REMOVAL OF SPEAY RESIDUE FROM APPLES ASTD PEAES y 



TANK DIPPING IN BOXES 



Many variations of the tank type of apparatus existed, some involv- 

 ing the use of electric power for conveying the boxes of fruit. In one 

 under experimental observation the fruit was immersed in the clean- 

 ing solution while in the boxes. The latter were pushed forward by 

 hand, lifted from the cleaning solution for a short draining period. 

 and then immersed in the rinsing tank, to which fresh water was 

 supplied through overhead diffused sprays. The period of exposure 

 to cleaning solution varied from three to five minutes. The boxes 

 were then stacked for drying. 



DEEP SUBMERSION 



The apples or pears were given a submersion treatment to the 

 depth of about 5 feet by means of several conveyors, which very 

 gently carried the fruit up and down in the cleaning solution. The 

 rinsing was done by similar means, and the drying was accom- 

 plished either by means of a cloth draper towel with pendent cloth • 

 attached or by rotating brushes. The period of exposure to the 

 cleaning solution was about five minutes. 



ALKALINE-SOLUTION WASHER 



The essential cleaning feature of the most commonly used washer 

 of the alkaline-solution type was a bath of warm solution which 

 floated the fruit while it was subjected to o/erhead diffused sprays 

 of warm solution. The rinsing was accomplished by sprays of 

 fresh water. There was no drying arrangement, but under com- 

 mercial operation the fruit was immediately subjected to a paraffin 

 and oil coating treatment. 



INFLUENCE OF TEMPERATURE ON EFFECTIVENESS OF SOLUTION 



By raising the temperature of the acid solution increased clean- 

 ing efficiency was obtained in washing apples from which the residue 

 could not be otherwise satisfactorily removed. It can not be said, 

 however, that all such lots were cleaned by this means to meet the 

 world tolerance. In some cases it seemed that orJy a modification of 

 the spraying practices would make the fruit capable of being washed 

 satisfactorily, because even the best washing method has certain 

 limitations. 



The temperature of the solution should be at least 80° to 85 c F. 

 and preferably 90° to 100° if consistent cleaning is to be obtained. 

 With such temperatures it was found that the acid concentration 

 could be materially reduced below the quantity that was required 

 when the solution was cold, without sacrificing cleaning efficiency. 

 In many cases 1 or 2 gallons of acid to 100 gallons of water were 

 sufficient if the solution was warm. In several cases the saving in 

 acid consumption more than paid for the warming of the solution 

 by steam coils or by electric heaters. These sources of heat can 

 be obtained commercially and adapted to almost every washing 

 machine that is now manufactured. 



The higher temperature in the solution seems to increase to a 

 certain degree the chemical reaction between the lead arsenate and 

 the hydrochloric acid and to bring about a softening or melting of the 

 19095°— 29 2 



