US3663783A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Safety load and temperature control system for microwave ovens
Assignee: United States Department of the Army
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Filing: 1970-12-07
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Granted: 1972-05-16
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Expires: 1990-12-07
Abstract
Abstract A safety load and temperature control system for microwave ovens wherein a variable volume of water is passed through the oven for controlling the amount of energy received by a work piece therein. Microwave energy from magnetron tubes is introduced into the oven chamber for processing a work piece. The variable supply of water within the chamber is increased for small parts being cured and decreased for large parts being cured. The water is passed through a dielectrically transparent vessel within the chamber and is heated by the microwave energy proportional to the heated work piece or part. The temperature of the water leaving the chamber is indicative of the rate of change of the work piece temperature. A temperature controller has upper and lower limits that increase or decrease the water in the chamber and passing therethrough to maintain the work piece heating rate within a desired range. The variable supply of water also serves as a dummy load to absorb excessive radiant energy, preventing destructive feedback to the magnetron tubes. Microwave filters at water inlet and outlet ports keep the high frequency energy within the chamber.
Inventors
- 👤 Elbert L Mckague Jr
- 👤 Walter C Cooper Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 04:58
CPC Classifications
H; H05; H05B; H05B6/00; H05B6/64; H05B6/80; H05B6/802; G; G05; G05D; G05D23/00; G05D23/19; G05D23/1919; H05B6/66; H05B6/666
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
149 words
A safety load and temperature control system for microwave ovens used in curing various sizes of work pieces, comprising: a microwave chamber housing having metal chamber walls for reflecting microwave energy within said chamber, a microwave emitting source within said chamber, first and second opeings through opposing chamber walls, first and second liquid conducting metal pipes external to said oven and having respective first ends thereof inserted through said openings and sealed to the inner wall of said chamber for coupling a variable volume of liquid into said chamber, means communicating with said first and second metal pipes for conveying said volume of liquid through said chamber for providing a variable safety and dummy load and temperature control for said chamber, control means for varying said volume of liquid conveyed to and from said chamber and heat responsive means for measuring the temperature of said liquid leaving said chamber.
Claim 2
Dependent Claim
149 words
A safety load and temperature control system for microwave ovens used in curing various sizes of work pieces, comprising: a microwave chamber housing having metal chamber walls for reflecting microwave energy within said chamber, a microwave emitting source within said chamber, first and second opeings through opposing chamber walls, first and second liquid conducting metal pipes external to said oven and having respective first ends thereof inserted through said openings and sealed to the inner wall of said chamber for coupling a variable volume of liquid into said chamber, means communicating with said first and second metal pipes for conveying said volume of liquid through said chamber for providing a variable safety and dummy load and temperature control for said chamber, control means for varying said volume of liquid conveyed to and from said chamber and heat responsive means for measuring the temperature of said liquid leaving said chamber.
Claim 3
Dependent Claim
84 words
A safety load control system for microwave ovens as set forth in claim 1 wherein said conveying means is a microwave frequency dielectrically transparent vessel within said chamber having dielectrically transparent input and output tubes, said input tube being joined to said first chamber wall opening and pipe therethrough for conveying said liquid into said vessel, said output tube being connected to drain said vessel and joined to said second opening and metal pipe for conveying said liquid out of said vessel and chamber.
Claim 4
Dependent Claim
30 words
A safety load control system as set forth in claim 2 wherein said heat responsive means is a thermocouple in said second metal drain pipe external to said microwave oven.
Claim 5
Dependent Claim
53 words
A safety load control system as set forth in claim 3 wherein said control means comprises an inlet control valve in said first metal pipe and an outlet control valve in said second metal pipe for increasing and decreasing the liquid volume level within said vessel for controlling the temperature within the chamber.
Claim 6
Dependent Claim
64 words
A safety load control system as set forth in claim 4 wherein said control means further comprises a control panel having a servo system control with an input connected to an output of said thermocouple for responding to said liquid temperature changes, said servo syStem having first and second outputs coupled to said input and output valves respectively for automatically operating said control valves.
Claim 7
Dependent Claim
32 words
A safety load control system as set forth in claim 5 wherein said inlet and outlet metal pipes are grounded to said microwave oven to prevent microwave energy from escaping said chamber.
Claim 8
Dependent Claim
68 words
A safety load control system as set forth in claim 5 and further comprising a metal screen forming the ends of said first and second metal pipes, said screens having a plurality of holes therein, said holes having a diameter less than a quarter of a wave length of the microwave energy from said source, and wherein said liquid is water and said vessel and tubes are glass.
Claim 9
Dependent Claim
90 words
A safety load control system as set forth in claim 1 wherein said liquid is water and further comprising a plurality of dielectric transparent vessels within said chamber, a plurality of input and output metal pipes communicating into said chamber for conveying water into and out of respective said vessels, metal inlet and exit water reservoirs adjacent said oven and connected to said metal pipes for conveying water to and from said microwave chamber while absorbing energy leakage from said chamber, and said vessels being tubular glass of unequal diameter.
Claim 10
Dependent Claim
102 words
A safety load control system as set forth in claim 3 and further comprising a flexible hose connected to the other or drain end of said second metal pipe for draining said vessel, a motor driven elevator screw connected for raising and lowering said hose to restrict or promote liquid flow therethrough, a support post for said elevator screw and a transparent stand pipe connected in said hose at the apex of the hose for indicating the volume of water within said chamber, and said control means being responsive to an output signal of said thermocouple for activating said motor driven screw.
Claim 11
Dependent Claim
50 words
A safety load control system as set forth in claim 9 wherein said liquid is water and said vessel and tubes are glass, said outlet tube and metal pipe having a diameter that provides a drainage rate greater than the input filling rate of the vessel for gravity drainage thereof.
Claim 12
Independent Claim
132 words
The method of curing various sizes of work pieces within a microwave oven that provides a variable safety load and temperature control system for the oven, said oven including a curing chamber and a dielectrically transparent vessel within said chamber, comprising the steps of: placing a work piece to be cured within said oven chamber, passing a liquid through said vessel for providing a dummy or safety load within said chamber, radiating microwave energy into said chamber for curing said work piece, measuring the temperature of liquid exiting said chamber, and adjusting the volume of said liquid passing through the chamber in response to variations in the measured temperature for providing a safety load that absorbs excessive radiant energy and controls the rate of heating of said work piece within said chamber.
Claim 13
Independent Claim
132 words
The method of curing various sizes of work pieces within a microwave oven that provides a variable safety load and temperature control system for the oven, said oven including a curing chamber and a dielectrically transparent vessel within said chamber, comprising the steps of: placing a work piece to be cured within said oven chamber, passing a liquid through said vessel for providing a dummy or safety load within said chamber, radiating microwave energy into said chamber for curing said work piece, measuring the temperature of liquid exiting said chamber, and adjusting the volume of said liquid passing through the chamber in response to variations in the measured temperature for providing a safety load that absorbs excessive radiant energy and controls the rate of heating of said work piece within said chamber.
Claim 14
Dependent Claim
63 words
The method of heating work pieces within a microwave oven that provides a variable safety load and temperature control as set forth in claim 11, comprising the steps of: increasing and decreasing the volume of said liquid passing through the chamber in response to respective increases and decreases of the measured temperature, and passing water through said vessel for providing said safety load.
Claim 15
Dependent Claim
74 words
The method of heating work pieces within a microwave oven that provides a variable safety load and temperature control as set forth in claim 12, comprising the steps of: injecting water into said vessel for providing said safety load, gravity draining said water from said vessel and chamber, restricting and promoting water flow from said vessel by elevating or lowering the gravity flow level from said chamber in response to said measured temperature variations.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-05-16 | 1975-11-15 | 1976-05-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-16 | 1979-11-15 | 1980-05-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-16 | 1983-11-15 | 1984-05-16 | $7700.00 | Window Closed / Lapsed |