FIELD: food industry; induction welding.
SUBSTANCE: proposed induction welder for packing material can be used in packing unit for continuous production of sealed packages with liquid food products at feeding of packing material tube in first direction. Proposed welder contains induction devices interacting with packing material through two first active surfaces and two second active surfaces. Second active surfaces are arranged between first active surfaces in first direction and are provided with bosses projecting in direction of packing material. Active surfaces have width in first direction and length in second direction square to first direction. Width of second active surfaces exceeds width of first active surfaces at least on greater part of length of first and second active surfaces. Carrying body of welder for arrangement of induction devices is made of aluminium-based material with inner layer of material concentrating magnetic flux and placed between induction devices and carrying body. Packing unit contains at least two pairs of grips periodically and successively acting onto tube, clamping the tube on equally spaced cross sections. Each pair of grips is provided with induction welder and cutter designed for cross cutting of tube in second direction. Said cutters has cutting member with base part and cutting tool whose thickness decreases in first direction as compared with base part. Cutting tool is connected with base part by section whose cross section increases in direction of base part and which is formed by outer concave surfaces. Relation of sizes of active surfaces provides uniform distribution of heat over entire cross section of tube clamped between grips, thus improving quality of welding, eliminating negative effect of pressing out of plastic melted at thermal welding from welding tape caused by overheating. Moreover, change of distribution of induced power over cross sections of tube at welding, especially, rise of power induced in extreme induction elements of each grip, makes it possible to dispense with inserts made of material concentrating magnetic flux on section of deflection of eddy currents and on intersection of cross welding zones and longitudinal weld on packing material tube. So, one welder can be used at welding packing material tubes of different width in manufacture of different types of packages of equal volume.
EFFECT: enlarged operating capabilities.
12 cl, 7 dwg
