Method of plugging the ends of selected ducts and a paste for use in said method
AssigneeSociete Anonyme dite: Compagnie Generale d'Electricite
InventorsGuy Kaltenbach, Pierre Lerner
Life of this patent
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Abstract
A method of plugging the ends of selected ducts (5) in a ceramic structure (1). A paste (8, 9) is prepared from a powder and a liquid. The powder comprises a glass whose coefficient of expansion is close to that of the ceramic structure. The liquid comprises a solvent, a plasticizer and an additive which reduces the adherence of the paste to a paste applying tool (6, 7). The tool is used to push paste into the ends of the selected ducts and the ceramic structure is subjected to heat treatment to ensure that the paste adheres to the walls of the ducts and then becomes solid.
Claims18
A method of plugging the ends of selected ducts in a ceramic honeycomb heat exchange structure, the method comprising the steps of:
- preparing a paste comprising a mixture of a solid phase and a liquid phase, the solid phase comprising powder of a glass whose coefficient of expansion is close to that of the ceramic structure and the liquid phase containing a solvent, a plasticizer and an additive which reduces the adherence of the paste to a paste-applicator tool;
- using an applicator tool to push said paste into the ends of selected ducts which are to be plugged;
- and
- heating the ceramic structure to fire the paste to cause it to sealably adhere to the walls of the ducts and become solid such that the closed ducts of said ceramic honeycomb heat exchange structure remain perfectly sealed during use irrespective of thermal expansion and contraction of the heat exchange unit.
A paste compound for sealably plugging the ends of selected ducts in a ceramic honeycomb heat exchange structure, said paste comprising a solid phase which contains powder of a glass with a coefficient of expansion close to that of the ceramic structure and a liquid phase which contains a solvent, a plasticizer and an additive to reduce the adherence of the paste to a paste applicator tool employed for pressure application of said paste into the ends of said selected ducts of said ceramic honeycomb heat exchange structure.
Dependencies are inferred from the claim text.