DYI fume extractor ideas

[user.69169]

You procrastinator boys best get careful wid dat procedure. Way tings are dese days wid all de masked people runnin loose some prosecutor might call it premeditation and even conspiracy if you post bout de plans.

Compressor-
Get de intake 13 feet above ground, or high as you can, no hydrocarbon fumes. Dat why dive air machines suck from high up.
Can't penetrate de wall for intake run it out into soffit.
Make intake pipe at least 2x diameter of compressor intake size.
Scrap de Donaldson intake "filter" and replace wid a prechamber sized to primary piston volume. Put a housing in front of prechamber loosely stuffed wid chore boy SS sponges wid a few drops peanut oil on em to keep bugs out de machine and filter incoming air. Wash & reoil every 45 days, peanut plasticizes.

If you got 3600 rpm machine not even God can make it quiet.

Hang de machine from roof and gain floor space, make sure springs under de machine only half compress wid machine weight. Dat how dental office machines are built to kill sound.

If you wall machine in, you got a lot of heat to shed. Cuple mover blankets hung around machine like shower curtains kill off lot of sound and shaped right become chimney conducting heat up.

Use rubber hose to connect tank to pipe system. Do NOT use plastic hydraulic hose.

PEX will carry 150psi compressed air and PEX is cheaper den copper or iron.

 

[strantor]

I don稚 procrastinate, i simply schedule my projects 32 years in advance. That way they will all get done sooner or later, but there never delayed.

I like that. Going to have to remember that one.

 

[strantor]

Where I work, we package plastic pellets. We suck pellets out of rail cars with 100HP roots blowers; basically giant shop vacs with 8" suction lines. We buy the packaging equipment from a German company but we design & build all the pneumatic conveyance systems in-house. These blowers are notoriously loud, and over the years we have evolved our blower designs to be more and more quiet. Some of our early designs are so loud that we've gotten noise complaints from half a mile away, and been fined for noise pollution. Every new installation has been an improvement over the previous one, with the exception of our most recent installation last month. This was supposed to be our most quiet design by far, but for some reason it is much louder than previous installations. I'm the Controls guy; I design the automation systems which align all the valves to move product from a specific origin to the a specific destination, and provide the operator a central location to start and stop all the various components, so I'm not really part if the think tank which decides why it's so loud and what to do to fix it, but I have my own theories. I believe the exhaust line going to outside is an unfortunately specific length which complements the frequency of the blower noise, amplifying it instead of attuning it. I have read about such things in my own time, while trying to learn about automotive exhaust systems. Further I believe that the outlet of the exhaust is an unfortunately specific distance away from the side of the building, causing the pressure waves to converge at the surface of the wall and vibrate the whole building, and the secondary noise of the vibrating structure adds to the primary noise of the blower.

I say all that to say this:
For your exhaust system and your compressor alike, you may need to play around with your exhaust ducting, changing the distance from the outer wall which it ends, elevation, duct size, etc. to empirically discover a solution that is actually quiet. Or read up on sound waves and exhaust systems and calculate it all. I don't know how to do that and I suspect it might take a few years of schooling to really understand, which is why I would personally choose the empirical method.

 

[GeneV]

Alright guys, was a bit of trial and error...and I also shattered the piece of plexiglass while jig-sawing a hole in it for the duct, it was gonna fit in the window. But, the extractor itself works pretty good!

So as you know, I got the 6" duct fan. Initially I thought about using a reducer from 6" to 4" downstream of the fan, to reduce the size of the duct hanging from the ceiling. I did some research on the effect of air flow, and from what I read it wouldn't have much effect. I bought extra parts to try out with both a 6" and 4" duct. What I learned was that reducing to 4" duct had a noticeable effect on sucking up fumes, you had to be much closer in. So, rolling with 6" duct.

I still gotta perfect it a little bit, which I would love to do immediately, but got to put it aside for a few days coz of other stuff I gotta get done...which SUX, I hate having to stop when I'm really into doing something! But anyways, it should be great. Rather than permanently mounting it, It's all going to be modular, and suspended from hooks in the ceiling. So when I'm not welding, I could just pop it off and break it down to a few pieces, all under a minute work.

 

[MF RED in MT]

This year the welding fumes don't bother me as much as the west coast wildfire smoke.

I use my Ryobi garage door opener fan accessory to help keep the smoke out of the garage, it helps as I only smell the smoke while outside.

KC

Ryobi Garage Fan Accessory for Garage Door Module System - GDM421 - YouTube

 

[BukitCase]

Gene, good choice staying with the 6" - the area of a 6" circle is 28 square inches, area of a 4" circle is 12.5 square inches. Necking down to 4" basically just slowed your flow rate to 44% of what it was with straight 6" run, the velocity (as you discovered) suffers. Depending on your inline fan, necking down might've ALSO shortened the life of the fan motor.

No "internet expert" here, just 33 years in industrial instrumentation preceeded by another 15 in electronics... Steve

 

[chim]

We made up 3 of these in our weld shop at work using the MonkeyArms on the end. That allowed quite a large radius of coverage:

 

[dragoneggs]

Alright guys, was a bit of trial and error...and I also shattered the piece of plexiglass while jig-sawing a hole in it for the duct, it was gonna fit in the window. But, the extractor itself works pretty good!

So as you know, I got the 6" duct fan. Initially I thought about using a reducer from 6" to 4" downstream of the fan, to reduce the size of the duct hanging from the ceiling. I did some research on the effect of air flow, and from what I read it wouldn't have much effect. I bought extra parts to try out with both a 6" and 4" duct. What I learned was that reducing to 4" duct had a noticeable effect on sucking up fumes, you had to be much closer in. So, rolling with 6" duct.

I still gotta perfect it a little bit, which I would love to do immediately, but got to put it aside for a few days coz of other stuff I gotta get done...which SUX, I hate having to stop when I'm really into doing something! But anyways, it should be great. Rather than permanently mounting it, It's all going to be modular, and suspended from hooks in the ceiling. So when I'm not welding, I could just pop it off and break it down to a few pieces, all under a minute work.

Gene, pics please of your set up when you get a chance.

 

[strantor]

Gene, good choice staying with the 6" - the area of a 6" circle is 28 square inches, area of a 4" circle is 12.5 square inches. Necking down to 4" basically just slowed your flow rate to 44% of what it was with straight 6" run, the velocity (as you discovered) suffers. Depending on your inline fan, necking down might've ALSO shortened the life of the fan motor.

No "internet expert" here, just 33 years in industrial instrumentation preceeded by another 15 in electronics... Steve

Also no expert, most of my knowledge of fluid dynamics is based on fixed displacement pumps. And that knowledge leads to me expect that when you neck a pipe down (ex from 6" to 4") the velocity will increase, not decrease. The same volume of medium flowing through a smaller pipe must flow faster in order for the volume to be the same. I guess a fan in a tube behaves differently. In my mind, volume must the variable here instead of velocity; going from 6" to 4 inches must decrease the volume by the percentage you figured, with velocity remaining constant, no? Or is the whole equation thrown out of whack by changing pipe diameter?

 

[Fallon]

Also no expert, most of my knowledge of fluid dynamics is based on fixed displacement pumps. And that knowledge leads to me expect that when you neck a pipe down (ex from 6" to 4") the velocity will increase, not decrease. The same volume of medium flowing through a smaller pipe must flow faster in order for the volume to be the same. I guess a fan in a tube behaves differently. In my mind, volume must the variable here instead of velocity; going from 6" to 4 inches must decrease the volume by the percentage you figured, with velocity remaining constant, no? Or is the whole equation thrown out of whack by changing pipe diameter?

Many fans suffer greatly when facing increased resistance. Standard computer fans loose half of their volume when going through a nozzle. A squirrel cage fan on the other hand isn't affected nearly as much.

Your right about velocity increasing if diameter decreases but CFM stays constant. But with pretty much all fans increased resistance will mean decreased CFM. Some fan types will suffer a lot more than others.

Fixed displacement pumps will increase their power usage with increased resistance, but not drop flow dramatically like a fan will.