Abstract: A ventilating fan includes a sirocco fan disposed in a box-shaped body and an adapter connected to an air outlet of the sirocco fan. The sirocco fan is composed of two opposite scroll plates with scroll shapes and a casing plate sandwiched between the two scroll plates. An overall air inlet of the sirocco fan is disposed on the first scroll plate and a central line of the air outlet of the adapter is offset towards the second scroll plate. The present invention is advantageous in that no turbulence is generated at the adapter and the wind amount of the ventilating fan is thus ensured and noise is reduced. Therefore, the present invention can provide a small air blowing device with high efficiency and improve stability of performance of the product.

Abstract: Disclosed is a structure for reducing noise of a ventilating fan. The structure includes an orifice plate fixed on a scroll casing and is shaped to be an annular and semi-surrounding hollow structure in order to match with the shape of an air inlet of the scroll casing, and to cover only the air inlet of the scroll casing. The noise generated by an air blower of the ventilating fan can be directed along a bell mouth of the scroll casing of the ventilating fan after being emitted from the air inlet of the scroll casing, and then can be smoothly sucked by the orifice plate. The sucked-in noise can repeatedly collide with the orifice plate and be diffused, thereby the energy being gradually weakened and the sound pressure thereof being decreased.

Abstract: A ventilation device comprises: a body, a fan disposed In the body, and an adapter connected with an air outlet of the body. Two or more pipe coupling parts are disposed in sequence from a side of an air Inlet of the adapter to a side of an air outlet of the adapter, and each pipe coupling part is provided with a protruding circular ring with a diameter larger than that of the respective pipe coupling part at a root thereof. An air guide structure Is disposed in the adapter, a pipe is fitted over the pipe coupling part and Is abutted against the protruding circular ring located at the root to be fixed, and the air guide structure Is engaged to an inside of the protruding circular ring of the adapter.

Abstract: A ventilating fan includes a sirocco fan disposed in a box-shaped body and an adapter connected to an air outlet of the sirocco fan. The sirocco fan is composed of two opposite scroll plates with scroll shapes and a casing plate sandwiched between the two scroll plates. An overall air inlet of the sirocco fan is disposed on the first scroll plate and a central line of the air outlet of the adapter is offset towards the second scroll plate. The present invention is advantageous in that no turbulence is generated at the adapter and the wind amount of the ventilating fan is thus ensured and noise is reduced. Therefore, the present invention can provide a small air blowing device with high efficiency and improve stability of performance of the product.

Abstract: A ventilation device comprises: a body, a fan disposed in the body, and an adapter connected with an air outlet of the body. Two or more pipe coupling parts are disposed in sequence from a side of an air inlet of the adapter to a side of an air outlet of the adapter, and each pipe coupling part is provided with a protruding circular ring with a diameter larger than that of the respective pipe coupling part at a root thereof. An air guide structure is disposed in the adapter, a pipe is fitted over the pipe coupling part and is abutted against the protruding circular ring located at the root to be fixed, and the air guide structure is engaged to an inside of the protruding circular ring of the adapter. The ventilation device according to the present invention has the following advantages. Pipes with different outer diameters can be conveniently installed to the ventilation device. In addition, excellent seal and reduction of air resistance and noise can be achieved.