major Centrifugal fan The reasons for failure caused by unstable operation are: improper temperature control of insulator box; The gas distributor grid is blocked, and the sediment electrode has too thick scale; Improper adjustment of water film; The oxygen content in the system exceeds the standard. ① Insufficient steam pressure and blocked steam pipeline may cause low temperature of insulator box. In the long run, the insulator surface temperature is low, and tar and dust particles accumulate, causing electric field short circuit. If the temperature of insulator box rises too fast, or the temperature changes violently during operation, the insulator will be cracked. ② Centrifugal fan company If intermittent flushing cannot be carried out as required during operation, the tar accumulated on the sediment pipe wall is difficult to be thoroughly cleaned, which, accumulated over time, not only causes excessive resistance to equipment operation, but also leads to damage to the electric field. ③ During maintenance, the water film is not adjusted as required, the water film is uneven or not thick enough, and after putting into operation, the phenomenon described in fault (4) will occur. The above situation also occurs when the water film is damaged during operation. ④ The reason for the explosion of the electrostatic precipitator is that the oxygen content in the gas exceeds the standard, the mixed explosive gas is formed in the equipment and reaches the explosion limit, and the explosion occurs when encountering electric sparks.
(3) The main faults and causes of the fan may occur during the operation of the fan. For the faults generated, the causes must be quickly identified and solved in time to prevent accidents. Faults in the Operation of 4-72-12 Centrifugal Fan and the Causes Table Fault Name Causes Severe Vibration of Bearing Box 1. The fan shaft is different from the motor shaft, and the coupling is installed askew. 2. The casing or air inlet rubs with the impeller. 3. The foundation stiffness is not enough or firm. 4. Impeller rivet is loose or wheel disc is deformed. 5. The impeller shaft disk and shaft are loose, and the coupling bolt is movable. 6. The connection between casing and bracket, bearing box and bracket, bearing box and seat is loose. 7. The air inlet and outlet pipes of the fan are poorly installed, causing vibration. 8. The rotor is unbalanced. Bearing temperature rise is too high 1. The bearing box vibrates violently. 2. The lubricating grease is poor in quality, deteriorated or overfilled, or contains dust, sand, dirt and other impurities. 3. The tightening force of connecting bolts of bearing cover seat is too large or too small. 4. The shaft and rolling bearing are installed askew, and the front and rear bearings are not concentric. 5. The rolling bearing is damaged. The motor current is too high and the temperature rise is too high. 1. The throttle valve in the air inlet pipe is not closed tightly when driving. 2. The flow exceeds the specified value, or the air duct leaks. 3. The gas density conveyed by the fan is too high. 4. The input voltage of the motor is too low or the power supply is cut off individually. 5. The coupling is improperly connected, the leather ring is too tight or the gap is uneven. 6. Affected by the violent vibration of the bearing box. 7. Affected by deterioration or failure of parallel fans. When the belt slides down, the two pulleys are not in the same plane with each other. Belt runout The distance between two pulleys is too close or the belt is too long.
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.
The fan is allowed to start at full voltage or at reduced voltage, but it should be noted that the current at full voltage starting is about 5~7 times the rated current, and the reduced voltage starting torque is proportional to the square of the current. When the grid capacity is insufficient, the reduced voltage starting should be used. (When the power is greater than 11KW, it is advisable to adopt the step-down starting.) When the fan is in test run, Centrifugal fan company Carefully read the product manual and check whether the wiring method is consistent with the wiring diagram; Carefully check whether the working voltage of the power supply to the fan meets the requirements, whether the power supply is out of phase or in phase, and whether the capacity of the electrical components provided meets the requirements. During commissioning, the number of people shall not be less than two. One person shall control the power supply and the other person shall observe the operation of the fan. If any abnormality is found, stop the machine immediately for inspection; First, check whether the rotation direction is correct; After the fan starts to run, immediately check whether the running current is balanced and whether the current exceeds the rated current; major Centrifugal fan If there is no normal phenomenon, stop the machine for inspection. After five minutes of operation, stop the machine to check whether the fan is abnormal, and start the machine again after confirming that there is no abnormal phenomenon. When the two speed fan is tested, start the low speed fan first and check whether the rotation direction is correct; When starting the high-speed train, the fan must be stopped before starting to prevent the switch tripping and motor damage caused by high-speed reverse rotation. When the fan reaches the normal speed, check whether the input current of the fan is normal, and the operating current of the fan cannot exceed its rated current. If the operating current exceeds its rated current, check whether the voltage supplied to the fan is normal. The motor power required by the fan refers to the higher power required for centrifugal fan and fan box when the air inlet is fully open under certain working conditions. If the air inlet is fully opened for operation, the motor may be damaged. During fan commissioning, it is better to close the valve on the inlet or outlet pipeline of the fan, open the valve gradually after operation until the required working condition is reached, and pay attention to whether the operating current of the fan exceeds the rated current
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 Centrifugal fan 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, Liling Centrifugal fan 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
The wet electrostatic precipitator is a new kind of dust removal equipment used to treat micro dust and micro particles, major Centrifugal fan It is mainly used to remove dust, acid mist, water droplets, aerosols, odor, PM2.5 and other harmful substances in humid gases, and is an ideal equipment for controlling atmospheric dust pollution. The wet electrostatic precipitator is usually referred to as WESP, which has the same basic principle as the dry electrostatic precipitator. It goes through three stages: charging, collection and dust removal. The principle of wet electrostatic precipitator is the same as that of dry electrostatic precipitator, Liling Centrifugal fan The dust is charged by high-voltage corona discharge, and the charged dust reaches the dust collecting plate/tube under the action of electric field force. The dry electrostatic precipitator mainly deals with dry gas with very low water content, while the wet electrostatic precipitator mainly deals with wet gas with high water content or even saturation. There is a big difference between WESP and DESP in the way of removing the dust collected on the dust collecting plate/pipe. The dry electrostatic precipitator generally uses mechanical rapping or acoustic cleaning to remove the dust on the electrode, while the wet electrostatic precipitator uses regular flushing to remove the dust along with the flow of flushing fluid