O/T Air compressors, rotary screw or hydrovane ?

[Gutty]

So i figure alot of you guys do machining aswell as drawing/programing.

Well i'm after a new compressor and thought you guys might be able to give me your opinions.

I'm after something with about 30hp and pumping over 110cf/minute.

 

If you were in my shoes would you be looking at Rotary screw type compressors or Hydrovane types ?

 

All opinions are appreciated

Thanks

Matt

 

[ 10-28-2003, 06:12 PM: Message edited by: Gutty ]

[crazy^millman]

Well depends on your CFM needs more than anything. If you need the pressure or the constant CFM. I like the rotary cause it doesnt require a tank and can pretty much support a whole shop with all your needs. I dont know much about the other but the last place and this place have abd I have never have a problem with pressure and both places have over 50 people all using air in one way or another.

 

Crayz Millman

[Chris Rizzo]

I see your in Australia, huh? Here in the states, there seems to be a plethora of good used compressors at auctions. Just saw a 30hp Atlas Copco with like 500 hours go for 3000$. We sunk our $ into a good dryer, and decided to run our old vane compressor into the ground.

[Tony]

Screw all the way It Gives you air Instantly

as fast as you can snap your fingers.

We have a Ton of Air driven automation here and there cannot be any lag time.

Piston compressors and a "Bank" system used to be the Norm.

[MetalMarvels]

Screw-type or scroll-type! Mine is a scroll-type that is actually inside my shop and I usually can't even hear it running - the air dryer is louder (of course I did put acoustic foam on the surrounding walls...). It has been a consistent performer over the past 2-1/2 years with only a little preventive maintenance required (change the filters and oil once a year). You can actually hold a normal conversation standing next to it while it is running!!! The screw type that we have at Honeywell has been very reliable also and is only a little louder - makes air FAST!

 

[ 10-29-2003, 10:34 AM: Message edited by: MetalMarvels ]

[Guest CNC Apps Guy 1]

I believe Screw type are best for machine shops that use a steady amount of air. Also consider an accumulator to help with CFM requirements.

 

JM2C

[chris m]

Screw all the way; Hydrovanes are junk

 

Don't be cheap when it comes to buying your compressor and you'll get years out of it: Sullair, Quincy, Atlas/Copco, make sure you buy a good one.

 

A good dryer is an absolute must.

 

Many shops (like both of the ones I work at) use a 2 cylinder piston compressor as a backup; this allows for continuous operation during service of your primary and a backup in case it goes down. We have our screw compressor plumbed through the piston compressor's tank so that it acts like an accumulator for the system, as James mentioned. Remote air accumulators are also available for short money if you have a particular momentary demand that's causing problems (typically machining center toolchanges).

 

C

[Roger Peterson]

Water cooled, if possible,(much, much, much quieter) screw type with coalescing filter, air dryer, and the more reserve the better. In larger shops remote tanks can greatly reduce the size of piping needed throughout the plant. Personally I preferred Gardner Denver to Atlas copco but that is only because I had to work on them. You will find used Atlas Copco compressors are cheaper. I'm not sure where your cfm requirements came from but chances are that is not a continuous demand. Reserve tanks can take care of that and you will be able to get a smaller more energy efficient compressor to handle your air needs. Lastly, your local air compressor sales company will come in and do an air audit for a minimal cost or free. If you eliminate 75% of your air leaks and rebuild your less than efficient air cylinders you would be suprised on how much that can affect your air volume needs.

 

One last thing most compressors from the last decade or more are not either just on or off. They will have those options as well as some energy saving auto modes. Fist stage will have the motor freewheeling whithout building air pressure. The amps required to keep a 30hp motor spinning without any load is a few amps compared to 60 or more at 240vac. So the more reserve you have the more time at "idle". They will also shut off if they are in "idle" for more than a certain amt of time, this will probably not come into play.

 

 

HTH

 

[ 10-29-2003, 12:41 PM: Message edited by: Roger Peterson ]

[Tony]

Air Compressor story...

A decade ago three apprentices were sent into

The compressor room to change the filter and oil.

The compressor is off BUT full of air still.

The plug comes out all three guys come flying out of there Covered with Oil from head to toe.

Everyone is o.k. and they go home to take showers.

It's around 11:00 a.m.

One of them Catches his Fiancé Driving a Moving truck out of the driveway with all her Crap!

Along with His T.V. Won from the IMTS show from Erowa.

The End

[Chris Rizzo]

Moral of the story :

It's not so bad getting hosed with compressor oil, it might keep you from getting hosed by your fiance!

[Tony]

Hey, There ya Go!

[Guest CNC Apps Guy 1]

We have 4 Sullair LS-12 and 2 500 Gal. Accumulators, 2" "Main" lines through the shop then where they branch off to the machine ('cept for the hogs, errr I mean Mori's" they go to 3/4" then to the "regualr" air hose. We have 2 100 Gal. accumulators in the shop (next to the Mori's) to maintain stable air for 5 horizontals, 15 verticals, an airhose for every machine, some have 2, and a host of other equipment.

 

HTH

[Gutty]

cmr, yes i'm an Aussie. My Company

 

Looks like the Rotary screw is the way to go then ey ?! We are currently running a screw type but have been told we'll get twice the life out of a Hydrovane type. Is this generally true ??

 

Thanks for all the opinions fellas, much appreciated.

 

Lata

Matt

 

[ 10-29-2003, 05:19 PM: Message edited by: Gutty ]