Roof ring

The roof, in the form of a dome, is either comprised of refractory brick held in place by a water-cooled steel roof ring, or it may be composed of water-cooled panels. Sometimes water-cooled rings or glands are placed on the roof around the electrodes to maintain the refractory. On high power furnaces refractory is used around the electrodes to minimize the possibiUty of electrical short circuits. 

For tank internal pressures that do not exceed the weight of the roof plates, most tanks have conical roofs because these are the simplest and most cost-effective. When the pressure is increased beyond the weight of the roof plates, the roof-to-sheU area goes into hoop compression. A small portion of the roof, the roof-to-sheU angle, and the top few centimeters of the sheU act as a compression ring to resist the unbalanced forces from internal pressure on the conical roof. The internal design pressure for this case may be... 

Pressure Tanks Vertical cylindrical tanks constructed with domed or coned roofs, which operate at pressures above several hundred pascals (a few pounds per square foot) but which are still relatively close to atmospheric pressure, can be built according to API Standard 650. The pressure force acting against the roof is transmitted to the shell, which may have sufficient weight to resist it. If not, the uplift will act on the tank bottom. The strength of the bottom, however, is limited, and if it is not sufficient, an anchor ring or a heavy... 

An approved safety valve is usually of the huddling chamber design. In this valve the static pressure acting on the disk area causes initial opening. As the valve pops, the air space within the huddling chamber between seat and the blowdown ring fills with pressurized air and builds up more pressure on the roof of the disk holder. This temporary pressure increases the upward thrust against... 

A great variety of PVC materials have been tested in the process thus far cable, cable trays, flooring material, window frames, artificial leather, packaging, pipes, flexible hoses, ring binders and roofing material. This indicates that the process is robust and can handle a broad range of PVC materials. In terms of chlorine content, there are no restrictions. With the completion of the pretreatment pilot plant, the contents of other plastics and metals may now be reduced significantly. 

Selected examples illustrating the shape of host 26 under various conditions are given in Figs. 39a-39c. The first parameter we choose to characterize the shape of 26 is the inclination angle of the phenyl rings readable at the gable of the roof-shaped molecule (graphical representation in Table 22). It indicates little variation [see... 

Rolling ball viscometers, 21 738 Roll mills, 16 722 Rolls, high pressure, 16 612-613 Romanechite, 15 540 Romascone, 24 571 Romet-30/Romet-B. See Ormetoprim ROMP catalysts, 17 707, 708 ROM polymers. See also Ring-opening metathesis (ROM) polymers, 26 947-948 Roof coatings... 

The examples cited above represent part of an increasing body of structural information on chlorophylls, chlorins, bacteriochlorins and isobacteriochlorins (10-14 and references therein) that points to the remarkable flexibility of these molecules This ability of the macrocycle to adjust is not limited to hydroporphyrins but is also observed in porphyrins 5,10,15,20-tetra-n-propylporphinato lead (II) assumes a "roof" shape by folding along an axis defined by two opposite methine carbons with the two planes of the "roof" inclined at 22 to one another (15) In contrast, triclinic 5,10,15, 20-tetraphenylporphinato cobalt (II) is distinctly saddle shaped with the 3 carbons of adjacent pyrrole rings lying 40 66 and -0 66A above and below the plane of the four nitrogens (16) ... 

Oh. I see. It s Claire Dryden here. I m the next-door neighbour and I m terribly sorry to ring so late but I just saw someone on your roof ... 

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