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FIG. 66.-Steam at 95 Pounds Pressure Containing 1.88 per cent. Water.

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FIG. 68.-Steam at 95 Pounds Pressure, Throttled to 53 Pounds, Superheating 9 Degrees.-No Water in Cond

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FIG. 69.-Steam at 55 Pounds.-Boiler Priming Violently.

continued. The jet returned to steady action and normal appearance within a few seconds after the feed pump was stopped, notwithstanding that the boiler was almost completely full of water. EXPERIMENT 4.-The boiler being steadily making steam 8° superheated and supplying the same to an engine through about 100 feet of 21-inch pipe, newly felted with one inch thickness of hair felt, a jet of steam was made to blow through a petcock about two feet above the throttle valve on the steam chest of the engine. Fig. 70 shows the appearance of the steam when the engine was running with a total steam consumption of about 600 pounds of steam per hour.

Fig. 71 shows the same jet when the engine stopped and no

steam was passing through the steam pipe. Jet 70 was so laden with water that it flowed with irregular gusts, resembling those occurring when the boiler was priming (Fig. 69), but of less violent character. And yet the boiler was making slightly superheated

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FIG. 70.-Dry Steam after Traversing 100 Feet of Covered Pipe at Velocity } of 50 Feet Per Second.

steam, as proven both by the thermometer at C (Fig. 59) and the transparent appearance of the jets from the apparatus at the boiler. The explanation of this paradox is as follows: The steam pipe to the engine runs beneath the engine foundation from the boiler to a point below the vertical pipe, B (Fig. 70); thence it rises in B, and finally runs vertically downward to the engine in A.

When the engine is stopped, the water condensed by the pipe remains at the bottom of B, and the jet contains only a gray mist, as per Fig. 71. When the engine is running, the water of condensation is swept along with the steam with sufficient power to cause

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FIG. 71.-Dry Steam after Traversing 100 Feet of Covered Pipe at Velocity of 5 Feet Per Second.

it to be carried up B, and show the wetness of Fig. 70. A valve placed at the lower end of B to drain the water out of the pipe will prevent the wet appearance of the jet in Fig. 70 when a feeble current is passing through A and B, but such drainage fails sensibly to alter the appearance in Fig. 70, when the velocity through the pipe is 50 feet per second.

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