Exhaust and internal circulation type range hood

Abstract

The utility model provides a kind of outside and internal circulation formula range hood, the outside and internal circulation formula range hood includes internal circulation module, outside exhaust module, smoke collecting hood and flue, the outside exhaust module includes main fan and outside exhaust duct, the internal circulation module includes circulating fan and internal circulation duct, the import of the outside exhaust duct is communicated with the smoke collecting hood, the outlet of the outside exhaust duct is communicated with the flue, the import of the internal circulation duct is communicated between the outside exhaust duct and the flue, along the height direction of the outside and internal circulation formula range hood, the internal circulation duct is arranged above the main fan, the main fan is arranged in the outside exhaust duct, the circulating fan is arranged in the internal circulation duct, the axis of the main fan is vertically arranged with the axis of the circulating fan.

Description

Technical Field

[0001] This utility model specifically relates to an external exhaust and internal circulation type range hood. Background Technology

[0002] External exhaust range hoods are the most common type of household range hood. They vent fumes to a shared flue or directly outdoors via a duct. However, when kitchen space is limited or the air supply location (such as the relative position of doors and windows) is not ideal, external exhaust range hoods may experience severe smoke leakage. In this case, the capture efficiency of the external exhaust range hood drops significantly. Current technology typically uses range hoods with internal circulation and smoke purification functions to address the smoke leakage issues that may occur with external exhaust range hoods and in scenarios where an external duct cannot be connected. Internal circulation mode can be used to filter and purify the fumes before directly venting them indoors. However, existing range hoods that combine external exhaust and internal circulation smoke purification functions usually have the internal circulation duct and the external exhaust duct arranged side by side. This means that when the range hood switches to internal circulation, the path of the fumes is similar to that of external exhaust, resulting in a longer smoke purification time. Furthermore, the internal circulation duct often contains a filter module, which increases the resistance of the fumes during smoke purification in internal circulation mode, further increasing the purification time and leading to a poor user experience. Utility Model Content

[0003] The technical problem to be solved by this utility model is to overcome the shortcomings of existing range hoods in terms of long time and low smoke purification efficiency when using internal circulation, and to provide a range hood with both external exhaust and internal circulation.

[0004] The present invention solves the above-mentioned technical problems through the following technical solution:

[0005] An external exhaust and internal circulation range hood includes an internal circulation module, an external exhaust module, a smoke collection hood, and an exhaust pipe. The external exhaust module includes a main fan and an external exhaust duct. The internal circulation module includes a circulation fan and an internal circulation duct. The inlet of the external exhaust duct is connected to the smoke collection hood, and the outlet of the external exhaust duct is connected to the exhaust pipe. The inlet of the internal circulation duct connects to the space between the external exhaust duct and the exhaust pipe. Along the height direction of the external exhaust and internal circulation range hood, the internal circulation duct is located above the main fan, the main fan is located inside the external exhaust duct, and the circulation fan is located inside the internal circulation duct. The axis of the main fan is perpendicular to the axis of the circulation fan.

[0006] In this design, by aligning the axis of the circulating fan perpendicular to that of the main fan, compared to aligning them parallel, space is saved within the range hood, resulting in a more compact interior. This reduces the flow path of cooking fumes, lowers resistance to their entry into the internal circulation duct, shortens purification time, and improves purification efficiency. Furthermore, by placing the internal circulation duct above the main fan, the flow path of cooking fumes is optimized. Upon entering the internal circulation duct, fumes first pass through the main fan and the exhaust duct before flowing into the internal circulation duct through its inlet. The main fan accelerates the flow of fumes, meaning that fumes entering the internal circulation duct are accelerated by both the main fan and the circulating fan. Compared to using a single fan, this increases the flow velocity of the fumes, thus improving purification efficiency.

[0007] Preferably, the exhaust duct extends along the height direction of the exhaust and recirculation range hood and is located close to the first side of the exhaust and recirculation range hood. The recirculation duct extends along the length direction of the exhaust and recirculation range hood, and the inlet of the recirculation duct faces the first side of the exhaust and recirculation range hood. The distance between the inlet of the recirculation fan and the first side of the exhaust and recirculation range hood is n1, where n1 = 1.5 to 1.8L, and L is the length of the main fan along the length direction of the exhaust and recirculation range hood.

[0008] In this solution, the path of oil fumes entering the internal circulation duct is optimized by limiting the distance between the inlet of the circulating fan and the first side of the exhaust and internal circulation range hoods.

[0009] Preferably, along the height direction of the external exhaust and internal circulation range hood, the distance between the axis of the circulation fan and the side wall of the main fan near the exhaust pipe is m1, where m1 = 0.2-0.7D1, and D1 is the inlet diameter of the circulation fan.

[0010] In this solution, the above settings are used to reduce the path of oil fumes entering the internal circulation duct.

[0011] Preferably, the outlet of the main fan forms an angle of 90-180° with the axis of the circulating fan.

[0012] In this solution, the above settings are used to optimize the flow path of oil fumes within the external exhaust duct.

[0013] Preferably, the exhaust module further includes an air guide duct, which is disposed in the exhaust duct. The first end of the air guide duct is connected to the outlet of the main fan, and the second end of the air guide duct extends into the exhaust duct. The plane of the second end of the air guide duct is parallel to the axis of the circulating fan.

[0014] In this scheme, the above settings are used to achieve a 180° angle between the outlet of the main fan and the axis of the circulating fan.

[0015] Preferably, the sidewall of the air duct near the first side of the external exhaust and internal circulation range hood forms an angle of 2-5° with the first side of the external exhaust and internal circulation range hood.

[0016] In this solution, the above-mentioned settings ensure that the fumes entering the exhaust duct can be smoothly transferred through the duct, preventing the fumes flowing out of the exhaust fan from being obstructed.

[0017] Preferably, the internal circulation module further includes a filter section, which is disposed in the internal circulation duct and located between the inlet of the internal circulation duct and the circulation fan. The distance between the side of the filter section facing the circulation fan and the inlet of the circulation fan is greater than or equal to 50 mm.

[0018] In this solution, by setting up the filter section to purify the fumes, the flow rate of the fumes in the internal circulation duct is guaranteed by limiting the distance between the filter section and the inlet of the circulating fan, thereby shortening the time required for fume purification.

[0019] Preferably, a guide plate is also provided at the inlet of the internal circulation duct. The external exhaust and internal circulation range hoods open or close the internal circulation duct through the guide plate. When the guide plate closes the inlet of the internal circulation duct, the circulation fan is turned off. When the guide plate forms a 47° angle with the inlet of the internal circulation duct, the guide plate opens the inlet of the internal circulation duct, and the circulation fan is turned on.

[0020] In this solution, the above settings are used to switch between external exhaust ducts and internal recirculation ducts.

[0021] Preferably, the cross-section of the guide plate is an arc, the center of the arc is located above the axis of the circulating fan, the radius of the arc is 155-165mm, the chord length of the arc is 250-255mm, and the chord length of the arc forms an angle of 132-150° with the first side of the external exhaust and internal circulation range hood.

[0022] In this solution, the above settings ensure that when the guide plate opens the inlet of the internal circulation duct, the oil fumes come into contact with the guide plate more smoothly, thus avoiding obstruction of the oil fume flow.

[0023] Preferably, the cross-section of the guide plate is a straight line.

[0024] In this solution, the above settings are used to open or close the inlet of the internal circulation air.

[0025] The positive and progressive effects of this invention are as follows: By setting the axis of the circulating fan perpendicular to the axis of the main fan, compared to setting the axes of the circulating fan and the main fan parallel, this saves space inside the range hood, making the interior more compact. This reduces the flow path of the fumes, thereby reducing the resistance to the fumes flowing into the inner circulation duct, shortening the smoke removal time, and improving the smoke removal efficiency. Furthermore, by placing the inner circulation duct above the main fan, the flow path of the fumes is optimized. When the fumes enter the inner circulation duct, they first need to flow through the main fan and the exhaust duct before entering the inner circulation duct through the inlet. The fumes can be accelerated by the main fan; that is, the fumes entering the inner circulation duct flow through both the main fan and the circulating fan. Compared to using a single fan, the flow speed of the fumes increases, thus improving the smoke removal efficiency. Attached Figure Description

[0026] Figure 1 This is a perspective view of a preferred embodiment of the external exhaust and internal circulation range hood of the present invention.

[0027] Figure 2 This is a schematic diagram of the internal circulation module and the external discharge module of a preferred embodiment of the present invention.

[0028] Figure 3 This is a schematic diagram of the closed internal circulation air duct of a preferred embodiment of the present invention.

[0029] Figure 4 This is a schematic diagram of the internal circulation air duct opening in a preferred embodiment of the present invention.

[0030] Explanation of reference numerals in the attached figures:

[0031] Inner loop module 1

[0032] Circulating fan 11

[0033] Internal circulation air duct 12

[0034] Filter section 13

[0035] External discharge module 2

[0036] Main fan 21

[0037] External exhaust duct 22

[0038] Air duct 23

[0039] Smoke hood 3

[0040] Smoke exhaust pipe 4

[0041] First side 5

[0042] Deflector 6

[0043] Height direction A

[0044] Length direction B

[0045] Width direction C Detailed Implementation

[0046] The present invention will be described more clearly and completely below with reference to the accompanying drawings, using a preferred embodiment.

[0047] This embodiment provides a range hood with both external exhaust and internal circulation, the specific structure of which is as follows: Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, the external exhaust and internal circulation range hood includes an internal circulation module 1, an external exhaust module 2, a smoke collection hood 3, and a smoke exhaust pipe 4. The external exhaust module 2 includes a main fan 21 and an external exhaust duct 22. The internal circulation module 1 includes a circulation fan 11 and an internal circulation duct 12. The inlet of the external exhaust duct 22 is connected to the smoke collection hood 3, and the outlet of the external exhaust duct 22 is connected to the smoke exhaust pipe 4. The inlet of the internal circulation duct 12 is connected between the external exhaust duct 22 and the smoke exhaust pipe 4. Along the height direction A of the external exhaust and internal circulation range hood, the internal circulation duct 12 is located above the main fan 21. The main fan 21 is located inside the external exhaust duct 22, and the circulation fan 11 is located inside the internal circulation duct 12. The axis of the main fan 21 is perpendicular to the axis of the circulation fan 11.

[0048] Specifically, taking the first side 5 of the external exhaust and internal circulation range hood as the Y-axis and the axis of the circulation fan 11 as the X-axis as an example, the axis of the circulation fan 11 extends towards the Y-axis, and the thickness direction of the circulation fan 11 coincides with the length direction B of the external exhaust and internal circulation range hood. Meanwhile, the axis of the main fan 21 extends along the width direction C of the external exhaust and internal circulation range hood and is perpendicular to the axis of the circulation fan 11. That is, the thickness direction of the main fan 21 coincides with the width direction C of the external exhaust and internal circulation range hood. Compared to the parallel arrangement of the circulation fan 11 and the main fan 21... With the thickness directions of both the circulating fan 11 and the main fan 21 coinciding with the width direction C of the external exhaust and internal circulation range hoods, the axis of the circulating fan 11 extends towards the Y-axis and is perpendicular to the axis of the main fan 21. This reduces the internal space occupied by the internal circulation module 1 within the external exhaust and internal circulation range hoods, saving space and making the range hood more compact. This reduces the flow path of fumes, thereby lowering the resistance to fumes flowing into the internal circulation duct 12, reducing the smoke removal time, and improving smoke removal efficiency.

[0049] Furthermore, by placing the internal circulation duct 12 above the main fan 21, the flow path of the oil fumes is optimized. Compared to placing the internal circulation duct 12 below the main fan 21, the oil fumes entering the internal circulation duct 12 first need to flow through the main fan 21 and the exhaust duct 22 and then flow into the internal circulation duct 12 through the inlet. The oil fumes can be accelerated by the main fan 21. That is, the oil fumes entering the internal circulation duct 12 flow in through the main fan 21 and the circulation fan 11. Compared to setting up a single fan, the flow speed of the oil fumes increases, thereby improving the smoke removal efficiency.

[0050] Furthermore, in this embodiment, the exhaust duct 22 extends along the height direction A of the exhaust and internal circulation range hood and is located close to the first side 5 of the exhaust and internal circulation range hood. The internal circulation duct 12 extends along the length direction B of the exhaust and internal circulation range hood, and the inlet of the internal circulation duct 12 is located facing the first side 5 of the exhaust and internal circulation range hood. The distance between the inlet of the circulation fan 11 and the first side 5 of the exhaust and internal circulation range hood is n1, where n1 = 1.5~1.8L, and L is the length of the main fan 21 along the length direction B of the exhaust and internal circulation range hood.

[0051] Specifically, the fumes need to flow through the main fan 21 and the exhaust duct 22, and through the inlet of the internal circulation duct 12 between the exhaust duct 22 and the smoke exhaust pipe 4 to the circulation fan 11. In this embodiment, the value of L is in the range of 320-400mm, and n1 = 1.5~1.8L. That is, the size of the main fan 21 in the length direction B is limited, and the distance between the inlet of the circulation fan 11 and the first side 5 of the exhaust and internal circulation range hood is limited, so that the flow path of the fumes entering the exhaust duct 22 and the internal circulation duct 12 is shortened accordingly, thereby optimizing the path of the fumes entering the internal circulation duct 12.

[0052] Furthermore, along the height direction A of the external exhaust and internal circulation range hood, the distance between the axis of the circulation fan 11 and the side wall of the main fan 21 near the exhaust pipe 4 is m1, where m1 = 0.2-0.7D1, and D1 is the inlet diameter of the circulation fan 11.

[0053] Specifically, compared to the arrangement where the axis of the circulating fan 11 coincides with the side wall of the main fan 21 near the exhaust pipe 4, the axis of the circulating fan 11 is positioned above the main fan 21. The distance between the axis of the circulating fan 11 and the side wall of the main fan 21 near the exhaust pipe 4 is m1, where m1 = 0.2-0.7D1. This design allows the fumes to flow out of the main fan 21, pass through the external exhaust channel 22, and then flow into the internal circulation duct 12, reducing the resistance encountered by the fumes and effectively shortening the path for the fumes to enter the internal circulation duct 12. It is understandable that the value range of m1 can be obtained by substituting the actual value of D1.

[0054] In this embodiment, the outlet of the main fan 21 forms an angle of 90-180° with the axis of the circulating fan 11.

[0055] Specifically, taking the example where the outlet sidewall of the main fan 21 is parallel to the first side 5 of the exhaust and recirculation range hood as an example, the outlet sidewall of the main fan 21 extends along the height direction A of the exhaust and recirculation range hood, while the axis of the recirculation fan 11 is perpendicular to the first side 5 of the exhaust and recirculation range hood, that is, the axis of the recirculation fan forms a 90° angle with the outlet sidewall of the main fan 21. This allows the fumes to flow close to the first side 5 of the exhaust and recirculation range hood and quickly flow into the inlet of the recirculation duct 12 when it is opened.

[0056] In addition, in this embodiment, the exhaust module 2 also includes an air duct 23, which is disposed in the exhaust duct 22. The first end of the air duct 23 is connected to the outlet of the main fan 21, and the second end of the air duct 23 extends into the exhaust duct 22. The plane of the second end of the air duct 23 is parallel to the axis of the circulating fan 11.

[0057] Specifically, the outlet sidewall of the main fan 21 is positioned facing the first side 5 of the exhaust and internal circulation range hood, meaning that the fumes flowing from the main fan 21 flow close to the first side 5 of the exhaust and internal circulation range hood. A guide pipe 23, which is an arc-shaped pipe, is connected to the outlet sidewall of the main fan 21 to guide the fumes flowing from the main fan 21 into the exhaust duct 22. It should be noted that in this embodiment, the second end of the guide pipe 23 is parallel to the axis of the circulation fan 11. This means that the addition of the guide pipe 23 effectively guides the fumes and makes the outlet of the main fan 21 form a 180° angle with the axis of the circulation fan 11.

[0058] Of course, in other embodiments, the second end of the air duct 23 may also form other angles within the range of 90-180° with the axis of the circulating fan 11. The angle adjustment method can be optimized by using finite element software in the prior art, which incorporates the parameters of the external exhaust and internal circulation range hoods. This is prior art and will not be elaborated on here.

[0059] In this embodiment, the side wall of the air guide duct 23 near the first side 5 of the external exhaust and internal circulation range hood forms an angle of 2-5° with the first side 5 of the external exhaust and internal circulation range hood. By setting an angle β on the side wall of the air guide duct 23 near the first side 5 of the external exhaust and internal circulation range hood, the oil fumes flowing out of the main fan 21 are further guided and smoothly transitioned, avoiding a sharp decrease in the flow velocity of the oil fumes flowing out of the main fan 21, which would affect the smoke extraction effect.

[0060] Preferably, the side wall of the air duct 23 near the first side 5 of the external exhaust and internal circulation range hood forms a 2.5° angle with the first side 5 of the external exhaust and internal circulation range hood.

[0061] In this embodiment, the internal circulation module 1 further includes a filter section 13, which is disposed in the internal circulation duct 12 and located between the inlet of the internal circulation duct 12 and the circulation fan 11. The distance between the side of the filter section 13 facing the circulation fan 11 and the inlet of the circulation fan 11 is greater than or equal to 50mm.

[0062] Specifically, the axis of the filter section 13 coincides with the axis of the circulating fan 11. Along the extension direction of the inner circulation duct 12, the filter section 13 and the circulating fan 11 are arranged sequentially. By limiting the distance between the inlet of the filter section 13 and the circulating fan 11, the flow rate of the oil fumes within the inner circulation duct 12 is maintained while the filter section 13 purifies the oil fumes, thus shortening the fume purification time. It is understood that the filter section 13 is a filtration structure in the prior art that purifies oil fumes and allows the purified oil fumes to be directly discharged into the room, thereby realizing the internal circulation function of the inner circulation module 1.

[0063] Preferably, the distance between the side of the filter section 13 facing the circulating fan 11 and the inlet of the circulating fan 11 is 80mm. By performing fluid analysis using existing finite element software, and optimizing the internal circulation duct 12 and the external exhaust duct 22, and by aligning the axis of the circulating fan 11 perpendicular to the axis of the main fan 21, the fumes can be guided into the filter section 13 via the shortest path and with the lowest flow resistance. Compared to a configuration where the circulating fan 11 and the main fan 21 are arranged side-by-side, with the thickness directions of both the circulating fan 11 and the main fan 21 coinciding with the width direction C of both the external and internal circulation range hoods, this method can improve smoke removal efficiency by more than 5 percentage points and reduce wind resistance by more than 10%.

[0064] like Figure 3 and Figure 4 As shown, in this embodiment, a guide plate 6 is also provided at the inlet of the internal circulation duct 12. The external exhaust and internal circulation range hoods open or close the internal circulation duct 12 through the guide plate 6. When the guide plate 6 closes the inlet of the internal circulation duct 12, the circulation fan 11 is turned off. When the guide plate 6 forms a 47° angle with the inlet of the internal circulation duct 12, the guide plate 6 opens the inlet of the internal circulation duct 12, and the circulation fan 11 is turned on.

[0065] Specifically, one end of the guide plate 6 is hinged to the inlet of the internal circulation duct 12 near the exhaust pipe 4. The guide plate 6 can be driven by a servo motor, as is done in the prior art, to open or close the inlet of the internal circulation duct 12 according to whether smoke is escaping from the external exhaust duct 22. This is prior art and will not be elaborated further here. When the guide plate 6 forms a 0° angle with the inlet of the internal circulation duct 12, that is, when the guide plate 6 is in contact with the inlet of the internal circulation duct 12, the inlet of the internal circulation duct 12 is closed. When the guide plate 6 forms a 47° angle with the inlet of the internal circulation duct 12, the guide plate 6 opens the inlet of the internal circulation duct 12, so that the fumes flowing out of the self-propelled fan 21 can enter the internal circulation duct 12, thereby filtering the fumes before exhausting them into the room. In this embodiment, the outlet of the internal circulation duct 12 is offset from the exhaust pipe 4, and the outlet of the internal circulation duct 12 extends along the length direction B of the external exhaust and internal circulation range hood.

[0066] In this embodiment, the cross-section of the guide plate 6 is an arc, the center of the arc is located above the axis of the circulating fan 11, the radius of the arc is 155-165mm, the chord length of the arc is 250-255mm, and the chord length of the arc forms an angle of 132-150° with the first side 5 of the external exhaust and internal circulation range hood.

[0067] Specifically, the guide plate 6 is an arc-shaped plate with its opening facing the inlet of the internal circulation duct 12. The center of the arc is located above the axis of the circulating fan 11, along the height direction A of the external and internal circulation range hood. The height difference between the center of the arc and the axis of the circulating fan 11 is 9mm, and the radius of the arc is 160mm. By setting the guide plate 6, the oil fumes can come into contact with the guide plate 6 more smoothly when the inlet of the internal circulation duct 12 is opened, thus avoiding obstruction of the oil fume flow.

[0068] In other embodiments, the cross-section of the guide vane 6 is a straight line. That is, the guide vane 6 is a planar plate.

[0069] Of course, in another embodiment, the cross-section of the deflector 6 can also be other shapes, such as a wavy structure.

[0070] While specific embodiments of this utility model have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of this utility model is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of this utility model, but all such changes and modifications fall within the scope of protection of this utility model.

Claims

1. A range hood with external exhaust and internal circulation, the range hood comprising an internal circulation module, an external exhaust module, a smoke collection hood, and an exhaust pipe, wherein the external exhaust module includes a main fan and an external exhaust duct, and the internal circulation module includes a circulation fan and an internal circulation duct, characterized in that, The inlet of the external exhaust duct is connected to the smoke collection hood, and the outlet of the external exhaust duct is connected to the smoke exhaust pipe. The inlet of the internal circulation duct is connected between the external exhaust duct and the smoke exhaust pipe. Along the height direction of the external and internal circulation range hoods, the internal circulation duct is located above the main fan, the main fan is located inside the external exhaust duct, and the circulation fan is located inside the internal circulation duct. The axis of the main fan is perpendicular to the axis of the circulation fan.

2. The external exhaust and internal circulation range hood as described in claim 1, characterized in that, The external exhaust duct extends along the height direction of the external and internal circulation range hood and is located close to the first side of the external and internal circulation range hood. The internal circulation duct extends along the length direction of the external and internal circulation range hood and its inlet faces the first side of the external and internal circulation range hood. The distance between the inlet of the circulation fan and the first side of the external and internal circulation range hood is n1, where n1 = 1.5 to 1.8L, and L is the length of the main fan along the length direction of the external and internal circulation range hood.

3. The external exhaust and internal circulation range hood as described in claim 2, characterized in that, Along the height direction of the external exhaust and internal circulation range hood, the distance between the axis of the circulation fan and the side wall of the main fan near the exhaust pipe is m1, where m1 = 0.2-0.7D1, and D1 is the inlet diameter of the circulation fan.

4. The external exhaust and internal circulation range hood as described in claim 3, characterized in that, The outlet of the main fan forms an angle of 90-180° with the axis of the circulating fan.

5. The external exhaust and internal circulation range hood as described in claim 4, characterized in that, The exhaust module also includes an air guide duct, which is disposed in the exhaust duct. The first end of the air guide duct is connected to the outlet of the main fan, and the second end of the air guide duct extends into the exhaust duct. The plane of the second end of the air guide duct is parallel to the axis of the circulating fan.

6. The external exhaust and internal circulation range hood as described in claim 5, characterized in that, The side wall of the air duct near the first side of the external exhaust and internal circulation range hood forms an angle of 2-5° with the first side of the external exhaust and internal circulation range hood.

7. The external exhaust and internal circulation range hood as described in claim 1, characterized in that, The internal circulation module also includes a filter section, which is disposed in the internal circulation duct and located between the inlet of the internal circulation duct and the circulation fan. The distance between the side of the filter section facing the circulation fan and the inlet of the circulation fan is greater than or equal to 50 mm.

8. The external exhaust and internal circulation range hood as described in claim 1, characterized in that, A guide plate is also provided at the inlet of the internal circulation duct. The external exhaust and internal circulation range hoods open or close the internal circulation duct through the guide plate. When the guide plate closes the inlet of the internal circulation duct, the circulation fan is turned off. When the guide plate forms a 47° angle with the inlet of the internal circulation duct, the guide plate opens the inlet of the internal circulation duct, and the circulation fan is turned on.

9. The external exhaust and internal circulation range hood as described in claim 8, characterized in that, The cross-section of the guide plate is an arc, the center of the arc is located above the axis of the circulating fan, the radius of the arc is 155-165mm, the chord length of the arc is 250-255mm, and the chord length of the arc forms an angle of 132-150° with the first side of the external exhaust and internal circulation range hood.

10. The external exhaust and internal circulation range hood as described in claim 8, characterized in that, The cross-section of the guide plate is a straight line.

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