Patent ID: 8863974

Claim:
A support column assembly for supporting a floating roof defining a generally horizontal plane that is used as a top closure for a storage tank, comprising: a. an inner pipe formed by a cylindrical wall having top and bottom ends and having a central longitudinal axis therethrough, b. an outer pipe securable to said floating roof whereby it will to extend below and generally perpendicular to the plane of said roof, said outer pipe formed by a cylindrical wall having top and bottom ends and having a central longitudinal axis therethrough, said outer pipe surrounding and being movable axially with respect to said inner pipe between different predetermined axial locations relative to said inner pipe, and with a generally annular space defined between said inner and outer pipes, said generally annular space having opposite top and bottom ends, c. a first set of coaxial holes extending generally perpendicularly to said central longitudinal axis thereof and through opposite sides of said wall of said outer pipe, d. a second set of coaxial holes extending generally perpendicularly to said central longitudinal axis thereof and through opposite sides of said wall of said inner pipe, e. said first and second sets of holes dimensioned to receive a pin extendible generally perpendicular to said central longitudinal axis of said pipes and through both sets of holes at once when said outer pipe is at a selected one of said predetermined axial locations relative to said inner pipe and said first and second sets of holes are axially aligned, and f. a primary seal formed as an elastic cylindrical sleeve having upper and lower parts each with bore surfaces, said upper part bore surface being adapted to slidably engage said inner pipe outer surface, and said lower part bore surface adapted to resiliently engage said top end outer surface of said outer pipe, said primary seal further comprising a radially inward extending rib situated axially between said upper and lower part bore surfaces and extending transversely across and closing said top end of said annular space when said primary seal is positioned to engage said inner and outer pipes.