This valve was made by the American rocket pioneer Dr. Robert H. Goddard (1882-1945) to protect his liquid oxygen tanks from bursting due to too much pressure caused by evaporation of the very cold liquid. The valve dates to the 1930's when Goddard conducted his experiments at Roswell, New Mexico.
Mrs. Robert H. Goddard donated this object to the Smithsonian Institution in 1959 as part of a large collection of artifacts from her husband.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.