Column vacuum technology

Fig. 2.35. Schematic drawing of an absorption refrigeration plant based on information from Deutsche Babcock-Borsig AG, D-l 3500 Berlin and ALD Vacuum Technologies GmbH, D-63526 Erlensee, Germany. 1, Expulsion of NH3 from the water-NH3 solution 2, rectification column for NH3 3, NH3 condenser ...

These regions are characterized by the mean free path of the residual gas molecules and the type of gas streaming. The units for expressing the amount of pressure remaining in a vacuum system are based on the force of atmospheric air under standard conditions. This force amounts to 1.03 kg cm 2. Gas pressure is stated in terms of the height of a column of mercury supported by that pressure in a barometer. Atmospheric pressure of 1.03 kg cm 2 will support a column of mercury 760 mm. One torr is the equivalent of one millimeter or of 1/760 of atmospheric pressure. In modern vacuum technology the common unit is the bar. 1 mbar corresponds to 0.75 torr and this is equal to 102 pascal. 

Manometer, liquid (vacuum technology) A pressure-measuring device that uses a liquid column to measure the pressure difference in two volumes of gas. Often U-shaped... 

Extraction. Traditionally tea leaf is extracted with hot water either in columns or ketdes (88,89), although continuous Hquid soHd-type extractors have also been employed. To maintain a relatively low water-to-leaf ratio and achieve full extraction (35—45%), a countercurrent system is commonly used. The volatile aroma components are vacuum-stripped from the extract (90) or steam-distilled from the leaf before extraction (91). The diluted aroma (volatile constituents) is typically concentrated by distillation and retained for davoring products. Technology has been developed to employ enzymatic treatments prior to extraction to increase the yield of soHds (92) and induce cold water solubiUty (93,94). 

Column, gas chromatograph FlP-5, 5% phenyl-methyl capillary column, 0.25-mm i.d. X 12-m length, 0.33-qm film thickness (Agilent Technologies) or equivalent Evaporator, rotary vacuum, water-bath set at 60 and 40 °C Processors ... 

Two-phase extraction uses a vacuum source to remove contaminated groundwater and soil vapor from the subsurface. The vacuum is applied to an extraction tube within a water well to increase groundwater removal rates and to volatilize and extract VOCs. According to the vendor, vacuum lift of water is not a limiting factor in the application of the technology. Since a mixed vapor/liquid column is extracted from the weU, the two-phase extraction technology allows a single piece of equipment (a vacuum source) to remove contaminants in both the liquid and vapor phases. 

Products/technologies These include Visiprep solid phase extraction vacuum manifolds to manipulate combinatorial chemistry reaction mixtures a rare chemicals library of over 60,000 products CombiKits to create a customized kit of preweighed building blocks SUPELCOSIL ABZ+ HPLC columns and a chemical directory on CD-ROM. 

When I started at IBM in 1967,1 was convinced that technology innovation had reached its pinnacle. What could be more state-of-the-art than the vacuum tube How could you ever improve on the 80-column punch card as the user-friendly input device What could be more advanced than storing five megabytes of data by stacking 50 24-inch discs on top of each other And what could possibly replace the thousands of tiny ceramic ferrite cores that were strung togethCT to form a computer s memory ... 

---