DSTI recently designed the custom stainless steel rotary union pictured below. Its is used to transfer supply/return cooling water to equipment that rotates up to 500 rpm. It is a 2-passage design, with 2.0" NPT inlets. It is pictured with their standard LT Series 2-passage unions for scale.

DSTI is the industry leader in custom rotary union design & manufacturing. They have a staff of (5) Engineers dedicated strictly to custom rotary union design & development. They are specialists in rotary seal design, and know from experience what works best for each specific application. You can be confident that when working with DSTI on your rotary union application you are working with experts in the industry.