Patents Examined by Asko Pal
  • Patent number: 5009715
    Abstract: A method and apparatus for cleansing the upper interior surfaces of a concrete sewer conduit, the apparatus including the concrete sewer pipe and a plurality of spray nozzles spaced apart and adapted to be introduced into and disposed in and along a length of concrete sewer to enable continuous or intermittent spraying of the upper interior surface or, alternatively, to be permanently mounted along the length of the concrete sewer conduit when newly constructed.
    Type: Grant
    Filed: November 20, 1989
    Date of Patent: April 23, 1991
    Inventor: R. E. Wilson