Steam Tube Dryer Rotary Joint Reliability: A Tale of Two Dryers
Rotary joints provide a reliable seal between fixed piping and rotating components. Whether it is with steam, water, thermal oil, or any other fluid, we have found that many rotary joint installations have deficiencies that lead to premature operating life and an increase in maintenance frequency.
Deviation from recommended practices can have significant negative impact on equipment reliability, process uptime, and overall dryer efficiency. Steam tube dryers can present several unique conditions that make proper installation a critical element of good equipment performance and drying efficiency.
Runout Requires Special Considerations
In one case, we worked with a food processing company in the Southern U.S. who was experiencing significant dryer runout on its large grain dryer which was leading to unreliable rotary joint performance. The plant determined that eliminating the runout was not feasible in the short term.
To address this unique operating condition, we identified a potential solution that included a self-supporting rotary joint, properly sized flexible metal hoses, an anti-rotation rod and support brackets. Layout drawings showing the equipment needed and the proper method of installation were provided by Kadant Johnson and the plant contracted a local firm to remove the existing equipment and install the new equipment per the recommendation.
After completing the upgrade, the plant immediately realized the benefits of a proper installation that restrains the rotation of the rotary joint but allows for the rotary joint to follow the runout of the dryer. Since the reconfigured installation, the plant has eliminated downtime associated with the rotary joint and flexible hose failures on this steam tube dryer.
Properly Designing Anti-Rotation Rods
In another case from the same company, but at a different location, a grain dryer was experiencing premature flexible hose failure and unscheduled maintenance. A quick review by Kadant Johnson found the plant’s design of the anti-rotation rod and support was inadequate to prevent dryer torque from being translated to the flexible hose.
Similar to the previous case, Kadant Johnson provided layout drawings showing the equipment needed to adapt to this dryer, including a design for an anti-rotation rod and rod support bracketry. After start-up, it was immediately evident the properly designed anti-rotation rod successfully eliminated the torque from being transferred to the flexible hose. This upgrade increased flexible hose life and significantly reduced unscheduled maintenance.
To realize this cost-effective solution, the Field Service team from Kadant Johnson made a relatively brief on-site visit to observe the installation and operation, and then provided a well-defined and practical solution that was easily implemented by the plant.
Maximum operating life of the rotary joint begins with the proper installation using the proper rotary joint, flexible hoses, and anti-rotation devices. Over time, a rotary joint installation that follows the recommended guidelines for installation, maintenance, and repair leads to less unplanned maintenance downtime, increased reliability, and maximum drying performance.