Heat pipe heating system for a railway tank car or the like

Claim 1

A railway tank car comprising a tank shell having ends to form an enclosure for carrying lading, a heat transfer pipe mounted on the tank car having an inner end portion extending within the tank shell and an outer end portion extending outwardly of an end of said tank shell, and heat producing means mounted on said railway tank car outwardly of said shell to heat said outer end portion for the transfer of heat therefrom to the portion of the pipe within the shell and a subsequent transfer of heat to the lading within the shell, said heat transfer pipe comprising an outer enclosed casing extending axially generally in the direction of the longitudinal axis of the car at a slope of at least 2 percent with respect to the longitudinal axis of the railway car, a porous wick positioned against the inner circumferential surface of the casing at least within the outer end portion, a vaporizable fluid within the casing, said fluid being vaporized by the heat generated by said heat producing means and moving away from said heat producing means to said inner end portion, said vaporized fluid condensing along the length of the heat transfer pipe within the tank shell and returning to the outer end portion by a capillary action of said wick, and a closed sump reservoir of a large cross-sectional area relative to said casing being outside the tank shell and connected to the bottom of said outer end portion of said pipe for draining off and storing the vaporizable fluid when said heat producing means is not in operation, said wick extending along a wall of the reservoir immediately subjacent the heat pipe to the bottom of the reservoir whereby the vaporizable fluid may be drained from said reservoir into said pipe by a capillary action, said reservoir having a sufficient capacity to prevent damage to said heat pipe due to freezing of the vaporizable fluid.