Insert for a radiant tube
OwnerMartin R. Kasprzykinventor
Life of this patent
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Abstract
An integral ceramic insert for a radiant tube. The insert has a helical shape and contains ceramic material; and it has a thermal expansion rate of less than 6.0×10−6 meters/meter/degree Celsius and a thermal conductivity of at least 0.2 calories/centimeter/second/degree Celsius. The diameter of the insert is from about 2 to about 10 inches, and it has a length such that the ratio of its length to its diameter is from about 2/1 to about 8/1. The helical shape of the insert contains one or more pitches of from about 2 to about 32 inches, each which defines a helix angle of from about 15 to about 80 degrees.
Claims15
An integral ceramic insert for a radiant tube, wherein said integral ceramic insert has a substantially helical shape, and wherein:
- (a) said integral ceramic insert is comprised of at least 40 volume percent of a material selected from the group consisting of silicon, silicon carbide, silicon nitride, and mixtures thereof,
- (b) said integral ceramic insert has a thermal expansion rate of less than 6.0×10−6 meters/meter/degree Celsius,
- (c) said integral ceramic insert has a thermal conductivity, at a temperature of 25 degrees Celsius, of at least 0.2 calories/centimeter/second/degree Celsius,
- (d) said integral ceramic insert has a diameter of from about 2 to about 10 inches and a length such that the ratio of said length to said diameter of said integral ceramic insert is from about 2/1 to about 8/1,
- (e) said helical shape is comprised of one or more pitches of from about 2 to about 32 inches, each which defines a helix angle of from about 15 to about 80 degrees, provided that there is from about 0.5 to about 8 inches of pitch per inch of diameter of the integral ceramic insert, and
- (f) said ceramic insert has a cross-sectional shape defined by a centerpoint and extending radially outwardly therefrom at least one wing.
A radiant tube comprised of a first integral ceramic insert disposed inside of said tube, wherein said integral ceramic insert has a substantially helical shape, and wherein:
- (a) said first integral ceramic insert is comprised of at least 40 volume percent of a material selected from the group consisting of silicon, silicon carbide, silicon nitride, and mixtures thereof,
- (b) said first integral ceramic insert has a thermal expansion rate of less than 6.0×10−6 meters/meter/degree Celsius,
- (c) said first integral ceramic insert has a thermal conductivity, at a temperature of 25 degrees Celsius, of at least 0.2 calories/centimeter/second/degree Celsius,
- (d) said first integral ceramic insert has a diameter of from about 2 to about 10 inches and a length such that the ratio of said length to said diameter of said integral ceramic insert is from about 2/1 to about 8/1,
- (e) said helical shape is comprised of one or more pitches of from about 2 to about 32 inches, each which defines a helix angle of from about 15 to about 80 degrees, provided that there is from about 0.5 to about 8 inches of pitch per inch of diameter of the integral ceramic insert, and
- (f) said ceramic insert has a cross-sectional shape defined by a centerpoint and extending radially outwardly therefrom at least one wing.
Dependencies are inferred from the claim text.