Apparatus for sealing

摘要

A first packaging strip(2) forming a cover film(6) is sealed onto a second packaging film strip(3) with product-filled naps. Both film strips pass between a feed roll(7) and a heated sealing roll(8). A preheater(10) for the first packaging strip upstream from the sealing roll has an electromagnetic radiation source in a radiation chamber(12) of a heating housing(11). The first packaging strip passes the radiation chamber. A sensor(15) monitors the atmosphere in the radiation chamber and the radiation chamber is closed in response to a sensor signal. The radiation chamber(12) is closed by a plate(16) moving in a straight path between the first packaging strip(2) and heating housing(11), in front of the radiation chamber. On the other side of the film there is a reflector(17) which also closes off the radiation chamber. Adjustment of the cooled reflector is in a plane perpendicular to the plane of the first packaging strip in front of the radiation chamber. The first strip passes through the housing at an angle to the vertical, preferably 15-45[deg], and the housing is parallel to the strip. A cylinder operated clamp(18) upstream from the radiation chamber holds the alignment of the first film strip. One or more venting channels(14) link the sensor(15) to the radiation chamber and the channels are connected to a vacuum unit. A pyrometer(20) is located downstream from the radiation chamber and is incorporated with the sensor in a control circuit governing the radiation source. The closure plate(16) and/or reflector operation are also included in the control circuit. The heating housing and feed roll(7) are connected to a cooling unit. Radiant heat is provided by a near infra-red lamp(13).