Clay kneader

A clay kneader comprising a drum including:

• a supply opening through which a clay including a ceramic material flows into the clay kneader,
• a screw having a rotary shaft and a helical rotating blade provided along the rotary shaft and configured to knead the clay which has flowed into the clay kneader by the rotation of the rotating blade, and
• an extrusion opening from which the clay is extruded as a columnar article,
• wherein the drum includes a pressure raising section on the side of the supply opening, an extrusion section having an inner diameter smaller than that of the pressure raising section on the side of the extrusion opening, and a flow controlling section located between the pressure raising section and the extrusion section, the inner diameter of the flow controlling section is equal to that of the end of the pressure raising section on the extrusion opening side in the end of the flow controlling section on the supply opening side, gradually decreases toward the extrusion opening, and is equal to that of the end of the extrusion section on the supply opening side in the end of the flow controlling section on the extrusion opening side,
• the rotary shaft has a diameter which gradually decreases toward the extrusion opening in the flow controlling section, and includes a rotary shaft end section around a boundary between the flow controlling section and the extrusion section, and
• the rotating blade is formed from at least the inside of the pressure raising section to the vicinity of the rotary shaft end section.