FLASK FOR DETERMINATION OF WATER IN FLOUR AND MEAL. 



"T" 



STOPPERS TO BE USED. 



If copper flasks ai»e used, a special No. 5 rubber stopper wiU have 

 to be made, so as to stand the high temperature. Figure 7 shows the 

 results of the heat on three rubber stoppers when run in a double- 

 walled copper flask. The temperature of the oil 

 in the inner flasks in each of these tests was 190° 

 C. when the flame was extinguished. Stopper A 

 was made especially to stand high temperatures and 

 was tested once ; stopper B was also especially made 

 by the same manufacturer who made stopper A, but 

 was tested 30 times, while stopper C is the regular 

 No. 5 stopper and was tested only once. It is im- 

 portant that a special stopper which will stand high 

 temperatures be used if flour and meal are run in 

 the copper flask. 





HOW TO TEST DIFFERENT SUBSTANCES. 



The methods used in testing flour and corn meal 

 are as follows : 



Wheat flour. — Use 150 c. c. of oil both in the 

 inner flask and between the two walls and 50 

 grams of flour in the inner flask. Extinguish the 

 flame when the temperature reaches 190° C. The 

 oil in the inner flask should reach 190° in about 

 30 minutes. 



Corn meal. — Use 150 c. c. of oil both in the 

 inner flask and between the two walls and 50 

 grams of corn meal in the inner flask. Extin- 

 guish the flame when the temperature reaches 

 175° C. The oil in the inner flask should reach 

 175° in about 26 minutes. 



—14 



=lg 



HQ 







A.. 



Fig. 4.— G raduated 



measuring cylinder, 

 showing 13.2 per cent 

 of moisture. 



TIME OF TEST. 



One of the most important factors 

 in getting correct results in the test 

 here described is the time in which it is made. Unless the 

 flame is under the direct control of the operator and run 

 in accordance with the following directions, the test will 

 not be accurate. 



The flame should be so adjusted that the temperature 

 of the oil in the inner flask will reach 120° C. in 15 minutes 

 and rise approximately 5 degrees for every minute after 

 that until it reaches the desired temperature. This wiU require 14 

 minutes for oil containing flour after it gets to a temperature of 

 120° to reach a temperature of 190°, and 11 minutes for oil contain- 

 ing meal after it gets to a temperature of 120° to reach a tempera- 

 ture of 175°. If the oil in the inner flask reaches a temperature of 



Fig. 5.— Test 

 tube cleaner. 



