Patents by Inventor Erhard Charles Andreae

Erhard Charles Andreae has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 4008060
    Abstract: An extensible gas filter comprises three perforated walls with parallel folds, interconnected along alternate folds to allow accordion-like folding of the filter to a maximum value corresponding to the developed length of the shortest third wall, the walls defining chambers with staggered perforations forming a gas-deviating baffle.
    Type: Grant
    Filed: February 9, 1976
    Date of Patent: February 15, 1977
    Inventor: Erhard Charles Andreae