Surface pumping systems

Rather moderate flow rates and pressures are required to operate the positive displacement motor. Thus, most surface pump systems can be used to operate these downhole motors. 

The principle of operation of the hydraulic reciprocating pump is similar to the beam pump, with a piston-like sub-surface pump action. The energy to drive the pump, however, is delivered through a hydraulic medium, the power fluid, commonly oil or water. The power fluid drives a downhole hydraulic motor which in turn drives the pump. A separate surface pump delivers the hydraulic power. The power fluid system can be of the closed loop or of the open type. In the latter case, the power fluids are mixed with the produced fluid stream. The performance of the hydraulic pump is primarily monitored by measuring the discharge pressures of both surface and sub-surface pumps. 

The surface mud system is designed to restore the mud to the required properties before it is pumped downhole. Most of the equipment is used for solids removal only a small part of the surface mud system is designed to treat chemical contamination of the mud. There are three basic means of removing drilled solids from the mud dilution-discard, chemical treatment, and mechanical removal. 

This is a closed steam surface condenser system with condensate being pumped out to retreatment facilities. From the conditions noted on the diagram,... 

In actual experiments we do not usually observe directly the desorbed amount, but rather the derived read-out quantities, as is the time dependence of the pressure in most cases. In a closed system, this pressure is obviously a monotonously increasing function of time. In a flow or pumped system, the pressure-time dependence can exert a maximum, which is a function of the maximum desorption rate, but need not necessarily occur at the same time due to the effect of the pumping speed S. If there are particles on the surface which require different activation energies Ed for their desorption, several maxima (peaks) appear on the time curve of the recorded quantity reflecting the desorption process (total or partial pressure, weight loss). Thereby, the so-called desorption spectrum arises. It is naturally advantageous to evaluate the required kinetic parameters of the desorption processes from the primarily registered read-out curves, particularly from their maxima which are the best defined points. 

The storage is linked to a district cooling system that serves the inner city of Stockholm in Brunkebergs Torg (Figure 90) with natural cold from a lake (Vartan). The surface water is produced from a depth of 35 m and has a temperature ranging from +4 to +6 °C. A heat pump system can lower the supply temperature to +3 °C if required. 

The trench method is applicable only when the water table is relatively shallow, less than 10 to 15 ft below the ground surface. For a deeper water table, the cost of the trench method becomes more expensive than other methods such as pump systems. Another limitation of the trench method is the soil structure. The soil above the water table has to be firm and well aggregated to allow for the trench to be self-supporting. Otherwise, embankment enforcement or screening would be needed. A third limitation is that continuous pumping and skimming is required to maintain a flow gradient towards the trench. Otherwise, the free product will move back and reenter the soil. 

For the pumping system, seawater was pumped up from 9 m and collected in the appropriate bottles on the raft and returned to the shore clean laboratory for preservation and/or analysis. For the other four sampling devices, the sampler was lowered to 9 m, allowed to equilibrate for 10 min, closed by triggering mechanism activated by the Teflon messenger, raised to the surface, transferred into the container, transported back by boat and trucked back... 

At sites where the fluid level (water or LNAPL) is below the suction-lift depth, the use of a down-hole pumping unit is necessary. When a single-pump system is used, the water and/or LNAPL is delivered to the surface for separation or treatment, as shown in Figure 7.12. Several types of single-pump systems are in common usage. 

Considering the spatial geometry of cerebral capillaries and capillary blood flow, a number of dynamic models of the blood-brain barrier have been developed, in which endothelial cells are cultured inside a permeable tube, the outer surface of which is coated with astrocytes. Supply of the cells with nutrients and artificial blood flow are maintained by using a peristaltic pump system [112, 113]. 

The vacuum system must be able to attain the required pressures reliably despite these high gas loads. In the example shown, the system is evacuated with a combination of a backing and Roots pump. A diffusion pump along with a cold surface forms the high vacuum pump system. The cold surfaces pump a large portion of the vapor and volatile substances emitted by the plastic parts while the diffusion pump basically removes the non-condensable gases as well as the noble gas required for the sputter process. 

Advantages of microbial barriers over conventional pump-and-treat systems are that barriers can eliminate the need for additional treatment, and they do not disrupt the namral flow of groundwater. Furthermore, if contaminants can be volatilized or biodegraded throughout the impacted portion of an aquifer, there is no need for surface treatment systems, discharges,... 

Some of the modern surface analysis methods have been used to study the surface chemistry of both plasma etched surfaces and plasma polymerized thin films. Much of this work has involved exposure of these surfaces to air as the samples are transferred from the plasma system to the surface analysis system. However, in a few cases surface analysis has been performed in the plasma system after the plasma gas has been pumped away. This work will be discussed in more detail later in this chapter. 

Ceramic materials, including sapphire, have been used extensively in HPLC pumps for more than 20 years as pistons and check valve components. These materials have also been used to construct heads because of their good chemical stability. The use of ceramics is limited, however, because of high cost and brittleness. Although many systems have one material as the primary construction material, the wetted surfaces of a pumping system can contain several other materials. Therefore, for material-sensitive applications, all the materials in the HPLC eluent flow path should be considered. Materials that may be encountered are polymeric materials for pump seals such as fluoropolymers, polypropylene, and Teflon sapphire pump pistons and check valve seats ruby check valve balls Kalrez, KelF, or ceramic washers and spacers polymer-based transducer components and in older systems connections and joints made with silver solder. 

The sample preparation chamber on a surface analysis system (AES, XPS) is fitted with an ion gun for depth profiling (see diagram). The gun can be differentially pumped to maintain the required pressure difference between the ion source and the preparation chamber, which is initially fitted with a TMP with 5eff = 50 L s 1. 

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