CENTRAL SCIENTIFIC CO., CHICAGO, U. S. A. 



383 



Nos. 9830-1 (Patented). 



DeKhotinsky Bimetallic Thermo- 



Regulator. 

 (Patent applied for.) 



OVENS, DRYING, ELECTRICALLY HEATED AND REGULATED 



OVENS, Drying, Triple Wall, DeKhotinsky, Electrically Heated and Regulated (Patented), with 

 new bimetallic regulator and new system of ventilation providing for greatest possible uni- 

 formity of temperature throughout the oven chamber. 



Construction: These ovens are constructed of asbestos board on a steel frame, with three 

 walls. The space between the outer v.-alls is packed with magnesia-asbestos (magnesia 85 

 per cent.; asbestos 15 per cent.) Between the inner walls is an air space through which 

 the air passes upward from the heating units in the base. Ports are provided in the side 

 walls of this air space, permitting the entrance of the heated air to the oven chamber, in 

 which it passes up and out through an opening in the false top. The location of these 

 ports has been carefully and scientifically determined so as to provide a continuous current of 

 heated air to every corner of the inner chamber, making the temperature uniform through- 

 out. This feature (patent pending) is peculiar to the DeKhotinsky Triple Wall Oven, and 

 insures a uniformity not possible in electrically heated ovens of any other type. The outer 

 door is double walled and packed with magnesia-asbestos. It is beveled on the edges, mak- 

 ing close contact, when closed, with the walls, thus preventing leakage of heat. An inner 

 glass door is provided for inspection of the interior without cooling the contents. Between it 

 and the outer door is a dead air space for insulation purposes. 



Heating of the oven is effected by means of four of our standard heating units of chromel 

 wire wound on lavite. These heating units are located in the base of the oven between the 

 two bottoms with an iron deflector placed over them to prevent radiation of heat from the 

 units into the inner chamber. Three of these heating units are connected in parallel to the 

 switch contact springs, and may be added to the circuit one at a time as desired. The fourth 

 is connected in circuit with the contact points of the thermo-regulator. These heating units 

 can be easily and quickly replaced from outside the oven without the necessity of opening 

 the door or stopping the operation. 



Temperature control of the oven is secured by means of our new bimetallic thermo-regulator 

 which is made from invar-brass ribbon, and can be set at any desired temperature from that 

 of the surrounding air up to the maximum heat capacity of the oven. This range of tem- 

 perature permits the use of these instruments as ovens, parafflne baths, or sterilizers. The 

 precision of action of this thermo-regulator is 14 C. The make-and-break contact of the 

 thermo-regtflator is located outside the oven to prevent the possibility of ignition of inflam- 

 mable gases developed in the inner chamber, which often occurs when the contact is made 

 and broken inside. A pilot lamp on top of the oven is connected in series with the thermo- 

 regulator, enabling the operator to determine at a glance whether the oven is regulating. 

 These instruments can be operated on either A.C. or D.C. circuits. 



No A B C 



Height inside, inches 10% 14% 19% 



Width inside, inches 7 12 17 



Depth inside, inches 6% 11% 14 



Shelf space, square inches 91 282 476 



9830. For 110 volts $55.00 90.00 145.00 



9831. Por 220 volts 57.50 92.50 147.50 



