Apparatus for heat sealing of container bodies

#The invention herein is related particularly to packaging machinery of the type wherein closure of container flaps having heat sealable surfaces is effected by heated air directed against the surfaces to condition the same prior to closing of the container flaps.

#According to the invention the temperature of the heated air is modulated at a point remote from the point of entrance of such air to a tube supplying the heated air to a nozzle directing the air against the surfaces to be heated, so that it is not necessary to modulate the temperature of the heated air at the point where it enters the tube, the amount of temperature modulating air being a great deal less than the amount of air being supplied at the tube entrance.

#FIG. 1 is an isometric view of apparatus embodying features of the present invention; and

#FIG. 2 is an elevational view, certain parts being shown in longitudinal cross section.

#The apparatus according to the present invention is denoted generally by the reference numeral 10, and is shown in the environment of an endless packaging conveyor 11 having spaced trapping lugs 12 for trapping a container body CB therebetween. Container body CB has closure flaps CF thereon coated with a material adapted to be heated to a suitable temperature to a condition for subsequent sealing of one flap CF to another by structure, not shown, and well known in the art.

#In the heating of the flaps CF a blast of heated air is directed thereagainst by a nozzle 13 having openings 14 therein. Nozzle 13 is connected to a tube 16 supplying heated air to nozzle 13.

#Structure is provided for supplying a moving column of heated air to tube 16 and nozzle 13 and includes a fuel-air mixing device 17 connected to a source 18 of gaseous fuel by a supply line 19, there being a fuel supply adjusting valve 21 interposed in line 19 between source 18 and mixing device 17.