Air outlet cover, design method of air outlet cover, fan system and extractor hood

Abstract

The present application relates to air outlet cover, air outlet cover design method, fan system and range hood, air outlet cover includes: first cover body, hollow inside, the first cover body both ends have air inlet and air outlet respectively, the air outlet of the first cover body is used for connecting with exhaust pipe, characterized by further comprising: second cover body, the air inlet of the first cover body is connected, the second cover body extends towards the direction away from the first cover body.Optimal advantage is: using second cover body and lengthening second cover body, the expansion part of air outlet cover and exhaust pipe is hidden in higher and more spacious cabinet, so that range hood can adopt large diameter exhaust pipe, and can be thinned in visible part, therefore, the structure of air outlet cover can be effectively avoided to exceed range hood, the decorative cover of range hood is easy to shield air outlet cover, and the appearance of range hood is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of oil fume purification, and in particular to an air outlet cover, a design method of the air outlet cover, a fan system and a range hood. BACKGROUND

[0002] The range hood is one of the essential kitchen equipment in modern families, and the air outlet cover is an important component of the range hood, which connects the outlet of the fan system and the exhaust pipe, and guides and transports the oil fume to the public flue of the building through the air outlet cover and the exhaust pipe.

[0003] At present, the air outlet cover in the industry usually adopts a square-to-round structure, that is, the cross section of the air inlet of the air outlet cover is rectangular, the cross section of the air outlet of the air outlet cover is circular, the air inlet of the air outlet cover is connected with the outlet of the fan system, and the air outlet of the air outlet cover is connected with the exhaust pipe. In order to reduce the flow loss of the fan and improve the purification effect of the range hood, a kind of air outlet cover, check valve and range hood are disclosed in the Chinese utility model patent with the patent number ZL201920298157.5 (the authorized announcement number is CN209672407U), which comprises a cover body, the air inlet of the cover body is used for communicating with the air outlet pipe of the fan volute, the inner wall of the cover body is provided with a first inclined area, the inner wall of the air outlet pipe of the volute corresponds to the area of the volute tongue, when the cover body communicates with the air outlet pipe of the volute, the first inclined area corresponds to the second inclined area and the inclined directions are consistent.

[0004] Although the above-mentioned air outlet cover can reduce the flow loss of the fan through the first inclined area of the inner wall, the air outlet cover has the following use limitations: when the air outlet cover is applied to the ultra-thin range hood, the first inclined area of the air outlet cover is easy to protrude from the main body of the range hood, so that the decorative cover is difficult to cover the air outlet cover, or even if the decorative cover can cover the air outlet cover, it will protrude from the ultra-thin range hood, which affects the aesthetic appearance of the ultra-thin range hood. Therefore, it is necessary to further improve the prior art. SUMMARY

[0005] The first technical problem to be solved by the present application is to provide an air outlet cover which can effectively avoid protruding from the range hood.

[0006] The second technical problem to be solved by the present application is to provide a design method of the above-mentioned air outlet cover.

[0007] The third technical problem to be solved by the present application is to provide a fan system applying the above-mentioned air outlet cover.

[0008] The fourth technical problem to be solved by the present application is to provide a range hood applying the above-mentioned fan system.

[0009] The present application solves the first technical problem by adopting the technical scheme of a kind of air outlet cover, comprising:

[0010] First cover body, hollow inside, the first cover body two ends have air inlet and air outlet respectively, the air outlet of the first cover body is used to be connected with flue pipe;

[0011] It is characterized by further comprising:

[0012] Second cover body, with the air inlet of the first cover body, the second cover body extends towards the direction away from the first cover body.

[0013] In order to make the air outlet cover have universality, preferably, the cross section of the second cover body is rectangular.

[0014] In order to improve the bending performance of the air outlet cover, the outer peripheral wall of the second cover body is further provided with reinforcing ribs arranged along the extension direction thereof.

[0015] The present application solves the second technical problem by adopting the technical scheme of a kind of design method of the above-mentioned air outlet cover, characterized by comprising:

[0016] The tension F of the air outlet cover received by the flue pipe connected with the air outlet thereof is calculated, and the bending deformation amount ΔL of the air outlet cover is calculated according to the tension F, when the bending deformation amount ΔL / L is less than or equal to the preset threshold n%, it is indicated that the air outlet cover is in the normal elastic deformation range.

[0017] Preferably, the calculation formula of the tension F is:

[0018]

[0019] Wherein, E1 is the elastic modulus of the flue pipe, t1 is the wall thickness of the flue pipe, d2 is the outer diameter of the flue pipe, d1 is the inner diameter of the flue pipe, L is the length of the flue pipe, and v is the poisson's ratio of the flue pipe material.

[0020] Preferably, the calculation formula of the bending deformation amount ΔL of the air outlet cover is:

[0021] ΔL=K*(F*L 3 / (3*E2*I1)

[0022] Wherein, K is the safety factor, L is the height of the air outlet cover, E2 is the elastic modulus of the air outlet cover, and I1 is the cross-sectional moment of inertia of the air outlet cover.

[0023] In the present scheme, the calculation formula of I1 is:

[0024] I1=(A*B 3 ) / 12

[0025] Where A is the length of the air outlet cover and B is the width of the second cover.

[0026] To ensure the safety of the air outlet cover, when the bending deformation ΔL / L is greater than the preset threshold n%, a reinforcing rib extending along its height direction is provided on the outer peripheral wall of the second cover.

[0027] Preferably, the design process of the reinforcing rib is as follows:

[0028] The formula for calculating I1 is:

[0029]

[0030] Where n is the number of reinforcing ribs, t2 is the thickness of the reinforcing ribs, and y is the distance from the reinforcing ribs to the edge of the second cover.

[0031] Set the number and thickness of the reinforcing ribs, and calculate the range of values ​​for y based on ΔL / L≤n%.

[0032] The technical solution adopted by the present invention to solve the third technical problem mentioned above is: a fan system, including a volute, an impeller rotatably disposed in the volute, and an air outlet cover installed at the outlet of the volute, characterized in that: the fan cover adopts the air outlet cover as described above.

[0033] The technical solution adopted by the present invention to solve the fourth technical problem mentioned above is: a range hood, characterized in that: it uses a fan system as described above.

[0034] Compared with the prior art, the advantages of the present invention are as follows: by setting a second cover that connects to the air inlet of the first cover and extending the second cover away from the first cover, the first cover is lengthened by using the second cover, and the expanded part connecting the exhaust hood and the exhaust pipe is hidden in a tall and spacious cabinet, so that the range hood can use a large diameter exhaust pipe and be thinner in the visible part. Therefore, it can effectively prevent the structure of the exhaust hood from exceeding the range hood, making it easy for the decorative cover of the range hood to cover the exhaust hood and improving the aesthetics of the range hood. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the air outlet shroud in Embodiment 1 of the present invention;

[0036] Figure 2 This is a schematic diagram of the air outlet shroud in Embodiment 2 of the present invention;

[0037] Figure 3 for Figure 2 Another perspective structural diagram; Detailed Implementation

[0038] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0039] Example 1:

[0040] This embodiment relates to an exhaust hood, a fan system using the exhaust hood, and a range hood using the fan system. This embodiment also relates to the design method of the aforementioned exhaust hood. The fan system includes a volute (not shown in the figure) and an impeller (not shown in the figure) rotatably disposed within the volute. The exhaust hood is installed at the outlet of the volute. The installation of the fan system and the exhaust hood is prior art in range hoods and will not be elaborated further here.

[0041] The exhaust hood includes a hollow first hood 1 and a hollow second hood 2. The first hood 1 has an air inlet and an air outlet 1b at each end. The air outlet 1b of the first hood 1 is used to connect to a smoke exhaust pipe. The second hood 2 connects to the air inlet of the first hood 1 and extends away from the first hood 1. Figure 1 As shown, in this embodiment, the air outlet 1b of the first cover 1 serves as the outlet of the air outlet hood, and the air inlet of the second cover 2 (the air inlet of the second cover 2 is located on the end face away from the first cover 1) serves as the inlet of the air outlet hood. The air inlet of the second cover 2 is connected to the volute outlet of the range hood.

[0042] In this embodiment, the cross-section of the second cover 2 is the same as the cross-section of the air inlet of the cover 1. In this embodiment, the cross-section of the second cover 2 is rectangular, that is, the second cover 2 is a hollow square tube. The first cover 1 has an inclined area that slopes from the air inlet toward the air outlet 1b. The first cover 1 can be the same as the air outlet hood structure in the prior art. In this embodiment, the air outlet hood is created by lengthening the first cover 1 by extending the second cover 2, thereby hiding the expansion part of the air outlet hood that needs to connect with the exhaust pipe in a tall and spacious cabinet. This allows the fumes to be both covered by a large-diameter exhaust pipe and made thinner in the visible part.

[0043] Range hoods with different structures and installation heights vary. To reduce costs while ensuring bending strength, the design of the exhaust hood aims to use as little material as possible. Since a longer exhaust hood has a larger proportion of hollow rectangle, the risk of bending deformation failure is higher. Conversely, a shorter hood has a lower risk of bending deformation failure. In this embodiment, because... Figure 1 The second hood 2 in the structure accounts for a relatively large proportion. Therefore, to facilitate the estimation of the critical failure size, the exhaust hood is simplified to a hollow cuboid, and its bending deformation can be calculated using the following formula:

[0044] The formula for calculating the bending deformation ΔL of the air outlet hood is:

[0045] ΔL=K*(F*L 3) / (3*E2*I1)

[0046] Where K is the safety factor, L is the height of the air outlet hood, E2 is the elastic modulus of the air outlet hood, and I1 is the moment of inertia of the air outlet hood.

[0047] In this embodiment, K is used to avoid the design risk caused by inaccurate estimation of deformation due to simplified model, and is usually taken as 1.5 to 2; F is the tensile force of the exhaust hood on the smoke exhaust pipe, which is approximately equal to the force required for the lateral tension of the smoke exhaust pipe (corrugated pipe); L represents the height of the exhaust hood, which depends on the distance between its top surface and the cabinet, and is determined by the structure of the range hood, the hanging height, and the height of the cabinet. Since L and L are determined by the preliminary design results, they can be regarded as known quantities in this embodiment; E2 depends on the material of the exhaust hood. The material of the exhaust hood is usually a plastic material with good flame retardant properties and high temperature resistance, such as ABS, PC (polycarbonate) plastic, PP (polypropylene) plastic, and PPS (polyphenylene sulfide) plastic. Taking PP plastic as an example, its elastic modulus is 1000-2000 MPa; I1 is the moment of inertia of the cross section of the exhaust hood. The formula for calculating I1 is: I1=(AB 3 ) / 12, where A is the length of the second cover 2 and B is the width of the second cover 2.

[0048] The formula for calculating the tension F in this embodiment is:

[0049]

[0050] Where E1 is the elastic modulus of the exhaust pipe, t1 is the wall thickness of the exhaust pipe, d2 is the outer diameter of the exhaust pipe, d1 is the inner diameter of the exhaust pipe, L is the length of the exhaust pipe, and ν is the Poisson's ratio of the exhaust pipe material.

[0051] Common materials for exhaust pipes include stainless steel (190-210GPa), galvanized sheet (200-210GPa), and aluminum alloy (70-80GPa). ν represents the Poisson's ratio of the exhaust pipe material; stainless steel is typically between 0.25 and 0.33; galvanized sheet is typically between 0.28 and 0.30; and aluminum alloy is typically between 0.33 and 0.35. t1 is typically between 0.2 and 0.5 mm; d2 is typically between 160 and 180 mm. d1 represents the inner diameter of the exhaust pipe (note that the inner diameter here refers to the inner diameter after the corrugated section is folded, not the inner diameter equal to the outer diameter minus the wall thickness), which depends on the outer diameter and is usually the outer diameter minus 20-30 mm. L represents the length of the corrugated pipe; the length of a household range hood exhaust pipe is usually no more than 3000 mm.

[0052] The exhaust hood design method in this embodiment includes: calculating the tensile force F exerted on the exhaust hood by the smoke exhaust pipe connected to its exhaust outlet, and calculating the bending deformation ΔL of the exhaust hood based on the tensile force F. When the bending deformation ΔL / L is less than or equal to a preset threshold n%, it indicates that the exhaust hood is within the normal elastic deformation range and no additional reinforcing ribs are needed. In this embodiment, n% = 5%.

[0053] Example 2:

[0054] like Figure 2 and Figure 3 As shown, unlike Embodiment 1, the bending resistance of the extended exhaust hood decreases. Furthermore, when installing the range hood, the force applied to the exhaust hood by the exhaust pipe is not perpendicular to the ground but parallel to it. When the extended exhaust hood is applied to a range hood, a force will obviously be applied to the part of the exhaust hood furthest from the fixed end of the exhaust pipe when the exhaust pipe is tensioned, creating torque. The longer the exhaust pipe, the greater the risk of bending deformation and the lower the reliability. To solve the above technical problems, the outer peripheral wall of the second hood 2 in this embodiment is also provided with reinforcing ribs 21 arranged along its extension direction. By providing reinforcing ribs 21 on the second hood 2, the bending resistance of the exhaust hood can be improved.

[0055] When the bending deformation ΔL / L in Embodiment 1 is greater than the preset threshold n%, a reinforcing rib 21 extending along its height direction is provided on the outer peripheral wall of the second cover 2. After the reinforcing rib 21 is provided on the second cover 2, the calculation formula for I1 becomes:

[0056] Where n is the number of reinforcing ribs 21, t2 is the thickness of the reinforcing ribs 21, and y is the distance from the reinforcing ribs 21 to the edge of the second cover 2.

[0057] In this embodiment, the reinforcing ribs 21 are symmetrically distributed on the two opposite outer walls of the second cover 2, and n is preferably 2 to 6; usually, because the thickness of the heating ribs (plastic material) is too large, it is easy to deform and crack during processing, so t2 should not exceed 5mm.

[0058] The specific design process of the reinforcing rib 21 is as follows: set the number and thickness of the reinforcing rib 21, and calculate the range of values ​​for y based on ΔL / L≤n%.

[0059] In this embodiment, L is the height of the air outlet hood (excluding the reinforcing ribs) (i.e. Figure 3 The length in the X direction), A is the length of the second cover 2 (excluding the reinforcing ribs) (i.e. Figure 3 B is the length in the Z direction, and B is the width of the second cover 2 (excluding the reinforcing ribs). Figure 3 (Length in the Y direction).

Claims

1. An air outlet cover, comprising: a first cover body (1) which is hollow inside, the first cover body (1) having an air inlet and an air outlet (1b) at two ends respectively, the air outlet (1b) of the first cover body (1) being used for connecting with a smoke exhaust pipe; characterized in that it further comprises: a second cover body (2) which is connected with the air inlet of the first cover body (1), the second cover body (2) extending towards a direction away from the first cover body (1); the cross section of the second cover body (2) is rectangular, i.e. the second cover body (2) is a square tube which is hollow inside, the first cover body (1) has an inclined area which is inclined from the air inlet towards the air outlet (1b), the air outlet cover is lengthened by the second cover body (2) and the first cover body (1), so that the expansion part of the air outlet cover connected with the smoke exhaust pipe is hidden in a cabinet which is higher and has more space.

2. The air deflector of claim 1, wherein: The outer peripheral wall of the second cover body (2) is further provided with a reinforcing rib (21) which is arranged along the extension direction thereof.

3. A method of designing an air outlet casing according to claim 1, characterized in that comprising: calculating the pulling force F of the air outlet cover which is caused by the smoke exhaust pipe connected with the air outlet thereof, and calculating the bending deformation amount AL of the air outlet cover according to the pulling force F, when the bending deformation amount AL / L is less than or equal to a preset threshold n%, it is indicated that the air outlet cover is in a normal elastic deformation range.

4. The method of designing according to claim 3, characterized in that: The calculation formula of the pulling force F is: wherein E1 is the elastic modulus of the smoke exhaust pipe, t1 is the wall thickness of the smoke exhaust pipe, d2 is the outer diameter of the smoke exhaust pipe, d1 is the inner diameter of the smoke exhaust pipe, L is the length of the smoke exhaust pipe, and v is the Poisson's ratio of the material of the smoke exhaust pipe.

5. The method of designing according to claim 4, characterized in that: The calculation formula of the bending deformation amount AL of the air outlet cover is: ΔL = K * (F * L 3 ) / (3 * E2 * I1) wherein K is a safety factor, L is the height of the air outlet cover, E2 is the elastic modulus of the air outlet cover, and I1 is the cross-sectional moment of inertia of the air outlet cover.

6. The method of designing according to claim 5, characterized in that: The calculation formula of I1 is: I1 = (A * B 3 ) / 12 wherein A is the length of the air outlet cover, and B is the width of the second cover body (2).

7. The method of claim 5, wherein: When the bending deformation amount AL / L is greater than the preset threshold n%, the reinforcing rib (21) which extends along the height direction of the outer peripheral wall of the second cover body (2) is arranged.

8. The method of designing according to claim 7, characterized in that: The design process of the reinforcing rib (21) is: The calculation formula of I1 is: wherein n is the number of the reinforcing rib (21), t2 is the thickness of the reinforcing rib (21), and y is the distance from the reinforcing rib (21) to the edge of the second cover body (2); The number of the reinforcing rib (21) and the thickness of the reinforcing rib (21) are set, and the value range of y is calculated according to AL / L≤n%.

9. A fan system comprising a volute, an impeller rotatably disposed within the volute, and a fan cover mounted at an outlet of the volute, characterized in that: The air outlet cover adopts the air outlet cover according to the above claim 1 or 2.

10. A range hood characterized by: The fan system has the air outlet cover according to the above claim 9.

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