326 



VENTILATION 



Furnaces are generally provided with water pans, set in the 

 casings, but they usually have little value as humidifiers. 

 Any device used as a humidifier which will not readily evapo- 

 rate 1 or 2 qt. of water per hour, in a well- ventilated residence 

 having 6 or 8 rooms, is inadequate when used anywhere in the 

 United States north of the 40th parallel of latitude. Most 

 furnaces are so constructed that it is possible to equip them 

 with a more nearly adequate humidifier easily and at slight 



expense. Figure 232 shows 

 how such a humidifier may 

 be installed in a furnace by 

 any furnace setter. A large, 

 seamless galvanized iron or 

 copper pan filled with clean 

 sand is set on the top of the 

 radiator of the furnace in- 

 side the casing. A galva- 

 nized iron pipe is passed 

 through the casing. The 

 inner end of this pipe is di- 

 rectly over the center of the 

 pile of sand. The outer end 

 of the pipe carries an "el- 

 ,, bow," turned so as to open 



FIG. 232.-Humidifier. Upward. A Supply pipe 



(leading from the water 



system or from a supply tank) equipped with a valve for 

 regulating the flow, is so adjusted that water drips into the 

 upturned elbow. The operator can see exactly how fast the 

 water is being supplied, and the amount delivered by the supply 

 pipe per hour can be determined at any time. 



Such a humidifier is nearly automatic in its operation. The 

 sand forms a reservoir which is capable of holding a large 

 amount of water. But it is evident that the sand becomes 

 heated when the fire is burning up freshly. This heated sand 

 then continues to evaporate water even when the fire has died 



