tailieunhanh - Mechanical Science HandbooksMechanical Science Handbooks 10000 Part 11

Tham khảo tài liệu 'mechanical science handbooksmechanical science handbooks 10000 part 11', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Pumps DOE-HDBK-1018 1-93 CENTRIFUGAL PUMPS Figure 9 Multi-Stage Centrifugal Pump Centrifugal Pump Components Centrifugal pumps vary in design and construction from simple pumps with relatively few parts to extremely complicated pumps with hundreds of individual parts. Some of the most common components found in centrifugal pumps are wearing rings stuffing boxes packing and lantern rings. These components are shown in Figure 10 and described on the following pages. Wearing Rings Centrifugal pumps contain rotating impellers within stationary pump casings. To allow the impeller to rotate freely within the pump casing a small clearance is designed to be maintained between the impeller and the pump casing. To maximize the efficiency of a centrifugal pump it is necessary to minimize the amount of liquid leaking through this clearance from the high pressure or discharge side of the pump back to the low pressure or suction side. Rev. 0 Page 7 ME-03 CENTRIFUGAL PUMPS DOE-HDBK-1018 1-93 Pumps Figure 10 Centrifugal Pump Components Some wear or erosion will occur at the point where the impeller and the pump casing nearly come into contact. This wear is due to the erosion caused by liquid leaking through this tight clearance and other causes. As wear occurs the clearances become larger and the rate of leakage increases. Eventually the leakage could become unacceptably large and maintenance would be required on the pump. To minimize the cost of pump maintenance many centrifugal pumps are designed with wearing rings. Wearing rings are replaceable rings that are attached to the impeller and or the pump casing to allow a small running clearance between the impeller and the pump casing without causing wear of the actual impeller or pump casing material. These wearing rings are designed to be replaced periodically during the life of a pump and prevent the more costly replacement of the impeller or the casing. ME-03 Page 8 Rev. 0 Pumps DOE-HDBK-1018 1-93 CENTRIFUGAL PUMPS Stuffing Box