Pumps materials

Pump Materials of Construction In the (memical industry, the selection of pump materials of construction is dictated by considerations of corrosion, erosion, personnel safety, and liquid contamination. The experience of pump manufacturers is often valuable in selecting materi s. See section on materials. 

Pump materials shall he selected to suit the particular service requirements. 

All Duron Metal. AU pump materials shall he Duron metal. Shaft shall he 1045 steel, with 316 SS sleeve. 316 SS metal impeller optional. 

All 20 Stainless Steel. All pump materials shall he 20 SS stainless steel. Shaft shall he 316 SS, with 20 SS sleeve. 

Designing vessels for full vacuum eliminates the risk of vessel collapse due to vacuum. Many storage and transport vessels have been imploded by pumping material out with the vents closed. 

Classification of pump materials shall be in accordance with the following items a through c ... 

Alloy 20 or Monel pump material and dual mechanical seals should be used with a pressurized seal oil system. 

Now let us look at the systems and the components of the systems. Reports in the field are virtually mute on many small but annoying problems, which almost invariably accompany the operation of seawater RO systems. Here are some which have plagued us, starting with the pumps. I will not identify manufacturers, as I have avoided reference to any in this writeup. It is not my objective to accuse anyone. I just offer these comments in the hope to encourage those who I hope are aware of their product problems in the field and failures to rectify those for the benefit of all. I feel that considerably greater attention must be placed on pumps and pump materials selection for seawater RO use in order to improve reliability, simplify maintenance, and reduce failure frequency in the pump operations, and in turn improve on the RO system water supply capability. 

UNS N08007 or Ni-Cu alloy pump material should be used. 

Pumps. Materials of construction for pumps vary with the type of service. At lower velocities, sea water has been handled successfully in pumps using casings made from cast iron. Cast iron containing a few per cent of nickel is reported to be finer grained and to have smaller graphite flakes. This may explain its superior performance for sea-water service compared with ordinary cast iron. 

Dantzer, P., F. Meubier (1988), What Materials to Use in Hydride Chemical Heat Pumps , Materials Science Forum, 31,1-18. 

Ml AISI 316 Stainless Steel All pump materials shall be AISI 316... 

Ml CD-4MCU. All pump materials shall be CD-4MCu. Shaft shall... 

Figure 13.12. Energy Transduction by Membrane Proteins. The Na+-K+ ATPase converts the free energy of phosphoryl transfer into the free energy of aNa+ ion gradient. The ion gradient can then be used to pump materials into the cell, through the action of a secondary transporter such as the Na+-glucose symporter.

Pumps for the evaporation plant must stand up under the hot glycerol-brine solution and are also generally of the centrifugal design. Cast stainless steels (CP8M alloy) are often used for this application, but a superior material for pumps is a chromium-nickel-copper-molybdenum stainless steel known as CD M, which should be considered when choosing the pump material. The extra cost is usually not significant. 

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