Starting a small body shop (2 or 3 workers) Has anybody have any experience with a( Atlas Copco) Atlas model # GX5FF screw compressor or a Kaeser SX7.5 screw compressor.Both with air dryers. Pros or Cons. Thanks in advance, Steve
We have a Kaeser SX15 here in addition to two piston compressors. The Kaeser is fantastic, we installed it inside the building and it is really quiet running. The air drier works very well and so does their filter system. We didnt even bolt it to the floor, we just sat it on isolator pads (from McMaster). From the compressor to the wall, we used metal flex isolation hose. Would buy one again. Given that, I am also looking to buy a screw compressor for the garage at home....so it has to be single phase. The Kaser and Atlas compressors in that size both are pretty nice. It seems like I can get a better deal on an Atlas (5hp single phase with drier) than a Kaeser. I think that you would be happy with either brand.
I had a Kaeser at my business for years and loved it. They are quiet and very efficient. The compressed air is nice and clean. We had a second air dryer in series with the Kaeser air dryer since we needed really dry air but I am not sure that we really needed the second dryer since the Kaeser dryer seemed to be doing a really good job. Remember to keep up with the servicing (important on this type of compressor) and you will be a happy camper with a Kaeser.
I worked for Atlas Copco for 7 years and can honestly say, you'll have a tough time finding a better product.
When I was compressor shopping I was told that the risk of getting oil in the air is much higher with a screw type. Because the air would be used for painting and cleaning parts for other processes I decided not to risk problems. In addition to the potential oil issue, from what I have read and been told, screw compressors are more efficient than piston compressors, are more durable, and typically don't produce more than about 125 PSI. They are quite a bit more expensive, and make more sense where very high volumes of air are needed.
You will get oil particulates down stream no matter what. I install these units daily, if your main use is tooling air you should have no issues. But if you are going to paint you really need to step up your filtration at the booth and even then you can and most likely will have an issue at some point. Service, its not cheap and if you skimp at all you can rest assure you will have a failure. One scenario could be a separator failure if it blows the majority of oil in the unit will go down stream into your system because your filters and dryer wont be able to cover that amount of oilflow. once the oil in that amount is out there you will need to be even more vigilant about point of use filtration at your booth. The other failure is flash fire from prolonged service. the inside of unit can catch fire. While these are extreme you do need to consider them when making the decision. As well as run time, you should be able to run the unit 60-80% for the most of the shift you work them at, if you cant do that you may get carry over of oil as well due to running in an unloaded state and not scavenging oil from the seperator housing properly saturating your seperator element. Also running for long enough time to really burn off the condensate these units produce as well, they need to maintain enough temp for long enough to do so. Some of these smaller 5hp units do not modulate and run in a start stop manner like a piston wich temps may never rise enough to help and codensate can stay within the sump and cause wear on your filtration. Check with your local compressor houses to see what service parts will cost you for the year. You may be surprised. Personally unless you are extremely high voulume body shop I would run with a piston unit and dryer filter set up. Your service costs will be less.
Do all compressors have an oil problem to a certain extent? This compressor will probably be 7.5 HP Steve
I agree with meddler. You need to know all screw compressors mix the air with the oil then are separated later. A piston compressor just makes air. I would be nervous using a screw compressor for nice paint work. We use a couple kaesers in our factory and they are a great machine for a factory.
My info about the oil issue came from the best compressor shop in the area, from one of the owners who has been in the business his entire life. What he said about screw compressors was the same as what others here have said. One thing to think about; the cost for a good screw compressor could buy several replacement recips,(assuming the couldn't be repaired).
Problem is kind of a loose term when it comes to these types of compressors. From the manufactures specs,each type is alotted a certain amount of parts per million of oil carry over its like 3 parts per million or something like that I cant remember for sure. Its in the design of the unit. Like stated "flooded screws" send compressed oil and air into a sump and are separated with filtration allowing the "air" to go through the discharge almost oil free. For most manufacturing plants and shops using the air for tooling and machinery this is fine and can be filtered out even more. Honestly there are even breathing air systems with flooded screws but the filtration is beyond expensive. problems occur from lack of maintenance and improper system design.
what kind of power do you have avail? Also how many guys do you anticipate working at one time, one guy on a DA and one guy painting can use up what a 7.5 Hp unit can put out and honestly probably wont keep up. Most of the smaller shops I service use 15hp and some get by on 10 hp units. lets go back to power, whats avail in your building?
Meddler1, we are out of town and have single phase power. The electrician is going to check volts (208 220 etc) We are getting a phase converter for the paint booth( future cure downdraft) the building is up , The is floor in ( hot water heat) walls and ceiling done Morton building. The building is 54X99 ( body shop 54X60 my shop 54X39) with a 32X36 house attached. This is the last time I'm building( read that as being 61) and i want to do it right the first time. Steve
Here is the 7.5HP compressor that I bought. It more $$$ than I wanted to spend but its made in the USA. It is a single phase 7.5 that built with specs of a 10hp.
Efficiency between one compressor and the next can vary quite a bit. A 7 1/2 HP unit from one manufacturer may supply what another make would take 10 HP to produce.
Just purchased an air compressor that is similar to yours oldwood. I did quite a bit of research before I bought the EMAX. Built in the USA. It looks like you have the same pump. 7.5hp, 26.5 cfm, low rpm 600, quiet, less vibration, 80 gal horzontal tank and runs 35% cooler than normal pumps for low condensation. Five year warranty on the pump. It was the best choice for my home shop.
Another consideration; The use of a "phase converter" a 5HP motor requires a 7HP converter. There is a loss somewhere in the use of a converter., and you could only run one piece of equipment at a time or have multiple converters for each piede of equipment. Pat
He said he doesn't have three phase power available. Single phase 7 1/2 HP motors are available, and one of those wouldn't need a phase converter. At 220 volts the motor would draw about 30 amps running and less than 40 amps starting. Not insignificant, but not unreasonable either.
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