GB732204A - Improvements in or relating to methods of heat exchange and apparatus therefor - Google Patents

Abstract

732,204. Tubular heat-exchangers. FARRER, J. O. (Lummus Co.). Aug. 27, 1953, No. 23754/53. Class 64 (3). Relates to a method and apparatus for exchanging heat between two fluids through the medium of a third or intermediate fluid which is maintained in an independent space surrounded by one of the heat-exchanging fluids and surrounding the other of the two fluids and which is employed to detect leakage thereto of either of the heat exchanging fluids, the said independent space including at each end thereof an inner chamber in juxtaposition with an outer chamber, said inner and outer chambers respectively containing part of the intermediate fluid and part of the said other of said two fluids. According to the invention the intermediate fluid is contained in a closed outside circuit communicating at its opposite ends with said inner chambers, means being provided in said circuit to measure any significant change in a predetermined characteristic of the intermediate fluid to indicate leakage of either of the said two fluids. The intermediate fluid acting as a heat transfer medium may be circulated by a pump or allowed to remain static. Any or all of the fluids may be liquid or gaseous. The presence of leakage fluid or of rays or of electronic flux therefrom may be detected in the intermediate fluid by change in colour of the latter fluid or by change in odour, pressure, viscosity or by any other change whether physical or chemical. In the form shown one of the two fluids between which heat is exchanged flows between header 5 and tubes 12 to header 3 leading to outlet nozzle 15, andthe other of the heat exchanging fluids flows from inlet 18 through casing 1 over tubes 13 in a tortuous path as directed by baffles 32 to outlet 19. The intermediate fluid is contained in the annular spaces between concentric tubes 12, 13, headers 2, 4 communicating with these spaces and an external path including a pipe-line 23, 26, 16, pump 27, sight glass 28 preferably with flow indicating means, pressure relief valve 24 and electrical conductivity meter 29. Samples of the intermediate fluid may be drawn off through the tap 25 for inspection and analysis. Expansion joints 20, 21 permit relative expansion between the tubes and the casing.