There are several factors that should be taken into consideration when pumping

There are several factors that should be taken into

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river or sea water or man-made, fabricated piping systems may also introduce solids in the fluid from weld slag and pipe burn. There are several factors that should be taken into consideration when pumping fluids with particles found in the flow: the hardness of the particle, the concentration of the particles, size distribution, geometry, velocity of the fluid flow, and the angle of the fluid impingement. Particle velocity is an important component in the degree of damage that occurs in a pump handling slurries. The pump gives the entrained particle kinetic energy that, when striking a hard surface, erodes the material. In addition, the pump’s ability to absorb the kinetic energy of the particle, based on the material’s hardness and/or resilience, also plays a role in the amount of material loss upon impact. The characteristic feature of erosion damage due to solid particles striking the pump is usually recognizable; however, sometimes it is mistaken as corrosion-erosion or vice versa. In cases like this, improper diagnosis will lead to an improper solution to the problem [11]. 4.2 Corrosion Corrosion is the chemical alteration of a material. Corrosion comes in 7 different forms (general, dealloying, galvanic, stress corrosion cracking, hydrogen embrittlement, microbiologically induced corrosion, intergranular corrosion), some of which are more common than others. General corrosion occurs without any localization of attack. This type of corrosion occurs on metals or alloys that do not develop an effective passive film on the surface. Corrosion usually occurs as a result of oxidation, and metal oxide is produced. Most often, pumps made with carbon steels, cast iron and copper base alloys experience this type of corrosion. Carbon
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10 steel, which is sometimes used in pump applications, does not develop a protective oxide film and will corrode at a rate that is dependent upon factors such as temperature, oxygen content, pH, fluid chemistry, and the velocity of the fluid. For most pump applications, since the corrosion rate is too high for this material to provide a useful life, a form of protective coating is placed over the steel to prevent corrosion [11]. Dealloying, the second type of corrosion, is a result of the removal of one phase from a multi-phase alloy or one element from a material. One of the most common cases of dealloying found in pumps is the graphitic corrosion of gray cast iron. Due to its low cost, easiness to machine, and its versatility, it is used in a wide variety of applications in the waterworks industry and in the pump industry. Although this type of corrosion is found in both fresh water and salt water, the high conductivity of salt water increases the corrosion rate. However, the corrosion rate can be slowed down if the water has a high mineral content, since the minerals tend to plug up the apertures left behind from the de-graphitization, sealing off the base metal from exposure to the passing fluid, and thus reducing the corrosion rate [11].
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