US5264250A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Antimicrobial hydrophilic coating
Assignee: RTX Corp
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Filing: 1992-08-05
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Granted: 1993-11-23
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Expires: 2012-08-05
Abstract
Abstract Heat transfer surfaces in condensing heat exchangers are often coated with a hydrophilic coating to provide wetting and wicking. This coating is typically porous and continuously moist during operation and, therefore, a potential breeding ground for microbes. The inclusion of an antimicrobial agent, such as silver oxide, in the coating inhibits microbial growth and improves adhesion to the heat transfer surfaces.
Inventors
- 👤 John W. Steele
- 👤 Philip J. Birbara
- 👤 Robert W. Marsh
- 👤 Timothy D. Scull
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 22:47
CPC Classifications
C; C09; C09D; C09D5/00; C09D5/14; F; F28; F28D; F28D17/00; F28D17/005; F28F; F28F13/00; F28F13/18; F28F13/182; F28F2245/00; F28F2245/02; F28F2265/00; F28F2265/20
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
156 words
A method for coating heat transfer surfaces of a condensing heat exchanger with an antimicrobial hydrophilic coating, comprising the steps of: a. flowing the coating in the form of a slurry through said condensing heat exchanger, wherein said slurry intimately contacts and coats said heat transfer surfaces; and b. heating said coated heat transfer surfaces to dry and cure said slurry thereby forming a coating on said heat transfer surfaces, wherein said slurry is comprised of: a. an adhesive agent; b. an insolubilizer; c. an inorganic compound wherein said inorganic compound is selected from the group consisting of silica, calcium silicate, and mixtures thereof; d. from about 0.1 wt. % to about 1.0 wt. %, based upon the total weight of the slurry, of silver oxide; and e. a solvent; whereby said adhesive agent, said insolubilizer, said inorganic compound, and said silver oxide are dispersed in said solvent thereby forming a slurry which is essentially homogeneous.
Claim 2
Independent Claim
156 words
A method for coating heat transfer surfaces of a condensing heat exchanger with an antimicrobial hydrophilic coating, comprising the steps of: a. flowing the coating in the form of a slurry through said condensing heat exchanger, wherein said slurry intimately contacts and coats said heat transfer surfaces; and b. heating said coated heat transfer surfaces to dry and cure said slurry thereby forming a coating on said heat transfer surfaces, wherein said slurry is comprised of: a. an adhesive agent; b. an insolubilizer; c. an inorganic compound wherein said inorganic compound is selected from the group consisting of silica, calcium silicate, and mixtures thereof; d. from about 0.1 wt. % to about 1.0 wt. %, based upon the total weight of the slurry, of silver oxide; and e. a solvent; whereby said adhesive agent, said insolubilizer, said inorganic compound, and said silver oxide are dispersed in said solvent thereby forming a slurry which is essentially homogeneous.
Claim 3
Dependent Claim
148 words
A method for coating heat transfer surfaces as in claim 1 further comprising the steps of sequentially heating said coated heat transfer surfaces, wherein said sequential heating is comprised of heating said heat transfer surfaces to a range of about 175° F. to about 185° F. for between about 0.25 hrs and 1.0 hrs, to a range of about 195° F. to about 205° F. for between about 0.5 hrs and about 1.5 hrs, to a range of about 215° F. to about 225° F. for between about 0.25 hrs and about 1.0 hrs, to a range of about 245° F. to about 255° F. for between about 0.25 hrs and about 1.0 hrs, to a range of about 295° F. to about 305° F. for between about 0.5 hrs and about 1.5 hrs, and to about 500° F. for between about 1.5 hrs and about 2.5 hrs.
Claim 4
Dependent Claim
35 words
A method for coating heat transfer surfaces as in claim 1 wherein said slurry intimately contacts said heat transfer surfaces for about 10 minutes to about 20 minutes before said heat transfer surfaces are heated.
Claim 5
Dependent Claim
16 words
A method for coating heat transfer surfaces as in claim 1, wherein said solvent is water.
Claim 6
Dependent Claim
29 words
A method for coating heat transfer surfaces as in claim 1, wherein said adhesive agent is selected from the group consisting of potassium silicate, borosilicate glass, and mixtures thereof.
Claim 7
Dependent Claim
33 words
A method for coating heat transfer surfaces as in claim 1, wherein said insolubilizer is selected from the group consisting of zinc oxide, and silicofluorides of sodium, potassium, barium, manganese, and mixtures thereof.
Claim 8
Dependent Claim
72 words
A method for coating heat transfer surfaces as in claim 4, wherein said slurry contains between about 20.0 wt % and about 30.0 wt % of said adhesive agent, between about 10.0 wt % and about 20.0 wt % of said insolubilizer, between about 10.0 wt % and about 20.0 wt % of said inorganic compound, between about 0.3 wt % and about 0.7 wt % of said silver oxide, balance water.
Claim 9
Dependent Claim
69 words
A method for coating heat transfer surfaces as in claim 4, wherein said slurry contains about 25 wt % to about 26 wt % of said adhesive agent, about 12.5 wt % to about 13.5 wt % of said insolubilizer, about 14.0 wt % to about 15.0 wt % of said inorganic compound, and about 0.45 wt % to about 0.55 wt % of said silver oxide, balance water.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-11-22 | 1997-05-24 | 1997-11-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-11-22 | 2001-05-24 | 2001-11-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-11-22 | 2005-05-24 | 2005-11-23 | $7700.00 | Window Closed / Lapsed |