Ground-beds horizontal

Figure 5.49 Typical horizontal anode design chart for impressed current ground beds. (From TEXACO Cathodic Protection - Design and application school, Texaco Houston Research Center, Training Manual. Reproduced by kind permission of Cheveron, USA)...

The above procedure can be used to determine the anode to earth resistance. Design charts can be constructed for vertical anodes and horizontal anode ground-beds for both impressed and galvanic anode systems. The development of design curves is discussed in Section 5.31.2. 

The following example shows how the design curve can be used to obtain the resistance of impressed current and galvanic anodes. Separate charts are constructed for impressed current ground-beds and horizontal ground-beds. With each chart the following design information is provided ... 

Fig. 9-3 Grounding resistance of anodes in a continuous coke bed with a covering of earth t = 1 m and a diameter d = 0.3 m for a specific soil resistivity of p = 10 Q m. Horizontal anodes from Eq. (24-23), see line 9 in Table 24-1 vertical anodes R ...

The constant, C, depends on the dimensions of the anode bed. It follows from line 4 of Table 24-1 for a horizontal ground in the half space... 

The wattage is directly proportional to the grounding resistance of the whole anode bed and therefore to the specific soil resistivity. Equation (9-5) gives the grounding resistance of the anode installation which either consists of n horizontal or vertical single anodes or of anodes with a horizontal continuous coke bed of total length I = ns. The total cost function is given by [1] ... 

The current requirement of the protected object basically determines the design of the anode bed. For example, for a pipeline requiring 10 A with horizontal anodes laid in soil with p = 45 H m, according to Fig. 9-14, eight anodes are necessary. The grounding resistance of one anode amounts to Rq = 14 H. From Fig. 9-8, the grounding resistance of the anode bed with an interference factor F= 1.34 for 8 anodes spaced at 5 m comes to R = 2.34 Q.. 

Coarsely ground material is placed in the body of the extractor which may be jacketed for control of the extraction temperature. The packing must be even or the solvent flows preferentially through a limited volume of the bed and leaching is inefficient. In large extractors, channeling is prevented or reduced by horizontal, perforated plates placed at intervals in the bed these redistribute the percolating liquid. 

The local site effects play an important role in the evaluation of seismic hazard. The proper evaluation of the local site effects will help in evaluating the amplification factors for different locations. This article deals with the evaluation of peak ground acceleration and response spectra based on the local site effects for the study area. The seismic hazard analysis was done based on a probabilistic logic tree approach and the peak horizontal acceleration (PHA) values at the bed rock level were evaluated. Different methods of site classification have been reviewed in the present work. The surface level peak ground acceleration (PGA) values were evaluatedfor the entire study area for four different site classes based on NEHRP site classification. The uniform hazard response spectrum (UHRS) has been developed for the city of Bangalore and the details are presented in this work. 

The design and performance of soil beds are described by Bohn and Bohn (1988). Basically, the system consists of a horizontal network of perforated pipe placed about 2 ft below ground level. The impure air is forced through the pipe network and upward through the soil before it enters the atmosphere. Contaminants in the feed air are adsorbed on particles of... 

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