| 摘要 |
838,523. Filters. PRECISION MECANIQUE. March 7, 1958 [March 13, 1957], No. 7499/58. Class 46. [Also in Group XXVIII]- An annular filter element of pleated sleeve form is secured either externally or internally of a perforated blind ferrule mounted on a duct wall so as to project from or into said duct ; the sleeve having a flexible end flange whereby it is secured to said ferrule. As shown in Fig. 1 a paper sleeve 3 having longitudinal and radially extending pleats has plastic, rubber or leather end flanges 4, 5 turned to provide collars 4a, 5a which are tied by tape over imperforate end margins 1a 1b of a perforated blind ferrule 1 projecting from the underside of a clean fluid duct 2. The sleeve may be folded to provide pleats of herringbone formation, as shown in Fig. 5, wherein the upper end is tied to a short annular flange 20 in which is slidably mounted the ferrule 22 to the bottom end of which is tied the other end of sleeve 19. The ferrule tends to be forced upwardly against a spring 25 by back pressure developed due to clogging of the sleeve which is free to contract longitudinally and thus give a visual indication of the degree of clogging. In a modification a herringbone pleated filter element comprises a lining for the ferrule. |
