Selection and application of fan performance (I) Description of fan performance: 1. № 10, 12, 16, 20 are converted according to dimensionless performance of № 10 model. 2. № 5, 6, 8 are converted according to dimensionless performance of № 5 model. 3. № 5 and below shall be determined according to the performance of the measured prototype. Note: According to the dimensionless performance curve conversion formula, total pressure H=ρ u2 H (Pa) flow Q=900 π D22 uQ (m3/h) shaft power N=N × D22u3 ρ/4000 (kw), where D2 - impeller outer diameter (m) u - impeller outer edge linear speed (m/s) ρ - gas density (Kg/m3), the required power rate shall be based on shaft power plus mechanical loss and motor reserve. 4. The solid line is № 5 model, and the dotted line is № 10 model. The performance of the fan is expressed by the flow, total pressure, main shaft speed, shaft power, efficiency and other parameters of the fan, and there are certain relationships between the parameters, which are listed in the following table. The relationship of fan performance parameters changes density ρ, speed n changes speed n, atmospheric pressure P, gas temperature t Q1/Q2=n1/n2 H1/H2=(n1/n2) 2 ρ 1/ρ 2 N1/N2=(n1/n2) 3 ρ 1/ρ 2 η 1=η 2 Q1/Q2=n1/n2 H1/H2=(n1/n2) 2 (P1/P2) (273+t2/273+t1) N1/N2=(n1/n2) 3 (P1/P2) (273+t2/273+t1) η 1=η 2 Note: 1. In the middle, Q represents flow (m3/h), H represents total pressure (Pa), N represents shaft power (kw), η represents full pressure efficiency, ρ represents density (kg/m3), t represents temperature (℃), n represents speed (r/min), and P represents atmospheric pressure (Pa). 2. The footnote symbol 2 indicates the known performance and related parameters, and the footnote symbol 1 indicates the required performance and related parameters. （

Yunnan Wet electrostatic precipitator Classified by layers. There are many classification methods for fans, which can be roughly classified according to the following levels: (1) According to the level of pressure generated, they can be divided into: volumetric: reciprocating and rotary; Turbine type: centrifugal, axial flow, mixed flow and cross flow, jet type. Fan generally refers to turbine type, namely centrifugal, axial, mixed flow, cross flow and other forms. Its main characteristics are: centrifugal fan: higher pressure, but smaller air volume. Axial flow fan: higher air volume, but lower pressure. Mixed flow fan: the air volume and pressure are between centrifugal fan and axial fan. Horizontal fan: with high dynamic pressure, it can obtain flat airflow. (2) major Wet electrostatic precipitator According to the different materials used, it can be divided into:; Iron shell fan (ordinary fan), glass fiber reinforced plastic fan, plastic fan, aluminum fan, stainless steel fan, etc. (3) According to the direction of gas flow, it can be divided into centrifugal type, axial flow type, diagonal flow type (mixed flow type) and cross flow type. (4) According to the flow direction of the airflow entering the impeller, it can be divided into axial flow fan, centrifugal fan and diagonal flow (mixed flow) fan. (5) Wet electrostatic precipitator Price It can be divided into: press in local fans and flame-proof motors placed outside or inside the flow channel, and flame-proof motors placed inside the explosion-proof sealing chamber of the extraction type local fans. (6) According to the form of pressurization, it can also be divided into single-stage, two-stage or multi-stage pressurization fans

2. The influence of the total pressure deviation Δ H of the fan itself was not considered during selection. When the actual total pressure of the fan was positive deviation, the flow increased; When the actual total pressure of the fan is negative deviation, the flow decreases. See (a) below. The relationship between the deviation of the pipe network characteristic curve and the total pressure and the flow can be eliminated by one of the following methods when the fan starts to officially operate after new installation, or when the flow is too large or too small during use. 1. Use the opening and closing of throttling device to adjust the flow. 2. Increase or decrease the flow by increasing or decreasing the fan speed. 3. Use a new fan with higher or lower pressure to increase or decrease the flow. 4. Change the pipe network to reduce the resistance coefficient of the pipe network to increase the flow. It must be pointed out that throttling devices are generally used to regulate the flow. However, when the actual flow is much larger than the required flow, this method wastes too much power and is very uneconomical. If conditions permit, the fan speed is usually reduced or the fan with lower pressure is replaced. When the throttling device is fully open, the flow is still too small. At this time, the throttling device has lost its function, so try to reduce the resistance coefficient of the pipe network to increase the flow, or increase the fan speed and replace the fan with higher pressure. However, the speed of the fans directly connected to the motor and the coupling cannot be changed generally. Only the fan driven by the pulley can increase or decrease the speed by changing the diameter of the pulley, but the speed of the fan cannot exceed the speed max in the performance and selection table.

major Wet electrostatic precipitator The wet electrostatic precipitator mainly has two structural forms. One is to use corrosion-resistant conductive materials (which can be non-metallic materials with excellent conductivity or metal materials with corrosion-resistant characteristics) as the dust collector, and the other is to use non-conductive non-metallic materials as the dust collector by forming a conductive water film through water spray or overflow. Wet electrostatic precipitators can also be divided into cross flow type (horizontal) and vertical flow type (vertical) according to the flow direction of waste gas. The cross flow type is mostly plate structure, Yunnan Wet electrostatic precipitator The gas flows in and out in the horizontal direction, and the structure is similar to the dry electrostatic precipitator; The vertical flow type is mostly tubular structure, and the gas flow direction is vertical. Generally speaking, the efficiency of vertical flow wet electrostatic precipitator is twice as high as that of cross flow wet electrostatic precipitator under the condition of the same ventilation cross-sectional area. The dust deposited on the electrode plate can be washed down by water. Wet dust removal can avoid the re flying of captured dust and achieve high dust removal efficiency. Since there is no rapping device, the operation is also more reliable. The device that forms conductive film on the surface of the dust collector by means of water spray or overflow water has problems of corrosion, sludge and sewage treatment. It is only used when the dust concentration of the gas is low and the dust removal efficiency is required to be high; The wet electrostatic precipitator using corrosion-resistant conductive materials as dust collector does not need long-term water spraying or overflow water, Wet electrostatic precipitator Price Regular flushing is only carried out according to the operating conditions of the system, and only a small amount of water is consumed. This part of water can be recycled, and the dust collection system is basically free of secondary pollution.

Fans can be classified into several types according to the materials used, such as iron shell fans (ordinary fans), glass fiber reinforced plastic fans, plastic fans, aluminum fans, stainless steel fans, etc. Wet electrostatic precipitator Price In the direction of gas flow. Fans can be classified into centrifugal, axial, diagonal (mixed flow) and cross flow fans according to the direction of gas flow. (1) Centrifugal fan. The airflow enters the impeller of the fan axially and flows mainly along the radial direction. This type of fan is made according to the principle of centrifugal action, and its products include centrifugal fan, centrifugal blower and centrifugal compressor. (2) Axial flow fan. The airflow enters the impeller of the fan axially and flows approximately along the axis on the cylindrical surface. Such fans include axial fans, axial blowers and axial compressors. (3) Rotary fan. Yunnan major Wet electrostatic precipitator Use the rotor rotation to change the air chamber volume to work. Common varieties include Roots blower and rotary compressor.