Dust Collection efficiency

Hi:
I have a Jet 1.5HP dust collector that I an using with a cyclone seperator. The collector has a 6" inlet with a 4" Y. I have one of the Y ports closed and the other going to the cyclone lid with a short section of 4" hose. Out of the cyclone I have a 4" Y with 2 blast gates going to two different areas in the shop. I have 30' of 4" going to the Table Saw and 20' of 5" going to the planer and jointer. When simultaneousely using the table saw and jointer I an not getting enough suction. I was wondering if I went direct from the collector with 6" to the seperator (reduced 6"-4" to get into the seperator) would there be an increase in efficiency. My concern is that the reduction from 6-4" at the seperator would eliminate any advantage? Any experience or thoughts with this would be appreciated. Thanks!
Eric
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I recommend replacing the pipe with 6 inch, even with the trash can separator. I'd also be sure to use smooth transitions from 6" hose on both sides of the trashcan separator.
Bill Pentz has placed a wealth of information at <http://cnets.net/~eclectic/woodworking/cyclone/DC4Dummies.html .
Jet rates the 1.5 HP DC 1100 at 1100 CFM @ 4 inches WC and a maximum pressure drop of 11.5 inches.
Plugging some numbers into the static calc spreadsheet available on Bill Pentz's pages gives this.
Table saw recommended CFM: 800 straight pipe run: 40' of 4" flex hose: 2' of 4" trashcan separator: 2.5" pressure drop good filter bag (< 5 micron) 1" pressure drop (30 micron bags are worse) bends and turns: none Total estimated pressure drop: 20 inches WC!!!!
That is clearly impossible; the DC1000 has a maximum pressure drop of 11.5 inches.
Lowering the CFM requirement to 400 CFM lowers the estimated pressure drop to 7.6 inches.
Using 800 CFM and replacing the 4" pipe with 6" pipe gives a pressure drop of 7 inches. Looking at the 1.5 HP fan curve at Bill Pentz's site, it shows < 100 CFM at 7" pressure drop. This fan curve won't match your system exactly but it should be in the right ballpark.
Using the 6" pipe and a 400 CFM requirement gives a 4.4" pressure drop. The fan curve shows about 450 CFM for a 1.5 HP dust collector at 4" pressure drop.
One problem with this is that 400 CFM in 6" pipe has a velocity of only 2,000 FPS; the minimum recommended velocity is 3,500 FPS.
The bottom line is that both your dust collector and ducting are both too small to meet the recommended dust collection standards. Though if you're happy with it, I'm happy :-). Upgrading the ducting would be a bigger improvement than just upgrading the dust collector.
Bob S
On 14 Sep 2003 19:28:09 -0700, snipped-for-privacy@animas.net (Eric Malone) wrote:

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Sounds like it would be worth a try.
You may need to go bigger to account for that long of run. You may just be asking for too much out of a 1.5 HP sucker. That is my guess. -- Jim in NC
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On 14 Sep 2003 19:28:09 -0700, snipped-for-privacy@animas.net (Eric Malone) wrote:

I think your problem is a the separator is robing you of flow. and 6" would help. getting oversized bags would help too. The dc it's self as stock really reduces the airflow.
--
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