How Do Rotary Unions Work? 

Thanks Carlos!

You are correct! Rotary unions are also bidirectional meaning the media can travel into the shaft and out the housing or vice versa. For it to all work correctly the proper sealing technology must be used. Media type, temp, pressure, duty cycle, etc. all play a big role.

@@DstiRotaryUnions Thanks for confirming it. I was curious how it works since I use a machine with this kind of thing at my job (it has four entrances and exits instead of two, but the intakes are all at different heights)

@@urbanberndtsson You're welcome. If you check out our website we have standard rotary unions with 1 - 24 passages. www.dsti.com/rotary-unions/standard/

Rotary unions themselves do not have any sort of drive mechanism. Excavators have swing drive bearings and hydraulic motors that rotate the cab. This allows the mounted rotary union to rotate as the cab rotates. Hope this helps and thanks for checking out our video.

I see. I didn't get the notification but thanks for following up!

@@DstiRotaryUnions Thank you!!! Is there a video of how the swing drive bearings and hydraulic motors actually create the rotation?

@@gregwoolsey2215 They don't need to in that application, as they don't rotate (relative to the cabin) but would usually act upon an outer ring around the bearing via a gear drive. This could however be directly controlled (hydraulically) in the body from the cab with a rotary union.

@@hierotochan Like a starter on the fly wheel?

In most cases yes, each drive motor requires two hoses; one for the supply and one for the return. However, it can vary by manufacturer and equipment size. Thanks for checking out our video!

Do you have a video for disassembly for duff Norton mcseries rotary union?