| 摘要 |
<p>A fuel burning heater comprising a burner for hydrocarbon fuel that produces corrosive products generated by the burning of the fuel, a heat exchanger for the corrosive products comprising sheet metal having a core of a corrodible first metal and surface coatings exposed to said corrosive products of a corrosion resistant second metal, and lock seam joints uniting the sheet metal at the margins. Each lock seam comprises corrodible edges each surrounded and encased by margins of adjacent sheet metal in lapped contact so as to be substantially gas tight at the corrodible edges. An example of such a metal sheet is a soft steel sheet with a ferritic stainless coating ("chromized").</p> |
