Challenge
A U.S. OEM designing and manufacturing semiconductor machinery required a two-passage rotary union that had to fit into a 3” (76 mm) space on one of its new machines. The rotary union needed to be mounted with a clamshell clamp on the nipple and it needed to be capable of transmitting drive torque to another device that was mounted on the end of the rotor. The material going through the rotary union is deionized (DI) water at 86°F (30°C), 90 psig (6 bar), and rotating 90° within 0.3 seconds every 7-30 seconds.

Solution  
This application was outside the operating parameters of standard, off-the-shelf rotary unions and required a custom union solution. Because the two-pass union was going on a new product, the machine design changes occurred often also impacting the design of the rotary union. The final solution was a custom union to handle the DI water, and included Kadant Johnson’s DuraSeal™ sealing technology.

Results 
Despite the frequent changes in design, Kadant Johnson met the tight delivery requirement and one month later received positive feedback that the custom rotary unions work great and have met expectations.