CANE SUGAR. 



with the main steam pipe ; when the vessel is filled and the cock on the 

 funnel b is closed, the cock c is opened and the pressure of the steam forces 

 the scums through the pipe d, communicating with the press ; the emptying 

 of the montjus is indicated by the escape of steam through the pipe e. 

 Montjus are usually worked in pairs so that their action is nearly continuous. 

 Instead of montjus, pumps are preferable ; those in common use are duplex 

 pumps, which by a simple arrangement are automatic, stopping when the 



FIG. 154. 



pressure in the press which they are filling reaches a certain limit ; a small 

 pipe coming from the air vessel of the pump communicates whatever pressure 

 there is in the air vessel to an arrangement which controls the steam valve ; 

 when the pressure reaches a limit which can be regulated, the steam valve is 

 closed, and the pump stops working. When communication with the filled 

 press is cut off, and the pump connected on to the next press to be filled the 

 pressure is relieved, and the pump automatically starts working. Several 

 patented forms involving the control of the steam valve by the pressure 

 in the air chamber are on the market ; those the writer has encountered 

 have been of German make and are sometimes referred to as ' German 

 pumps.' 



278 



