Method for making heat exchange matrix by crystallation

Claim 1

A method as defined in claim 1 in which a. said softening temperature is above the annealing temperature point of said tubes and interstitial glass and in a temperature range in which said tubes and interstitial glass nucleates during said expansion and fusion, and which further includes b. thereafter further heating the tubes and interstitial glass to a second temperature higher than said softening and nucleating temperature to effect crystallization of said tubes and interstitial glass into an integral fused matrix of glass-ceramic having a low coefficient of lineal thermal expansion.

Claim 6

A method for making heat exchange apparatus comprising an assembly of integrally fused tubes forming a series of smooth, longitudinal passageways therethrough, wherein the walls defining said passageways have essentially zero porosity and an average coefficient of lineal thermal expansion of about -18 to 50 X 10 7/*C, over the range 0*-300*C, which comprises a. bundling together into a desired configuration a plurality of elongated tubes made of a glass that is thermally crystallizable to a low expansion glass-ceramic having a coefficient of lineal thermal expansion of about -18 to +50 X 10 7/*C over the range 0*-300*C, each of the tubes being sealed at each end and containing an expansible fluid medium, b. providing in the interstices between the bundled tubes additional glass that is also thermally crystallizable to a low expansion glass-ceramic having a coefficient of lineal thermal expansion of about -18 to +50 X 10 7/*C over the range 0*-300*C, c. constraining the bundle of tubes against movement from the desired final configuration, d. subjecting said constrained bundle of tubes and the interstitially disposed additional glass to a temperature sufficient to soften said tubes and said interstitial glass and to cause said fluid medium entrapped in said tubes to urge said tubes into tight contact with adjacent tubes and said interstitial glass, thereby to aid the fusion of such tubes to each other and to said interstitial glass, said temperature being in the range of 50 to 250*F above the annealing point of said tubes and interstitial glass, in which temperature range said tubes and said interstitial glass nucleates during said expansion and fusion, e. thereafter jointly heating said tubes and interstitial glass at a rate of at least 50*F per hour to a higher temperature than the temperature in step (d) in the range of 200* to 500*F above said original annealing point, and f. finally heating said fused matrix in a temperature range of from 1,800* to 2,300*F and thereby completing crystallization thereof to a glass-ceramic having an expansion in the range aforementioned.