Abstract: An apparatus for controlling the web tension in a perforation-welding system for making bags from synthetic resin foil webs in which whistling noises are eliminated by passing the web over a wall of a polygonal duct having an air outlet opening to which compressed air is fed. The air cushion and hence the spacing of the web from the wall is measured by an ultrasonic detector on the opposite of the web.
Abstract: A system to synchronize the withdrawing and feeding motions of a flexible ribbon (1), including a synchronizing chamber (6) through which is running the flexible ribbon, that presents a curvilinear part with the concavity pointing upwards (10, 11) by means of the suction of a device (4) applied at the bottom of the synchronizing chamber (6). A proximity sensor (4) detects the position of the curvilinear part (10, 11) and controls the synchronizing of the withdrawal and feeding motions, continuous or intermittent, of the running flexible ribbon.
Abstract: Apparatus and method for coating a moving paper web, in which the web to be coated is first guided to a coating station correctly aligned and a first side of the web is coated with a coat layer. Next, the web is guided upwards from the coating station and the first coat layer is dried using non-contact dryers. From the dryers the web is guided to the next coating station correctly aligned, and the second side of the web is coated with a coat layer, the web is guided upwards from the coating station and the coat layer on the second side of the web is dried using non-contact dryers. When the web is directed from the coating station through the dryers, it is guided non-contactingly by means of air jets such that the web is first non-contactingly turned in the machine direction during drying and next, similarly during drying, towards the level of the coating stations.
Abstract: Apparatus and method for coating a moving paper web, in which the web (2) to be coated is first guided to a coating station (7) correctly aligned and a first side of the web (2) is coated with a coat layer. Next, the web (2) is guided upwards from the coating station (7) and the first coat layer is dried using non-contact dryers (8, 9). From the dryers the web (2) is guided to the next coating station (14) correctly aligned, and the second side of the web (2) is coated with a coat layer, the web (2) is guided upwards from the coating station (14) and the coat layer on the second side of the web (2) is dried using non-contact dryers (8, 9). When the web is directed from the coating station (7) through the dryers (8, 9), it (2) is guided non-contactingly by means of air jets such that the web (2) is first non-contactingly turned in the machine direction during drying and next, similarly during drying, towards the level of the coating stations (7, 14).
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