THE EQUIFEX DISINPECTOR 367 



either oval or circular in section, surrounded by a jacket, 

 and closed at either end by a door. Steam is admitted 

 through safety-valves to the jacket and to the central 

 chamber, in which the objects to be disinfected are placed. 

 The pressure usually employed is about 20 lb. in the 

 interior of the cylinder and about 25 lb. in the jacket, the 

 object being to slightly superheat the steam and diminish 

 the extent to which condensation takes place on the objects 

 to be disinfected. The present method of eliminating the 

 air is to apply a vacuum apparatus, whereby the air within 

 the disinfecting chamber is rarefied to 15 to 20 inches of 

 mercury — i.e., one half to two-thirds of the air is extracted 

 before steam is admitted. In some, cases a current of 

 warm air is also admitted before disinfection, so as to 

 diminish the extent of condensation. The drying of objects 

 after disinfection is effected by extracting some part of the 

 vapour by means of the vacuum, and allowing the re- 

 mainder to evaporate under the influence of the heat from 

 the jacketed walls of the chamber. 



The Equifex Disinfector. — The Equifex disinfector for 

 absolute disinfection is cylindrical and has no jacket. 

 Steam is admitted to coils at the bottom, and in some 

 cases also at the top of the disinfecting cylinder at a 

 pressure of about 50 lb., and serves to communicate to the 

 steam so much heat as is lost by radiation through the sides 

 and doors. Air is eliminated by allowing the steam on first 

 admission to blow off through an outlet pipe carrying a 

 thermometer, which should register 95° C. before disinfec- 

 tion proper begins. In this way the air from the stove is 

 got rid off; and by intermitting pressure for five minutes 

 the air in the pores of the objects is likewise driven out on 

 the sudden expansion of the volume of vapour condensed 

 in them. The working pressure of steam is 10 lb. per 

 square inch ; and, the steam being saturated, its pressure, 



