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.

Abstract: Apparatus for making ceramic tubes 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.