CA1118845A - Method of automatic matching of the microwave heater - Google Patents
Method of automatic matching of the microwave heaterInfo
- Publication number
- CA1118845A CA1118845A CA000329622A CA329622A CA1118845A CA 1118845 A CA1118845 A CA 1118845A CA 000329622 A CA000329622 A CA 000329622A CA 329622 A CA329622 A CA 329622A CA 1118845 A CA1118845 A CA 1118845A
- Authority
- CA
- Canada
- Prior art keywords
- microwave
- tuning
- microwave energy
- reflected
- load
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 238000000034 method Methods 0.000 title claims abstract description 12
- 238000011282 treatment Methods 0.000 claims abstract description 13
- 238000010521 absorption reaction Methods 0.000 claims abstract description 10
- 230000005540 biological transmission Effects 0.000 claims description 2
- 238000010438 heat treatment Methods 0.000 abstract description 2
- 238000009434 installation Methods 0.000 description 4
- 239000000523 sample Substances 0.000 description 4
- 230000008878 coupling Effects 0.000 description 2
- 238000010168 coupling process Methods 0.000 description 2
- 238000005859 coupling reaction Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 230000009466 transformation Effects 0.000 description 2
- 241000479907 Devia <beetle> Species 0.000 description 1
- 241000973252 Diagramma Species 0.000 description 1
- 244000228957 Ferula foetida Species 0.000 description 1
- 241000183024 Populus tremula Species 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B6/00—Heating by electric, magnetic or electromagnetic fields
- H05B6/64—Heating using microwaves
- H05B6/78—Arrangements for continuous movement of material
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B6/00—Heating by electric, magnetic or electromagnetic fields
- H05B6/64—Heating using microwaves
- H05B6/66—Circuits
- H05B6/666—Safety circuits
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Constitution Of High-Frequency Heating (AREA)
- Control Of High-Frequency Heating Circuits (AREA)
- Heating, Cooling, Or Curing Plastics Or The Like In General (AREA)
Abstract
INVENTION OF
Gerd Naumann and Bernd Treine TITLE OF THE INVENTION
"Improvements relating to microwave heating"
ABSTRACT OF THE DISCLOSURE
A method and apparatus for matching a microwave heater to reduce the microwave energy reflected by the load, wherein microwave energy from a microwave energy source is supplied to a treatment chamber by a hollow waveguide of rectangular section, a directional coupler in the waveguide prevents reflected energy returning to the source and directs it to absorption means, a detector is provided at the absorption means to measure the reflected energy and produce a signal and control means is provided to operate control motors to operate tuning pins provided in the waveguide, the control motors having different operating speeds.
Gerd Naumann and Bernd Treine TITLE OF THE INVENTION
"Improvements relating to microwave heating"
ABSTRACT OF THE DISCLOSURE
A method and apparatus for matching a microwave heater to reduce the microwave energy reflected by the load, wherein microwave energy from a microwave energy source is supplied to a treatment chamber by a hollow waveguide of rectangular section, a directional coupler in the waveguide prevents reflected energy returning to the source and directs it to absorption means, a detector is provided at the absorption means to measure the reflected energy and produce a signal and control means is provided to operate control motors to operate tuning pins provided in the waveguide, the control motors having different operating speeds.
Description
The invcntion rela~es to a method and apparatus for diclectlic heating by means o~ microwave.erler~y.
It .is known that, ln ordcr to achieve a high degree o~
efficiency for a microwave heater, ~he load mus~ be matched to the microwave generator and its waveguide, as the microwave generator, the energy waveguide, the treatment chamber and the load may have different impedances. If the impedances of the microwava generator, the waveguide and the treatment chamber on the one hand and the impedance of ~he load on the other hand are di~erent~
transformation means must be interposed between them, the purpose of the transformation means being to match the impedance of the load to the impedance of the microwave generator wi~h the wave guide and the treatment chamber. Optimum utilisation of the microwave energy is ensured only when the entire quantity of energy produced in the microwave generator is converted to heat in the load. This means that as far as possible, there should no~ be any reflection of the microwave energy at the load.
In order to provide for low-reflection matching of the load, it has been proposed to provide ona or more tuning pins or tuning screws to project displaceably into the wayeguide, which waveguide ay be in the form of a hollow waveguide passage. With such tuning members which act as a matching transfonner, it is theoretically possible for any load impedance to be matched to any generator impedance.
It has been found thak the impedance o~ the load is variable, in operation o~ a microwave heater. Therefore, it is not sufficient ior the loa~ to be matched to the microwave generator by way of the tuning mernbers, Just once. There is thereiore a requirement for automatlc matching o~ the rnicrowave heater during operfltion thereo~.
This automatic matchin~ operation is intcndcd to reduce to a minimum ~he amounk o~ microwave energy which ls re~lected by ~he load, as a result o de~ectlve matt:hing.
It has already been proposed that the microwave energy reilt-~c~ed by the load rrlfly be me~sured and the ~uning rnembers adjusted in 3S accordancc with the measured value) in order to reducc to a millimun the microwave en~rgy which i8 reilected by the load. ~owever~ it is , ' ~
`
S
not po3slble to give a clear adjustn~nt instruc~ion9 over a large r2nge of variation of the re~lection coefficient.
Thc inven~ion is based on the problem of providing a method of matching a microwave heater, which is distinguished by a wide ~uning range and ex~reMely precise matclling o the load to the microwave generator.
According to one aspe~t of the invention9 there is provided a method of ma~ching a microwave heater, for the purposes of reduclng microwave energy re~lected by the load wherein microwave energy is supplied to a treatment chamber from a microwave energy source by way of a hollow waveguide of substantially square or rectangular cross section and matching is ef~ected by means of adjustable tuning members which are disposed in the hollow wave-guide, the method comprising measuring the microwave energy reflected by the load, and, when a given level of reflected micro~ave energy is exceeded, adjusting two tuning members wlth one oi the tuning members having a higher adjustment syeed than the other.
If, when the reflected microwave energy is meAsured, it is found that an admissible level has been exceeded, the tuning members are adjusted at different speeds until the microwave installation is again tuned to such an extent that the reflected microwave energy is reduced to the desired minimum.
Advantageously, one tuning member is adjusted repeatedly through the entire tuning range, while the second tuning member is adjusted only through a partial range. While the second tuning member passes through lts ~uning range or a part thereof, the ~irst tuning member may pass through its full tuning range several times, Por example 30 times. In this wuy, the matchlng process contlnuoualy eects minimisation of the reflected microw~ve energy Wherl the minimum o~ re~lec~ed microwave energy is reached, ad~us~ment of the tuning members i8 gtopped.
Such a method can have the important advantage oE providing a mat:clllng process which i9 convergent ln any load range.
3S According to another aspect of the invention, there is provided a mic~owave hea~er including matchlng means ~or reduclng .i'`...
~. .
~.. ,,........ .. .. . . .......................................................... ..... ........... ................................................. ~
the mi.crowave energy reflectcd by thc load and comprising a treat-ment chamber connected to a microwave generator by way of a hollow waveguide o~ substcmtially square or rectangular cross-section, displaceable tuning pins disposed in the hollow waveguide, a cir-culatol or directional coupler whicl~ blocks, ~rom the microwavegenerator, the microwave energy refl.ected by the load, and ].eads ; to absorption means, measuring means ~or the reflec~ed microwave energy disposed at ~he absorption means~ sw:Ltching means for converting the rneasured value in~o a proportional electrical signal and connccted to the output of the measuring means, and an amplifier circuit to compare the electricaL signal wi~h a desired value to produce an output signal which is applied to control members ior actuating control motors of the tuning pins, the control motors having different speeds.
~dvantageously, the control motors are connected to the tuning members by way of crank transmission means.
I~hen the reElected microwave energy devia~es from a predeter-mined minimum~ the tuning pins are automatically displaced at difierent speeds until the measured reflected microwave energy has again been restored to the minimum value.
It is known that, with a three-part tuning transformer whose tuning mcmbers have ~/4-spacings, any defective matching of a micro-wave install.ation can be eliminated (Meinke/gu~dlach, 1968, page 420).
If the predetermined minim~m of reflected microwave energy cannot be attained by means of two tuning members, a third tuning member can carry out the same tuning process, with tha~ one of the other tuning members which is at the ~/4-spacing. In this case, the tuning mernber which is at the ~/2-spacing is retracted into a ~tarting posikion. This mode o~ operation can ensure~ a~ter a double ~unlng period, that the installation is matched.
It i8 thus pos~ible to provlde for matching o~ a microwave systeml wherein the use~ul power from the microwave generator i9 al~o applied almost entirely ~o the load, in operation of the microwave ins~all.atioll.
3S The invention 19 diogrammatic~lly illustrated by way oE
example in ~he flCCOInpanyillg drawing, 1TI WLIiCh :
~1~L8~3~5 Figure 1 show9 a diagramma~ic view of a microwave heater with control means for ~atching the microwave heater; and ~igure 2 shows the potential gradient of the detec~or S probe which receives the reflected microwave energy, in automatic matching oi the microwave heater.
Referring to the drawing~ a treatment chamber of a micro-wave heater is formed wi~h a l~icrowave treatment passage 3 o~
approximately square cross-section. Elongate material to be heated~ comprising for example, rubber, i5 passed through the passage 3.
The microwave energy is introduced into the treatment chamber 3 at two coupling stations 4 and 5. Each coupling station 4 and 5 is connected to a respective microwave generator 6 and 7 by way oi a respective hollow waveguid2 8 and 9 oi square cross-section. The waveguides 8 and 9 which terminate at the treatment chamber 3 are displaced at 90 relative to each other~ The introduction of the microwave energy, at positions which are displaced thro~lgh 90 re]ative to each othe~, causes the produc-tion of two TE10-waves which are turned througb 90. In this way, there is a favourable energy absorption angle between the profile lip and the E-field line, for dif~erent profiles of the elongate material to be heated.
A matching transormer 11 and l2 is disposed at each of the waveguides 8 and 9 which carry the microwave energy, each such transformer comprising three tuning pins 13, 14 and 15. A
directional coupler such as a circulator 16 and 17 is connected between the respective trans~ormer ll and 12 and the associated microwave generator 6 and 7 and passcs the microwave energy re~lected by the load to an absorption means where the reELected microwave energy is consumed. The absorption means is provided wil:h measuring means comprising an antenna and a detector probe 18.
This arrangement there~ore produces an electri~al signal U which is proportionfll to the re~lected microwave energy and which is applied to two comparators l9 and 21. A reference signal U ref .
.
is also appliecl to e~ch of che comparators 19 and 21 respectively.
If the voltage U produced by the probe 18 exceeds ~he voltage U ref of the reference signal, a signal Q is applied by way of the first comparator 19 to control means 22 for control motors Ml and M2. The control motors Ml and M2 are each coupled to a respective tuning pin 15 and 14 preferably by crank transmissioTl means. In operation~ the tuning pin 14 is displaced in a high-speed mode and the tuning pin 15 is displaced only slowly by its control motor Ml.
If matching of the microwave installation has not been achieved within a given yeriod of time, which period is determined by a timing member integrated in ~he comparator 19, a signal Q is used. This signal Q is applied to the second compara~or 21 and to resetting means 23 for the motor Ml of the tuning pin 15.
The second comparator 21 applies a signal to control means 24 for the motor M2 snd a motor M3 for the tuning pins 13 and 14 respectively. The tuning pins 13 and 14 carry out the same matching operation while the tuning pin 15 is returned to a starting position.
~hen the detector probe voltage and thus the reflected microwave energy fall below a predetermi.ned level U min, the inpu~ signal to the comparators 19 and 21 falls below a switch-off threshold. The comparators 19 and 21 no longer produce an output signal for energising the control motors. The micro-wave installation is thus matched for the opera~ing condition at that time.
Figure 2 shows the potential gradient in respec~ of minimisation of voltage and thus minimisation of the reflected mlcrowave energy ~en using direct~current motors, it is possible that the high-spee.d mode of movement o~ the one tuning pin may cnuse the tunlng pin to go beyond the minimum. The switchin~ means can then be provided wi~.h a means which makcs it possible for the tunlng pin to be reversed in its setl:ing, in such a case. If the tuning pins are displaced by means of s~epping motors, then the voltage will not pass through the minimum voltage value.
, .
, .. .............. . . .. . . . . .... .
~ -- ~ :
It .is known that, ln ordcr to achieve a high degree o~
efficiency for a microwave heater, ~he load mus~ be matched to the microwave generator and its waveguide, as the microwave generator, the energy waveguide, the treatment chamber and the load may have different impedances. If the impedances of the microwava generator, the waveguide and the treatment chamber on the one hand and the impedance of ~he load on the other hand are di~erent~
transformation means must be interposed between them, the purpose of the transformation means being to match the impedance of the load to the impedance of the microwave generator wi~h the wave guide and the treatment chamber. Optimum utilisation of the microwave energy is ensured only when the entire quantity of energy produced in the microwave generator is converted to heat in the load. This means that as far as possible, there should no~ be any reflection of the microwave energy at the load.
In order to provide for low-reflection matching of the load, it has been proposed to provide ona or more tuning pins or tuning screws to project displaceably into the wayeguide, which waveguide ay be in the form of a hollow waveguide passage. With such tuning members which act as a matching transfonner, it is theoretically possible for any load impedance to be matched to any generator impedance.
It has been found thak the impedance o~ the load is variable, in operation o~ a microwave heater. Therefore, it is not sufficient ior the loa~ to be matched to the microwave generator by way of the tuning mernbers, Just once. There is thereiore a requirement for automatlc matching o~ the rnicrowave heater during operfltion thereo~.
This automatic matchin~ operation is intcndcd to reduce to a minimum ~he amounk o~ microwave energy which ls re~lected by ~he load, as a result o de~ectlve matt:hing.
It has already been proposed that the microwave energy reilt-~c~ed by the load rrlfly be me~sured and the ~uning rnembers adjusted in 3S accordancc with the measured value) in order to reducc to a millimun the microwave en~rgy which i8 reilected by the load. ~owever~ it is , ' ~
`
S
not po3slble to give a clear adjustn~nt instruc~ion9 over a large r2nge of variation of the re~lection coefficient.
Thc inven~ion is based on the problem of providing a method of matching a microwave heater, which is distinguished by a wide ~uning range and ex~reMely precise matclling o the load to the microwave generator.
According to one aspe~t of the invention9 there is provided a method of ma~ching a microwave heater, for the purposes of reduclng microwave energy re~lected by the load wherein microwave energy is supplied to a treatment chamber from a microwave energy source by way of a hollow waveguide of substantially square or rectangular cross section and matching is ef~ected by means of adjustable tuning members which are disposed in the hollow wave-guide, the method comprising measuring the microwave energy reflected by the load, and, when a given level of reflected micro~ave energy is exceeded, adjusting two tuning members wlth one oi the tuning members having a higher adjustment syeed than the other.
If, when the reflected microwave energy is meAsured, it is found that an admissible level has been exceeded, the tuning members are adjusted at different speeds until the microwave installation is again tuned to such an extent that the reflected microwave energy is reduced to the desired minimum.
Advantageously, one tuning member is adjusted repeatedly through the entire tuning range, while the second tuning member is adjusted only through a partial range. While the second tuning member passes through lts ~uning range or a part thereof, the ~irst tuning member may pass through its full tuning range several times, Por example 30 times. In this wuy, the matchlng process contlnuoualy eects minimisation of the reflected microw~ve energy Wherl the minimum o~ re~lec~ed microwave energy is reached, ad~us~ment of the tuning members i8 gtopped.
Such a method can have the important advantage oE providing a mat:clllng process which i9 convergent ln any load range.
3S According to another aspect of the invention, there is provided a mic~owave hea~er including matchlng means ~or reduclng .i'`...
~. .
~.. ,,........ .. .. . . .......................................................... ..... ........... ................................................. ~
the mi.crowave energy reflectcd by thc load and comprising a treat-ment chamber connected to a microwave generator by way of a hollow waveguide o~ substcmtially square or rectangular cross-section, displaceable tuning pins disposed in the hollow waveguide, a cir-culatol or directional coupler whicl~ blocks, ~rom the microwavegenerator, the microwave energy refl.ected by the load, and ].eads ; to absorption means, measuring means ~or the reflec~ed microwave energy disposed at ~he absorption means~ sw:Ltching means for converting the rneasured value in~o a proportional electrical signal and connccted to the output of the measuring means, and an amplifier circuit to compare the electricaL signal wi~h a desired value to produce an output signal which is applied to control members ior actuating control motors of the tuning pins, the control motors having different speeds.
~dvantageously, the control motors are connected to the tuning members by way of crank transmission means.
I~hen the reElected microwave energy devia~es from a predeter-mined minimum~ the tuning pins are automatically displaced at difierent speeds until the measured reflected microwave energy has again been restored to the minimum value.
It is known that, with a three-part tuning transformer whose tuning mcmbers have ~/4-spacings, any defective matching of a micro-wave install.ation can be eliminated (Meinke/gu~dlach, 1968, page 420).
If the predetermined minim~m of reflected microwave energy cannot be attained by means of two tuning members, a third tuning member can carry out the same tuning process, with tha~ one of the other tuning members which is at the ~/4-spacing. In this case, the tuning mernber which is at the ~/2-spacing is retracted into a ~tarting posikion. This mode o~ operation can ensure~ a~ter a double ~unlng period, that the installation is matched.
It i8 thus pos~ible to provlde for matching o~ a microwave systeml wherein the use~ul power from the microwave generator i9 al~o applied almost entirely ~o the load, in operation of the microwave ins~all.atioll.
3S The invention 19 diogrammatic~lly illustrated by way oE
example in ~he flCCOInpanyillg drawing, 1TI WLIiCh :
~1~L8~3~5 Figure 1 show9 a diagramma~ic view of a microwave heater with control means for ~atching the microwave heater; and ~igure 2 shows the potential gradient of the detec~or S probe which receives the reflected microwave energy, in automatic matching oi the microwave heater.
Referring to the drawing~ a treatment chamber of a micro-wave heater is formed wi~h a l~icrowave treatment passage 3 o~
approximately square cross-section. Elongate material to be heated~ comprising for example, rubber, i5 passed through the passage 3.
The microwave energy is introduced into the treatment chamber 3 at two coupling stations 4 and 5. Each coupling station 4 and 5 is connected to a respective microwave generator 6 and 7 by way oi a respective hollow waveguid2 8 and 9 oi square cross-section. The waveguides 8 and 9 which terminate at the treatment chamber 3 are displaced at 90 relative to each other~ The introduction of the microwave energy, at positions which are displaced thro~lgh 90 re]ative to each othe~, causes the produc-tion of two TE10-waves which are turned througb 90. In this way, there is a favourable energy absorption angle between the profile lip and the E-field line, for dif~erent profiles of the elongate material to be heated.
A matching transormer 11 and l2 is disposed at each of the waveguides 8 and 9 which carry the microwave energy, each such transformer comprising three tuning pins 13, 14 and 15. A
directional coupler such as a circulator 16 and 17 is connected between the respective trans~ormer ll and 12 and the associated microwave generator 6 and 7 and passcs the microwave energy re~lected by the load to an absorption means where the reELected microwave energy is consumed. The absorption means is provided wil:h measuring means comprising an antenna and a detector probe 18.
This arrangement there~ore produces an electri~al signal U which is proportionfll to the re~lected microwave energy and which is applied to two comparators l9 and 21. A reference signal U ref .
.
is also appliecl to e~ch of che comparators 19 and 21 respectively.
If the voltage U produced by the probe 18 exceeds ~he voltage U ref of the reference signal, a signal Q is applied by way of the first comparator 19 to control means 22 for control motors Ml and M2. The control motors Ml and M2 are each coupled to a respective tuning pin 15 and 14 preferably by crank transmissioTl means. In operation~ the tuning pin 14 is displaced in a high-speed mode and the tuning pin 15 is displaced only slowly by its control motor Ml.
If matching of the microwave installation has not been achieved within a given yeriod of time, which period is determined by a timing member integrated in ~he comparator 19, a signal Q is used. This signal Q is applied to the second compara~or 21 and to resetting means 23 for the motor Ml of the tuning pin 15.
The second comparator 21 applies a signal to control means 24 for the motor M2 snd a motor M3 for the tuning pins 13 and 14 respectively. The tuning pins 13 and 14 carry out the same matching operation while the tuning pin 15 is returned to a starting position.
~hen the detector probe voltage and thus the reflected microwave energy fall below a predetermi.ned level U min, the inpu~ signal to the comparators 19 and 21 falls below a switch-off threshold. The comparators 19 and 21 no longer produce an output signal for energising the control motors. The micro-wave installation is thus matched for the opera~ing condition at that time.
Figure 2 shows the potential gradient in respec~ of minimisation of voltage and thus minimisation of the reflected mlcrowave energy ~en using direct~current motors, it is possible that the high-spee.d mode of movement o~ the one tuning pin may cnuse the tunlng pin to go beyond the minimum. The switchin~ means can then be provided wi~.h a means which makcs it possible for the tunlng pin to be reversed in its setl:ing, in such a case. If the tuning pins are displaced by means of s~epping motors, then the voltage will not pass through the minimum voltage value.
, .
, .. .............. . . .. . . . . .... .
~ -- ~ :
Claims (4)
1 A method of matching a microwave heater, for the purpose of reducing microwave energy reflected by the load wherein microwave energy is supplied to a treatment chamber from a microwave energy source by way of a hollow waveguide of substantially rectangular cross-section and matching is effected by means of adjustable tuning members which are disposed in said hollow waveguide, the method comprising measuring the microwave energy reflected by the load and, when a given level of reflected microwave energy is exceeded, adjusting two tuning members with one of the tuning members having a higher adjustment speed than the other.
2 The invention claimed in claim 1, wherein a first of said tuning members is adjusted repeatedly through its full tuning range, while a second of said tuning members is adjusted through only a part of its range.
3 A microwave heater including matching means for reducing the microwave energy reflected by the load and comprising a treatment chamber; a microwave generator; a hollow waveguide of substantially rectangular cross-section connecting said micro-wave generator to said treatment chamber, displaceable tuning pins disposed in said hollow waveguide; a directional coupler to block, Prom the microwave generator, the microwave. energy reflected by the load; absorption means to absorb said reflected microwave energy directed to said absorption means by said directional coupler; measuring means, disposed at said absorption means, to measure said reflected microwave energy; switching means connected to the output of said measuring means, to convert the measured value measured by said measuring means into a proportional electrical signal; an amplifier circuit .
to compare said electrical signal with a desired value and produce an output signal; control members to which said output signal is applied; and control motors for said tuning pins, said control motors being actuated by said control members and having different operating speeds.
to compare said electrical signal with a desired value and produce an output signal; control members to which said output signal is applied; and control motors for said tuning pins, said control motors being actuated by said control members and having different operating speeds.
4 The invention claimed in claim 3, further comprising crank transmission means connecting said control motors to said tuning pins.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19782825944 DE2825944C3 (en) | 1978-06-14 | 1978-06-14 | Method and device for dielectric heating by means of microwave energy |
| DEP2825944.1 | 1978-06-14 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1118845A true CA1118845A (en) | 1982-02-23 |
Family
ID=6041707
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000329622A Expired CA1118845A (en) | 1978-06-14 | 1979-06-13 | Method of automatic matching of the microwave heater |
Country Status (6)
| Country | Link |
|---|---|
| JP (1) | JPS5533785A (en) |
| CA (1) | CA1118845A (en) |
| DE (1) | DE2825944C3 (en) |
| FR (1) | FR2434544A1 (en) |
| GB (1) | GB2023313B (en) |
| SE (1) | SE438234B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10603617B2 (en) | 2015-10-30 | 2020-03-31 | Fujitsu Limited | Microwave irradiation apparatus and exhaust gas purification apparatus |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS56159085A (en) * | 1980-05-13 | 1981-12-08 | Matsushita Electric Ind Co Ltd | High frequency heater |
| JPS56159086A (en) * | 1980-05-13 | 1981-12-08 | Matsushita Electric Ind Co Ltd | High frequency heater |
| JPS5723494A (en) * | 1980-07-18 | 1982-02-06 | Nippon Electric Co | High frequency heater |
| JPS58111295A (en) * | 1981-12-25 | 1983-07-02 | 株式会社東芝 | High frequency heater |
| EP0088175A1 (en) * | 1982-03-08 | 1983-09-14 | Douglas Powell Mahan | Tumble drying apparatus |
| JP4783429B2 (en) | 2006-07-06 | 2011-09-28 | 株式会社瑞光 | Wound dressing |
| JP4939900B2 (en) * | 2006-11-02 | 2012-05-30 | 白十字株式会社 | Wound dressing |
| JP4939903B2 (en) * | 2006-11-07 | 2012-05-30 | 白十字株式会社 | Wound dressing |
| US10980088B2 (en) | 2018-01-22 | 2021-04-13 | Markov Llc | Energy absorption monitoring for an intelligent electronic oven with energy steering |
| DE102018115827A1 (en) * | 2018-06-29 | 2020-01-02 | Gerlach Maschinenbau Gmbh | Device for networking with controlled microwaves |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2499182A (en) * | 1946-10-08 | 1950-02-28 | Gen Electric | Automatic maximizing control system |
| DE1221348B (en) * | 1962-04-10 | 1966-07-21 | Rohde & Schwarz | Method and arrangement for independent coordination of electrical networks |
| US3757070A (en) * | 1972-06-19 | 1973-09-04 | Canadian Patents Dev | Microwave heating apparatus with tuning means |
| GB1400895A (en) * | 1973-06-27 | 1975-07-16 | Canadian Patents Dev | Microwave heating apparatus |
| US4035599A (en) * | 1976-02-23 | 1977-07-12 | Canadian Patents And Development Limited | Control system for non-resonant microwave dryers |
| FR2358052A1 (en) * | 1976-07-07 | 1978-02-03 | Thomson Csf | UHF oscillator load variation compensation - is applied to klystron powered furnaces and has piston controlled auxiliary cavity |
-
1978
- 1978-06-14 DE DE19782825944 patent/DE2825944C3/en not_active Expired
-
1979
- 1979-06-07 FR FR7914527A patent/FR2434544A1/en active Granted
- 1979-06-12 GB GB7920371A patent/GB2023313B/en not_active Expired
- 1979-06-13 SE SE7905219A patent/SE438234B/en not_active IP Right Cessation
- 1979-06-13 CA CA000329622A patent/CA1118845A/en not_active Expired
- 1979-06-14 JP JP7409879A patent/JPS5533785A/en active Granted
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10603617B2 (en) | 2015-10-30 | 2020-03-31 | Fujitsu Limited | Microwave irradiation apparatus and exhaust gas purification apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2023313A (en) | 1979-12-28 |
| DE2825944C3 (en) | 1981-10-22 |
| JPS5533785A (en) | 1980-03-10 |
| JPS6226158B2 (en) | 1987-06-06 |
| SE7905219L (en) | 1979-12-15 |
| DE2825944B2 (en) | 1980-08-14 |
| SE438234B (en) | 1985-04-01 |
| FR2434544B1 (en) | 1984-02-10 |
| DE2825944A1 (en) | 1979-12-20 |
| FR2434544A1 (en) | 1980-03-21 |
| GB2023313B (en) | 1983-01-19 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA1118845A (en) | Method of automatic matching of the microwave heater | |
| CA1162615A (en) | Microwave energy heating device with two waveguides coupled side-by-side | |
| CN101502170B (en) | Microwave processing apparatus | |
| CN112558001A (en) | Pulse high-power field calibration device and method | |
| EP0171620B1 (en) | Microwave-heating apparatus | |
| US20110073592A1 (en) | Applicator for microwave enhanced chemistry | |
| Gajda et al. | An equivalent circuit of an open-ended coaxial line | |
| US4932075A (en) | High speed wide range variable rate power detector | |
| Nguyen et al. | Combination of local heating and radiometry by microwaves | |
| Solbach | Electric probe measurements on dielectric image lines in the frequency range of 26-90 GHz | |
| CN100360946C (en) | Apparatus for and method of measuring local specific absorption range SAR | |
| Sanchez et al. | Accurate theory for a new leaky‐wave antenna for millimeter waves using nonradiative dielectric waveguide | |
| GB2330508A (en) | Waveguide arrangement in a microwave oven | |
| Ohkubo et al. | Waveguide coupling during lower hybrid current drive in a tokamak | |
| Phukphan et al. | Repeatability of Programmable Waveguide Attenuators at 110-170 GHz and 220-330 GHz | |
| Kamper et al. | A new technique for RF measurements using superconductors | |
| IIDA et al. | Measurement of antenna factor of dipole antennas on a ground plane by 3-antenna method | |
| Sowa et al. | Field calibration system implementing 3-D optically modulated scatterers for immunity test site purposes | |
| Early | A wide-band wattmeter for wave guide | |
| Tiwari et al. | An efficient image guide mode launcher | |
| Chang et al. | A new applicator for efficient uniform heating using a circular cylindrical geometry | |
| Dewar et al. | Coaxial-slot surface wave launchers | |
| RU2071176C1 (en) | Direct amplification receiver | |
| Yonnone | Microwave equipment considerations for high temperature studies in ceramics | |
| Bordoni et al. | Measurement of the input impedance of a RF biased SQUID |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |