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.
Liupanshui major Wet dedusting equipment Fan performance parameters. The performance parameters of fan mainly include flow, pressure, power, efficiency and speed. In addition, the size of noise and vibration is also the main fan design index. Flow, also known as air volume, is expressed by the volume of gas flowing through the fan in unit time; Pressure, also known as wind pressure, refers to the pressure rise value of gas in the fan, including static pressure, dynamic pressure and total pressure; Power refers to the input power of the fan, namely shaft power. The ratio of effective power of fan to shaft power is called efficiency. Wet dedusting equipment Price The total pressure efficiency of fan can reach 90%. Fans are widely used for ventilation, dust discharge and cooling of factories, mines, tunnels, cooling towers, vehicles, ships and buildings; Ventilation and induced draft of boiler and industrial furnace; Cooling and ventilation in air conditioning equipment and household appliances; Drying and selection of grain; Wind source of wind tunnel and inflation and propulsion of hovercraft. The working principle of the fan is basically the same as that of the turbine compressor, but because the gas flow rate is low and the pressure changes little, it is generally unnecessary to consider the change of gas specific volume, that is, treat the gas as an incompressible fluid
Main factors affecting the dust removal efficiency of wet electrostatic precipitator. The effect of electrostatic voltage, water volume and dust concentration on wet electrostatic precipitation efficiency is positive, that is, the dust removal efficiency increases with the increase of voltage, water volume and dust concentration. Among them, voltage has the most significant effect on dust removal efficiency, followed by water volume, and dust concentration has the least effect. The combination of static electricity and water mist can significantly improve the dust removal efficiency. The role of water in wet electrostatic precipitation. The water in wet electrostatic precipitator mainly exists as atomized water droplets. According to domestic research, water mist has a series of effects on the improvement of dust removal efficiency of wet electrostatic precipitator, major Wet dedusting equipment Main mechanism: the water mist can keep the discharge electrode clean and keep the corona vigorous; The mist particles strike the dust collecting electrode to form a thin and uniform water film, Liupanshui Wet dedusting equipment It can prevent the "secondary flying" of low specific resistance dust from tempering high specific resistance dust and prevent the occurrence of "reverse corona"; For the dust with strong viscosity, the electrode can be prevented from sticking; It is also suitable for collecting those flammable and explosive dust. The water mist is sprayed directly to the discharge electrode and corona area, and the discharge electrode also acts as an atomizer. The same power supply can realize corona discharge, water atomization, water mist and dust particle charging, realizing the organic combination of static electricity and water mist. The water mist is directly sprayed to the discharge electrode, which has a high charge. The collision interception, adsorption and coagulation of water mist with high charge mass ratio in the electric field can greatly improve the dust removal efficiency. The water mist strikes the dust collecting electrode to form water flow down, so that the dust collecting electrode is always kept clean, eliminating the vibrating device, and avoiding a series of problems caused by vibrating dust removal in dry dust removal. In the method of spraying water mist to the discharge electrode and corona area to further atomize the water mist, the static electricity does not directly contact the spray device, so there is almost no insulation problem. This method is completely different from the dedusting technology of "corona discharge atomizes water". The latter is almost impossible to insulate due to the direct contact between water and electricity, and it is actually difficult to achieve industrial application. The barbed electrode can produce a strong electrostatic field, and has a good corona discharge capacity. The electrostatic and water mist work together, and has a high dust removal efficiency
3. When installing Type C and Type B, ensure that the two pulley positions are on the same plane, and the flatness tolerance is 0.5mm. 4. When installing Type D, use a dial indicator and feeler gauge to measure the coaxiality of the fan spindle and motor spindle and the parallelism of both ends of the coupling. The coaxiality tolerance of two shafts is 0.2mm, the parallelism tolerance of both ends of the coupling is 0.2mm, and the spacing between two planes of the coupling is 5 to 8mm. 5. After the fan is installed, move the rotor with hand or lever to check whether it is too tight or collided. The test run can be carried out without overtightening or collision. 6. After the motor is installed, the belt pulley or coupling guard shall be installed. If the air inlet is not connected to the air inlet pipe, the guard net or other safety devices (provided by the user) shall also be provided. 7. Other parts shall be installed according to the corresponding positions in the drawing. 8. Add N46 (ISO VG46, 30) in summer and N32 (ISO VG32, 20) in winter. The oil level should be at 1/2 of the oil window.
major Wet dedusting equipment Fans can be divided into axial flow fans, centrifugal fans and diagonal flow (mixed flow) fans according to the flow direction after the airflow enters the impeller. Fans are divided into press in local fans (hereinafter referred to as press in 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 (hereinafter referred to as extraction fans) according to their purposes. Wet dedusting equipment Price Fans can also be divided into single-stage, two-stage or multi-stage pressurization fans according to the form of pressurization. For example, 4-72 is single-stage pressurization, and high-end fan is multi-stage pressurization fan. Fans can be divided into axial flow fans, mixed flow fans, roof fans, air conditioning fans, etc. Fan can be divided into negative pressure fan, low pressure fan, medium pressure fan and high pressure fan according to pressure. According to the outlet pressure (pressure rise), it can be divided into: ventilator (≤ 15000 Pa), blower (15-350000 Pa), compressor (≥ 350000 Pa)
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. （
