Tools, Sharpening and Power Machinery - rotary air compressors for homeowners
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diy99999
06-17-09, 11:01 AM
is anyone making a rotary screw type air compressor with at least 20 gallon tank for home use under 1000$ ?
furd
06-19-09, 05:32 PM
As a person with extensive experience concerning industrial sized rotary screw compressors I would advise you to stay far away from anything under $1,000 or marketed to homeowners.
I once worked where there was an emergency back-up control air compressor which was considered a "tiny" rotary screw. It had a 20 or 25 horsepower motor on an 80 gallon tank. That machine was a POS even though it was of a brand highly regarded in larger sizes.
I once worked where there was an emergency back-up control air compressor which was considered a "tiny" rotary screw. It had a 20 or 25 horsepower motor on an 80 gallon tank. That machine was a POS even though it was of a brand highly regarded in larger sizes.
nap
06-19-09, 09:55 PM
I do not believe I have ever seen a screw under $1000.
diy99999
06-20-09, 11:03 AM
furd since you are an expert... what about the design doesnt work with smaller sizes..??? and what do you think of the Ingersoll garage mate
piston..???? read several good reviews and 1 bad. that seems to be best
bet for homeowners who want power so far... they run about 450$..
btw I saw some pics of the screw assembly on the Quincy site.
I would have guessed that they would just use a bunch of circular vanes
in series like a jet engine except without the back set. How exactly do they work??
piston..???? read several good reviews and 1 bad. that seems to be best
bet for homeowners who want power so far... they run about 450$..
btw I saw some pics of the screw assembly on the Quincy site.
I would have guessed that they would just use a bunch of circular vanes
in series like a jet engine except without the back set. How exactly do they work??
nap
06-20-09, 11:22 AM
they use a roots type compressor:
http://static.howstuffworks.com/gif/super-charger-11.jpg
http://static.howstuffworks.com/gif/super-charger-11.jpg
Gunguy45
06-20-09, 11:35 AM
Nap Are you sure...I didn't think a roots type could get pressure that high...
Per wiki (I know, I know...lol)...Scroll compressor - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Scroll_pump)
Oops..nevermind...realized I searched scroll..not screw..Rotary screw compressor - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Rotary_screw_compressor)
Per wiki (I know, I know...lol)...Scroll compressor - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Scroll_pump)
Oops..nevermind...realized I searched scroll..not screw..Rotary screw compressor - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Rotary_screw_compressor)
furd
06-22-09, 01:02 PM
Nap covered the operation of the rotary screw compressor. With this type of compressor the circulating oil has three jobs, cooling sealing and lubrication. Compressing air creates a whole lot of heat and that heat needs to be rejected. Rotary screw compressors are either water cooled or air cooled and the oil MUST go through a cooler to reject the heat. One tiny (you think) leak will cause you to leak all the oil in a matter of seconds and then the compressor will self destruct. You need some pretty fine filtration on the oil or you will destroy the close tolerances between the rotors and the scroll or the rotors themselves.
The compressors I had charge of contained anywhere from 70 to 110 gallons of oil and from room temperature it took maybe two or three minutes to get that entire volume of oil up to about 180 degrees or higher and that was with water cooled machines. The smallest machines were about 200 horsepower and the largest was 800 horsepower. That large machine circulated the oil at 200 gallons per minute.
Rotary screw machines have what is called an "air-oil separator" on the air outlet between the oil reservoir and the air outlet. These must be periodically changed as the eventually lose their effectiveness becoming supersaturated with oil. These machines ALL have sufficient oil carryover to make them pretty much useless for spray painting unless you add some really fine filtration after the compressor.
The best (in my opinion) air compressor for a home shop is a belt driven twin piston reciprocating machine with splash lubrication. The oil requirements are pretty simple, mostly just needs to be slippery. They run forever as long as they have oil and they have a moderate cost.
The compressors I had charge of contained anywhere from 70 to 110 gallons of oil and from room temperature it took maybe two or three minutes to get that entire volume of oil up to about 180 degrees or higher and that was with water cooled machines. The smallest machines were about 200 horsepower and the largest was 800 horsepower. That large machine circulated the oil at 200 gallons per minute.
Rotary screw machines have what is called an "air-oil separator" on the air outlet between the oil reservoir and the air outlet. These must be periodically changed as the eventually lose their effectiveness becoming supersaturated with oil. These machines ALL have sufficient oil carryover to make them pretty much useless for spray painting unless you add some really fine filtration after the compressor.
The best (in my opinion) air compressor for a home shop is a belt driven twin piston reciprocating machine with splash lubrication. The oil requirements are pretty simple, mostly just needs to be slippery. They run forever as long as they have oil and they have a moderate cost.