SANITARY PLUMBING 



501 



What effect does heating water have upon its volume? What 

 is the effect upon its density (Ex. 11)? What is the cause 

 of convection currents (Art. 135)? The circulation of water 

 through the heater is just as truly due to convection as the 

 circulation of air through a furnace and the furnace pipes. 

 Why is it best that the cold water supply pipe should extend 

 nearly to the bottom of the 

 boiler? In which portion of the 

 boiler is the water the hotter, 

 the bottom or the top? Why? 



589. The Faucet or Bibb. 

 There are many different styles 

 of FAUCETS, or BIBBS, as the 

 plumber calls them. The FUL- 

 LER FAUCET is a common type 

 (Fig. 309). The figures show its 

 construction and how it works. 

 After being used for some time, 

 especially if used on a hot water 

 system, the rubber ball is likely to 

 become softened and expanded, 

 thus interfering with the flow of 

 the water. New balls are easily 

 inserted by anyone handy with 

 tools. Most types of faucets 

 occasionally need slight repair. 



Faucets used in hotels, public places, and especially in 

 schoolhouses, are often of the SELF-CLOSING type (Fig. 310). 

 This is a modified form of the common COMPRESSION FAUCET. 

 As is the case with any compression faucet, a right-handed 

 tread on the post lifts the valve from its seat when the handle 

 is turned counter-clockwise- But in this faucet a stiff spiral 

 spring surrounding the post is thereby compressed. As 

 soon as the pressure upon the handle is removed, this spring 

 forces the valve down again upon its seat. What is the advan- 

 tage of a self-closing faucet? 



FIG. 308. The water front and 

 its connections with the boiler. 



