Profile: DSTI - Rotary Unions specializes in the design and manufacture of rotary unions & swivel joint products. Our rotary union products are used to transfer hydraulic oil, chemicals, water, air, and a variety of other liquids & gases from stationary inlets to rotating outlets. We offer a comprehensive line of standard rotary union products & options in addition to providing complete specialized rotary union engineering services including design, simulation, manufacturing, assembly, and testing.