Daniel L Comstock

US Patent:

7491334, Feb 17, 2009

Filed:

Jul 20, 2005

Appl. No.:

11/185104

Inventors:

Daniel L. Comstock - San Diego CA, US

Assignee:

North Pacific Research, LLC - San Marcos CA

International Classification:

B01D 61/02
B01D 61/12
B01D 63/10
B01D 63/12

US Classification:

210652, 210650, 210651, 210653, 21032169, 210501

Abstract:

The present invention provides a method of treating a reverse osmosis membrane for boron rejection enhancement, comprising contacting the reverse osmosis membrane with a chemical coating such as PHMB, wherein the reverse osmosis membrane is part of a single-pass reverse osmosis system is configured to reduce the boron concentration of normal seawater or brackish water to less than a predetermined amount.

US Patent:

51981165, Mar 30, 1993

Filed:

Feb 10, 1992

Appl. No.:

7/832941

Inventors:

Daniel L. Comstock - Escondido CA
Lee A. Durham - Oceanside CA

Assignee:

D.W. Walker & Associates - San Marcos CA

International Classification:

B01D 6510

US Classification:

210636

Abstract:

The optimum antifoulant concentration and cleaning interval for reverse osmosis membranes is determined by providing samples of a liquid to be purified in a reverse osmosis system, the samples having a range of antifoulant concentrations added. The zeta potential for each sample is measured, and the amount of antifoulant that provides the lowest (most negative) zeta potential is selected as the preferred antifoulant concentration. A cleaning frequency sample of the liquid to be purified with the preferred antifoulant concentration is prepared and passed across a cleaning frequency membrane that passes dissolved matter in the permeate but does not pass colloidal material. The rate of change in flow of the permeate of the cleaning frequency sample is measured as a function of time, and the cleaning frequency of the cleaning frequency sample is determined. In one embodiment, the cleaning frequency membrane used in the testing is comparable to the filter support used in the reverse osmosis system, but has no separation membrane thereon. A test cell for measuring permeation through the cleaning frequency membrane is provided.

US Patent:

61800562, Jan 30, 2001

Filed:

Dec 10, 1998

Appl. No.:

9/208473

Inventors:

Thomas E. McNeel - Mem TN
Daniel L. Comstock - Escondido CA
Maryam Z. Anstead - Houston TX
Richard A. Clark - Collierville TN

Assignee:

Buckman Laboratories International Inc. - Memphis TN
Betz Dearborn Inc. - Trevose PA

International Classification:

C23F 1402

US Classification:

422 15

Abstract:

A composition for minimizing biological and/or colloidal fouling is described, which includes an anionic antiscalant and a cationically charged biocide. Further, a method of controlling fouling is described and achieved by introducing a formulation of the present invention into an aqueous system which uses a separation membrane. The compositions used in the present invention are compatible with such separation systems and preferably prevent membrane fouling.

US Patent:

53743571, Dec 20, 1994

Filed:

Mar 19, 1993

Appl. No.:

8/033860

Inventors:

Daniel L. Comstock - Escondido CA
Lee A. Durham - Oceanside CA
Mark A. Warren - Murrietta CA
Bryce P. Anderson - Carlsbad CA

Assignee:

D. W. Walker & Associates - San Marcos CA

International Classification:

C02F 128
C02F 154

US Classification:

210666

Abstract:

Colloidal matter is removed from a fluid flow by first adsorbing a coagulant onto the surface of a finely divided filter media, and thereafter passing a colloid-containing fluid through the filter media. The adsorbing of coagulant is accomplished with the filter off-line, and it is returned on-line for filtering of the fluid. After the coagulant is adsorbed onto the filter media, it is not necessary to continue feeding coagulant during on-line operation, as the adsorbed coagulant captures the colloidal matter in the fluid and retains it on the surface of the filter media. The captured colloidal matter is removed during back washing of the filter media.