Diverters, types

The cutters in use in mechanical sampling are divided into diverter types and bucket types. Both types are used to cut a stream falling due to gravity off the end of a conveyor belt or from the discharge end of a pneumatic conveying pipe or a chute. 

The bucket-type cutters have the advantage of being able to collect and transport the sample laterally, without the loss of headroom they collect and hold the sample, however, and thus allow material build-up within the bucket if the powder is a little sticky. Another disadvantage is that, whilst the mass of the diverter-type cutter remains the same during its traverse across the falling stream, the mass of the bucket cutter increases rapidly and the drive systems must be powerful enough to maintain its speed. 

Out of these two, commonly transient diverter types are often used in I C... 

Short details of various components used in a typical transient diverter type SPD has... 

Another type of automatic sampler is the Woodside sampler, which consists of chains carrying small cups (Figure 13.6). The chains pass through the grain stream, the buckets fill and empty directly into a hopper, from which the sample can be transported by gravity pneumatically or manually into the test laboratory. The size of sample delivered by a Woodside sampler can be regulated by the number and size of the cups. The modern tendency is to move toward the diverter-type sampler. These are generally more flexible than the Woodside sampler. For example, peas are very hard and more or less round, and tend to bounce into and out of the small cups of a Woodside sampler. Diverter samples are not subject to this source of error. 

Today, benzoic acid (flakes or fines) is probably the most broadly applicable diverter type, as it is soluble in water and oil and sublimes in gas. Benzoic acid may also be dissolved in water (as ammonium benzoate) and in alcohol. When contacted by water at reservoir pH, benzoic acid dissolved in either aqueous or alcohol solution is precipitated as a smaller, softer, and more easily deformed partide. This form of benzoic acid diverter may be used with more confidence in gravel pack completions, for example. 

Perhaps the greatest need in the acidizing industry is for an effective, nondamaging, inexpensive diverter or acid placement method. Inasmuch as treatment conditions are so different from one well to another, such a diverter is probably a fantasy. However, it is possible to continue improving on existing methods and, certainly, on well assessment and selection of acid placement technique. For commercially available chemical diverter types currently in use and widely accepted industry guidelines, see table 6-9. 

Arresters or diverters are generally of the following types and the choice between them will depend upon the power frequency system voltage, characteristics of the voltage surges and the grounding system, i.e. 

Baffle separators of the Venetian blind, V, W, and wave types are widely used for spray removal. They have small space requirements and low pressure drops. They operate by diverting the gas stream and ejecting the droplets onto the collector baffles. Efficiencies of single stages may be only 40-60%, but by adding multiple stages, efficiencies approaching 100% may be obtained. 

The adsorbers are usually built of steel, and may be lagged or left unlagged the horizontal type is shown in Figure 28. The vapor-laden air is fed by the blower into one adsorber which contains a bed of 6- to 8-mesh activated carbon granules 12 to 30 inches thick. The air velocity through the bed is 40 to 90 feet per minute. The carbon particles retain the vapor only the denuded air reaches the exit, and then the exhaust line. The adsorption is allowed to continue until the carbon is saturated, when the vapor-laden air is diverted to the second adsorber, while the first adsorber receives low-pressure steam fed in below the carbon bed. The vapor is reformed and carried out by the steam. The two are condensed and if the solvent is not miscible with water, it may be decanted continuously while the water is run off similarly. After a period which may be approximately 30 or 60 minutes, all the vapor has been removed, the adsorbing power of the charcoal has been restored, and the adsorber is ready to function again, while adsorber No. 2 is steamed in turn. 

In the case of atmospheric type burners, a draft diverter is required on the appliance (in addition to the flue outlet). 

More commonly, a fraction, based on chemical type, molecular weight or volatility, is heart-cut from the eluent of the primary column and introduced into a secondary column for more detailed analysis. If the same mobile phase is used in both dimensions, fractions may be diverted by means of pressure changes-an approach first used in 1968 in GC-GC by Deans (35), and applied by Davies et al. in SFC-SFC (36). If the mobile phases are different, valves are employed, and special... 

Electronic ratio controller. In this type of controller, a proportion of both gas and air is diverted through a bypass in which a thermistor sensor measures the flow. The air and gas flows can be compared and the ratio calculated and displayed. A ratio control valve in the air or gas supply, depending on whether the mode of operation is gas- or air-led, will automatically restore a deviation from the pre-set ratio. The electronic controller maintains ratio over a 19 1 turndown. The principle of operation is based on mass flow, so that it can be used with preheated air in recuperative systems. 

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