US4795871A
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Method and apparatus for heating and drying fabrics in a drying chamber having dryness sensing devices
Assignee: MICRO DRY INCORPORATED TULSA OKLAHOMA A CORP OF NEVADA
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Filing: 1987-09-03
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Granted: 1989-01-03
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Expires: 2007-09-03
Abstract
Abstract The invention relates to a microwave heating and drying method and apparatus utilizing a multiplicity of microwave propagating sources positioned about a heating and drying chamber. The microwave energies are optimized to provide a greater uniformity in the heating and drying of articles disposed in the heating and drying chamber, while preventing interference of the wave propagations. The microwave pulses are cross-polarized and time-multiplexed. Also, the focusing and spread angles are controlled. The end point of the drying cycle is sensed to control microwave generation.
Inventors
- 👤 Robert D. Strattan
- 👤 Mary E. O'Connor
- 👤 James R. Sorem, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 10:12
CPC Classifications
D; D06; D06F; D06F58/00; D06F58/20; D06F58/26; D06F58/266; D06F58/30; F; F26; F26B; F26B25/00; F26B25/22; F26B3/00; F26B3/32; F26B3/34; F26B3/347; H; H05; H05B; H05B6/00; H05B6/64; H05B6/6447; H05B6/645; H05B6/6458; H05B6/6461; H05B6/80; D06F2103/00; D06F2103/02; D06F2103/08; D06F2103/10; D06F2103/28; D06F2103/34; D06F2103/64; D06F2105/00; D06F2105/28; D06F58/32; D06F58/34; D06F58/36; D06F58/38; H05B2206/00; H05B2206/04; H05B2206/046
Claims Analysis
Total Claims: 40
Claim 1
Independent Claim
86 words
A method of sensing the end point of a dry condition in a moist fabric disposed in a microwave heating and drying chamber, comprising the steps of: (a) substantially continuously measuring relative humidity at an outlet of said heating and drying chamber; (b) comparing the relative humidity at said outlet with a relative humidity reading at an inlet of said chamber; and (c) determining said end point of the dry condition when said outlet relative humidity falls to within a given percentage of said inlet reading.
Claim 2
Independent Claim
86 words
A method of sensing the end point of a dry condition in a moist fabric disposed in a microwave heating and drying chamber, comprising the steps of: (a) substantially continuously measuring relative humidity at an outlet of said heating and drying chamber; (b) comparing the relative humidity at said outlet with a relative humidity reading at an inlet of said chamber; and (c) determining said end point of the dry condition when said outlet relative humidity falls to within a given percentage of said inlet reading.
Claim 3
Dependent Claim
12 words
The method of claim 1, wherein said given percentage is approximately 6%.
Claim 4
Dependent Claim
33 words
The method of claim 1, further comprising the step of: (d) controlling a power output of at least one microwave generator disposed about said chamber in response to the comparison of step (b).
Claim 5
Independent Claim
77 words
A method of sensing the end point of a dry condition in moist fabric disposed in a microwave heating and drying chamber, comprising the steps of: (a) substantially continuously measuring absolute humidity output of said chamber; (b) comparing said absolute humidity output with a chosen baseline reading obtained at a start of the heating and drying of said fabric; and (c) determining said end point when said output reaches within a given value of said chosen baseline.
Claim 6
Independent Claim
77 words
A method of sensing the end point of a dry condition in moist fabric disposed in a microwave heating and drying chamber, comprising the steps of: (a) substantially continuously measuring absolute humidity output of said chamber; (b) comparing said absolute humidity output with a chosen baseline reading obtained at a start of the heating and drying of said fabric; and (c) determining said end point when said output reaches within a given value of said chosen baseline.
Claim 7
Dependent Claim
16 words
The method of claim 4, wherein said given value is approximately one millivolt above the baseline.
Claim 8
Dependent Claim
33 words
The method of claim 4, further comprising the step of: (d) controlling a power output of at least one microwave generator disposed about said chamber in response to the comparison of step (b).
Claim 9
Independent Claim
87 words
A method of sensing the end point of a dry condition in moist fabric disposed in a microwave heating and drying chamber, comprising the steps of: (a) substantially continuously measuring anode temperature of at least one magnetron disposed about said chamber during a heating and drying cycle of said moist fabric; (b) sensing a sudden or sharp increase in said anode temperature; and (c) reducing or terminating power to at least said one magnetron in response to said increase of anode temperature in accordance with step (b).
Claim 10
Independent Claim
87 words
A method of sensing the end point of a dry condition in moist fabric disposed in a microwave heating and drying chamber, comprising the steps of: (a) substantially continuously measuring anode temperature of at least one magnetron disposed about said chamber during a heating and drying cycle of said moist fabric; (b) sensing a sudden or sharp increase in said anode temperature; and (c) reducing or terminating power to at least said one magnetron in response to said increase of anode temperature in accordance with step (b).
Claim 11
Dependent Claim
30 words
The method of claim 7, further comprising the step of: (d) controlling a power output of at least two of said magnetrons in response to the increase in anode temperature.
Claim 12
Dependent Claim
79 words
The method of claim 7, further comprising the step of improving the uniformity of heating and drying of an article or articles of moist fabric being heated and dried by microwaves within said heating chamber, by (d) directing of multiple microwaves into said heating and drying chamber in a substantially non-interfering manner from at least two substantially oppositely planar positions disposed about said heating chamber, whereby said article or articles of moist fabric are more uniformly heated and dried.
Claim 13
Dependent Claim
20 words
The method of claim 9, wherein said directed microwaves from said two positions are cross-polarized with respect to each other.
Claim 14
Dependent Claim
32 words
The method of claim 10, wherein said directed microwaves from said at least two positions are generated independently by time-multiplexing, whereby simultaneous heating from said at least two positions does not occur.
Claim 15
Dependent Claim
32 words
The method of claim 9, wherein said directed microwaves from said at least two positions are generated independently by time-multiplexing, whereby simultaneous heating from said at least two positions does not occur.
Claim 16
Dependent Claim
31 words
The method of claim 12, wherein said microwaves are directed at said article or articles from two positions, with an angular focus between said two positions of less than 90 degrees.
Claim 17
Dependent Claim
31 words
The method of claim 10, wherein said microwaves are directed at said article or articles from two positions with an angular focus between said two positions of less than 90 degrees.
Claim 18
Dependent Claim
31 words
The method of claim 9, wherein said microwaves are directed at said article or articles from two positions with an angular focus between said two positions of less than 90 degrees.
Claim 19
Dependent Claim
28 words
The method of claim 9, wherein each microwave position has an angular spread of microwaves of approximately between 30 and 40 degrees as directed into said heating chamber.
Claim 20
Dependent Claim
28 words
The method of claim 10, wherein each microwave position has an angular spread of microwaves of approximately between 30 and 40 degrees as directed into said heating chamber.
Claim 21
Dependent Claim
28 words
The method of claim 12, wherein each microwave position has an angular spread of microwaves of approximately between 30 and 40 degrees as directed into said heating chamber.
Claim 22
Dependent Claim
28 words
The method of claim 13, wherein each microwave position has an angular spread of microwaves of approximately between 30 and 40 degrees as directed into said heating chamber.
Claim 23
Dependent Claim
86 words
An apparatus for substantially uniformly heating and drying an article or articles of moist fabric by microwaves, in accordance with the method of claim 9, comprising: a heating and drying chamber having at least two microwave generating means for generating microwaves from at least two substantially opposite planar positions disposed about said chamber, in a substantially non-interfering manner, said microwaves being directed into said heating chamber from said two positions for the heating and drying of said article or articles of moist fabric with substantial uniformity.
Claim 24
Dependent Claim
22 words
The apparatus of claim 20, wherein there are between two and six generating means for generating microwaves disposed about said heating chamber.
Claim 25
Dependent Claim
31 words
The apparatus of claim 20, wherein the generating means for generating said microwaves are arranged about said heating chamber such that said generated microwaves are cross-polarized with respect to each other.
Claim 26
Dependent Claim
41 words
The apparatus of claim 22, further comprising circuit means operatively connected to said generating means for time multiplexing said generating means, such that each generating means is powered independently whereby simultaneous heating from more than one generating means does not occur.
Claim 27
Dependent Claim
41 words
The apparatus of claim 20, further comprising circuit means operatively connected to said generating means for time multiplexing said generating means, such that each generating means is powered independently whereby simultaneous heating from more than one generating means does not occur.
Claim 28
Dependent Claim
45 words
The apparatus of claim 23, wherein certain ones of said generating means are angularly arranged about said heating chamber such that the microwaves are focused into said heating chamber with an angular focus of less than 90 degrees between said positions of said generating means.
Claim 29
Dependent Claim
45 words
The apparatus of claim 22, wherein certain ones of said generating means are angularly arranged about said heating chamber such that the microwaves are focused into said heating chamber with an angular focus of less than 90 degrees between said positions of said generating means.
Claim 30
Dependent Claim
28 words
The apparatus of claim 25, wherein each generating means generates microwaves having an angular spread of approximately between 30 and 40 degrees as directed into said heating chamber.
Claim 31
Dependent Claim
28 words
The apparatus of claim 23, wherein each generating means generates microwaves having an angular spread of approximately between 30 and 40 degrees as directed into said heating chamber.
Claim 32
Dependent Claim
28 words
The apparatus of claim 22, wherein each generating means generates microwaves having an angular spread of approximately between 30 and 40 degrees as directed into said heating chamber.
Claim 33
Dependent Claim
28 words
The apparatus of claim 20, wherein each generating means generates microwaves having an angular spread of approximately between 30 and 40 degrees as directed into said heating chamber.
Claim 34
Dependent Claim
22 words
The apparatus of claim 20, wherein said heating chamber is defined in a portion thereof by walls that form a conical-type configuration.
Claim 35
Dependent Claim
23 words
The apparatus of claim 20, wherein said heating chamber is defined in a portion thereof by walls that form a substantially pyramidal shape.
Claim 36
Dependent Claim
16 words
The apparatus of claim 23, wherein said circuit means includes at least one voltage doubler circuit.
Claim 37
Dependent Claim
24 words
The apparatus of claim 20, wherein said generating means includes a plurality of magnetrons each having a power output generally not exceeding 800 watts.
Claim 38
Dependent Claim
45 words
A microwave heating and drying chamber in accordance with the method of claim 7, having a plurality of microwave propagating sources having at least two sources of which provide substantially opposite planar propagation of microwaves, and a portion of which defines a substantially pyramidal configuration.
Claim 39
Dependent Claim
14 words
The microwave heating chamber of claim 35, having at least four microwave propagating sources.
Claim 40
Dependent Claim
44 words
A microwave heating and drying chamber in accordance with the method of claim 7, having a plurality of microwave propagating sources having at least two sources of which provide substantially opposite planar propagation of microwaves, and a portion of which defines a conical-type configuration.
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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) | 1992-01-03 | 1992-07-04 | 1993-01-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-01-03 | 1996-07-04 | 1997-01-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-01-03 | 2000-07-04 | 2001-01-03 | $7700.00 | Window Closed / Lapsed |