MONITOR VENTILATORS. 



3*9 



flashing-' 



Hinge 



-Bracket aftachecf to frame 



160. HINGED MONITOR SHUTTER. 



Details of a hinged shutter are shown in Fig. 160. The angle iron 

 frame is covered with a corrugated iron covering. The shutters are 

 made from 6 to 10 feet long, with two hinges for shutters 8 feet long 

 and three hinges for shutters more than 8 feet long. Where shutters 

 are to be glazed they are hung as in Fig. 156. The lever gear shown 

 by the dotted lines is used in the better class of structures. This device 

 can be used where the shutters are glazed if care is used in operating. 



In smelters the clerestory of the monitor is often left entirely open 

 or is slightly protected by self acting shutters. In the latter case the 

 shutters are hinged at the bottom and are connected at the top with each 

 other and with a counter-weight so that the shutter will ordinarily make 



