Mick McCann and N. Christian Porse
June 19, 2012 | 0 Comments
In April 2012, Kingsbury Inc. and PPL Holtwood, owner of the 108-MW Holtwood plant on the Susquehanna River in Pennsylvania, celebrated the 100th anniversary of operation of the first Kingsbury bearing ever installed. This bearing, installed on Unit 5 for a test trial, proved so successful it was then retrofit on the remaining six units between 1912 and 1914 and included during installation of three new units, one in 1914 and two in 1924.
This type of bearing later became standard equipment not only for hydroelectric plants but for propellers of large ships, steam turbines and other rotating equipment. On the 25th anniversary of its operation, the bearing at the Holtwood facility was disassembled and inspected. Measurements taken indicated the remaining life of the bearing, based on wear rate, was about 1,300 years!
In 1987, the Kingsbury bearing installed on Unit 5 was designated as the 23rd International Historical Engineering Landmark by the American Society of Mechanical Engineers.
The story of the development and installation of the Kingsbury bearing at Holtwood provides an interesting historical perspective into this segment of the hydroelectric industry.
Developing the Kingsbury Bearing
The evolution of the Kingsbury company is a story of challenges and opportunities successfully met by an inventor, skilled workers, a company, as well as a history-altering thrust bearing design.
While inventors in the mechanical and electrical industries were jealously defending their patents against each other, 40-year-old Albert Kingsbury left academia in 1903 to become general engineer for Westinghouse Electric and Manufacturing Co. in East Pittsburgh, Pa. Working for Westinghouse Electric and Manufacturing put Dr. Kingsbury in touch with another of the Westinghouse family of companies, Westinghouse Machine Co., which manufactured steam turbines and mechanical stokers.
The Kingsbury family moved to Pittsburgh, the heart of industrial America, and the general engineer embraced a life of designing equipment and trouble-shooting installations. He traveled around the Northeast, building first-hand familiarity with the men and companies engaged in cutting-edge developments in electrical generation and mechanical applications. The knowledge and connections would serve him well when he ventured out on his own.
Dr. Kingsbury transitioned to independence gradually, as a consulting engineer for Westinghouse Electric and Manufacturing and Westinghouse Machine until 1913. He invoiced the Westinghouse companies $25 per day plus expenses and spent about half of his working time as a Westinghouse consultant and half on his work with the thrust bearing business.
The year 1910 was "pivotal" for Dr. Kingsbury and the pivoted shoe thrust bearing. On January 25, 1910, he received the patent for his thrust bearing design.
In the course of his travels and consulting work into the spring of 1911, Dr. Kingsbury suggested to potential customers that his pivoted thrust bearing might solve the problems they were struggling with in their roller bearings. For the next two years, he hand-wrote letter after letter to prospective buyers, patiently explaining the benefits of his bearing design:
"The design works out well for very heavy loads and slow speeds, such as occur in thrust bearings for plate glass grinding and polishing machines. The important feature of the design is the self-adjusting property of the separate sectors on which the collar slides. These sectors tip independently in their spherical seats, giving the condition required for perfect lubrication of the sliding surfaces, and thus they are able to carry unit pressures six to eight times as great as can be carried on plain collars without overheating.
The essential feature of the design lies in the ball-seated shoes or sectors, which are free to rock on their seats to make the babbitted faces conform properly to the face of the rotating shaft collar. This permits the necessary wedge-shaped oil film to form between the wearing surfaces, giving perfect lubrication."
Dr. Kingsbury exhibited a methodical approach that took advantage of his network of people in the industry. His knowledge opened doors so that potential customers at least listened and considered, even if they did not buy.
Installing the Bearing at Holtwood
The Holtwood hydroelectric plant was a vision that started in 1895 with a group of developers that purchased land along the Susquehanna River in south-central Pennsylvania. In April 1905, the McCall's Ferry Power Co. was established from the merger of two smaller hydroelectric companies, one in York and one in Lancaster counties. Construction of the plant began in October 1905 and continued until about 1908, when an economic recession bankrupted the Knickerbocker Trust Co., which was holding the construction funds, and McCall's Ferry Power had to cease work on Holtwood.
At that time, the board of directors of McCall's Ferry Power sought help from Mr. John Aldred, who was a financier and entrepreneur from the New England area. Through his connections in Canada, specifically Sir Herbert Holt, who was president of the Montreal Light, Heat, and Power Co., and Edward Wood, who was vice president with Toronto Securities, the financing package was assembled that allowed for completion of the McCall's Ferry plant.
The plant and location were named Holtwood to honor Holt and Wood, and the company was reorganized as the Pennsylvania Water and Power Co. The first unit went into service in October 1910, followed by Units 2, 3, 4 and 5 through July 1911. The plant was declared commercial in October 1911.
At the time Holtwood was designed and constructed, the turbine-generator units were some of the largest ever conceived. Reliability and equipment issues were frequent in the early year-and-a-half of operation. Roller bearings were the only available device to support the tremendous loads, but the operators were only able to get about two to three months of wear out of the bearings before having to remove the unit from service to replace components and perform maintenance.
The installation that is named as the true beginning of the business that became Kingsbury occupied Dr. Kingsbury during much of 1912 at McCall's Ferry. His relationship with Westinghouse Electric figured prominently, as the company was bidding on a hydroelectric generator for the McCall's Ferry plant but had not been asked to bid on the thrust bearing. Having had his eye on McCall's Ferry as a potential customer for two years, especially while he serviced its ailing roller bearings, Dr. Kingsbury submitted a quote on a Kingsbury thrust bearing for the installation. The price eventually settled on was $2,650 (about $61,400 in today's dollars). Westinghouse Machine manufactured the bearing, and Dr. Kingsbury paid for it with the proceeds from an insurance policy that had just matured, proud not to have borrowed money.
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