Conduits having a shock absorbing shell and method for their formation
AssigneeProgressive Polymerics, Inc.
InventorFrederick L. Griffith
Life of this patent
Estimating the term…
Abstract
In accordance with the invention, a concrete conduit is completely encased within a shell of a plastic resin such as polyethylene. The plastic shell functions to insulate the concrete conduit from mechanical shocks thereby preventing breakage and cracking of the conduit. The shell also effectively provides an impermeable barrier for water vapor and a smooth, relatively frictionless, surface for receiving electric cables, wires and the like. The conduit is made by preforming the shell, for example by rotational molding, and filling the shell with pourable cement through a filler hole in the shell. The filler hole can then be closed with a plug of the resin used to form the shell.
Claims17
An elongated conduit segment which is suitable for coupling in end-to-end fashion with another conduit segment, comprising:
- an elongated concrete material tubular member having an inner surface, an outer surface and a bore extending in a longitudinal direction between open ends thereof;
- and a plastic, elongated conduit segment shell, which is resistant to deformation and which covers said inner surface and at least substantially all of said outer surface to help insulate the tubular member from mechanical shocks, the conduit segment shell being characterized by a longitudinally disposed bore therethrough between two open ends thereof, with the bore of the conduit segment shell being situated within the bore of the concrete tubular member, and the conduit segment shell being further characterized by a neck region at each of its open ends.
An elongated conduit for housing electric cables comprising a plurality of conduit segments coupled end-to-end, each conduit segment comprising:
- an elongated concrete material tubular member having an inner surface, an outer surface and a bore extending in a longitudinal direction between open ends thereof;
- and a plastic, elongated conduit segment shell, which is resistant to deformation and which covers said inner surface and at least substantially all of said outer surface to help insulate the tubular member from mechanical shocks, the conduit segment being characterized by a longitudinally disposed bore therethrough between two open ends thereof, with the bore of the conduit segment shell being situated within the bore of the concrete tubular member, and the conduit segment shell being further characterized by a neck region at each of its open ends.
Dependencies are inferred from the claim text.