Volute of centrifugal fan

Abstract

The invention discloses a volute of a centrifugal fan. The volute comprises a front cover, a back cover and an annular wall connected between the front cover and the back cover; a volute molded line of the volute comprises a starting line AC located at one end of the molded line and an ending line MN located at the other end of the molded line; the starting line AC and the ending line MN are adjacent to a fan air outlet; the volute is characterized in that the volute molded line further comprises a first spiral line CD with the unchanged divergence angle and a second spiral line EM with the tapered divergence angle; the first spiral line CD is connected with the starting line AC; the second spiral line EM is connected with the ending line MN; and the front-and-back width, on the outer sideedge of the fan air outlet, of the annular wall is larger than that on the inner side edge. The volute has the advantages as follows: according to the volute of the centrifugal fan, through section transformation, the left-and-right size of the volute is converted into the front-and-back size change, so that the smooth degree of collection and passing of the air flow inside the volute is increased, the maximum static pressure and the static pressure of the effective air volume section are relatively greatly increased, the large-volute effect is realized under the condition of small size, andthe user experience is improved.

Description

technical field [0001] The invention relates to a fan, in particular to a centrifugal fan volute. Background technique [0002] Centrifugal fans have been widely used in range hoods for their advantages of high suction, low noise, and compact structure. The volute is one of the core components of the centrifugal fan. Its function is to concentrate the gas leaving the impeller, export it to the outlet of the volute, and convert the dynamic pressure into static pressure. The volute structure of the existing centrifugal fan includes a volute top plate, a volute bottom plate, and a volute coaming plate connecting the volute top plate and the volute bottom plate, wherein the volute top plate and the volute bottom plate have the same profile except for the volute tongue. The traditional volute design is generally carried out according to the unary theory, and there are two assumptions, that is, assuming that the flow parameters on the inlet circumference are uniformly distributed...

AI Technical Summary

Problems solved by technology

But in fact, due to the non-axisymmetric shape of the volute, especially the influence of the volute tongue, a non-uniform pressure field will be formed at the outlet of the impeller, which will inevitably make the flow field at the outlet of the impeller, that is, the flow field at the inlet of the volute.

Since the one-element theory does not consider the non-uniformity of the inlet circumferential flow parameters and the influence of the flow field in the circumferential plane of the volute, the performance of the volute designed according to this theory is not good, especially in the high back pressure working state.

[0003] The volute structures of various centrifugal fans are also disclosed in the prior art, such as "A Centrifugal Fan for Range Hood and Its Volute" as disclosed in the Chinese invention patent No. ZL 201110118687.5 (authorized announcement No. CN 102182707 B). Shell profile line generation method", the volute includes a volute top plate, a volute bottom plate and a volute coaming, the contour line of the inner side of the volute coaming is the volute profile, and the volute profile is formed by the first straight line DE , the first arc line EF, the second arc line FG, the helix line GH, and the second straight line segment HI are smoothly transitioned and connected. Although the volute adopts the above-mentioned volute profile, it is beneficial to improve the air volume and air volume of the centrifugal fan. pressure, efficiency and reduce aerodynamic noise, but the volute structure still does not fully consider the non-uniformity of the inlet circumferential flow parameters in the circumferential plane of the volute and the influence of the flow field, and the left and right dimensions of the volute are relatively large, which affects the product shape Generally, the left and right dimensions of the volute need to be partially modified or cut to meet the installation requirements, but this will easily lead to increased flow loss

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