Pumps components

Vacuum system. Components associated with lowering the pressure within a mass spectrometer. A vacuum system includes not only the various pumping components but also valves, gauges, and associated electronic or other control devices the chamber in which ions are formed and detected and the vacuum envelope. 

Pumps are designed to give trouble-free operation for a long period of time. The ANSI B73.1M pumps are designed for a bearing life of no less than two years (29), and API 610 pumps for a minimum of five years (30). However, in real appHcations, a typical mean time between faUures (MTBF) is often found to be significantly less, and sometimes it is as short as a few weeks. Whereas in some instaUations the seals last from three to four years, in others these are replaced monthly. The reason for such wide variations in pump component life is often not poor pump design but equipment misappHcation. 

Low Flow Operation. The optimum operation of a pump is near the best efficiency point. Some manufacturers curves indicate the minimum allowable continuous stable flow (MCSF) limits for every pump (43). In the 1980s, the processing industry experienced a reduction in flow requirement as a result of business downturn and installation capacity downsizing. The pumping equipment, however, was generally not replaced by smaller pumps, but was forced to operate at reduced flow rates, often below allowable MCSF. This has resulted in increased failure rates and reduced pump component life. 

Two suppliers to the U.S. market are Bayer and Nippon Zeon. The estimated volume used in the United States is 500 700 t/yr. Hydrogenated nitrile mbber (HSN or HNBR) compounds compete with EKM, EVMQ, ECO, ACM, and high ACN content nitrile mbbers. Big applications include automotive timing belts, blowout preventors, drill pipe protectors, and numerous oil and fuel pump components. 

Carbon steel, low-alloy steels Transfer lines, beat exchanger shells, baffles, pump components, heat exchanger tubing, fan blades and shrouds, valves, screens, fasteners... 

Carbon steel heat exchangers, cast iron water boxes, screens, pump components, service water system piping, standpipes, fire protection systems, galvanized steel, engine components, and virtually all non-stainless ferrous components are subject to significant corrosion in oxygenated water. 

Changing the pump metallurgy to a more corrosion- and cavitation-resistant material, such as stainless steel, is a potential solution to this type of problem. Note, however, that all other cast iron pump components that have sustained graphitic corrosion should be replaced to avoid the possibility of galvanic corrosion (see Chap. 16) between retained graphitically corroded cast iron components and new components. 

Figure 12.13 Severe damage to a cast iron pump component.

Many copper alloys are also used in pumps as bushings, bearings, impellers, and gaskets. Bronzes, brasses, and other copper alloys are frequently used. Thus, pump components are often corroded. 

A paper mill was using an ANSI end suction process pump with clear water service. The motor was designed properly. The pump axial thrust bearing ran hot, failing after three months of operation. It was replaced with an identical bearing. This ran during three months and also failed. All pump components were investigated and found that they complied with the specifications. These facts eliminated the defects of materials as a cause. 

Drago, J. P. et al., In-Plant Reliability Database for Nuclear Plant Components Interim Data Report, The Pump Component, ORNL, December 1972. 

Transport proteins (channels) for chloride and zinc Vacuolar proton pump Components of synaptic vesicles to mediate the chloride flux for glutamate uptake and zinc uptake in most synaptic vesicles. Zinc transporter is homologous to endosomal and plasma membrane zinc transporters chloride transporters remain to be identified. Protein complex of more than 12 subunits. Constitutes the largest component of synaptic vesicles and establishes... 

Valve and pump components, balls for non-return valves. .. 

High-performance motor components, transmission system components, pump components... 

Weekly inspection and testing consists of visual inspection of oil and fuel levels and fire pump components, including the controller. A function test of the fire pump, driver and starting systems should be conducted. The fire pump should run for a minimum of 10 minutes for electric motor drivers and 30 minutes for other drivers. 

Lubricity is a term used to describe the ability of a fluid to minimize friction between, and damage to, surfaces in relative motion under load. Fuel helps to lubricate and prevent wear of high-pressure fuel injection pump components, especially under boundary lubrication conditions. Boundary lubrication is defined as a condition whereby friction and wear between two surfaces in relative motion are determined by the properties of the surfaces and the bulk properties of the contacting fluid. The bulk viscosity of the fuel or oil is not a critical factor under boundary lubrication conditions. 

Shearing of high-viscosity diesel fuel by the fuel injection pump can result in excessive heat buildup and distortion of the pump components. 

Table 8.4 Wear Rate of Candidate Piping and Pump Component Materials by Coal Slurries...

At this point, experiments must be performed. Experimental results for the erosive wear of the selected candidate ceramic materials in coal slurries are presented in Table 8.4. Notice that the wear rate has a very rough inverse correlation with which is consistent with some of the descriptions of erosive wear from the previous section. Any of these ceramic materials is suitable for the piping and pump components based solely on wear rate, with the lowest wear rate for SiC being the most attractive. Formability and economic criteria can be applied to assist in the final material selection. 

Phenol Formaldehyde (PF). Phenol formaldehyde is known for its high strength, stiffness, hardness and its low tendency to creep. It is also known for its high toughness, and depending on its reinforcement, it will also exhibit high toughness at low temperatures. PF also has a low coefficient of thermal expansion. Phenol formaldehyde can be compression molded, transfer molded and injection-compression molded. Typical applications for phenol formaldehyde include distributor caps, pulleys, pump components, handles for irons, etc. It should not be used in direct contact with food. 

In the mining industry, the excellent wear resistance of polyurethanes provides financial and maintenance advantages to the mines. The mechanical and chemical resistance of the polyurethanes can be used to advantage in many applications. Applications are varied and include pump components, cyclones, conveyor belt idler wheels, belt heads, and scrapers. Specialized pipes and tubes, as well as tank linings, also use polyurethane. 

As mentioned, a trap prevents condensable vapors from damaging pump components as they are removed from the vacuum system. Additionally, a trap can improve the quality of the vacuum by preventing condensable vapors and pump oil vapors from drifting back into the system. Remember that once a pump has achieved its potential vacuum, gas flow drops to zero leaving materials to drift... 

All specimen are fully wetted (Fig. 5) by the corrosive test fluid (exception R = -1 probes which were only sprayed). The surface quality of the specimen - honed resp. polished - is well comparable to the finish of real pump components. 

Further characterizations of the specimen, as residual stresses and electrochemical analysis, have not been performed as it is normally the case for real pump components. 

The reduction of downtime of the instrument (i.e., operations of pump components, injectors, and detectors) can be controlled to some degree if sample solutions are filtered and/or centrifuged the use of a 0.2- or 0.45-pm-pore-size filter is generally recommend for removal of particulates [15]. Filtration as a preventive maintenance tool for FfPLC analyses is well-documented in the ht-erature [16-18]. 

The operations of pump components, injectors, and detectors can be expected to be less troublesome when mobile phases are filtered. For HPLC applications, the 0.2-pm-pore-size filter is typically selected for removal of particu-... 

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