| 摘要 |
PURPOSE:To make accurate location of an inner cylinder in an outer and provide sufficient mechanical strength by forming the inner and outer cylinders consolidated with a support part, providing an air circulating part at one end of the inner cylinder, and thereafter sealing the end, and also protruding the open end of the inner cylinder from the outer. CONSTITUTION:An inner and an outer cylinder 2, 3 made of ceramic are coupled together by supports 4-1 thru 4-3 to form a consolidated structure, and at the tip 5 as one end the inner and outer cylinders 2, 3 are sealed with a solid sealing member 6. Air circulating holes 7-1 thru 7-3 are provided in a place of the inner cylinder 2 close to this sealing member 6, and at the opening of the other end the inner cylinder 2 is protruded a certain length from the outer 3 and the supports 4-1 thru 4-3. Thereby location of the inner cylinder 2 in the outer 3 can be made accurately, and sufficient mechanical strength be obtained. |
