| 摘要 |
<p>Inner cases (4, 20, 31) are connected to outer cases (5, 21, 32) through joining flanges (25, 26, 40, 41) which protrude toward outer peripheries of the outer cases (5, 21, 32). A plurality of combinations each including filters (2, 3), the inner cases (4, 20, 31), and the outer cases (5, 21, 32) are provided. Both the joining flanges (25, 26) (40, 41) are sandwiched and fixed between a pair of sandwiching flanges (51, 52) (53, 54), thereby connecting the plurality of outer cases (5, 21, 32) to each other.</p> |
