| 摘要 |
PURPOSE:To provide a compact heat exchanger which can display a good heat exchanging performance by integrally disposing multiple internal fins for forming divided flow passages in a radial arrangement to an outer heat conducting pipe having outer fins and the outer surface of an inner heat transfer pipe contained in the former, and causing the tip of the inner fins to be fixedly contacting the inner surface of the outer heat transfer pipe by expanding the inner heat transfer pipe. CONSTITUTION:Outer fins 2a are formed on the outer surface of the middle part by rolling. There are eight internal fins 3a for forming divided passages which are radially arranged when viewed sectionally inside the outer heat transfer pipe 2 having a circular section profile, said internal fins 3a being integrally formed. The tips of the internal fins 3a are fixedly contacting the inner surface of the outer heat transfer pipe 2 by pipe expansion. Between the outer heat transfer pipe 2 and internal heat transfer pipe 3, eight divided flow passages for engine oil are formed which are independent to each other and extend parallelly with the axis of the internal heat transfer pipe. There is no need for facilities and engineering for brazing in oven, and continuous manufacture become possible. It is advantageous from a view point of cost, and there is little fear for liquid leakage. Further, a heat exchanger can thus be provided which is compact and yet is superior in the heat exchanging performance. |
