| 摘要 |
PURPOSE:To extend the life of a sealing material by making a sliding surface facing the sealing material of ceramic. CONSTITUTION:A cylinder 24 of a vacuum heat insulation tub 1 has at its head portion an air intake port 5 and an air exhaust port 6. A piston 9 is installed to be freely reciprocated in the cylinder 24. A rear end portion of the piston 9 is provided with a rider ring 10 for guiding the movement of the piston 9 and a sealing mechanism 11. The sealing mechanism consists of a groove 12, an O-ring 13 installed in the groove 12, and a sealing member 14. The rider ring 10 and the sealing member 14 are made of a self-lubricating material. Here, since the cylinder 24 is made of ceramic (e.g. silicon nitride), abrasion of the sealing member 14 and the cylinder 24 can be favorably reduced. |
