Rotary Screw Air Compressor: What are they?! Worth the hype?
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- čas přidán 11. 06. 2016
- This video summarizes the basics of what a rotary screw air compressor is, why we bought an Atlas Copco Screw Compressor, some of their drawbacks and things you should consider if you're thinking about buying a rotary screw compressor!
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Links for this video:
Here's a GREAT, quiet air compressor for small shop or dedicated machines: amzn.to/1OkZ9q7
Thanks to Cleaveland Tool for help with the RapidAir! You can buy through them at bit.ly/1UoPLSY
Music copyrighted by John Saunders
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it's good to see people using decent gear, I just started working for a compressor company and we service and repair up to 200kw units. they are huge and produce an incredible amount of air. screw compressors are incredible machines. this one is only a baby. I took out a motor from a 70kw in the workshop and that baby needed an engine hoist!
Hell yeah. Comp tech here in CA. Air is everywhere
You want a wet tank system because the air right out of the screws is hot, the refrigerated dryer works better if it doesn't have to take the excess compression heat out before chilling the air to condense the moisture. The reason you want to try to keep the screws running as continuously as possible is because the oil separator and the oil flow thru the screws needs to stabilize for lowest oil bypass. If the air and oil are flowing through the screws at a stable level, the separator will work at its best. On startup or major disturbance of the flow, the screw can starve for oil and the separator can bypass. Hope this makes sense.
Wet tank is not needed in this compressor. The compressor comes with a build in after-cooler that eliminates majority of the moisture.
This machine has a built in aftercool system that will cool the discharge air within 10 degrees Fahrenheit, plus or minus a few, of your ambient temperature. Running through a dryer without a wet tank is a typical set up for most applications. As long as the coolers, filters, valves and thermostat are working properly and atlas copcos recommended preventative maintenance intervals are executed properly.
One other comment and this is based on my 35+ years of building refinery projects that included air systems for plant air and instrument air. For a loop as long as yours, I would recommend using a main header loop at least 2 sizes bigger than your drops to your work stations. This way you have a header system that can accommodate heavy air demand from multiple air stations. If your main header is undersized, you have negated the capability of your compressor (i.e., it cannot push the air into the system fast enough to compensate for the draw down due to pressure drop loss in the piping system).We typically use a 4" header with 2" subheaders to feed about 100 3/4" air supply points in a refinery process unit. This insures constant pressure at all the instrument stations and control valve stations. Think of it this way, if you have 15 drops on your loop and all of them get used at once, you need a reserve in the piping system itself for the compressor to fill up from the tank.You may not have heavy air demand now, but if you plan on future expansion, you might want to consider re-sizing the header loop.Regards;Ron Kluwe
Ran some quick sizing calcs for you and at about 40 CFM of draw, it looks like your current system will go to Zero PSIG at the drop end points with the header it appears you currently have (I am assuming 3/4" tubing throughout). The system is essentially choked at this flow rate as the compressor cannot push enough air into the header, no matter how big the compressor is. If you upsize to a 1.5" header for the main loop, this is only about a 3PSI drop in air pressure at 45 CFM demand and a 12 PSI drop in air pressure at 90 CFM demand. Also, typical practice is to put a large air receiver vessel after the drying system in order to limit surge demand on the compressor. For the volume of pipe in your shop, it looks like a 300 gallon air receiver will give about a 5 minute surge coverage and a 600 gallon air receiver will give about a 10 minute surge coverage. Something to think about to ensure longevity of your air system and flexibility for future expansion. I can fill you in more on this at the BarZ Summer Bash.
+NYC CNC there is a difference between pipe of a certain size and a single choke point. Your long run could benefit greatly from a diameter increase.
Put a 300 or 600 gallon receiver tank in the system and you can run your compressor all day at 20 CFM and maintain 125 PSIG at the outlet points. Even with short term demand (5 or 10 minutes at a time) to 30 CFM you can maintain about 115 PSIG at the outlets. I am very surprised that Atlas Copco would limit the output to a 1/2" outlet size. My bet is that if you look into the guts of the machine, it is the air drying system that is the limiter on flow and that they are using 1/2" tubing for that system. Might want to ask them if a 1" outlet can be installed at the compressor.
I waS thinking the same thing... thats some tiny pipe for such long runs. Especially right off the reciever tank... seeing the video more it seems like a very badly made system
My former shop system had a 15hp piston compressor in a back room and we had 3 80 gallon tanks plumbed into a 3” main line that ran the length of the building and each station dropped off that main. We had two air dryer systems. A main refrigerator dryer, and a secondary for paintwork, powder coating, and so on. We used a lot of air, rarely did it run down it worked well to maintain power tools, etc... sadly the tri piston compressor was ridiculously loud.
Beautiful shop!, first time watching your vids!
I have used and worked around a number of screw comps, 10hp to 65hp, and they are definitely a nice compressor compared to piston comps.
They are designed to use oil to help sealing of the rotors and pass a LOT of it out the discharge, and the oil separator should catch 99% of it, but a external refrigerated dryer with proper filters and traps, will give you superbly clean air!, again, not cheap, but worth it in the long run!.
The one at my old work is an Italian made 10hp unit (ABAC or some company), and the auto-drains did dump a tiny bit of oil outside the shop, but very very little. not enough to show on the sight glass between services, its literally vapor, compared to some piston comps that blurt out oily milky goop every time you drain them.
Best of luck with it!, wish I could have one at home and at work :D
I work at a tobacco facility at this time and Atlas Copco is the name of the game there having at least 20 of their bigger compressors, some even hooked in parrallel to keep up, with all the dehydrators and stuff all around the plant...At this point though there are room heat issues and they will be installing some equally extreme ventilation system in all the compressor rooms before the summer takes a toll on them!
That food grade oil really doesn’t like that heat.
GX5 as in 5KW is roughly 7HP - hence the name
Gx 5 is having 5.5kw motor power = 7.5hp
Basant ji nice reply
I work on a 240kw compressor
nightmare in action ji where ?
@@nightmareinaction629 I make the maintenance of 3 boge so340 of 250 kw from a client
When I came to a new job it was in a warehouse kind of building with high metal ceilings and it was very loud with a lot of echoing. Later on they did noise abatement by hanging cloth in vertical sections in sort of a zig zag pattern and it made a huge difference. Something to consider.
As someone who works in a field where ambient noise levels are disregarded. I like the fact you take into consideration both for hearing and safety the noise level in the shop on things that are controllable. Makes a big difference when you hear it every day.
The compressor should be in it's own room with cool air access.
The rotors are a very tight machined fit (no seals) so thermal expansion and contraction is their enemy. Compressing air makes heat so that is why you don't want a screw compressor cycling as it increases wear on the unit. I have found that one of the best things for reducing compressor noise on a piston unit is to slow the speed down. We have an 80yr old Champion 2stage 4cyl compressor at work that has been maintaining 225psi air for longer than anyone is left alive to remember. The thing only runs 400rpm which is probably why it has lasted and is one of the reasons it isn't real loud. It is probably half as loud as my 5hp Campbell Hausfield.
Your comment got cut off... How do you slow the speed down?
Change the pulley size. My CH 5CFM 30gal compressor uses the same compressor head as the 11CFM unit, but because it's a 110v compressor they run it at half the speed, produce half the CFM, and half the noise.
eformance That makes sense, thanks!
I love the older machines, my granddad's generation sure knew what they were doing....
there's a new fad about silent air compressors nowadays. one of their features is the speed is 1800rpm instead of 3600. The other feature is the cylinders and valves are large. (california air tools silent compressor for example).
I would recommend putting the recip in series with the screw, so you can run either depending on your needs. That will eliminate the screw cycling on and off. After the warranty period, you can probably get a VFD to control the motor on the screw compressor, which will be more efficient and allow for soft starts or throttling without having to cycle off. Also, an additional external oil separator will get the oil down to 1-2ppm in the service lines.
I would set them up parallel so they could be isolated from one another for maintenance
i have one the same model at work . very good unit , very fast to refill with air .
The main reason I have heard that continuous run screws are best, is because it keeps the oil hot and that prevents excess moisture buildup in it. which stands to reason, too many short cycles would make the oil milky, as it does in a car engine's cam cover if you do too many 5 min trips to the store, it's the coldest point so it goes all gloopy.
This is exactly right, although load/unload screws are fine too so long as they are sized correctly and the right size storage receiver is also used...this will keep the load cycles to a point where the heat in the machine is maintained...I generally like to see 165-185F and that keeps the moisture at a vapour so that it will pass the air/oil separator element...had a client once with a 100hp variable speed machine in place where a 30hp modulating machine was running at about 80% capacity (they got a good deal on it I was told)...and this machine normally takes 3/4 of a 20L pail of oil...was called in to see why it was constantly popping the safety relief valve each time it tried to cycle up...drained 2.5 20L pails of fluids from the machine...2 of those pails were water...this machine was running at a 'frosty' 125F peak.
We have a couple Ingersoll Rand Rotary Screw compressors. A 20 HP and 7.5HP one. We're in the food industry and so it's powering our 14 bucket scales, bagging machines, metal detectors and other things. There's a lot to do to maintain them. There's no computers in mine and are around 18 years old now. The 7.5HP is backup, but it doesn't keep up with our air needs. We also have a Air dryer our air goes through.
Aussie50 i
I wonder if that could be solved with an oil pre-heating system of sort.
@@FrozenHaxor they have a thermo stat on them so it would help only a bit. the best is to load them up and work em like they are designed.
Should have considered a Kaeser SM10. Has about the same capacity tank, but has a built in refrigerator drier, built in oil separator. Also has the computer built into it. We run print finishing machines with it and it’s programmed to run the motor continuously, but only compresses between 115-125. Love it!
Kaeser is a very solid brand. We have at work Copco's and Kaesers and Kaesers have been superior in reliability.
If the sole reason you're bummed about not having a computer on board the compressor is due to the shutoff timer, you could always install an off delay relay in the control circuit to extend the run time beyond the signal provided by the pressure switch. Couple that with either a solenoid actuated relief valve in the same circuit or even a mechanical pressure relief valve to handle the tank overpressuring issue, and you've accomplished the same thing.
Thanks John for the very informative Air Compressor video!
As far as monitoring your machines. installing cameras in your machines might be useful. Either a multicamera analog security system, or a set of IP cameras permanently mounted in your machines. You could just add a secondary monitor in your office with a split view for each machine. Perhaps even remote e-stop buttons in your office so you can stop a machine if you spot a problem with out have to run across the room.
I run out of my garage with a fadal 4020 so quiet operation is important to me. I looked real hard at the Kaesers when I started up. But in the end I couldn't justify the expense and went with a large two stage piston pump. It's not too loud and doesn't run that often. I did have to build in a poor man's dryer which consists of about 40 ft of copper pipe to cool the air before a drain valve and a water separator. But it works so well that nearly all the water that exits the pump comes out of the drain. Almost nothing makes it to the separator. If my shop was as large as John's I wouldn't hesitate to put a screw pump in though.
Great video as always. For the home shop cheap version of the rotary screw compressor people may want to look at the quiet compressors from California Air Tools. They make 1 HP and 2 HP compressors that are about as loud as a laser printer - unbelievably quieter than the Porter-Cable pancake compressor I had before. It's possible to use one of these per machine and avoid the airline runs and they are very cheap to buy on Amazon. That gives me some redundancy too. It's great to have a quiet shop!
Two of the Machine shops I have worked in so far have had the compressors located in their own little shacks outside. This is how I will probably do it as well. You can remote a starter switch or button inside as well.
Excellent video and beautiful shop!
I always learn so much from the way you explain things John..really appriecate your veiw an all the research you do..thanks
Didn't even know they made such a thing as a screw air compressor! lol learn something new every time I watch your channel John. Thanks and Happy Holidays to you and your team and family!
Thanks, You talked me out of looking into one. I buried my 5 HP 2 stage IR in the back corner of the shop behind some storage shelves. This keeps it quiet enough for me. I might try to pipe the intake outside also. Just need to keep the critters out of the intake tube.
We had several of these running in reverse, vacuum screws to operate the HP electronic board testing fixtures. They can really suck in vac configuration. The noise is the only benefit, and they do like to run continually. This was the secret of the U-boats, these screw style compressors were so quiet that it was extremely hard to track the U-boats by underwater electric running sound. The oil has to be special anti foaming screw compressor (super charger) oil, very pricey stuff. Good video. 3 phase fire pumps have a phase alarm on them to prevent the pump from running backwards.
I have my piston compressor hanging on thin ropes and it makes less noise now.
The ropes are elastic and absorb vibrations.
Awesome video, awesome shop setup, and awesome dog! I had Vizslas growing up and now that I live in an apartment I can no longer have Vizslas, or a shop.
Proud of being an intern at Atlas Copco :D
Love your explanations and your insight on this system you just installed. Thank you for sharing this!
can you invest in a tripod or longer arms?
Heh Heh...Kind of annoying eh? In your face like a Close Talker.
I just watch him on the small screen.
Dylan T lol...good machinist, but he tries to talk past his lungs air capacity which causes him to grab for a mouthful of air....:)
Watching your videos makes me sea sick, great information but the constant motion of traditionally stationary background scenery is pretty hard on the viewer.
Well, the reason video makers become popular is that they aren't awful to watch, or they ARE awful to watch, and that's their shtick. This guy is accidentally awful to watch, because despite people giving him pointers on being less awful, it gets disregarded and he keeps being awful. At the moment, his face-cam videos are cringe-worthy to the point of being unwatchable because of exactly the above mentioned reasons. He's stated repeatedly that he is working towards a larger viewer-base and constructive critiquing is how that happens.
Bottom line is, better videos are BETTER, and he should really try to aim for better, as his filmography is the biggest letdown in his videos.
Aside from the Tormach machines... Hell, even HAAS is worlds better...
Brad Gefroh because the content you have posted is worlds better right? You keyboard warriors need a new hobby seriously.
Hi John, great video! Wondering, have you maxed out the capacity of this compressor with the addition of new machinery? Thanks in advance, and thank you for all the manufacturing tips and resources you provide!
Good info. I never even thought of 'stale' air in the lines but that would make sense that you would get a dead spot with water build up. I think leaving on the pallet is a great idea, super easy to move if you need to repair something on it or just paint the wall behind it!
I double action compressor is more efficient than a screw but these tend to be really big, over 30 HP, monsters. Even a single action 2 stage compressor is still going to be at least as efficient as a screw. But the biggest, by far reason to run an air screw is duty cycle and life span. Air screws, buy nature, run a 100% duty cycle and last for many years (at least a decade). If you ran a piston air compressor at a 100% duty cycle it would be worn out very quickly, you need to keep them under about 60%. Even then you really are only going to get maybe 15,000 hours out of one before it's worn out. Compared to about 100,000 hours or so life on a screw it 'should' be cheaper to own as it has very little maintenance and will out last many piston compressors.
Hey John very helpful vids.. do you know if there's a way to hook up mach3/4 to arduino mega, uno or nano?
Haha I made the same condensation catcher. I ended up using a evaporator cooler filter inside the bucket to make it even quieter. Now the air leaving the tank makes more noise than the air leaving the tube. :) Great video's always enjoy watching! BTW I have a Eaton PolarAir compressor (7.5Hp) has a oil pre heater, air dyer/filter, computer and auto drain, plus those guys have been great to deal with.
The other nice thing about having a loop is that you can isolate any small section for maintenance or to make changes without cutting off the downstream part of your system.
Our screw compressor does both, either suction-off-loader or shuts down when it gets bored. I love the ring main idea. I run some buffer tanks, but the main tank is huge as well. With varying air loads you can only have a best compromise. Thanks for the vid :o)
Looks like a great job on the air system. There are phase meters so you know before you switch on if the rotation is correct. But it can be hit and miss with how import motors are wound and labeled. I just know that every time I hook up a 3 phase motor, it will be always running backwards. And now that I got a meter, I haven't had a chance to use it. On larger screw compressors they can also be driven with a variable frequency drive, so they run at just the speed needed to keep up with air demand and can run constantly, eliminating the starting and stopping.
Yeah, a small shop's air usage is all over the map. Sometimes nothing for hours, then practically everything on at once. No way to average that.
I wanna know does it work directly without extra tank? I wanna use it for car interior
Hi John this is the type of equipment I connect automated controls to for Seimens technologies if you look on your air compressor it may have a RS485 or a Back Net connection on it if so you can install a Back Net / RS485 Management Module to connect to your Computer , just thought I would pass that on to you
I like this video a lot. It shows you did your research and I think it shows the progression of learning air compressors. Well done sir.
Is your screw compressor belt driven?
I know on our one you could set manually set the "dwell" time.. this means less starting up.
I have nothing like Your wonderful system (Mine are 2-80 gal tanks with one two stage compressor) but I am so glad I ran a loop too for various reasons. Very,very nice shop and congratulations for apparently doing so well. Dig the American flag in the shop !
My answer to air compressor noise is to oversize the motor a whole bunch. Put a 3hp motor on your 1.5hp compressor and it'll be a lot quieter as there is more torque to drive through top dead center and it "knocks" a lot less.
a larger engine would surly make more noise...
electric "engines" are rather quiet
Greg Collins No.
Why not do this?
czcams.com/video/zIQ_AM3bnwo/video.html
Ave three phase air compressorb
I've got a gx4 in my "hobby shop and i love it. I use a 1500 liter tank so that the compressor runs for a good while every time i use it
I have never had any problem with it being too big. :)
Its like i can get away with jobs sligtly too big for the compressor because of the buffer.
My dryer is between the compressor and the tank. My own idéa, I figgured hot air would dry better because of the bigger difference in temperature. I don't know if I did it right:)
Congratulations, machine is awesome and the air plumbing system looks great too. Hope you get many many years of happy use of them.
Gonna be getting a Kaeser for my new shop, you're not joking about the price but I've had experience with them in previous jobs and they really are quiet. Thanks for talking about the distribution plumbing - I'm used to working with black iron pipe, gonna have to look at that RapidAir stuff for drops though.
That thing is great. If you have problems with noise you could consider acoustic plates on the inner roof, makes the sound bounce 3-4 times before it comes down again.
What size (diameter) RapidAir line did you select?
passive air dryers don't work well with hot compressed air, the air has to cool and the water condense out before the dryer can separate it. Big systems use refrigeration to cool the air rapidly.
true , my home compressor has a refrigerated dryer and even hooked straight at the output of the compressor it gets all the moisture out
Great great great great great video and info. Thank you so much.
Great setup! It is really quiet.
Could you tell me why does in screw compressors higher speed means less pressure and vice versa?
On your shop noise question ... hard flat surfaces reflect sound very well. Soft or irregular surfaces absorb or deflect sound. That's why commercial office buildings have acoustic tile ceilings, carpet floors, and soft cubical walls. I have also seen individual panels placed in an otherwise hard room, to help mitigate some of the sound. Even cars and vans use carpet and padding to dissipate sound.
You could could use free-standing fire resistant acoustic tiles to form baffles around and over your equipment. Air will still flow well, and you can have plenty of space to walk through, but the noise level from other equipment would drop dramatically.
I've even seen bed egg-crate foam used as sound dampers. It's not pretty, and probably not up to code, but it works for cheap. You could use some to test the idea.
You'd want to talk to someone local about doing it, to make sure you meet all local fire codes.
As a person with tinnitus from hearing too much noise for too long, I wish I knew it was a fixable problem back then.
I have a Quincy QP 7.5 that is an awesome machine but in a quiet shop it is LOUD. One thing I added to the system is a safety check valve right on the compressor output. It's a valve that will automatically close if a line or drop fails or more precisely a large pressure differential is sensed in the valve itself. Works similar to an electrical circuit breaker. It's peace of mind against having a flailing whip at pressure and having to run to a ball valve in a panic.
I have a 5hp Quincy, QT I believe. Love it. In my shop which is 30x32 open floor space, when the compressor kicks on, I can still hold a conversation within 10 feet of it. The pump is rated at 18cfm but it keeps up with my blast cabinet up to 120psi. I've never seen so much as a speck of oil come out of the tank, and I only get water when I'm running it hard for a while, like running the blast cabinet for more than 30 minutes. I can run a die grinder until it's frosty without any water issues. It runs slower than other compressors, and I do get valve noise, but it's not objectionable at all, and anyone older than 50 that wanders into my shop says it sounds like the old gas station air compressors.
Just bought a KAESER for my new CNCs. Very useful video
Looks like a nice compressor. We had one about twice that size. I recommend venting the heat directly outside if you go any bigger than what you’ve got. Also keep an eye on that air drying system, they are a pain in the ass once they start to have problems. Also keep an eye at the outlet nearest the lowest point in your system that’s were water will typically collect if you have a problem, and boy does that stuff smell bad!
Did you use the rigid pipe or the semi rigid pipe ? if you did use the rigid how did you make your radius bends in the corners and also in your drops ?
I just bought a ga30 ff from a auction it was being used in a big fabrication shop, I'm trying to find out what it's worth??
Part of the reason why the screws like to run continuously is to keep the moisture boiled out of the coolant. The oil acts as a seal filling in the gap between the screws, so they don't actually touch. Also in the book for my 5hp IR screw they make mention of the starts and stops over heating the motor. Says if more than 8 starts an hour then turn switch to run continuously. One thing about the oil maintenance is that service intervals are quite high, 5-8k hours
the sweeping bends are nice because psi is lost if volume cannot move smooth I had to learn all this because of my device.
There a compressor type that can handle higher temperatures? I need to compress a gas to around 600F, is this possible?
What kind of stuff you doing in your shop there? How many cfm the screw produce? The old polar is good, 30 cfm right? Did you need more?
Thanks. Very useful info on screw compressors. Love your vids
Also, curious, does your state require a "Pressure Vessel" permit? California does when the tank is above a certain size and pressure (yours would be, plus you have employees). It's a $150 fee for 5 years at which the state comes out and inspects and verifies the tank is viable.
Great Video! :-) Well Done
Hi John A good reason for a motor not starting and stopping often is "hi current draw on start up and heat generated from start up. A motor will have a heat rating and will generate extra heat on start up this heat is usually dissipated while running.
its the same as my ABAC compressor :-) great compressors. Oh and i love your Hungarian viszla i have 2 :-)
HOLY COW!!! technology in Zanesville.....how did that happen? born and raised there...even went to vocational school there FOR machine shop back when it was MAJVS. retired A.F. machinist and welder. good luck in the Y-city.
Is there a check valve in line by that tee? You said air gets forced around if using air in that room so air dont get stale.
What size fast pipe did you use?
thanks for sharing
You said 600'... lol. In our smallest shops ( manufacturimg and maintenance... ) we have over 600 DROPS, 200 - 220 operators, mechanics, technicians, fabricators, etcetera. All done in " screw pipe "... ASTM carbon steel pipe... that smallest building is over 1,800 feet long and 500 +/_ feet wide with numerous compressors. Even doing my proof house/prototype shop in town... was a pain in the pin feathers!
I will say, yours turned out like you designed it... and is functional and sanitary!
KUDO'S my friend, I realize this was shot 7 years ago... but still deserves a " pat on the back "!
Respectfully, Seth
Very nice compressor! Something to think about with any major addition is not so much the cost of the equipment, but more setup and future costs. You live in Ohio so there are probably at least 6 months where you need to supplement your heating(where the heat from your equipment isn't quite enough to be comfortable). I'm in FL and in planning my 1300sf shop, I have decided to keep my compressor outside under a lean to type shelter. I can't wait to work in the AC, but to avoid huge electric bills, I want to keep as much heat outside. Most people don't take into account that when they are in a cold climate, their 7.5hp compressor doubles as a 5KW heater. In FL where the AC is on 11 months out of the year, every watt used by equipment must be matched by at least a 1/2 watt to fight against the heat. That said, I don't think I could put a $10K air compressor outside. Over the life of my compressor the biggest cost will be the power to run it. If I had an awesome compressor like yours, I would need to get 20,000 hours(4KW@$.125kw/h) out of it to have the power bill equal the electric bill. Just something for those in warm climates to consider- The cost of keeping inside where it takes up expensive climate controled space. Those in warm climates need to keep things like this in mind- Might be time for a video on how to setup your plasma cutter so that the water in the water table is transfered outside after cutting.
Great video. You forgot to mention who shouldn't use a rotary compressor.
You did a great job on that pipe. I have the same stuff in my MUCH smaller shop and I had a hard time getting it straightened. Yours looks great and nice and clean.
That piping system is sweet and user-friendly but im a fan of upunor or copper
Hi John
Great Video.
All I know is most Oilless type compressors will not stand up if they are used more than just blowing up a bicycle tire once in a while. If you have a Bead Blast Cabinet/Sand Blaster they will not last very long. Oilless units have plastic pistons/parts and cannot stand the heat of higher usage like what is required running the above equipment.
Cheers
Willy
the reason to why some screwcompressors keeps running in idle is to protect the electrical motor from to many start and stops. it's decided from the manufacturer of the motor how many times that you can start the motor during a certain period of time
Do u know that period of time which is decided by the manufacturer to protect the electric motor?
In my previous job, they had 3 compressor,
2 working a fixed speed but only one working at a time as the other was used as a backup. And the maintenance service was alternating there use to level out the wear.
And a third with variable speed compressor ($$$) which was used to compensate the variation of pressure in the air grid (with the help of air tanks scatered around the factory)
Not sure if the tech is the same, but if you want a smaller quiet compressor, the Californian Air Tools compressors are the the most quiet compressors I have ever heard. I bought a small one strictly for my indoor lab. I have a 8 gallon piston compressor for outdoor work, but this little 1 gallon CAT compressor is perfect for indoors. Oil-less too.
When you said "my wife caught me taking it home..." I was about to start the popcorn.
Hi John, I'm looking for a compressor and came across your informative video. How is your compressor working out after 5 years? Did you have any issues with it?
Great video. I wish the first apprenticeship I had was as good a shop as yours appears to be.
@ 7:41 on our Atlas Copco ZR900's we have bekomat auto valves- might like to look into those =)
The 'Screaming Lena" rotary screw compressor the Huckleberry RR had was a Army government surplus unit. It had a Cummins diesel and would just sit and idle until we started using air then it would 'load' or reve up. We could use a 1" air impact wrench and it wouldn't load. This was at 90 psi.
DO NOT skeemp on air filters. I might add another filter to the intake.
Which compressor is best for fast compressing ( piston type or screw type)
Screw type, screw compressor are made because its produce a massive air flow ( cfm ) , can run continously and much quiter, but the price cant be cheap though. And also less maintainance
How much did you buy the new screw compressor?
Mine doesn't have a computer but i can adjust the time that it runs after the tank reaches pressure. Mine is an IR unit.
the reason for running is that these units are contact cooled, that is that the coolant/oil is in contact with the screws and it also collects and holds on to water. The water can only come out when the coolant reaches a high temperature.
We skip the oil sampling and keep the warranty by having the mfg perform the PM services, which are about the same cost, just under 1,100 in the seattle, wa area
John, They can't legally insist on using their oil in order to maintain the warranty. It actually breaks US monopoly law. The reason I know this is because my wife and I run an Amsoil business, and Amsoil sued a company because that was written in their owners manual. Amsoil won their case and subsequently all owners manuals since that court case were changed and now say "use Harley Davidson oil or an equivalent".
I am going guess that case was against either H-D or some luxury car company.
The problem would be finding an "equivalent" If they dont have a spec on their oil or no one makes an equivalent then your screwed...
horseshoe28016 yup
+Billy T I know H-D really pushes their Syn3 oil.
I ran Amsoil in my 2010 FLHX (Street Glide) for a while. Only reason I switched is, the shop was open the same hours I was working. That made it difficult for me to get. So I started running Castrol V-Twin synthetic. Both seem like good oils.
+Billy T actually I have also seen Amsoil in one H-D shop a while back.
Do you think there would be any merit in going with a piston compressor, but building an acoustic enclosure for it?
A lot of people do this. But watch the air temp inside as it can heat up and be detrimental to your compressor. I ended up buying a quieter compressor instead.
Put a inlet ventilation fan, and outlet ventilation fan, they need to be high flow ventilation fan. Put 6 total of them, three inlet, and three outlet.
Short cycles are hard on them for a couple reasons. One - its a lot of mass and they don't have a vfd or a soft start and the shafts and coupling takes a beating. Also the contacts are prone to arc and suffer wear every cycle.
Also since the air is compressed progressively in the screw it is likely to experience condensation inside the screw as the rotors cool.
We got two of them1 have to add oil to every week and the other one I hardly ever have to add oil to
I am not a air systems expert just someone who has used them. From my experience a good piston compressor with a large storage tank with a drier or have a second storage tank for continuous capacity for somewhat intermittent use would be a more cost effective system than the rotary screw system. The rotary screw will put out a lot of air but is really meant for continuous use. Its my take. I worked where we used 400 psi and 150 psi with regulators for lower pressure as needed. There was a compressor building that housed the air compressors and heat exchangers separate from the main building because it was noisy around that building.
How to choose a right size air compressor for an industry?. Could anyone tell me? ..
I guess the 5 in GX5 is due to the electric motor being 5.5 kW which is a more logical naming for something that runs on electricity, and does not have an ICE on it :)
What is ICE?
Internal combustion engine
Great info! Why not build a utility room with some good heavy block and concrete to house the compressors?
Outside piston compressor?
Just curious why you didn't go for an Eaton Rotary Screw Compressor? They make them and they are exceptional.
It costs more energy to start a part moving from a stopped state than it does to speed up a moving part that is already in motion (newton's law kinda deal)
also, if the screws are stopped, unless there is 0 backlash withing the drive gears, when you start it back up, they will reengage, and this can cause wear.
Or at least that would be my thinking on the start-stop issue you mentioned.
We have a 25hp screw compressor and a 40hp screw type vacuum pump. Both are over 20 years old. Neither has the computer VSD system but both go into stand-by (unloading the compressor section but continuing the motor running) when they reach set point. If demand lowers the tank pressure the stand-by valve closes and the compressing of the air begins again. There is a good electrical reason to do that. Motors pull a lot of power on start up all of which turns into heat in the motor. The second thing is there is an additional stress in the drive system from the impact of the big motors starting. If your electric company bills on a peak loading "demand meter" you may pay more for your power. Not an issue for a small motor like the 7.5 hp one you bought but... A screw system is ideally suited to a more continuous use shop than a piston type. Piston compressors get really hot if they run continuously. Not good for the oil, valves or motor. We service out machines rather than having a dealer do it. But it is still expensive. Every 6000 hours the separator element, oil filter, intake filters and synthetic oil will need to be changed. Check the costs of that before you buy, it may be shocking. We buy Mobile brand oil from an industrial distributor, much cheaper than the re-branded compressor company stuff. Our summers get hot so we have a separate air to air cooler between the compressor and the refrigerated drier. Our compressor has its own room to cut the noise, with lots of air circulation . The vacuum is in an out side shed with a big thermostatically controlled fan for summer and a heater for winter. You don't want a screw to start against cold oil. All of our piping slopes to drain points and all drops come off the top of the piping. It is also on a loop system that has ball valves that can isolate sections if needed. If I were start over, I'd have a separate room for compressors, vacuum pumps, driers, tanks, manifolds, filters, oil etc....... I'd also put in additional air tanks at the far end of the shop to even out peak flow. Again, plan ahead!
The aluminum pipe is nice, cheaper than our copper. Some people use Pex but there can be issues with deterioration caused by the additives in some compressor oils.
You may want to install an oil separator for the condensate drain to comply with regulations.
Having a back up compressor is always a good idea. We kept one of our old 10hp piston ones (over hauled) as a backup. Won't run the entire shop but will keep at least two machines running. If I was starting over I'd install two 15 hp screws with the simple timed unload system and both operated on an alternator, shifting between units on every start up. It would supply more air for peak loading and operate smaller motors at other times reducing electrical costs and demand charges. We have maxed out our 800 amp service so reducing the # & size of motors that need to start at one time might keep from having a very expensive power up grade. I wish now that I would have started with a 480 volt system. Now we have an assortment of step up transformers that waste power. Never expected to expand this much, plan ahead. This was a long post but it may help others avoid some of my mistakes.
Really enjoy your videos since I discovered them a little while back.
Did you consider a scroll compressor? (Did you know about them?)
Price point is similar to screw compressor, perhaps a bit lower now that there are NC tools to machine the scrolls accurately; even in China. ;-)
Some types are oil-less on the air side. i.e. oil has no chance to mix with the air being delivered. Quite popular in the food processing and medical application areas
They are also more efficient than screw and piston compressors. Compressed air is already a very inefficient way to transmit power - something to keep in mind if you employ lots of air tools. Air tools are neat; they are small and light but an air motor needs (IIRC correctly) about 3 times as much power at the compressor.
As for your noise problem, you can, if they're not going to be in the way of gantries, hang "soft" timber panels vertically from the rafters. Compressed fibre timber (MDF-like) is relatively cheap. I wouldn't use anything less than half an inch thick because it is too flexible and prone to tearing.
Proper noise attenuating panels are made from dense polymer foam but I hesitate to recommend those in a place where hot metal flies through the air.
Suspend the panels loosely with wire cables through reinforced eyelets. I'm _guessing_ from the videos that 4 ft by 8 ft panels could be suspended "on edge" with their bottom about 10 ft off the floor (lower and closer to the noise sources is better, but you have to keep lighting and the ability to move stuff on the floor in mind). Hang the panels at "random" angles to form a labyrinth through which sound won't travel directly. Try to avoid parallel panel faces in a direct line.
The panels work in several ways; first they absorb some of the sound energy; second they lengthen the path of sound between the source and the listener and thirdly; they set up interference between sound waves as they reflect from unequal distances.
And, if it's good enough for the Sydney Opera house; hang some panels off-vertical above areas where lots of noise is made from tools that are moved around a lot; like a fabrication floor. This will reduce the amount of sound that reaches the roof. Talk to an electrician about the possibility of incorporating lights in such panels to negate the shading of the fixed lighting that they produce.
You could paint the panels in bright colours to seal their surface but keep the finish rough and "soft". Lighter colours will minimise the amount of light that the panels "steal". If you have far too much time on your hands, you can use a router to cut patterns in thicker panels to break up the smooth surface before painting. Grooves, stipples, etc will more effectively attenuate the higher frequency noise. There are also some tricks that can be played with small holes but manually drilling thousands of them will not be fun; not even to watch.
BTW: your walls will also be reflecting sound. Make up some mobile sound screens to place around areas where work happens sometimes and where a permanent screen is impractical. It's better for the noise to hit a "soft" screen than a hard wall.
P.S. Get yourself a sound level meter and some instruction on how to use it well. You wouldn't cut metal without measuring it first; and the same goes for cutting sound. No need to spend even hundreds of dollars. Apps for mobile devices are at best of marginal utility. They tend not to be very repeatable form one day to the next.
Acoustic specialist spend big on spectrum analysers, etc. but a fundamental understanding of sound, listening and measuring can achieve worthwhile noise reduction at a fraction of the cost.
As I understand it, for one or another reason the sound waves tend to cluster in the corners, so sound damping in the corners is by far the mot efficient strategy.
Transair has these special clamps for drops. The clamps looks like it's coming straight down but the clamp actually gets the air from the top of the pipe.
I have used both pump and screws off and on for years. One thing screws have on a pump is the time it takes to catch up under heavy use. The cfm rating on the screw is much higher for sure. someone mentioned about the start up, it does take more power to start than just an idle from the screw. Which is a no load situation. In your situation it sounds like you don't really have a need for large comsumption of air but some day you may and you will be set. Its not really fair to compare the two units because the screw has some things on it that the pump will need under heavy use, like the drier. Prices on those units are up there too. And by the way the driers run all the time too. You have a nice compressor and will for many years to come. I think its worth the extra for sure.
My 15hp Abac Genesis is being wired up today. This video made me sure to check out the manual on rotation direction, it turns out there is a phase sequence relay in the panel which will indicate if the phase direction is correct and I assume also prevent operation if it is not. The manual states that even a few seconds in the wrong direction can cause damage, that might just be to scare the reader or could relate to the specifics of that design. Anyway your video came at just the right time, thanks.