The Dow Chemical Company

Dow Global Technolgoies LLC

Stewart P Wood

Martin A Langhorst

Thomas L Staples

John W Lyons

William A Heeschen

Warren L Treptow

Sergio S Cutie

Charles F Broomall

Elizabeth E Benedetto

The present invention is directed to a method of locating leaks in a substrate () having a first and a second surface wherein the substrate () is adapted for preventing the flow of a fluid, or components contained in the fluid, through the substrate () from the first surface to the second surface, and a system () useful in the method, wherein the method comprises: a) isolating the first surface from the second surface; b) creating a pressure differential between the first surface and the second surface wherein the pressure on the first surface is higher than the pressure on the second surface; c) contacting the second surface or the exit () of the device () containing the substrate () with a baffle (), wherein the baffle () has a plurality of interconnected parts which form a pattern and the baffle () is of a sufficient size to cover the second surface of the substrate () or the fluid exit point () of the device the substrate () is disposed in and the parts of the baffle () create openings that particles () can pass through; d) exposing the surface of the baffle () to light from a source of diffuse light (); e) contacting the first side of the substrate () with a carrying fluid containing particles () of a particle size that the substrate () is a designed to retain in the first surface of the substrate (); f) monitoring the space above the surface of the baffles () for the light scattered by particles () that have passed through the substrate ().

Filter and membrane defect detection system

A system for analyzing the pore size of a substrate or device containing substrates adapted to separate fluids and has at least two surfaces, a first and a second surface, which are isolated from, one another and wherein the substrate or devices containing the substrates have an exit for fluids passing through the substrate, comprising: a) a particle generator () capable of generating particles of a controlled size; b) a system () for creating a pressure differential between the first and the second surface of the substrate; c) a light source () spaced front the exit of the substrate or device containing the substrate adapted for illuminating particles exiting the exit of the substrate or device containing the substrate; d) a closed flow path from the particle generator to the first surface of the substrate; e) a substrate or device holder () adapted for holding the substrate or device in the proper location in the system; and f) one or more reference images. Also described are methods of utilizing the system to identify pore sizes of substrates.

System and method for analyzing pore sizes of substrates

Absorbent polymer having reduced dusting tendencies

An apparatus and method are disclosed which allow the size of a particle suspended in a medium to be determined virtually independent of the materials'refractive index. The apparatus includes a light source, a sample holder, a detector and a spatial filter. The method of the invention comprises passing the medium containing the particle through a beam of collimated light so that the light which contacts the particle will be scattered; deterring the light which was scattered by the particles from being detected, detecting the light which was not scattered by the particle; and determining the size of the particle from the decrease in the light intensity incident on the detector.

Apparatus and method for using light scattering to determine the size of

A column holder for on-column photometric detection capillary liquid chromatography incorporating a body and a pair of straight edges attached to the body. The straight edges can be conveniently made from a razor blade. The body has two passageways through it that are transverse and intersecting. The first passageway is dimensioned so that a capillary column can be slipped into it or removed from it by hand. The other passageway is for the passage of a light beam from a liquid chromatography photometric detector. The straight edges are slightly separated to form an optical slit in front of the capillary column and are securely clamped to the body of the column holder. A capillary column can be removed from the column holder and be replaced with another capillary column without damaging it and without the necessity of repositioning the slit.

Column holder for on-column photometric detection

Growing community of inventors

Midland, MI, United States of America

Stewart P Wood