EEVblog Electronics Community Forum
General => General Technical Chat => Topic started by: Jester on January 16, 2020, 12:30:49 pm
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Not related to electronics, however there seems to be an abundance of knowledgeable people on this forum so here goes....
I recently moved and need to reinstall a smallish air compressor in the garage. I’m thinking about suspending it from the ceiling using four wire ropes one attached to each corner of the compressor that weighs about 200 lbs.
The entire garage is drywalled with no access above the ceiling. The 16 foot garage door rails are attached to the ceiling in the typical fashion using perforated L-channel that is screwed vertically into the ceiling joists.
I’m actually somewhat surprised that this is actually adequate to support a good portion of the door weight when fully up, not sure what that door weighs but it must be way more than 200lbs.
I’m thinking of finding the ceiling joists with a stud finder and then installing two sections of L-channel about 4’ long with perhaps 6, 2.5” long, #12 pan head wood screws per section.
Does this sound safe?
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Use lag bolts into the joists. I hung a 200# CRT projector over my couch in my last place. I’d be more worried about stabilizing the compressor against inadvertent bumps and upsets. Static or vibrating load of only 200# isn’t much.
From a noise perspective, consider also putting it outside under a roof or in a small shed and pipe the air in.
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The mechanical problems can be solved. But, unless you figure out some way to make the suspension elastic, your neighbors are going to come after you with the pitchforks and torches.
It will turn the whole garage into a sounding board for the compressor.
Jon
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It should be OK if the ceiling of your garage is strong enough; which is something you will have to research on your own. However the drywall ceiling may become a sounding board and amplify the noise. McMaster sells threaded rod vibration dampers that may help.
I hung a large fan in the ceiling of my attic from cables to draw out hot air and it works very well, but I had open roof joists to easily find proper attachment points.
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Using chains or belts to suspend the compressor to the joists will provide significant decoupling, reducing noise. I use this technique in my wood shop to hang a large air filter from the ceiling.
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Some suitably sized spring suspension should solve sound...
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I actually ordered and received four rubber+ spring vibration hangers from eBay, that should help. I might build a box out of 2” styrofoam if it’s still to noisy, not exactly sure how I will do that yet and will figure it out if need be.
I did some searching re mounting screws vs. Lag-bolts, my concern is splitting the joists. Home Depot sells some specialized hardened long but narrow screws that might be ideal.
Thanks for all the comments
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Pre-drill for the lag bolts and you won't split anything.
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I wouldn't use lag screws as they would tend to weaken the ceiling joists.
I would suggest getting some 1 1/2" to 2" angle iron and running lengths of it along the joists anchored with deck screws about 2 1/2" to 3" long through the drywall and into the joist spaced every 5 to 6 inches to spread the weight. A little over engineering in these types of installations doesn't hurt.
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Why not.
Hang it with a small tilt towards drainage port, so that you can get all the water out of the tank regularly.
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Why not.
Hang it with a small tilt towards drainage port, so that you can get all the water out of the tank regularly.
Great idea, I will do that
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I’m thinking of finding the ceiling joists with a stud finder and then installing two sections of L-channel about 4’ long with perhaps 6, 2.5” long, #12 pan head wood screws per section.
Use lag bolts into the joists. I hung a 200# CRT projector over my couch in my last place. I’d be more worried about stabilizing the compressor against inadvertent bumps and upsets. Static or vibrating load of only 200# isn’t much.
I wouldn't use lag screws as they would tend to weaken the ceiling joists.
I would suggest getting some 1 1/2" to 2" angle iron and running lengths of it along the joists anchored with deck screws about 2 1/2" to 3" long through the drywall and into the joist spaced every 5 to 6 inches to spread the weight. A little over engineering in these types of installations doesn't hurt.
I recently rehung my basement stairs which collapsed under me because they were *nailed* into the ceiling joist from the bottom of the joist. WTF? How could that ever pass code or inspection?
I agree with Gregg about using deck screws but get the ones which are specified for structural applications. They will have some sort of strength specification. I ended up with these (https://www.grkfasteners.com/products/r4-multi-purpose-screw).
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You didn't mention whether your compressor is a vertical or horizontal tank design. Horizontal would be better for what you are doing, but either way you might find your compressor doing some interesting dances. You will be creating a spring mass resonant system which could easily be excited by compressor frequencies. If you are unlucky and find this you can play games with changing stiffness or mass to move the resonant frequencies around. Be sure to watch during compressor start up and shut down as there may be some torque loads that move things in ways that you won't be happy with. Once you see it you can come up with solutions.
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I think you'll have a combo of all the dramas expressed by the member comments above, and some unexpected headaches later on
My neighbors are extremely VIP for me and vice-versa, we all know when to make serious noise and for how long,
and any necessary noise (grinder, drill, air tools etc) at later times, something ASAP can come up at the last minute :-[ done quickly for say one hour max, and then it's over.
fwiw occasionally I keep the door closed when the compressor is pumping and use long hoses to work outside,
or if I don't need it at the max 145 PSI, I switch it off and use it till the PSI is unusable for the application,
and then restart and repeat.
For blower duties the tank works good enough from 30 to 145 PSI, so I don't need it refilling all the time to get to 145 and driving me nuts |O
All I can add is attach a long hose to the drainage port and a valve/regulator at the end
so you can drain the crap out any time outside or in a bucket, even when the compressor is running.
Cold start ups are easier on the compressor motor and piping too, if that drainage port release valve is open for a second or two on start up, then closed.
You need a way to test the safety cutout relief valve occasionally too, remotely, a string or something to pull it briefly = never trust any compressor or anything attached, no matter the quality,
as there's no warnings when they go BANG! in your face, especially with heated, oily, aged hosing, and fittings that have worked loose or never done right from day one, be it user or manufacturer fault,
and if you get wacked real hard in the right spot with a whipped metal fitting or the rust water attacked tank finally ruptures :scared:
you and or someone close by, may not live to tell the tale.
Air Compressors are THE most dangerous tool IMHO, no matter the condition, brand rep, or how well it's serviced and checked,
it should be dealt with the attitude that TODAY is the day it will give the user 'attitude' >:D