Quantachrome Corporation

Other

Seymour Lowell

Nicholas N Novella

David W Sumell

Martin A Thomas

Stuart S Warszycki

For use in a sorption analysis system, a method compensating for measuring error due to the time-dependent evaporation of liquid coolant and the resulting change in the level of the coolant and temperature increase around the stem of the sample cell, during a gas sorption analysis of a sample in the sample cell. This error compensation does not inhibit coolant evaporation and is without recourse to mechanical means or other physical contrivances for causing the system to act as if the coolant were not evaporating. This method employs fixed and time-dependent data, including: changing coolant level and sample cell stem temperature changes, both of which can be obtained off-line, cold zone volume changes, and volumes of adsorptive gas transferred into the sample cell, to generate progressive error correction; whereby, system output is being corrected throughout the duration of the sorption analysis.

Method for compensating for the time-dependent change in coolant level during gas sorption analysis

A high pressure mercury porosimeter for continuous pore volume distribution measurements that simultaneously receives two or more test sample penetrometers, each containing a powder or porous solid sample to be tested. Two or more individual tests can be simultaneously performed per high pressure cycle in a single porosimeter. Only one access port is required to access 2 or more penetrometers greatly increasing sampling throughput, reducing multiple test time requirements without significant equipment cost increase.

Apparatus for determining pore volume distribution of multiple samples

An adsorption and desorption analyzer for performing analyses on samples comprises a manifold for selectively storing one or two gases or vapors having different critical temperatures, at least two cells constructed and arranged to store a sample for analysis, a supply line having an isolation valve connecting each cell to the manifold, an absolute pressure transducer for monitoring the pressure in the manifold, vacuum means, a microprocessor for controlling the operation of the isolation valves and the application of gas or vapor or vacuum to the manifold and a coupling line having a differential pressure transducer having a smaller range than the range of the absolute pressure transducer, enables an operator to determine data points for characteristics of the samples under study more precisely and more rapidly than is possible using an analyzer having an identical absolute pressure transducer for each cell to determine the characteristics of the samples stored in the cells. The analyzer is also constructed and arranged to determine the characteristics of additional samples in addition to the first pair of samples compared.

Method and apparatus for performing adsorption and desorption analysis

A sorption analyzer for performing surface measurement analysis on sample material. The sorption analyzer calibrates the instrument and the sample cell using the adsorbate gas.

Method for measuring a sample sorption and a sample cell void volume and

An automatic adsorption and desorption analyzer for independently performing analyses on a plurality of powder samples includes a manifold connected through a plurality of independently operated valves to a corresponding plurality of sample cells. A pressure transducer measures the manifold pressure and a plurality of pressure transducers are respectively coupled to the sample cells to independently measure the pressure at each of the sample cells. The system measures the volume of gas adsorbed (desorbed) by each of the samples that is required to establish specified equilibrium pressures at the sample cells, thereby to provide pressure-volume points which can be used to prepare adsorption (or desorption) isotherms, BET curves, and other information concerning the properties of the samples.

Automatic volumetric sorption analyzer

As understood, the effectiveness of using mercury penetration or intrusion into a powder sample to measure the pore volume distribution thereof is based on negative capillarity, i.e. that a porous solid will repulse a non-wetting liquid, such as mercury, except as the mercury is forced into the pores thereof by pressure. Whereas in the prior art the mercury is intruded into the powder sample at pressures in an ascending order, but with gaps therebetween and thus according to a 'discontinuous' pressure pattern, the within inventive method practices the mercury intrusion technique according to an ascending pressure pattern that is 'continuous'. The pore volume distribution curve produced by the within inventive method is thus more accurate than that of prior art data-gathering methods, since it is produced without interpolation between curve-plotting data points.

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Lake Worth, FL, United States of America

Seymour Lowell