Double-air-inlet centrifugal fan

Abstract

The invention provides a double-air-inlet centrifugal fan which comprises a volute, double-air-inlet impellers and a motor. The double-air-inlet impellers are arranged on a rotating shaft of the motor and are arranged in the volute. The volute comprises a front cover plate, a rear cover plate and a volute coaming arranged between the front cover plate and the rear cover plate. The positions, aligned with the double-air-inlet impellers, of the front cover plate and the rear cover plate are provided with a front air-inlet channel and a rear air-inlet channel respectively. The volute coaming is provided with an air outlet channel. The position, corresponding to the air outlet channel, of the volute is provided with a volute tongue. The volute tongue comprises a volute tongue curved face, and the volute tongue curved face is located on one side of the air outlet channel and is an inwards-concave and asymmetric curved face. According to the double-air-inlet centrifugal fan, the inwards-concave and asymmetric curved face is adopted for the volute tongue curved face, on one hand, rotating noise can be reduced, on the other hand, a deep tongue form is adopted for the volute tongue contour line close to an impeller front end ring and an impeller rear end ring, a shallow tongue form is adopted for the volute tongue contour line close to an impeller middle disc, so that the problem caused by uneven outlet speed distribution of the impellers can be avoided, and thus air volume and air pressure are increased, and efficiency are improved easily.

Description

technical field [0001] The invention relates to a fan, in particular to a double-inlet centrifugal fan, which belongs to the improvement technology of the double-inlet centrifugal fan. Background technique [0002] At present, high-suction range hoods have become the mainstream of the industry. The double-inlet centrifugal fan has the characteristics of large flow coefficient, high pressure coefficient and compact structure, which meets the needs of high-suction range hoods. [0003] There is a tongue-shaped structure near the volute outlet of the centrifugal fan, called the volute tongue, which is used to divert the airflow directed to the volute outlet and prevent part of the gas from circulating in the volute. According to the length of the snail tongue and the radial distance from the snail tongue to the impeller, the snail tongue is divided into sharp tongue, deep tongue, shallow tongue and flat tongue. The sharp tongue is the longest and the radial distance from the i...

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Problems solved by technology

[0007] In the above scheme, since the curved surface of the volute tongue is a concave curved surface, the frequency of the rotational noise generated by the impact and disturbance of the impeller outlet air on the volute tongue has a certain phase difference along the axial direction, which is beneficial to reduce the rotational noise. On the other hand, due to The contour line of the volute tongue close to the front and rear end rings of the impeller adopts the form of deep tongue, and the contour line of the volute tongue close to the middle plate of the impeller adopts the form of shallow tongue, which overcomes the problem caused by the uneven distribution of the impeller outlet speed, and is conducive to improving the air volume and air volume. pressure and efficiency

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