Some Ideas on Pumping Device Selection in the Eastern Route of South - to - North Water Diversion Project

In the east route of South-to-North Water Diversion Project, the type of water pump installation has a decisive influence on the investment in pumping station construction, operation cost, safety and reliability, management and maintenance. Now on the East Route Project of South-to-North Water Pumping device talk about a few ideas. 1. Scientific and reasonable to determine the type of pump device In the project of pumping water from the east route of South-to-North Water Diversion Project, the pump head is low, the flow rate is large, and the specific speed is higher than the number of revolutions. The pump type used is mainly axial pump (including cross-flow pump). Device performance is one of the most concerned issues in the construction of medium-sized low-lift pump stations. The type of pump device is closely related to the performance of the device. In order to scientifically and reasonably determine the type of pump unit, the following two points should be met: (1) At present, most of the large-scale pump stations built in our country are low-lift axial-flow pump stations, and the types of pump units are varied. Pump unit is included. Can be combined with large and medium-sized pumping station renovation, through the necessary prototype observation and field testing, thoroughly find out the operation characteristics of various types of pump devices and the main problems. (2) The east line pump station project has a long construction period, and it is planned to carry out prototype observation and on-site test in time for the pre-construction pumping station with special attention to the comparison with the pump test results of these pumping stations, to sum up the experiences and lessons learned, For the late construction of pump design and construction, especially the choice of type of pump device to provide a scientific and technical basis. 2. The choice of pump is the key Pump device selection In addition to select the type of pump device, the more important is to choose the pump. To choose to meet the requirements of the pump, with a number of excellent performance of the pump hydraulic model is a prerequisite. Not only to collect all the well-tested pump hydraulic models that have been built especially for well-functioning prototype pumping stations, but also to focus on the advantages and make efforts to tackle these problems. In the near future, some good water pump models should be developed and the technical indicators should not be impractical To mention too high, to take into account the energy performance and cavitation performance. To ensure the pump station using large-size pump performance is good, only a good pump hydraulic model is not enough, but also need a good manufacturing process. Based on the domestic market, we actively introduce, digest and absorb foreign advanced processing techniques, and strictly supervise and manage the manufacturing process so as to achieve excellence. Through the processing of the large-scale water pump of the East Route Project of South-to-North Water Diversion Project, the manufacturing capacity and level of the pump industry in our country have greatly increased as a whole. 3. Comprehensive consideration of technical and economic factors Pumping device selection is comprehensive, there are many factors to consider, the program to choose to consider both technology and economy. Of course, device performance is one of the most important factors, in addition, supporting the motor, transmission equipment, guide bearing, blade adjustment mechanism, speed control equipment are all requirements of unified considerations. Specific to each pumping station, the geological conditions are also factors that have to be considered, different pumps have different critical cavitation allowances, so the pump installation elevation is also different, resulting in excavation volume, foundation treatment and investment measures are not the same. For inter-basin water diversion project, we must pay attention to the optimal operation of the project, reducing the pump station into the water side of the water level changes and the rate of change, so that the pump unit often work in the highest efficiency point near the device. Due to the high range of high specific speed pump is not wide range of high efficiency, but also because of the pumping station in the eastern line of the pump running time is longer, more than 5000 hours, thereby reducing the change in device head to ensure that the device efficiency in the vicinity of the design point, with Significant energy-saving significance and better economic efficiency. The performance of the pump device includes energy performance and cavitation performance. The energy performance should be based on the device efficiency as the main evaluation index, not the high pump efficiency. The cavitation performance is very important to the long-term safe and stable operation of the high specific-rotation pump device. To maximize the cavitation than the number of revolutions, not only concerned about the design of the critical cavitation margin, we must attach great importance to the work of the pump boundary point of the critical cavitation margin. 4. To ensure safe and reliable pumping station operation Reliability is a very important issue for pumping stations with long running times. Long-term operation of the pump device to ensure the reliability and improvement from the selection stage should be specifically implemented. A complete pump unit contains many parts, only the reliability of each part is higher, the reliability of the entire pump unit may be high. If the reliability of a device is reduced due to the shorter mean time between failure (MTBF) of one or more of these components, replace it with a component with a higher reliability index or discard the device with a device with a higher reliability index Type. Such as vertical shaft pump gear gear box, the current domestic product MTBF affect the device reliability, you can use the more reliable foreign similar products to replace, but higher prices of foreign equipment, it should be based on the domestic, To strengthen cooperation with the international community as soon as possible to organize scientific research, and try their best to improve the quality of the product; Another example is the axial-flow axial pump device guide bearing is a component to reduce the reliability of the device should be strengthened research at home and abroad, if the recent difficult to improve the components Of the average time to failure, the combination of the specific circumstances of the pump station analysis, the pumping station is relatively long time for the use of other types of equipment with higher reliability; for short-run pumping station or the use of the device Pumping stations with obvious advantages of type can still adopt this type of installation, but the running cost will increase and the maintenance cycle will be shortened.