Industrial swivel unions – general information
Industrial swivel joints – rotary joints, designed for fixed installations or flexible hose assembly connections, wherever continuous rotary motion or oscillations between certain parts of the installation occur. The constant rotary motion occurs in many industrial machines and equipment, where one part of the machine (drum, rotor, cylinder) rotates but the base of the machine is fixed. Such solutions are typical to e.g. the paper-making industry, printing, textile industry, rubber and plastics industry, chemical and petrochemical industry.
The swivel joints are used to provide a self-adjusting connection in the system where hoses, hose assemblies or couplings are twisted due to displacement. The application of the swivel joints eliminates the damaging stress of the elements.
Swivel joints are made of either carbon steel, aluminium, brass or stainless steel. The rotary motion is achieved through bearing (usually ball bearings), with the appropriate sealing surface. Some swivel joints (with two bearing tracks) can carry a bending moment load. The swivel couplings usually have threaded connections or flange connections. A multi-passage rotary joint allows several independent feed or return lines conveying different media simultaneously through the swivel joint.
The rotary joints are used in industrial installations to transfer water, air, steam, heat transfer oil (thermal oil), hydraulic oil and many other.
For more swivel joints, see also HYDRAULICS and HIGH PRESSURE section.