314 CITY MILK SUPPLY 



plate. Water and ice are put inside the cone and stirred frequently 

 with an agitator to keep the cold water against the cone or cold water 

 is circulated through the cone through an inlet pipe at the bottom and 

 an outlet pipe at the top. From a reservoir on top of the cone milk is 

 discharged through perforated holes onto the cold outer surface of the 

 cone and is cooled as it runs down in a thin sheet into a trough at the 

 bottom whence it drains into a receiving can. Except in the hotter 

 dairy sections and those where neither cold water nor ice are generally 

 available this simple machine has proved a very useful one. 



The Star type of cooler also is much used by small dairymen, particu- 

 larly for cooling cream. It is made of two sheets of heavily tinned copper 

 bent into corrugations and so soldered together at the ends that a space 

 is left between the sheets for water to circulate. Thus the cooler has 

 a fluted surface over which the milk flows in a thin film. Water is intro- 

 duced to the cooler at the bottom and passes out at the top while the milk 

 runs from a tank into a perforated distributing trough at the top of cooler 

 and down over the cold surface of the cooler into a trough and out through 

 a spout into a receiving can. This is a good cooler but a frail one, for it 

 is made of such thin metal to insure a rapid exchange of heat between the 

 warm milk and the cold water that it is easily injured by rough handling 

 in washing it, or by dropping it on the floor or by forcing water through 

 it under too great head. 



In another type of cooler the milk flows from a tank into a perforated 

 distributing trough and over heavily tinned corrugated copper cylinders 

 that are set horizontally in cast-iron supporting racks and vertical water 

 columns from which they may be removed for cleaning. The cylinders 

 are cooled by circulating water or brine through them or by circulating 

 brine through the lower cylinders and water through the upper >v ones. 

 The water or brine is introduced at the bottom of the water column at 

 one side of the cooler, runs through the bottom cylinder up through the 

 water column at the other side, up it and back through the next cylinder 

 to the first water column, up it into the third cylinder, and so on till it 

 passes out of the cooler at the top of the first water column. The cylin- 

 ders are corrugated to slacken the flow of milk over them and are repre- 

 sented to be very strong. The great advantage of this type of coolers 

 is that they are easily taken apart for cleaning. 



Coolers of the continuous-surface type are so built that an unbroken 

 surface on both sides is presented for the milk. Horizontal, round or 

 triangular tubes are united by tinned brass strips carefully soldered to 

 the tubes, making the cooler section a rigid unit. The advantages 

 claimed for the triangular tubes are that they offer a maximum of cooling 

 surface in a little space and that they retard the downward flow of milk 

 over the cooling board. Water or brine is circulated from bottom to 

 top of the board through the system of tubes and the milk is cooled as it 



