Accession Number : AD0427821


Title :   THE TORSION-EFFUSION APPARATUS FOR THE MEASUREMENT OF VAPOR PRESSURE,


Corporate Author : ROCK ISLAND ARSENAL ILL


Personal Author(s) : Martin,Peter ,Jr


Report Date : 26 Nov 1963


Pagination or Media Count : 19


Abstract : The Balson Torsion-Effusion method is based on the measurement of the recoil force developed by effusion gas. The apparatus consists of an effusion vessel suspended by a fiber in such a way that two escaping gas streams tend to twist the fiber in the same direction. The torque produced is then measured by observing the mirror image deflection on a scale. Using this measured angle of deflection, dimensions of the holes, their distances from the axis of the suspension and the torsional rigidity of the fiber, one can caluculate the vapor pressure. The advantages of the method are: (1) it gives an absolute measure of the vapor pressure, (2) only a small amount of substance is required, (3) knowledge of the molecular weight of the material is unnecessary in order to calculate the vapor pressure. A static vacuum system was designed and constructed to be used with the Torsion-Effusion apparatus. It consisted of a mechanical fore pump, 3-stage mercury diffusion pump, liquid nitrogen traps and a cold cathode ionization gage. The applications of the vapor pressure measurements are also discussed. (Author)


Descriptors :   *VAPOR PRESSURE , *TEST EQUIPMENT , MEASUREMENT , GAS DISCHARGES , ORGANIC COMPOUNDS , TORQUE , CHECKOUT PROCEDURES , TEST METHODS


Distribution Statement : APPROVED FOR PUBLIC RELEASE