Krishna M Gupta

US Patent:

6684685, Feb 3, 2004

Filed:

Jun 21, 2002

Appl. No.:

10/177434

Inventors:

Krishna M. Gupta - Ithaca NY
Akshaya Jena - Ithaca NY

Assignee:

Porous Materials, Inc. - Ithaca NY

International Classification:

G01N 1508

US Classification:

73 38

Abstract:

A porosimeter evaluates the porosity characteristics (specifically, pore volume, pore distribution and liquid permeability) of a porous sample of material. The porosimeter includes a fluid reservoir located below the sample, and a penetrometer comprising a vessel which catches any fluid displaced from the reservoir of fluid, wherein a level of fluid rises in the penetrometer when additional fluid enters the penetrometer. The sample is preferably wetted, with the same type of fluid which is in the reservoir, prior to placing the sample on the porosimeter. The porosimeter preferably also includes a membrane located between the sample and the reservoir of fluid. The membrane has pores with a size smaller than any of the sample pores. Pore volume of the sample is determined by measuring the change in fluid level in the penetrometer after pressure, which is above the bubble point pressure of the sample but below the bubble point pressure of the membrane, is applied to the sample. Permeability is measured by measuring rate of flow while the liquid level is above the sample.

US Patent:

6766257, Jul 20, 2004

Filed:

Jan 8, 2002

Appl. No.:

10/041189

Inventors:

Krishna M. Gupta - Ithaca NY
Nalina Gupta - Ithaca NY
Akshaya Jena - Ithaca NY

Assignee:

Porous Materials, Inc. - Ithaca NY

International Classification:

G01N 3100

US Classification:

702 27

Abstract:

A method of determining the pore structure of the individual layers in a multi-layered composite porous material includes the steps of providing a sample of a multi-layered porous material, sealing the sample in suitable test chamber, filling the pores of the sample material with a wetting liquid, such that the liquid/sample surface free energy is less than the gas/sample surface free energy, using a non-reacting gas to apply pressure to one side of the sample sealed in the test chamber, increasing the gas pressure gradually, so as to displace the liquid from the pores, and increase gas flow through the sample, measuring the pressure at which liquid flows from each successive layer of the sample material, and calculating the pore structure using an equation selected from the group consisting of p=(dS/dV), D=4/p, and f=-d[100(F /F )]/d D.

US Patent:

6789410, Sep 14, 2004

Filed:

Aug 28, 2003

Appl. No.:

10/651074

Inventors:

Krishna M. Gupta - Ithaca NY 14850
Valeriu Smiricinschi - Ithaca NY 14850

International Classification:

G01N 1508

US Classification:

73 38

Abstract:

A porosimeter includes a pressurizable sample chamber with a membrane located directly below the sample. The membrane pores have a smaller size than any of the sample pores of interest. A fluid reservoir is located below the membrane such that the reservoir and the membrane form a seal. In operation, as fluid enters the fluid reservoir through the membrane or a reservoir inlet, fluid already in the fluid reservoir is displaced through a reservoir exit. An inlet in a fluid displacement reservoir receives the fluid displaced from the fluid reservoir. A recirculation line receives fluid from the exit of the fluid displacement reservoir and circulates the fluid into the inlet of the fluid reservoir. In a preferred embodiment, a pump recirculates the fluid through the recirculation line. Fluid returned to the reservoir circulates over the bottom of the membrane, and sweeps air bubbles out of the reservoir.

US Patent:

6845651, Jan 25, 2005

Filed:

Apr 21, 2003

Appl. No.:

10/419501

Inventors:

Krishna M. Gupta - Ithaca NY, US
Akshaya Jena - Ithaca NY, US
Ronald V. Webber - Dryden NY, US
Chandrashekar Venkataraman - Richmond VA, US

Assignee:

Porous Materials, Inc. - Ithaca NY

International Classification:

G01N 1508

US Classification:

73 38

Abstract:

A pressurizable sample chamber of known volume holds a sample with unknown porosity characteristics. The sample chamber has a known pressure (or vacuum). A flow controller preferably controls the flow of the pure gas to be adsorbed by the sample in the sample chamber. A pressure monitor preferably monitors the pressure in the sample chamber. Once the pressure approaches a target pressure, the flow controller is closed. The pressure monitor continues to monitor the pressure until it stops changing when an equilibrium is attained. The amount of gas introduced into the system through the flow controller and the volume and final pressure of the sample chamber are used to calculate the amount of gas adsorbed. This calculation is subsequently used to determine the porosity characteristics of the sample. Some of these characteristics include, but are not limited to, pore distribution and surface area.

US Patent:

7040141, May 9, 2006

Filed:

Apr 21, 2003

Appl. No.:

10/419393

Inventors:

Krishna M. Gupta - Ithaca NY, US
Akshaya Jena - Ithaca NY, US

Assignee:

Porous Materials, Inc. - Ithaca NY

International Classification:

G01N 15/08

US Classification:

73 38

Abstract:

A sample having a plurality of pores is located within a pressurizable chamber. The sample divides the chamber into a first volume and a second volume. A known amount of vapor is introduced into the first volume and the second volume at the same pressure (P). After equilibrium is reached, pressure and decrease in volume of vapor are measured. Pore diameter and pore volume are calculated. A pressure differential is created between the two volumes, and the pressure change is monitored after the pressure differential is introduced. In a preferred embodiment, the pressure is increased in the first volume by a small percentage (ΔP), and the pressure change on both sides of the sample is monitored after the pressure increase. The flow rate of the vapor is calculated using the pressure change. These steps are preferably repeated.

US Patent:

7210335, May 1, 2007

Filed:

Apr 15, 2005

Appl. No.:

11/105705

Inventors:

Krishna M. Gupta - Ithaca NY, US
Akshaya Jena - Ithaca NY, US
William Wilson - Anniston AL, US

Assignee:

Porous Materials, Inc. - Ithaca NY

International Classification:

G01N 15/08

US Classification:

73 38

Abstract:

A sample chamber includes a movable upper chamber. The movable upper chamber includes a center bore opening to a bottom of the chamber, at least one port for introduction of gas under pressure to the center bore, and a first annular seal around the center bore. A stationary lower seat opposing the upper chamber has a center bore aligned with the upper chamber, and includes an exhaust and a second annular seal around the center bore. A test material is placed between the upper chamber and the lower seat. An actuator moves the upper chamber. When the upper chamber is moved down with the first annular seal in contact with an upper surface of a sample of the material and the second annular seal in contact with a lower surface of the sample, gas introduced to the upper chamber goes through the upper chamber and out through the exhaust.

US Patent:

7614279, Nov 10, 2009

Filed:

Oct 10, 2006

Appl. No.:

11/548067

Inventors:

Krishna M. Gupta - Ithaca NY, US
Akshaya Jena - Ithaca NY, US

Assignee:

Porous Materials, Inc. - Ithaca NY

International Classification:

G01N 15/08
B01D 39/00

US Classification:

73 38, 210 85, 210 87, 210 90

Abstract:

A method for determining pore structure characteristics of a filtration cartridge includes the steps of placing a porometry test location isolating device in sealing contact with the filtration cartridge at a desired test location, increasing the porometer test gas pressure until the test gas flows through the cartridge at the test location, measuring the flow rate of the test gas through the test location as a function of differential pressure, reducing the test gas pressure to atmospheric pressure, wetting the test location with a wetting liquid, increasing the test gas pressure again until the test gas flows through the cartridge at the test location, measuring differential gas pressure and gas flow rates through the test location, and converting the measured gas flow rates and differential pressures into through pore throat diameters, largest through pore throat diameter, mean flow through pore throat diameter, pore distribution, and gas permeability of the cartridge.

US Patent:

7882726, Feb 8, 2011

Filed:

Dec 11, 2007

Appl. No.:

11/954035

Inventors:

Krishna M. Gupta - Ithaca NY, US
Akshaya Jena - Ithaca NY, US

Assignee:

Porous Materials, Inc. - Ithaca NY

International Classification:

G01N 15/08

US Classification:

73 38

Abstract:

A method for determining pore structure characteristics of hydrophobic porous materials includes placing a test sample of material in the sample chamber of a porosimetry apparatus, creating a partial vacuum and evacuating the sample chamber to remove air, creating a partial vacuum and evacuating the penetrometer and storage vessel above the water level, releasing the vacuum in a controlled manner, so pressure is applied and water in the penetrometer enters the sample chamber and intrudes into pores of the sample, applying a measured amount of intrusion pressure and measuring the change in volume of water in the penetrometer, and determining pore structure characteristics of the sample based on the change in volume of water in the penetrometer. The method further includes an optional step of applying a desired amount of compressive stress on the sample prior to testing. Nonporous plates optionally are used to measure x-y plane pore structure.