CHAi^GES IN FRESH BEEF DUEING COLD STORAGE. 3 



down to about 32° F. before filling, though when filled with warm 

 beef it may run up to 50° F. 



The main cooler is simply a second cooler into which the par- 

 tially chilled beef from the fore cooler is run to be thoroughly 

 chilled and held for shipment. In some of the large meat-packing 

 establisliments, which have several beef coolers, warm beef is run 

 into one cooler on one day, into another cooler on the second day, 

 and so on, the chilled beef being removed from the first cooler in 

 time for its refilling Txatli warm beef. This practice accomplishes 

 the same result as the use of a fore cooler. 



SYSTEMS OF REFRIGEKATION. 



In commercial meat-packing establishments in this country the 

 ammonia-compression system of refrigeration is used almost entireh\ 

 There are, however, a number of methods by which the refrigeration 

 is distributed for the purpose of chilling the coolers. The more 

 important of these are : (1) Closed brine-coil system ; (2) sheet-brine 

 system; (3) brine-spray system. In each case the refrigerating agent 

 is sodium chlorid or calcium chlorid brine that has been chilled by 

 the direct expansion of liquid ammonia in closed coils. 



Closed-coU system. — Refrigerated brine is pumped through closed 

 coils located in bunkers directly above the coolers. The bunkers are 

 so constructed as to provide for gravity circulation of air, the cold 

 aic falling from one side of the bunker into the cooler below and 

 the warm air from the cooler rising at the other side to be refrig- 

 erated as it passes over the brine coils. This system also accom- 

 plishes a partial drying of the air as it passes over the cold brine 

 coils, which condense a part of the moisture and the dissolved im- 

 purities that the air contains. The closed-coil system is the one most 

 commonly used for the refrigeration of fresh-meat coolers. 



Sheet-hn7)£ system. — This system is similar in principle to the 

 closed-coil system. Instead of passing through closed coils, how- 

 ever, the refrigerated brine is allowed to trickle over a series of sus- 

 pended muslin curtains located in a bunker room similar to that used 

 in the closed-coil system. 



Brine-spray systerro. — In this system the refrigerated brine is 

 sprayed from a series of pipes located in a bunker room similar to 

 that which is used in the two other systems. One advantage of this 

 system over the other just mentioned is that less head room is required 

 in tlx' l)iird<er rr)om. 



When i)ropeily installed any one of these systems is considered 

 to give satisfactory results. It is A^ery important, however, that a 

 systnn of rcfrigcfiition for fritsli-riicat coolois shoidd ])i"()vi(le for 

 afjiindant lefrigeration and for a thorough and faiily rapid circula- 

 tion of fiir-. 



