Rotary Screw Compressor feedback ?

[PDM]

Anyone on here with advice or feedback on your rotary screw compressors ?

In particular I'm looking at a Bend Pak RS7580H-603 7.5 hp unit but have been unable to find any reviews or feedback on this fairly new unit. This is going into my new garage/house build that I will be putting a thread up within a month.


http://www.bendpak.com/Air-Compressors/RS7580H603


(and before I get people asking why..... my MAIN criteria is noise.... or lack of noise. My machine shop where this will be stationed has been constructed below my kitchen and living area, and I do NOT want to hear excessive compressor noise upstairs, AND I am within 6 feet of my neighbors property line, so I wish to keep my wife and neighbors happy with my fabrication and playtime in my new garage and shop.)



I recently put a California Air Hot ********* compressor in my race trailer and REALLY like how quiet a compressor can be .


Any feedback or stories of residential rotary screw compressors ? Brands ? Maintenance ?


TYI

Don

 

[2oolhound]

We had an IR 12 HP screw compressor at work. It was excellent but as it wore out the maintenance and parts were atrocious. Example: a thermostat (similar to one in your car) was $900.00. The main shaft with screw gear was $4000 (for the 5 hp compressor,) I couldn't source ours but estimate it would have been $7000ish.

You should look into parts costs for what ever model you are considering.

 

[jallyn]

I am familiar with 200hp IR compressors, variable speed, used in a foundry. They were fairly low maintenance/reliable.

I like the looks of the one you linked to... though it is 3-phase, which you may have in your machine shop but sounds like it is in your basement?

 

[md21722]

Screw compressors are not really intended for intermittent use. They are not mean to be on/off. They have electronics to ramp up and down depending on air usage. I think your best bet is to get a recip that may have a sound proofing. Champion and Quincy both sell compressors this way and I bet a bunch of others do. Here is a Quincy Xtreme video

The one she compares against is a Champion R15 without any sound proofing. Here is a PDF from Champion that explains their Evolution line of enclosed compressors and has a quick comparison between screw and recip. http://www.championpneumatic.com/assets/0/176/184/468/488/eb7ed17a-5b32-4f93-b080-501d9e676f46.pdf I prefer Champion compressors myself. I would give your local compressor dealer a call and see what they can do for you.

 

[md21722]

I'd also consider that compressors that run slower are typically quieter. Something like a Champion R15 at 5HP runs 734 RPM. The Champion R30 at 7.5HP runs 575 RPM and at 10HP runs at 740 RPM. It will be quieter than a Quincy QT 5 HP or 7.5 HP that spins around 900-1000 RPM. So that itself may be "good" enough... depends on if you're trying to make it as quiet as possible, or just eliminate "excessive" noise.

 

[94EG8]

We have an Atlas Copco at work. It hasn't needed anything crazy maintenance wise. The only thing I can think of outside of normal wear and tear was a solenoid for a drain valve. When it ramps up though it's loud.

Considering what it will cost, plus either an RPC or VFD to run it or a single phase motor (I'm assuming you don't have 3 phase power) and the fact that it may not really be all that much quieter depending on how hard it's working I think I'd just buy a 2 stage reciprocating compressor that turns slow.

 

[Jim Johnstone]

I agree with the others, screw compressors are great in factories where there is always something using the air. A single guy in a shop would be better off with a reciprocating compressor. In addition to some of the ones mentioned already, the kellogg 452 spins 560 rpm with a 7.5hp motor. We used to have one at work (machine shop) and you could have a conversation right beside it. I liked how quiet it was so much, I went and found a 452 pump and am in the middle of rebuilding it for my garage.

 

[PDM]

Awesome responses so far..... and yes.... that was a concern with regards to the rotary screw...was how much it had to be run to be efficient.


While this is going into a home based machine shop, I AM in the process of building an 8 car, 4 hoist garage next to the machine shop......so ....there could be 3-4 friends at once working alongside me at any given day I have bead blasters on an air powered Hunter tire machine, along with air jacks on 4 post hoists and bead blast cabinets..... - so yes... combined with air tools, grinders, there can be a fair amount of air being used on any given day. (but it's not a commercial shop - so there may be days where it's never turned on)

I also checked with another main supplier (Lordco) and they have a refurbished Devair 7.5 hp B75TD rotary screw in stock (was dropped in shipping - and rebuilt with full warranty) with a better warranty than the Bend Pak and larger capacity with free shipping for about $500 Cad less. Plus is it's in stock in Vancouver to look at. I'll also check with the local Devair rep to ask about any companys locally I can view/talk to regarding their rotary screw units.

I will also do more research on slower rpm dual stage compressors.

(I'm re-feeding my power direct from the street, so 3 phase is possible....but good catch Jallyn. The remainder of my welders, lathes, presses and hoists are all single phase, so yeah...maybe easier to stick to single phase. (the Devair can run off single phase)

 

[md21722]

The thing with screw is that its meant for some type of constant demand the entire time its on. So basically you would turn it on when your friends show up and turn it off when they go home. They're meant to run all day long. They cost more in electricity for intermittent demand. You can mitigate a recip cycling all day long with a supersize air tank, or multiple tanks. Go for at least 120 gallons. Serious users go for 200-360 gallons. If you put them in series they do double duty as moisture traps. So get an extra tank or two and put your main comp on a 120. I have 2 5HP Champion R15's that go into a 3rd tank, and then feed air to my tools, no problem with condensate even after the compressors have been running for 45 minutes. My neighbors are close by and they don't complain. Especially since when they need brake pads I do it for a 6 pack.

 

[MacMcMacmac]

I'd be leery of how long BendPak is going to support a Chinese made screw that isn't one of their main line of products.

 

[Burgerkong]

Atlas Copco, Sullair or Chicago Pneumatic would be my picks. Get a lower horse one so you can keep it running continuously and a large (or several large) receivers.