A centrifugal fan with labyrinth-type overlap

Abstract

The present invention relates to the field of fan technology, and in particular to a centrifugal fan with a labyrinth-type overlap, comprising at least two upper annular baffles connected to the inner wall of the impeller front cover plate and at least two lower annular baffles connected to the outer wall of the air inlet, which cooperate with each other to form a labyrinth-type overlap. The inner diameter of two adjacent upper annular baffles gradually decreases from front to back, and the outer diameter of two adjacent lower annular baffles gradually increases from front to back. The overlap gap of the present invention is a labyrinth-type overlap, which makes it easy to install, improves assembly and processing efficiency, increases processing errors, makes it easy to process, and reduces processing costs.

Description

Technical Field

[0001] The invention relates to the technical field of fans, and in particular to a centrifugal fan with a labyrinth-type overlap. Background Art

[0002] There are many gaps in the fan, and the pressures at both ends of the gaps are different. Gas leaks from the high-pressure side to the low-pressure side through the gaps. As a result, the gas that obtains a certain amount of energy from the fan is not completely transported out, but loses the energy in the form of loss. The leakage location in the fan varies depending on the structure, and generally occurs at the overlap between the air inlet and the impeller. The smaller the overlap gap, the less leakage; the longer the overlap length, the less leakage, the higher the fan efficiency, and the lower the noise.

[0003] During the production process, the overlap gap of the fan after assembly is greatly affected by the manufacturing method. The overlap parts are machined and precisely positioned, with small overlap gap, less leakage, and high fan efficiency, but the processing cost is high and the processing time is long, so it is not often used. The overlap parts are processed by pressing, spinning, welding, etc., with large dimensional tolerances, large overlap gaps, large leakage, and reduced fan efficiency, but the processing cost is low and the production efficiency is high, so it is widely used. Summary of the invention

[0004] The purpose of the present invention is to provide a labyrinth-type overlapped centrifugal fan with less leakage, high efficiency, convenient processing and manufacturing, low processing cost, convenient installation and maintenance, and easy to implement and popularize in view of the shortcomings of the prior art.

[0005] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0006] A centrifugal fan with a labyrinth-type overlap includes an air inlet, a casing, an impeller and a motor, and also includes at least two upper annular baffles connected to the inner wall of the impeller front cover plate and at least two lower annular baffles connected to the outer wall of the air inlet, which cooperate with each other to form a labyrinth-type overlap.

[0007] Furthermore, the inner diameters of two adjacent upper annular baffles gradually decrease from front to back, and the outer diameters of two adjacent lower annular baffles gradually increase from front to back, and Da>Daa>Dc; Da is the inner diameter of the first upper annular baffle, Dc is the inner diameter of the penultimate upper annular baffle, and Daa is the outer diameter of the penultimate lower annular baffle.

[0008] Further, Db>Daa>Dc, or Da>Daa>Db; Db is the inner diameter of any upper annular baffle in the middle.

[0009] Furthermore, the axial distance between the two adjacent upper annular baffles is equal, and the axial distance between the two adjacent lower annular baffles is equal.

[0010] Furthermore, the inner diameter of the upper annular baffle decreases from front to back, and the outer diameter of the lower annular baffle increases from front to back accordingly.

[0011] Furthermore, the tolerance of the overlap depth C is 0-15 mm, the overlap gap A is 0-5 mm, and the radial fit gap B between the air inlet and the impeller is 3-5 mm.

[0012] Furthermore, the first upper annular baffle is 3 to 5 mm away from the impeller inlet end face, and the first lower annular baffle is 3 to 5 mm away from the air inlet outlet end face.

[0013] Furthermore, the number of the upper annular baffles and the number of the lower annular baffles are equal, both of which are 2 to 5.

[0014] Beneficial effects: The lap gap of the present invention is a labyrinth-like lap, and the airflow therein repeatedly changes in rapid contraction and rapid expansion, which greatly increases the leakage resistance and reduces the leakage amount. It can effectively reduce the gas bypassing the impeller front cover plate and leaking from the lap gap, thereby improving the efficiency of the fan; the lap depth is flexible and has a large adjustable range, which increases the assembly error and reduces the impact of the lap depth on the performance of the fan, making it easy to install and improving the assembly and processing efficiency; the error tolerance of the fitting gap is increased, the processing error is increased, easy processing is achieved, and the processing cost is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A partial enlarged diagram of the overlap gap Figure 1 ;

[0016] Figure 2 A partial enlarged diagram of the overlap gap Figure 2 ;

[0017] Figure 3 A partial enlarged diagram of the overlap gap Figure 3 ;

[0018] Figure 4 A partial enlarged diagram of the overlap gap Figure 4 ;

[0019] Figure 5 It is a schematic diagram of the overall structure of the present invention;

[0020] In the figure, there are air inlet 1, impeller 2, casing 3, motor 4, and impeller front cover 5. DETAILED DESCRIPTION

[0021] The present invention will be further described below in conjunction with specific embodiments and accompanying drawings.

[0022] In the present invention, the upper annular baffle from front to back refers to from a to c, and the lower annular baffle from front to back refers to from cc to aa.

[0023] Embodiment 1

[0024] Figure 5 A centrifugal fan with a labyrinth-type overlap is presented, comprising an air inlet 1, an impeller 2, a casing 3 and a motor 4, and also comprising at least two upper annular baffles connected to the inner wall of the impeller front cover 5 and at least two lower annular baffles connected to the outer wall of the air inlet 1, which cooperate with each other to form a labyrinth-type overlap.

[0025] The inner diameters of two adjacent upper annular baffles gradually decrease from front to back, and the outer diameters of two adjacent lower annular baffles gradually increase from front to back, and Da>Daa>Dc; Da is the inner diameter of the first upper annular baffle, Dc is the inner diameter of the penultimate upper annular baffle, and Daa is the outer diameter of the penultimate lower annular baffle.

[0026] The radial matching clearance B between the air inlet 1 and the impeller 2 is preferably 3 to 5 mm. The first upper annular baffle is 3 to 5 mm away from the inlet end face of the impeller 2, and the first lower baffle is 3 to 5 mm away from the outlet end face of the air inlet 1. The above distances can also be fine-tuned according to actual conditions.

[0027] The number of the upper annular baffles and the number of the lower annular baffles are equal, both of which are 2 to 5.

[0028] like Figure 1 As shown, the number of upper annular baffles and lower annular baffles in this embodiment is 3, that is, the upper annular baffles are a, b and c from front to back, Da>Db>Dc, and the lower annular baffles are cc, bb and aa from front to back, Daa>Dbb>Dcc.

[0029] Each lower annular baffle may be aligned with each upper annular baffle, or may be staggered with the corresponding upper annular baffle.

[0030] The upper annular baffle and the lower annular baffle at the overlapped part of the fan air inlet 1 and the impeller 2 in this embodiment are distributed in a step-like manner, and are opposed to each other up and down to form a labyrinth-shaped leak-proof cavity. In the prior art, high-pressure gas bypasses the impeller front cover 5 and leaks from the overlapped gap, affecting the performance of the fan. In the present invention, when the above-mentioned high-pressure gas passes through the overlapped gap of the structure, the change of "rapid contraction-rapid expansion-rapid contraction-rapid expansion-rapid contraction-rapid expansion" occurs, which greatly increases the leakage resistance, effectively reduces the leakage amount, and improves the fan pressure and efficiency.

[0031] After the traditional fan is manufactured, the overlap gap between the air inlet 1 and the impeller 2 is a fixed value. The overlap structure of the present invention forms a tapered overlap gap A, and a variable overlap gap is achieved by adjusting the overlap depth C. The tolerance of the overlap depth C is 0-15mm, and the overlap gap A is preferably in the range of 0-5mm, which is adjusted according to the actual size of the fan.

[0032] It can achieve a smaller overlap gap A and a larger fit gap B, B>A. For conventional fans, B=A. The larger the fit gap, the easier it is to process.

[0033] Embodiment 2

[0034] The parts not mentioned in this embodiment are as described in the above embodiments.

[0035] The axial distance between the two adjacent upper annular baffles is equal, and the axial distance between the two adjacent lower annular baffles is equal; that is, L a-b = L b-c = L aa-bb = L bb-cc .

[0036] The inner diameter of the upper annular baffle decreases from front to back, and the outer diameter of the lower annular baffle increases from front to back; that is, Da-Db= Db-Dc= Daa-Dbb= Dbb-Dcc, which changes linearly.

[0037] like Figure 2 As shown, Da>Daa>Db; Db is the inner diameter of the upper annular baffle in the middle.

[0038] Embodiment 3

[0039] The parts not mentioned in this embodiment are as described in the above embodiments.

[0040] like Figure 3 As shown, in this embodiment, the number of upper annular baffles and lower annular baffles are both 5, and the middle upper annular baffles include b1, b2, and b3, that is, the upper annular baffles are a, b1, b2, b3, and c from front to back, the middle upper annular baffles include bb1, bb2, bb3, and the lower annular baffles are cc, bb1, bb2, bb3, and aa from front to back.

[0041] In this embodiment, Da>Db1>Db2>Db3≥Daa>Dc.

[0042] Embodiment 4

[0043] The parts not mentioned in this embodiment are as described in the above embodiments.

[0044] like Figure 4 As shown, in this embodiment, the number of the upper annular baffles and the number of the lower annular baffles are both two. Combining the above embodiments, it can be clearly seen that the upper annular baffles and the lower annular baffles do not need to change linearly as long as they do not affect assembly.

[0045] In summary, the overlap gap of the present invention is a labyrinth overlap, and the airflow therein repeatedly changes in rapid contraction and rapid expansion, which greatly increases the leakage resistance and reduces the leakage amount, and can effectively reduce the gas bypassing the impeller front cover 5 and leaking from the overlap gap, thereby improving the efficiency of the fan; the overlap depth is flexible and has a large adjustable range, which increases the assembly error and reduces the impact of the overlap depth on the performance of the fan, making it easy to install and improving the assembly and processing efficiency; the error tolerance of the matching gap is increased, the processing error is increased, easy processing is achieved, and the processing cost is reduced.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A labyrinth-type overlapping centrifugal fan, comprising an air inlet, a casing, an impeller and a motor, characterized in that: It also includes at least two upper annular baffles connected to the inner wall of the impeller front cover plate and at least two lower annular baffles connected to the outer wall of the air inlet, which cooperate with each other to form a labyrinth overlap; the inner diameters of two adjacent upper annular baffles gradually decrease from front to back, and the outer diameters of two adjacent lower annular baffles gradually increase from front to back, and Da>Daa>Dc; Da is the inner diameter of the first upper annular baffle, Dc is the inner diameter of the last upper annular baffle, and Daa is the outer diameter of the last lower annular baffle; the tolerance of the overlap depth C is 0~15mm, and the overlap gap A is 0~5mm; the radial matching gap B between the air inlet and the impeller is 3~5mm.

2. The centrifugal fan with labyrinth-type overlap according to claim 1, characterized in that: Db>Daa>Dc, or Da>Daa>Db; Db is the inner diameter of any upper annular baffle in the middle.

3. The centrifugal fan with labyrinth-type overlap according to claim 1, characterized in that: The axial distance between the two adjacent upper annular baffles is equal, and the axial distance between the two adjacent lower annular baffles is equal.

4. The centrifugal fan with labyrinth-type overlap according to claim 1, characterized in that: The inner diameter of the annular baffle decreases from front to back, and the outer diameter of the lower annular baffle increases from front to back.

5. The centrifugal fan with labyrinth-type overlap according to claim 1, characterized in that: The first upper annular baffle is 3 to 5 mm away from the impeller inlet end face, and the first lower annular baffle is 3 to 5 mm away from the air inlet outlet end face.

6. The centrifugal fan with labyrinth-type overlap according to claim 1, characterized in that: The number of the upper annular baffles and the number of the lower annular baffles are equal, both of which are 2 to 5.

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