) 



REMOVAL OF SPEAY RESIDUE FEOM APPLES AXD PEARS Q 



CLOTH WIPER 



The fruit Vv T as carried forward on a roller conveyor which imparted 

 a turning motion to the fruit as it passed under the rapidly moving 

 cloth disks or flappers. 



OSCILLATING-BRUSH CLEANER 



The fruit was borne on a perforated-belt conveyor on which the 

 individual fruits were kept from contact with each other. The oscil- 

 lating motion of the long brushes on each side of the conveyor rapidly 

 passed the fruit back and forth between them as it moved along and 

 thus brought the surface of the fruit in contact with these brushes as 

 well as with a similar brush overhead. 



COMBINATION OF BRUSH CLEANER AND CLOTH WIPER 



The fruit was first conveyed through a revolving-brush cleaner of 

 the type described above. It was then carried forward on long roll- 

 ers, spirally wound with rope, while cloth flappers were rotated 

 rapidly above the fruit in contact with it and in a direction across its 

 path. 



LIMITATIONS OF DRY-CLEANING METHODS 



These observations and experiments have led to the following con- 

 clusions and suggestions with respect to the dry cleaning of apples 

 and pears. 



As a general conclusion it may be said that the methods of dry 

 cleaning in commercial use, under the best conditions, can not con- 

 sistently remove from apples more than about 30 per cent of the 

 original quantity of spray residue on the fruit when the residue 

 analysis on uncleaned fruit showed not more than 0.04 of a grain of 

 arsenic trioxide per pound. 



The average efficiency obtained for all varieties of apples with the 

 four typical dry-cleaning methods under observation ranged from 15 

 to 35 per cent. This fact indicates that dry cleaning, as a rule, will 

 not be satisfactory for apples having an original residue content above 

 0.015 of a grain per pound, even when there are no complicating 

 factors involved in the cleaning. 



With smooth-skinned pears, a slightly higher efficiency can gen- 

 erally be obtained. From a handling standpoint, however, dry clean- 

 ing is generally much less desirable than washing methods for pears. 

 This statement is also true to a lesser degree for the more tender- 

 skinned apples, such as the T^inter Banana. Some types of dry- 

 cleaning equipment are entirely unsuited for cleaning pears. In gen- 

 eral, any method which subjects fruit to much rolling or moving 

 \ about, so that it comes in frequent sudden contact with parts of the 

 ' equipment or with other fruit is likely to cause mechanical injury. 

 The use of roller conveyors with certain varieties of pears is also 

 attended with danger. Brush cleaners have an element of danger in 

 the possibility that the bristles may puncture the surface of the fruit 

 and allow decay to start. 



There was not much difference inherently between the cleaning 

 efficiency obtained with the better dry cleaners. Variations in effi- 

 ciency were almost invariably due to differences in the mode of oper- 

 ation of the equipment. 



