Pumping Systems Lines

Diffusion Pump System. After the pump line and trap have been shut off, a large valve is opened slowly enough that the mass flow of gas from the chamber through the valve into the od-diffusion pump system does not dismpt the top jet of the diffusion pump (DP) (Fig. 4). When the Hquid nitrogen is replenished after the trap has been operated for some time, release of previously trapped gas must be avoided. The so-caded ionization-gauge response pips at the start of the Hquid-nitrogen replenishment are an indication of trap ineffectiveness. 

Where Water Hammer Occurs. Water hammer can occur in any water supply line, hot or cold. Its effects can be even more pronounced in heterogeneous or biphase systems. Biphase systems carry water in two states, as a liquid and as a gas. Such a condition exists in a steam system where condensate coexists with live or flash steam in heat exchangers, tracer lines, steam mains, condensate return lines and, in some cases, pump discharge lines. 

Thermal shock In biphase systems, steam bubbles may become trapped in pools of condensate in a flooded main, branch, or tracer line, as well as in heat exchanger tubing and pumped condensate lines. Since condensate temperature is almost always below saturation, the steam will immediately collapse. 

Note when used for pump system balance, this Zhf must be used as a negative number ( — 0.1863) because it is a pressure loss associated with the fluid flowing. For pipe line sizing, the pressure head on the tank of 5 psig and any elevation difference between tank outlet nozzle and pump suction centerline do not enter into the calculations. 

Scale Inhibitor. About 3 to 5 gal (20 to 30% active) of scale inhibitor per day should be sufficient for scale inhibition. The treatment can be reduced to 1 to 3 gal per day once the scale formation is under control. The chemical can be introduced to the system by injecting it into the pump suction line. 

The inside of the reservoir generally will have baffles to prevent excessive sloshing of the fluid and to put a partition between the fluid return line and the pump suction or inlet line. The partition forces the returning fluid to travel farther around the tank before being drawn back into the active system through the pump inlet line. This aids in settling the contamination and separating air entrained in the fluid. 

Impingement separators, 246, 257 Chevron style, 248, 255 Efficiencies, 246 Knitted wire mesh, 246 York-vane efficiencies, 248 Inertial centrifugal separators, 266, 268 Kinetic energy, pump system, 187 Lamella plate classifiers, 239 Line sizing work sheet, 107... 

Chlorine addition may be a prerequisite to sanitize the RO RW supply line and oxidize any organics (followed by dechlorination using sodium bisulfite after the MM filtration stage). Where chlorine is required, it is usual to provide a 20- to 25-minute contact period by means of a temporary storage tank. This is followed by a repressurization pump system. 

The chip micro reactor ([R 6]) was only one part of a complex serial-screening apparatus [20]. This automated system consists of an autosampler (CTC-HTS Pal system) which introduces the reactant solutions in the chip via capillaries. A pumping system (p-HPLC-CEC System) serves for fluid motion by hydro dynamic-driven flow. A dilution system [Jasco PU-15(5)] is used for slug dilution on-chip. The detection system was a Jasco UV-1575 and analysis was carried out by LC/MS (Agilent 1100 series capLC-Waters Micromass ZQ). All components were on-line and self-configured. 

The important heads to consider in a pumping system are the suction, discharge, total and available net positive suction heads. The following definitions are given in reference to the typical pumping system shown in Figure 4.1 where the arbitrarily chosen base line is the centre-line of the pump. 

Turn on the on-line vacuum degasser and the seal wash pump system (if available). 

A portable electronic data acquisition system was transported to the plant site and connected to the extruder panel. All available instrument outputs from the panel were connected in parallel with the acquisition system. Data collected included barrel zone temperatures, screw speed, motor current, pressure at the entry to the pump, transfer line temperature, and gear pump temperature. Process data were collected at a frequency of once every five seconds. 

The UHV pumping systems are mounted similarly in an open glove box frame and connected with the roughing pumps by vacuum lines containing absolute filters to keep back potential radioactive contaminants. 

The pumping system is the most important part of the vacuum line, it is certainly the most expensive, and it should therefore be chosen with care. Because the pumping system on a chemist s vacuum line must be robust and capable of removing large quantities of gases, often in repeated cycles, sorption pumps, getter ion pumps, and sublimation pumps are generally unsuitable and are therefore not discussed in this book. 

The purpose of the cold traps (see Fig. 2.1.) is two-fold (1) to trap volatile materials from the line on their way to the pumps and thus to protect the pumping system and (2) to trap the vapour and any pumping fluid before it can enter the line by back-diffusion. 

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