Sturtevant’s Patent Model of a Compound Air-Heater and Steam-Condenser – ca 1870

Sturtevant’s Patent Model of a Compound Air-Heater and Steam-Condenser – ca 1870

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This model was filed with the application to the U.S. Patent Office for Patent Number 100,242 issued to B.F. Sturtevant of Jamaica Plain, Massachusetts on February 22, 1870. The patent was for an improvement in compound air-heaters and steam-condensers.
The primary elements of the patent were a centrifugal fan, a heat exchanger case and associated ductwork. The fan (based on a previous patent by Mr. Sturtevant) drew air through the heat exchanger and was intended to exhaust the heated air into distribution ductwork. The heat exchanger consisted of an inner cylinder enclosing a large number of horizontal air tubes. Steam was introduced into the cylinder via a nozzle at the top. Steam and water condensed from steam within the cylinder exited via a like nozzle at the bottom. Plates at each end sealed the cylinder to prevent steam escaping while allowing air to flow through the tubes.
Mr. Sturtevant claimed as new and improved his concept of providing an outer cylinder that enclosed the inner. This increased efficiency by causing air to flow both over the heated inside and outside surfaces of the inner cylinder. He also increased efficiency by placing deflector plates inside the steam nozzles to improve the distribution of steam across the air tubes and also to reduce the splashing of condensate at the exit. He provided for improved access for cleaning and repairs by including space between the fan housing and the heat exchanger and providing removable panels.
Sturtevant enjoyed significant commercial success with this and his other patents (no less than 10 patents dealing with heating and ventilation were granted to him on the same day as this patent). In 1860 he founded the B. F. Sturtevant Co. which was extremely successful and long lived; Westinghouse bought the company in 1945, and operations continued at the Hyde Park, MA factory until its closing in 1989. The company’s equipment was installed in many public and private buildings including the U.S. Capitol and the “New National Museum, Washington, D.C” – now the Smithsonian National Museum of Natural History.
The patent model is shown in the image. The model is highly detailed and is constructed of metal castings and brass plate. It illustrates most of the key elements of the patent to include the details of the steam nozzles, deflector plates, and the provisions for access for maintenance. Diagrams showing the complete design of the heater can be found in the patent document online (
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Object Name
air heater and condenser, model
patent model, condenser, steam & air heater
date made
ca 1870
ca 1870
patent date
Sturtevant, B. F.
place made
United States: Massachusetts, Boston
associated place
United States: Massachusetts, Boston, Jamaica Plain
overall: 11 1/2 in x 10 in x 15 1/2 in; 29.21 cm x 25.4 cm x 39.37 cm
ID Number
accession number
catalog number
patent number
Patent Models
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Work and Industry: Mechanical and Civil Engineering
Patent Models
Engineering, Building, and Architecture
Data Source
National Museum of American History
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