Tsubaki engineering class SJ3 sealed joint chains, with improved sealing technology, are designed to improve the reliability of many mechanical components exposed to harsh conditions in coal mining.

Available from industrial engineered products and components manufacturer BMG, Tsubaki’s patented SJ3 labyrinth structure keeps each pin and bushing assembly free and clear of contaminants.

“This multi-seal combination inhibits fine particulates from entering critical bearing areas. As a result, the risks of premature elongation, joint lockage and dry cavitation are reduced, allowing for more effective chain performance and longer life,” says BMG Tsubaki national product manager Marthinus Janse van Rensburg.

He explains that the Tsubaki SJ3 design comprises three distinct seals. Although independent of one another, the seals complement each other to provide secure bushing and pin protection. The first seal is an industry standard extended bushing, that limits the clearance between the ends of the bushings and the mating sidebars. This provides a highly effective first layer of protection.

“The second seal is a polymer face seal placed around the extended bushings. These polymer face seals are available in various performance materials and can withstand temperatures up to 204 °C. The final seal is a patented labyrinth seal that inhibits any remaining fine particles from entering the critical bearing area. The labyrinth is formed by a stainless steel ring attached to the pin, which rotates freely in a finely crafted groove in the bushing.”

The user of a carbon coke bucket elevator initially installed a non-sealed elevator chain that lasted 12 months and then a non-sealed chain with hardened stainless steel pins, which lasted double that period. The lifespan of the chain increased to 56 months after the installation of a Tsubaki SJ3 chain.

The chain of a potash feeder, with packed joints that kinked and eventually failed, was replaced with a Tsubaki SJ3 chain with stainless steel pins, and component lifespan trebled.

In a fly ash bucket elevator, the standard elevator chain lasted about 12 months. Service life of the chain has increased to more than 36 months since the installation of Tsubaki SJ3 chain.

BMG’s durable Tsubaki SJ3 series has been designed for dependable operation in harsh environments, including mining, cement, paper, sugar, grain and asphalt applications.

BMG’s total plant management solutions encompass a technical advisory service on correct chain selection – a critical factor in any power transmission system. The complete range of Tsubaki power transmission components is available from BMG’s national branch network, which offers a 24-hour back-up service.