INDUSTRIAL, A N D ENGINEERING C H E M I S T R Y
December, 1931
1329
Heater Arrangement and Power Consumption
The electrical space heaters are of the type having a heating value of 350 watts a t 110 volts. Eight space heaters were mounted in one tray by use of cross supports. The eight units were connected in such a way as to provide 700 watts a t 110 volts, or 1400 watts a t 220 volts, and a total consumption of energy of 4500, 9000, 9100, or 18,200 watts. Bus bars are provided for connecting the thirteen trays of space heaters to the power-supply leads. Each bank of space heaters serves as the heat supply for two drying trays, one above and one below. Condenser Design
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The condenser employed is of multiple-tube design with the tubes electrically welded into a rectangular metal housing. The condenser ends are 13 inches wide by 19 inches high, and the side walls are 24 inches long. The shell of the condenser is made of 0.25-inch cold-rolled sheet iron, and the 6-inch
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Figure 2-Front
View
haust port leading to the condenser. This space varied in width from 1.5 to 4 inches with the narrow dimensions a t the four edges of the back of the vacuum chamber. The 6-inch exhaust port is attached to the vacuum chamber by means of a standard 6-inch pipe flange. As the available tray space is 49 inches high, the vacuum chamber proper is approximately 7 cubic feet in volume. With the volume of the space provided back of the trays leading to the 6-inch exhaust port, together with the condenser volume of 3.5 cubic feet, there result approximately 12 cubic feet of total volume to be evacuated. As is shown in the upper right hand corner of Figure 2, the right and left inside walls of the vacuum chamber have narrow shelves, 0.5 by 1.5 by 19 inches (28 on each side), cast into the L
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