摘要 |
<p>The heat exchanger consists of a series of oval-section tubes (12) with fins (14) and ends which pass through apertures in collector plates (20) with compressible seals (30) forming collars (34) round the ends of the tubes. The longer axis of each tube oval cross-section is the same along the whole of the tube, while the shorter axis is greater at the end of the tube, caused by an expansion of the tube as it passes through the collector plate aperture and seal. The expansion is produced by a tool (48) with a shaped tip (50) which is driven into the end of each tube after it has been assembled with the collector plate, compressing the seal against the sides of the aperture. The compression of the seal in a lengthwise direction is carried out before the tubes are fitted.</p> |