U.S. patent application number 10/955751 was filed with the patent office on 2005-05-26 for energy-saving cooking appliance door having a low front temperature.
This patent application is currently assigned to BSH Bosch und Siemens. Invention is credited to Beck, Andreas, Drach, Volker, Ebert, Hans-Peter.
Application Number | 20050109335 10/955751 |
Document ID | / |
Family ID | 29285107 |
Filed Date | 2005-05-26 |
United States Patent
Application |
20050109335 |
Kind Code |
A1 |
Beck, Andreas ; et
al. |
May 26, 2005 |
Energy-saving cooking appliance door having a low front
temperature
Abstract
A cooking appliance door having an inner and an outer wall and a
perforated wall therebetween. Air flows through the door and the
perforated wall, which can be substantially all or a portion of the
perforated wall.
Inventors: |
Beck, Andreas;
(Waldbuttelbrunn, DE) ; Drach, Volker;
(Waldbuttelbrunn, DE) ; Ebert, Hans-Peter;
(Dettelbach, DE) |
Correspondence
Address: |
JOHN T. WINBURN
100 BOSCH BOULEVARD
NEW BERN
NC
28562
US
|
Assignee: |
BSH Bosch und Siemens
Munich
DE
|
Family ID: |
29285107 |
Appl. No.: |
10/955751 |
Filed: |
September 30, 2004 |
Current U.S.
Class: |
126/198 ;
126/200 |
Current CPC
Class: |
F24C 15/04 20130101;
F24C 15/006 20130101 |
Class at
Publication: |
126/198 ;
126/200 |
International
Class: |
F24C 015/04 |
Foreign Application Data
Date |
Code |
Application Number |
May 6, 2003 |
WO |
PCT/EP03/04756 |
May 6, 2002 |
DE |
DE 10220133.1 |
Claims
1-9. (canceled)
10. A cooking appliance door, comprising: an inner wall; an outer
wall; and an intermediate wall arranged between said inner wall and
said outer wall, said intermediate wall including at least a
perforated wall portion through which air flows.
11. The cooking appliance door according to claim 10, including
said air enters the door at a front side of said door.
12. The cooking appliance door according to claim 10, wherein said
door includes a transparent surface area and said perforated wall
portion is provided only in said transparent surface area.
13. The cooking appliance door according to claim 10, including
said perforated wall portion is formed from a glass pane.
14. The cooking appliance door according to claim 10, including
said perforated wall portion includes holes or slots with a typical
hole diameter or a slot width substantially on the order of 100
.mu.m to 1 cm.
15. The cooking appliance door according to claim 10, including the
surface of said perforated wall portion is provided on at least one
side with an infrared-reflecting coating.
16. The cooking appliance door according to claim 10, including
said air is warmed as it flows through the door and said warmed air
guided through said perforated wall portion is deflected outwards
to the atmosphere.
17. The cooking appliance door according to claim 10, including
said air is forced to flowthrough said perforated wall portion by a
ventilator system present in the cooking appliance.
18. The cooking appliance door according to claim 10, including the
surface portion of said perforated wall portion is substantially on
the order of between about 0.1% and 50%.
Description
[0001] The invention relates to a cooking appliance door as claimed
in the preamble of claim 1.
[0002] Cooking appliance doors ought to fulfil a number of
requirements simultaneously: viewing of the cooked goods, minimal
heat loss and minimal front temperatures while the system thickness
of the baking oven door construction remains as minimal as
possible. In particular in the case of cooking appliances with
pyrolytic self-cleaning at inner temperatures of 500.degree. C.
there is increased requirement for heat insulating effect of the
cooking appliance doors. On account of their multifunctional tasks
cooking appliance doors can also be thermal weak spots in cooking
appliance construction.
[0003] A cooking appliance door is known from U.S. Pat. No.
4,084,571, whereby a heat shield is provided between the multipart
and rear part designed as trough-shaped door base and the front
part designed as front frame with inset pane in the region of a
pane packet mounted on the door base between the pane packet or the
door base and the front frame or the front glass pane. The heat
shield has countless openings for improving the view in and is
highly reflective on the side facing the cooking chamber. On the
side facing away from the cooking chamber the heat shield is
blackened.
[0004] DE 43 04 485 A1 also discloses a baking oven door, whereby
the metallic door encloses a pane facing the baking oven muffle.
Attached to the door base is a front pane. In the region opposite
the metallic door floor the mounted front glass pane is partially
provided on its inner side facing the cooking chamber with a
reflective layer, for example with surface-polished aluminium
foil.
[0005] EP 1039 2323 A2 discloses a cooking appliance door, wherein
a thermal functional part is arranged at a distance from the front
part between the front part, to which a door handle is assigned,
and a back part. The functional part can be a multilayer insulation
film, in particular aluminium, which has integrated air
chambers.
[0006] A baking oven according to the document U.S. Pat. No.
4,084,571 has a square metallic oven muffle open to the front. This
is substantially insulated thermally on all sides in a manner known
per se. Heating elements known per se for heating the cooking
chamber are also arranged in the oven muffle. The oven muffle can
be sealed at the front by an oven door. In general the baking oven
door has a window system.
[0007] This comprises a mounted pane packet, comprising 2 to 4
generally partially infrared-reflected panes or an additional
perforated heat shield (U.S. Pat. No. 4,084,571).
[0008] The object of the present invention is to lower the front
temperatures in a cooking appliance door.
[0009] According to the invention this is achieved by a perforated
wall through which air flows being arranged between the inner wall
and the outer wall of the door. In a cooking appliance door with an
additional perforated partition between hot and cool side and air
guiding through this perforation lower front temperatures are
achieved and heat loss flows through the door construction are
clearly decreased.
[0010] Further advantageous embodiments are to be inferred from the
independent claims.
[0011] In the sole diagrammatic figure a baking oven with a door
designed according to the present invention is shown in section. A
baking oven known per se has an oven muffle 1, in which focused
heating can be applied by way of heating elements--not shown
here--and control and operating and display elements of the cooking
chamber. The cooking chamber is sealed by the door, which has a
front-side outer wall 3, a cooking chamber-side inner wall 5 as
well as an intermediate wall 7 arranged therebetween. The door is
held together by different fastening and/or mounting elements at
the discretion of the expert, while the outer wall 3 and the inner
wall 5 comprise glass or glasslike material.
[0012] The perforated intermediate wall 7 is arranged between the
outer and inner wall 3, 5 of the door, such that forced air flow
through the perforated wall 7 is achieved. The air 7 is suctioned
at a lower door edge into the door interior and suctioned at an
upper door edge from the door interior. Because of the flowthrough
of the perforated wall the thickness of the thermal limiting layer,
which has a raised temperature as gas layer near the surface, is
substantially reduced and thus the heat transport is diminished by
the adjacent gas cavity to the outer pane 3; ideally, the region
between the thermal limiting layer and the outer pane 3 has the
temperature of the suctioned air. At the same time the perforated
wall 7 through which air has flowed is cooled by the forced
convection. The cooling leads to lower surface temperatures in the
perforated wall, resulting in reduced heat radiation exchange with
the opposite outer wall surface 3.
[0013] In summary, the perforation through which air flows has the
following advantages:
[0014] The usual convection roller between two walls is hindered by
the inventive measure. The air heated on the perforated
intermediate wall 7 is aspirated and does not make thermal contact
with the cooler outer wall 3. The perforations, or the air ducts
promote good thermal coupling of the wall with the air and thus
efficient heat energy removal from the intermediate wall 7 to the
suctioned air. Cooling the perforated wall lowers its radiation
emission, resulting in lower heat radiation losses.
[0015] For further reduction of the heat radiation exchange the
intermediate wall 7 can be provided with a low-emitting layer (not
shown) if required. Thus the surface temperatures of the outside of
the baking oven doors are significantly reduced.
[0016] The system shows the best results when suctioning of the
cooler air takes place in an outer cavity of the door system--also
front side--and the aspiration of the heated air takes place in an
inner cavity of the door system. The direction of flow of the air
flowing through the door is also against the direction of the heat
loss through the door.
[0017] The perforated wall 7 can have an opening 9 either only in a
transparent region of the door or over the entire surface of the
cooking appliance door. The position of the perforated wall inside
the wall structure of the cooking appliance door or pane packet of
the cooking appliance door is not decisive for the physical effect.
At least the cavities in front of and behind the perforated wall 7
are to be provided for the air guiding. The suctioned air is taken
from the environment outside the cooking appliance and after being
heated is again discharged to the exterior on the perforated wall.
According to the figure to this end the baking oven has a cooling
fan 11, which blows cool air over a frontal open outlet shaft 13
from the baking oven. Through the injector effect as a result of
suitable narrowing of the flow channel formed by the discharge
shaft 13 air is drawn from the door in a manner known per se.
[0018] Alternatively, it can also be provided that the cool air
flowing through the intermediate wall 7 flows back at will into the
cooking chamber as a result of subpressure building up in the
cooking chamber. For this if can for example be provided that a
fumes fan and/or the cooling fan 11 draws fumes out of the cooking
chamber via a opening (not shown) of the muffle 1. The prerequisite
for this however is a flow-technical connection between the door
and the cooking chamber. In the event of introducing the heated air
into the cooking chamber energy savings is possible by using the
pre-heated air; the heat loss occurring with conventional cooking
appliance doors is reduced and part of the energy can be recycled
to the cooking appliance.
[0019] The perforated wall 7 is understood to be a perforated glass
pane, a perforated plastic pane, a perforated film or a perforated
sheet etc. The perforation comprises the holes 9 or slots with a
typical hole diameter or gap width of 100 .mu.m to 1 cm. The
surface portion of the perforation on the wall can vary from ca.
0.1% to 50%.
[0020] In summary the forced flowthrough of the perforated wall can
be accomplished by a ventilator system placed in the cooking
appliance (e.g. range hood), or a ventilator system e.g. integrated
in the cooking appliance door. If required, a flowthrough of the
perforated film can be created indirectly by available air flow,
e.g. through the range hood flowing outwards over the upper edge of
the cooking appliance door utilising the Venturi effect. To avoid
contamination of the perforated wall the suctioned air can be
cleaned in advance by an appropriate filter system.
* * * * *