Solid hydraulic lines

Figure 8. D ependence of the reactive force of a superheated-water jet on the initial pressure corresponding to the saturation line. Solid line - calculation for the hydraulic regime of outflow of a one-phase (non-boiling-up) liquid.

Figure 4.1. Hydraulic circuit. Head line (solid) and pressure line (dotted)...

Abbott, M. Ph.D. Thesis, University of London (1955). The Hydraulic Conveying of Solids in Pipe Lines. 

In a typical fixed-bed carbon column, the column is similar to a pressure filter and has an inlet distributor, an underdrain system, and a surface wash. During the adsorption cycle, the influent flow enters through the inlet distributor at the top of the column, and the groundwater flows downward through the bed and exits through the underdrain system. The unit hydraulic flow rate is usually 2 to 5 gpm/ft2. When the head loss becomes excessive due to the accumulated suspended solids, the column is taken off-line and backwashed. 

The experimental data (dots) are reproduced very well within the framework of the hydraulic permeation model (solid lines). For the basic case with zero gas pressure gradient between cathode and anode sides, APe = 0, the model (solid line) predicts uniform water distribution and constant membrane resistance at )p < 1 A cm and a steep increase in R/R beyond this point. These trends are in excellent agreement with experimental data (open circles) for Nafion 112 in Figure 6.15. A finife positive gas pressure gradient, APs = P/ - P/ > 0, improves the internal humidification of fhe membrane, leading to more uniform water distribution and significantly reduced dependence of membrane resistance on X. The latter trends are consistent with the predictions of fhe hydraulic permeation model. 

In the primary design, following that of the solid-gas impinging stream contactor used in earlier investigations on RTD and hydraulic resistance etc., the two nozzles are placed in the middle of the gas conduits (Point A, represented by the solid lines in Fig. 

Fig. 7a, b Average mass transfer coefficient as a function of a aquifer anisotropy ratio for several variances of the log-transformed hydraulic conductivity distribution b variance of the log-transformed hydraulic conductivity distribution where open circles represent numerically generated data and solid lines represent linear fits. All model parameter values are identical with those used in Fig. 6... 

The dispersion phenomenon in the two humid soils (Pembroke and Uniontown) was evaluated through the use of an Imhoff cone test and a permeameter. The Imhoff cone is commonly used by engineers to determine settleable solids (see Chapter 9). The results of clay dispersion obtained by the Imhoff cone test are expressed as a dispersion index (percent of total clays in the soil sample dispersed), which is correlated with relative saturated hydraulic conductivity. This is shown in Figure 11.5. It demonstrates that each of the soils, depending on its clay content (Pembroke 59% Uniontown 20%), exhibits unique saturated hydraulic conductivity behavior with respect to the dispersion index. Also, in each of the soils, various mechanisms (different line slopes) appear to control saturated hydraulic conductivity. 

FIGURE 6.33 Characteristic curves for water (solid line) and oil (dashed line). (Hydraulic Institute.)... 

Figure 1 Illustration of the development of increasingly complex flow systems as topography becomes more complex. Contours of hydraulic head are indicated by dashed lines and groundwater flow lines by solid arrows. Scale is arbitrary, but might correspond to 100 km in the horizontal direction. In (a), smooth topography produces a regional-scale flow system. In (b) and (c) increasing local topography creates a mixture of intermediate and local-scale flow systems superimposed on the regional one (Freeze and Witherspoon, 1967) (reproduced by permission of American Geophysical Union from Water Resour. Res. 1967, 3, 623-634).

The method for solids transported in slurry form is called hydraulic transportation. Today there are long distance rubber lined pipelines carrying a variety of minerals such as coal, limestone, rock phosphate, copper concentrate, nickel refinery tailings, iron ore concentrates and tailings in various parts of the world. The most important slurry pipelines in operation around the world are given in Table 4.2. 

Materials that are currently being transported over long distances by pipelines include coal, iron ore, limestone and copper concentrates. For hydraulic transportation over long distances to be economic, it is necessary that solids are reduced to an optimum size. To keep solids in suspension, a certain minimum velocity must be maintained. This velocity increases with the size of the particle. The increased velocity has a bearing on the wear life of the rubber lining. Wear in a slurry pipe line system increases with the cube of the velocity as well as increasing directly with the particle size. 

To transport 25 million tons of coal per year, only one meter diameter pipe is required. All the disadvantages of rail transportation are overcome including noise, dust, spillage and obstruction during traffic. Under favourable installation conditions, hydraulic transportation cost can be 50—60% less than the cost of rail transport. Slurry proportions for efficient transportation through rubber lined pipes are usually around 50% solids by weight. 

Figure 6.8 Hydraulic permeability of polysaccharide solutions. Adapted from [9]. Lines represent fits to the experimental data the dashed line was fit to heparin in NaCI (y = 3 X and the solid line was fit to chondroitin data (y = 2...

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