122 



STEAM BOILERS 



Frequently, pipe cover- 

 ings are made up of 

 combinations of two or 

 more of these sub- 

 stances. For pipes laid 

 in trenches, where a 

 cheap covering is de- 

 sired, such materials as 

 sawdust, charcoal, coal 

 ashes, coke, loam, and 

 slaked lime are some- 

 times used. 



Arrangement of Pi- 

 ping. The pipes and 

 fittings must be so pro- 

 portioned as to permit 

 a free flow of steam or 

 water. Water pockets 

 should be avoided; and 

 where such pockets are 

 unavoidable, they must 

 be drained to free them 

 from water. By-pass 

 pipes should be arranged 

 around feedwater heat- 

 ers, economizers, 

 pumps, etc. The sys- 

 tem must be so designed 

 as to give perfect free- 

 dom for expansion and 

 contraction. 



Perfect drainage must 

 be provided in order that 

 all water of condensa- 

 tion shall be fully sepa- 

 rated from the 

 Reliability is 

 by careful design and 

 superior workmanship, 



