Bulletin . 8 FLOW OF HEAT THROUGH FURNACE WALLS. useless, because the bricks containing the holes might have beenmore porous than others, or some of the holes might have openedinto cracks; the holes could not well be inspected. Therefore, theworth of the readings lies as much in their rates of change as in theiractual values at any time. The sets of thermocouples in the side wall are designated a, b, andd, and the sets in the roof are designated c and e. The couplesin each set are numbered from 1 to 4. The reading of any thermo-couple is referred to by the letter of the set, with the number of
Bulletin . 8 FLOW OF HEAT THROUGH FURNACE WALLS. useless, because the bricks containing the holes might have beenmore porous than others, or some of the holes might have openedinto cracks; the holes could not well be inspected. Therefore, theworth of the readings lies as much in their rates of change as in theiractual values at any time. The sets of thermocouples in the side wall are designated a, b, andd, and the sets in the roof are designated c and e. The couplesin each set are numbered from 1 to 4. The reading of any thermo-couple is referred to by the letter of the set, with the number of thecouple as subscript. The temperature readings of the thermocouples embedded in thewall and roof were taken on a number of tests. INSIDE Fire brick. i \H?*i|r ?%<* OUTSIDE Figure 3.—Construction of furnace walls and position of OF TEMPERATURE CURVES. The readings of test No. 16 are platted in figures 5, 7, and 9. Tinstest is a fair representative of other tests in which complete sets ofwall and arch readings were obtained every 20 or 30 minutes throughthe entire test of 29 hours duration. The test was run until thewall temperatures reached equilibrium, thai is, until they ceasedto increase. The readings were platted on time as abscissas, so thatthe slopes of the curves show the rate of change. Figure 5 shows the temperature readings for the entire test of thethermocouple sets placed at b and c. (See fig. 1.) This chart shows DISCUSSION OF TEMPERATUKE CURVES. 9 that, excepting perhaps within 1 or 2 inches from the inside of thefurnace, the brickwork is nearly cold when the test is started, andthat as the heat flows out through the wall from the inner surfacethe temperatures of the portions of the w
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