| 摘要 |
<p>1277588 Pleated filter D A G MARSHALL 19 Feb 1970 [13 Dec 1968] 59352/68 Headings BID and BIT [Also in Division D1] The pleats of pleated filtering material are held by spaced apart lines 42, ribbons or blobs of synthetic plastics material applied, in liquid form, to one or both surfaces of the filtering material immediately prior to pleating. The filtering material, e.g. filter paper, microglass paper, open-pore polyurethane foam or a random fibre mat, is drawn off a roll 10 by a roller 40 which nips the material against an idler roll 12. Means (not shown) may be provided between the roll 10 and the roller 12 to maintain the filtering material at a predetermined tension. The material passes between two headers 14, 16 each having a line of spaced nozzles supplied with molten polyethylene from a heated pressure container 20, additional thermostatically-controlled heaters 26, 28 being provided in the feed pipes 22, 24 leading to the headers 14, 16. Lines or ribbons 42 of molten polythene are deposited on both surfaces of the filtering material. Pleating is effected by an upper plate 34 cooperating with two lower plates 36 mounted beneath an opening 32 in a table 30. The rollers 12, 40 and the plates 34, 36 are formed with grooves or slots to accommodate the lines 42. An air jet through a nozzle 38 helps to produce the pleat and effect cooling of the polythene. Each line or ribbon of polythene may have a core of string, cord, wire or nylon to give added strength to the filtering material. Subsequently, a metal grille or mesh may be bonded to the filtering material by heating the grille or mesh and pressing it against the polythene ribbons.</p> |
