outdoor exhaust dust collection ideas needed

[Bill Dufour]

Open the trash bin lid and let it flop down all the way. Set a piece of plywood ov r the top and drill holes in that as needed. Remember to remove the plywood and close the lid before pickup day.
That is the basic way it was done at the lab with a 30 yard dumpster Boss called for a pickup when needed so we could disconnect before hand. We actuallu used. a compactor bin. loaded from one end. They left the vented top on and had to bring back the same bin each time. I think it went to the botanical garden.
Bill D

[Michael Fink]

My DC is outside (under an eve). No filter on it. Works well; but stuff near it outside does get a coating of fine dust on it. I don't find the loss of heated/cooled air is that significant; I'm sure it is a lot of air being sucked out, but there's a whole lot of air in the shop to start with, so doesn't appear to have as much impact as I initially thought it might.

6in pipe going through the wall to the DC; then piped around the shop to all the tools. I'm very glad I did it this way, one less filter to maintain, and honestly, it's noisy. It's even noisy outside, so I'm REAL happy it's not next to me when I'm trying to use a tool/think.

[Nick Crivello]

Update for all those who replied:

Swapped in a 3ph 5hp blower with 14.5" impeller, increased exhaust sizing to 6", and dumping into two 55-gallon drums outside. Much better, ~67db outside and 70db inside shop while running.

Big dilemma is that the 6" mains are choking the new blower out. Already spent a fortune on 6" piping. Might start another thread on what to do on that front.

[Chris Parks]

Update for all those who replied:
Big dilemma is that the 6" mains are choking the new blower out. Already spent a fortune on 6" piping. Might start another thread on what to do on that front.

Unlikely as 6" will flow 1200cfm and will handle a 15" impeller (just). I run a 15" impeller at 70hz with no issues. It must be 6" end to end including a 6" or better port on the machine.

[Nick Crivello]

Unlikely as 6" will flow 1200cfm and will handle a 15" impeller (just). I run a 15" impeller at 70hz with no issues. It must be 6" end to end including a 6" or better port on the machine.

I tested the 5hp blower with open exhaust. It was 2400cfm at the 7" inlet. Dropped to ~1900cfm with a 6" reducer.

Through the system I have in place it's a max of 1250cfm at the ceiling port which is a 5' straight shot forward and 90 degrees down from the blower. Getting 800cfm from the 5" line under the saw and 600cfm from the 4" hose over the saw (at the same time).

The 6" lines are choking it big time.

[Chris Parks]

I tested the 5hp blower with open exhaust. It was 2400cfm at the 7" inlet. Dropped to ~1900cfm with a 6" reducer.

Through the system I have in place it's a max of 1250cfm at the ceiling port which is a 5' straight shot forward and 90 degrees down from the blower. Getting 800cfm from the 5" line under the saw and 600cfm from the 4" hose over the saw (at the same time).

The 6" lines are choking it big time.

You can't measure the airflow without dedicated expensive equipment you can only say it seems less or more. Forget impeller driven gadgets to measure air flow, they don't work nor do other common devices. They will give a result but you can't put that result into numbers.

[Nick Crivello]

You can't measure the airflow without dedicated expensive equipment you can only say it seems less or more. Forget impeller driven gadgets to measure air flow, they don't work nor do other common devices. They will give a result but you can't put that result into numbers.

Yes I don't have the fancy doodads, but if the same anemometer reads 1900cfm at a 6" inlet with open exhaust then 1250cfm through the same size hole with everything installed does that invalidate the reading?

In other words I don't really care what the 'true' scientific number/cfm is... just that the same device at the same size hole measured in the same fashion at two different points is showing a marked reduction. That's all I need to know.

Edit: call it 'relative' measurements if you like.

[Chris Parks]

Yes I don't have the fancy doodads, but if the same anemometer reads 1900cfm at a 6" inlet with open exhaust then 1250cfm through the same size hole with everything installed does that invalidate the reading?

In other words I don't really care what the 'true' scientific number/cfm is... just that the same device at the same size hole measured in the same fashion at two different points is showing a marked reduction. That's all I need to know.

Edit: call it 'relative' measurements if you like.

Forget the air flow and measure the current the motor is using, more flow = higher current draw.

[Nick Crivello]

Forget the air flow and measure the current the motor is using, more flow = higher current draw.

Hi Chris,

Just checked with an ammeter, about 5.5-6.5amps across each of the three wires. It's supposed to be a 5hp/14a blower. What does that tell us?

Edit: my thought is that low current = reduced load/efficiency and thus lower flow.

[Carl Beckett]

Another instrument that was eye opening to me, was a particle size meter. I bought one recommended by another member here (bangood?) - was about $50 and allows me to measure effectiveness of the overall system.

Similar to your philosophy but one step further; I dont care about air flow, I just care if is collecting dust and fine particles...

[Alan Lightstone]

Another instrument that was eye opening to me, was a particle size meter. I bought one recommended by another member here (bangood?) - was about $50 and allows me to measure effectiveness of the overall system.

Similar to your philosophy but one step further; I dont care about air flow, I just care if is collecting dust and fine particles...

I care about both, but Carl brings up a very good point regarding the real risks/hazards.

[Jason puckering]

Do you happen to have pictures of the inside of the box? I am doing the same thing.

Do you have neighbors?

I have my blowers shoot into a trailer. The air circulates, and I have baffles on the walls and ceiling. The air has to do a U torn to get out. The big stuff stays in the trailer, the fine dust blows out into the meadow behind the shop. I like this, because the animals using the sawdust as bedding have less fine dust. My nearest neighbor is 1/4 mile away.

[Chris Parks]

Hi Chris,

Just checked with an ammeter, about 5.5-6.5amps across each of the three wires. It's supposed to be a 5hp/14a blower. What does that tell us?

Edit: my thought is that low current = reduced load/efficiency and thus lower flow.

My apologies for missing this post, the higher the amps the greater the air flow. There are some really nifty digital read outs available that can be installed to monitor the motor load and they are very cheap.

[William Hodge]

Do you happen to have pictures of the inside of the box? I am doing the same thing.

The baffles are 2 X 4 studs on both walls and the ceiling, set on edge, every 2'. The studs also provide structure for the trailer box. Hardly any chips blow out. I have removable gate boards at the back.

I ran a 2 X 4 along the floor inside the studs so that the farmer's shovel doesn't catch on the studding. He comes with a truck, hooks up the trailer, hauls it away, and returns the empty trailer.

The trailer has a metal roof. It's real important to keep the sawdust dry.