US 5,227,105 A · Process for manufacturing ceramic tubes

Abstract

Ceramic tubes are manufactured from a mixture that includes ceramic powder. The mixture is extruded through a die to form a tube. The tube is passed through an open-ended dryer, calciner, transition zone, sintering furnace, and cooler. Thereafter, the tube is cut to the desired length (which may be very long). The quality of the tube is enhanced by applying a vacuum to the mixture prior to extrusion. For tubes made of non-oxide ceramics, an inert atmosphere is maintained both inside and outside the tube in all sections of the equipment that operate above 200.degree. C. A controlled tension is applied to the tube by means of first pinch rolls disposed downstream of the dryer and second pinch rolls disposed downstream of the cooler.

Claims34

Dependent claims

A method of manufacturing ceramic tubes on a substantially continuous basis from a mixture including ceramic powder and organic material, comprising the steps of:

providing a die having a desired cross-section;
extruding the mixture through the die to form a tube;
supporting the tube after it has been extruded;
drying the tube while continuing to extrude the mixture;
supporting the tube while it is being dried;
calcining the tube at about 550.degree.-600.degree. C. to decompose the organic material while continuing the extrude the mixture;
supporting the tube while it is being calcined;
sintering the tube while continuing to extrude the mixture;
supporting the tube while it is being sintered;
cooling the tube while continuing to extrude the mixture;
supporting the tube while it is being cooled;
and
cutting the tube to length while continuing to extrude the mixture.

10 more elements

A method for manufacturing ceramic tubes from a mixture including ceramic powder and organic material, comprising the steps of:

providing a die having a desired cross-section;
applying a vacuum to the mixture;
extruding the mixture through the die to form a tube;
supporting the tube while continuing to extrude the mixture;
drying the tube at about 175.degree. C. while continuing the extrude the mixture;
calcining the tube at about 550.degree.-600.degree. C. to decompose the organic material while continuing to extrude the mixture;
sintering the tube at about 2250.degree.-2300.degree. C. while continuing to extrude the mixture;
cooling the tube while continuing to extrude the mixture;
cutting the tube to length while continuing to extrude the mixture;
applying tension to the tube while continuing to extrude the mixture, the step of applying tension being accomplished by providing first pinch rolls and engaging the tube with the first pinch rolls subsequent to the step of drying, providing second pinch rolls and engaging the tube with the second pinch rolls subsequent to the step of cooling, the second pinch rolls being operated such that tension is applied through the tube upstream to the first pinch rolls;
maintaining an inert atmosphere around the tube during the steps of calcining and sintering;
and
maintaining an inert atmosphere within the tube during the steps of calcining and sintering.

10 more elements

Dependencies are inferred from the claim text.

Process for manufacturing ceramic tubes

Life of this patent

Process for manufacturing ceramic tubes

Life of this patent

Abstract

Claims34