EP1657494A1

EP1657494A1 - Exhaust hood

Info

Publication number: EP1657494A1
Application number: EP05005889A
Authority: EP
Inventors: Seung Jo Baek; Sung Bae Song; Sang Bum Sohn; Je Jun Lee
Original assignee: LG Electronics Inc
Current assignee: LG Electronics Inc
Priority date: 2004-11-10
Filing date: 2005-03-17
Publication date: 2006-05-17
Anticipated expiration: 2025-03-17
Also published as: AU2005201104B2; AU2005201104A1; CN1773174B; EP1657494B1; KR20060042687A; CN1773174A; KR100644837B1

Abstract

An exhaust hood is disclosed. The exhaust hood includes a body (12) having an exhaust fan (16) disposed at the upper side of a food preparation area and exhausting indoor air, and a filter (14) disposed at an inlet (12a) through which the indoor air is sucked and filtering the indoor air, a wall jet generator (20) for injecting air so as to generate a wall jet flowing along the curved surface at the front side of the body (12), and an air stream guide (30) disposed a predetermined distance from the curved surface and guiding the air stream generated by the wall jet flowing to the inlet (12a), so that the polluted air generated in the food preparation area in the kitchen is effectively collected.

Description

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to an exhaust hood, and more particularly, to an exhaust hood including an air stream guide for effectively connecting an air stream formed by the wall jet generated in front of the exhaust hood without separation of the air stream so as to enhance collection efficiency of polluted air generated from the food preparation area in the kitchen.

Description of the Related Art

Generally, there are food preparation areas, in the kitchen, where heating devices such as electric heaters, gas ranges, and the like for cooking food by supplying heat so as to heat or roast food are placed.
Cooking most food generates odors due to the high temperatures caused by the heating device in food preparation area, these odors may take the form of oil particles or other various aerosols which are dispersed in the air within the kitchen and thus stimulate the sense of smell of persons present thereabouts. These odors are generally considered to be unpleasant to the senses and, additionally, decrease ones concentration and have negative health effects.
Fig. 1 is a schematic view illustrating a conventional kitchen exhaust hood.
The conventional kitchen exhaust hood, as shown in Fig. 1, is spaced apart from the food preparation area 7 for cooking food so as to form a cooking space, and has a side fixed on a mounting wall 8 and a top fixed to the ceiling 9.
The conventional exhaust hood includes body 2 forming the outward appearance of the conventional exhaust hood, a motor (not shown) for generating driving power for sucking air into the body 2 and exhausting the air to the exterior, an exhaust fan 6 electrically connected to the motor and sucking the air, a filter 4, disposed at the bottom of the body 2, through which the air passes while being sucked into the body 2, and a pipe (not shown) serving as a passage through which the air passed through the filter 4 and sucked into the body 2 is exhausted to the exterior.
The conventional exhaust hood is operated as follows.
Polluted air containing gas, grease droplets, and the like generated during cooking ascend because of their own buoyancy due to temperature higher than the ambient air or compulsorily ascend by the exhaust fan 6, and the ascended polluted air passes through the filter 4 and is exhausted to the exterior through the external duct.
However, since the conventional exhaust hood for exhausting the polluted air using the exhaust fan sucks air, near to an inlet disposed at the bottom of the body of the exhaust hood, but suction power of the conventional exhaust hood with respect to air far from the inlet is weakened in proportion to the inverse square of the distance, and even if the exhaust fan has large suction power, the collecting efficiency of the conventional exhaust hood is not directly proportional to the suction power when distance between the food preparation area where the polluted air is generated and the inlet is long.
In addition, since most cooking is performed in front of the food preparation area 7, the polluted air ascends toward the outer space of the body 2 even when the exhaust fan 6 operates, collides with the lower surface of the body 2, or escapes from the dust collecting space of the conventional exhaust hood.
Further, the amount of the polluted air which is not collected by the conventional exhaust hood is increased when the exhaust fan 6 generates an air stream with slower than a polluted air stream with desired flow rate, and the flow rate of the polluted air substantially sucked through the inlet is reduced by the resistance of the filter 4. Even when the exhaust fan 6 generates the desired flow rate to suck the polluted air, the polluted air cannot be effectively collected into the conventional exhaust hood and pollutes the kitchen.

SUMMARY OF THE INVENTION

Therefore, the present invention has been made in view of the above and/or other problems, and it is an object of the present invention to provide an exhaust hood for effectively collecting the polluted air generated from the food preparation area in the kitchen using a small amount of exhaust air so as to prevent the polluted air from spreading throughout the kitchen and other rooms.
In accordance with the present invention, the above and other aspects can be accomplished by the provision of an exhaust hood including a body including an exhaust fan disposed at the upper side of a food preparation area and exhausting indoor air, and a filter disposed at an inlet through which the indoor air is sucked and filtering the sucked indoor air, a wall jet generator for generating wall jet flowing along the curved surface at the front side of the body by injecting air, and an air stream guide disposed a predetermined distance from the curved surface and guiding the air stream generated by the wall jet flowing to the filter inlet.
Preferably, the air stream guide is disposed at the position where the air stream is generated by the wall jet.
The curved surface formed at the front side of the body is the outer circumference of a hollow cylindrical rod.
Moreover, the air stream guide is constructed such that the position where the air stream guide starts is the position where an angle from the position where the wall jet is generated on the hollow cylindrical rod is 80 degrees to 100 degrees in the direction that the air stream is formed, and the position where the air stream guide ends is where an angle from the position where the air stream guide starts is 20 degrees to 40 degrees.
The wall jet generator is constructed such that the position where the wall jet is generated on the hollow cylindrical rod is 80 degrees to 100 degrees from a plane parallel to the filter inlet.
In addition, the hollow cylindrical rod further includes an illuminating device.
Preferably, the wall jet generator maintains the velocity of the air stream guided by the air stream guide within the range of 3 m/s to 5 m/s.
Moreover, the air stream guide is constructed such that an upper gap between the air stream guide and the curved surface where the generated wall jet is introduced is wider than a lower gap between the air stream guide and the curved surface where the wall jet passes.
Preferably, the air stream guide is constructed such that the upper gap between the air stream guide and the curved surface is about 8 mm, and the lower gap between the air stream guide and the curved surface is about 6 mm.
According to the present invention, the wall jet generator injects the outside air of the body, or injects the air introduced into the body.
In addition, the body further includes a slit formed at the lower side of the body, through which the wall jet, after passing through the air stream guide, is directly introduced into the body.
As described above, the exhaust hood according to the present invention is capable of exhausting the polluted air near to the inlet of the body of the exhaust hood using the conventional exhaust fan effectively. Since the exhaust hood according to the present invention further includes the wall jet generator and the air stream guide for preventing the separation of the wall jet generated by the wall jet generator in order to collect the polluted air spaced apart from the inlet of the body and ineffectively collected by the conventional exhaust hood, the polluted air can be effectively collected without increasing the capacity of the exhaust fan.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects and advantages of the present invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings, in which:

Fig. 1 is a schematic view illustrating a conventional kitchen exhaust hood;
Fig. 2 is a sectional view illustrating an exhaust hood according to the first embodiment of the present invention;
Fig. 3 depicts streamlines generated around the front side of the exhaust hood according to the first embodiment of the present invention and streamlines generated around the front side of an exhaust hood without an air stream guide, for the purpose of comparison;
Fig. 4 is a sectional view illustrating an exhaust hood according to the second embodiment of the present invention; and
Fig. 5 is a sectional view illustrating an exhaust hood according to the third embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, the preferred embodiments of the exhaust hood according to the present invention will be described in detail with reference to the accompanying drawings.
Fig. 2 is a sectional view illustrating the exhaust hood according to the first embodiment of the present invention.
The exhaust hood according to the first embodiment of the present invention, as shown in Fig. 2, includes a body 12 having a curved front side and an inlet 12a formed at the bottom, a motor (not shown) for generating driving power for sucking air into the body 12 and exhausting the air to the exterior, an exhaust fan 16 electrically connected to the motor and sucking the air into the inlet 12a, a filter 14, disposed at the inlet 12a of the body 12, through which the air passes while being sucked into the body 12, and a pipe (not shown) serving as a passage through which the air, after passing through the filter 14 and being sucked into the body 12, is exhausted to the exterior, a wall jet generator 20 provided in the body 12 and injecting air to generate wall jet at a curved front of the body 12, and an air stream guide 30 provided where the wall jet generated by the wall jet generator 20 is separated and guiding an air stream toward the inlet 12a.
The wall jet generator 20 includes a wall jet fan motor 24 for flowing air flow by force so as to generate the wall jet, a discharge pipe 26 serving as a passageway through which the air flows toward the front side of the body 12 by the wall jet fan motor 24, a hollow cylindrical rod 28 horizontally disposed to the front lower corner of the body 12, and an injection nozzle 22 provided at the end of the discharge pipe 26 and injecting air flow generated by the wall jet fan motor 24 so as to generate the wall jet.
The lower side of the body 12 has a circular surface formed by the outer circumference of the hollow cylindrical rod 28, and the hollow cylindrical rod 28 is further provided with an illuminating device 29 therein.
Thus, the hollow cylindrical rod 28 is preferably made of transparent synthetic resin so that light emitted from the illuminating device 29 passes through the hollow cylindrical rod 28 and illuminates the kitchen.
The injection nozzle 22 injects air so as to generate the wall jet from the upper outer side of the hollow cylindrical rod 28. The injection nozzle 22 is preferably provided to generate the wall jet at a place θ1 on the outer circumference of the hollow cylindrical rod 28, where an angle from a plane parallel to the inlet 12a is 80 degrees to 100 degrees.
The air stream guide 30 includes a connecting device 31 provided at the sides of the air stream guide 30 and connecting the air stream guide 30 to the hollow cylindrical rod 28 such that an upper gap between the air stream guide 30 and the hollow cylindrical rod 28, through which the wall jet is introduced, is wider than a lower gap therebetween through which the wall jet passes.
In particular, the widest upper gap between the air stream guide 30 and the hollow cylindrical rod 28 is about 8 mm, the narrowest lower gap between the air stream guide 30 and the hollow cylindrical rod 28 is about 6 mm, and preferably, the size of the gaps gradually decreases closer to the lower side of the hollow cylindrical rod 28.
The air stream guide 30 is provided at a position θ2 where the air stream generated by the wall jet is separated. The air stream guide 30 is preferably extended from the position where an angle, from the position θ1 where the wall jet is generated on the outer circumference of the hollow cylindrical rod 28 to the position on the hollow cylindrical rod 28 in the direction that the air stream flows, is 80 degrees to 100 degrees.
Here, the air stream guide 30 preferably has a length from a position θ2 where the air stream generated by the wall jet is separated to a position θ3, wherein an angle from the position θ2 to the position θ3 is 20 degrees to 40 degrees.
The exhaust hood constructed as described above is operated as follows.
The exhaust hood according to the first embodiment of the present invention operates the exhaust fan 16 to suck the indoor polluted air into the body 12 and the wall jet generator 20 during cooking.
When the wall jet fan motor 24 is activated to suck the air at the upper side of the body 12, the sucked air passes through the discharge pipe 26 and is jetted on the upper side of the hollow cylindrical rod 28 by the injection nozzle 22.
Then, on the outer circumference of the hollow cylindrical rod 28, the wall jet is generated and the air stream is formed along the outer circumference of the hollow cylindrical rod 28, and a negative pressure is generated at a region A where the wall jet and the air stream are generated.
This phenomenon referred to as the Coanda effect and is characterized in that a jet flowing along a wall tends to flow along the wall even if the wall is curved. In particular, the Coanda effect is phenomenon that a fluid tends to adhere to and flow along a convex surface, and this phenomenon is caused by viscosity of fluid.
The wall jet produced by the injection nozzle 22 is generated at the upper outer circumference of the hollow cylindrical rod 28, that is, at the place θ1 on the outer circumference of the hollow cylindrical rod 28, where an angle from a plane parallel to the inlet 12a is 80 degrees to 100 degrees as seen from the left side of the hollow cylindrical rod 28, flows along the outer circumference of the hollow cylindrical rod 28, and is separated at the position θ2 where an angle, from the position θ1 where the wall jet is generated on the outer circumference of the hollow cylindrical rod 28 in the direction that the air stream is formed, is 80 degrees to 100 degrees.
Since the air stream guide 30 is provided at the position θ2 where the air stream formed by the wall jet is separated, the wall jet is not separated, but is introduced into the upper gap between the air stream guide 30 and the hollow cylindrical rod 28, and then another negative pressure occurs at the lower region B while the wall jet passes through the lower gap.
The wall jet generator 20 preferably injects the air such that the velocity of the air passing through the gap between the air stream guide 30 and the hollow cylindrical rod 28 can be maintained in the range of 3 m/s to 5 m/s.
Since the air stream guide 30 has a length equal to the length from the position θ2 where the air stream formed by the wall jet is separated to the position where the angle is 20 degrees to 40 degrees, the air stream, after passing through the air stream guide 30, is guided to the inlet 12a of the body 12.
Thus, the polluted air, generated when cooking and escaped to a place far from the inlet 12a of the body 12, is led to the region B of the lower side of the hollow cylindrical rod 28 where the negative pressure is generated by the air stream guide 30, and the polluted air not collected into the region B of the lower side of the body 12 ascends due to its own buoyancy and is led to the region A of the upper side of the hollow cylindrical rod 28 where the air stream is generated by the wall jet generated by the wall jet generator 20, so that the air streams of the polluted air is guided into the inlet 12a of the body.
The air streams led to the regions A and B are guided into a collecting area near to the inlet 12a of the exhaust hood toward the filter 14, and are sucked into the body 12 of the exhaust hood after passing through the filter, so that the collection efficiency is increased.
Fig. 3 is a view illustrating comparison of streamlines formed around the front side of the exhaust hood according to the first embodiment of the present invention with streamlines formed around the front side of the exhaust hood without the air stream guide.
As shown in the left-side drawing of Fig. 3, in the exhaust hood including the wall jet generator without the air stream guide, the air stream formed by the separation of the wall jet at the position θ2 where the air stream generated by the wall jet is separated is spaced apart from the lower side of the body 12, so that the separated wall jet does not substantially flow to the inlet 12a.
On the contrary, as shown in the right-side drawing of Fig. 3, in the exhaust hood including the air stream guide and the wall jet generator, the air stream guide 30, provided at the position θ2 where the air stream formed by the wall jet is separated, guides the separated wall jet to flow along the outer circumference of the hollow cylindrical rod 28 again, so that the pollute air effectively heads the inlet 12a.
Fig. 4 is a sectional view illustrating the exhaust hood according to the second embodiment of the present invention.
The exhaust hood according to the second embodiment of the present invention, as shown in Fig. 4, is constructed such that a wall jet fan motor 24' sucks air in the body instead of air in front of the body 12 so as to generate the wall jet using recirculation of the air sucked into the body 12. Since the components, except for the wall jet fan motor 24', and the operation of the exhaust hood according to the second embodiment of the present invention are identical to those of the exhaust hood according to the first embodiment of the present invention, identical reference numerals are assigned to like components and their description will be omitted.
Fig. 5 is a sectional view illustrating the exhaust hood according to the third embodiment of the present invention.
The exhaust hood according to the third embodiment of the present invention, as shown in Fig. 5, is constructed such that the wall jet fan motor 24' recirculates the air in the body 13 so as to generate the wall jet. Moreover, the exhaust hood according to the third embodiment of the present invention is constructed such that a slit 15 is formed at a region where the lower side 13a of the body 13 meets the hollow cylindrical rod 28, so that a part of the wall jet generated by the wall jet generator is directly sucked into the body 13. Since components except for the wall jet fan motor 24' and the body 13 having the slit 15 and operation of the exhaust hood according to the third embodiment of the present invention are identical to those of the exhaust hood according to the first embodiment of the present invention, identical reference numerals are assigned to like components and their description will be omitted.
Although the exhaust hood according to the present invention is described as being installed to the front corner of the outer lower side of the body 12, the wall jet generator and the air steam guide can be provided to the right and left lower corners, respectively.
As described above, the exhaust hood according to the present invention is capable of exhausting the polluted air near to the inlet of the body of the exhaust hood using the conventional exhaust fan effectively. Since the exhaust hood according to the present invention further includes the wall jet generator and the air stream guide for preventing the separation of the wall jet generated by the wall jet generator in order to collect the polluted air spaced apart from the inlet of the body and ineffectively collected by the conventional exhaust hood, the polluted air can be effectively collected without enhancing the performance of the exhaust fan.
In particular, since the polluted air escaped from the front side of the body is collected through negative pressure surfaces respectively formed at the upper and lower sides of the hollow cylindrical rod, the polluted air flowing to a cooker's face is minimized so as to provide clean indoor air.
Moreover, since it is not necessary to increase the output of the exhaust fan installed within the exhaust hood, the exhaust hood can be further provided to the conventional exhaust hood, and the collection efficiency of the polluted air can be enhanced by a small amount of the exhausted air.
The illuminating device is installed in the hollow cylindrical rod provided to the wall jet generator so as to provide an aesthetically pleasing appearance and to improve work efficiency.
Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims

An exhaust hood comprising:
a body (12) including an exhaust fan (16) disposed at the upper side of a food preparation area and exhausting indoor air, and a filter (14) disposed at an inlet (12a) through which the indoor air is sucked and filtering the sucked indoor air;

a wall jet generator (20) for injecting air so as to generate a wall jet flowing along the curved surface at the front side of the body (12); and

an air stream guide (30) disposed a predetermined distance from the curved surface and guiding the air stream generated by the wall jet flowing to the inlet (12a).
The exhaust hood as set forth in claim 1, wherein the air stream guide (30) is disposed at the position where the air stream is generated by the wall jet.
The exhaust hood as set forth in claim 1, wherein the curved surface formed at the front side of the body (12) comprises the outer circumference of a hollow cylindrical rod (28).
The exhaust hood as set forth in claim 3, wherein the air stream guide (30) is constructed such that the position (θ2) where the air stream guide (30) starts is the position where an angle from the position where the wall jet is generated on the hollow cylindrical rod (28) is 80 degrees to 100 degrees in the direction that the air stream is formed, and the position (θ3) where the air stream guide (30) ends is where an angle from the position (θ2) where the air stream guide (30) starts is 20 degrees to 40 degrees.
The exhaust hood as set forth in claim 3, wherein the wall jet generator (20) is constructed such that the position (θ1) where the wall jet is generated on the hollow cylindrical rod (28) is 80 degrees to 100 degrees from a plane parallel to the inlet (12a).
The exhaust hood as set forth in claim 3, wherein the hollow cylindrical rod (28) further includes an illuminating device (29).
The exhaust hood as set forth in claim 1, wherein the wall jet generator (20) maintains the velocity of the air stream guided by the air stream guide (30) within the range of 3 m/s to 5 m/s.
The exhaust hood as set forth in claim 1, wherein the air stream guide (30) is constructed such that an upper gap between the air stream guide (30) and the curved surface where the generated wall jet is introduced is wider than a lower gap between the air stream guide (30) and the curved surface where the wall jet passes.
The exhaust hood as set forth in claim 8, wherein the air stream guide (30) is constructed such that the upper gap between the air stream guide (30) and the curved surface is about 8 mm, and the lower gap between the air stream guide (30) and the curved surface is about 6 mm.
The exhaust hood as set forth in claim 1, wherein the wall jet generator (20) injects the outside air of the body (12).
The exhaust hood as set forth in claim 1, wherein the wall jet generator (20) injects the air introduced into the body (12).
The exhaust hood as set forth in claim 11, wherein the body (12) further includes a slit (15) formed at the lower side of the body (12), through which the wall jet, after passing through the air stream guide (30) is directly introduced into the body (12).