Annular space, concentric

Suspend the bomb by a wire or a metal rod through F. Fill with water the annular space between the pillar F and the hole in the top of H. Now heat the base of A with a pointed flame, e.., from a blowpipe pointing upwards. The time required for heating in this way is usually about i minute, but an ordinary Bunsen flame, used without concentration on the bottom of A, may require about 4 minutes. The... 

Consider a flow of argon of 0.5 L/min through an annular space of 4 x 10" cm between two concentric capillary tubes at normal ambient temperatures. If the density of argon is taken to be 1.2 X 10 gem then,... 

Figure 19.7 shows a typical construction of a concentric-tube nebulizer. The sample (analyte) solution is placed in the innermost of two concentric capillary tubes and a flow of argon is forced down the annular space between the two tubes. As it emerges, the fast-flowing gas stream causes a partial vacuum at the end of the inner tube (Figure 19.4), and the sample solution lifts out (Figure 19.5). Where the emerging solution meets the fast-flowing gas, it is broken into an aerosol (Figure 19.7), which is swept along with the gas and eventually reaches the plasma flame. Uptake of sample solution is commonly a few milliliters per minute.

In an oil cooler 216 kg/h of hot oil enters a thin metal pipe of diameter 25 mm. An equal mass flow of cooling water passes through the annular space between the pipe and a larger concentric pipe with the oil and water moving in opposite directions. The oil enters at 420 K and is to be cooled to 320 K. If the water enters at 290 K, what length of pipe will be required Take coefficients of 1.6 kW/m2 K on the oil side and 3.6 kW/tn2 K on the water side and 2.0 kJ/kg K for the specific heat of the oil. 

Longitudinal fins can also be used, but their application is restricted to small heat exchangers in the form of a concentric pipe heat exchanger, similar to the schematic in Figure 15.5a. In this arrangement, the inner tube would be the extended surface tube with the fins in the annular space to enhance the heat transfer. Longitudinal fins can increase the surface area by a factor of 14 to 20 relative to plain tubes. 

The tube-in-tube or multitube-in-tube heat exchangers are useful in small Linde lique-fiers or in the final Joule-Thomson stage of any liquefier. The performance of Linde-type exchangers is easy to calculate, and their realization is simple. In the examples shown in Fig. 5.12 (a)-(c), the tubes are concentric and the outer wall contributes appreciably to the pressure drop in the outer stream without contributing to the heat transfer. Usually, the smaller inner tube is used for the high-pressure stream and the low-pressure stream flows through the outer annular space. The tubes in Fig. 5.12 (d) and (e) are solder bonded while that in (f) is flattened and twisted before insertion into an outer tube. 

Frasch (1) A process for extracting sulfur from underground deposits, developed by H. Frasch between 1890 and 1902 at Sulfur Mine, LA. Three concentric pipes are inserted into a hole drilled into the deposit. The outermost pipe carries water superheated to 140 to 165°C, which melts the sulfur hot air is forced down the central pipe, which forces the molten sulfur up through the intermediate annular space. Only a small proportion of sulfur deposits have the appropriate geology for extraction in this way. Because of this invention, sulfur came to be exported from America to Europe, instead of from Sicily to America. In 1991 the process was operated in the United States, Mexico, Poland, and Iraq. 

Large concentrations of unprotected cable or conduit penetrations can result in significant entry of blast pressures. Through the use of proprietary devices, the annular space around cable or conduit can be completely sealed, Alternatively, custom designed closure plates may also be used. 

Bomb Igniter, AN-M9, shown in Fig 5-13, consists of two concentric steel tubes joined at both ends to form an annular space which is filled with 1.6-lb of WP for land bombing or Na for water bombing. Outside diam is 1.25-inches, inside diam 0.88-in and overall length 38.34-in. The inner tube, which is ca 1.25-in shorter than the outer tube, contains a small coil spring for snubbing inserted bomb burster Ml3 (Ref 51a, p5-21)... 

The IL airlift reactor shown in Figure 7.11a is a modification of the bubble column equipped with a draft tube (a concentric cylindrical partition) that divides the column into two sections of roughly equal sectional areas. These are the central riser for upward fluid flow and the annular downcomer for downward fluid flow. Gas is sparged at the bottom of the draft tube. In another type of IL airlift, the gas is sparged at the bottom of the annular space, which acts as the riser, while the central draft tube serves as the downcomer. 

The most important deposits of sulphur in the world arc those of Louisiana and Texas, U.S.A., where //. Franck s method of extraction is followed.2 This obviates the formation of sulphur dioxide and at the same time yields a product of such a degree of purity (in some wells as high as 99-9 per cent.) as to be suitable in most cases for direct use. A boring is made in the earth down to the sulphur stratum so that a continuous pipe can pass thence to the surface the pipe consists of throe concentric tubes (see lig. 1). Superheated water, c.g. at 150" is forced down the annular spaces A, A, between the outer tubes, in order to melt the sulphur in the neighbourhood of the cud of the boring. A blast of heated air down the inmost tube, II, then causes the molten sulphur to be carried up between the two inner tubes to the surface, where it is collected.3... 

The problem to be solved in this paragraph is to determine the rate of spread of the chromatogram under the following conditions. The gas and liquid phases flow in the annular space between two coaxial cylinders of radii ro and r2, the interface being a cylinder with the same axis and radius rx (0 r0 < r < r2). Both phases may be in motion with linear velocity a function of radial distance from the axis, r, and the solute diffuses in both phases with a diffusion coefficient which may also be a function of r. At equilibrium the concentration of solute in the liquid, c2, is a constant multiple of that in the gas, ci(c2 = acj) and at any instant the rate of transfer across the interface is proportional to the distance from equilibrium there, i.e. the value of (c2 - aci). The dispersion of the solute is due to three processes (i) the combined effect of diffusion and convection in the gas phase, (ii) the finite rate of transfer at the interface, (iii) the combined effect of diffusion and convection in the liquid phase. In what follows the equations will often be in sets of five, labelled (a),..., (e) the differential equations expression the three processes (i), (ii) (iii) above are always (b), (c) and (d), respectively equations (a) and (e) represent the condition that there is no flow over the boundaries at r = r0 and r = r2. 

Axial Pressure Flow between Concentric Cylinders Solve the problem of flow in the horizontal concentric annular space formed by two long cylinders of length L and radii Rt and Ra, caused by an entrance pressure Pp, which is higher than the exit (atmospheric) pressure. Consider the limit as (Rp — R,) / (Rp + Rt) approaches zero. 

Helical Flow between Concentric Cylinders Consider the helical flow in an annular space created by a constant pressure drop (Pp — P ) and the rotation of the inner cylinder with an angular velocity il(s ). 

The Haldor Topsoe Convection Reformer (HTCR) has been developed for the production of hydrogen from hydrocarbons without steam generation. The elementary unit of the reformer consists of two concentric tubes (Fig. 1.21). The annular space... 

Continuous chromatography in the packed annular space between the walls of two concentric cylinders can be done by rotating the assembly about its longitudinal axis (1, 2, 3). Rotation transforms the temporal separation that would be obtained under fixed, pulsed operation into a spatial separation that permits continuous operation. It has recently been shown that continuous reaction chromatography can be done in similar apparatus (4, Jj). This not only provides a means of carrying out chemical reaction and separation simultaneously in one unit, but for A B + C the product separation suppresses the rate of the back reaction and provides a means of enhancing the reaction yield. Yield enhancement in pulsed column chromatography has been demonstrated (6, 8). Yields of... 

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