Speed control for screw-power testing machines driven by direct current motors
- Publisher
- Elsevier Science
- Year
- 1937
- Tongue
- English
- Weight
- 108 KB
- Volume
- 223
- Category
- Article
- ISSN
- 0016-0032
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✦ Synopsis
A calorimetric determination has been made by Drs. N. S. Osborne, H. F. Stimson, and D. C. Ginnings, of the thermal properties of saturated water, in both the liquid and gaseous states, from Ioo ° C. (56 kg./cm?) to the close vicinity of the critical point, 374 ° C. (225 kg./cm?). This new determination supplements a previous determination in the same laboratory in the range from o to 27o ° C. With the new apparatus designed and built to withstand severe conditions of temperature and pressure, satisfactory measurements were possible up to within one degree of the critical point.
Special tests of the possibility of mixture of the liquid and vapor phases in evaporation experiments indicated freedom from this effect, except within one degree of the critical point. These tests included direct measurements of specific volume at 37 o° C., which confirmed the calorimetric results.
A compilation was made of the thermal properties of . saturated water in the interval from ~oo to 374 ° C., giving the vapor pressure and the specific volume, entropy, and enthalpy or heat content for both the liquid and gaseous states. This compilation is based on the results of the present measurements, supplemented by data covering the range from Ioo to 27 °0 C. from the previous investigation. These latter data are in accord with those of the present investigation at the same temperatures. In RP983 (Journal of Research for April) in which this work is reported, a number of comparisons between these values and certain groups of similar data from other laboratories are shown graphically.
SPEED CONTROL FOR SCREW-POWER TESTING MACHINES
DRIVEN BY DIRECT CURRENT MOTORS.