Basics of a Continuous Caster Rotary Union
Cooling water that passes through continuous casting machine rolls used in the steel industry is typically 90°F (32°C) at the inlet and approximately 120°F (49°C) at the outlet of the roll. The water pressure is usually 120psig (8.2 bar) and the rotational speed typically less than five RPM.
For cooling water to pass through the caster rolls, a rotary union is required to allow the cooling water to enter and exit the rolls that support the strand of steel as it is solidifying. These rotary unions, referred to as C-Cast™ rotary unions, incorporate a simple design with an innovative sealing technology.
The rotary union uses DuraSeal™ technology to provide the rotary sealing action. The seal used in this application is similar to an O-ring, but has a unique cross-section that enhances the sealing capability. This shape gives increased reliability over a standard O-ring when used as a dynamic seal.
C-cast rotary unions can be either through-flow or dual-flow and are most commonly self-supported and mounted directly to the end of each roll. The most common sizes are ¾” and 1” while some applications require a 1.5” size. For corrosion prevention, the body is made from a bronze material and the nipple is stainless steel.
There are two different styles of these rotary unions: journal-inserted and an externally-mounted threaded version. The journal-inserted design is intended for installation into the roll journal and reduces the space occupied by the rotary joint. The journal-inserted version is typically installed on continuous casting machines and is the more common of the two styles.