Try these
New
http://www.perryequipment.com/
http://www.peerlessmfg.com/separation_filtration.html
http://www.natcogroup.com/
www.energyweldfab.com
Used
http://www.intertreat.com/index.htm
These are the ones that I come up with off the top of my head, It you need more help, let me know.
Gary...