7.5hp rotary screw pricing.

[jsheridan]

I hear the elite brand is the Kaesers? What do those run?

We have a BOGE 25 horser out here.. I don't want to know how much that cost 

[Ryan]

I have a 7.5 kaeser, separate chiller. When I looked I believe the all-in-one unit was in the neighborhood of 8k. Buying separately I saved around 1k-$1500 dollars. More space but cheaper price

[Prosperi-Tees]

So nobody ever looked into rotary vane compressors? Been researching and it seems the better way to go and priced about the same.

[Gilligan]

So nobody ever looked into rotary vane compressors? Been researching and it seems the better way to go and priced about the same.

When Jason brought it up a year or so ago I looked into them and I liked what I saw... But I know nothing more than what you do probably.

[Binkspot]

Lots of cfm, lower pressures, generate a lot of heat. Used in many cases for "fluffing" dry bulk material to pump it where you need a lot of volume and less pressure. Vans and barrel are prone to wear, usually higher hp to achieve higher pressure. Also prone to a loud hum or whine noise not unlike most employes.

If the vanes wear to a certain point they can fall out of their slot which usually ends up being a catastrophic failure.

Not saying don't get one but be sure you know what your getting. 

[Prosperi-Tees]

So would the rotary vane require a high temp air dryer as opposed to a regular refrigerated dryer? I think I may need a high temp anyway. I noticed on some that the recommended ambient temp for a refrigerated air dryer is 110 degrees. I know it's hotter than that in my shop during the summer.

[Binkspot]

The air is not as hot as a piston type but the pump it self gets hot just from the friction of the vanes and air.

[Prosperi-Tees]

hmmm they (rotary vane mfgs) tout them as having less friction and less wear than the rotary screw and will outlast a screw 2-3 times over due to that.

[Binkspot]

Less friction then a screw yes but wear I find hard to believe. But you would also have to compare apples to apples to make that statement. We had vane type that would be overhauled by the factory every 10-15k hrs as per their service schedule. Screw compressors sitting next the them with 30-35k hrs and other then routine service were never touched.   

[Prosperi-Tees]

Thanks Brian, got alot to consider. Hard to make a decision when it cost between 6-8K. I have a tough time spending 100 bucks!

[Prosperi-Tees]

Now another wrench... Variable speed or fixed speed rotary screw?

[ericheartsu]

We have a variable speed screw compressor that we bought new from Atlas Copco. I think all together it was $10k. We already had a seperate chiller that was compatible.

Nothing to complain about. Runs great, easy to use, and service for A.C. is awesome.

[Prosperi-Tees]

I just thought of something. Could I buy a base mounted rotary screw and plumb it into my existing air compressors tank?

[jvanick]

I just thought of something. Could I buy a base mounted rotary screw and plumb it into my existing air compressors tank?

Absolutely you can do this.... just get the right size hoses/fittings, and away you go.

You do want to make sure that your existing tank is in good shape and ASME stamped to handle the pressure.

[Prosperi-Tees]

One last question and I am done with my research I hope. I noticed most compressors you have to specify your psi when ordering, like 125 and 150 psi are most common. What is recommended as it pertains to us since most press specs are xx cfm @ 100 psi. Would a 125 psi compressor run more often than a 150 psi?
I think what im trying to ask what difference would a 125 psi over a 150 psi be since the air is regulated at the press to be about 100 psi?