GB894898A - Improvements in vapour generating plant - Google Patents

Abstract

894,898. Vertical steam generators; superheaters. BABCOCK & WILCOX Ltd. Feb. 16, 1961 [Feb. 20, 1960], No. 5785/61. Classes 123(2) and 123(3) In a steam generating unit consisting of an upright cylindrical pressure vessel 1 closed at its ends by domed end caps 2, 3 and containing helicoidal tube banks 19, 20 carrying the heating fluid, for example, the gaseous coolant from a nuclear reactor, the tube banks being disposed in a steam generating space above which is situated an annular steam and water collecting chamber 38 outlets 39 lead from the chamber to a battery of cyclone separators 40 mounted within a drum 33 whence separated steam ascends through driers 42 to a steam space 43 in the upper part of the drum whilst water is discharged by the separators 40 into a pool 41 and returned through an axially disposed downcomer 21 to a liquid inlet chamber 31 for recirculation. Steam leaves the space 43 through secondary drying units 44 and ascends through an annular passage containing a superheater tube nest 10 to leave the vessel 1 through outlets 50. The heating gas enters the pressure vessel 1 through an inlet 4 and is conducted by tubes 8 to the superheater tube bank 10 whence it passes through a pipe 15 and a distributor 17 to the tube banks 19, 20. From the latter the heating gas passes through a collector 24 to an outlet pipe 25 passing through the end cap 3 at the lower end of the pressure vessel. In a modification, Fig. 4, a number of boilers as described above may be arranged in pairs to form two horizontal rows, between which are disposed heating gas supply and collecting mains 70, 71, each boiler 1A being connected to an economiser 60A, wherein the heating gas leaving the boiler is used to heat feedwater flowing to the boiler. In a further modification, Fig. 5, not shown, a separate superheater is used in conjunction with each boiler and economiser unit.