Distance hydraulic lines

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. 

Petroleum oils have generally excellent properties for use in hydraulic systems but a major disadvantage is the possibility that ruptures in hydraulic lines will produce a very flammable mist of oil which can travel considerable distances. Once ignited, the atomized oil generates tremendous heat with disastrous consequences especially in the confined spaces of ships and submarines. The use of large amounts of... 

The vertical distance from the level of the surface at A in Fig. 10.2 down to the hydraulic gradient represents hf + V2/2g from A to any point in question. Hence the position of the gradient is independent of the position of the pipe. Thus it is not necessary to compute pressure heads at various points in the pipe to plot the gradient. Instead, values of hf+ V2/2g from A to various points can be laid off below the horizontal line through A, and this procedure is often more convenient. If the pipe is of uniform diameter, it is necessary to locate only a few points, and often only two are required. 

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. 

Figure 1 shows the test configuration having the form of two back-to-back cantilever beams with a central column. Load was applied at a distance of 1 m from the connection and measured by a 9 kN load cell connected in series with a manual hydraulic jack. Rotations of the column and connections were recorded using three electronic clinometers with a resolution of 0.02 mrad (linear to 1% over a i0° range). One clinometer was located along the centre-line of each beam and close to the end with the connection, while the third clinometer was located on the column above the joint. The two connection rotations were determined from the clinometer readings. 

The hydraulic cylinder contains the hydraulic oil necessary to enable the lifting action of the elevator. The total vertical travel distance of this particular elevator is 26 ft (7.92 m) and the cylinder volume is 3 gal/ft (11.4L/m). A total of 77 gal (291.5 L) of oil is encased by the cylinder when the elevator is in the uppermost position in the shaft. When fully lowered, the volume of oil in the cylinder is decreased to 42 gal (159 L). There is another 15 gal (58.6 L) of oil reserve over and above that required to raise the car to its maximum extension. There is an additional 4 gal (15.6 L) of oil contained on the lines connecting the power unit to the cylinder. Hence, the total oil contained in this system during full extension is equal to... 

These computed volumetric change rates led to an interesting observation that higher expansion of SrO polyhedra cause shrinkage in Ca-Ca interatomic distances. Shorter Ca-Ca interatomic distance thus lead to favorable to hydraulic activity of canent clinker compounds, which is in line with the experimental observations (Jost et al. 1977). 

Hydraulic transport through floating pipelines is the most common method of transport in reclamation operations. Part of the floating pipeline may be a sinker line to reduce hindrance to other shipping, to limit the pumping distance and to mitigate the effects of swell, waves and currents. 

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