Carhart Balanced Valve, Patent Model

This model was submitted to the U.S. Patent Office with the application for the patent issued to John W. Carhart, of Troy, New York, March 27, 1866, no. 53410.
The model represents a conical plug valve with an annular exhaust space between the plug and the valve and a steam passage through the hollow core of the plug. The peculiar feature of the valve is the provision of recessed annular spaces in the valve, which, with the valve seat, form small pistons and cylinders designed to balance the valve longitudinally when connected to the steam passages. Screw adjustments on the valve stem and the small end of the valve are provided for setting the valve in a position giving proper contact with the minimum of friction.
This description comes from the 1939 Catalog of the Mechanical Collections of the Division of Engineering United States Museum Bulletin 173 by Frank A. Taylor.
Currently not on view
Object Name
balance valve, model
patent model, valve, steam engine
date made
patent date
Carhart, John W.
Physical Description
brass (overall material)
wood (overall material)
valve - from catalog card: 2 1/2 in x 6 in; 6.35 cm x 15.24 cm
overall: 3 3/4 in x 6 in x 2 1/4 in; 9.525 cm x 15.24 cm x 5.715 cm
place made
United States: New York, Troy
associated place
United States: New York, Troy
ID Number
accession number
catalog number
patent number
Engineering, Building, and Architecture
Industry & Manufacturing
Bulletin 173
See more items in
Work and Industry: Mechanical and Civil Engineering
Bulletin 173
Data Source
National Museum of American History, Kenneth E. Behring Center
Related Publication
Frank A. Taylor. Catalog of the Mechanical Collections of the Division of Engineering United States National Museum, Bulletin 173

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