GB939511A - Improvements in or relating to diaphragm regulating valves - Google Patents

Abstract

939,511. Valves. EMILE EGGER & CO. A.G. March 1, 1960 [March 12, 1959; Sept. 30, 1959], No. 7137/60. Class 135. A valve consisting of elements that are movable in a plane perpendicular to the axis of a flow passage to define an opening of adjustable size but of constant shape is provided with means for preventing the lodgement of dirt &c. on the movable parts. In one embodiment, a polygonal opening is formed by e.g. six movable elements 7, Figs. 1, 2, which are guided by projections 18 slidable in rectilinear slots 19 in part of the housing and caused to move by rotary motion imparted by a screw and nut mechanism 25, 26 to a ring 13 having curvilinear slots 12 engaged by rollers 11 carried by the movable elements 7. That edge of each element 7 that forms a boundary to the polygonal opening is of convex form and has relative sliding engagement with a mating, concave edge of an adjacent element, sharp edges being provided at the corners 10 to give a scraping action along the convex edges. To prevent lodgement of dirt the slots 12, 19 are open-ended, the width of the bearing surface 14 for the ring 13 is less than the depth of the slots 12, and transverse grooves 12<SP>1</SP> are formed at the inner end of each slot 12. Straight grooves 24 in the ring 13 provide scraping edges to cleanse the elements 7. These elements, which are also scraped where they pass between annular grooves 9 in surfaces 5, 6, may themselves be grooved to scrape the surfaces 5, 6. Impurities, e.g. fibrous material, collecting in the grooves 9 ultimately form a felt-like packing. Flushing of the interior of the housing is facilitated by the provision of two nipples 23. A pointer 28 carried by the nut 26 and visible through an aperture 29 indicates the degree of opening of the valve. The co-operating surfaces of adjacent elements 7 may be shaped as at 55, 56, Fig. 4, which Figure also shows how the convex portion of each element may be formed as a separate strip 51 pressed against the adjacent element by a resilient body 53. Sealing rings 58, Fig. 5, may be used to prevent leakage between the elements 7 and the surfaces 5, 6. Further, a sealing ring 64, Fig. 6, may be provided in an annular recess 60 in the ring 13 and pressed into engagement with the elements 7 when the valve is closed by a ring 62 which has a camming engagement with the ring 13.