Background:
A U.S. electric power utility company seeking to rapidly recommission a dormant, coal-fired power plant faced the challenge of modernizing the plant’s existing equipment including their coal railcar dumper. The railcar unloader was equipped with an existing disc brake and thruster, but both components were severely deteriorated due to their age and use in the harsh environment. For instance, the thruster disc brake’s torque spring assembly and stroke adjustment mechanism were among several components that were rusted, clearly unsafe for continued use, and lacking basic identifying information including a nameplate. Furthermore, in addition to restoring the brake assembly to make it suitable for continued use, the customer also needed to ensure the brake assembly was appropriately rated for use in the explosion proof (coal dust) environment. Given the urgent need for reliable support, the utility sought Hindon’s expertise to quickly investigate the existing industrial braking system’s issues and recommend a solution.
Deteriorated explosion proof brake and thruster in a dormant coal-fired power plant
Under normal conditions, the plant’s operational environment consists of an explosive atmosphere, consisting of a mixture of air and flammable substances in the form of coal powder and dust. In these types of atmospheric conditions, passive protection technology with adherence to national/international standards is required.
A rotary car dumper is a mechanism used for unloading railroad cars in industrial applications.
Application Challenges:
- Urgent need for a new brake assembly to restore operations swiftly
- Requirement for an explosion-proof rating suitable for a coal dust environment
- Lack of technical information relating to the existing brake assembly
Solution:
Recognizing the time sensitivity of the situation and the condition of the existing brake and thruster, Hindon recommended replacing the entire brake assembly rather than attempting to repair individual components. Hindon engaged in a detailed technical consultation to confirm and clarify the explosion-proof requirements, identifying the specific IECEx/ATEX Zone 21 designation for coal dust, which is critical for safety in such environments. Leveraging its comprehensive understanding of industrial braking systems, Hindon suggested an Explosion Proof rated replacement thruster disc brake assembly and provided all possible options for expediting its delivery.
Hindon’s solution featured an explosion-proof, spring-applied, electrohydraulic thruster-released disc brake. The brake’s release thruster was engineered, tested, and inspected for safety in hazardous environments, featuring a robust cast iron housing and advanced explosion-proof seals. A precisely engineered flame path, manufactured to tight tolerances, contains internal explosions, forcing them to extinguish long before they reach the threshold for external ignition. These thrusters are designed for longevity and reliability, using heavy duty corrosion-resistant construction to preserve the flame path for the life of the thruster. The design also eliminates potential failure points such as gaskets and incorporates a secure, fully contained electrical connection, isolating the terminal box. This comprehensive approach ensures the explosion-proof thrusters exceed safety standards, providing reliable performance in demanding applications.
Another key feature of the disc brake assembly include sintered linings, known for their superior performance and durability in demanding industrial applications, especially in environments with high temperatures or heavy duty cycles like those found in a power utility. Additionally, the brake was also equipped with an ATEX-approved limit switch for indicating “brake released.”
Despite the initial information constraints, Hindon’s ability to quickly assess the application and specify a compliant, robust, and readily available solution underscored its capabilities as a responsive and knowledgeable supplier. By delivering a tailored explosion-proof braking system within an expedited timeframe, Hindon ensured the utility could resume operations safely and efficiently in line with their expedited project timeline.