GRAINER PROCESS 59 



immersed in long shallow wooden or iron vats. These vats 

 rest on a strong wooden frame. They are from ioo to 150 

 feet long usually 12 feet wide and from 20 to 24 inches 

 deep ; provided with 4 to 6 steam pipes having a diameter 

 of 4 to 5 inches and hung on pendants 4 to 6 inches above 

 the bottom of the vats. These pipes are within a few feet 

 of the same length as the grainer, and so arranged that the 

 salt can be conveniently removed towards the outer side of 

 the grainer. Over the top of the grainer is a strong plat- 

 form to receive the salt taken from it for proper drainage ; 

 this also supports the pendants holding the steam pipes in 

 their position. In most of the grainer blocks the salt is re- 

 moved from the grainers by attendants called "lifters." In 

 others an ingenious device called a " raker " does this 

 work, automatically moving the salt constantly from the 

 front end of the grainer to the back where it drops into 

 properly constructed " conveyors " which deposit it in the 

 salt bins. Where no rakers are employed the salt is re- 

 moved every 24 hours. The brine which is "settled" in 

 exactly the same manner as that treated by the kettle and 

 pan methods is allowed to run into the grainers at the front 

 end in the same proportion as the water evaporates from 

 the brine. The only attention required, when the salt is not 

 "lifted" is to pay proper attention to the supply of brine 

 and the regulation of the steam which is all attended by one 

 man. In most work soft coal is used as a fuel under the 

 boilers, that and the expense for the fireman being a consider- 

 able item in the grainer plant. To obtain the best effect in 

 a grainer system, the temperature of the heated brine should 

 be kept at or near the boiling point when no lifting or 

 removal of salt is in progress. To do this we must first 

 supply to the grainers an abundance of high pressure steam, 

 and secondly the constant supply of brine required for the 

 grainers while evaporation is going on must enter at a tem- 

 perature but little lower than that of the brine in the grainer. 

 For this purpose two large tanks, so-called settlers, are em- 



