Patent ID: 6889487

Claim:
A sealing apparatus, comprising: a pair of upper and lower seal blocks ( 22 , 23 ) located across a transfer track of a tube file ( 20 ) accommodating materials ( 21 ) at equal spaces, for clamping the tube film between the materials; a pair of seal bars ( 35 ) provided inside skirt parts ( 39 ) of the seal blocks ( 22 , 23 ); a cutting edge ( 51 ) attached to one of the seal bars ( 35 ); an edge receiving groove ( 52 ) formed in the other of the seal bars, for receiving the cutting edge to cut the tube film ( 20 ); and narrow continuous standing gaps ( 46 ) formed in part of a space between opposite edges of the respective skirt parts, whereby air in a front tube film in a transfer direction of the film is evacuated to the outside of the seal block through the edge receiving groove ( 52 ), wherein (a) each of the narrow continuous standing gaps ( 46 ) formed by cutting the opposite edges of the respective skirt parts comprises a pair of upper and lower teeth ( 44 , 45 ) opposing to each other, and one of a plurality of parallel air passage portions formed between the respective adjacent pairs of teeth, while a plurality of ports ( 47 ) respectively formed on opposite sides of the narrow continuous standing gaps ( 46 ) are connected to a vacuum tank ( 61 ) having a vacuum pump ( 60 ) as a vacuum source thereof, via a sub-vacuum line ( 49 ), and a first opening and closing valve ( 62 ) is provided in the sub-vacuum line ( 49 ) and a second opening and closing valve ( 64 ) is provided in a main vacuum line ( 63 ), (b) when the pair of seal blocks clamp the tube film and the cutting edge cuts the tube film, substantially simultaneously the first opening and closing valve is opened to separate apart upper and lower faces of the cut portion of the tube film alone the narrow continuous standing gaps by means of vacuum suction force acting on the sub-vacuum line, and intermittent air holes for evacuating air from the tube film are formed in the tube film along the parallel air passage portions by the separating action, and (c) the second opening and closing valve is opened slightly later than the opening of the first opening and closing valve, and air inside the front film to be evacuated to the outside of the seal block through the cutting edge receiving groove is sucked through the main-vacuum line connecting the seal block and the vacuum tank.