Centrifugal fan

Abstract

A centrifugal fan comprises a machine shell, an impeller arranged in the machine shell, an air inlet pipe arranged on the machine shell and a front cover plate inserted in the impeller, and the center of a rear cover of the impeller is fixedly connected to a main shaft of a motor, and is characterized in that a plurality of radial ribs are arranged on the right side face of the rear cover plate, and a bearing seat is arranged in the air inlet pipe; a plurality of rib plates are symmetrically connected between the bearing seat and the air inlet pipe, a bearing is installed in the bearing seat, and the front end of the main shaft is connected in the bearing. The utility model has the beneficial effects that the ribs generate reverse centrifugal force when rotating to prevent gas in a high-pressure area from flowing towards the main shaft along the rear cover plate; the front end of the main shaft is connected in the bearing, so that the impeller can be prevented from shaking during rotation, a gap between a front cover plate of the impeller and a shell can be reduced, gas in a high-pressure area is prevented from converging to an inlet of the impeller, and non-contact sealing is realized; therefore, the problem that in the prior art, a sealing element needs to be replaced frequently due to abrasion is solved. Meanwhile, no friction force exists when the main shaft rotates, and mechanical loss of the fan can be reduced.

Description

Technical Field

[0001] This utility model relates to a centrifugal fan. Background Technology

[0002] The structure of a centrifugal fan includes a casing and an impeller. The impeller consists of a front cover plate, blades, and a rear cover plate. When the impeller rotates with the motor shaft, the gas between the blades also rotates with the impeller and gains centrifugal force, causing the gas to be thrown out from the outlet between the blades. The thrown-out gas is squeezed into the casing, increasing the gas pressure inside the casing and decreasing the pressure at the center of the impeller. Due to the gap between the rotating parts and the casing, part of the gas in the high-pressure zone flows back to the center of the impeller through the gap between the front cover plate and the casing, while the other part leaks out of the casing through the shaft seal along the gap between the rear cover plate and the casing, reducing the fan's efficiency. To address this, a sealing ring is usually installed between the front cover plate and the casing, and a shaft seal (sealing ring or sealing packing) is installed between the casing and the main shaft. The sealing ring and shaft seal will wear during operation and need to be replaced frequently. Utility Model Content

[0003] The purpose of this invention is to provide a centrifugal fan that, while ensuring fan efficiency, does not use sealing elements, thus overcoming the problem of frequent replacement due to wear of sealing elements.

[0004] The technical solution of this utility model is a centrifugal fan, which includes a casing, an impeller disposed in the casing, an air inlet pipe 1 on the casing inserted into the front cover plate 2 of the impeller, and a rear cover plate 6 of the impeller fixedly connected to the main shaft 8 of the motor at its center. The feature is that multiple radial ribs 5 are provided on the right side of the rear cover plate, a bearing seat 13 is provided in the air inlet pipe, multiple ribs 12 are symmetrically connected between the bearing seat and the air inlet pipe, a bearing 14 is installed in the bearing seat, and the front end of the main shaft is connected to the bearing.

[0005] The beneficial effects of this utility model are as follows: Ribs are provided on the rear cover plate. When the ribs rotate with the impeller, they generate centrifugal force, preventing gas in the high-pressure zone from flowing towards the main shaft along the gap between the rear cover plate 6 and the right side plate 7 of the casing. This eliminates the need for a shaft seal between the main shaft and the casing. The front end of the main shaft is supported by a bearing, which improves the stability of the impeller and greatly reduces the shaking during impeller rotation. This reduces the gap between the inner circle of the impeller front cover and the outer circle of the air inlet pipe, as well as the gap between the end face of the impeller front cover and the left side plate 3 of the casing. This significantly reduces the backflow of gas from the high-pressure zone to the center of the impeller, eliminating the need for a sealing ring between the front cover plate and the casing. Since there is no shaft seal or sealing ring on the fan, i.e., no contact seal, the problem of frequent replacement due to wear of sealing elements is eliminated. At the same time, there is no friction when the main shaft rotates, which reduces the mechanical wear of the fan. Attached Figure Description

[0006] Figure 1 This is a schematic diagram of the structure of this utility model.

[0007] Attached diagram symbols: 1-Air inlet pipe, 2-Front cover plate, 3-Left side panel of casing, 4-Blade, 5-Rib, 6-Rear cover plate, 7-Right side panel of casing, 8-Main shaft, 9-Motor, 10-Motor bracket, 11-Base, 12-Rib, 13-Bearing seat, 14-Bearing. Detailed Implementation

[0008] A centrifugal fan includes a casing, an impeller is provided in the casing, the impeller is composed of a front cover plate 2, blades 4 and a rear cover plate 6, an air inlet pipe 1 on the casing is inserted into the front cover plate 2 of the impeller, the center part of the rear cover plate 6 of the impeller is fixedly connected to the main shaft 8 of the motor, the motor is connected to the base 11 through the motor bracket 10, and the casing is also connected to the base 11.

[0009] Multiple radial ribs 5 are provided on the right side of the rear cover plate. A bearing seat 13 is provided in the air inlet pipe. Multiple rib plates 12 are symmetrically connected between the bearing seat and the air inlet pipe. A bearing 14 is installed in the bearing seat. The front end of the main shaft is connected to the bearing.

[0010] Ribs are installed on the rear cover plate. When the impeller rotates, the ribs generate centrifugal force to prevent gas in the high-pressure area from flowing towards the main shaft through the gap between the rear cover plate 6 and the right side plate 7 of the casing. This eliminates the need for a shaft seal between the main shaft and the casing. The front end of the main shaft is supported by a bearing, which improves the stability of the impeller and greatly reduces the shaking during impeller rotation. This reduces the gap between the inner circle of the impeller front cover and the outer circle of the air inlet pipe, as well as the gap between the end face of the impeller front cover and the left side plate 3 of the casing. This greatly reduces the backflow of gas from the high-pressure area to the center of the impeller, eliminating the need for a sealing ring between the front cover plate and the casing. Since there is no shaft seal or sealing ring on the fan, i.e., no contact seal, the problem of frequent replacement due to wear of sealing elements is eliminated. At the same time, there is no friction when the main shaft rotates, which reduces the power loss of the motor.

[0011] The rib has a length of 2 / 3 of the radius of the rear cover plate 6, and its outer end is flush with the outer circle of the rear cover plate. The gap between the rib and the right side plate of the housing is about 0.1 mm.

[0012] The gap between the end face of the front cover plate 2 and the left side plate of the casing is about 0.04 mm, and the gap between the inner circle of the front cover plate 2 and the outer circle of the air inlet pipe is about 0.02 mm.

[0013] The left end of the air inlet pipe 1 is trumpet-shaped.

Claims

1. A centrifugal fan, comprising a casing, an impeller disposed within the casing, an air inlet pipe (1) on the casing inserted into the front cover plate (2) of the impeller, and a rear cover plate (6) of the impeller fixedly connected at its center to the main shaft (8) of a motor, characterized in that, Multiple radial ribs (5) are provided on the right side of the rear cover plate. A bearing seat (13) is provided in the air inlet pipe. Multiple ribs (12) are symmetrically connected between the bearing seat and the air inlet pipe. A bearing (14) is installed in the bearing seat. The front end of the main shaft is connected to the bearing.

2. The centrifugal fan according to claim 1, characterized in that, The rib (5) has a length of 2 / 3 of the radius of the rear cover plate 6, the outer end of the rib is flush with the outer circle of the rear cover plate, and the gap between the rib and the right side plate of the housing is 0.1 mm.

3. The centrifugal fan according to claim 1, characterized in that, The gap between the end face of the front cover (2) and the left side plate of the casing is 0.04 mm, and the gap between the inner circle of the front cover (2) and the outer circle of the air inlet pipe is 0.02 mm.

4. The centrifugal fan according to claim 1, characterized in that, The left end of the air inlet pipe (1) is trumpet-shaped.

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