Patents by Inventor Chih M. Hwa
Chih M. 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).
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Patent number: 5587109Abstract: 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: GrantFiled: April 19, 1995Date of Patent: December 24, 1996Assignee: W. R. Grace & Co.-Conn.Inventors: Brian Greaves, Stephen C. Poole, Chih M. Hwa, Joseph C. Fan
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Patent number: 5244600Abstract: A method for inhibiting or preventing corrosion of metals in contact with an aqueous system containing dissolved oxygen comprising adding to the system an oxygen scavenger having the formula ##STR1## wherein n is 5 or 6, lactone derivatives thereof, or its water soluble salts, in an amount effective to substantially remove the dissolved oxygen.Type: GrantFiled: March 2, 1992Date of Patent: September 14, 1993Assignee: W. R. Grace & Co.-Conn.Inventors: Dionisio G. Cuisia, Chih M. Hwa, Murrell L. Salutsky
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Patent number: 5183574Abstract: A method of comprising iron in an aqueous system comprising adding to the system a copolymer of styrene sulfonic acid and methacrylic acid or its water soluble salt in an amount effective to disperse the iron contained therein.Type: GrantFiled: November 18, 1991Date of Patent: February 2, 1993Assignee: W. R. Grace & Co.-Conn.Inventors: Chih M. Hwa, John A. Kelly, Wun T. Tai, Lai-Duien G. Fan, Robert P. Kreh, Brian Greaves
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Patent number: 5176849Abstract: A composition and method of inhibiting corrosion in boiler-steam condensate systems comprising adding to the system N,N-dihydrocarbylhydroxylamine and N-hydrocarbylhydroxylamine in amounts effective to inhibit corrosion.Type: GrantFiled: April 15, 1992Date of Patent: January 5, 1993Assignee: W. R. Grace & Co.-Conn.Inventors: Chih M. Hwa, Dionisio G. Cuisia, Ronald L. Oleka
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Patent number: 5167866Abstract: This invention relates to controlling corrosion in aqueous systems and more particularly to using certain calcium insensitive phosphonomethyl amine oxide compounds. The compounds of this invention are water soluble phosphonomethyl amine oxides having at least one oxidized tertiary amine group of the formula: ##STR1## and water soluble salts thereof and having a cloud point of at least about 25 ppm.Type: GrantFiled: December 15, 1989Date of Patent: December 1, 1992Assignee: W. R. Grace & Co. Conn.Inventors: Chih M. Hwa, John A. Kelly, Janet Neton, Patricia M. Scanlon, Roger R. Gaudette
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Patent number: 5096595Abstract: This invention relates to controlling scale formation in aqueous systems and more particularly to using certain calcium insensitive phosphonomethyl amine oxide compounds having at least one oxidized tertiary amine group of the formula: ##STR1## and water soluble salts thereof.Type: GrantFiled: February 11, 1991Date of Patent: March 17, 1992Assignee: W. R. Grace & Co.-Conn.Inventors: Chih M. Hwa, John A. Kelly, Janet Neton, Patricia M. Scanlon, Roger R. Gaudette
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Patent number: 5069798Abstract: This invention relates to certain calcium insensitive phosphonomethyl amine compounds and their use as scale control agents for treating aqueous systems. The compounds of this invention are water-soluble phosphonomethyl amine compounds having the formula: ##STR1## and water soluble salts thereof selected from the group consisting of N-phosphonomethyl iminodiacetic acid, N,N-bis-phosphonomethyl- 2-(hydroxyethoxy)ethylamine, 4-(phosphonomethyl)-2-hydroxy-2-oxo-1,4,2-oxazaphosphorinane, N,N-bis-phosphonomethyl taurine and N,N-bis-phosphonomethyl ethylamine; and having a cloud point of at least about 25 ppm as determined by the CA500 cloud point test or a water soluble salt of said phosphonomethyl amine.Type: GrantFiled: December 15, 1989Date of Patent: December 3, 1991Assignee: W. R. Grace & Co.-Conn.Inventors: Chih M. Hwa, John A. Kelly, Janet Neton, Patricia M. Scanlon, Roger R. Gaudette
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Patent number: 5051532Abstract: This invention relates to novel organic phosphonate compounds which can be used as water treatment agents. More specifically, this invention relates to the compound N,N-bis-phosphonomethyl taurine N-oxide which may be represented by the formula: ##STR1## and its water soluble salts, which can be employed for the control of scale and/or corrosion.Type: GrantFiled: December 15, 1989Date of Patent: September 24, 1991Assignee: W. R. Grace & Co.-Conn.Inventors: Chih M. Hwa, John A. Kelly, Janet Neton, Patricia M. Scanlon, Roger R. Gaudette
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Patent number: 5019343Abstract: This invention relates to a method for preventing corrosion and inhibiting the formation of scale deposition in aqueous systems. More specifically, it relates to using certain calcium insensitive phosphonomethyl amine compounds having the formula: ##STR1## wherein either R.sub.1 is selected from hydrogen, hydrocarbyl, hydroxy-substituted hydrocarbyl, alkoxy-substituted hydrocarbyl; and R.sub.2 is selected from hydrocarbyl, hydroxy-substituted hydrocarbyl, alkoxy-substituted hydrocarbyl, carboxyl-substituted hydrocarbyl, --CH.sub.2 PO.sub.3 H.sub.2, and --C.sub.2 H.sub.4 N(CH.sub.2 PO.sub.3 H.sub.2).sub.2 ; or R.sub.1 and R.sub.2 together form an alicyclic ring having 3 to 5 carbon atoms, optionally along with oxygen atoms, phosphorus atoms or both oxygen and phosphorus atoms in the ring, and water soluble salts thereof.Type: GrantFiled: December 15, 1989Date of Patent: May 28, 1991Assignee: W. R. Grace & Co.-Conn.Inventors: Chih M. Hwa, John A. Kelly, Janet Neton, Patricia M. Scanlon, Roger R. Gaudette
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Patent number: 4980128Abstract: Corrosion of metals in contact with system water in an aqueous system is inhibited by adding to the system water an effective amount of an oxygen scavenger selected from the group of nitrones having the formula: ##STR1## wherein R.sub.1 and R.sub.2 may be the same or different and are each a member selected from the group consisting of hydrogen and hydrocarbon radicals having between 1 and 10 carbon atoms, and R.sub.3 is a hydrocarbon radical having between 1 and 10 carbon atoms; or water soluble salts thereof.Type: GrantFiled: March 16, 1987Date of Patent: December 25, 1990Assignee: W. R. Grace & Co.-Conn.Inventors: Dionisio G. Cuisia, Chih M. Hwa, Murrell L. Salutsky
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Patent number: 4977292Abstract: This invention relates to novel organic phosphonate compounds and more particularly to the compound 4-phosphonomethyl-2-hydroxy-2-oxo-1,4,2-oxazaphosphonrinane N-oxide and water soluble salts thereof. These compounds are useful as water treatment agents which can be employed for the control of scale and/or corrosion control.Type: GrantFiled: December 15, 1989Date of Patent: December 11, 1990Assignee: W. R. Grace & Co.-Conn.Inventors: Chih M. Hwa, John A. Kelly, Mita Adhya
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Patent number: 4973744Abstract: This invention relates to novel organic phosphonate compounds, and more particularly to ethoxylated N,N-bis-phosphonomethyl 2-(hydroxy) ethylamine N-oxides and their water soluble salts. These novel organic phosphonates are useful as water treatment agents which can be employed for the control of scale and/or corrosion.Type: GrantFiled: December 15, 1989Date of Patent: November 27, 1990Assignee: W. R. Grace & Co.-Conn.Inventors: Chih M. Hwa, John A. Kelly, Mita Adhya
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Patent number: 4847001Abstract: A method and composition for inhibiting the corrosion of metal surfaces in contact with the system water of aqueous systems are disclosed, which use a combination of at least one compound selected from 2,5 dihydroxybenzene sulfonic acid and its water soluble salts and at least one amine selected from neutralizing amines and hydroxylamines.Type: GrantFiled: July 1, 1987Date of Patent: July 11, 1989Assignee: W. R. Grace & Co.-Conn.Inventors: Dionisio G. Cuisia, Chih M. Hwa, Murrell L. Salutsky
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Patent number: 4680125Abstract: A composition for inhibiting deposition of scale in aqueous systems is disclosed which comprises carboxymethylcellulose and gluconic acid or glucoheptonic acid or both, or their water soluble salts. The composition is incorporated in the aqueous system in concentrations sufficient to substantially completely prevent scale deposition.Type: GrantFiled: June 6, 1986Date of Patent: July 14, 1987Assignee: W. R. Grace & Co.Inventors: Dionisio G. Cuisia, Chih M. Hwa
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Patent number: 4649025Abstract: Composition for inhibition of ferrous metal corrosion consisting essentially of (a) HEDPA compound and (b) HPAA compound. Optionally the composition may also include (c) an azole.Type: GrantFiled: September 16, 1985Date of Patent: March 10, 1987Assignee: W. R. Grace & Co.Inventors: Chih M. Hwa, Wayne A. Mitchell
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Patent number: 4631131Abstract: The accumulation of scale in an aqueous system is inhibited by the addition of a copolymer of maleic acid or anhydride or fumaric acid and allyl sulfonic acid and a water soluble organic phosphonic acid such as aminotri(methylene phosphonic acid), ethylenediaminetetra(methylene phosphonic acid), hydroxyethylidene diphosphonic acid and 2-phosphonobutane tricarboxylic acid-1,2,4 or water soluble salts thereof. Scale can actually be removed by the addition of these materials to pressurized boiler water systems. Allyl or vinyl copolymers, a phosphonate, and optionally a water soluble, hardness precipitating agent such as a carbonate or a phosphate may be used when treating pressurized boilers to provide an in-service cleaning effect.Type: GrantFiled: September 10, 1985Date of Patent: December 23, 1986Assignee: R. W. Grace & Co.Inventors: Dionisio G. Cuisia, Chih M. Hwa
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Patent number: 4609483Abstract: A composition for inhibiting deposition of scale in aqueous systems is disclosed which comprises carboxymethylcellulose and gluconic acid or glucoheptonic acid or both, or their water soluble salts. The composition is incorporated in the aqueous system in concentrations sufficient to substantially completely prevent scale deposition.Type: GrantFiled: March 7, 1985Date of Patent: September 2, 1986Assignee: W. R. Grace & Co.Inventors: Dionisio G. Cuisia, Chih M. Hwa
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Patent number: 4600524Abstract: The accumulation of scale in an aqueous system is inhibited by the addition of a copolymer of maleic acid or anhydride or fumaric acid and allyl sulfonic acid and a water soluble organic phosphonic acid such as aminotri(methylene phosphonic acid), ethylenediaminetetra(methylene phosphonic acid), hydroxyethylidene diphosphonic acid and 2-phosphonobutane tricarboxylic acid-1,2,4 or water soluble salts thereof. Scale can actually be removed by the addition of these materials to pressurized boiler water systems. Allyl or vinyl copolymers, a phosphonate, and optionally a water soluble, hardness precipitating agent such as a carbonate or a phosphate may be used when treating pressurized boilers to provide an in-service cleaning effect.Type: GrantFiled: December 8, 1983Date of Patent: July 15, 1986Assignee: W. R. Grace & Co.Inventors: Dionisio G. Cuisia, Chih M. Hwa
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Patent number: 4581145Abstract: The accumulation of scale in an aqueous system is inhibited by the addition of a composition comprising a copolymer of maleic acid or anhydride and vinyl sulfonic acid and an organic phosphonate such as aminotri(methylene phosphonic acid), hydroxyethylidene diphosphonic acid, or a water soluble salt thereof.Type: GrantFiled: March 11, 1985Date of Patent: April 8, 1986Assignee: Dearborn Chemical CompanyInventors: Dionisio G. Cuisia, Chih M. Hwa, Anne H. Kemp
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Patent number: 4350606Abstract: Corrosion in steam condensate lines is inhibited by maintaining a mix of a hydroxylamine compound and a neutralizing amine in the water.Type: GrantFiled: October 3, 1980Date of Patent: September 21, 1982Assignee: Dearborn Chemical CompanyInventors: Dionisio G. Cuisia, Chih M. Hwa