AEROGRAPHER'S MATE 3 & 2 



SWIVEL 



SNAP LINK 



(B) 



Figure 4-5. — (A) Standard psychrometer; (B) with sling attached. 



209.88: .89 



to a handcrank-operated shaft. The rotor is 

 designed for wall mounting and permits a per- 

 manent installation in the right side wall of 

 the instrument shelter. The same procedure is 

 followed in obtaining a correct reading of the 

 rotor-mounted psychrometer as was given for 

 the sling psychrometer except that the instru- 

 ment is left in the instrument shelter. 



ELECTRIC ML450A/UM 



Hand Electric Psychrometer ML-450A/UM 

 is a portable instrument used to obtain free air 

 temperature and the wet-bulb temoerature. (See 

 fig. 4-7.) 



Although the psychrometer is constructed 

 primarily of noncorrodible materials, prolonged 

 exposure to weathering, salt air, stack gases, 

 and other corrosive elements shorten the use- 

 ful life of the instrument. The instrument should 

 therefore be sheltered when not in actual use. 



The two thermometers comprising the psy- 

 chrometer have a range from plus 10° F to 



plus 110° F. The psychrometer comes with 

 a carrying case and three water bottles. With 

 the exception of the three standard flashlight 

 batteries which supply the power, it is ready 

 for operation as issued. (See fig. 4-8.) 



Maintenance 



Hand Electric Psychrometer ML-450A/UM 

 requires very little maintenance. For proper 

 operation, the instrument should be kept free 

 of dirt and other foreign matter. 



When the instrument is not to be used for 

 a prolonged period of time, remove the batteries 

 from the case because batteries will corrode 

 and damage the instrument. 



When cleaning the instrument, wash all plas- 

 tic parts with a mild soap and warm water; 

 rinse with clear water and dry. Wash the ther- 

 mometers with a mild soap and warm water; 

 rinse with clear water and dry. Wipe electrical 

 contacts with a clean lint-free cloth. If nec- 

 essary, fine sandpaper may be used to remove 



58 



