Figure 1. Schematic diagram of pumping stations and pipelines. Figure 2. Vertical centrifugal turbine pump. Figure 3. High velocity flame spraying of wear resistant WC material on the outer surface of the impeller. Table 1: Pumping Station Equipment Table 2: Average sand content in the river (kg / m3) Water supply to areas that need water is not always straightforward, and water supply in Shanxi Province in northern China is no exception. One of the difficulties is to raise the water from the Yellow River through five pumping stations to 630 meters. Running continuously for 24 hours (7300 hours) for 10 months each year requires that the pump be protected from wear as much as possible. Ebara accepted the challenge of the Huanghe section of Shanxi's Wangjiazhai project. Shanxi Province is located in the central and northern part of China. Generally, precipitation is less. 70% of the area is covered by hills, plains and sand dunes. Rainfall is not easy to collect. The annual per capita water supply is 17% of the total in China, down to 3% of the world average. The steel and petrochemical industries in Shanxi Province, the capital of Taiyuan, both rely on groundwater, but only half the amount of water is available. In this case of long-term shortage, Shanxi Wangjiazhai Yellow River project started in 1993, known as the "lifeline project." Water was taken from Wangjiazhai Dam, 90 meters high, built in the middle of the Yellow River. The entire project is completed each year from the dam to supply Taiyuan and Datong 1.2 billion tons of water, which accounts for about 3% of the Yellow River water. Figure 1 shows the schematic of the pump station and the pipe. Three of the five pumping stations are built on the main dam to tributary and the other two are on the southern main line. Five installed pumping stations are used to supply water to destinations in order to overcome the huge height difference of 630 meters between pipes. Pumping facilities are summarized in Table 1. The pump installed is a vertical centrifugal turbine pump (Figure 2 and Figure 3). Spiral volute made of welded steel. Despite its size, the entire pump is completely exposed rather than embedded in the concrete floor, and the volute and support ring are bolted so that the components can be disassembled for annual wear maintenance. These pumps are among the highest-lift, highest-flow, single-stage pumps in the world. In addition to their high efficiency and high suction performance, these pumps must also have sufficient hydraulic properties to withstand grit erosion of the Yellow River water, with high levels of sand in the Yellow River water. These pumps have several properties that make them well suited for this application, including: ◆ Spiral volute is fully exposed. ◆ The volute and support ring (diffuser) are bolted. ◆ The impeller is attached to the pump's bevel shaft to facilitate the removal of components during annual maintenance. Impellers use three hard finishes to resist wear. ◆ The innovation of the volute can prevent the expansion and contraction of the equipment due to the temperature difference between summer and winter. ◆ Turbine bracket is equipped with thrust bearing, which can withstand the thrust of water up to 6300 kN on the volute. The helical casing of these vertical pumps is completely exposed and bolted to the supporting impeller. This type of hydraulic machinery with a large flow rate has never been used in this way. Two hydraulic modes were used during installation: one for the high lift pump and the other for the low lift pump. The impeller was redesigned using the Reversal Design and the CFD (Computer Fluid Dynamics) method. This method optimizes the geometry of the impeller to meet the required performance, such as flow rate and overall lift, by specifying performance goals. The performance level of the pump was confirmed after a 30-day test with a customer's testimony. Yellow River water treatment process is the most serious problem is the yellow sand contained in the river's wear and tear. The average diameter of these particles is 25 μm, which is much smaller than the usual sand and does not precipitate easily. The sand content in the river is particularly high in late summer and early autumn, and in this harsh environment the pump impeller and turbine blades run for a maximum of 10 years, the shortest months, before piercing. During the flood season in August and September, the sand content is very high and the pump will not operate. They operate 24 hours a year (7,300 hours) in 10 consecutive months and require as much wear protection as possible. This 10-month wear and tear will be repaired during a two-month standstill. Ebara Corporation processes the outer surface of the impeller using wear-resistant WC material (Figure 3). Any part of the impeller that touches the water will require further wear resistance. The impeller is closed, that is to say the inner region is closed by means of the main sleeve and the inner sleeve and forms a closed channel. Spraying of the inner region is very difficult. To this end, Ebara Corporation has developed a new compact arc spray gun that can spray the entire inner surface of the impeller. The newly developed spray gun was operated on a model simulating the impeller channel and proved to form a solid spray coating. At the same time, the spray and melt of the WC alloy is successfully applied to a sufficient number of sites to give it abrasion and cavitation resistance. Such work is needed in the factory as well as on-site maintenance. Postscript In January 1999, Ebara Corporation received an order for the project, and many engineering customers were invited to conduct in-depth and detailed discussions and consultations for as long as eight months. In May 2006, Ebara Company supplied a large, wear-resistant, high-flow pump to one of the largest pumping stations in the world. When the water begins to flow into the tributaries of the Yellow River, all the pain people feel experiencing is worth it. Shanxi Wangjiazhai Yellow River section of the first phase of construction has been completed.
Garden Lights,Outdoor Garden Lights,Led Garden Lamp,Ip66 Outdoor Lights
Arilux Worldwide International Co. Limited , https://www.ariluxworldwide.com