662 



OLEOMAKGAKINE. 



separately inspected and thrown into another 

 tank containing pure water, where it remains 

 about the same time as at first. Pieces rich 

 in oil are the only ones thrown into this tank ; 

 all the others are cut off and put into tierces, 

 to be rendered into tallow. The fat in the sec- 

 ond tank is again inspected and passed into a 

 third, after which third washing it is a perfectly 

 pure white fat. The next step is to elevate 

 this fat, in cars holding about 600 pounds each, 

 to -the top of the building or third floor, along- 

 side the disintegrating machines. These are 

 like the regular meat-hasher. This machine 

 consists of a series of sharp blades set on an 

 axis like the thread of a screw. A closely-fit- 

 ting chamber or cylinder placed horizontally 

 contains these blades. The cylinder is divided 

 into two portions, hinged together on one side, 



and capable of being securely fastened on the 

 other when the machine is in operation. When 

 necessary to clean the machine, the upper half 

 can easily be thrown back. The fat is dumped 

 on a large trough supported above the cylinder. 

 This trough or feeder has an aperture in one 

 corner, which fits over a hole in the upper part 

 of the cylinder through which the fat is fed to 

 the machine. It is introduced piece by piece, 

 and the revolving knives cut it very fine ; after 

 which it is forced out through a fine sieve at 

 the opposite end, and falls into kettles, ready 

 for the next process. The comminuted fat is 

 now in a state which enables it to be rendered 

 at a very low temperature. This rendering is 

 accomplished in a series of caldrons, jacketed 

 and surrounded by water, as is seen in the ac- 

 companying illustration. 



The water in the jacket is heated to the boil- 



ing-point by the introduction of live steam, 

 which in turn heats the caldron containing the 

 fat, causing it to melt at a temperature of from 

 1 14 to 122 F. Much care is taken to prevent 

 getting above 122, since the lower the tempera- 

 ture is kept, the better is the product obtained. 

 During this rendering process about 5 per cent 

 of ordinary salt is added, which helps the mem- 

 brane to settle. Each caldron or kettle holds 

 about 2,300 pounds of fat, which is the usual 

 product of an hour's work of the hashing 

 machine. As soon as the fat falls into the 

 kettle, the steam is turned on to heat the 

 water in the jacket, after which the heat thus 

 accumulated is found sufficient to finish the 

 process. When the fat is completely rendered, 

 cold water is poured into the jacket. Some- 

 thing over two hours is occupied from the time 

 the hasher begins before 

 the fat is allowed to rest. 

 Kevolving agitators keep 

 the mass in constant mo- 

 tion during the rendering 

 process, thus equalizing 

 the temperature and fa- 

 cilitating the rendering. 

 When the fat finally comes 

 to a rest, a membrane (or 

 "scrap") settles to the 

 bottom of the kettle, and 

 the pure fat is left on the 

 top. Usually the separa- 

 tion is complete and satis- 

 factory; but in case the 

 fat has become water - 

 soaked in the washing 

 process, it is necessary 

 to agitate the whole mass 

 rapidly several times, after 

 which the membrane will 

 sink to the bottom. The 

 rendered fat is left at rest 

 about half an hour, when 

 the pure fat is ready to be 

 drawn off and strained in- 

 to the "settling-kettles." 

 An emulsion of water and 

 oil in the condition of froth floats on the surface 

 of the rendered fat, which is ladled off. The ren- 

 dered fat remains in the settling-kettles from 

 one to three hours, and is kept at a tempera- 

 ture of 118 to 122 F., the water in the jacket 

 being kept at about 135. When the settling 

 is complete, and the refined fat is at the proper 

 temperature, it is drawn off through a fine 

 sieve into tanks or cars, which are immediately 

 removed to the "seeding-room," which is kept 

 at a temperature of 85. In this room the fat 

 begins to solidify very slowly, the more solid 

 constituents crystallizing out at first, the whole 

 mass at last assuming a kind of mushy consist- 

 ency. The "seeding" or crystallizing process 

 requires from thirty-six to forty-eight hours, 

 and must not be hurried. When the rendered 

 fat is in the proper condition, it is pressed so as 

 to separate the butter-oil from the stearine. 



