Bailey Boiler Meter - 1914

Bailey Boiler Meter - 1914

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Usage conditions apply
Ervin G. Bailey of Boston invented the type of meter shown here for the purpose of allowing hand-fired boilers to be efficiently and properly fired. His design allowed the simultaneous recording of airflow and steam flow in the boiler as a function of time. The efficient and economical operation of a boiler requires that a particular relationship be maintained between the amount of air being supplied for combustion and the amount of steam being produced. The meter shown, Serial Number 75, was one of the first that Bailey produced commercially.
The meter has a 12 inch chart face which is driven by clockwork. Three pens record data as the chart revolves. The red pen indicates steam flow while the inner blue pen indicates airflow. When the two are close together the boiler is operating at its highest efficiency regardless of the rate of steam generation. The outer blue pen indicates resistance to the flow of combustion air through the fuel bed and can indicate problems with the depth of the fuel on the fire grate and other issues. If the boiler operator keeps that pen within the shaded area on the outer edge of the chart, conditions are satisfactory.
Bailey's design for the boiler meter consists of a complex system of bells suspended over a liquid. The steam and combustion air enter under these bells and cause them to rise and fall as the pressures change. An interconnected system of rods and levers operate the recording pens. His United Stated Patent Number 1,257,965 of March 5, 1918 for a "Relation-Indicator" provides a detailed description of the design. Diagrams showing the complete design of the patent can be found in the patent document online at the United States Patent and Trademark Office website,
Bailey formed the Bailey Meter Company in 1916. The company was quite successful, becoming Bailey Controls and then Elsag Bailey Process Automation until in 1998 it was merged into ABB.
Object Name
Meter, Boiler
ID Number
catalog number
accession number
Credit Line
Gift of Bailey Meter Company, Cleveland, Ohio
Steam Engines
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Work and Industry: Mechanical and Civil Engineering
Engineering, Building, and Architecture
Power Machinery
Exhibition Location
National Museum of American History
Data Source
National Museum of American History
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