Metallic tubes

In America, the sulphur deposits (mostly in Louisiana and Texas) are dome-shaped layers about 30 cm thick, between limestone above and anhydrite below. From these, the sulphur is extracted by the Frasch process. A metal tube, about 15 cm diameter and containing two concentric inner tubes (Figure 10.1) is sunk into the top of the deposit. Water, superheated to 450 K, is forced... 

Both microwave and millimetre wave radiation can be channelled in any direction by a waveguide made from metal tubing of rectangular cross-section, the dimensions depending on the frequency range. The absorption cell is also made from waveguide tubing. 

Although the CFCs and HCFCs are not as stable as the PFCs, they still can be rather stable compounds (3,11)- Dichlorodifluoromethane, CCI2F2, is stable at 500°C in quartz CCl F and CHCIF2 begin to decompose at 450 and 290°C, respectively (7). The pyrolysis of CHCIF2 at 650—700°C in metal tubes is the basis of a commercial synthesis of tetrafluoroethylene ... 

In one extractor (FMC Inc.), the fmit is located between two cups having sharp-edged metal tubes at their base. The upper cup descends and the many fingers on each cup mesh to express the juice as the tubes cut holes in the top and bottom of the fmit. On further compression, the rag, seeds, and juice sacs are compressed into the bottom tube between the two plugs of peel. A piston moves up inside the bottom tube forcing the juice through perforations in the tube wall. A simultaneous water spray washes the peel oil expressed during extraction away from the peel as an oil—water emulsion the peel oil is recovered separately from the emulsion. 

Drilhng. Glass is dtiUed with carbide or bonded-diamond dtiUs under a suitable coolant such as water or kerosene. Other drilling processes include a metal tube rotating about its axis (core drilling), an ultrasonic tool in combination with an abrasive slurry, or an electron beam. Tolerances less than 0.1 mm are readily obtained with diamond-core drilling and, if required, holes smaller than 25 )J.m-dia can be made with the electron-beam method. 

In nonmetaUic vessels, the second plate of the capacitor is missing and must be suppHed. A stiUweU probe, one with a concentric metal tube, is utilized. The concentric tube suppHes the second plate. StiUweU probes have numerous other uses. In appHcations of nonconductive media, a stiUweU probe is more sensitive and suppHes a greater amount of capacitance because the ground reference is so close to the probe. Further, if a tank waU offers a ground reference that is a varyiag distance to the probe, eg, a horizontal cylinder, the stiUweU offers a much more consistent (linear) ground reference. 

The fifth component is the stmcture, a material selected for weak absorption for neutrons, and having adequate strength and resistance to corrosion. In thermal reactors, uranium oxide pellets are held and supported by metal tubes, called the cladding. The cladding is composed of zirconium, in the form of an alloy called Zircaloy. Some early reactors used aluminum fast reactors use stainless steel. Additional hardware is required to hold the bundles of fuel rods within a fuel assembly and to support the assembhes that are inserted and removed from the reactor core. Stainless steel is commonly used for such hardware. If the reactor is operated at high temperature and pressure, a thick-walled steel reactor vessel is needed. 

It is important that the rate of circulation within the waterwaH tubes be great enough to carry heat away from the metal tube walls fast enough to prevent the walls from overheating. Because the circulation is dependent on the difference ia density between the cooler water found ia the downcomers and the hotter water and steam located ia the waterwaHs, the rate of circulation iacreases as this differential pressure iacreases. Thus, the rate of heat transfer from the combustion 2one to waterwaHs, the height of the boiler, and its operating pressure all combine to determine the rate of circulation. 

FIG. 6-12 Correction factor for PoiseiiiUe s equation at low pressures. Curve A experimental curve for glass capillaries and smooth metal tubes. (From Brown, et al, J. Appl. Phys., 17, 802 [1.946].) Curve B experimental curve for iron pipe (From Biggie, Couiiesy of E. I. du Pont de Nemours [Pg.641]

Bimetallic Tubes When corrosive requirements or temperature conditions do not permit the use of a single alloy for the tubes, bimetalhc (or duplex) tubes may be used. These can be made from almost anv possible combination of metals. Tube sizes and gauges can be varied. For thin gauges the wall thickness is generally divided equally between the two components. In heavier gauges the more expensive component may comprise from a fifth to a third of the total thickness. 

Indirect. steam-tube dryer This is a bare metal cylinder provided with one or more rows of metal tubes installed longitudinally in the shell. It is suitable for operation up to available steam temperatures or in processes requiring water cooling of the tubes. 

Adiabatic compression test. High pressure is applied r idly to a liquid in a U-shaped metal tube. Bubbles of hot compressea gas are... 

A polypropylene pipe of inside diameter 10 mm and outside diameter 12 mm is pushed on to a rigid metal tube of outside diameter 10.16 mm. If the polypropylene pipe is in contact with the metal tube over a distance of 15 mm, calculate the axi force necessary to separate the two pipes (a) immediately after they are connected (b) 1 year after connection. The coefficient of friction between the two materials is 0.3 and the creep data in Fig. 2.5 may be used. 

Air heaters in industrial environments require corrosion-protective finishes that are capable of protecting the coil and case from damage by condensation, acid vapors, or aggressive chemicals, in the air or the primary medium. If air washers are used with coils placed after them, copper or other noncorroding metal tubes should be used. 

As well as measurement errors due to the pressure measurement instrument itself, other errors related to pressure measurements must be considered. In ventilation applications a frequently measured quantity is the duct static pressure. This is determined by drilling in the duct a hole or holes in which a metal tube is secured. The rubber tube of the manometer is attached to the metal tube, and the pressure difference between the hole and the environment or some other pressure is measured. 

It will be intriguing to theoretically examine the possibility of superconductivity in CNT prior to the actual experimental assessment. A preliminary estimation of superconducting transition temperature (T ) for metallic CNT has been performed considering the electron-phonon coupling within the framework of the BCS theory [31]. It is important to note that there can generally exist the competition between Peierls- and superconductivity (BCS-type) transitions in lowdimensional materials. However, as has been described in Sec. 2.3, the Peierls transition can probably be suppressed in the metallic tube (a, a) due to small Fermi integrals as a whole [20]. 

A hot-iuater funnel is shown in Fig. 42. It consists of a jacketed metal funnel, udth a projecting metal tube. The vessel is partly filled with water which is boiled by placing a small buiner under the end of the tul )e. The glass funnel is placed within the metal-jacket. By keeping the liquid hot, ciystallisation in the filter is thus prevented. 

Metall-oxyd, n. metallic oxide, -oxydhydrat, n. metal (lie) hydroxide, -papier, n. metal (lie) paper, -poliermittel, n. metal polish, -probe, /, test for metal, assay, -putzmittel, n. metal polish, -rohr, n., -rbhre, /. metal tube oi-pipe, -rohrehett, n. (small) metal tube or pipe, -riickstand, m. metallic residue, -sa-fran, m. crocus of antimony, -salz, n. metallic salt. 

Metall-salzUSsung, /. metallic-salt solution, -saure, /. metallic acid (as HMn04). -schlacke,/. metal slag, -schlauch, m. (flexible) metallic tube, metallic hose, -schliff,... 

Finally, the enriched uranium of converted back into UO,. The UO, is pressed into small fuel pellets and packaged in a metal tube (made of a zirconium alloy) for use in a nuclear reactor. 

This calculation neglects the temperature drop across the metal tube wall and considers the entire tube to be at the temperature of the outside surface of the wall, k. Kem for the same equation suggests using the caloric temperature for k and h. 

Resistance of fouling and metal tube wall required for balanced operation of reboiler ... 

Flexible tubes Metallic tubes complying with BS 669, Part 2 or BS 6501 shall be used other than with small portable appliances or with domestic-type appliances, in which case they shall comply with BS 669 Part 1. A manual valve shall be fitted on the inlet side in close proximity to the tube. The pipework shall be adequately supported such that the tube does not support the weight of the attached pipework. Tubes shall be installed so that they are neither twisted nor subjected to torsional strain, have flexing in one plane only, and are not subject to sharp bends near end fittings. 

A recent development in heat recovery has been the heat tube. This is a sealed metal tube which has been evacuated of air and contains a small quantity of liquid which, for boiler applications, could be water. When heat from the flue gases is applied to one end of the heat pipes the water in the tube boils, turning to steam and absorbing the latent heat of evaporation. The steam travels to the opposite end of the tube which is surrounded by water, where it gives up its latent heat, condenses and returns to the heated end of the tube. Batteries of these tubes can be arranged to form units, usually as a water jacket around a section of a flue. 

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