PRINCIPLES OF NAVAL ENGINEERING 



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38.45 

 Figure 11-4.— Cutaway view of cyclone steam 

 separator. 



BAFFLE 



STEAM 



INLET 



WATER 



38.46 

 Figure 11-5.— Plan view of cyclone steam 

 separator. 



Before reinstalling the fittings, wirebrush, 

 clean, and hose down the steam drum. Be sure 

 that it is clean and free of any oil or other 

 accumulation. 



When replacing the fittings in the steam 

 drum, be sure that all the bolts are drawn tight. 

 The desuperheater flanges must be thoroughly 

 cleaned before the desuperheater is fitted into 

 place and bolted. New gaskets must be installed. 

 The flanges must be drawn up evenly and tightly 

 to prevent any leakage from the flanged joints. 



The internal fittings used in newer single- 

 furnance boilers differ from those used in older 

 boilers and also differ among themselves. Fig- 

 ure 11-7 shows the arrangement of fittings used 

 in the steam drum of a boiler on a DLG 9-15 

 class ship. A little study of this illustration 

 shows several new or different features. 



To begin with, notice that there is no desu- 

 perheater, even though this is a single-furnace 

 boiler. The boiler does have a desuperheater, 

 but it is installed in the water drum rather than 

 in the steam drum. 



Another interesting feature illustrated in 

 figure 11-7 is the vortex eliminator. A vortex 

 eliminator consists of a series of grid-like 

 plates arranged in a semicircular shape to con- 

 form to the shape of the lower half of the steam 

 drum. One vortex eliminator is located at the 

 front of the steam drum (as shown in fig, 11-7) 

 and another is located at the rear of the drum. 

 In each case, the eliminator is fitted over the 

 necks of the downcomers. The purpose of the 

 vortex eliminators is to reduce the swirling 

 motion of the water as it enters the down- 

 comers. 



The arrangement of internal fittings in the 

 steam drum of a boiler on one of the newer de- 

 stroyer escorts is shown in figure 11-8. Notice 

 that there are two feed pipes, each of which runs 

 lengthwise in the drum. The discharge holes are 

 drilled along the inner side of each feed pipe so 

 that the incoming feed water is discharged hori- 

 zontally toward the middle of the drum. Notice 

 also that the internals in this steam drum in- 

 clude horizontal steam separators rather than 

 cyclone steam separators. 



A horizontal steam separator is shown in 

 figure 11-9. These separators are installed in 

 much the same way as the cyclone steam sepa- 

 rators—that is, one row of separators is in- 

 stalled along each side inside the steam drum. 



Each horizontal steam separator has a ma- 

 chined flange which is bolted to a matching flange 

 attached to a girth baffle. The mixture of steam 



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