12 BULLETIN 569, U. S. DEPARTMENT OF AGRICULTURE. 



likely to be compensated for by the carefulness of the other sorters 

 than in the case of any of the other systems. This, however, should 

 not be used as an excuse for putting unreliable sorters on the apron. 



The width of aprons used varies greatly, ranging from 8 inches to 

 4 feet. To get the best results the aprons should be narrow enough 

 for the sorters to reach easily across the entire width. The most 

 convenient and practicable width has been found to be from 18 to 20 

 inches. 



Even greater variation is found in the rate of movement of the 

 apron. Tests on the rate of speed in different plants showed a mini- 

 mum rate as low as 16 feet per minute and a maximum as high as 

 140 feet. The speed of the apron should be retarded sufficiently to 

 permit careful observation of the individual tomatoes and to allow 

 the sorters sufficient time to reach for and remove those with rotten 

 spots. Observation of a large number of sorting aprons in operation 

 has shown that it is impossible to obtain good results with a speed 

 exceeding 25 feet per minute. 



(c) In the divided-apron system the tomatoes are dumped upon a 

 conveyor very similar in construction to the simple apron, but usually 

 somewhat wider. Over this conveyor a guide is suspended which 

 divides the stream of tomatoes into two parts, one on each edge, 

 and leaves also a vacant space through the center of the apron. The 

 sorters stand beside the apron, pick out the good tomatoes, and toss 

 them over into the middle section of the apron. All the tomatoes not 

 thrown over into the middle section pass into the waste at the end 

 of the machine. The good tomatoes pass on into washing or rinsing 

 systems. A modification of this system is to remove the bad or 

 spotted stock to the middle section from which they pass into the 

 waste. 



Each tomato, theoretically, is subjected to a scrutinizing inspec- 

 tion, but actually, when the sorters are inspecting rapidly, they will 

 pick up some of the tomatoes and toss them into the center without 

 taking the trouble to turn them over to see the underside. The fact 

 that by this system all the tomatoes, both good and bad, must be 

 actually handled contributes materially to the inefficiency of the sys- 

 tem, as about 75 per cent of the entire stock are sound. It necessarily 

 follows that, as a rule, a larger corps of sorters will be needed than in 

 the simple apron system, where only tomatoes with decayed parts 

 have to be handled. 



In constructing a sorting apron of either type the manufacturer's 

 first problem is to plan one that will meet his requirements as to 

 capacity. A number of tests made on the area a bushel of tomatoes 

 will cover when laid out in a layer one tomato deep showed that, in 

 general, the larger the tomatoes were the smaller was the area cov- 

 ered. The tests made showed a variation of from approximately 7 to 



