GB826989A - Improvements in heat exchanger and boiler construction for a sea water evaporator - Google Patents

Abstract

An evaporator of the "basket" type, such as is used aboard ship for distilling water, comprises a substantially vertical shell having a plurality of straight sides and a wide sideopening, provided with a detachable cover 38, through which the heat exchanger 18 can be removed from the boiler chamber C when it becomes necessary to clean the exterior of the heat exchanger or the interior of the boiler. Beneath the heat exchanger is disposed a sump 34. The heat exchanger has a generally cylindrical <PICT:0826989/III/1> <PICT:0826989/III/2> <PICT:0826989/III/3> wall provided with deep radially projecting corrugations 44 which define internal recesses 46 and external recesses 48. A ring 56 is welded to the bottom of the cylindrical wall of the heat exchanger; and the ring is secured to a cylindrical shell 58 which is bolted by flange 60 to the bottom of the boiler. Inside the heat exchanger is disposed a skirt 64, the lower part of which is imperforate, while the upper part 68 is perforate and joins the top header 54. The lower part of the skirt comprises a frusto-conical section 70, the bottom edge of which slides over the upper end of the inlet conduit 72 for the heating medium, e.g. steam. A collar 74 is secured to conduit 72, and this forms an annular trough which is packed with grease G to seal the connection between the heat exchanger and the conduit. When the heat exchanger is to be removed, cover 38 is detached, the bolts are unfastened from flange 60 and the heat exchanger and skirt are slightly lifted, as a unit, so that the bottom edge of the skirt will clear the top end of conduit 72; the unit is then withdrawn through the side opening of the shell. Sea water is introduced into the boiler through conduit 26. The steam, supplied through conduit 72, passes through the perforations in the upper part of the skirt, and then flows down through the recesses 46. Steamcondensate is received in sump 34, and is withdrawn through conduit 36. Boiling sea-water rushes up the recesses 48; and steam is separated from the mixture at the apex formed by conical plates 23 and 25. The hot water falls back to the lower part of the boiler. Steam, containing some entrained water, passes through conduit 20 and is introduced tangentially into chamber S where the water is separated out by centrifugal action. This water flows into sump 22 and drains away through conduit 24. Brine is discharged from the boiler through conduit 28. The steam from chamber S may be led to a second separating chamber, and then to a condenser. Specifications 674,385, 811,474 and 824,354 are referred to.