The single-pass type means that the medium flows through the rotary joint only in one direction, generally flowing in from the rotary joint at one end of the equipment and out from the rotary joint at the other end of the equipment;Or the medium is sprayed at the place where the equipment needs to be cooled, such as machine tool spindle rotary joint.(there is only one path with a rotary joint capable of introducing or exporting media);(As shown in the figure below).
Double-pass type: the medium flows in and out of the same rotary joint, and the double-pass rotary joint is matched with the siphon (inner tube) (the rotary joint has two channels and has the function of introducing the medium and output at the same time).(Figure below).
In general, steam rotary joints, water rotary joints, thermal oil rotary joints have a single channel and a double channel.
Multi-channel (multi-steering) rotary joint: a rotary joint having three or more channels and capable of simultaneously introducing or exporting one or more media.This type of rotary joint is usually customized according to the needs of the equipment, and hydraulic rotary joint is in the majority.