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Specification in Design

Aug 11, 2014



- Define the meaning of a specification in design.
- Analyzing in specification >> Centrifugal pump equipment

  • The specification is probably the easiest part of the design process. It is one that pupils tend to neglect or write incorrectly. It is usually a list of points, with each point referring to the research work. Have been used historically in public contracting for buildings, highways and other public works. Specification in Design
  • Specification must included : Drawings Dimensions Environmental Factors Cost Maintenance Ergonomic Factors Aesthetic Factors (Beauty)
  • Documentation Quality Safety Description Needed for :
  • Analyzing in Specification Pump Equipment
  • Transfer of liquid from one place to another place. e.g. water from an underground aquifer into a water storage tank. Circulate liquid around a system. e.g. cooling water or lubricants through machines and equipment Purposes of Pump
  • Centrifugal Pump
  • A sub-class of dynamic axisymmetric work-absorbing turbo machinery. Used to transport fluids by the conversion of rotational kinetic energy to the hydrodynamic energy of the fluid flow. The rotational energy typically comes from an engine or electric motor. The fluid enters the pump impeller along or near to the rotating axis and is accelerated by the impeller, flowing radially outward into a diffuser or volute chamber (casing), from where it exits. Introduction
  • Main Components
  • 1. Impeller It consists of a series of backward curved vanes. The impeller is mounted on a shaft which is connected to the shaft of an electric motor. 2. Casing Provide a pressure boundary for the pump and contains channels to properly direct the suction and discharge flow. 3. Suction pipe with a foot valve and a strainer A pipe whose one end is connected to the inlet of the pump and other end dips into water in a sump 4. Delivery pipe A pipe whose one end is connected to the outlet of the pump and other end delivers the water at a required height
  • Centrifugal pump works by the conversion of the rotational kinetic energy, typically from an electric motor or turbine to an increased static fluid pressure. Centrifugal pump works by spinning water with propellers inside an housing or casing. During the spinning, pressure builds outwards. The pressure propels the water through the desired path. How it work?
  • Cavitation - The net positive suction head (NPSH) of the system is too low for the selected pump Wear of the Impeller - Can be worsened by suspended solids Corrosion inside the pump caused by the fluid properties Overheating due to low flow Leakage along rotating shaft Lack of prime - centrifugal pumps must be filled (with the fluid to be pumped) in order to operate Surge. Problems