we use the velocity readings.

Yes, you want the higher duct velocity. A velocity of 2500 FPM is too low for wood dust, IME.

As far as importance, flow comes first to get the dust in the hood. The duct is sized for flow to maintain velocity.
Mike

Edit, I would agree based on your readings that the 5" is preferred over the 6" because the velocity is higher, not because of your flow readings. Your fan would need to do 700-800 CFM in the 6" to keep the velocity high enough.

[John Gornall]

I would like to see ongoing numbers with the system in use. The numbers will drop as dust accumulates in the filter until the filter needs cleaning. And I am interested to see if the numbers return to full capacity after the filter is cleaned or if cleaning the filter is only partially complete. I have a popular brand 3 hp dust cyclone system and in my specific situation the air flow slowly dropped until the system was not functioning adequately after about 3 months of daily use. I attempted to clean as per instructions without success, moved on to more agressive cleaning but never got adequate flow back. I now run the system without filter and direct vent and the system works well. With full flow the cyclone works exceptionally well with the fine dust going to the bin and outside the vent there is no sign of dust. After paying the price for a large hepa pleated filter and only getting 3 months I wasn't about to buy another without a solution for cleaning which would get back to full flow. These dust systems with filters are great on a planer or jointer collecting chips but it's a different situation on a sander. In my case it was connected to a single specialized machine crosscutting hardwoods with a pair of triple chip blades - nothing but fine sawdust that plugged the filter so that it couldn't be cleaned.

[Don Kondra]

I will report back John.

Can you say which filter you where using ?

Do you have at least 4' of straight pipe entering the cyclone ? Apparently that will impact it's efficiency. I have 8' of straight pipe before the first Y.

I purchased a Wynn filter based mostly on the square foot rating. The Oneida retrofit is 96 sq. ft., the Wynn is 300.

My thinking at the time was I didn't want any possible back pressure from the filter, thus giving me the highest possible CFM/velocity with a relatively small impeller.

For a one man shop, making one piece at a time, it will take me quite a while to reach your 3 month findings

But, what is in the dust bin right now is mostly fine dust from the band saw, SCMS and stroke sander. What is in the filter clean out box is the equivalent of running your finger across a table before a weekly household clean up...

My old canister filter would have been due for a half dozen turns of the beater bar and a quick blow with air !

Cheers, Don

[John Gornall]

Don, I have the V3000 3 hp unit a number of years old. There is 6 feet of 6" straight then 6 feet of 6" flex to the one machine - that's it. The cyclone is very efficient and no problem with loading the filter other than fines. When the filter was plugged I blew it from the outside with compressed air as per instructions. There was about a cup of dust in the bottom after. But the filter would not pass air. I took the filter outside and blew it out with a leaf blower - no improvement. I shop vacuumed the inside and outside - no improvement. I hosed and washed it and never got it to pass air. This was the 13" X 39" hepa as supplied a number of years ago. With no filter the cyclone works great. With the filter, nothing. I have some industrial dust control experience from long ago and it's clear to me that this system needs about 6 times as much filter area. The filter is marginal and with a little clogging by fines it tips into failure mode. But with no filter it works great. But I'm curious how filters lose their flow capacity in use.

[Don Kondra]

I think you are correct in that you have the wrong filter for your situation. A similar ClearVue system has two Wynn filters for a total of 600 sq. ft.

You might want to give Wynn filters a call, they could suggest a model to suit your needs...

http://wynnenv.com/

You don't list your location but I couldn't afford the heat loss in the winter by exhausting outside

Cheers, Don

[John Gornall]

Thanks Don, I'm going to stay with venting outside. Works just fine, no issues, and heat isn't a problem out west on the Island.

[Don Kondra]

Thanks Don, I'm going to stay with venting outside. Works just fine, no issues, and heat isn't a problem out west on the Island.

I wouldn't bother either, if I didn't have to

Cheers, Don

[Don Kondra]

Link to images...

http://s249.photobucket.com/user/don...r%20conversion

Cheers, Don

[Mike Chalmers]

Link led to nothing but pop ups for me. I hope they are nothing more than annoying and do not lead to malicious code.

[Larry Frank]

The fan type anemometer is not a very accurate way to measure velocity. It is extremely sensitive to how it held at the end of the pipe. Also, the calculations are off by the amount area that the instrument is blocking the pipe opening. It appears that it is about 10% of the opening and the cfm needs to be adjusted.

[Don Kondra]

Link led to nothing but pop ups for me. I hope they are nothing more than annoying and do not lead to malicious code.

Photobucket is famous for their pop ups, nothing overtly malicious about it

I use Windows 10/Chrome and have a pop up blocker installed. At most, I get one pop up "asking" to upgrade when I first arrive there..

Cheers, Don

[Don Kondra]

The fan type anemometer is not a very accurate way to measure velocity. It is extremely sensitive to how it held at the end of the pipe. Also, the calculations are off by the amount area that the instrument is blocking the pipe opening. It appears that it is about 10% of the opening and the cfm needs to be adjusted.

As long as the head is held in the same position for all measurements, the actual results are good enough to judge any changes made in the future.

Cheers, Don

[Mike Kreinhop]

I can see your gallery in Firefox and Safari, but when I click on an image for a better view, this is what I see:

DC_Screenshot.jpg

[Don Kondra]

I can see your gallery in Firefox and Safari, but when I click on an image for a better view, this is what I see:

DC_Screenshot.jpg

Thanks Mike.

The good news is the original images in this thread are hosted here on Sawmill Creek !

Cheers, Don

[Mike Kreinhop]

I am happy to see your setup and have what appears to be a similar dust collector, the Bernardo DC 350 CF. It's a 2HP 3-phase model and the only part I'll salvage is the blower assembly. I have the same Oneida Dust Deputy that you have, as well as a pair of Wynn 35BA222NANO filters and a pair of the matching Wynn filter pans.

My shop is a newly partitioned 25 square meter (about 270 square feet) section of my finished basement, so I don't want to take any chances with dust. My distribution will be 120mm steel tubing with 100mm reducers at some of the equipment. I can buy all of the ducting, reducers, flexible hose, gates, fittings, clamps, and brackets at the same store where I bought the Minimax SC2.