TREA

Douglas E. Johnson

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  • Webster City, IA, US
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Patents Grantslast 30 patents

  • Information Patent Grant

    Central vacuum interface for air exchanger
    • Patent number 6,218,798
    • Issue date Apr 17, 2001
    • White Consolidated Industries, Inc.
    • Tamara Price
    • A47 - FURNITURE DOMESTIC ARTICLES OR APPLIANCES COFFEE MILLS SPICE MILLS SUCT...
  • Information Patent Grant

    Central vacuum cleaner muffler
    • Patent number 6,052,863
    • Issue date Apr 25, 2000
    • Iowa State University Research Foundation, Inc.
    • Stephen P. Rittmueller
    • A47 - FURNITURE DOMESTIC ARTICLES OR APPLIANCES COFFEE MILLS SPICE MILLS SUCT...
  • Information Patent Grant

    Central vacuum with acoustical damping
    • Patent number 5,737,797
    • Issue date Apr 14, 1998
    • Iowa State University Research Foundation, Inc.
    • Stephen P. Rittmueller
    • A47 - FURNITURE DOMESTIC ARTICLES OR APPLIANCES COFFEE MILLS SPICE MILLS SUCT...