GB982300A - Improved heat exchange apparatus - Google Patents

Abstract

982,300. Plate-type heat exchangers. FREEMAN TAYLOR MACHINES Ltd. Nov. 1, 1962 [Aug. 3, 1961], No. 28166/61. Heading F4S. A heat-exchanger comprises an outer cylindrical casing A having an inner coaxially disposed cylinder B extending through it, and in the annular space 1 so formed are arranged two helical elements H 1 , H 2 , having their successive convolutions interleaved to provide two separate helical flow paths for the respective heatexchange media, the said helical elements having their outer and inner edges in sealing relation with the inner and outer walls of the outer casing and inner cylinder respectively. As shown, helical elements H 1 , H 2 are threaded together and then subjected to axial compression until adjacent flanges 2C meet. The helical elements are made up of circular plates 2, e.g. of 16 s.w.g. material having a central aperture. The plates are cut along a straight radial line extending from said aperture to the outer periphery of the plates, the split portions of said plates being displaced axially, and a cut radial edge of each plate is welded to an opposite radial edge of an adjacent plate so as to produce a helix. Each plate is formed with radially extending convex and concave tapered indentations 23, 24 to impart turbulence to the heat-exchange media flowing through the helical paths F 1 , F 2 . The inner edges 2a of the helical elements are in sealing contact with the outer sleeve 8, e.g. of silicon rubber, of the inner cylinder B. The sleeve 8 is mounted on a thin metal tube 7 which has its opposite ends closed by plates 9, 10. When the elements are in position on the inner cylinder B the tube 7 is subjected to internal hydraulic pressure through holes 12, 13 in end-plate 10, which causes permanent deformation of the tube and effects a permanent seal between sleeve 8 and the edges 2a of the helical elements. In a modification the inner cylinder may consist solely of a suitable moulded rubber tube which is filled permanently with water and compressed axially to force the wall of the tube outwards against edges 2a. The assembled elements H 1 , H 2 are encased in a sleeve 14 of resilient material, e.g. silicon rubber, which has a sheet-metal wrapper 15 around it. The wrapper is capable of being tightened by means of axially extending rods 16 (Figs. 2 and 5, not shown) which are connected with the opposite edges of the wrapper 15 and are drawn together by means of studs. Two sectoral shaped headers 5 are provided at each end of the head exchanger (Fig. 6, not shown).