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Discussion in 'Compressors' started by huskystafford, Jun 15, 2020.
Now you can spend the money WE have saved you on that extra airbrush you need for AAD
Come to the dark side ......
See, I'm not on my own...
I was thinking about how does high performance plus behave but...
if you bought an hp- sb+ then You would benefit from an extra Side cup for colour swapping when you use your CM-SB
anybody have experience or knowledge about this? It's silencer for air drain valve and they are dirt cheap. 2 bucks..
low silencer 2 bucks
high silencer 2 bucks
reduced silencer 10 bucks
So what is up with those silencers, are they any good?
my (limited) understanding is that these are helpful in silencing the blow off valve - that horrible loud noise you get once the tank has filled. not for when you are draining the tank. I've no experience with them.
Thank you Jackie for brainstorming. Actually that would be use full as well. I was planning to pick one of those today, but beats me, where this needs to go
To be honest I don't know where the blow off valve is, but this would be very use full if it's for blow off valve. Cause that sound is loud...
Drain valve you can always empty slowly so there is not so much noise, but blow off valve is another story.
The blow off valve is usually attached to the pressure switch that controls when/at what pressure the compressor stops filling the tank (look for a 8mm-ish copper or plastic tube feeding into the black switch box atop the compressor), as that switch is what also activates the valve. The ones I've looked at were all pin-valves though, like the valve on an auto tire, so I don't think it'd be possible to mount a filter/silencer like that onto them. They work by the plate of the pressure switch depressing the pin, and so the air that's released sprays around the pin and directly against the plate at a range of a few mm. I think that's part of the source of the loud hiss.
I've used one of those sintered brass/bronze filters on the air intake of a small tankless compressor, and it did soften the sound noticeably compared to the stock plastic-and-foam filter. I've considered trying one on the intake of my CAT compressor, but one thought bugs me. There must be a reason why they aren't normally used/aren't provided stock. They're cheap, so the cost difference shouldn't matter, and they're better at sound dampening, so I wonder if they don't filter as effectively as the fiber filters. I wouldn't want to risk the longevity of my compressor if lesser intake filtration might effect that.
Every vendor for them I've seen labels them as exhaust filters. IIRC I've never seen them sold as intake filters. Again; I wonder if there's a good reason for this.
I could well be wrong or mistaken though. I'm far from an expert, and these are questions I have, not assertions. I would love to hear from someone more technically knowledgeable.
great info Nessus.
Maybe this can share some light
just one example from this link. They have bunch of them for different purposes:
These mufflers exhaust through narrow holes on one end to provide a concentrated blast of air. Use them to eject items from your conveyor and direct exhaust away from delicate applications. They have an external hex drive so they can be tightened with a wrench.
Those are all exhaust mufflers/filters. A good selection (though I personally won't deal with McMaster Carr after a bad experience I had with them), but there's no info in the listings that addresses the questions I was wondering about.
I am confused about all of this. I have in plan to go tomorrow to a store to get some more info. I didn't have time today for it. I wonder if they know something about or they are just selling them...
Well, there's 4 places you could, in abstract, place one of these on a compressor.
Exhaust (air out):
1) Air outlet to the hose/brush/tool. That's an enclosed line, so an open-sided, non-in-line filter like this wouldn't go here. There are moisture filters like the normal in-line bottle type that use sintered brass/bronze bead media like this in place of the normal fiber/foam piece, however. That may be a good sign as to this type of media's filtration ability, or they may just be made for other compressed air applications that have different filtration needs. IDK.
2) The bleed valve. This is the bit that abruptly goes PSHHHHHHHH every time the motor shuts off after topping off the tank. Its job is to ensure neutral air pressure in the line between the motor and the tank (and thus in the motor guts) whenever the motor isn't actively running, as back pressure in the motor when it's not running can damage it. There's no way to put a muffler on these (and it doesn't need filtration), as the button that opens the valve is inside the air outlet itself (like with the air valve on a car tire) so you can't cap or enclose this air outlet without preventing the valve from operating when/how it's supposed to. Large industrial compressors may use a different valve setup/type for this, and thus might be able to use a muffler. IDK. Small household/garage ones like most of us use can't though.
3) The tank drain valve. This is the spigot at the bottom of the tank. Its job is to allow you to drain out condensed water that may have pooled in the bottom of the tank. It can also be used to vent tank pressure, but this can also be done through to tool/hose outlet. Putting a muffler/filter here would interfere with the ability to drain water through it. You could in theory install a forked manifold here so it'd split into an air drain and a water drain, each with it's own valve, and the "air" end with a muffler. Personally, I just use the tool/hose end to vent the tank air, only opening it a little so it vents slowly and quietly, and only use the tank drain valve for draining water while the tank is not pressurized. If I wanted to be able to vent FAST and quietly, I'd use a manifold with a muffler on the hose end rather than the drain valve.
Intake (air in):
There's only one of these: where outside air is sucked into the motor to be compressed. It needs a dust/particle filter to prevent airborne particles from getting into the motor where they can become "sand in the gears". Most compressors come with a fiber or foam based filter that screws onto the inlet, and also acts as a muffler (a surprising amount of compressor noise comes from the intake, not the outlets). These aren't very good mufflers though. In fact some of them can act as resonating chambers, making noise worse. These can be easily replaced with a sintered brass/bronze muffler/filter like the ones we're talking about.
In this context, a sintered muffler filter has some notable advantages: it's much more space efficient, and it works much better as a muffler. Fiber/foam filter/mufflers are probably cheaper, but also probably not by enough to meaningfully raise the MSRP of the compressor, which makes me suspicious as to why compressors aren't shipped with them instead of fiber/foam ones. There must be a good reason. The only reason I can think of (by process of elimination) is that they don't perform well enough as filters. I might be wrong though: this is just guesswork on my part.
All the sintered filter/mufflers I've seen are advertised as "exhaust" mufflers. I've never seen one labeled as an "intake" muffler. This ties into the above question about their filtration ability.
Also, these listings tend to be vague about the kind of machinery they're meant for. It's possible they're not intended for air compressors in any context, but rather for other pneumatic or combustion driven industrial machinery. IDK.
Basically what I'd want to know is:
A) what kind of specs does an intake filter for a compressor need to have (what type and size of particles does it need to reliably catch), and
B) are these sintered muffler/filters capable of meeting those specs.
If the answer to the latter is "yes", then I'd say go ahead and swap out the fiber filter on your compressor for one, regardless of why they're not put on these compressors stock (i.e. the reason is probably economic, not practical). If the answer is "no" then it's better to stick with the stock filter, unfortunately, and seek a different way to limit noise.
This is great post Nessus. Especially for somebody like me. Very well explained and noob friendly.
The tank drain valve I released very slowly this night, so I am doing this ok. according to what I read in your post. I was wondering today if I get less moisture out of tank if I release air slowly.
The bleed valve is loud The first time I heard that valve I almost *censored myself. I needed few months to get use to it.
Also I have my compressor surrounded with the pieces of box in which I got it, so it's less louder cause of that. I know it sounds weird, but it actually works quite nicely. Some very thick carton looking like a wood material.
It is much easier for me to write an answer, cause you explained all the stuff in one post
Thanks. I do try.
I dunno. A sharp pressure drop by itself shouldn't cause condensation, but a temperature drop would, and a sharp pressure drop causes a sharp temperature drop (we've all experienced a spray can getting cold in the hand, and even developing condensation, if it gets used a lot in one session). Depends on how the maths work out, and I don't know the equations, much less the variables for your (or my) compressor.
Yeah. I've head that some makes and models of bleed valve are louder or softer than others, so an aftermarket replacement might help in theory, but I couldn't tell you what brands or models to look for. Depending on the compressor layout, it might be possible to build a baffle box for just the bleed valve or pressure switch. That would be an interesting project, but would take some R&D.
Not weird at all. Building a box around a compressor is a common way to muffle it. Soft materials dampen sound, turning high frequency sound into low frequency sound (turning treble into bass, as it were). Dense materials absorb sound, turning kinetic energy into heat energy, or conducting it away into whatever solid surface it's in contact with. A cardboard box will take the edge off the noise, a box made of drywall/sheet rock, and lined with foam on the inside will all but eliminate it.
Though with a fully enclosed box heat can be an issue. People I've seen go all the way with box building usually install a cooling fan, sort of like on a computer case.
The bleed valve on my compressor is a bit sharp, but not too loud, so I can live with it. The motor, however, does produce a lot of low frequency vibration. It's OK enough in the air, but I can't put it on the floor, or it'll broadcast a loud low-frequency rumble to half the house via the wood floor beams. I found that putting it on a 12" concrete garden paver square with a bit of EVA foam floor mat between the paver and the floor (or table) eliminated both that issue and a bunch of the in-air noise.
Doesn't look like a sc fi. It got 2 pc vents, easy peasy
I went to check for california air compressors, cause I know they are quite popular in airbrush community. Either way, for claimed 40% less noise, it doesn't look special. Some metal and acoustic foam if I see correctly.