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Standard Methods for Examination of Water & Wastewater_3

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Các vị trí nơi máy bơm được cài đặt một trạm bơm. Có thể là chỉ có một máy bơm, máy bơm nhiều. Tùy thuộc vào kết quả mong muốn, những máy bơm có thể được kết nối song song hoặc trong loạt. Trong kết nối song song, thải của tất cả các máy bơm được kết hợp thành một. | 4 Pumping Pumping is a unit operation that is used to move fluid from one point to another. This chapter discusses various topics of this important unit operation relevant to the physical treatment of water and wastewater. These topics include pumping stations and various types of pumps total developed head pump scaling laws pump characteristics best operating efficiency pump specific speed pumping station heads net positive suction head and deep-well pumps and pumping station head analysis. 4.1 PUMPING STATIONS AND TYPES OF PUMPS The location where pumps are installed is a pumping station. There may be only one pump or several pumps. Depending on the desired results the pumps may be connected in parallel or in series. In parallel connection the discharges of all the pumps are combined into one. Thus pumps connected in parallel increases the discharge from the pumping station. On the other hand in series connection the discharge of the first pump becomes the input of the second pump and the discharge of the second pump becomes the input of the third pump and so on. Clearly in this mode of operation the head built up by the first pump is added to the head built up by the second pump and the head built up by the second pump is added to the head built by the third pump and so on to obtain the total head developed in the system. Thus pumps connected in series increase the total head output from a pumping station by adding the heads of all pumps. Although the total head output is increased the total output discharge from the whole assembly is just the same input to the first pump. Figure 4.1 shows section and plan views of a sewage pumping station indicating the parallel type of connection. The discharges from each of the three pumps are conveyed into a common manifold pipe. In the manifold the discharges are added. As indicated in the drawing a manifold pipe has one or more pipes connected to it. Figure 4.2 shows a schematic of pumps connected in series. As indicated .