Improvements in water-tube steam boilers

摘要

822,417. Water tube steam boilers. HUET, A. Aug. 8, 1957 [Aug. 14, 1956], No. 25062/57. Class 123(2) A water-tube steam boiler heated by hot fluid, for example, the coolant gas from a nuclear reactor, comprises a cylindrical casing a through which the fluid passes upwardly as indicated at A and which contains an economizer b, identical assemblies d, c of water tubes respectively constituting high andlow pressure boilers and a superheater f. Each boiler consists of a steam and water drum e and a water drum l disposed one above the other coaxially of the easing, the drums being respectively connected by tubes c1 k to rings of headers g, j of Which vertically corresponding headers are connected by vertical downcomer pipes m. Nine inclined sub-headers h, i extend respectively from each of the headers g, j flong radii of the cylinder a, vertically corresponding sub-headers h, i being connected by vertical steam generating tubes d. The tubes d are preferably finned as shown at s in Fig. 5 and contain tubes t through which the heating fluid passes, the working fluid being contained in the annulus between the tubes. A helical member disposed in contact with the outer tube only is aranged in the annulus to give the rising steam-water mixture a spining motion causing some separation of the water and steam, the latter passing upwardly along the inner wall of the annulus. Further separation occurs in the subheaders h and in the headers g. To give more efficient external-heating of the tubes s cruciform section core elements u having arms of undulating contour are disposed between the tubes. The bank of generating tubes may be prefabricated in sectors to reduce the site welding, The tubes in each sector increase in diameter from the inner to the outer ring to fill the space available completely whilst ensuring that the. tubes all operate under the same conditions as regards heat exchange.