_|_________|_______|_______|_______|_______|_______|_______|
| t| 397.4 | 447.4 | 497.4 | 547.4 | 597.4 | 647.4 | 697.4 |
| 240 v| 1.92 | 2.09| 2.26| 2.42| 2.57| 2.71| 2.85|
| h| 1200.9 |1234.3 |1261.9 |1287.6 |1312.8 |1337.6 |1362.3 |
|________|_________|_______|_______|_______|_______|_______|_______|
| t| 399.3 | 449.3 | 499.3 | 549.3 | 599.3 | 649.3 | 699.3 |
| 245 v| 1.89 | 2.05| 2.22| 2.37| 2.52| 2.66| 2.80|
| h| 1201.2 |1234.8 |1262.5 |1288.2 |1313.3 |1338.2 |1362.9 |
|________|_________|_______|_______|_______|_______|_______|_______|
| t| 401.0 | 451.0 | 501.0 | 551.0 | 601.0 | 651.0 | 701.0 |
| 250 v| 1.85 | 2.02| 2.17| 2.33| 2.47| 2.61| 2.75|
| h| 1201.5 |1235.4 |1263.0 |1288.8 |1313.9 |1338.8 |1363.5 |
|________|_________|_______|_______|_______|_______|_______|_______|
| t| 402.8 | 452.8 | 502.8 | 552.8 | 602.8 | 652.8 | 702.8 |
| 255 v| 1.81 | 1.98| 2.14| 2.28| 2.43| 2.56| 2.70|
| h| 1201.8 |1235.9 |1263.6 |1289.3 |1314.5 |1339.3 |1364.1 |
|________|_________|_______|_______|_______|_______|_______|_______|
t = Temperature, degrees Fahrenheit.
v = Specific volume, in cubic feet, per pound.
h = Total heat from water at 32 degrees, B. t. u.
[Graph: Temperature of Steam--Degrees Fahr.
against Temperature in Calorimeter--Degrees Fahr.
Fig. 15. Graphic Method of Determining Moisture Contained in Steam from
Calorimeter Readings]
MOISTURE IN STEAM
The presence of moisture in steam causes a loss, not only in the
practical waste of the heat utilized to raise this moisture from the
temperature of the feed water to the temperature of the steam, but also
through the increased initial condensation in an engine cylinder and
through friction and other actions in a steam turbine. The presence of
such moisture also interferes with proper cylinder lubrication, causes a
knocking in the engine and a water hammer in the steam pipes. In steam
turbines it will cause erosion of the blades.
The percentage by weight of steam in a mixture of steam and water is
called the _quality of the steam_.
The apparatus used to determine the moisture content of steam is called
a calorimeter though since it may not measure the heat in the steam, the
name is not descriptive of the function of the apparatus. The first form
used was the "barrel calorimeter", but the liability of error was so
great
|