ASME-Landmark:Gravimetric Coal Feeder


A variety of mechanical feeders, including drag-chain conveyors and rotary pocket feeders, were historically used to volumetrically control the flow of fuel to coal pulverizers on power generators. Most power generation in the United States has relied on burning fossil fuels in steam boilers, with coal as the fuel of choice. By the 1920s, pulverized-firing (the burning in suspension of finely ground coal particles) evolved as means to more complete fuel combustion and higher system efficiencies, which facilitated the use of larger boilers.

In the 1950s, Arthur J. Stock (1900-1986) successfully combined the weighing and control of material flow into a single device, now known as the gravimetric feeder. The first installation was placed in continuous operation at Niagara Mohawk Power Corporation's Dunkirk Station in 1957.

Ralph Hardgrove, a Babcock & Wilcox retiree who joined Stock Equipment Company in 1961 (at 70 years of age), led the feeder's development into general industry acceptance by the mid-1960s, when most large coal-fired boilers included gravimetric feed systems in their design.

The first Stock gravimetric feeder was manufactured and installed in 1957 and operated until 1992, at which point it was replaced by the more modern gravimetric microprocessor-controlled design. This feeder, the earliest known in U.S. history, was donated to Stock Equipment, refitted, and refurbished for public display in the Stock Equipment Company's modern-day headquarters in Chagrin Falls, Ohio. See ASME website for more information