Pump-out lines

A sump and pump had been provided for the removal of water. But either the pump-out line had become blocked or pumping had not been canied out regularly [7]. 

Alternately, a low TDS result for lean amine shows that steam or condensate is entering the amine system. Verify that the condensate make-up valve is closed. Then block in any cross connections between the amine system and sour water pump-out lines, etc. Next, block in the reclaimer vapor... 

Following some mtxiifications to a pump, an operator pressed the stop button on the control panel and saw that the pump running light went out hence closed a remotely operated valve in the pump delivery line. Several houi s later the high-temperature alarm on the pump sounded soon afterward there was an explosion in the pump... 

After a landfill site has been chosen and a basin has been excavated, the basin is lined with one or more layers of water-retaining material (liners) that form a leachate bathtub. The contained leachate is pumped out through a network of pipes and collector layers. Liners may be constructed of synthetic polymer sheets or of clay. U.S. EPA s MTG3A7 relies on a composite liner that utilizes the advantages obtained from combining both liner systems. 

A chemist s vacuum line will often be pumped out several times within any working day and therefore the time taken to reach a useful vacuum should be as short as possible. The time taken by a system to reach the described vacuum depends upon the volume of the system, its internal surface area, the materials used for its construction, its cleanness, the speed of the pumps and the aerodynamic conductance of the system. 

Fig. 4.40 Procedures used in measuring the dipole moment of adatoms by an FIM-FEM combination experiment, (a) A clean W surface is prepared by low temperature field evaporation and characterized by the FIM image. (b) The (110) plane is lined up with a Faraday cap using an external gimbal, the image gas is pumped out and the polarity of the tip is changed. A FN plot is then taken, (c) Adatoms are deposited on the (110) surface and their number found by the field ion image, in this case 9 adatoms. (d) A FN plot is taken again from the same surface area but now with the presence of 9 adatoms on the surface, (e) Two sets of data collected from two different (110) planes are shown (circles are for clean W (110), and squares are with 10 adatoms). The solid lines are for W adatoms and the broken lines are for Ta adatoms.

The solution was contained in a cylindrical Pyrex or silica optical cell, 2.5 cm. in diameter and 2 cm. optical depth, fitted with a side arm of diameter about 1 cm. for connection to the vacuum line (see Fig. 10). Both phosphorescence and delayed fluorescence in fluid solution at room temperature are quenched by exceedingly low concentrations of molecular oxygen, and efficient deaeration is of the utmost importance. The following procedure was found to be satisfactory. The cell was first cooled in an acetone/C02 bath and pumped out. It was then isolated from the pump, refluxed to remove dissolved gas, cooled again in the... 

Vapor pressures, which are readily determined on a vacuum line, provide a convenient and sensitive means of identifying a volatile compound and/or checking its purity. The sample is condensed at liquid nitrogen temperature and all of the residual gases are pumped out of the system. If the compound has been exposed to the atmosphere immediately prior to the measurement, it should be degassed by several freeze-pump-thaw cycles. 

The sequence of operations (assuming the initial solid is not air sensitive) would be to load the sample tube with a weighed amount of reactive compound and the stirrer, to attach this tube to the tensimeter, and to pump out the air in the tensimeter. The sample tube is cooled to liquid nitrogen temperature and solvent is then condensed into the sample tube from a storage container on the vacuum line. The main valve on the tensimeter is then closed and the sample container allowed to warm so the solid may dissolve, perhaps with the aid of the stirrer. A constant temperature slush bath is next placed around the sample tube as illustrated in Fig. 9.5 and an initial pressure measurement is taken on the manometer. Next, the first alloquot of the reactive gas is transferred from a storage bulb elsewhere on the vacuum system into the calibrated bulb using the techniques outlined in Section 5.3.G (the bubbler manometer shown in Fig. 9.5 is used for the pressure determination required for this process). This gas is con-... 

However, the overflow line also served as a vent line. In short, during one of the times the tank was in the process of being pumped out, it partially collapsed. The water in the bucket overflow line sealed out the air and the resulting partial vacuum was so severe that the tank was completely destroyed. 

The catch to the vacuum method is that you must have a controlled boil without which the material and/or solvent are liable to be sprayed all over your vacuum system. Although a solvent can easily be pumped out of a vacuum system, it can cause serious problems if it remains in contact with stopcock grease, O-rings, or mechanical and/or diffusion pump oils. Any particulate material deposited within a vacuum line can only be removed from the vacuum line by disassembly and cleaning. With a glass vacuum system, such a cleaning may be difficult or impossible. 

Approximately 0.5-1.0 ml. of NTO is run into a sample tube, and the tube is quickly capped with a 12/30 outer joint glass cap. Next, the tube is immersed in LN2 to freeze the NTO. The cap is removed, and the taper joint is attached to a vacuum line as quickly as possible. Still frozen, the tube is pumped out and sealed off with a torch at the junction between the NMR tube proper and the taper joint Samples so prepared may be stored indefinitely without deterioration or accumulation of moisture. 

Now, to derive the equalization required, refer to Figure 3.10. The curve represents inflow to an equalization basin. The unit on the ordinate is mVh and that on the abscissa is hours. Thus, any area of the curve is volume. The line identified as average represents the mean rate of pumping of the inflow out of the equalization basin. The area between the inflow curve and this average (or mean) labeled B is the area representing the volume not withdrawn by pumping out at the mean rate ... 

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