Guide columns

Table 10.16 Chromatographic column guide for Century organic vapour analyser...

The column, guided on a dovetail slide, carries the wheelhead at its top end and contains the motor and belt drive to the wheel spindle. The column and wheelhead are raised and lowered through a screw and nut from a handwheel on the front of the machine. A telescopic guard is fitted to prevent grinding dust coming between the slide surfaces. 

Horizontal keyways located alongside the upper portion of the column guide the vessel during thermal expansion and contraction of the Reactor Coolant System and maintain the vessel centerline. 

Beyond certain limits increase of the reflux ratio does not appreciably increase the separating power or efficiency of the column. As a rough guide, if the column has an efficiency of n plates at total reflux, the reflux ratio should be between 2>t/3 and 3n/2. 

Read a recent article from the column Analytical Approach, published in Analytical Chemistry, or an article assigned by your instructor, and write an essay summarizing the nature of the problem and how it was solved. As a guide, refer back to Figure 1.3 for one model of the analytical approach. 

Historically azeotropic distillation processes were developed on an individual basis using experimentation to guide the design. The use of residue curve maps as a vehicle to explain the behavior of entire sequences of heterogeneous azeotropic distillation columns as weU as the individual columns that make up the sequence provides a unifying framework for design. This process can be appHed rapidly, and produces an exceUent starting point for detailed simulations and experiments. 

Column pipe coupling Guide spider Line Shalt Line Shalt coupling Column pipe... 

TLC can be used as an analytical technique, or as a guide to establishing conditions for column chromatography or as a preparative technique in its own right. 

However, with practical samples the way the (k ) values of the individual components for any given complex solute mixture are distributed is not predictable, and will vary very significantly from mixture to mixture, depending on the nature of the sample. Nevertheless, although the values for the theoretical peak capacity of a column given by equation (26) can be used as a reasonable practical guide for comparing different columns, the theoretical values that are obtained will always be in excess of the peak capacities that are actually realized in practice. 

By combining elements of the first column of the guide words with elements of columas 2 or 4 of the process parameters, process deviations may be found. For example, combining the first guide word, "No" from Table 3.3.4-1 with the first process parameter, Flow rate from Table >.3 4-4, the deviation No flow rate" is found. Other deviations may be created similarly... 

TABLE 4.11 Recommended Column Selection Guide for High-Performance Gel-Filtration Chromatography... 

While samples such as these have obviously been the focus for much GC X GC work in the past, the technology still remains to be demonstrated for many other sample types. It is likely that in the near future, as many more applications are studied, a general theory-or at least a guide to column selection for GC X GC applications-will reveal a logical approach to selection of phases that embodies the principles of orthogonality of separation. 

Column selection remains the most important factor in successful enantiomeric separations. The CSPs most likely to be effective in SFC are those that have been employed under normal phase conditions in LC. In fact, the tremendous body of knowledge that has been accumulated for LC can also guide column selection in SFC [66]. The likelihood of success with a particular CSP can generally be gauged after one or two injections [67]. If no evidence of separation is observed, another CSP should be investigated. 

For counter flow, gas flowing up a column through a falling shower film of liquid, Fair s correlation of collected data is to he used as a guide ... 

Adiabatic head, column (E), is a direct measure of the number of stages of centrifugal compression. In actual rating, the polytropic head must be used. As a guide, 8,000-10,000 ft of head are developed per stage of centrifugal compression, depending upon speed. 

Vehicles (external) Buffer rails, ramps Transporters (internal) Bollards, route demarcation, column base plinths, guide rails, Ilexible/automatic doors... 

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