There are many types of fans, generally: centrifugal, axial, and Roots fans. Generally, the induced and blower fans of boilers are centrifugal fans. The structure of the boiler's induced and blower fans are the same, but their functions and installation positions are different.
When the impeller of a centrifugal fan is driven by the motor to rotate, the gas filled between the blades rotates with the impeller. Under the action of centrifugal force,
The gas is thrown out from the channel between the blades, and the gas is sent out from the outlet of the impeller. When the outflow of gas creates a vacuum in the impeller space, the outside gas will automatically enter the impeller to supplement. Due to the continuous operation of the fan, the gas is sucked in and pressed out to form a continuous flow of gas, thus forming a continuous work.
From the perspective of the fan, the blower and induced draft fan are all produced by the rotation of the fan blades driven by the motor. Although it is more complicated than the electric fan, there is no difference in essence. The different functions of the induced draft fan are determined by the location where they are installed. The former is located at the back end of the boiler and blows air to the flue outside the boiler, generating negative pressure on the furnace and guiding the flue gas, so it is called an induced draft fan; On the contrary, it is located at the front end of the boiler and blows air into the boiler, so it is called a blower.
The noise of the blower and induced draft fan in the boiler room is generally around 90 decibels. Because the boiler flue gas temperature is as high as 180 ℃, the use of enclosed sound insulation will cause poor heat dissipation, excessive motor temperature, and even burn the motor. Therefore, in the process, the fan noise reduction and energy saving are combined.
Through practice, the comprehensive treatment plan for energy saving and noise reduction of boiler fans is: keep the process layout of the boiler room unchanged, place the blower and induced draft fan in the sound insulation room separately, connect them to the main engine with a ventilation pipe, and place it on the top of the sound insulation room. An air inlet is provided on the upper or the wall, and a muffler is installed for air intake in the computer room. In the plane layout, the blower is close to the side of the boiler room, the air inlet is on the upwind side, and the motor is placed in the middle of the air flow channel.
When the boiler is running, due to the negative pressure generated by the blower in the sound insulation room, a large amount of outdoor fresh air will automatically enter the sound insulation room. First, it exchanges heat with the induced draft fan motor to cool it down, and the indoor temperature is maintained at about 50°C.
