﻿REFRIGERATION OF DRESSED POULTRY IN TRANSIT. 



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and thorough mixing of the salt, which produces very low tempera- 

 tures. These four, together with the simple box arrangement 

 shown in figure 12, are the types of ice bunkers now in common use. 

 Most of the others are minor modifications of these five. 



The various types of cars studied show that there is a wider diver- 

 gence in the construction of the ice bunkers than in any other single 

 refrigerator-car essential. This is undoubtedly due to a recognition 

 on the part of the car builder of the importance of this fitting in the 

 performance of the car, and the varying forms of the bunker repre- 

 sent the endeavors of 

 the builders to meet 

 modern requirements 

 in the transporta- 

 tion of refrigerated 

 freight. The ice bunker in a refriger- 

 ated car holds a place analogous to that 

 of the refrigerating machinery in a 

 stationary plant. It must chill every 

 inch of working space in the compart- 

 ment depending upon it. It would 

 seem, from the observations made on 

 the types of cars described, that the aim 

 of the builder must be to induce a circu- 

 lation of air which will convey the lower 

 temperatures at the bunker ends to the 

 center of the car. To do this efficiently 

 the bunker must be assisted by proper 

 insulation on the surfaces of the car. 

 Correlating the construction of the 

 bunkers with the table 

 of efficiencies of the 

 four types of cars, two 

 essential principles for 

 the production of low 

 temperatures stand out prominently. First, the bunker must per- 

 mit of the ice being finely crushed and evenly mixed with the salt; 

 and, second, there must be a free admittance of the warm air of 

 the car at the top of the bunker and a free exit of the cold air at 

 the bottom. Such requirements are apparently met most suc- 

 cessfully by the tank on the one hand and the wire basket on the 

 other. In this case simplicity of construction has been compatible 

 with efficiency. 



Various attempts have been made to use overhead ice bunkers 

 and, in a few instances, brine pipes for circulation have been tried, 

 but in most cases the objectionable features were so numerous that 



Fig. 8. — Siphon bunker used in type A car 



