43 



pipe. Although this regulator worked fairly well, it did not 

 remain long in use and the following system gained on it. 



T. C. Nielsen (Denmark) with his tipping regulator Fig. 33, 

 proposed to solve this problem in another way by simply 

 diverting the milk not hot enough back to the milk tank. This 

 is done by letting the hot milk run into a cup AA with spouts 

 on opposite sides. The cup rests on a frame d e, which is 

 balanced on a three-cornered steel so that it may tip easily 

 one way or the other to conductor f or 1. The balance is reg- 

 ulated by two moveable metal balls g & h, so that a very small 

 weight will tip the cup. To do this there is inserted a tube 

 ab filled with mercury to the bottom of the bulb, b. In a there 

 is also a drop of alcohol which is expanded by increased 

 heat and thus forces the mercury from a to b, anfl this is 

 enough to tip the cup AA. As soon as the milk becomes 

 cooler the mercury falls back in a and the cup turns the milk 

 stream into the other conductor. By using alcohol of various 

 boiling points the temperature at which it acts may be varied. 



The milk which is not warm enough may be made to pass 

 a cylinder and act on a ball cock and thus either open the 

 steam valve or partly close off the cold milk from the heater, 

 but the main point is that the milk passing as pasteurized 

 really has been heated to the desired degree. 



These regulators were introduced in 1895-1896, but in 

 1899 Mr. P. V. F. Petersen, in a lecture, declared that they 

 had not been adopted in the practical dairy work, although 

 he does not seem to condemn them altogether. There can be 

 no doubt that there is a crying need for some such device not 

 only for pasteurizing but also for regulating the heating of 

 milk for separating. 



DANISH GOVERNMENT EXPERIMENTS WITH HEAT- 

 ERS. 



When the Danish government proposed to make it com- 

 pulsory for creameries to pasteurize all cream and milk bar- 

 ring that used for cheese making, the Experiment Station 

 from 1897 to 1899 again took up the problem of pasteurizing 

 heaters with special reference to their capacity and economy 

 in using steam. 



The first improvement w r as made by soldering on the out- 

 side of the heating drum a series of rings (Fig. 34) at a down- 



