DE20107743U1 - Variably ventilated oven door - Google Patents

Description

BOEHMERT & BOEHMERT

LAW FIRM

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German Patent and Trademark Office Zweibrückenstr. 12

80297 Munich DR-ING. KARL [JOEIIMERT. PA tvm-vnsi
DIPL INC. ALOERTBOEHMERT, case ll'»:-l»ili
WILHELM JH STAHLBERG. R.A. IJrcra
DR.-ING. WALTER HOORMAKN. PA-. Brenen
DIPL. PIIYS. OR. HEINZ GODDAR, !V. Mim*«.
DR-ING. ROLAND LIESEGANG. PA-. Muicnen

WOLf-DIETER KUNTZE. Attorney. Bremen. Alieanle

DIPL-PHYS. ROBERTMÜNZHUBER, PA(TO-IWi

DR. LUDWIG KOUKER. Attorney, Kremen

DR. (CHEM.) ANDREAS W1NKLF.R. &Rgr;&Lgr;·. Listen,

MICHAELA HUTH-DIERIG. Lawyer Munich

DIPL.-PHYS. DR. MARION TÖNHARDT. ρλ·. DiLv^ldurf

DR. ANDREAS EBERT-WEIDENFELLER. R.A. Immense

DIPL.-ING. EVA LIESEGANG. &Rgr;&Lgr;·. Mutidwn

DR. AXEL NORDEMANN. RA, Uerin

DIPL.-PHYS. DR. DOROTHEE WEBER-BRULS. PA-. Frankfun

DIPL.-PHYS. DR. STEFAN SCHOHE, &Rgr;&Lgr;·. Munich

DR.-ING. MATTHIAS PHILIPP, PA-. Bielefeld

DR. MARTIN WIRTZ, RA. Dusseldorf

DR. DETMAR SCHÄFER. Attorney at law Bremen

DR. JAN BERND NORDEMAjNN, LL.M.. RA, Berlin

PA ■ Patent Attorney/Patent Anumey

RA - Reehlsanwiilt/Attorney ■( U*

* - Hungarian Patent Attorney

^&Lgr; - Brandenburg, zu£ela««n at the OLG Brandenburg

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PROH DR. WILHELM NORUEMANS. Rvnhi.' DIPL PHYS. EDUARD MAUMANN', :·.·,-. &pgr;,,&iacgr;,^. DR.-ING. GERALD KLOPSCII. .·.-■ I .;..«;j&rdquor;ri DIPL.-ING. IIA.N'S W. GROESIN ¹ G. µ·, '.&igr;.,&igr;&kgr;&iacgr;&kgr;,, UIPL.-ING. SIEGFRIED SCHIRMUR. ig>λ·. luA.e DIPL.-PHYS. LORENZ HANE'.VIN'KEL. PA·. I·:. DIPL-ING. DR. JAN TÖNNIES. Pa. K.'.. KkI DIPL.-PHYS. CHRISTIAN BII=HL. Pa-. Kiel DIPL.-PHYS. DR.-ING. L"A'E MANASSE. l-\"< DR. CHRISTIAN CZYCHOWSKI. KA. iienm DR- CARL-RICHARD HAARMANN. K.VM.mdw DIPL.-PHYS . DR. THOMAS L. BlTTNER. PA-. DR. VOLKER SCHMITZ, R.,. Müchm DIPL-PHYS. CHRISTIAN W. APPELT. ia-.m,, DR. ANKE NORDEMANN-SCHIFKEL. r.-\=".Ph KERSTIN MAUCH. LLM.. RA, &rgr;,,..»!«.-, DIPL-BIOL. DR. JAN B. KRAUSS. Pi Munich JÜRGEN ALBRECHT, ?_v .vowhen ANKE SIEBOLD . RA. Bremen DR. KLAUS TIM BRÖCKER. RA, Halm ANDREAS DUSTMANN, LL.M., XA. htJm, DIPL.-ING. NILS TF SCHM ID, P,\ Munich

In collaboration with'in ei^ipenilutn with

DIPL-CHEM. DR. HANS ULRICH MAY. PA-.

Your sign
Your ref.

Your letter of

New registration (utility model) Our symbol
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L50046

Bremen,

07 May 2001

Rational AG

Iglinger Strasse 62

86899 Landsberg am Lech

Variable ventilated cooking chamber door

Description

The invention relates to a cooking chamber door for a cooking appliance, with two individual panes, in particular in the form of single-pane safety glass and/or laminated glass, and an intermediate space running between them, which is partially, in particular on its vertical sides, connected by connections between the individual panes, which determine the distance between the

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MUNICH ■ BREMEN BERLIN DÜSBELftORF - FRAN&FUfW B&LEf-tLD -&Igr;&rgr;&Ogr;&Idigr;5&Ogr;.&Igr;&Mgr; - BRjJNDE^^RC - KjEL - ijADJRBOJ<.N· - HÖHENKIRCHEN - ALICANTE

http://www.boehmert.de e-mail: postmaster@boehmert.c]e

BOEHMERT & BOEHMERT -2-

Define individual panes, closed and in some areas, particularly on the horizontal sides, at least temporarily open for at least one air flow channel through the space between them.

In general, insulating glass is well known. It basically consists of at least two individual panes of glass that are connected to one another in such a way that a sealed gap remains between these individual panes of glass, which is filled with air and/or an inert gas and, if necessary, additives. Insulating glass is also used in the cooking appliance industry to reduce heat emission from the cooking chamber. However, the disadvantage of cooking chamber insulating glass doors is that, despite the insulating effect of the air or inert gas in the gap between the individual panes of glass, the outer individual pane of glass facing away from the cooking chamber heats up, which sometimes leads to very high temperatures on the surface of this outer individual pane of glass and thus represents an increased risk of injury for the user. Even the interposition of a heat shield, as disclosed in US 3,877,460, for example, cannot prevent the outer individual pane of glass from overheating.

In order to prevent the individual pane of glass facing away from the cooking chamber from heating up too much, cooking chamber doors for cooking appliances are known from the prior art, in which an additional individual pane of glass is arranged in front of an insulating glass arrangement on the side facing away from the cooking chamber, which then forms the outer pane of the cooking chamber door. For example, a door cooling system is known from US 3,889,099, which is used in an oven. The cooking chamber of the oven is surrounded by a second housing in such a way that channels are formed between the outer wall of the cooking chamber and the housing of the oven. Air flows through these channels for cooling purposes, which is driven by a fan. In addition, the oven comprises a front which consists of two panels, whereby the panel facing the cooking chamber contains a window in the form of an insulating glass arrangement, while the other panel contains a window consisting of an individual pane of glass. The panel facing away from the cooking chamber forms a frame by means of bends on its edge.

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BOEHMERT & BOEHMERT

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the front door. This frame is designed in such a way that there are openings at the horizontal ends of the frame so that air can flow horizontally between the two panels through the front door to cool the individual panes of glass. The air outlet openings of a channel formed between the top of the cooking chamber and the top of the oven housing are designed in such a way that a negative pressure is created on the top of the frame of the front door, thus forcing the flow of air through the front door.

The arrangement of an additional third single pane of glass in front of an insulating glass arrangement consisting of two single panes of glass that are connected to one another via a closed frame, with air flowing through a channel between the single pane of glass and the insulating glass arrangement to cool the single pane of glass, is also known from FR 2.113.196. Within the insulating glass arrangement, slats are arranged in a vertical direction and can be rotated via a temperature-controlled mechanism, thus forming a blind within the space between them. If this insulating glass arrangement is installed in the cooking chamber insulating glass door of an oven, the slats are rotated during normal operation of the oven so that a user can look into the interior of the oven through this insulating glass arrangement. If the temperature in the oven exceeds a predetermined value, in particular during a cleaning process, the slats are rotated by a mechanism so that the blind is closed. The slats then act as a heat shield and thus reduce the heating of the single pane of glass facing away from the cooking chamber. The third single pane of glass is arranged in front of the insulating glass arrangement in such a way that a channel is formed through which air can flow for cooling.

However, this design of a cooking chamber door has the disadvantage that if the previously determined temperature is exceeded, the blind is closed and it is no longer possible to look into the cooking chamber. In addition, the blind only partially prevents the outer pane of the insulating glass assembly from heating up excessively, since the blind only prevents the pane from heating up by heat radiation from one side to the other.

BOEHMERT & BOEHMERT

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pane is prevented, while heating by convection within the gap is not prevented.

In the oven of DE 40 28 674 A1, an oven door is provided which comprises a double pane facing the oven muffle and an outer door pane, between which an air flow rate which varies across the width of the door is provided for uniform cooling of the outer door pane.

The disadvantage of cooking chamber doors in which an additional single pane of glass is arranged in front of an insulating glass arrangement, with air flowing through the space between this single pane of glass and the insulating glass arrangement, is that the additional single pane of glass makes the cooking chamber door heavier, has a greater thickness and requires a more complex construction.

DE 42 40 096 A1 discloses a pressure equalization device for spaces containing gaseous media, in particular for the space between multiple panes of glass that are exposed to temperature fluctuations, in the form of at least one filter element.

US 3,489,135 discloses an oven door which consists of a main frame into which a first glass pane is inserted on the side facing the oven and to which a second frame is connected via hinges on the side facing away from the oven, into which a protective glass pane is inserted. This construction enables the cleaning of the opposite sides of the glass panes in the space between the glass panes. The two frames are dimensioned in such a way that air can get into the space between the glass panes through gaps between the two frames and the protective glass pane is cooled by this air flow. In order to prevent excessive cooling of the glass pane facing the oven, a special dimensioning of the gap is proposed.

BOEHMERT & BOEHMERT
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From US 3,186,401 a generic cooking chamber door for a cooking oven is known, which comprises two parallel glass panes. The housing of the cooking oven is designed, similar to the oven known from US 3,889,099, in such a way that the cooking chamber is separated from the outer walls of the cooking oven and channels are formed through which by means of a
The oven's cooking chamber door is designed so that the vertical edges of the cooking chamber insulating glass door are closed, while the horizontal edges have openings that allow air to flow through the space between the two panes of glass. To this end, the opening at the bottom of the cooking chamber insulating glass door is aligned with a channel that separates the cooking chamber from the front of the oven. Air therefore flows directly from this channel through the space between the panes and exits at the top of the cooking chamber insulating glass door, and a cooling effect is achieved by the air flowing through.

However, a disadvantage of the ventilated cooking chamber doors disclosed in the last two publications mentioned is that the air flowing through cools not only the individual glass pane facing away from the oven, but also the individual glass pane facing the oven, which leads to a removal of heat from the cooking oven and thus to an increased energy loss.

The object of the present invention is therefore to provide the generic cooking chamber door in such a way
to further develop such that the disadvantages of the prior art are overcome, in particular to provide a cooking chamber door in which the surface temperature of the individual glass pane facing away from a cooking chamber does not exceed a predetermined temperature value in order to minimize the risk of injury and at the same time energy losses are minimized, while the cooking chamber door is nevertheless light and has a small thickness.

This object is achieved according to the invention in that the at least one air flow channel can be opened or closed by a user and/or automatically, in particular during a cooking process and/or cleaning process.

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An advantageous embodiment of a cooking chamber door is characterized by at least one closure device, preferably at least two coupled closure devices, via which openings, in particular on the horizontal sides of the intermediate space, can be closed to insulate the intermediate space or are at least partially open for a certain period of time, in particular for cooling the second individual pane facing away from the cooking chamber by means of the air flow through the air flow channel.

It can be provided that each closure device is controllable and/or adjustable depending on the air temperature in the intermediate space and/or the surface temperature of the second individual pane.

It is further proposed that a cooking chamber door according to the invention is characterized by a control and/or regulating unit, preferably in the intermediate space, which controls and/or regulates the closure devices by means of a temperature-dependent change in shape of a bimetal and/or a wax element and/or the temperature-dependent expansion of a liquid and/or a motor.

According to the invention, it is preferred that the first and/or second individual pane has or have a heat-reflecting coating on the side facing the cooking chamber.

It can be provided that a cooking chamber door according to the invention is characterized by a, preferably partially transparent, heat protection shield for reducing the heating of the second individual pane, in particular between the locking devices.

It can also be provided that the air flowing through the at least one air flow channel can be driven by thermals and/or a fan that can be adjusted via the control and/or regulating unit.

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The invention also proposes that the connections between the individual panes are designed to be at least partially separable, wherein the connections on one, in particular vertical, side of the intermediate space between the individual panes are preferably separable by means of at least one locking mechanism and on the other side of the intermediate space opposite the one side are designed with a pivot point for pivoting the individual panes against each other.

Furthermore, the invention proposes that the closure devices comprise flaps and/or two plates which can be displaced relative to one another and have congruent openings, a first of which is firmly connected to the individual panes and the second of which is displaceable relative to the first plate, wherein the openings preferably have, at least in part, different sizes.

Finally, an embodiment according to the invention is characterized by an input unit, a display unit, at least one sensor and/or lighting, in particular in operative connection with the control and/or regulating unit.

Further features and advantages of the invention emerge from the following description, in which preferred embodiments of the invention are explained in detail using schematic drawings.

Figure 1 is a longitudinal sectional view of a cooking chamber door according to the invention in a cooking appliance, in the ventilated state;

Figure 2 is a longitudinal sectional view of the cooking chamber door of Figure 1, in the sealed state;

Figure 3 is a cross-sectional view through another cooking chamber door according to the invention, in

sealed condition;

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Fig. 4 a view like Figure 3, with the outer pane open; and

Figure 5 shows a detail of a longitudinal sectional view of a further advantageous embodiment of the cooking chamber door according to the invention.

Figure 1 shows a cooking chamber door 100 according to the invention in longitudinal section, which comprises two individual panes 1 and 3 arranged parallel to one another, for example in the form of safety glass, which are separated from one another by an intermediate space 5. The individual panes 1 and 3 are fastened in a door frame formed by connections 7, which in turn is connected to a cooking appliance housing 11 via swivel joints 9. The cooking appliance housing 11, together with the cooking chamber door 100, encloses a cooking chamber 13, wherein a mechanism (not shown) for opening and closing the cooking chamber door 100 is present.

The inner single pane 1 faces the cooking chamber 13. In this embodiment, two closure devices 15a and 15b in the form of flaps, which are rotatably mounted via hinges 17a and 17b, are arranged in the intermediate space 5. These two closure devices 15a and 15b are mechanically connected to one another via a connecting member, here in the form of a connecting rod 19a. This connecting rod 19a is connected to a control unit 23 via a lever 21. This control unit 23 comprises a bimetal (not shown) which is in thermal contact with the outer single pane 3.

In the state shown in Figure 1, the outer single pane 3 is at a temperature that is higher than a predetermined value, so that the lever 21 is deflected upwards in the direction of the outer single pane 3 by a deformation of the bimetal 5 and the two locking devices 15a and 15b are in the open position due to the mechanical connection with the lever 21 via the connecting rod 19a. The door frame is designed in such a way that the vertical sides are closed, while the connecting

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ings 7 have openings (not shown) on the horizontal sides. The intermediate space 5 thus represents a tCanal through which air can flow along the arrows shown in Figure 1. Although the thermals are basically sufficient to drive such an air flow, in an advantageous embodiment the air flow is additionally driven by a fan (not shown) which is connected to the control unit 23. Due to the air flow, the outer single pane 3 cools down.

Due to this cooling, the temperature of the outer single pane 3 decreases. Since the control unit 23 is thermally coupled to the outer single pane 3, the temperature of the bimetal in the control unit 23 also decreases until the bimetal deforms again and the lever 21 returns to its lower position in the direction of the inner single pane 1 due to the deformation of the bimetal. Since the lever 21 is mechanically connected to the locking devices 15a and 15b via the connecting rod 19a, in this operating state the openings on the horizontal sides of the door frame are closed via the locking devices 15a and 15b. The air flow through the gap 5 is thus prevented. At the same time, the fan is switched off via the control unit 23. In this state, the cooking chamber door 100 represents an insulating glass arrangement, since the intermediate space 5 is closed by the closed vertical sides of the door frame and the locking devices 15a and 15b. This state is shown in Figure 2.

Due to the heat in the cooking chamber 13, the inner single pane 1 heats up, while the outer single pane 3 is thermally insulated from the cooking chamber 13 to reduce the heat emission. In order to further reduce the heat emission, in further advantageous embodiments at least one single pane 1 and/or 3 can be coated with a heat-reflecting coating on its side facing the cooking chamber 13 and/or an at least partially transparent heat protection shield 31 can be attached between two connecting rods 19a and 19b, as shown in Figure 3. However, it is not possible to completely prevent the heat transfer from the inner single pane 1 to the outer single pane 3. If the outer single pane 3 were to continue to heat up, the surface

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temperature, this individual pane 3 could reach a level that would pose a danger to a user. Therefore, the control unit 23 uses the lever 21 and the connecting rod(s) 19a (and 19b) to move the locking devices 15a and 15b into the position shown in Figure 1 in order to allow an air flow through the intermediate space 5 and thus cooling of the individual pane 3.

Figure 3 shows a cross section through another cooking chamber door 100 according to the invention. In Figure 3, the locking devices 15a, 15b, of which only one (15a) can be seen, are in the closed state, and the two connecting rods 19a and 19b can be seen, between which the heat protection shield 31 is attached. On the left side of Figure 3, the pivot point 27, around which the cooking chamber door 100 is connected to the cooking appliance housing via the pivot joint 9, is shown. According to the advantageous embodiment of the cooking chamber door 100 shown in Figure 3, the connections 7 are divided into two parts. On the left side, the two parts of the connections 7 are connected via hinges (not shown) at the pivot point 27, while on the opposite right side they can be connected to one another via a locking mechanism 29. Due to the air flow through the intermediate space 5, the surfaces of the individual panes 1 and 3 on the sides facing the intermediate space 5 can become contaminated. In order to enable cleaning of these surfaces and easy access to the intermediate space 5, the locking devices 15a and 15b, the connecting rods 19a and 19b, the lever 21 and the control unit 23, the connection of the two connections 7 can be opened via the locking mechanism 29.

Since the two connections 7 are movably mounted via the hinges in the pivot point 27, the cooking chamber door 100 can be opened in the manner shown in Figure 4. The distance between the individual panes 1 and 3 is defined by the dimensioning of the connections 7. An elastic insulation 25 ensures sufficient insulation of the space between the panes 5 on the vertical sides when the cooking chamber door 100 is closed.

BOEHMERT & BOEHMERT

Figure 5 shows a detail of a longitudinal section of a further advantageous embodiment of the cooking chamber door 100 according to the invention. In this embodiment, the locking device 15a, which is connected to the second locking device (not shown) via the connecting rod 19a, is moved by a motor 35 in the form of a stepper motor. This motor 35 is connected to a control unit which is located in the housing of the motor 35. This control unit is in turn connected to a temperature sensor 33 which is in thermal contact with the surface of the outer single pane 3 facing away from the cooking chamber. If the surface temperature of the single pane 3 reaches a predetermined value, the locking device 15a is opened by means of the motor 35. Since this is connected to the locking device located at the lower end of the cooking chamber door via the connecting rod 19a, when the locking device 15a is open, an air flow occurs through the intermediate space 5, which leads to cooling of the outer single pane 3. If the surface temperature of the outer single pane 3 falls below a certain value, the locking devices 15a are closed by means of the motor 35 and the intermediate space 5 is insulated. As already mentioned, in this operating state the heat emission from the cooking chamber 13 to the outer single pane 3 is greatly reduced.

Thus, according to the invention, a cooking chamber door for a cooking appliance is provided in a simple manner which ensures low heat emission from the cooking chamber and at the same time prevents the surface temperature of an individual pane facing away from the cooking chamber from exceeding a critical value.

The features of the invention disclosed in the above description, in the drawings and in the claims may be essential for the realization of the invention in its various embodiments both individually and in any combination.

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List of reference symbols

1 Single pane 3 Single pane 5 Space 7 links 9 Swivel joint &Pgr; Cooking appliance housing 13 Cooking chamber 15a, 15b Locking device 17a, 17b hinge 19a, 19b Connecting rod 21 lever 23 Control unit 25 Elastic insulation 27 pivot point 29 Locking mechanism 31 Heat shield 33 Temperature sensor 35 engine 100 Cooking chamber door

Claims (10)

1. Cooking chamber door for a cooking appliance, with two individual panes, in particular in the form of single-pane safety glass and/or laminated glass, and an intermediate space running therebetween, which is closed in some areas, in particular on its vertical sides, by connections between the individual panes which define the distance between the individual panes, and is open in some areas, in particular on the horizontal sides, at least temporarily for at least one air flow channel through the intermediate space, characterized in that the at least one air flow channel can be opened or closed by a user and/or automatically, in particular during a cooking process and/or cleaning process. 2. Cooking chamber door according to claim 1, characterized by at least one closure device ( 15 a, 15 b), preferably at least two coupled closure devices ( 15 a, 15 b), via which openings, in particular on the horizontal sides of the intermediate space ( 5 ), can be closed to insulate the intermediate space ( 5 ) or can be opened, at least partially, for a certain period of time, in particular for cooling the second individual pane ( 3 ) facing away from the cooking chamber ( 13 ) by means of the air flow through the air flow channel. 3. Cooking chamber door according to claim 1 or 2, characterized in that each closure device ( 15a , 15b ) is controllable and/or adjustable depending on the air temperature in the intermediate space ( 5 ) and/or the surface temperature of the second individual pane ( 3 ). 4. Cooking chamber door according to one of the preceding claims, characterized by a control and/or regulating unit ( 23 ), preferably in the intermediate space ( 5 ), which controls and/or regulates the closure devices ( 15a , 15b ) by means of a temperature-dependent change in shape of a bimetal and/or a wax element and/or the temperature-dependent expansion of a liquid and/or a motor ( 35 ). 5. Cooking chamber door according to one of the preceding claims, characterized in that the first and/or second individual pane ( 1 , 3 ) has or have a heat-reflecting coating on the side facing the cooking chamber ( 13 ). 6. Cooking chamber door according to one of the preceding claims, characterized by a, preferably partially transparent, heat protection shield ( 31 ) for reducing the heating of the second individual pane ( 3 ), in particular between the locking devices ( 15a , 15b ). 7. Cooking chamber door according to one of the preceding claims, characterized in that the air flowing through the at least one air flow channel can be driven by thermals and/or a fan adjustable via the control and/or regulating unit ( 23 ). 8. Cooking chamber door according to one of the preceding claims, characterized in that the connections ( 7 ) between the individual panes ( 1 , 3 ) are designed to be at least partially separable, wherein preferably the connections ( 7 ) on one, in particular vertical, side of the intermediate space ( 5 ) between the individual panes ( 1 , 3 ) are separable by means of at least one locking mechanism ( 29 ) and on the other side of the intermediate space ( 5 ) opposite the one side are designed with a pivot point ( 27 ) for pivoting the individual panes ( 1 , 3 ) against each other. 9. Cooking chamber door according to one of the preceding claims, characterized in that the closure devices ( 15 a, 15 b) comprise flaps and/or two plates which can be displaced relative to one another and have congruent openings, a first of which is firmly connected to the individual panes ( 1 , 3 ) and the second of which is displaceable relative to the first plate, wherein the openings preferably have, at least in part, different sizes. 10. Cooking chamber door according to one of the preceding claims, characterized by an input unit, a display unit, at least one sensor and/or lighting, in particular in operative connection with the control and/or regulating unit ( 23 ).