Methods of and apparatus for determining propagation characteristics of thermic waves in gases

• Main Author: HENRY MARTIAL EMILE DU BOSCQ DE BEAUMO
• Format: Patent
• Language: English
• Published: 30.10.1968
• Subjects: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIRCHEMICAL OR PHYSICAL PROPERTIES; MEASURING; MEASURING QUANTITY OF HEAT; MEASURING TEMPERATURE; PHYSICS; TESTING; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR

1,132,249. Measuring temperature electrically; measuring intensity of laser beams. SOC. POUR L'UTILISATION RATIONNELLE DES FLUIDES. April 4, 1966 [April 2, 19651, No. 14970/66. Headings G1A and G1N. [Also in Division H1] The temperature of emission of a thermic wave is deduced from measuring the propagation velocity of the wave front as it travels, by conduction, through a gaseous medium of known pressure and initial temperature. As shown in Fig. 1, a pulse generator 18 triggers a spark discharge device 17 to discharge a capacitor bank 16 through a cylindrical coil 3 and at the same time, the time base sweep of a C. R. O. 23 is started. The arrival of the thermic wave at the axis of the cylinder is detected by a platinum resistance wire 5 in an A. C. bridge circuit 21, the output of which is connected to the Y plates of the C. R. O to give a trace, Fig. 2 (not shown), from which the propagation velocity may be determined. In an alternative embodiment, Figs. 3, 4 and 5 (not shown), for measuring the intensity of the output of a laser, the laser output, which may be reduced in cross-section by lenses (37, 38) passes axially through a cylindrical detector coil (5'). Instead of a C. R. O., a square wave may be generated of duration equal to the time between emission and detection of the thermic wave, and the leading and trailing edges of this square wave may respectively start and stop an electronic clock.