Small Industrial Compressors - a small sentance but a big topic.
From the start we will assume that you have 3 phase electric.
The basis of Industrial Compressors is the Piston Type. In my 1st guide I go into the various qualities and what to expect, but basically Piston compressors are the cheapest way of compressing air for use in industry. They are also the cheapest type of compressor available.
The quality of air produced is normally quite poor, being both hot and wet. Most applications do not want either hot or wet air and so you can have a problem before you start. You can use various filters and even a refigerant dryer to make the air quality better.
The next step up is to either screw or vane compressor, there is little to choose between the two and the air quality is usually a lot better, particularly if a refigerant dryer is used. This is the quality of air normally required for CNC machinery or for car bodyshops.
The quality of these machines is very different to cheap piston compressors and of course they cost a lot more. A basic machine would start around £3000 for a 10hp and then you will need a tank and maybe a dryer. Of course these machines are available used, but you have to be careful. most people who buy a new one will work it hard - probably very hard - for 10 years or so and then it enters the used market. Its at this point that you have to be careful that you dont buy someone elses problems as this can be very expensive.
Of course it is possible to get a good used one, prefferably with a service history, we always have a few good examples available and so you can always give us a call.
A final point to remeber, the imported piston compressor of today is very different from the British piston compressor of 30 years ago. The new modern imported unit is a real lightweight compared to the real thing and will not grow old. Of course it all depends what you are going to use it for - we have customers who have 15 year old imported compressors and they are still ok - but their useage is fairly light and ocassional. If you have a true industrial application for say 10 hours a day 5.5 days a week, this is very different and I doubt if a cheap piston compressor will last you 15weeks, definatley not 15 years.
The final point to remember is that piston compressors have a MAXIMUM 40 -50% duty cycle, this means they dont want to work hard - you need a true industrial machine for that.
In conclusion even fairly expensive piston compressors are the poor relative to screw and vane machines - but they have their place in the market and we sell many every year.