Insulated double-walled exhaust system component and method of making the same
Assignee3M Innovative Properties Company
InventorRichard P. Merry
Life of this patent
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Abstract
A double-walled exhaust system component having hollow ceramic microspheres disposed between inner and outer pipes and method of making the same. The hollow ceramic microspheres have a size distribution wherein, on a bulk volume basis, at least 90 percent of the hollow ceramic microsphere have a size of less than 150 micrometers.
Claims16
An insulated double-walled exhaust system component comprising an inner pipe, an outer pipe surrounding the inner pipe, first and second annular seals connecting the inner and outer pipes and together with the inner and outer pipes defining an enclosed cavity, hollow ceramic microspheres packed within the cavity and having a size distribution wherein, on a bulk volume basis, at least 90 percent of the hollow ceramic microspheres have a size of less than 150 micrometers, and wherein the hollow ceramic microspheres have a true density in a range of from 2.0 to 2.1 grams per milliliter.
A method of making an insulated double-walled exhaust system component, the method comprising:
- providing an inner pipe;
- at least partially confining the inner pipe within an outer pipe;
- connecting the inner and outer pipes to form a fillable cavity having at least one opening;
- at least partially filling the fillable cavity with hollow ceramic microspheres having a size distribution wherein, on a bulk volume basis, at least 90 percent of the hollow ceramic microspheres have a size of less than 150 micrometers, and wherein the hollow ceramic microspheres have a true density in a range of from 2.0 to 2.1 grams per milliliter;
- and
- sealing said at least one opening and enclosing the hollow ceramic microspheres.
Dependencies are inferred from the claim text.