Purge time

To keep the sweeping-out or purge time as short as possible, the solenoid valve should be close to the burner, and it should close quickly. In addition, the line between the solenoid valve and the burner should not drain into the furnace. As in the previous incident, the furnace had been lit incorrectly for many years before an explosion occurred. 

Equation 5.56 is known as the purging time equation for a system of... 

FIGURE 14.5. FTIR spectra for CO adsorption on Au72Pt28/Si02 catalyst calcined at 400°C under two different sample preparation conditions (A and B). N2-purging times 0 min (the spectrum was corrected by subtracting the gas-phase CO spectrum) (A), and 1 min (top) and 52 min (bottom (the gas-phase CO is absent)) (B). 

The parts produced were in specification and did not have the splay defect. When the press was switched between different colored resins, the purge time was very short and typically required less than 20 parts. The higher compression ratio and compression rate screw combined with channels that had large radii provided a constant plastication rate and no detectable degradation of the resin. 

Grob, C. and Wortberg, J., Optimizing Purging Time at Product Change in Blown Film Extrusion by Selective Modification of Process Parameters, SPE ANTEC Tech. Papers, 50, 261 (2004)... 

It is important to perform a data capture operation for electronic data as soon as possible to maximize the quantity and quality of such information. For example, one investigator had to download the data within the preset file purge time of eight hours. The programmer was on vacation and there was no documentation available on the program. Even when computer specialists are available, this may be a difficult task because computer specialists do not frequently encounter the questions asked by investigators, f f there is a of loss of electric power, information may be accessible for a limited period due to battery backup for volatile memory. (Email should also be considered as electronic evidence.)... 

Table I contains a list of some of the compounds that have been submitted to this type of analysis. The recovery data is intended to be illustrative only since recoveries depend strongly on several important method variables. Recoveries are expressed as a percentage of the amount added to organic free water. The purge time was 11-15 minutes with helium or nitrogen, the purge rate was 20 ml/minute at ambient temperature, and the trap was Tenax followed by Silica Gel. Data from the 5 ml sample was obtained with a custom made purging device and either flame ionization, microcoulo-metric, or electrolytic conductivity GC detectors. Data from the 25 ml sample was obtained with a Tekmar commercial liquid sample concentrator and a mass spectrometer GC detector using CRMS.

Figures 15.4 and 15.5 illustrate a parallel flow arrangement which has the advantage of requiring shorter purge times when changing gas composition but is somewhat more wasteful of the mixed gases. The symbols shown in Fig. 15.4 have the same meaning as used in Fig. 15.1.

Fig. 4. The amounts of thermally desorbed products from cis-2-butene adsorption on a-Fe203 versus purging time at -78°C. Data for total products and for total desorption include the same molecules as those in Fig. 3. From ref.6, reprinted with permission from Academic Press.

Two different techniques were used to remove volatile compounds from the coffee. The first was vacuum distillation in a rotary evaporator. A 20 mL aliquot of coffee was placed in a round bottom flask and then it was attached to a Roto-vap and held in a water bath at 60 C during rotation with a vacuum applied from a water aspirator. When 15 mL had been distilled into the collection flask, it was removed and 20 mL distilled water was added to the 5 mL of retentate and the process of rotary evaporation repeated to yield a total of four distillates. Gas chromatographic analyses were performed using purge and trap as described above, with a purge time of 15 minutes. 

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