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Tham khảo tài liệu 'central air conditioner units and refrigeration_8', kỹ thuật - công nghệ, hoá học - dầu khí phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Simpo PDF Merge and Split Unregistered Version - http www.simpopdf.com 42. What precautions for taking water samples is common to both chemical and bacteriological analysis Sec. 25 Pars. 3 and 4 44. How far below the surface of the water in a tank should you hold the bottle when taking a sample Sec. 25 Par. 4 c 43. How is a bottle sterilized when it is to be used for chlorine testing Sec. 25 Par. 4 a 45. What type of solution should you wash your hands with after making water tests Sec. 25 Par. 7 95 Simpo PDF Merge and Split Unregistered Version - http www.simpopdf.com CHAPTER 5 Centrifugal Water Pumps IF YOU SWING a bucket of water around your head the water does not spill out because centrifugal force presses it toward the bottom of the bucket. If a number of bottomless buckets were whirled around inside a pipe and there were only one hole where water could leave the pipe each pail would throw out some of its water as it passed this hole. It would also suck up more water at the center. This is exactly how the centrifugal pump works. Instead of buckets however a centrifugal pump has vertical ribs or vanes mounted on a revolving disc. The water takes up the space between the vanes or ribs. The disc as it revolves forces water through the pump outlet to the various components the water serves. 2. In this chapter we will study installation operation and maintenance of centrifugal water pumps. 26. Installation 1. The installation of a centrifugal water pump includes laying a concrete foundation and aligning each component. The foundation should be sufficiently substantial to absorb any vibration and to form a permanent rigid support for the baseplate. Figure 80 shows a foundation and baseplate. This type of concrete foundation is important in maintaining the alignment of a directly driven unit. A mixture of 1 part cement 3 parts sand and 6 parts gravel or crushed rock is recommended. In building the foundation you should leave the top approximately 1 inch low to allow
