Abstract: A process for manufacturing an improved flight assembly for a vertical centrifugal separator. e.g., of the type used to dry coal, is disclosed. The flights are first welded to the cone on which they are to be carried, then the outside edges of the flights are machined, for example on a vertical mill, after which a hard facing is applied to at least a portion of each flight. Preferably a stabilizing ring is welded to the bottoms of the flights before machining. A machining tolerance of plus or minus 1/64 inch (with respect to the gap between each flight and the surrounding conical screen with which the flight assembly is to be used) is preferred. The hard facing may be a weld having a hardness of at least about 40 Rockwell (C scale).

Abstract: A vertical centrifugal separator, for example of the type used to dry coal, is improved by splitting the frustoconical screen into two pieces and including access doors in the water shield surrounding the screen. The division of the screen is made horizontally, for example at a level of about 30 to 70 percent down from the top of the screen. This permits the separator to be serviced in a relatively short time, by replacing only the upper partial screen when holes are worn in it. This is feasible because most of the wear in these screens is confined to about the upper 30 percent of their height. If a screen support basket is used, it can be confine to the lower partial screen, so that it does not have to be removed in order to replace the upper partial screen.

Abstract: Flush type floor box including a flat floor plate assembly having a pair of caps which cover a duplex receptacle. For access to the receptacle the caps are pried up and swung away by using a tool such as the tip of a screwdriver. The floor plate can be adjusted vertically and tilted in a vertical position so as to be level or flush with the floor surface either at the time of the pour or after the concrete has hardened.