GB994326A - Improvements in or relating to heat exchangers - Google Patents

Abstract

994,326. Tubular heat exchangers. SVENSKA MASKINVERKEN AB. Nov. 16, 1962 [Nov. 18, 1961], No. 43419/62. Heading F4S. In a heat exchanger, such as an oil preheater or cooler, comprising a pair of substantially concentric tubes, the inner tube 1 carries uniformly spaced pin-fins 12 which project across the annular space between the two tubes, and the path of fluid flowing through the annular space is lengthened by means of axially spaced transverse baffles of part annular form, a slot through each baffle being angularly staggered with respect to the slots in the adjacent baffle(s). In an oil preheater as shown, Figs. 1 and 3, steam enters the apparatus through a pipe 3 and passes along the inside of the inner tube 1 to a discharge connection 5. Oil enters the annular space 9 through an inlet connection 10, and leaves through an outlet 11. A longitudinal partition 13, Fig. 3, extends along the annular space, its edges contacting the inner tube 1 and the outer tube 2 respectively. A series of baffles 14 extend transversely across the annular space, each having a slot or cutout section 15 bounded by radial edges 16 and 17 of the baffle. Every other baffle 15 has its edge 16 against one side of the partition 13, while the intermediate baffles 15 have their edges 17 against the other side of the partition, thus providing a tortuous path for the oil. Each baffle 15 consists of two arcuate sections 18, 19, pivotally joined by a rivet 20, and a spring 21 holds each baffle against the inside of the outer tube 2, and in its correct angular position. In an alternative form of baffle, Fig. 5, each baffle 22 is a single plate with a section cut out, bounded by mutually parallel edges 23 and 24 tangential to the inner tube 1, the cut-out in each baffle being displaced by 180 degrees from the cut-out(s) in the adjacent baffle(s). The baffles 22 are held in position by springs 26, 27 engaging slots 25 in the baffles. The spacing of either type of baffle may be altered after removal of the inner tube 1 from the outer tube 2, and a closer spacing may be employed at the end of the apparatus at which the oil is hottest, as in Fig. 1. The rows of pins 12 prevent axial movement of the baffles. A series of arcuate baffles may be arranged to give an approximately helical oil path through the annular space.