EP0759263A1 - A device for homogenizing the distribution of radiatons within the cooking space of a microwave oven - Google Patents
A device for homogenizing the distribution of radiatons within the cooking space of a microwave ovenInfo
- Publication number
- EP0759263A1 EP0759263A1 EP95918143A EP95918143A EP0759263A1 EP 0759263 A1 EP0759263 A1 EP 0759263A1 EP 95918143 A EP95918143 A EP 95918143A EP 95918143 A EP95918143 A EP 95918143A EP 0759263 A1 EP0759263 A1 EP 0759263A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- prechamber
- opening
- section
- face
- cooking space
- 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.)
- Granted
Links
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
- H05B6/74—Mode transformers or mode stirrers
Definitions
- the present invention relates to microwave ovens, and in particular to a device for homogenizing the distribution of the microwaves within the cooking space.
- a microwave oven includes a microwave-emitting device (magnetron) which emits radiations at a specific frequency, e.g. 2450 MHz according to the rules in force in Italy.
- the magnetron antenna emitting said radiations may be placed directly inside the cooking space of the oven, but it is more common that it emits the radiations within a waveguide which conveys them up to the apertures for the inlet into the cooking space.
- the propagation of the radiations along the waveguide takes place with the waves in phase (monomode) for conveying efficiency reasons, but a homogeneous distribution of the radiated energy is necessary in the cooking space to achieve a uniform heating of the food.
- a relative motion is generated between the food and the waves impinging thereon. This motion may be obtained by means of a rotating dish on which the food is placed, or by means of a metallic "fan” (wave scrambler) which spreads the microwaves upon entrance in the cooking space, or finally by having the magnetron antenna rotate in case it is directly inserted inside the cooking space.
- the object of the present invention is to provide a device - 2 -
- the first apparent advantage of the device according to the invention is to eliminate a mechanism potentially subject to failure by replacing it with a fixed structure which thus provides an absolute reliability.
- a second advantage stemming from the first one is the longer life of the magnetron always operating in the same conditions, whereby it does not risk damages in case of failure of the wave scrambler.
- a further advantage of the present device is the reduction in the oven cost thanks to the elimination of the rotation mechanism, whichever may be.
- Fig.1 is a schematic, partially see-through, rear view of a microwave oven provided with a device according to the invention
- Fig.2 is a side view of the upper part of the device from the side of entrance of the microwaves
- Fiq.6 is a sectional side view of the lower part of the device along line B-B of fig.5.
- a device is positioned on top of the oven at the center of the cooking space roof.
- This device includes a substantially parallelepipedal upper part called "mixing prechamber" 1, and a substantially flat lower part consisting in a fixing flange 2.
- the magnetron 3 is directly mounted on prechamber 1 with the antenna 4 inserted therein, but it is clear that the following description is suitable also for the case in which magnetron 3 is spaced from prechamber 1 and connected thereto through a conventional waveguide.
- figs.2, 3 and 4 the shape of prechamber 1 is illustrated in detail.
- fig.2 there is seen that it has a circular opening 6 on one face 5 for inserting the antenna 4 of magnetron 3, as well as two ears 7 for securing the latter. Opening 6 is centered on the mid-line with a diameter approximately equal to half of the width of face 5, its top being aligned with the lower edge of a 45° bevelling 8 located at the inner top of the opposite face 9 (fig.4).
- the plan view of fig.3 and the dotted lines of fig.2 show that said bevelling 8 is also present on the other two faces aside opening 6, but it is absent above the latter at the inner top of face 5.
- the plan view also clearly shows a lower peripheral lip 10 provided with a series of bores 11 for the coupling with the underlying fixing flange 2.
- the inner cross-section of prechamber 1 is rectangular with the short sides, on faces 5 and 9, which have a difference from the long sides not greater than 10% of their length.
- the long sides also have a slight convergence towards face 9, with a conicity of about 2°.
- the inner height of prechamber 1 is about 1.5 times the short side, and it has a slight downwards slope of about 1 ° when moving from face 5 to face 9. It may be considered, as a mere example, that the inner size of the illustrated prechamber 1 is 68 x 73 mm, with an height of 96 mm.
- flange 2 has an inner rectangular section on the upper side having a size some millimeters larger than that of prechamber 1 (in the illustrated example 75 x 80 mm) so as to allow the insertion of the latter.
- Prechamber 1 is obviously fixed by means of screws passing through a series of bores 12 corresponding to bores 11 and formed in a peripheral lip 13 similar to lip 10.
- Flange 2 has a central circular opening 14 for the passage of the microwaves, which has an upper diameter 15 equal to the short side of the inner section of flange 2 (75 mm in the example) and a lower diameter 16 equal to the short side of the inner section of prechamber 1 (68 mm in the example). Therefore, opening 14 for the passage of the microwaves into the cooking space has an area lower than that of the inner section of prechamber 1 , namely equal to the area of the circle inscribed in said inner section.
- Opening 14 is closed by a quartz glass which separates prechamber 1 from the cooking space, thus making the cleaning thereof easier, and prevents the cooking vapours from causing encrustations inside prechamber 1.
- prechamber 1 and of the relevant flange 2 may be varied somewhat, as long as the cross-section of prechamber 1 remains generally prismatic with a bevelling 8 at the inner top thereof and opening 14 has an area smaller than the relevant section of prechamber 1.
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Constitution Of High-Frequency Heating (AREA)
- Electric Ovens (AREA)
Abstract
Description
Claims
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
ITMI940908A IT1269728B (en) | 1994-05-09 | 1994-05-09 | DEVICE TO MAKE THE DISTRIBUTION OF RADIATIONS IN THE COOKING COMPARTMENT OF A MICROWAVE OVEN HOMOGENEOUS |
ITMI940908 | 1994-05-09 | ||
PCT/IT1995/000068 WO1995031085A1 (en) | 1994-05-09 | 1995-05-05 | A device for homogenizing the distribution of radiatons within the cooking space of a microwave oven |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0759263A1 true EP0759263A1 (en) | 1997-02-26 |
EP0759263B1 EP0759263B1 (en) | 1997-11-19 |
Family
ID=11368860
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP95918143A Expired - Lifetime EP0759263B1 (en) | 1994-05-09 | 1995-05-05 | A device for homogenizing the distribution of radiatons within the cooking space of a microwave oven |
Country Status (6)
Country | Link |
---|---|
EP (1) | EP0759263B1 (en) |
AU (1) | AU684024B2 (en) |
DE (1) | DE69501083T2 (en) |
ES (1) | ES2110847T3 (en) |
IT (1) | IT1269728B (en) |
WO (1) | WO1995031085A1 (en) |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3764770A (en) * | 1972-05-03 | 1973-10-09 | Sage Laboratories | Microwave oven |
KR900003489B1 (en) * | 1987-03-14 | 1990-05-19 | 삼성전자 주식회사 | Equivalent heating device of microwave range |
GB2212368A (en) * | 1987-11-24 | 1989-07-19 | Imarflex Mfg | High-frequency energy cooking devices |
JP2614336B2 (en) * | 1989-11-24 | 1997-05-28 | 株式会社東芝 | High frequency cooking device |
-
1994
- 1994-05-09 IT ITMI940908A patent/IT1269728B/en active IP Right Grant
-
1995
- 1995-05-05 ES ES95918143T patent/ES2110847T3/en not_active Expired - Lifetime
- 1995-05-05 DE DE69501083T patent/DE69501083T2/en not_active Expired - Fee Related
- 1995-05-05 EP EP95918143A patent/EP0759263B1/en not_active Expired - Lifetime
- 1995-05-05 WO PCT/IT1995/000068 patent/WO1995031085A1/en active IP Right Grant
- 1995-05-05 AU AU24183/95A patent/AU684024B2/en not_active Ceased
Non-Patent Citations (1)
Title |
---|
See references of WO9531085A1 * |
Also Published As
Publication number | Publication date |
---|---|
ES2110847T3 (en) | 1998-02-16 |
AU684024B2 (en) | 1997-11-27 |
EP0759263B1 (en) | 1997-11-19 |
IT1269728B (en) | 1997-04-15 |
DE69501083T2 (en) | 1998-03-12 |
WO1995031085A1 (en) | 1995-11-16 |
ITMI940908A0 (en) | 1994-05-09 |
ITMI940908A1 (en) | 1995-11-09 |
DE69501083D1 (en) | 1998-01-02 |
AU2418395A (en) | 1995-11-29 |
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