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Advantages Disadvantages <br /> Virtually any material can be used for Sampling is labor intensive and time <br /> construction. consuming. <br /> Device is inexpensive. Aeration, degasing, and turbulence occur <br /> during sampling. <br /> Sampling technician is susceptible to <br /> No external power source is required. exposure to any contaminants in the <br /> sample. <br /> Mechanism can be constructed in any size Device does not provide a continuous <br /> and shape. supply of sample. <br /> Device is easy to use and easily cleaned; <br /> requires little training for operation and <br /> little maintenance. <br /> Table S.Grab-Type Mechanism Advantages and Disadvantages <br /> B.6.7. Suction-Lift Mechanisms <br /> Suction-lift mechanisms consist of peristaltic-type pumps and centrifugal pumps that apply a <br /> vacuum which causes the liquid to be drawn upward through a suction line. Their use is <br /> generally limited to purging wells of stagnant water and sampling for inorganic analytes. Table <br /> 6 presents the advantages and disadvantages of a suction-lift mechanism and Table 7 presents <br /> the advantages and disadvantages of an inertia pump mechanism. Suction-Lift Mechanisms are <br /> not currently used by NS. <br /> Advantages Disadvantages <br /> Flow rates are easily adjustable Use is limited to situation where the liquid <br /> level is less than 25 ft below the surface. <br /> Drop in pressure of suction-lift mechanism <br /> Device has no contact with the sample. causes degasing of the sample and loss of <br /> volatiles. <br /> Device can be used in wells of any <br /> Choice of construction material is limited. <br /> diameter. <br /> High flow rates are obtainable for well Centrifugal pumps need to be primed <br /> purging. resulting in possible sample contamination. <br /> Only the tubing requires cleaning Aeration and turbulence occur with <br /> (peristaltic pumps only). centrifugal pump. <br /> Table 6.Suction-Lift Mechanism Advantages and Disadvantages <br /> Daub &Associates, Inc. Page B-15 Natural Soda LLC 2022 SAP <br />