a cap nut which protects the threads from possible oxidization. The joints 

 between header and handhole plates are made with thin gaskets. 



Cores ordinarily made of No. 13 B. W. G. tubes, plugged at one end, are 

 inserted in the straight portion of the 2-inch superheater tubes, causing the steam 

 to flow through the annular space thus 



n formed. By a variation in the diameter 



of these cores, the proper ratio of total 

 cross sectional area through the tubes 

 to that through the boxes may be 

 secured. The cores are held central 

 in the superheater tubes by projections 

 formed in the cores for this purpose. 

 This construction is clearly shown by 

 the illustrations. The cores are main- 

 tained in their position lengthwise in 

 the superheater tubes by similar pro- 

 jections which engage grooves rolled 

 for the purpose in the tubes near their 

 lower ends. 



One end of each superheater 

 header is welded closed. To the other 

 end there is attached a wrought-steel 

 flange. The pipe and flange are 

 threaded, the pipe slightly expanded 

 after the flange is screwed on, then 

 peened over and faced. 



Steam is taken through the boiler CO RES FOKINSTAL- 

 dry pipe from the saturated steam LATION IN SUPER- 

 COLD DRAWN SEAM- HFATFR TITRFS 

 LESS STEEL SUPER- outlet on the center drum by means 



HEATER TUBES of tubes expanded at the ends into 

 wrought-steel flanges. A special 



cast-steel flanged inlet elbow connects the intake pipe to the intake superheater 

 header. The steam then passes through the tubes to the outlet header, to 

 the flanged end of which is a special cast-steel superheated steam outlet fitting. 

 This fitting has a standard extra heavy flanged outlet to which the superheated 

 steam connection from the boiler is made. The superheater outlet fitting 

 also has an extra heavy flange for the reception of a safety valve. The safety 

 valve which is furnished as a part of the regular superheater equipment is steel 

 bodied, of the outside spring type, and is set to blow at a pressure slightly lower 

 than that at which the saturated steam safety valves of the boiler are set. 



The inlet and outlet superheater fittings are provided with square handholes 

 which give access to the ends of the superheater headers and to the inlet 

 and outlet connections. These handholes are closed by square, inside fitting, 



59 



