Corrosion resistant sintered iron-silicon filter

Claim 1

A HOLLOW STRUCTURAL FILTER ASSEMBLY CHARACTERIZED BY IMPROVED RESISTANCE TO CORROSION BY SULFUR-CONTAINING ATMOSPHERES AT ABOUT 950*F. AND FORMED OF A PLURALITY OF POROUS FILTER ELEMENTS COMPRISING SINTERED IRON-SILICON POWDER OF SIZE LESS THAN 60 MESH CONTAINING 10% TO 60% SILICON AND THE BALANCE SUBSTANTIALLY IRON, AND HAVING AN APPARENT DENSITY CORRESPONDING TO ABOUT 50% TO 80% OF THE IRON-SILICON ALLOY, SAID FILTER ELEMENTS BEING HELD IN END TO END ABUTTING RELATIONSHIP BY MEANS OF A HEAT RESISTANT METAL FRAMEWORK CHARACTERIZED BY AN AVERAGE COEFFICIENT TO LINEAR THERMAL EXPANSION OVER THE TEMPERATURE RANGE OF 0* TO 1200*F. OF AT LEAST ABOUT 5 BUT NOT EXCEEDING 7.5 MICROINCHES PER INCH PER DEGREE F.