AUTOMATIC WATER LEVEL FOR ARNOLD 

 STERILIZERS 



IVAN C. HALL 



Department of Pathology and Bacteriology., University of California, Berkeley 



Experienced technicians, and untrained students, alike err occa- 

 sionally in allowing Arnold sterilizers to burn dry, involving rapid 

 depreciation of the apparatus and inconvenience incidental to 

 the necessity of repairs. 



The following arrangement has been in operation for some time 

 in our laboratory where over one hundred and seventy-five dif- 

 ferent persons use the gi'oup of twelve connected sterilizers with 

 absolutely no required attention on their part to the water 

 supply. 



The water main is connected to the flush tank of a water closet, 

 placed on the bench at the end of the battery of sterilizers. The 

 inlet valve is operated by the rise and fall of the usual brass globe, 

 so that a constant level is maintained. In case any defect should 

 cause the valve to fail to close, an overflow is arranged to carry 

 the surplus water to the sewer, thus avoiding the possibility of a 

 flooded room. This contingency has not yet arisen. The ster- 

 ilizers which stand upon gas plates are connected with the supply 

 tank and with one another by means of siphons made of f inch 

 lead pipe bent into U tubes. These are started by filling with water 

 and holding the ends closed with the fingers until one end can he 

 released under the water in the tank. Proceeding thus from the 

 tank to the first sterilizer, and from this to the second, the suc- 

 cessful operation of the connecting siphons was established to 

 start with one at a time. 



The water, of course, soon reaches a common level in all, as 

 determined by the setting of the float valve. Any operation 

 of the sterilizers draws upon the supply tank through the siphons 

 for water sufficient to maintain the common level, and the lowering 

 of the float operates the valve automatically to replenish the 

 supply as needed. 



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