Rotary Screw Air Compressor: What are they?! Worth the hype?
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- Опубликовано: 7 сен 2024
- 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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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.
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.
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.
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.
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.
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
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.
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
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
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.
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).
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.
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.
Proud of being an intern at Atlas Copco :D
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?
ruclips.net/video/zIQ_AM3bnwo/видео.html
Ave three phase air compressorb
I did not even know these things existed till tonight!
We have a screw compressor where I work and it is quieter than our old piston compressors. But not quiet enough. Our screw compressor is outside of the main building in a dedicated shed here in Florida. Its Way quieter! My piston compressor at my home shop is also in a dedicated shed separate from my shop and it's perfect! I can still hear it in case something goes wrong and I know when it's running , But it's not assaulting my eardrums.
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
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
You can quiet your piston compressor significantly by installing a rubber hose as the only air intake to the filter housing. Some experimentation may be required in diameter, material, and length.
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.
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.
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.
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.
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.
I have been using German screw compressor 10 HP since 2010 and its really great.first of all its way quieter than those piston ones (when I hear them now they feel like someone is hammering on my head or if you remember those annoying woody wood pecker cartoons). and I think mine is quieter than yours too.They definetly save me ton of money in long run as I have attached a (30 inch diameter and 10 feet tall) tank (which I made in my own shop) to it as it didn't came with a tank. I only have to fill it once or twice a day and I only need to run it for 10 to 15 minuts. I am running it on its full capacity that is 8 bar pressure.I am using air for plasma cutter, air tools(drills, screw drivers, grinders for small work etc), CNC, and paint jobs.it definitely gives out some oil in the air that is why I keep my tank filled almost all times so that the moisture and oil settles down, and the auto float ball on the bottom of my tank can expel it and I get crisp and clean air for all my tools.I would definitely suggest people to buy this if they need ton of air all day long if not then cheapest is to go with piston compressor.
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.
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.
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?
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 one the same model at work . very good unit , very fast to refill with air .
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!
The CNC shop next to mine (I use their air because I really only need it for paint guns and air sanders) just bought a new screw compressor because the old one died... it had low oil level and the guy who came to fix it said the wrong oil was used. He said screw compressor starts at 10HP, but it has a computer that basically keeps it on at slower speed bypass mode and it basically maintains about 7 bars at all times. The unit is also smaller and lighter compared to a normal compressor. The box for a silent normal compressor (basically a belt drive compressor inside a sound proof cabinet) was twice the size of a screw compressor of the same size. This can present a problem however as it takes 2 people to carry it and theft is a problem...
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.
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.
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.
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.
The after run on a screw compressor is so that the oil can cool. What happens is once pressure is reached in the tank the check valve in the screw housing opens and the return cooled oil floods the bottom of the screw vanes in the sump. If the compressor stops the oil would boil due to the generated heat of the hot oil on a stopped screw, under the circumstances the hot or superheated oil may also pose a fire hazard or cause varnish build up on the screw rotors and this wouldn't be good so cooled oil has to flood the bottom of the rotating screws.
Don't worry too much about running the motors beyond target pressure. If you get your hysteresis right, you can achieve the same result. Particularly if you can tolerate a lower switch-on pressure. I would assume that is possible in your shop. That is more efficient than pumping compressed air into the atmosphere to avoid motor restart.
There key issue with screw compressors is the maintenance of the bearing. When they fail it typically has devastating effects on the screws and/or the housing. Analog to a failing timing belt in a car. Make sure you don’t miss intervals on those. In a
proper setup, the motors starts are of less relevance to wear.
Lubrication is the one thing. Bearings wear and tolerances develop out of specification over time. You’d change a timing belt before it actually tears - I’d handle the four (or so) bearings guiding the screws in the same manner. Presentative exchange within the maintenance guide of the manufacture should be sufficient and don’t cheap out with bearings.
Why are bearings (and clean air/air filters) crucial? The two screws are precisely machined to just not touch each other. 2 to 5 thou distance would be a typical distance, the housing of the screws is a similarly tight fit. I have seen compressors being lapped in with die as you would e.g. with dove tails. If the bearings wear and therefore the screws have a tiny bit of room to rattle they will start touching and start wearing off at some points hence slowly running the precision parts.
Same effects from dirt that gets sucked into the screws and gets crushed between the screws. That introduces all sorts of problems from marring the screws to adding load to the axial guidance / bearing, collecting in the bearings and adding to their wear and so forth. Keeping your bearing happy and dirt out is key for a long compressor life.
There are also regular gears that time the screws relative to each other. Those might also wear. To my experience that isn’t a key factor. That would be analogue to the breaks in a car - the pads needs more maintenance than the rotors - which wears over use but hopefully lasts much longer. The lifespan of those gears depends greatly on the machine type and there is no “latent” issue. When changing the bearings you have to realign the screws. When this process shows too much play in your
gear, change them.
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.
When you said "my wife caught me taking it home..." I was about to start the popcorn.
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)
The reason an induction motor need to be constantly running is to prevent hard starts and stops (wear and tear). Every time an induction motor starts, a draw of the amps increasing draws on the meter. So, in commercial usage letting induction motors continually run is cheaper than having the motor turn on and off. Same principle on A/C chiller systems to cool large buildings.
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.
I have my piston compressor hanging on thin ropes and it makes less noise now.
The ropes are elastic and absorb vibrations.
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.
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.
You should have gone for larger pipe work, it’s a receiver and you’ll get less pressure drops and your compressor will stay off longer once it’s full. You should also have a bigger differential on the pressure switch if you want the machine to run on and time out. Larger Atlas Copco compressor over 160kw have only three starts per hour so run on time is long, it’s all to do with constantly stopping and starting the motor as it’s more efficient to keep the motor running than going through the star delta start cycle plus there’s less wear and tear on the contacts. . You should have gone for a GX model around 3kw as they switch off when pressure is reached and only start when the pressure switch is activated
Buying a screw compressor was one of the best things I have ever done. Our shop used a 10hp 2-stage 4 cylinder 120 gallon compressor for years. Before our CNC machines the compressor would only go on about 8x a day for about 3.5 minutes each time.
After the CNCs arrived it ran almost 50% of the time. Every 2.5 minutes the compressor would go on for 3.5 minutes.The noise was taking a toll. It was bad. It was worse than bad. (this in a shop of 2500 square feet... and no, there's nowhere to put the thing outside).
So, just for employee and the bosses sanity we bought a 10hp Kaeser AirCenter with the air dryer (it's a dry tank). Now I don't feel the compressor through the floor in the office or interrupting any conversations in the shop.
YES! They are expensive. YES! They have limitations but can sanity and hearing are worth more than a bunch of dollars.
The compressor discharges to the tank first to help remove some of the heat from compression. It also helps to remove water and residual oil / coolant. This takes the load off of the refrigerant dyer and helps to prevent fouling of the heat transfer surfaces in the dryer. The oil is also the coolant in rotary screw compressors, which is important to note. Unless the compressor has a valve to load and unload the compressor to keep it running, then it is just an on / off machine. More expensive compressors can modulate their output to maintain a specified pressure or can slow the motor to do the same. Do not put a VFD on this unless approved by the manufacturer because motor failure or sometimes blowback can occur (oil coming out of the intake filter).Maintenance of a rotary screw compressor can be high. Use OEM parts. Use of a cheaper substitute can really mess things up. For instance, the hydraulic hoses on the compressor are designed to handle the oil and the temperature during operation. Use of just a regular hydraulic hose can cause the rubber inside the hose to come off fouling the whole lubrication / coolant system up. This is a very costly repair.
I'm only halfway through the video and out of time to finish it right now, but in case anyone looking to make a purchase of this size is reading comments to learn more I wanted to mention that both manufacturers and dealers have reps who will come check out your operation and talk to you about your needs and make specific recommendations. Establishing that relationship up front is ideal for the long-term. Some will even bring and install a demo unit for a week so you can see how you like it. This is true of many kinds of shop equipment.
Bottom line: it doesn't always make sense to try to do all of your own research alone.
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.
I once worked at a wood shop that used a rotary for their compressed air. When I started work there we occupied 30,000 sq. ft. We added on a 60,000 sq. ft. addition for a total of 90,000 sq. ft. total and that rotary had no problem delivering all the air we needed for spray booths, pneumatic tools, etc. - etc. I worked there for about 2 1/2 years and the place ran around the clock 7 days a week using 2 twelve hour shifts. The only time that rotary shut down was for normal preventive maintenance - it never broke down once during those 2 1/2 years I worked there.
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
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
@NYC CNC it is actually a good naming scheme. GX5 is because it is a 5KW motor. Most Atlas Copco compressors work this way. GA11 = 11KW motor
Also the computers are fitted to the next GA range and is called an Elektronikon. Reason compressors dont like too many stop/starts is because during start up they draw a high current to get the motor going. This causes the windings to heat up inside the motor causing them to short and blow the motor if it starts too many times. This unit will be limited to 240 starts per day and as you go to higher power motors this reduces. If you go for a VSD they can start much more often. You could also get a thing called an OSC which the condensate from the compressor drains into and it separates the oil from the water before draining the water into the normal drains.
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.
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!
I agree with how you've dropped the lines and got water traps at the bottom. At least it comes out of the pipe that way. Also it's faster to just wire up three phases to the motor randomly and then test for direction and if going the wrong way, you swap any two. So you have a 50% chance of getting it right first time. That's why he started it up and it went the wrong way. If you sit around trying to nut it out and then wire it up how you think it should be, it is GUARANTEED to go the wrong way first time.
I bet if you build a nice tight carpet lined 3/4" plywood enclosure around it, and maybe plumb the intake somewhere, it'd be hard to tell if it were running. Mass and freedom of gaps are main keys to acoustic insulation... don't forget to design in provisions for cooling air and maintenance should you do it.
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
Well we currently have 3 screw compressors, at $25-30k each. Our old Atlas (bought used at $13k I believe) is down, and I'll be the guy rebuilding it. Enjoyed the video even if it wasn't really relevant to me.
I am curious, there was actually a discussion about this on one of the machinist forums with how far you have come. From your days in your city apartment to now owning a full blown machine shop. We can't help but notice how you are dropping large sums of money on tools, and we can't help but think you are over extending yourself on budget. Perhaps it is none of our business, but you are inspiring, it makes most of us happy to see you doing well, but also leaves the question, how are you doing well? I don't see many products for sale on your page. Is there more to the story? For those of us who would like to do the same as you, any insight would be greatly appreciated.
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 !
We have a kieser screw compressor using the oil and and air mix works wonders for our machines we haven't had to fill our pneumatic machines oil wells for 12months
You said in the beginning of the video that you where hoping for a "computer" on the compressor... so you can control the start/stop of the compressor. There should be a timer in the electrical cabinet of the compressor so you can run the compressor in "constant run mode". Most are set to run anywhere from 5-7 minutes before turning off after reaching you set pressure. Also constant run mode saves a lot of energy and money from starting. We recommend it if your compressor is starting more than 5-7 times an hour. Also check out Teseo pipe systems. It will get rid of your bulky manifolds for your drop ends.
That particular Atlas Copco only run's start stop, it has only a check valve on the inlet not a controllable inlet valve
Aaaa ok I wondered that.
no refrigerated drier, you can't get good dry air without it, you may think it is dry close to compressor system but you will find moisture condensing closer to the end of a line. long term the screw will deliver air longer than a reciprocating compressor only if they are maintain if not keep your recip. and patch it up
screw type is the way to go for sure,our service trucks have them now and we beat them up daily,PTO driven operating @ 175 psi driving 1 inch impact all day,but,our big one was 11 grand,worth it just not to hear a piston type all day
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:)
Awww, look at Judd. He's such a beautiful boy!
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
Good luck with the new compressor you'll need it!
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.
worked on scroll compressors for 14 years in refrigeration.
the trick why don't like stop starting is compression in the scrolls and that couse high startup torque. and that damage the motor and bearings and scroll bearings . there is more going on in there but I'll keep it short .
+NYC CNC no its the gas or compressed air and oil sitting in between the two scrolls. and takes a few seconds to bleed out and drop to equal pressure on both sides of the scrolls.
I hope this helps a bit more
allways use the best oil you can with the Wright viscosity and never skip on maintenance and you be fine .
I favor scroll compressors over any other compressor.
thanks for awesome videos man . and thanks for sharing all the information. hope I helped you out a bit
Personal experience in a combination dental office/large dental lab/insurance office building, 5 hp 2 stage compressor in a 3x12 foot room immediately adjacent to insurance offices and hallway.
1. Intake piped from outside building resulted in noise of compressor being limited to valves and gentle hum of motor which was 5hp, 3 phase. This was a Quincy unit, meant for supplying air to HVAC controls so low oil loss. Flexible SS hoses connected the unit which was mounted on rubber isolation mounts.
2. Air cooled air prior to refrigerated dryer, then stored in a tank. If wet air is stored in a tank it was my experience the tank corroded and the automatic valve plugged- very annoying.
3. If I recall, Quincy compressor approx $2K and about 21cfm/minute free air
4. If dependability is an issue, make provision for two compressors at time of installation - when that is an issue, add a second compressor. This has the effect to maximize return on capital. In business there is a capital/labor ratio. The more capital, the less the labor - as an owner you are labor.
5. If heavy surge air supply is a requirement, purchase a used surge tank. Large(depends on your definitions) seem to go for about $400 coming out of industrial settings, see HoffonLineauctions which is a good source of these things.
6. This air supply was further filtered in coalescing filters sufficient to be acceptable to run a dental drill(this was verified by supplier prior to installation) a well a a Comco blaster in the dental laboratory with no issues over a period of 30 years. The lab was the big user with blast cabinets that used the 20 cuft/minute air.
Properly maintained, the Quincy never missed a beat and is still running to this day in the same setting without issues.
I work in a printing shop and we got a couple of 50 hp rotary screw compressor. they are on all the time. we would not use them without a dryer. if you run it without a dryer you would get water and oil in your air lines which will ruin all your selenoid driven valves. the oil will rot your seals.
the sweeping bends are nice because psi is lost if volume cannot move smooth I had to learn all this because of my device.
Great info! Why not build a utility room with some good heavy block and concrete to house the compressors?
you may be interested in what are called dirt legs or drip legs when you have a drop you use a tee to pull ff the gas and extend the drop to let water oil what have you drop in to the pipe below the tee these are used in heating gas pipe
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.
Screw compressors are the way to go. I'm about to upgrade my shop to a 100cfm variable speed IR so I can install some new machines. The compressor in this vid is great for running a constant air load but not so great for intermittent load. Variable speed units provide better efficiency over an on/off unit when used below full capacity. In my case a variable speed compressor is going to save me a ton on the electric bill. The downside is initial cost, and the added complexity of a VFD which makes it more difficult and expensive to repair should the VFD fail. Saw it happen when I was doing plant maintenance... cost 7k and 2wk lead time on a new VFD for a 25hp unit.
Exterior intake pipe.
Quincy had intake filters for exterior use with replaceable elements. This addresses keeping critters, etc. out of the compressor. From the compressor point of view, it is important to keep dust and grit out of it, think of an air cleaner on an automobile. We used PVC pipe for the intake line, probably 1 or 1.5" to reduce friction loss.
Surge tanks seem to be generally about 300-400 gallons to be worth while, heavy industrial settings have much larger tanks. If one were purchased used out of an industrial setting that was surplus to continuing operations and was stamped, there would be some assurance the tank would not be a safety issue.
My concern was always the tank rusting and then bursting - it seems we stored air at 175lbs/in squared. That is a great deal of energy in one place if the tank fails.
Our last screw compressor was an atlas copco GA5 35 cfm after a 65 cfm Ingersol Rand that was running 2 large air powered printing machine. Fantastic machine, however we were not well aware of the stop/start cycles setting. When we downsized, the GA5 was essentially producing shop air only to a large receiver tank. We had barely used it over a period of 5 years. Short story long, the air end was damaged by water in the oil and rusted bearings on the screws, and followed with damage to the screws. 4.5k to rebuild ouch! So after the damage was done, we were told the computer was programmable to keep it running and allow it to get up to temperature, evaporating the moisture out of the oil and thus not getting fucked. Expensive lesson to learn, we ended up selling it for scrap value. I now have a vane compressor which doesn't have any of the fancy refrigeration but pumps a stack load of air at much cheaper price and quieter. As you say, screw compressors are awesome for continuous supply
yes, we were made aware of this and programmed the run-time as you were talking about, remaining on idle for longer periods. this was not originally set up when commissioned, so the compressor worked for a number of years starting as required then stopping once pressure was reached, the oil was never really hot, so the moisture remained in oil, causing corrosion. We ended up going to a small 17cfm piston compressor for shop air, and only turning on the screw for spray painting and sandblasting after spending $1500 to have just the bearings replaced in the air end. (not spending $4500 on a new pair of screws), the machine was sat idle unused, then when i next went to use it for sandblasting it would not generate pressure. very sad end to an awesome machine, we got $500 for it as is when we moved shops
to clarify, the GA5 did have a run computer, we were not aware of a possible issue, and the computer was not commissioned to keep it running, and even with a computer we still suffered a major air end failure. The computer AND appropriate programming would have helped
...retrofitting a controller to these machines can be an expensive way to go about solving run cycle issues. The simplest thing to do is have a multi function timer installed between the pressure switch and the start/stop circuits (contactor) and you can simply dial the time dial to whatever setting you wish and once the pressure switch unloads the compressor, instead of shutting down the machine instantly...it will run unloaded (idle) for the set time before shutting down...and if the pressure switch cycles before the time is up it resets and loads.
...but saying all that, I understand some of those small Copcos don't have an inlet valve that can be cycled...in which case you're stuck start/stop...those type aren't very popular around here...come to think of it we don't have any in our client fleet...lol.
I did not read all the comments. Maybe it was already said maybe not.
One of the reasons they like to continually run them is some of the starters in big plants cost 20 grand. that have say a 200 hp to 500hp air compressor. It is bad on the starter to start the machine repeatadly.
The oil in the screw is noy to lube but to seal.
There is no contact between the 2 screws or the housing.
That's why you have 2 helical gears right next to the screw, to sync them and avoid the contact and the wear.
The oil in a screw compressor is for three things, a seal as you mentioned also a lube and the coolant.
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.
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
There are lots of designs out there that could eliminate the noise. One design is like having two electric linear actuators that work together and compress the air into the chamber. Just like that.
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
Like someone said below, your biggest problem is that you have gone from the large blue tank to the smaller integral gray tank. Air compressor systems need 3 things: CAPACITY, CAPACITY, CAPACITY. Either plumb in that old blue tank in for extra capacity or buy a new one that is even larger. As it is now multiple machines coming on around your shop at the same time is going to instantly drain your small capacity. I've seen many problems solved in saw mills and other manufacturing plants solved by simply increasing the capacity.
If the noise was your biggest concern building a sound proof room/box around the reciprocating air compressor is an option.
I really wish there was more information on these things. Ingersoll-Rand, Chicago Pneumatic, Quincy, and countless other companies make these but there is virtually zero information or comparisons online.
This may sound like a dumb idea, but have you ever considered using something like a 'baby monitor' for your machines? A microphone at the work station tied into a bluetooth earpiece could provide a level of peace when you must walk away.
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.
I was thinking if you had a second, smaller piston type compressor back, in the opposite corner of your shop you could set the pressure switch to kick on at a higher threshold than the big one is set at and when the system cycles from off to on, the smaller compressor comes on first. If the demand is not too high, this might be all you need, thus preventing your screw compressor from having to come on at all. If demand is a bit higher, say two guys running grinders or using a spray gun or more, the small compressor wouldn't keep up with demand so the pressure drops to the next lower level kicking on the screw-pressor. Of course it kind of kills your desire for a quiet environment but it would keep your total capacity very high yet prevent undue cycling of the big guy. Oh.. also set the OFF switch on the small compressor at a lower pressure than the screw-pressor and that will keep it going longer, or as long as high air demand calls for even after the small compressor is off.
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!
Cool vid mate I look after 4 centac compressors, 5 atlas ZR comps 2 atlas ZT900, 20 kaeser ASD 50, and there is more Low pressure ones lol where I work the one you got will do you workshop great the dryer side are not so good but if in low humidity there fine where I am we have high humidity we got some huge dryers.
+NYC CNC yeah it would be cost we run all our ring main comps straight into dryers on 12" manifolds running out to an 8" ring main about 2km in length. Can see they would run yours with the tank so it can catch any oil that could get through the separator. When I'm in work next will get you a number of the auto drains we use for you to compare.
I used alot of machine from atlas corp and our enviroment is very harsh and their machine are very reliable and work 24-7 for 365 days. They are one of the best company on the market. I live in Malta so the climate does not forgive....
John
Why are frequent starts and stops bad? Starting current is 4 to 9 times running current. On compressors this may be for 10 to 40 second especialy so on recips ie piston. On larger motors they wil specify number of starts per hour. Both the windings and the rotor get heated durning start. Both recips and rotary or any other compressor for that matter benefit from unloaders. Yes the compressor is stil rotating but the discharge pressure is zero.
I just read BCB Bloc below he talks abot heating the compressor piston or scews in a rotary -- good comment. Hot cold at frequent intervals is hard on equipment.
Air lines look OK to me I like the take air out the top of the pipe. Water does condense in the headers so they should slope. A tank at the end of a hader makes a handy place to dump the water and also helps to lower friction loss in the piping.
Down legs to connectors or machines should have the tee as you showed with a dran valve at bottom.
Water in compressed air is hard on air motors and actuators. After coolers go a long ways to remove water from air. If ypu put one close to compressor discharge you can use warmed water to heat other rooms. Cold water from aftercoolers ie from the air can be used as source of chill water. You spent money to heat that water in compressing it then more to cool it so why send the results down the drain?
Auto drains ?? Dont think much of em - fine when they work BUT put in a manual valve to check em - everytime I did this they worked flawlessly - I dont understand that - must be Murphy Law.
Dan Bentler