Swivel Selection Guide
Selecting The Most Correct Type and Kind of Swivel Joint
Browse Hydraulics Inc.’s comprehensive library of swivel selection guides and engineering application criteria below to determine the ideal live swivel joint configuration for your fluid power machinery. Selecting the correct hydraulic swivel requires analyzing several critical operational parameters, including maximum system operating pressure, dynamic flow rate requirements, ambient temperature ranges, media compatibility, port thread configurations, and expected equipment articulation duty cycles across heavy machinery, energy, forestry, marine, and industrial environments.
Choosing between inline live swivels and 90-degree elbow swivel configurations depends heavily on space constraints, hose routing geometry, and fluid flow direction. Inline swivels are ideal for linear hose rotation where twisting stress must be absorbed along the longitudinal axis, while 90-degree swivels eliminate tight hose bends, reduce mechanical fatigue, and save installation space in compact machine envelopes. Properly sizing the swivel port diameter prevents excessive fluid velocity, internal turbulence, heat generation, and unwanted system pressure drops across continuous duty cycles.
Seal elastomer selection is another vital factor in the swivel selection process. Standard Nitrile (Buna-N) seals suit standard petroleum-based hydraulic oils, whereas specialized Fluorocarbon (Viton®) or Ethylene Propylene (EPDM) seals are necessary for high-temperature applications, synthetic fluids, or aggressive chemical media. Furthermore, specifying the correct case material and surface plating protects the swivel body against harsh atmospheric corrosion, salt spray exposure, and abrasive airborne particulate matter common to outdoor work sites.
Additionally, evaluating rotational torque requirements under full system operating pressure ensures smooth articulation without placing unnecessary strain on connected hydraulic lines or drive motors. Incorporating hardened ball-race bearing designs further stabilizes internal components against minor side-loading shifts during intense equipment operation. By utilizing Hydraulics Inc.’s technical selection resources and sizing charts, equipment designers ensure optimal rotational performance, extended hose service life, zero leakage, and long-term reliability in demanding field applications.
How to Distinguish Types of Swivel Joints
The two types of swivel joints discussed here are distinguished by their load bearing mechanisms. Both types require at least two components, commonly referred to as the stem and the barrel.
The first type swivel (Swivel A), is comprised of a barrel fluid port positioned to rotate on a plane 90º to the stem axis. This swivel includes two load bearing mechanisms classed as journal bearings. The swivel’s barrel bore includes two load bearing lands separated by a fluid passage. The stem’s outer diameter includes bearing lands, complementing the barrel and with space to allow the stem fluid passage to communicate fluid to the barrel port. The two stem bearing lands further include equal size seals for containing the fluid. By nature of equal seal size, (pressure balanced) the effect of fluid pressure on the stem and barrel creates no load on the bearings. Thus bearing life is solely dependent upon external loading. To achieve maximum bearing life, all angular deflection induced through the piping system should be kept to a minimum.
The second type swivel (Swivel B), is distinguished by opposed barrel and stem fluid ports on a common axis. This in-line port relation depends on a single load bearing mechanism, classed as a combination radial-thrust bearing. The swivel’s barrel bore provides an axial ball bearing raceway that is distanced from the barrel’s seal gland area. The swivel’s stem provided an axial ball raceway and a seal groove to coincide with the barrel bore. In assembly, the balls retain the barrel to the stem while permitting axial rotation between the two components. These features require the bearing to withstand both thrust and stress from angular deflection of piping. With no deflection, bearing life is a function of thrust from fluid pressure.