Union is an aid to mate two pipes or simply helps in mating two pipes for a continuous flow of fluids/gases.
They have key features of being made from Heat treated materials to withstand High pressures such as 20000psi, They are also supported with Anti Extrusion rings to reduce t friction , this also prevents with fluid leaks.
Swivel Unions are nothing but couplers, again to be further simply the term coupler is a joint or component holding two pipes, rotary bodies together and helping transmission of power or fluids through these pipes, shafts.
Swivel also helps one component to revolve with out turning the other. There are 90degree swivel union or elbows, swivel NPT connectors, Swivel tees. Swivels have supporting or isolating structures such as washers , bushes certain high pressure environment Swivel union also has bearings.
The Advantages Of Swivel Unions
It Seals that contain the fluid/gases in the union.
It Has no rust.
Faster to join and easier to install.
It Can be fitted with hands and is easily replaceable.
The Applications Of Swivel Unions
In joining two pipe objects.
In connecting to some Electrical Equipment.
It is Used for leak proof transfer of gases or fluids or liquids to and from the stationary supply services.
In supply of continuous brake fluid in vehicles.
To transmit coolant in Machine tools that is fixed beside the driller.