To provide a heat exchanger using a ceramic outer tube for a heat exchanger tube, capable of improving durability and being easily installed at low cost without reducing heat exchange efficiency, even when the heat exchanger is used in an environment or the like in which ashes and dust may be easily attached.
In the heat exchanger, which includes a heat exchanger tube 4 of a double-tube structure composed of a ceramic outer tube 2 the tip of which is closed and the rear end of which is opened and an inner tube 3 arranged with a gap from the inner wall of the outer tube 2 and opening the tip and the rear end to heat low-temperature gas G1 circulating through the heat exchanger tube 4 by heat exchange with high-temperature gas G2 circulating the outside of the heat exchanger tube 4, the outer tube 2 and the inner tube 3 of the heat exchanger tube are formed so that a vertical cross-sectional shape in a length direction from the tip to the rear end is an ellipse or a rounded rectangle and the gap between the outer tube 2 and the inner tube 3 is set so that an interval b in the major axis direction of the ellipse or the rounded rectangle is longer than an interval (a) in the minor axis direction.
YOSHIDA KAYOKO
SAKAI YUKIFUMI
Rie Ishimura