45 



Later experiments showed how the plates on the dasher 

 also tended to reduce the formation of foam and the appar- 

 atus was changed as 

 shown in Fig. 36. 



Just below the out- 

 let (a) a plate (j) 

 similar to those be- 

 low, is fixed on the 

 dasher, and the out- 

 let is given the shape 

 of a horizontal slit 

 (5 inches long and -J 

 inch wide), placed 

 just above the top of 

 the heating surface. 



Outside the outlet 



is soldered a jug- Fig. 36. 



shaped spout (b), so that the upper edge is just level with the 

 cover of the apparatus. As the milk inside must always rise 

 to the same height as in the spout, the outlet is always covered 

 by a layer of milk (see dotted lines), which prevents the foam 

 from escaping. 



Finally a plate (i) is fixed on the dasher immediately under 

 the cover, and between these two plates the foam gathers and 

 is submitted to the centrifugal force. The foam which is not 

 destroyed, makes its escape through six holes in the center of 

 the upper plate to the spout (d). The result is foam-free milk 

 comes from b, while air and now and then a little foam' comes 

 through d. 



The relative weight of foam-free and foaming milk is given 

 as follows: Foan>free 100, milk from separator 71 to 72, from 

 the milk pump 62 to 65, from the improved pasteurizing heater 

 94 to 97. The speed of the dashers is 280 to 300 revolutions. 



The above is taken from the report in Maelkentidende of 

 an address by P. V. T. Petersen, Sept. 1, 1899. 



One of the last up-to-date Danish heaters constructed ac- 

 cording to the principles just described is shown in Fig. 37 



