Retrofit Design Of Building Water Supply System

Because people’s increasing needs for water and more strict demands on quality of water supply, the weaknesses of traditional ways of secondary water supply such as having difficult in changing the water pressure, secondary pollution problems have become increasingly prominent. However, due to historical reasons, there are still many buildings that use traditional secondary water supply technology. Retrofitting these buildings which use the old secondary water supply is an effective means of improving the quality of water supply. This article deals with the transformation of the target due to improper design of water supply system, lead to water points in the low position having excessive pressure and in high position having no enough pressure. So its network of waterways should be redesigned, the problems including water mains’arrangement, selection of the pressure control point, calculation and selection of hydraulic supply equipment and materials problems were discussed; Then, making sure the constant pressure water supply would be main ways after transformation, and the main circuit and control circuit of the new system were designed. The entire system centers on PLC, and the PLC’s I/O points were given in the design, besides we select the relevant components. Then determine the pumps’running plan, and accordingly design the control flow. Includes the analysis of the pump running program, determination of the frequency limit, the pump stops open selection criterion, which determines the complete control scheme of the system, also writing the program according to the control plan. Finally, the engineering and the estimated cost of the entire project, and describes the current working situation about the system, lay the foundation for future improvements.