Application
Y4-70 II boiler induced draft fan designed for small (0.5~4 t/ h) industrial boilers burning various coal qualities or equipped with smoke and dust removal devices. It is applicable to any boiler with equivalent performance under the conditions of gas temperature t=240 ℃ , atmospheric pressure Pa=101300Pa, gas density ρ=0.685kg/m³. However, the maximum temperature shall not exceed 250C.
Type
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1. The induced draft machine is made of single suction, and the machine numbers are No. 4, 5, and 6.
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2. Induced draft fans can be made into two types: left-handed and right-handed. Looking at the fan from the transmission part, if the impeller rotates clockwise, it is called right-handed, represented by "right"; if it rotates counterclockwise, it is called left-handed, represented by "left".
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3. The air outlet position of the fan is indicated by the air outlet angle of the casing. Both left-hand and right-hand fan can be made into three angles: 0°, 90°, and 180°.
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4. The fan's transmission mode is C type, using V-belt drive.
Structural characteristics
Y4-70 II boiler induced draft fan adopts V-belt (C-type) drive. In order to obtain the required air volume and air pressure by changing the diameter of the motor pulley according to the actual situation. The air inlet of the fan adopts convergent streamline shape. The geometric dimensions are the same as those of the 4-72 series, which not only makes the air inlet processing technology and work clamp mold universal, but also has better aerodynamic performance of the fan. The maximum efficiency can reach 83%. The impeller adopts Q345 (16Mn) flat blades, which are easy to manufacture, not easy to accumulate dust, and have good strength and wear resistance. The casing is equipped with a dust cleaning door to facilitate the removal of dust accumulated on the blades to ensure the dynamic balance of the impeller. The fan consists of an impeller, a casing, an air inlet, a transmission part, a bracket, a motor slide rail and other parts.
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1. The impeller has 12 backward-inclined flat blades made of Q345 (16Mn), welded between the arc-mouth conical front disc and the flat rear disc. After static and dynamic balance correction, it runs smoothly, has high strength and wear resistance, and has a long service life.
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2. The casing is welded with steel plates into a volute casing. A dust cleaning door is opened on the volute to facilitate the removal of dust accumulated on the blades and ensure the balance and aerodynamic performance of the impeller.
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3. The convergent-divergent air inlet is made into an integral structure and fixed to the inlet side of the casing with bolts.
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4. The transmission part, the main shaft is made of high-quality steel and supported by ball bearings. Two parallel bearing seats are self-cooled by bearing grease and fan blades, and the structure is simple.
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5. The bracket is welded with steel sections and plates to support the transmission group, and the bottom surface is in contact with the foundation.
Performance and selection
The design and use units shall determine the selected induced draft fan model in the selection curve according to the selected flow rate and total pressure. The specific performance and matching motor shall be selected from the performance and optional parts table.
The performance of each speed in the performance and options table is the performance within the range of 90% of the maximum efficiency divided into 8 performance points according to the flow rate. The performance table shall prevail when ordering.
The factory inspection performance of the fan is that the deviation of the total pressure value at the required flow rate does not exceed +5% of the designed total pressure value.
Select the curve diagram and the performance and optional parts table, and calculate according to the flue gas medium when the gas temperature t = 240 ℃ , atmospheric pressure Pa = 101300Pa, and gas density ρ = 0.685kg/m³.
If the fan operating conditions do not match the conditions in the performance diagrams and tables, the performance should be converted according to the relevant formulas.
