y6 Condensed Milk and Milk Powder 



nants of condensed milk, the parts should be scalded, dried and re- 

 placed in the machine. In order to guard against all possible con- 

 tamfnation by remnants of wash water, it is advisable to reject the 

 first few cans of milk of the next filling. When not in use, the 

 filling machine should be covered with clean cloth, or oil cloth, to 

 protect it from dust and flies, etc. 



As soon as the cans are filled, they should be "capped." If 

 allowed to stand open, dust, dirt and flies, or other insects are prone 

 to reach their interior, and the prolonged exposure of the condensed 

 milk to. the air causes the surface to crust over. 



I SEALING 



Kinds of Seals. — The seal must be air-tight and firm enough to 

 prevent its breaking during the rough treatment to which the cans 

 are exposed in transportation. There are several methods of seal- 

 ing the cans, depending largely on the construction of the can. Most 

 of the cans used are sealed with solder. There is a groove around 

 the opening, the cap fits into this groove and the latter is filled with 

 solder. In the case of cans which are sealed without solder, the cap 

 or the entire end of the can is crimped onto the can so> as to make a 

 hermetical seal. The McDonald seal with the friction cap, the Gebee 

 seal with the burr cap, and the Sanitary can seal with the top of the 

 can crimped on after filling, are the chief types of solderless seals. In 

 the case of the McDonald seal, a tightly fitting cap with a wide 

 flange is pressed into the opening. The "capped" can passes under 

 a series of steel rollers pressing the flange firmly against the top of 

 the can. This seal is very simple, but is not very strong and not 

 hermetically tight. In the case of the Gebee seal, a rim projects 

 around the opening of the can. After the cap is inserted, it is 

 crimped over this rim by means of a series of revolving dies. This 

 seal is reasonably strong but not hermetically tight. The Sanitary 

 can is entirely open at one end when filled. The cover or end is 

 crimped around the periphery of the body of the can by means of 

 revolving dies. This seal is reasonably strong and usually hermet- 

 ically tight. 



The chief advantages of the seals without solder lie in the sav- 

 ing of labor, and the reduction of the cost due to the omission of 

 solder. The principal reason for which they are not used more gen- 



