| 摘要 |
PROBLEM TO BE SOLVED: To improve cooling ability of a seal bar by a small tank. SOLUTION: In order to improve cooling ability by a small tank, an on/off valve 37 which closes a main vacuum line 35 while a pressure resistant chamber 30 is opened is provided on the main vacuum line 35 for connecting the chamber 30 with a vacuum pump 36. In addition, an open end of a sub vacuum line 40 branching between the pump 36 and the valve 37 is opened on a ceiling surface 44 of an airtight tank 43 reserving a liquid 42 on an internal lower layer. An end of a liquid circulating line 48 passing through a passage in the seal bar 51 placed in the chamber 30 is coupled with a lower layer of the tank 43 and the other end of the line 48 is coupled with an upper layer of the tank 43, respectively. Suction force of the vacuum pump 36 always works to the tank 43, so that an air layer 45 is changed into a vacuum environment to vacuum-cool the liquid 42 by exchanging heat with an upper surface of the liquid 42. |
