In the first phase of the South-to-North Water Diversion Project, a total of 21 pumping stations are to be built and 14 pumping stations built in Jiangsu Province have been utilized and partially rebuilt. Approximately 140 large-sized pumps with an impeller diameter of about 3.0m are required. The main features of these pumping stations are low lift, large single flow, long annual running time (5000h), high reliability of operation, selection of large-scale pump units should have advanced and mature, high operating efficiency, good anti-cavitation performance, stable operation Reliable features. Process manufacturing gaps Manufacturing process depends on the process and process equipment. China's large-scale pump manufacturing process means is still relatively backward, in addition to large-scale castings resin sand shape more advanced, there is generally no large-scale heat treatment and sandblasting and other post-processing equipment, and in order to reduce costs, the general large-scale castings are still traditional clay sand Process. In order to improve the roughness of inner and outer surfaces of large parts, foreign surface coating technology has been quite popular, including the surface coating can be used for the blade. This kind of craft has also started to be used in other manufacturing industries in our country. In addition, the domestic mold is usually used wood mold, and to improve the quality of the casting surface is the best plastic mold or metal mold, but the plastic mold or metal mold casting long manufacturing cycle, manufacturing costs, affecting the delivery of the pump And the price. Process equipment, foreign large pump parts are mostly CNC machining or special machining, regardless of the size of the batch, in order to improve the quality of large pump manufacturing, special tooling, clip use more, and the domestic price of pump manufacturing due to factors , Special tooling, work clamp in the pump manufacturing costs generally not be considered, so rarely used, less plane. Such as the surface of the blade NC machining, the 20th century is the best way to imitate the milling, the beginning of this century began to use the Association coordinate three-axis machining, has now been raised for the five-coordinate linkage machining, which will pump inherent quality with a quality improve. Therefore, the gap between large pump manufacturing at home and abroad is still the gap on the manufacturing equipment, as we all know, large-scale investment in equipment will result in a substantial increase in manufacturing costs, taking the domestic pump industry and turbine industry, the gap is quite large, which is why the turbine ratio The reason for the high pump price lies. The tonnage price to analyze: Turbine about 35,000 to 160,000 yuan / ton, while the pump is 15,000 ~ 25,000 yuan / ton, and sometimes even less than 15,000 yuan / ton, foreign tonnage of not less than 100,000 yuan / ton . Taking a 3m impeller diameter pump for example, weighing about 100 tons, the market price is about 1.5 million yuan, the domestic turbine price is about 4 million yuan and the foreign price is about 13 million yuan (excluding tariffs and other expenses). Hey there lovers of amazing things and crafts! Have you been looking for some practical ideas that would be of a great use in your home? I know that all of you love to buy shoes all the time no matter how many pair you already got. But what do you do with the shoe boxes? Here you can take a look at the Useful DIY Shoe Box Projects That Will Blow Your Mind. Don`t throw them away again because there are so many different things that you can make out of them and I`m sure that you are going to love every single one of the ideas I have collected for you today! Shoe Box,Sneaker Box Organizer,Shoe Storage Boxes,Stackable Storage Shoe Boxes Shenyang Meitu Artical Printing Co.,Ltd , https://www.meituprintings.com
According to the situation of large-scale domestic pumping station built, the first-stage pumping station in the east can be divided into three lifting sections to determine the basic pump type: 7.0-9.0m head Vertical guide vane mixed flow pump should be adopted; 4.0-7.0m lift should adopt vertical axial flow pump; 2.3-4.0m lift should adopt horizontal or inclined axial flow pump. According to traffic planning requirements, most of the pumping stations are 80 to 120 flows, usually about 30 in a single flow, in order to improve the reliability of the unit, usually to consider a preparation machine, therefore, the number of installed pumping stations are generally 4- For example, 5 units are under construction in Baoying Station. The total flow rate is 100 and the lift is designed to be 7.6m. The vertical flow control type guide vane pump with 33 single flow is selected. The main routes of the South-to-North Water Diversion Middle Route and the West Route are mainly self-flowing, while the eastern route requires the construction of a large pumping station cascade water supply. According to incomplete statistics, these large pumps notable features are: single flow, usually require about 30m3 / s; lifts are low, are below 10m; long run time, generally more than 5000 hours / year; technical indicators require high , While requiring high reliability, high degree of automation. The status of domestic large pump technology Large pump technology in China started in the 60s of last century, developed in the 90's, to the beginning of this century has initially formed legislation, lying, inclined three series, the impeller diameter of 1.6m, 1.8m, 2.0m, 2.5m, 2.8m, 3.0m, 3.1m, 3.2m, 3.8m, 4.0m, 4.1m, 4.5m, etc. to meet the needs of different users. As far as the specifications of large pumps are concerned, it is doubtless that we are at the forefront of the world. However, there is still a long way to go to compare the level of comprehensive manufacturing technology with that of the international advanced level. This is because the main object of long-term large-scale pump service is water conservancy system. The purpose is generally dominated by drainage and the main body of investment is the country. The benefits are indirect and social benefits. In addition, the objective operation time is relatively short and even several years One or two times, so people usually pay attention to the scale of investment in pumping station. In the bidding of the market economy is not very standard, the price plays an important role, rarely pay attention to the pump manufacturing technology to improve, due to the large pump to the power plant, municipal , Shipyards and other areas of development, pump manufacturing technology with different users, the requirements of different periods gradually increased, but the rate of increase is limited, compared with the international advanced manufacturing technology there is still a considerable gap. The gap between design technology Pump design technology has two parts: First, hydraulic components design, and second, structural design. Pump hydraulic components design China in the 20th century 80's a complete set of production, learning and research system, hydraulic components of large pump research and application can be timely and effective assurance. Since the market economy, this system has gradually collapsed, and now it no longer exists, resulting in a serious decoupling of production, learning and research of hydraulic components. This is because: First of all, hydraulic components of the initial investment is relatively large, and the resulting economic benefits are not significant, or no benefit, resulting in the basic business of hydraulic components are no longer engaged in research; Second, the tertiary institutions of the hydraulic components due to the lack of Thirdly, the market mechanism in our country does not allow enough time to carry out the preliminary research. The project approval period is long, and the approval period is long. Bidding, to determine the winning bidder to the enterprise after the manufacturing cycle is often very short, which have severely restricted the hydraulic components of the research and use; Fourth, the model of research institutions simply pursue efficiency, and the lack of fair assessment of the efficiency of institutions To assess the structure and strength of less research, resulting in practical difficulties. Therefore, at present, the level of our hydraulic components except for the high speed model can only be an international medium level.