EP1757865A2

EP1757865A2 - Exhaust hood

Info

Publication number: EP1757865A2
Application number: EP06001649A
Authority: EP
Inventors: Seung-Jo Baek; Sang-Bum Sohn; Sung-Bae Song
Original assignee: LG Electronics Inc
Current assignee: LG Electronics Inc
Priority date: 2005-08-23
Filing date: 2006-01-26
Publication date: 2007-02-28
Anticipated expiration: 2026-01-26
Also published as: KR100741786B1; EP1757865A3; KR20070023224A; EP1757865B1

Abstract

An exhaust hood comprising: a hood main body (110) provided with a canopy (111) having an inlet (117), and an exhaustion portion (121) connected to the canopy (111) and having an exhaustion passage (123); and a nozzle unit (140) disposed at a front side of the hood main body (110), and provided with a curved shape portion (141), and a nozzle (143) disposed at an upper side of the curved shape portion (141) along a circumferential direction of the curved shape portion (141) for horizontally discharging air toward a front region of the curved shape portion (141), whereby contaminated air flowing toward a front region of the exhaust hood without being sucked therein can effectively be induced to the inlet (117) to be collected, thereby creating more comfortable cooking circumstance and experimental environment.

Description

The present invention relates to an exhaust hood, and particularly, to an exhaust hood having an improved efficiency for collecting contaminated air.
In general, an exhaust hood is disposed above a cooker such as a gas range or a laboratory table that generate materials causing air pollution like smoke, smells and grease vapor.
Figure 1 is a side sectional view that illustrates one example of an exhaust hood according to the conventional art. Referring to Figure 1, the conventional exhaust hood includes a canopy 21 installed above a cooker 10 having a plurality of burners 11a and 11b spaced at a predetermined distance therebetween, and an exhaust part 31 communicating with the canopy 21 and upwardly protruding from the canopy 21 to a predetermined height.
An inlet 23 is formed at the bottom of the canopy 21, through which the polluted air including pollutants like smoke, smells and grease vapor generated from the cooker 10 is drawn in. Also, a grease filter 24 that can collect pollutants is mounted at the inlet 23.
An exhaust path 33 is formed in the exhaust part 31, through which the polluted air having been introduced through the inlet 23 is exhausted to the outside. An exhaust fan 34 for forcibly taking in the air is installed under the exhaust path 33.
The polluted air including smoke, smells and grease vapor generated as burners 11 a and 11 b of the cooker heat food items is in a buoyancy jet form and increases in width as it ascends.
Thusly, only a portion of the polluted air is exhausted to the outside via the grease filter 24 installed at the inlet 23 and the exhaust path 33, and most of the polluted air is moved to the outside along a bottom surface of the canopy 21, contaminating the ambient air. Such a phenomenon greatly occurs when a food item is heated on the burner 11a disposed at the front side of the cooker 10.
To prevent the phenomenon, a method of increasing a rotation rate of the exhaust fan 34 and thusly increasing an intake force may be used. However, even though the rotation rate of the exhaust fan 34 is increased to increase the intake force, the intake performance is not improved in proportion to the increased rotation force. For this reason, only the intake force of the exhaust fan 34 used in such a method is not enough to guide the polluted air, which is moved to outside along the bottom surface of the canopy 21, to the inlet 23.
Consequently, the conventional exhaust hood cannot prevent the polluted air from moving out from the canopy 21, polluting an upper region (A) of the front side of the canopy 21 and spreading to a room to thus pollute a surrounding environment.
In order to solve the aforementioned problems, an exhaust hood illustrated in Figure 2 has been devised.
Figure 2 is a side sectional view that illustrates another example of a conventional exhaust hood. Referring to Figure 2, the conventional exhaust hood in accordance with another example includes a hood body 51 disposed above a cooker 10 at a predetermined distance therebetween, and a nozzle part 81 installed at a front region of the hood body 51 and downwardly discharging the air.
The hood body 51 includes a canopy 61 installed above the cooker 10, which has a plurality of burners 11a and 11b, at a predetermined distance therebetween, and an exhaust part 71 communicating with the canopy 61 and upwardly protruding from the canopy 61 to a predetermined height.
The nozzle part 81 is formed at a front region of a bottom surface of the canopy 61 and discharges the air downwardly. An air supply fan 83 for blowing the air to the nozzle part 81 is installed in the canopy 61.
A curve shape portion 85 having an arc shaped section which is convex downwardly is formed at a lower side of the front surface of the canopy 61, so that a portion of the air discharged through the nozzle part 81 can flow to a region of the inlet 63 by the so-called coanda effect. By the curved shape portion 85, the polluted air cannot be moved outside the canopy 61 but is guided to the inlet 63.
In the exhaust hood illustrated in Figure 2, the nozzle part 81 is formed at a spot inwardly spaced apart from the front end of the canopy 61 at a predetermined distance. Thusly, the polluted air having ascended inside the canopy 61 can be guided to the inlet 63 by the air discharged through the nozzle part 81. However, the method does not solve the problem that the polluted air ascending to the front end of the canopy 61 is moved out from the front end of the canopy 61 and pollutes an upper region (B).
Therefore, an object of the present invention is to provide an exhaust hood having an improved collecting efficiency of contaminated air
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided an exhaust hood comprising: a hood main body 110 provided with a canopy 111 having an inlet 117, and an exhaustion portion 121 connected to the canopy 111 and having an exhaustion passage 123; and a nozzle unit 140 disposed at a front side of the hood main body 110, and provided with a curved shape portion 141, and a nozzle 143 disposed at an upper side of the curved shape portion 141 along a circumferential direction of the curved shape portion 141 for horizontally discharging air toward a front region of the curved shape portion 141.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.
In the drawings:

Fig. 1 is a lateral sectional view showing a related art exhaust hood according to one embodiment;
Fig. 2 is a lateral sectional view showing a related art exhaust hood according to another embodiment;
Fig. 3 is a perspective view showing an exhaust hood in accordance with a first embodiment of the present invention;
Fig. 4 is a sectional view taken along a line IV-IV of Fig. 3;
Fig. 5 is an enlarged view of a part C of Fig. 4;
Fig. 6 is a perspective view showing an exhaust hood in accordance with a second embodiment of the present invention;
Fig. 7 is a sectional view taken along a line VII-VII of Fig. 6;
Fig. 8 is a perspective view showing an exhaust hood in accordance with a third embodiment of the present invention;
Fig. 9 is a sectional view taken along a line IX-IX of Fig. 8;
Fig. 10 is a lateral sectional view showing an exhaust hood provided with an upper inlet in accordance with a fourth embodiment of the present invention;
Fig. 11 is a lateral sectional view showing an exhaust hood provided with a reflux flow path in accordance with a fifth embodiment of the present invention; and
Fig. 12 is a perspective view showing an exhaust hood provided with a supplementary nozzle unit in accordance with a sixth embodiment of the present invention.

Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings.
Fig. 3 is a perspective view showing an exhaust hood in accordance with a first embodiment of the present invention, Fig. 4 is a sectional view taken along a line IV-IV of Fig. 3, and Fig. 5 is an enlarged view of a part C of Fig. 4.
As shown in Figs. 3 and 4, an exhaust hood in accordance with a first embodiment of the present invention may include a hood main body 110 and a nozzle unit 140 disposed at a front side of the hood main body 110 for discharging air. Each arrow indicates an air flow.
The hood main body 110 may include a canopy 111 disposed at an upper side of the cookware 10 (refer to Fig. 1) with a particular distance therebetween, and an exhaustion portion 121 connected to the canopy 111 and protruding to the upper side of the canopy 111 by a particular height.
The canopy 111 has a rectangular plate shape, and is provided with an inlet 117 disposed at a lower surface of the canopy 111 for sucking air and a grease filter 118 mounted in the inlet 117 for filtering contaminated materials.
An air supply fan 135 for blowing air to the nozzle unit 140 and an air supply motor 136 for driving the air supply fan 135 are disposed in the canopy 111. A partition wall 131 for partitioning an inside of the canopy 111 is formed at a right side of the air supply motor 136 and the air supply fan 135. A suction hole 133 for partially sucking the air passed through the grease filter 118 to the air supply fan 135 is formed at the partition wall 131.
An exhaustion passage 123 for discharging the air from which the contaminated materials are filtered by the grease filter 118 is formed at the exhaustion portion 121. An exhaustion fan 124 for forcibly sucking air and an exhaustion motor 125 for driving the exhaustion fan 124 are mounted at a lower side of the exhaustion passage 123.
Referring to Figs. 4 and 5, the nozzle unit 140 may include a curved shape portion 141, and a nozzle 143 disposed at an upper side of the curved shape portion 141 along its circumferential direction for horizontally discharging air toward a front region of the curved shape portion 141.
The curved shape portion 141 has a cylindrical bar or cylindrical pipe shape of which circular section has a diameter of 40 to 65 mm. A ratio (h/D) of a distance (h) between a center O of the curved shape portion 141 with respect to the diameter D thereof and a lower surface 111 b of the canopy 111 can be 0 to 0.5.
The nozzle 143 is formed at an upper surface of the curved shape portion 141 to thus horizontally discharge air toward the front region of the curved shape portion 141. The nozzle 143 is spaced from the upper surface of the curved shape portion 141 by a gap (d) corresponding to about 1.5 to 4 mm.
An internal angle θ formed between a virtual line L1 for connecting an end of the nozzle 143 to the center O of the curved shape portion 141 and a vertical line Lv passing through the center O of the curved shape portion 141 is preferably 0 to 30° to maximize a coanda effect.
Hereinafter, an operation of the exhaust hood according to the first embodiment will now be explained.
Referring to Figs. 4 and 5, when the exhaustion fan 124 rotates, air flows into the inlet 117. At this time, contaminated materials contained in the contaminated air are removed (filtered) by the grease filter 118, and the air from which the contaminated materials are filtered is discharged to the exterior through the exhaustion passage 123.
When the air supply fan 135 rotates, on the other hand, the air from which the contaminated materials are filtered is partially sucked in the suction hole 133. The sucked air is horizontally discharged toward the front region of the curved shape portion 141 through the nozzle 143 via the air supply passage 137.
The air horizontally discharged through the nozzle 143 flows along the upper surface of the curved shape portion 141 to form a negative pressure region S1 having a minus (-) gauge pressure at the upper and front surfaces of the curved shape portion 141. A progressive path of the contaminated air which is intended to pass through the exhaust hood is curved toward the negative pressure region S1 and thus the contaminated air is induced to the inlet 117 again. Accordingly, a collecting efficiency of the exhaust hood can be improved.
Hereinafter, an exhaust hood in accordance with a second embodiment of the present invention will now be explained. The same reference numerals are provided for the same parts and components as those in the aforementioned and illustrated construction, and the explanation therefor will thus be omitted.
Fig. 6 is a perspective view showing an exhaust hood in accordance with a second embodiment of the present invention, and Fig. 7 is a sectional view taken along a line VII-VII of Fig. 6.
As shown in Figs. 6 and 7, an exhaust hood according to a second embodiment may further comprise a flow guide 170 disposed at one side of the nozzle unit 140 for guiding an air flow and restraining a vortex formation caused by a flow separation.
The flow guide 170 may include a guide portion 173 extending horizontally in a width direction of the curved shape portion 141 and having an arc-sectional shape, and a support portion 175 formed at both sides of the guide portion 173, respectively, and mounted at both sides of the curved shape portion 141, respectively.
The reason which the flow guide 170 should be disposed will be explained as follows.
Referring to Fig. 7, if the internal angle θ formed between the virtual line L1 for connecting the end of the nozzle 143 to the center O of the curved shape portion 141 and the vertical line Lv passing through the center O of the curved shape portion 141 is more than 0°, the negative pressure region S1 extends up to the upper portion of the curved shape portion 141, but, on the other hand, the air is not moved downwardly up to the lower portion of the curved shape portion 141 but separated from the curved shape portion 141 at its middle portion. As a result, the vortex is formed, thereby decreasing the coanda effect.
In order to prevent this problem from occurring, the flow guide 170 is disposed at the lower side of the curved shape portion 141 to guide the air flow downwardly up to the lower side of the curved shape portion 141 and to restrain the vortex formation caused by the flow separation, thereby maximizing the coanda effect.
An operation of the exhaust hood according to the second embodiment will now be explained hereafter.
Referring to Figs. 6 and 7, when the exhaustion fan 124 rotates, air flows into the inlet 117. At this time, contaminated materials contained in the contaminated air are removed (filtered) by the grease filter 118, and the air from which the contaminated materials are filtered is discharged to the exterior through the exhaustion passage 123.
When the air supply fan rotates, on the other hand, the air from which the contaminated materials are filtered is partially sucked in the suction hole 133. The sucked air is horizontally discharged toward the front region of the curved shape portion 141 through the nozzle 143 via the air supply passage 137.
The air horizontally discharged through the nozzle 143 flows along the upper surface of the curved shape portion 141 to form the negative pressure region S1 having the minus (-) gauge pressure at the upper and front surfaces of the curved shape portions 141. Accordingly, the progressive path of the contaminated air which is intended to pass through the exhaust hood is curved toward the negative pressure region S1, and thus the contaminated air is induced to the inlet 117 again.
On the other hand, the flow guide 170 disposed at the lower side of the curved shape portion 141 guides the air flow downwardly up to the lower surface of the curved shape portion 141. Accordingly, the vortex formation caused by the flow separation is restrained to thus maximize the coanda effect. Therefore, the collecting efficiency of the exhaust hood can be improved.
Hereinafter, an exhaust hood in accordance with a third embodiment of the present invention will now be explained. The same reference numerals are provided for the same parts and components as those in the aforementioned and illustrated construction, and the explanation therefor will thus be omitted.
Fig. 8 is a perspective view showing an exhaust hood in accordance with a third embodiment of the present invention, and Fig. 9 is a sectional view taken along a line IX-IX of Fig. 8.
As shown in Figs. 8 and 9, an exhaust hood according to a third embodiment may further comprise a flow plate 180 disposed at one side of the nozzle unit 140 for guiding an air flow and restraining a vortex formation caused by an flow separation.
An installation purpose of the flow plate 180 is the same as the flow guide 170 shown in Fig 6 and the explanation therefor will thus be omitted.
The flow plate 180 may include a plate portion 181 extending in a width direction of the curved shape portion 141 and spaced downwardly from the lower side of the curved shape portion 141 by a particular interval, and a connection portion 183 formed at both sides of the plate portion 181, respectively, and mounted at both sides of the curved shape portion 141, respectively.
The plate portion 181 is disposed at the lower side of the canopy 111 with the particular interval therebetween such that a ratio (Db/D) between an interval Db between the lower surface 111b of the curved shape portion 141 and the plate portion 181 and the diameter D of the curved shape portion 141 can be 0.2 to 1.0 in order to guide the air to the maximum.
An inflow guide portion 181a for facilitating a guiding of air to a space S2 formed between the curved shape portion 141 and the plate portion 181 is formed to have a curved surface at a front end of he plate portion 181.
The inflow guide portion 181 a is formed at the front end of the plate portion 181 such that a ratio (Da/D) between the interval Da between the vertical line Lv passing through the center O of the curved shape portion 141 and the inflow guide portion 181 a and the diameter D of the curved shape portion 141 can be 0 to 0.5, thereby guiding the air to the maximum.
An operation of the exhaust hood according to the third embodiment will now be explained hereafter.
Referring to Fig. 9, when the exhaustion fan 124 rotates, air flows into the inlet 117. At this time, contaminated materials contained in the contaminated air are removed (filtered) by the grease filter 118, and the air from which the contaminated materials are filtered is discharged to the exterior through the exhaustion passage 123.
When the air supply fan 135 rotates, on the other hand, the air from which the contaminated materials are filtered is partially sucked in the suction hole 133. The sucked air is horizontally discharged toward the front region of the curved shape portion 141 through the nozzle 143 via the air supply passage 137.
The air horizontally discharged through the nozzle 143 flows along the upper surface of the curved shape portion 141 to form the negative pressure region S1 having the minus (-) gauge pressure at the upper and front surfaces of the curved shape portions 141. Accordingly, the progressive path of the contaminated air which is intended to pass through the exhaust hood is curved toward the negative pressure region S1, and thus the contaminated air is induced to the inlet 117 again.
At this time, the flow plate 180 disposed at the lower side of the curved shape portion 141 guides the air flow downwardly up to the lower side of the curved shape portion 141, and thus restrains the vortex formation caused by the flow separation, thereby maximizing the coanda effect.
An exhaust hood according to a fourth embodiment of the present invention will now be explained hereafter. The same reference numerals are provided for the same parts and components as those in the aforementioned and illustrated construction, and the explanation therefor will thus be omitted.
Fig. 10 is a lateral sectional view showing an exhaust hood provided with an upper inlet in accordance with a fourth embodiment of the present invention. As shown in Fig. 10, unlike in the first embodiment in which the air sucked through the inlet 117 is supplied to the nozzle 143, in the fourth embodiment, the air sucked through the grease filter 155 disposed in the upper inlet 153 formed at an upper surface 111a of the canopy 111 is supplied as air to be discharged through the nozzle 143.
In the aforementioned construction, when the air supply fan 135 rotates, air at the upper side of the canopy 111 is sucked through the grease filter 155 disposed in the upper inlet 153. The sucked air is discharged through the nozzle 143 via the air supply passage 137. Afterwards, the operation and effect of the discharged air have already been explained, and thus the explanation therefor will be omitted.
Hereinafter, an exhaust hood in accordance with a fifth embodiment of the present invention will be explained. The same reference numerals are provided for the same parts and components as those in the aforementioned and illustrated construction, and the explanation therefor will thus be omitted.
Fig. 11 is a lateral sectional view showing an exhaust hood provided with a reflux flow path in accordance with a fifth embodiment of the present invention.
As shown in Fig. 11, unlike in the first embodiment in which the air sucked through the inlet 117 is supplied to the nozzle 143, the air which is intended to pass through the exhaustion passage 123 is partially supplied as air to be discharged through the nozzle 143 in the fifth embodiment.
For this, a reflux flow path 161 of which one end is connected to the exhaustion passage 123 and the other end is connected to the air supply passage 137 is formed in both the canopy 111 and the exhaustion portion 121. Accordingly, the air supply fan 135(refer to Fig. 4) and the air supply motor 136(refer to Fig. 4) are not required any more, and thus fabricating cost therefor can be reduced.
In the aforementioned construction, when the exhaustion fan 124 rotates, the air passing through the exhaustion passage 123 is partially discharged through the nozzle 143 via the reflux flow path 161 and the air supply passage 137. The operation and effect of the discharged air have been explained in the first embodiment and the explanation therefor will thus be omitted.
An exhaust hood according to a sixth embodiment of the present invention will now be explained hereafter. The same reference numerals are provided for the same parts and components as those in the aforementioned and illustrated construction, and the explanation therefor will thus be omitted.
Fig. 12 is a perspective view showing an exhaust hood provided with a supplementary nozzle unit in accordance with a sixth embodiment of the present invention.
As shown in Fig. 12, an exhaust hood according to a sixth embodiment may comprise the nozzle unit 140 for preventing contaminated air from flowing toward the front region of the canopy 111 without being sucked therein, and a supplementary nozzle unit 190 for preventing the contaminated air from flowing toward each lateral region of the canopy 111 without being sucked therein.
The construction and operation of the nozzle unit 140 have been explained in the first embodiment and the explanation therefor will thus be omitted.
The supplementary nozzle unit 190 may include a lateral curved shape portion 191, and a lateral nozzle 193 disposed at an upper side of the lateral curved shape portion 191 along its circumferential direction for horizontally discharging air toward a front region of the lateral curved shape portion 191.
The construction and operation of the lateral curved shape portion 191 and the lateral nozzle 193 of the supplementary nozzle unit 190 are the same as the curved shape portion 141 and the nozzle 143 of the nozzle unit 140, and thus the explanation therefor will be omitted. The supplementary nozzle unit 190 can allow the contaminated air flowing toward the lateral region of the canopy 111 to be collected, and accordingly the overall collecting efficiency of the exhaust hood can be improved.
The exhaust hood having explained according to the embodiments of the present invention will have the following advantages.
First, the curved shape portion and the nozzle for horizontally discharging air toward the front region of the curved shape portion are provided such that the contaminated air flowing toward the front region of the exhaust hood without being sucked therein can effectively be induced to the inlet to thus be collected. Therefore, more comfortably cooking circumstance and experimental environment can be created.
Second, for installing the flow guide or the flow plate at the one side of the nozzle unit, the air flow can be guided downwardly up to the lower surface of the curved shape portion. Accordingly, the vortex formation caused by the flow separation can be restrained to thereby improve the collecting efficiency of the exhaust hood.
Third, when the supplementary nozzle unit is additionally provided, even the contaminated air flowing toward the lateral region of the exhaust hood without being sucked therein can be induced to the inlet to be collected. Accordingly, more comfortably cooking circumstance and experimental environment can be created.
As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalence of such metes and bounds are therefore intended to be embraced by the appended claims.

Claims

An exhaust hood comprising:
a hood main body (110) provided with a canopy (111) having an inlet (117), and an exhaustion portion (121) connected to the canopy (111) and having an exhaustion passage (123); and

a nozzle unit (140) disposed at a front side of the hood main body (110), and provided with a curved shape portion (141), and a nozzle (143) disposed at an upper side of the curved shape portion (141) along a circumferential direction of the curved shape portion (141) for horizontally discharging air toward a front region of the curved shape portion (141).
The exhaust hood of claim 1, further comprising:
an air supply passage (137) for inducing air to the nozzle (143);

an air supply fan (135) for blowing air to the air supply passage (137);

an air supply motor (136) for driving the air supply fan (135); and

a partition wall (131) connected to the air supply passage (137), and provided with a suction hole (133) for inducing air sucked through the inlet (117) to the air supply fan (135).
The exhaust hood of claim 1, further comprising:
an air supply passage (137) for inducing air to the nozzle (143);

an air supply fan (135) for blowing air to the air supply passage (137);

an air supply motor (136) for driving the air supply fan (135); and

an upper inlet (153) connected to the air supply passage (137) and formed at an upper surface of the canopy (111) to thus induce air to the air supply fan (135).
The exhaust hood of claim 1, further comprising:
an air supply passage (137) for inducing air to the nozzle (143); and

a reflux flow path (161) connected to the air supply passage (137) for supplying the air passing through the exhaustion passage (123) to the nozzle unit (140).
The exhaust hood of any of claims 1 to 4, wherein a ratio (h/D) of a distance (h) between a center O of the curved shape portion (141) with respect to the diameter D thereof and a lower surface (111 b) of the canopy (111) is 0 to 0.5.
The exhaust hood of any of claims 1 to 5, wherein the curved shape portion (141) has a cylindrical bar or cylindrical pipe shape of which circular section has a diameter D of 40 to 65 mm.
The exhaust hood of any of claims 1 to 6, wherein the nozzle (143) is spaced from the upper surface of the curved shape portion (141) by 1.5 to 4 mm.
The exhaust hood of any of claims 1 to 7, wherein an internal angle θ formed between a virtual line L1 for connecting an end of the nozzle (143) to the center O of the curved shape portion (141) and a vertical line Lv passing through the center O of the curved shape portion (141) is 0 to 30°.
The exhaust hood of any of claims 1 to 8, wherein a speed of air discharged through the nozzle (143) is 3 to 5 m/sec.
The exhaust hood of any of claims 1 to 9, further comprising a flow guide (170) provided with:
a guide portion (173) extending in a width direction of the curved shape portion (141) and having an arc-sectional shape; and

a support portion (175) formed at both sides of the guide portion (173), respectively, and mounted at both sides of the curved shape portion (141), respectively.
The exhaust hood of any of claims 1 to 10, further comprising a flow plate (180) provided with:
a plate portion (181) extending in the width direction of the curved shape portion (141), and spaced downwardly from the lower side of the curved shape portion (141); and

a connection portion (183) formed at both sides of the plate portion, respectively, and mounted at both sides of the curved shape portion (141), respectively.
The exhaust hood of claim 11, wherein a ratio (Db/D) between an interval Db between the lower surface (111b) of the curved shape portion (141) and the flow plate (180) and the diameter D of the curved shape portion (141) is 0.2 to 1.0.
The exhaust hood of claim 11 or 12, wherein an inflow guide portion (181 a) is formed at a front end of the plate portion (181).
The exhaust hood of claim 13, wherein a ratio (Da/D) between the interval Da between the vertical line Lv passing through the center O of the curved shape portion (141) and the inflow guide portion (181 a) and the diameter D of the curved shape portion (141) is 0 to 0.5.
The exhaust hood of any of claims 1 to 14, further comprising:
a supplementary nozzle unit (190) disposed at both sides of the hood main body (110), respectively, and provided with a lateral curved shape portion (191), and a lateral nozzle (193) disposed at an upper side of the lateral curved shape portion (191) along a circumferential direction thereof for horizontally discharging air toward a front region of the lateral curved shape portion (191).
A method of operating an exhaust hood according to any of claims 1 to 15.