Depending on the level you want to take this, there are several quality manufacturers of orbital welding equipment. I would suggest GTAW to be the place to start and the 3 main equipment manufacturers are as follows:
ARC Machines - www.arcmachines.com
Liburdi Dimetrics - www.liburdi.com
Magnetech - www.magnatech-europe.com (they do have a USA operation)
I have attached links to these for your info. You might describe your program, location, etc. so readers have a better idea what you are doing. If you are a College/Trade School, some of these suppliers may cut you a good deal on equipment. It is not cheap, with a complete pipe weld setup running upward of $100K, depending on accessories, tracks for various pipe diameters, etc.