| 摘要 |
PURPOSE:To improve the air current state within the chamber and improve the purification degree maintaining performance by setting th average air speed of purification air current at the working part at a value higher than that of the purified air current at the passage part, and providing air speed distribution adjusting means which makes the blow-off air speed at the working part larger as it approaches the passage part. CONSTITUTION:By operating blowers 15 and 16, external air passes through a prefilter 26 and is sucked up through an air suction port 27. Air fed out of a blast chamber 17 from the blower 15 for the working part is purified by a high performance filter 19 for the working part, and then blown off to the working part 14a within the chamber from the entire surface of the ceiling at the working part. Further, air out of the blower 16 for the passage to a blast chamber 18 is purified by a high performance filter 20 for the passage, and then blown off to the passage part 14b within the chamber from the entire surface of the ceiling at the passage part. In this case, the blow-off air speed at the working part is successively made larger as it approaches the passage part, thereby the lowering of the purification degree at the working part due to the influence of dust dispersed from the operator or air vortex, passing through the passage part can be prevented, and the purification degree maintainance performance can be further increased. |
