Specific pump types

The pump types covered by this standard can be broadly classified as overhimg, between bearings, and vertically suspended (see Figure 1-1). To aid the use of this standard, Sections 2, 3, 4, and 6 cover requirements that are applicable to two or more of these broad classifications. Section 5 is divided into 3 subsections and covers requirements unique to each of the broad classifications. Figure 1-2 shows the various specific pump types within each broad classification and lists the identification assigned to each specific type. 

Note The purchaser should consider an appropriate NPSH margin in addition to the NPSHR specified in 2.1.8 above. An NPSH margin is the NPSH that exists in excess of the pump s NPSHR (see 1.4.30). It is usually desirable to have an operating NPSH margin that is sufficient at all flows (from minimum continuous stable flow to maximum expected operating flow) to protect the pump from damage caused by flow recirculation, separation, and cavitation. The vendor should be consulted about recommended NPSH margins for the specific pump type and intended service. 

The topics of critical speed and lateral analysis are covered in each specific pump type section. 

Is type of shipment specified Specific Pump Types Yes No... 

Specific Pump Types (Continued) Is a rigging device required to facilitate removal and installation of the back pullout assembly Yes No... 

CMP slurry delivery system employing filtration for LPC eontrol should consider slurry characteristics including—abrasive type(s) and composition, LPC, PSD, wt% solids, viscosity, chemical composition and the distribution system characteristics—specific pump type and the pumping effects on slurry abrasive, pump size and speed, global distribution loop backpressure, slurry usage and replenishment cycles, slurry turnover rate and typical turnovers before consumption, filter ratings for various locations, allowable pressure drop for filters, and the slurry flow and temperature consistency needs. 

Selection of pump for a given appHcation is not a trivial task. Often more than one pump type can accomplish the required job. Thus a final choice on a pump type is often a result of personal experience and usage history. As a rule of thumb, the choice of a kinetic, such as centrifugal, or a positive displacement pump is made on the basis of the specific speed. Whereas specific speed is appHcable primarily for centrifugal but not positive displacement pumps, the US value can be used as a guide. Generally, for calculated values of specific speed, eg, nS > 10 [NS > 500), kinetic-type pumps are usually selected. For nS < 10 [NS < 500), positive displacement pumps are typically appHed. 

From the definition of specific speed (eqs. 9 and 10), it follows that reciprocating pumps operate at high pressures and low flow rates. Conversely, centrifugal pumps are appHed at lower pressures and higher flow rates. Many rotary pumps are selected for viscous Hquids having pressures equal to or less than, and capacities lower than, centrifugal pumps. However, these limits are relative and a gray area exists as some pump types cross boundaries into the domain of other types. 

Range of Operation Because of the wide variety of pump types and the number of factors which determine the selection of any one type for a specific installation, the designer must first eliminate all but those types of reasonable possibility. Since range of operation is always an important consideration. Fig. 10-26 should be of assistance. The boundaries shown for each pump type are at best approximate, as unusual applications for which the best selection contradicts the chart... 

Data Summaries of Licensee Event Reports at U.S. Commercial Nuclear Power Plants (Vanous Components) Nuclear 11209 one-fine event descriptions on specific component types failure rates and error factors Pumps, valves, diesels inverters, relays, circuit breakers (in separate reports) 100. 

For catastrophic demand-related pump failures, the variability is explained by the following factors listed in their order of importance system application, pump driver, operating mode, reactor type, pump type, and unidentified plant-specific influences. Quantitative failure rate adjustments are provided for the effects of these factors. In the case of catastrophic time-dependent pump failures, the failure rate variability is explained by three factors reactor type, pump driver, and unidentified plant-specific Influences. Point and confidence interval failure rate estimates are provided for each selected pump by considering the influential factors. Both types of estimates represent an improvement over the estimates computed exclusively from the data on each pump. The coded IPRDS data used in the analysis is provided in an appendix. A similar treatment applies to the valve data. 

Type specific speed is defined as that operating specific speed that gives the maximum efficiency for a specific pump and is the number that identifies the pump type [25]. This index number is independent of the rotative speed at which the pump is operating, because any change in speed creates a change in capacity in direct proportion and a change in head that varies as the square of the speed [25]. Practice is to true type the specific speed of the pump reasonably close to the conditions of maximum effi-... 

Table 3-26 gives the specific speeds for various centrifugal pump types. Table 3-27 gives the suction specific speed ratings for single-suction and double-suction centrifugal pumps. These tables are for pumps handling clear water. 

The pump types listed in Table 1-1 have special design characteristics and shall be furnished only when specified by the purchaser and when the manufacturer has proven experience for the specific application. Table 1-1 lists the principal special considerations for these pump types and shows in parentheses the relevant paragraph(s) of API Standard 610. 

Where requirements specific to a particular pump type in clause 8 conflict with any other clauses, requirements of clause 8 shall govern. 

Pumps come in a bewildering array of shapes, sizes, capacities, head characteristics, chemical and corrosion resistance features, materials of construction, and prime mover types. The choice of a specific pump for a specific application is best made in consultation with individual vendors who can provide detailed data about their product. Ultimately all choices are based on a cost optimization. 

Chapter 3 summarised initially the various types of vacuum pump available and the pressure ranges in which they normally operate. Subsequent sections dealt specifically with types of pump and, in some cases, to support calculations, reviewed the operating principles and characteristics. For example, aspects of oil-sealed rotary pump operation were discussed (Examples 3.1-3.5) and Roots pumps, widely used in applications where large gas loads at pressures in the rough-medium range have to be handled, were examined (Examples 3.7-3.9). 

Reference should be made to specialist texts on pumps where classifications of pump types as a function of specific speed are presented. A centrifugal pump is suggested here. 

Why are SERCA pumps exclusively located in intracellular membranes and PMCAs in the plasma membrane The answer to this question is not yet known unlike the Na+/Ca2+ exchangers, neither of the Ca2+ pump types contains a leader sequence, and no specific targeting sequences have been identified in any of the pumps. Studies with expressed chimeras consisting of recombined parts of SERCA and PMCA pumps may eventually provide an answer. 

TABLE 6.20 Pump Types Listed by Specific Speed... 

Another way to separate nitrogen compounds from hydrotreated shale oil products is by adsorption chromatography. Experiments have been conducted where basic and neutral alumina have been used to separate shale oil into specific nitrogen-type fractions. Both a pumped-flow and gravity-flow method were executed. However, it was determined that the pumped-flow procedure was better since it enabled more control over experimental parameters such as flow rate. This separation scheme could be very useful because it has been applied to shale oil products produced under different hydrotreating conditions... 

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