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How to carry out the technological transformation of pumping stations
Technical renovation of pumping station Many of the mechanical and electrical pumping and drainage facilities in our country were built in the 1960s and 1970s or before. After several decades of operation, some pumping stations became over-service, ill-operated and the equipment aged seriously, resulting in low efficiency of the pumping station, High energy consumption, operating costs and more. At present it is difficult to come up with a lot of money on the aging of the pump station reconstruction or a comprehensive renovation. Therefore, the technical transformation of the pump station to improve pump efficiency is an important way to save money in the pump station management macro. Technical transformation of pumping station is based on the original pumping station project and facilities, through the investigation and research, pumping station testing, overall arrangements, the use of mechanical and electrical drainage irrigation of new technologies, new processes, new methods, advanced equipment, and comprehensively improve the level of technical and economic indicators , To ensure the ability to supply and discharge, give full play to engineering benefits, economic benefits, social benefits and environmental benefits of the pumping station facilities to achieve the expansion of the main content of the reproduction. First, the basic technical and technological transformation of pumping station Technical transformation of pumping station is a technical work involving a wide range of technical and economic conditions is more complicated, it is necessary to conscientiously do a good job of investigation and study, comprehensive planning and reasonable arrangements. Pumping station testing is an important part of technological transformation of pumping stations, and its test data is the basis of technological transformation of pumping stations. Pumping station technical transformation before and after the field test must be carried out. Technical transformation of pumping station engineering includes pumping station and water supply and drainage area in two parts. The water supply and drainage area is the condition that the pump station is established, and the pump station is also the guarantee for the water supply and drainage area. Pumping station technical transformation program to be fully technical and economic comparative proof, the selection of the optimal program, with the least investment, to obtain the best economic results. According to the requirements of "General Rules and Regulations for Pumping Station Technical Transformation" (141-85), the main technical and economic indexes of pumping stations after technological transformation shall meet the following standards: Water supply and drainage (1) The water discharge flow shall meet the standards of water supply and drainage for improving design. ⑵. For power supply and drainage stations. Due to different pumping station types, unit capacity and net head lift, pumping station efficiency should meet different standards: large pumping stations, large pumping stations and high-lift pumping stations, with pumping efficiency ≥65%; medium- and small-sized pumping stations Pumping station efficiency ≥54.4%. Low-lift pump station (<3), the pumping station efficiency ≥ 50%. ⑶ for the internal combustion engine supply and drainage pumping station, requiring its energy consumption reached ≤ 1.35, equivalent to pumping efficiency ≥ 54.8%. In the water supply area where the reconstruction station is located, comprehensive planning and improvement of the supporting facilities of the canal system and its ancillary buildings shall be adopted. Effective measures for seepage prevention and leakage prevention shall be taken in accordance with local conditions so as to improve the utilization rate of canal water. Irrigation pump station canal water use coefficient should generally reach: large irrigation area ≥ 0.6; medium irrigation area ≥ 0.65; small irrigation area ≥ 0.70. In the northern water-scarce regions, higher demands should be made. Second, pumping station technical transformation measures As mentioned earlier in this chapter, pumping station efficiency is to reflect the overall efficiency of the power machine, transmission, pumps, piping, access to various parts of the pool efficiency. Therefore, to improve pump efficiency and reduce pump energy consumption, it is necessary to carry out technological transformation in the above five aspects to improve its efficiency, which is an important way to improve pump efficiency. (A) to improve the efficiency of the power machine To improve the power machine efficiency, in addition to the power machine (motor, diesel engine) design, manufacturing and other areas to be improved, the use of units should pay attention to the following questions. A reasonable matching power machine and pump must be reasonable in power matching. Auxiliary power reserve factor should not be too large to meet the power machine is not overloaded in operation. Due to lack of motor load, the motor efficiency to reduce, increasing the motor energy consumption. At the same time the motor power factor is also reduced, increasing the loss of transmission lines and transformers. Motor efficiency and power factor change with load, as listed in Table 12-5-1. When the diesel engine is under load, the fuel consumption rate increases, as listed in 12-5-2. Obviously, motivation and economy are also poor. General motor load rate ≥ 0.7 more economical, when ≤ 0.5, should be adjusted or replacement requirements. Can take the following measures: â‘´. In the technical transformation of pumping station. Motor should be adjusted to support the focus should not be replaced with a motor to improve pump efficiency. If you must replace, to replace the appropriate motor model, size, capacity. ⑵. Load less than 40% of the motor should be prioritized in the original motor. Adjust the motor speed, without reducing the transmission efficiency under the premise of the pumping station at high efficiency. ⑶. For the test found that excessive power of individual motors, motor efficiency testing should be conducted before deciding whether to phase out the update. Change the motor winding wiring method for the actual load motor rated load is much smaller than the case, but can not be replaced at a time when the smaller capacity of the motor, the delta connection of the motor is changed to the connection. To make it a reasonable package, to achieve good energy-saving effect. For the diesel engine unit, if the pump that has been put into operation does not support the diesel engine, it can change the speed of the diesel engine according to the change of the load, so that the diesel engine can work in the economic operation area. Such as improper selection of pumps. Making the actual motor load rate is less than the rated load, the motor speed control method should be used. Under the premise of not reducing the transmission efficiency, the pump is operated in a high-efficiency zone so as to improve the device efficiency under various operating conditions and achieve a good energy-saving effect. Motor speed control methods are to change the motor stator voltage speed, change the motor stator pole speed, change the motor rotor resistance speed, change the power slip speed speed cascade speed and frequency control. Variable pole speed is achieved by changing the motor pole pairs to adjust the speed of the purpose, it can be constant torque speed characteristics or constant power speed characteristics. This speed control mode has the advantages of simple control, convenient maintenance, low price and the like; the disadvantage is that there is a step speed regulation, and the stator windings have more taps and the wiring is more complicated. Frequency control by changing the frequency of the power to achieve the purpose of adjusting the motor speed. The main advantage of frequency control is the speed range, speed control of the smooth, the frequency can be smoothly transferred to the rated speed corresponding to the frequency, such as the motor structure allows the rated speed up; and has sufficient mechanical properties, Frequency can be achieved when the constant torque or constant power speed to adapt to different load requirements. Therefore, the frequency control is the most promising asynchronous motor speed control method. The disadvantage of variable frequency speed control is the need to have a power inverter device (called the inverter), the higher the price. Change the slip of the speed control by adjusting the slip of the motor to achieve the purpose of speed. This method is only suitable for asynchronous motor. The synchronous speed constant, by adjusting the motor stator voltage, cascade, change the string winding motor rotor circuit additional resistance and other methods to achieve speed. The common characteristic of the method of adjusting the slip speed is that the efficiency is low and the speed of the speed regulation is poor. In the technological transformation of the pumping station, an appropriate speed regulation scheme is selected according to the specific conditions of the pumping station and the characteristics of various speed regulation methods. For the diesel engine pumping unit, if the pump that has been put into operation is not suitable, in addition to replacing the appropriate diesel engine model, the engine speed may be changed according to the change of the load, so that the diesel engine can work in the economy zone where the fuel consumption rate is relatively small. 2. To strengthen the maintenance of regular maintenance motor to improve the motor running mechanical properties, reduce mechanical losses, can increase the natural power factor. For long-term insulation aging motor, insulation treatment, and can improve the reliability of the operation of the electric machine. Diesel engine to strengthen the maintenance management. In order to reduce mechanical friction loss, to ensure that the relative movement between the appropriate parts with the gap, to choose the right lubricant, to maintain the normal temperature of the lubricant. In order to improve the combustion efficiency of diesel engine, the oil should be supplied at the best advance angle in operation. To improve the spray quality, it is necessary to adjust the gas phase and control the cooling water temperature as required. (B) to improve transmission efficiency Transmission efficiency for the pump shaft power and power output ratio of the percentage. The choice of transmission mode is reasonable and directly affect the transmission efficiency. When the speed of the power machine can meet the operating conditions of the pump, ie, when the speed is equal to or close to (the difference can not exceed 2%), the indirect drive should be changed to the direct drive] and the indirect drive to the direct drive. When the pump conditions change, the power machine can not speed, the direct drive can be changed to indirect drive. Direct drive to indirect drive, the transmission efficiency will decline, but the pump efficiency, pipe efficiency can be improved. However, it can only be used if the efficiency of the device is to be increased. Therefore, when the direct drive to indirect drive, must ensure that pump station efficiency has increased, in order to obtain good energy-saving effect. In the belt drive, should usually avoid the use of cross, semi-cross drive. Transmission installation accuracy and use is correct, but also directly affect the transmission efficiency. Such as direct drive coupling is not the heart, will result in lower transmission efficiency. Transmission belt drive shaft distance is too small or too large, and the belt tension is too tight or too loose will affect the transmission efficiency. If the belt is installed correctly, the maximum efficiency of the flat belt can reach 98%. V-belt up to 94%; if not installed properly, slipping more serious, flat belt efficiency will be reduced to 94%, the V-belt can be reduced to 90%, this will cause greater energy loss. In order to reduce slipping phenomenon, to achieve accurate transmission ratio, and can improve transmission efficiency, synchronous toothed belt can be used. 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