Methods for drawing volute profiles, check valve profiles, air duct structures, and range hoods

Abstract

The present invention relates to the technical field of range hood design, and specifically to a method for drawing a volute profile, a method for drawing a check valve profile, an air duct structure, and a range hood. The method for drawing a volute profile provided by the present invention is based on a first volute profile generated by a logarithmic spiral, gradually increases the opening degree of the first spiral segment by region, and then refits it into a second spiral segment, and fits the second spiral segment with the first straight line segment, the second straight line segment, the volute tongue profile, and the third straight line segment of the first volute profile into the final second volute profile; compared with the existing volute profile generation method, the volute profile drawing method provided by the present application retains the advantages of the logarithmic spiral, and can also conveniently and quickly perform local corrections on the volute profile according to the limiting conditions, so that the volute profile increases evenly without mutations, and finally makes the airflow acceleration in the volute more uniform and stable, reduces pressure pulsation, and reduces aerodynamic noise.

Description

Technical Field

[0001] The invention relates to the technical field of range hood design, and in particular to a method for drawing a volute profile, a method for drawing a check valve profile, an air duct structure and a range hood. Background Art

[0002] The air duct system of a household range hood is mainly composed of a volute assembly, an impeller, a motor assembly, and a check valve. The volute and the check valve provide a flow channel for the gas; the volute guides the gas leaving the impeller to the volute outlet and converts part of the dynamic pressure into static pressure. The flow in the volute is very complex. While the gas flows along the volute, there is a constant flow of gas from the impeller into the volute, that is, the gas mixes while flowing. Therefore, the design of the volute profile directly determines the aerodynamic performance of the fan, and then determines the aerodynamic performance and noise performance of the range hood.

[0003] Currently, the design of volute profiles usually adopts the four-segment arc method and the logarithmic spiral method.

[0004] like Figure 1 As shown in the figure, the four-segment circular arc method uses four circular arcs to draw the volute profile. The selection of its parameters often relies on a lot of experience accumulation, and the drawing process is cumbersome. If the width and height of the volute change, it is necessary to change the sizes of the four circular arcs at the same time, and local correction is extremely difficult, resulting in discontinuous curves and cumbersome generation.

[0005] like Figure 2 As shown in the figure, the volute profile generated by the logarithmic spiral is generated by a curve of a single equation. If the volute width and height dimensions change, it is only necessary to correct the R coefficient in the equation to obtain the correction of the entire curve, but there is also a defect that local correction cannot be performed. Summary of the invention

[0006] (I) The technical problem to be solved by the present invention is that in the current volute profile design, if the width and height dimensions of the volute change, it is difficult to partially modify the volute profile.

[0007] (II) Technical solution

[0008] In order to solve the above technical problems, an embodiment of the present invention provides a method for drawing a volute profile, comprising:

[0009] The impeller radius R1 is selected according to the width W1 of the casing and the height H1 of the casing, and the first profile of the volute is formed according to the logarithmic spiral equation;

[0010] The first profile of the volute includes a first straight line segment, a second straight line segment, a volute tongue profile, a first spiral line segment and a third straight line segment connected in sequence;

[0011] The first spiral segment is divided into N parts with equal angles by N+1 rays starting from the origin O of the logarithmic spiral, and a circle is drawn with O as the center and R1 as the radius to form an impeller profile;

[0012] The distance between the intersection point of each ray with the impeller profile and the intersection point of the ray with the first spiral line segment is the opening degree of the ray, and the difference in the opening degree between two adjacent rays along the extension direction of the first spiral line segment is a constant value;

[0013] Taking the impeller profile as a reference and according to a preset opening difference, the intersection position of each ray and the first profile of the volute is corrected, and the N corrected intersection points are sequentially fitted to form a new second spiral line segment; the first straight line segment, the second straight line segment, the volute tongue profile, the second spiral line segment and the third straight line segment connected in sequence constitute the second profile of the volute.

[0014] According to one embodiment of the present invention, the first spiral line segment includes a first segment and a second segment, and the volute tongue profile is connected to the second segment through the first segment;

[0015] The second segment includes a first arc segment and a second arc segment, the first arc segment has a starting point Z and an end point K, and the second arc segment has a starting point K and an end point U;

[0016] The difference in the opening degrees corresponding to two adjacent rays on the first arc segment is preset to be y, and along the direction from the starting point to the end point of the first arc segment, the intersection position of each ray corresponding to the first arc segment and the first profile line of the volute is sequentially corrected according to the difference y with the starting point Z as the reference;

[0017] The difference in the opening degrees corresponding to two adjacent rays of the second arc segment is preset to be x, and along the direction from the end point to the starting point of the second arc segment, the intersection position of each ray corresponding to the second arc segment and the first profile line of the volute is sequentially corrected according to the difference x with the starting point U as a reference;

[0018] According to the above method, until the corrected K point position of the first arc segment and the corrected K point position of the second arc segment meet the fitting condition, all the corrected intersection points from point Z to point U are refitted to form a second spiral segment.

[0019] According to an embodiment of the present invention, a point E is formed on the first arc segment, and the angle between any two adjacent rays on the first arc segment is ∠ZOE;

[0020] A point T is formed on the second arc segment, the angle between any two adjacent rays on the second arc segment is ∠UOT=α1, the line segment ET is a horizontal line passing through the origin O, and the line segment OK is a vertical line.

[0021] According to one embodiment of the present invention, the impeller radius R1 is selected according to the width W1 of the chassis and the height H1 of the chassis, and the first profile of the volute is formed according to the logarithmic spiral equation, including:

[0022] The first spiral segment is generated according to the cylindrical coordinate equation of the logarithmic spiral R=R1*exp(ζ*t), wherein point T1 is the starting point of the logarithmic spiral, and the logarithmic spiral goes through an angle of 360+α1, at which point U is the end point of the logarithmic spiral;

[0023] The angle between the third straight line segment and the vertical line passing through the origin O is α3. Since the height H1 of the chassis, the position of the point U and the angle α3 are all preset values, the position of the end point A of the third straight line segment can be determined;

[0024] The length L0 of the first straight line segment is the width of the volute air outlet, which is a preset value, and the first straight line segment is a horizontal straight line, so the position of the end point B of the first straight line segment can be obtained;

[0025] The angle between the second straight line segment and the vertical line passing through the origin O is α2, the distance between the center of the volute tongue profile and the vertical line passing through the origin O is W2, W2 and α2 are preset values, and the volute tongue profile is tangent to the second straight line segment and the first spiral line segment respectively, and the starting point C and the end point D of the volute profile can be obtained;

[0026] The first straight line segment, the second straight line segment, the volute tongue profile, the first spiral line segment and the third straight line segment connected in sequence constitute the first profile of the volute.

[0027] According to one embodiment of the present invention, 45°>α2>α3>0°, α1≤15°.

[0028] According to one embodiment of the present invention, the length of line segment ET is less than or equal to W1.

[0029] Another aspect of the present invention is to provide a method for drawing a check valve profile, comprising: generating a check valve profile based on a second volute profile obtained by the method for drawing a volute profile according to any of the above embodiments.

[0030] According to one embodiment of the present invention, generating a check valve profile based on the second profile of the volute includes:

[0031] Rotate α4 degrees with the starting point of the first straight line segment as the center;

[0032] The check valve profile includes a fourth straight line segment, a first arc segment, a fifth straight line segment and a second arc segment connected in sequence, and the fifth straight line segment overlaps with the first straight line segment;

[0033] The starting point of the fourth straight line segment is V and the end point is W. The length of the fourth straight line segment is determined according to the diameter of the exhaust pipe;

[0034] The height of the check valve is H2, and the diameter of the first arc segment is R a , the diameter of the second arc segment is R b； The check valve profile is generated according to the length of the fourth straight line segment, the diameter of the first arc segment, the diameter of the second arc segment and the position of point A.

[0035] According to one embodiment of the present invention, generating the check valve profile according to the length of the fourth straight line segment, the diameter of the first arc segment, the diameter of the second arc segment, and the position of point A comprises:

[0036] Draw a horizontal line L0, the distance between point A and L0 is equal to H2;

[0037] With point A as the center and R b Draw a circle with radius L0 and locate O1 at the intersection point. Take O1 as the center and R as the center. b The intersection point of a circle with a radius of L0 and L0 is the starting point V of the fourth straight line segment, and a second curve is determined;

[0038] Determine the length VW according to the diameter of the discharge pipe, and then determine the position of the end point W of the fourth straight line segment, and determine the fourth straight line segment;

[0039] With point B as the center and R a Draw a circle with radius L0 and locate O2 at the intersection point. Take O2 as the center and R as the center. a A circle is drawn with the radius to obtain a second arc segment, and the fourth straight line segment, the first arc segment, the fifth straight line segment, and the second arc segment connected in sequence constitute a check valve profile.

[0040] Another embodiment of the present invention further provides an air duct structure, including a check valve and a volute, wherein the volute is made according to the second volute profile provided in the above implementation, and the check valve is made according to the check valve profile provided in the above embodiment.

[0041] Another aspect of the present invention provides a range hood including the air duct structure provided in the above embodiment.

[0042] Beneficial effects of the present invention: The method for drawing the volute profile provided by the present invention includes selecting the impeller radius R1 according to the width W1 of the chassis and the height H1 of the chassis, and forming the first profile of the volute according to the logarithmic spiral equation, wherein the first profile of the volute includes a first straight line segment, a second straight line segment, a volute tongue profile, a first spiral line segment and a third straight line segment connected in sequence; then, according to a preset opening difference, taking the impeller profile as a reference, correcting the position of the point on the first spiral line segment, fitting N corrected intersection points in sequence to form a second spiral line segment, and the first straight line segment, the second straight line segment, the volute tongue profile, the second spiral line segment and the third straight line segment connected in sequence constitute the second profile of the volute.

[0043] The method for drawing the volute profile provided in the present application is based on the first volute profile generated by a logarithmic spiral line, gradually and equally increases the opening degree of the first spiral line segment according to the region, and then re-fits it into a second spiral line segment, and fits the second spiral line segment with the first straight line segment, the second straight line segment, the volute tongue profile line and the third straight line segment of the first volute profile line into the final second volute profile line, and re-adapts the opening degree of the local area to make it increase evenly without sudden changes, thereby ultimately making the airflow acceleration in the volute more even and stable, reducing pressure pulsation, and reducing aerodynamic noise; compared with the existing volute profile generation method, the method for drawing the volute profile provided in the present application retains the advantages of the logarithmic spiral, and can also conveniently and quickly perform local corrections on the volute profile line according to the restriction conditions, so that the volute profile line increases evenly without sudden changes. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0045] Figure 1 The volute profile is drawn using the existing four-segment arc method;

[0046] Figure 2 The volute profile drawn for the existing logarithmic spiral method;

[0047] Figure 3 A schematic diagram of a volute profile drawn by a volute profile drawing method is provided for one embodiment of the present invention;

[0048] Figure 4 A schematic diagram of a volute profile drawn by a volute profile drawing method is provided for another embodiment of the present invention;

[0049] Figure 5 A schematic diagram of the cooperation between the volute profile and the check valve profile provided in one embodiment of the present invention;

[0050] Figure 6 A schematic diagram of a check valve profile provided by an embodiment of the present invention;

[0051] Figure 7 A schematic diagram of a range hood provided in accordance with an embodiment of the present invention.

[0052] Icons: 1-volute; 11-front cover; 12-first volute line; 121-first straight line segment; 122-second straight line segment; 123-volute tongue line; 124-first spiral line segment; 1241-first segment; 1242-second segment; 12421-first arc segment; 12422-second arc segment; 125-third straight line segment;

[0053] 13- second profile line of volute; 131- second spiral line segment;

[0054] 2-check valve profile; 21-fourth straight line segment; 22-first arc segment; 23-second arc segment;

[0055] 3-range hood; 31-chassis. DETAILED DESCRIPTION

[0056] In order to more clearly understand the above-mentioned purposes, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present invention.

[0057] According to one embodiment of the present invention, Figures 3 to 5 As shown, the present invention provides a method for drawing a volute profile, comprising: selecting an impeller radius R1 according to a width W1 of a case 31 and a height H1 of the case 31, and forming a first volute profile 12 according to a logarithmic spiral equation; the first volute profile 12 comprises a first straight line segment 121, a second straight line segment 122, a volute tongue profile 123, a first spiral line segment 124 and a third straight line segment 125 connected in sequence; N+1 rays starting from an origin O of the logarithmic spiral divide the first spiral line segment 124 into N parts at equal angles, and a circle is drawn with O as the center and R1 as the radius to form an impeller profile; each ray and the impeller profile are connected to each other. The distance between the intersection of the line and the intersection of the ray and the first spiral segment 124 is the opening of the ray. Along the extension direction of the first spiral segment 124, the difference in opening between two adjacent rays is a constant. Taking the impeller profile as a reference and according to the preset opening difference, the intersection position of each ray and the first volute profile 12 is corrected, and the N corrected intersections are sequentially fitted to form a new second spiral segment 131. The first straight line segment 121, the second straight line segment 122, the volute tongue profile 123, the second spiral segment 131 and the third straight line segment 125 connected in sequence constitute the volute second profile 13.

[0058] In the volute profile, the middle curve is the most critical part of the entire volute profile. However, the volute profile generated by the existing logarithmic spiral is generated by a curve of a single equation. When the width and height of the volute 1 change, the R coefficient in the equation can be corrected to obtain the correction of the entire curve. However, the curve cannot be corrected locally, so there will be local sudden changes and discontinuities in the curve. The volute profile drawing method provided in this embodiment selects the impeller radius R1 according to the width W1 of the chassis 31 and the height H1 of the chassis 31, wherein the impeller radius has a fixed model. When generating the volute profile, a suitable impeller radius is selected according to the height and width of the chassis 31, and then the first volute profile 12 is formed according to the logarithmic spiral equation; and then the first spiral segment 124 in the middle part of the first volute profile 12 is corrected. Specifically, the opening degree is gradually and equally increased in the first spiral segment 124 in sequence according to the area, and the points of the first spiral segment 124 that are re-corrected are sequentially fitted to form the second spiral segment 131. Since the line types of the first straight segment 121, the second straight segment 122, the volute tongue profile 123 and the third straight segment 125 have not changed, the second spiral segment 131 and the first straight segment 121, the second straight segment 122, the volute tongue profile 123 and the third straight segment 125 of the first volute profile 12 are fitted into the final volute second profile 13; since the first spiral segment 124 is corrected in a manner of increasing the opening degree in equal values, the line type of the re-corrected second spiral segment 131 increases uniformly without mutation; and compared with the existing method of generating volute profiles by logarithmic spirals, the volute second profile 13 generated by the volute profile drawing method provided in this embodiment can be locally corrected, so the line type is smoother, and ultimately the airflow acceleration in the volute 1 is more uniform and stable, the pressure pulsation is reduced, and the aerodynamic noise is reduced.

[0059] like Figure 3 and Figure 5 As shown, in this embodiment, the chassis 31 is a shell for mounting the volute 1 , so the width W1 of the chassis 31 is greater than the maximum width of the volute 1 , and the height H1 of the chassis 31 is greater than the maximum height of the volute 1 .

[0060] According to one embodiment of the present invention, Figure 3 and Figure 4As shown, the first spiral line segment 124 includes a first segment 1241 and a second segment 1242, and the volute tongue profile 123 is connected to the second segment 1242 through the first segment 1241; wherein the first segment 1241 is connected to the volute tongue profile 123 and is located in the upper half of the volute 1, and even if its line shape is not corrected, the aerodynamic performance of the fan is very small, so the first segment 1241 of the first spiral line does not participate in the correction, and only the second segment 1242 of the first spiral line located in the lower half of the volute profile is partially corrected. Of course, in this embodiment, the entire first spiral line segment 124 can also be corrected, which can also achieve the purpose of the present invention.

[0061] The second segment 1242 includes a first arc segment 12421 and a second arc segment 12422, wherein the starting point of the first arc segment 12421 is Z and the end point is K, and the starting point of the second arc segment 12422 is K and the end point is U. In this embodiment, the second segment 1242 of the first spiral segment 124 is divided into a first arc segment 12421 and a second arc segment 12422, and then the second arc segment 12422 and the first arc segment 12421 are respectively corrected according to the method of increasing the opening degree by equal values, which can ensure that the corrected line type is smooth and without mutations, and the sum of the number of rays equally divided by the first arc segment 12421 and the number of rays equally divided by the second arc segment 12422 is N+1.

[0062] According to one embodiment of the present invention, Figures 3 to 5 As shown, the starting point of the first arc segment 12421 is Z and the end point is K, the starting point of the second arc segment 12422 is K and the end point is U, the difference in the opening corresponding to two adjacent rays on the first arc segment 12421 is preset to be y, and along the direction from the starting point to the end point of the first arc segment 12421, the intersection position of each ray corresponding to the first arc segment 12421 and the first profile line 12 of the volute is sequentially corrected according to the difference y with the starting point Z as the reference; Figure 3As shown, in this embodiment, the first arc segment 12421 is equally divided into eight rays, that is, counting the starting point Z and the end point K of the first arc segment 12421, there are six intersection points between point Z and point K, and the directions from Z to K are point E, point F, point G, point H, point I and point J in sequence. The corresponding line segments of the eight rays are OZ, OE, OF, OG, OH, OI, OJ and OK, respectively. The angles between two adjacent line segments are all equal. At the same time, the intersections of OZ, OE, OF, OG, OH, OI, OJ and OK with the impeller profile are The points are Z1, E1, F1, G1, H1, I1, J1 and K1. Assuming the length of line segment ZZ1 is L18, the length of line segment EE1 is L1, the length of line segment FF1 is L2, the length of line segment GG1 is L3, the length of line segment HH1 is L4, the length of line segment II1 is L5, the length of line segment JJ1 is L6, and the length of line segment KK1 is L7, then L18-L1=L1-L2=L2-L3=L3-L4=L4-L5=L5-L6=L6-L7=y. Figure 3 and Figure 5 As shown, points F, G, H, I, J and K on the first arc segment 12421 are adjusted according to the above principle.

[0063] Similarly Figure 3 and Figure 4 As shown, the correction of the second arc segment 12422 is the same as the above embodiment, and the difference in the opening degrees corresponding to two adjacent rays on the second arc segment 12422 is preset to be x, and along the direction from the starting point to the end point of the second arc segment 12422, the intersection position of each ray corresponding to the second arc segment 12422 and the first profile line 12 of the volute is corrected in sequence according to the difference x with the starting point U as the reference; Figure 3 and Figure 5 As shown, in this embodiment, the second arc segment 12422 is equally divided into eight rays, that is, counting the starting point K and the end point U of the second arc segment 12422, there are six intersection points between point U and point K, and the directions from U to K are point T, point S, point Q, point P, point N and point M in sequence, and the corresponding line segments of the eight rays are OU, OT, OS, OQ, OP, ON, OM and OK respectively, and the angles between two adjacent line segments are equal. At the same time, OU, OT, OS, The intersection points of OQ, OP, ON, OM and OK with the impeller profile are U1, T1, S1, Q1, P1, N1, M1 and K1 respectively. Assume that the length of line segment UU1 is L14, the length of line segment TT1 is L13, the length of line segment SS1 is L12, the length of line segment QQ1 is L11, the length of line segment PP1 is L10, the length of line segment NN1 is L9, the length of line segment MM1 is L8 and the length of line segment KK1 is L7.

[0064] Then L14-L13=L13-L12=L12-L11=L11-L10=L10-L9=L9-L8=L8-L7=x. Figure 3 and Figure 5 As shown, points S, Q, P, N, M and K on the second arc segment 12422 are adjusted according to the above principle. Preferably, in this embodiment, the correction value y of the first arc segment 12421 is equal to the correction value x of the second arc segment 12422.

[0065] in Figure 3 and Figure 5 As shown, the solid line portion in this embodiment is the first spiral segment 124 before correction, and the dotted line portion is the second spiral segment 131 after correction; Figure 3 and Figure 5 The number of corrected intersections is only for illustration, wherein the number of corrected points in the first arc segment 12421 and the second arc segment 12422 may be the same or different, and the number of corrected intersections is not limited to the number in the above-mentioned embodiments; the angles equally divided on the first arc segment 12421 and the second arc segment 12422 may be the same or different, for example, ∠ZOE≠∠UOT, or ∠ZOE=∠UOT, and the correction values ​​of the first arc segment 12421 and the second arc segment 12422 may also be different.

[0066] Preferably, Figure 3 and Figure 5 As shown, in this embodiment, the preset point T1 is the starting point of the logarithmic spiral, the length of the line segment OT1 is equal to the impeller radius R1, point U is the end point of the logarithmic spiral (also the end point of the second arc segment 12422), and OU deviates from OT by an angle α1, that is, the logarithmic spiral passes through an angle of 360+α1, where α1 is also the angle equally divided by the second arc segment 12422. In the correction process of the above embodiment of the present application, since L18-L1=y and L14-L13=x are all reference values, that is, point Z, point E, point U and point T are all reference values ​​and do not need to be corrected.

[0067] Since the first arc segment 12421 and the second arc segment 12422 of the first spiral segment 124 are corrected separately, the K point corrected according to the first arc segment 12421 may be different from the K point corrected according to the second arc segment 12422. At this time, it is necessary to adjust the correction coefficients x and y, and finally make the corrected K points of the first arc segment 12421 and the second arc segment 12422 coincide or be close to each other. At this time, the fitting condition is met, and the corrected points on the first arc segment 12421 and the second arc segment 12422 are fitted and connected with the first segment 1241 of the first spiral segment 124 to form the second spiral segment 131. The second spiral segment 131 is fitted with the unchanged first straight line segment 121, the second straight line segment 122, the volute tongue profile 123 and the third straight line segment 125 on the first profile 12 of the volute to form the corrected second profile 13 of the volute.

[0068] Preferably, Figure 3 and Figure 5 As shown, line segment ET is a horizontal straight line passing through the origin O, and line segment OK is a vertical straight line, so the length of ET is less than W1.

[0069] According to one embodiment of the present invention, Figure 3 and Figure 5 As shown, the impeller radius R1 is selected according to the width W1 of the case 31 and the height H1 of the case 31, and the first profile line 12 of the volute is formed according to the logarithmic spiral equation, including: generating a first spiral segment 124 according to the cylindrical coordinate equation R=R1*exp(ζ*t) of the logarithmic spiral, wherein point T1 is the starting point of the logarithmic spiral, and the logarithmic spiral passes through an angle of 360+α1, at which point U is the end point of the logarithmic spiral, wherein ζ is a coefficient, usually ζ=0.6, t is an angle, and R1 is the impeller radius. The angle between the third straight line segment 125 and the vertical line passing through the origin O is α3. Since the height H1 of the chassis 31, the position of the point U and the angle α3 are all preset values, the position of the end point A of the third straight line segment 125 can be determined; the length L0 of the first straight line segment 121 is the preset value of the width of the air outlet of the volute 1, and the first straight line segment 121 is a horizontal straight line, so the position of the end point B of the first straight line segment 121 can be obtained; the angle between the second straight line segment 122 and the vertical line passing through the origin O is α2, the distance between the center of the volute tongue profile 123 and the vertical line passing through the origin O is W2, W2 and α2 are preset values, and the volute tongue profile 123 is tangent to the second straight line segment 122 and the first spiral line segment 124 respectively, so the starting point C and the end point D of the volute profile can be obtained; the first straight line segment 121, the second straight line segment 122, the volute tongue profile 123, the first spiral line segment 124 and the third straight line segment 125 connected in sequence constitute the first volute profile 12. Preferably, in this embodiment, 45°>α2>α3>0°, and α1≤15°.

[0070] An embodiment of the present invention further provides a volute 1, the volute 1 includes a front cover plate 11, a rear cover plate, and an annular wall disposed between the front cover plate 11 and the rear cover plate, and the inner contour line of the annular wall is constructed by the second volute profile 13 drawn according to the method provided in the above embodiment of the present application. Since the inner wall contour line of the volute 1 provided by the present invention can be partially modified, the inner profile line of the volute 1 is smoother and more coherent, making the airflow acceleration flow channel more stable and smooth, and finally making the airflow acceleration in the volute 1 more uniform and stable, reducing pressure pulsation, and reducing aerodynamic noise.

[0071] Another embodiment of the present invention provides a method for drawing a check valve profile 2, which generates a check valve profile 2 based on the second volute profile 13 generated in the above embodiment. The traditional check valve is a simple square-to-circle structure, which is not designed in any way related to the volute profile, causing the airflow to be forced to turn and impact in the check valve, resulting in a sharp loss of performance. Figure 5 and Figure 6 As shown, the check valve profile 2 generated by the check valve profile 2 drawing method provided in the present application is adapted to the second volute profile design, and the airflow coming out of the volute 1 and entering the check valve also flows along the profile without sudden changes and is integrated into one, so that the airflow runs faster and more smoothly, and can reduce noise and improve aerodynamic performance. The check valve profile 2 of the present invention is simultaneously given in the design of the volute profile, and a design method is given in combination with the installation space, height, expansion, etc., so that the check valve can be well matched with the volute 1 and the exhaust duct from the bottom inlet to the top plate outlet.

[0072] Preferably, in this embodiment, the check valve profile 2 is generated based on the second profile 13 of the volute, including: rotating the second profile 13 of the volute by α4 degrees with the starting point of the first straight line segment 121 as the center; the check valve profile 2 includes a fourth straight line segment 21, a first arc segment 22, a fifth straight line segment and a second arc segment 23 connected in sequence, and the fifth straight line segment and the first straight line segment 121 overlap; the starting point of the fourth straight line segment 21 is V, the end point is W, and the length of the fourth straight line segment 21 is determined according to the diameter of the exhaust pipe; the height of the check valve is H2, and the diameter of the first arc segment 22 is R a , the diameter of the second arc segment 23 is R b； The check valve profile 2 is generated according to the length of the fourth straight line segment 21 , the diameter of the first arc segment 22 , the diameter of the second arc segment 23 , and the position of point A.

[0073] Since the width of the case 31 in the present application is limited, and the entire second mold line 13 of the volute needs to be rotated α4 degrees, the distance from the side wall of the case 31 to the starting point V of the fourth straight line segment 21 can be determined based on the width W1 of the case 31 and the rotation angle α4 of the second mold line 13 of the volute, that is, a vertical line is drawn through V, and the distance between the vertical line and the side wall of the case 31 is L16. At the same time, the distance between the vertical line corresponding to the starting point A of the first straight line segment 121 and the vertical line corresponding to V is L15. Since the rotation angle α4 is known and the width W1 of the case 31 is known, the numerical range of L16 can be determined, and then the numerical range of L15 can be determined; since the installation height of the whole machine is limited to a certain extent, the height H2 of the check valve can be determined. At this time, a horizontal line L0 is drawn, and the distance between point A and L0 is equal to H2; with point A as the center and R as the center, b Draw a circle with radius L0 and locate O1 at the intersection point. Take O1 as the center and R as the center. b The intersection point of the circle with radius L0 and L0 is taken as the starting point V of the fourth straight line segment, and the second curve is determined. The point V has a component only in the vertical direction (or close to the vertical direction).

[0074] Since the discharge pipe needs to be based on the internationally recommended exhaust pipe diameter, when designing the check valve profile, an exhaust pipe with a suitable diameter is selected according to the height of the check valve and the information of the volute profile. The diameter of the exhaust pipe is equal to the length of the fourth straight line segment 21, and then the position of the end point W of the fourth straight line segment 21 is determined, and the line shape of the fourth straight line segment 21 is determined;

[0075] With point B as the center and R a Locate O2 at the intersection of the circle with radius L0, where R a The fixed value needs to be selected according to the different exhaust pipe diameters. a A second arc segment 23 is obtained by drawing a circle with the radius, and at point W has only (or close to) a vertical component. The fourth straight line segment 21, the first arc segment 22, the fifth straight line segment, and the second arc segment 23 connected in sequence constitute the check valve profile 2.

[0076] In this embodiment, the first arc segment 22 and the second arc segment 23 are designed to match the volute profile. At the same time, the check valve formed by the second arc segment 23 and the first arc segment 22 has a structure that gradually increases from the lower port AB to the outlet VW, so that the airflow at the outlet of the volute 1 is well diffused in this interval. When the airflow passes through the diffuser (check valve), due to the continuous expansion of the channel area, part of the kinetic energy is converted into static pressure energy, thereby improving the static pressure and efficiency of the fan system and reducing the dynamic pressure loss at the outlet.

[0077] In one aspect, an embodiment of the present invention further provides a check valve, such as Figure 5 and Figure 6As shown, the check valve includes an outer plate, an inner plate, a front plate and a rear plate; the outer plate, the inner plate, the front plate and the rear plate are connected to form a smoke exhaust channel with a smoke inlet and a smoke exhaust port, wherein the outer plate, the inner plate and the upper edge of the check valve and the lower edge of the check valve are prepared according to the check valve profile 2 described in the above embodiment, the inner wall contour of the outer plate is a first arc segment 22, and the inner wall contour of the inner plate is a second arc segment 23. The check valve provided in the present application is adapted to the design of the volute 1, and the airflow from the volute 1 to the check valve also flows along the profile, without sudden changes, and is integrated. At the same time, the smoke exhaust channel inside the check valve gradually increases from bottom to top, so that the airflow at the outlet of the volute 1 is well diffused in this interval. When the airflow passes through the diffuser (check valve), due to the continuous expansion of the channel area, part of the kinetic energy is converted into static pressure energy, thereby improving the static pressure and efficiency of the fan system and reducing the dynamic pressure loss at the outlet.

[0078] Another embodiment of the present invention further provides an air duct system, including a check valve and a volute 1 prepared according to the above embodiment, wherein the check valve is installed on the volute 1. The air duct system provided by this embodiment can improve the static pressure and efficiency of the fan system and reduce the dynamic pressure loss at the outlet because the internal contour of the volute 1 can be partially modified and the contour of the check valve is drawn according to the contour of the volute 1.

[0079] like Figure 7 As shown, the present invention also provides a range hood 3 including the air duct system provided in the above embodiment. It is installed in the chassis 31 to form a complete range hood 3. The range hood 3 provided in this embodiment has improved aerodynamic performance, reduced noise, and sufficient check valve installation space is reserved in advance. The check valve contour line of the present invention is synchronously given in the design of the volute profile line, and the design method is given in combination with the installation space, height, expansion, etc., so that the check valve can be well matched with the volute 1 and the exhaust pipe from the bottom inlet to the top plate outlet, and has a structure of small bottom and large top, and synchronously has the function of a diffuser.

[0080] In the description of the present invention, it should be noted that the terms "upper", "lower", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0081] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the inside of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. In addition, in the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0082] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for drawing a volute profile, characterized in that: include: The impeller radius R1 is selected according to the width W1 of the casing (31) and the height H1 of the casing (31), and the first volute profile (12) is formed according to the logarithmic spiral equation; The first volute profile (12) comprises a first straight line segment (121), a second straight line segment (122), a volute tongue profile (123), a first spiral line segment (124) and a third straight line segment (125) which are connected in sequence; The first spiral line segment (124) is divided into N parts at equal angles by N+1 rays starting from the origin O of the logarithmic spiral line, and a circle is drawn with O as the center and R1 as the radius to form an impeller profile line; The distance between the intersection point of each ray with the impeller profile and the intersection point of the ray with the first spiral line segment (124) is the opening degree of the ray, and along the extension direction of the first spiral line segment (124), the difference in the opening degree between two adjacent rays is a constant value; Taking the impeller profile as a reference and according to a preset opening difference, the intersection position of each ray and the first profile of the volute (12) is corrected, and the N corrected intersection points are sequentially fitted to form a new second spiral line segment (131); the first straight line segment (121), the second straight line segment (122), the volute tongue profile (123), the second spiral line segment (131) and the third straight line segment (125) are sequentially connected to form the second profile of the volute (13).

2. The method for drawing a volute profile according to claim 1, characterized in that: The first spiral line segment (124) includes a first segment (1241) and a second segment (1242), and the spiral tongue profile (123) is connected to the second segment (1242) via the first segment (1241); The second segment (1242) includes a first arc segment (12421) and a second arc segment (12422), the first arc segment (12421) has a starting point Z and an end point K, and the second arc segment (12422) has a starting point K and an end point U; The difference in the opening degrees corresponding to two adjacent rays on the first arc segment (12421) is preset to be y, and along the direction from the starting point to the end point of the first arc segment (12421), the intersection position of each ray corresponding to the first arc segment (12421) and the first profile line (12) of the volute is sequentially corrected according to the difference y with the starting point Z as a reference; The difference in the opening degrees corresponding to two adjacent rays of the second arc segment (12422) is preset to be x, and along the direction from the end point to the starting point of the second arc segment (12422), the intersection position of each ray corresponding to the second arc segment (12422) and the first profile line (12) of the volute is corrected in sequence according to the difference x and based on the starting point U; According to the above method, the corrected K point position of the first arc segment (12421) and the corrected K point position of the second arc segment (12422) meet the fitting conditions. At this time, all the corrected intersection points from point Z to point U are re-fitted with the first segment (1241) of the first spiral segment (124) to form a second spiral segment (131).

3. The method for drawing a volute profile according to claim 2, characterized in that: A point E is formed on the first arc segment (12421), and the angle between any two adjacent rays on the first arc segment (12421) is ∠ZOE; A point T is formed on the second arc segment (12422), the angle between any two adjacent rays on the second arc segment (12422) is ∠UOT=α1, the line segment ET is a horizontal line passing through the origin O, and the line segment OK is a vertical line.

4. The method for drawing a volute profile according to claim 3, characterized in that: The impeller radius R1 is selected according to the width W1 of the casing (31) and the height H1 of the casing (31), and the first volute profile (12) is formed according to the logarithmic spiral equation, including: A first spiral line segment (124) is generated according to the cylindrical coordinate equation of the logarithmic spiral R=R1*exp(ζ*t), wherein point T1 is the starting point of the logarithmic spiral, the logarithmic spiral passes through an angle of 360+α1, and point U is the end point of the logarithmic spiral; The angle between the third straight line segment (125) and the vertical line passing through the origin O is α3. Since the height H1 of the chassis (31), the position of the point U and the angle α3 are all preset values, the position of the end point A of the third straight line segment (125) can be determined; The length L0 of the first straight line segment (121) is the width of the volute air outlet, which is a preset value, and the first straight line segment (121) is a horizontal straight line, so the position of the end point B of the first straight line segment (121) can be obtained; The angle between the second straight line segment (122) and the vertical line passing through the origin O is α2, the distance between the center of the volute tongue profile (123) and the vertical line passing through the origin O is W2, W2 and α2 are preset values, and the volute tongue profile (123) is tangent to the second straight line segment (122) and the first spiral line segment (124) respectively, so that the starting point C and the end point D of the volute profile can be obtained; The first straight line segment (121), the second straight line segment (122), the volute tongue profile (123), the first spiral line segment (124) and the third straight line segment (125) connected in sequence constitute the first profile (12) of the volute.

5. The method for drawing a volute profile according to claim 4, characterized in that: 45°＞α2＞α3＞0°，α1≤15°。 6. The method for drawing a volute profile according to claim 4, characterized in that: The length of line segment ET is less than or equal to W1.

7. A method for drawing a check valve profile, characterized in that: include: The check valve profile (2) is generated based on the second profile (13) of the volute obtained by the method for drawing the profile of the volute according to any one of claims 1 to 6.

8. The method for drawing a check valve profile according to claim 7, characterized in that: Generating a check valve profile (2) based on the second profile (13) of the volute comprises: Rotate α4 degrees with the starting point of the first straight line segment (121) as the center; The check valve profile (2) comprises a fourth straight line segment (21), a first arc segment (22), a fifth straight line segment and a second arc segment (23) which are connected in sequence, and the fifth straight line segment and the first straight line segment (121) overlap; The starting point of the fourth straight line segment (21) is V and the end point is W, and the length of the fourth straight line segment (21) is determined according to the diameter of the exhaust pipe; The height of the check valve is H2, and the diameter of the first arc segment (22) is R a , the diameter of the second arc segment (23) is R b The check valve profile (2) is generated according to the length of the fourth straight line segment (21), the diameter of the first arc segment (22), the diameter of the second arc segment (23) and the position of point A.

9. The method for drawing a check valve profile according to claim 8, characterized in that: Generating the check valve profile (2) according to the length of the fourth straight line segment (21), the diameter of the first arc segment (22), the diameter of the second arc segment (23) and the position of point A comprises: Draw a horizontal line L0, the distance between point A and L0 is equal to H2; With point A as the center and R b Draw a circle with radius L0 and locate O1 at the intersection point. Take O1 as the center and R as the center. b The intersection point of a circle with a radius L0 and L0 is the starting point V of the fourth straight line segment (21), and a second curve is determined; Determine the length VW according to the diameter of the discharge pipe, and then determine the position of the end point W of the fourth straight line segment (21), thereby determining the fourth straight line segment (21); With point B as the center and R a Draw a circle with radius L0 and locate O2 at the intersection point. Take O2 as the center and R as the center. a A second arc segment (23) is obtained by drawing a circle with the radius, and the fourth straight line segment (21), the first arc segment (22), the fifth straight line segment, and the second arc segment (23) connected in sequence form a check valve profile (2).

10. An air duct structure, characterized in that: The invention comprises a check valve and a volute (1), wherein the volute (1) is made according to the second volute profile (13) described in any one of claims 7 to 9, and the check valve is made according to the check valve profile (2) described in any one of claims 7 to 9.

11. A range hood, characterized in that: Including the air duct structure described in claim 10.

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