Patents by Inventor Chih Ming Hwa

Chih Ming Hwa has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Method for inhibition of oxygen corrosion in aqueous systems by the use of a tannin activated oxygen scavenger
    Patent number: 5830383
    Abstract: A method of treating an aqueous system is described which comprises incorporating in the system a hydroxylamine derivative of the general formula: ##STR1## wherein each of R.sub.1, R.sub.2 and R.sub.3 which may be the same or different represents hydrogen, alkyl of 1 to 8 carbon atoms or aryl or a water soluble salt thereof or a precursor thereof, and a tannin in a weight ratio of at least 2:1. This is particularly useful for boiler water systems.
    Type: Grant
    Filed: April 19, 1995
    Date of Patent: November 3, 1998
    Assignee: BetzDearborn Inc.
    Inventors: Brian Greaves, Stephen Clifford Poole, Chih Ming Hwa, Joseph Chwei-Jer Fan
  • Composition and method of inhibiting corrosion
    Patent number: 4101441
    Abstract: The invention disclosed provides a new composition and method for inhibiting corrosion. The present composition is relatively non-toxic, contains no chromates, and consists essentially of an azole, water-soluble phosphate and water-soluble organophosphonic acid. Effective amounts of the corrosion inhibiting composition are used to provide corrosion protection in both ferrous and non-ferrous metals.
    Type: Grant
    Filed: July 21, 1976
    Date of Patent: July 18, 1978
    Assignee: Chemed Corporation
    Inventors: Chih Ming Hwa, Jose T. Jacob
  • Corrosion inhibition
    Patent number: 4066398
    Abstract: Corrosion inhibiting compositions containing hydroxyamine phosphate ester or water-soluble derivative thereof, together with water-soluble zinc salt and 1,2,3-triazole or water-soluble derivative thereof; and methods for inhibiting corrosion in aqueous systems therewith.
    Type: Grant
    Filed: November 12, 1974
    Date of Patent: January 3, 1978
    Assignee: Chemed Corporation
    Inventor: Chih Ming Hwa
  • Method of inhibiting scale
    Patent number: 4048066
    Abstract: The invention disclosed relates to a method for using a new improved composition for inhibiting or preventing accumulation of scale or the like on heating surfaces in an aqueous system. The present composition includes (A) copolymers of styrene sulfonic acid with acrylic or methacrylic acid, and their water-soluble salts; or (B) mixture of polystyrene sulfonic acid with polyacrylic or polymethacrylic acid, and their water-soluble salts.
    Type: Grant
    Filed: November 17, 1976
    Date of Patent: September 13, 1977
    Assignee: Chemed Corporation
    Inventors: Dionisio Guerrero Cuisia, Chih Ming Hwa
  • Method and composition of inhibiting scale
    Patent number: 3959167
    Abstract: The invention disclosed relates to a method for using a new improved composition for inhibiting or preventing accumulation of scale or the like on heating surfaces in an aqueous system. The present composition includes an acrylic polymer, a water-soluble chelant, and an organophosphonic acid and/or their water-soluble salts. In a preferred embodiment, the composition is composed of sodium polymethylacrylate, nitrilotriacetic acid and hydroxyethylidene diphosphonic acid as its water-soluble salts.
    Type: Grant
    Filed: December 10, 1973
    Date of Patent: May 25, 1976
    Assignee: Chemed Corporation
    Inventors: Chih Ming Hwa, Dionisio Guerrero Cuisia, Murrell Leon Salutsky