At the top of the first conveyor gallery inside the crusher house, is a head pulley on both conveyor belts. It comprises of a bare steel pulley with slots spaced along the pulley’s circumference, which serves as a grip-enhancing element, particularly when the conveyor belt is wet or dusty.
A rolled cast iron drum constitutes the centre and rotates with the pulley shaft, which is driven by a Radicon electric motor to the conveyor belt, by way of the gearbox. Mounting bolts secure the drum to the frame.
A metal mesh guard is secured for safety, to prevent workers accidentally coming into contact with any moving or working components.
Radicon DBS Gearbox
Gearboxes
Gearboxes pay an important role in controlling the speed and torque of the conveyor belt. Conveyor belts, esp those moving a heavy or full load like coal, need to operate at a slower speed in order to maximize efficiency. The gearbox efficiently transmits mechanical power from the motor to the head pulley, which in turn drives the conveyor belt. By matching the motor's output, the gearbox helps to reduce stress on the motor, which prevents it from overheating or becoming damaged from excessive loads. This also allows for precise control when reducing the speed, whilst increasing torque through a series of gears and helps prevent resistance and friction of the conveyor belt, esp when heavy loads are moving up an incline.
David Brown (DBS)
The DBS cast iron gearbox was manufactured by Radicon, who have a very long history of manufacturing gearboxes, geared-motors and drive solutions.
The DBS cover, which stands for David Brown & Sons, allows for maintenance access, with fins on the side designed to dissipate heat.
David Brown was born in 1839 and opened a small pattern-shop in Yorkshire, Northern England, in 1860. He became focused on gear systems in 1873, which led to producing machine-cut gears in 1898.
A year after his death in 1903, his grandson was born (also called David Brown), who would later become Managing Director of the company in 1931. The company flourished under his leadership, pioneering military gear systems, including tank transmissions during WW2. They launched their own tractors in 1936 and acquired Ashton Martin in 1947, which gave rise to the famed DB series of car that was featured in James Bond movies. They continued to grow, diversifying with ship building.
Sir David Brown was knighted in 1968 for his services to the industry. Shortly after selling off the car division and tractor operations in 1972, he stepped down from his role into retirement until his death in 1993.
Fan-Cooled Induction Motors
Fan-cooled induction motors in the coal house were used to power the conveyors.
Photo 1 - Heavy cast-iron body with a fine steel mesh cover on the endbell. It’s installed on a large footplate that’s bolted on a raised base. The fine mesh protects the internal fan and windings from dust, more so than a coarse mesh cover.
Photo 2 - The wider course mesh on Radicon’s endbell allows more airflow than the one in the first image.
Radicon is a brand that’s well known for their gearboxes and motors drives. It’s very likely this unit was connected to the geared drive motor or maybe directly-coupled to a reducer, to give the conveyor or the rotary valves more torque.
Due to my limited knowledge and experience with gearboxes, let alone anything mechanical, I can only ascertain the individual components at this stage.
Motors like this tended to be manufactured between 1930-1950 but with the coal house being constructed in 1956, it’s safer to go with the later date category.
LSE Conduit Box
This old cast iron conduit box housed electrical connections and was bolted down onto the gearbox.
Armoured cables with metallic conduit fittings are common in industrial settings, like power stations, mills and mining processing plants.
LSE stands for London Small Electricals (LSE Ltd), who were a British manufacturing company. Their conduit boxes were commonly installed during the early-to-mid 20th century, in UK and Commonwealth electrical infrastructure.
They manufactured junction and switch boxes, specialising in the requirements of factories and power station facilities.
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The Earlier Process
Coal was delivered to pulverising mills located in the basement of the boiler house, where it was ground into an extremely fine powder. It was so fine, that around 80% could pass through a mesh with 200 openings per square inch.
From there, exhaust fans transported the pulverised coal to the furnace burners supplying the station’s four boilers. The fine coal was blown directly into the furnace, where it ignited instantly.
To initiate the combustion process, the burners were first lit using oil-fired jets. Once the coal caught alight, the oil supply was shut off.
Head Pulley
