Abstract: A sealing system for heat exchangers of the type having a plurality of vertically positioned heat tubes extending through a heat tube sheet for exchanging heat between the interior of the plurality of heat tubes to the surrounding atmosphere, the sealing system including a first outer ring having a wall portion, terminating in an upper face, and defining an annular space between the lower end portion of the outer ring and the heat tube and tube sheet; a high nickel metal inner ring, positioned within the annular space surrounding the heat tube and resting on the tube sheet; a soft metal casing partially housing the high nickel inner ring so that when force is applied downward on the first outer ring, the annular space is reduced sufficiently to force the high nickel ring and the soft metal casing into a sealing relationship between the heat tube and the tube sheet, while allowing for vertical movement of the heat tube; the outer ring further defining a means to prevent the high nickel ring and the soft metal

Abstract: An unloading valve for hopper cars used for transporting dry fluent material such as carbon black. An unloading pipe extends outwardly from the bottom of the hopper, and a closure removably attaches at the end of the pipe. The closure includes a plug extending within the pipe and presenting a surface that confronts the dry fluent material adjacent the inner end of the pipe. This surface has an angle selected to cause fluent material loaded into the hopper to become packed at the inner end of the pipe during loading and subsequent shipment of the hopper car. When the closure is removed for attaching an unloading conduit to the pipe, the packed material at the inner end of the pipe prevents any of that material from leaking out the pipe before the unloading conduit can be connected.