| 摘要 |
A warmth keeping ceramic or porcelaneous vessel wherein a sealed airtight hollow chamber under a reduced pressure is formed between an inner vessel and outer vessel to keep contents warm. The hollow chamber is kept airtight under a reduced pressure by an enamel bonding the joint of the inner vessel and outer vessel or closing fine holes made in either of the inner vessel and outer vessel, after heating vessels to discharge the air in the hollow chamber through the joint or the fine holes. |
