| 摘要 |
A gas heat exchanger comprises a rigid gas bypass tube 209 forming a gas passage, a concentric heat transfer tube 206 surrounding the gas bypass tube 209 and transferring heat between a gas and a fluid coolant, a tubular outer casing 100 encasing at least partially the heat transfer tube 206 and at least a portion of the bypass tube 209, and a plurality of helical undulations extending along a length of a wall of the heat transfer tube 206. Bypass tube 209 may be rigid enough to form a main load bearing component of the heat exchanger that may be installed in an exhaust system of a vehicle. The helical undulations may be provided with a plurality of secondary forms (fig 4) such as corrugations that comprise of a plurality of parallel ribs on the sides and on a crest of the helical ridges or within a valley between a pair of the helical ridges. The corrugations may comprise of scallop protrusions protruding from the sides of helical ridges (fig 7). The heat transfer tube 206 may comprise of a number of helix starts. Bypass tube 209 may have a smooth or helically formed outer surface. Outer casing 100 may have a plurality of bellows formations 203 for absorbing expansion or contraction, and an inlet and outlet pipe 104 for coolant. |
