DE1604607A1 - Device for welding the layers of thermoplastic plastic films - Google Patents

Description

Device for welding the layers of thermoplastic plastic films.

The invention relates to a device for welding the layers of thermoplastic plastic films with an electric heat radiator, preferably in the form of an electrical resistance wire in a quartz tube.

For welding the front edges of layers of thermoplastic material lying on top of one another Material it is already known to use electrical resistance wires in a reasonable distance from the ones to be welded Front edges are arranged. This front edge weld, with the Nitzestraight parallel is directed towards the film surfaces, required for their implementation comparatively complex devices. Care must be taken that the foils on the front edges, at which they are welded together, are also in tight contact. Provided that is not the case, then the front edge welding cannot take place, because, as a rule, foils do not lie tightly at the edges, but only in one distance from the edge.

In practice it is difficult with moving foils, in particular in the form of already finished bags, on a conveyor belt the distance between the ones to be welded Strictly adhere to the front edges with the radiant heater. Unless by transport a lateral shift or a certain tilt of one behind the other on one Belt-guided bags or sacks are carried out and thereby the distance from those to be welded Front edges to the radiant heaters are different, which is usually unavoidable then the front edge weld is different over the length of the weld seam.

The present invention is based on the task of welding Thermoplastic plastic films to be used by heat radiation when welding of the layers of thermoplastic plastic films due to the action of tHarmecden Heat rays perpendicular to the foil surfaces.

To solve this problem, a device for welding the layers of thermoplastic plastic films with an electric heat emitter, preferably in the form of an electrical resistance wire in a quartz tube proposed according to the invention that the electric heat radiator in a water-cooled Bar of high thermal conductivity, in particular a copper alloy, is arranged, on the side facing the foils to be welded one over having the length of the radiator extending slot, through the width of which the Width of the weld seam is determined.

The proposal according to the invention to arrange the heat radiator in a rod, this rod-shaped housing having a slot through the width of which the The width of the weld seam to be produced is determined, leaves a surprising number of possible applications to and greatly simplifies welding devices previously considered necessary.

With the aid of the solution according to the invention, a longitudinal seam weld can be achieved take place in which the extension of the weld seam in the direction of the welding moving film (longitudinal weld seam). However, it can also have an ouer towards it the moving film arranged weld seam (transverse weld seam) can be attached. The solution according to the invention can also be used for closing bags or Sacks, but also for dividing a hose, especially one directly from a Extruder exiting hose, into several individual hoses.

According to a further inventive feature it is proposed that that in the rod there are two or more slots which determine the width of the weld seam are. Thus, even with a radiant heater next to each other in the width exactly dimensioned weld seams can be made with a desired spacing, with in A separating cut can be made in the film area between the weld seams can. However, it is also possible, with a correspondingly wide weld seam ' this width being determined by the width of the slot in the rod, a separating cut to be attached by a knife or an incandescent tape in the area of the weld seam.

According to a further inventive feature it is proposed that that the rod on its side facing away from the welded foils also is open and the outer surface of the quartz tube facing this open side is provided with a reflective layer, in particular made of a gold plating. This suggestion favors cooling because the quartz tube is used in addition to water cooling is air-cooled through the access that is open at the top. However, to one or only one Suffering little loss of radiant heat is the outer surface of the quartz tube on the side facing away from the foils to be welded with a reflective Layer provided.

Instead of the reflective layer on the jacket surface of the quartz tube can also be placed above the quartz heater in the rod or one of them on the staff The reflector pointing towards the slot in the rod should be present.

The solution according to the invention also allows inside the rod to arrange two quartz radiators arranged one above the other, the quartz tubes then advantageously 8-shaped, are in one piece and above this quartz radiator a reflector is arranged. This solution ensures that the upper quartz radiator contributes to the heating of the lower quartz heater and thus in particular with the Welding of thick foils within a short period of time sufficient radiant heat is available.

According to a further modification according to the invention, it is proposed that that two quartz radiators are arranged next to one another within the table, whereby the quartz tubes 6-shaped are in one piece and the upper half of both Quartz tubes are provided with a reflective coating, in particular gold coating and furthermore the rod has a slot associated with each quartz tube, which determines the width of the weld seam. By this proposal it is achieved that one Assigned to each weld seam to be produced, in the case of weld seams lying next to one another a quartz heater is available.

To cool the rod by water cooling, the rod can have cooling channels have that are integral with this. This can be achieved by continuous casting of the rods or in the case of cast Rods by inserting them accordingly of cores into the mold. Are particularly advantageous for cooling the rod whose longitudinal sides are arranged with semicircular grooves in cross-section, in each of which associated cooling line pipes are attached. This solution is very inexpensive to manufacture despite one-off production.

According to a further inventive feature, several rods be arranged with quartz radiators next to each other at a variable distance. In the end it is proposed to arrange a rod with a quartz radiator in a rotating drum, the drum having a surface extending in the axial direction Has slot for the passage of the welding beams.

This solution is intended for producing weld seams that extend transversely to the direction of movement of the film during processing. Included the slot in the drum wall can determine the width of the weld seam.

According to a further inventive feature is to provide ; uerschweißungen suggested that the rod with the Ouarzrohr, preferably two around 1800 staggered rods with blarz tubes arranged on a rotating shaft and there is a second shaft with spring-loaded rods provided with quartz tubes is, where. during the rotation of the rods assigned to the various shafts, these rest against each other on part of their circumferential movement. This proposal will in the same way as when using the rods with the Ouarz radiator in a drum, the application of quartz welds in continuously moving film webs enables.

The invention is shown in the drawings using a few exemplary embodiments explained in more detail. It is not limited to the forms of training presented, rather, further modifications within the scope of the invention are possible. It show: Fig. 1 schematically the welding of the front edges lying one on top of the other Layers of thermoplastic material of the previously known type according to a in side view and b - d in top view, FIG. 2 schematically shows the welding of film layers in a distance from the edges with a radiation direction perpendicular to the film surfaces in Fig. 1 corresponding view, Fig. 3 shows a device according to the invention in perspective Representation, FIG. 4 shows a vertical section through a modified version according to the invention Device, FIG. 5 a vertical section through a further modification, FIG. 6 a vertical section through a further modification, Fig. 7 a vertical section through a further modification, FIG. 8 in perspective Representation of the arrangement of several heat radiators according to the invention, FIG. 9 in a perspective view of the application of the solution according to the invention in a rotating welding drum, Fig.10 a further application of the invention Radiant heater in front view.

Fig. 1 shows with a designated in a front view two superimposed Foil layers 10 and 11 which are provided with a front edge weld 12. These Front edge welding is obtained by a sealing bar 13, which is used for: Example two insulated electrical resistance wires embedded therein can be heated is + This sealing bar 13 is arranged at a small distance from the front edges and through the heat radiation of the sealing bar described above, the front edges become fused together.

However, it is not as easy to use in practice as in the Drawing shown because hold-down devices are not shown in practice in the drawing be used to attach the film layers 10 and 11 in the area of the Front edge welding 1? to lay close to each other. Furthermore, special stops are provided to the To be able to adjust the distance between the sealing bar 13 and the front edges exactly. These exact setting is only useful if two layers of film, as in Fig. 1 with b, have an alignment of the longitudinal edges to be welded that are parallel to the direction of movement shown by arrow 14. If according to Fig. lc and FIG. 1d tilting takes place during transport of the film layers to the welding device in practice cannot be avoided, then the sealing bar 13 not aligned parallel to the front edges to be welded, with the result that that, as shown in FIGS. 1c and d, the front edge weld 12 does not extend over the entire edge length extends or with a lesser deviation of the orientation of the Front edges the width of the weld bead 12 is different over the length of the front edges is.

Fig. 2 shows that the heat rays with the solution according to the invention brought into action perpendicular to the film layers to be welded thus the Weld seam must be attached at a distance from the front edges. This will be the disadvantages described in connection with FIG. 1 are avoided with simple means. An angular position the front edge to the transport direction 14 is harmless, since a sufficient The distance between the longitudinal weld 15 and the front edges is always a uniform width Layer welding enables.

Fig. 3 shows the device according to the invention for welding layers. There is the rod 16, which is preferably integrally hollow on the inside for receiving a quartz radiator 17, consisting of a quartz tube 18 with an inside arranged resistance wire 19. The rod 16 has to accommodate the quartz radiator 17 a sufficient interior space so that between the outer wall of the quartz heater and the inner wall of the rod is sufficiently spaced apart.

The quartz radiator according to FIG. 3 has on its upper lateral surface which is directed away from the film layers 10 and 11 to be welded together, a Reflection layer in the form of a gold plating 20. The rod 16 has on its the side facing the film layers 10 and 11 extends over the length of the quartz radiator extending slot 21, the width of which determines the weld seam. A broad one A slot results in a wide weld seam, a narrow slot results in a narrow one Weld seam The rod 16 is water-cooled and points to both sides of the quartz heater Cooling duct 22 open. According to Fig. 3, the rod 16 is open at the top to open through this opening 23 to contribute to cooling.

In many cases, the arrangement can only be one rod according to the invention with quartz radiators for welding two layers are sufficient. Particularly beneficial However, two opposing rods with quartz radiators are arranged between where the photo layers to be welded are carried out, like that in Fig. 3 is shown. The surfaces of the rods that are trimmed to the film layers can be present at a short distance from the outer surfaces of the film layers 10, 11, but they can also rest on the soot surfaces of the film layers.

Bus Fig. 3 it can be seen that the solution according to the invention can be used is for film layers that are moved in the axial direction of the rods 16 and thus a Longitudinal welding result, but also in the case of foil layers in the direction of the arrow 25 are moved transversely to the longitudinal extension of the rods 16, so that transverse welds 26 can be obtained.

4 to 6 show various modifications of the invention Basic proposal. The rod 16 is water-cooled by two attached to the long sides, Cooling lines 27 laid in semicircular grooves. Also in this design the rod 16 is open at the top. The width 21 of the slot on the rod side that the Is prepared to be welded film layers, measures the width of the Weld.

Fig. 5 shows the embodiment of FIG. 4 with the modification that two adjacent slots 21 are present.

This is achieved by a longitudinal bar 22, the one wide slit divided. This bar 22 advantageously consists of either one very high temperature resistant material, or it is water-cooled.

Fig. 6 shows the arrangement of two superimposed quartz radiators, An 8-shaped one-piece quartz tube is present and assigned to each tube Resistance wires 17 are assigned. Above the double quartz heater is a semicircular curved one extending over the length of the quartz radiator Reflector 29 available. By the design and arrangement shown in FIG of the double quartz radiator it is achieved that the radiation of the upper quartz radiator superimposed with the radiation of the lower quartz radiator and thus a special one intense radiation effect is achieved, which makes it possible to be appropriately thick Welding foils together or thin foils within very short ones Time.

In the arrangement according to FIG. 7, a double quartz radiator is flat arranged lying down. Here are the outer surfaces of the uarz pipes at the top a gold plating 20 understand.

There is again a preferably water-cooled bar 28, which divided a wide slot so that there are two slots 21 in the rod 16, which lead to two side by side and longitudinal weld seams 15.

Fig. 8 shows that several rods 16 according to the invention design side by side are arranged. They are attached to rails 29 and 30, which are in the embodiment are located at the head ends of the rods 16 and transverse to the longitudinal extent the Rods 16 run. These rails 29 and 30 are provided with elongated holes 31 to to be able to adjust the lateral distance of the rods 16 variably. According to Fig. 8 are the radiators designed according to the invention are used, for example, for subdividing a film tube 32 by longitudinal welding into several individual tubes, Fig. 9 shows a solution for applying transverse welds 26 with continuously moving Sheeting. For this purpose, the to be welded together, in the direction of the arrow 31 continuously moving foils guided below the pulleys 34 and 35, so that they bear against part of the circumference of the welding roller 36 as they migrate. The jacket surface 37 of the welding roller 36 is provided with an axially extending 3 slot 38 provided. A is arranged inside in the vicinity of the slot 38 Rod 16 with a quartz radiator.

The slot 21 in the rod 16 can be omitted if the slot 38 is so is dimensioned so that its slot width determines the width of the weld seam. It is also possible to dimension the slot 38 larger5 and as an effective slot width to select the previously described slot 21 on the rod 16.

Fig. 10 shows that rods 16 offset from one another by 1800 in each case Quartz radiators and opening slots 21, which determine the width of the weld seam, are arranged on associated shafts 39 and 40. The shaft 39 rotates in the indicated Direction of arrow 41 and the shaft 40 in the indicated Direction of arrow 42. The rods 16 - lead those represented by the indicated circles 43 and 44 Circumferential movements. The shafts 39 and 40 rotate synchronously. This takes place in each case at a revolution of 1800, the rods 16, which support the shafts 39 and 40 are assigned and through this a welding of the intermediate, specified in Direction of arrow 45 moving foils. To a plant of the rods 16 not only in the apex to achieve, provided that on a circular sector, the circular movements overlap 43 and 44.

To make this possible, the rods attached to the shaft 40 are 16 mounted on associated springs 46 so that they give way downwards when the system is in place.

Claims (11)

Claims 1. Device for welding the layers of thermoplastic Plastic films with an electric heat radiator, preferably in the form of one electrical resistance wire in a quartz tube, d u r c h g e k e n n z e i c h -n e t that the electric heat radiator (17) in a water-cooled Rod (16) of high thermal conductivity, in particular a copper alloy, is arranged is, the one facing on its side facing the foils to be welded the length of the radiator (17) extending slot (21) by its width the width of the weld seam (15, 16) is determined. 2. Apparatus according to claim 1, d a d u r c h g e k e n n z e i c h n e t that in the rod (16) two or more determining the width of the weld seam Slots (21) are available * 3. Device according to claims 1 and 2, d a d u r c h g e k e n n n z e i c h n e t that the rod (16) is to be welded at its the Foils (10, 11) facing away side is also open and this is open Side facing cantilever surface of the quartz tube with a reflective layer (20) is provided in particular from a gold plating. 4. Device according to claims 1 and 2, d a d u r c h g e k e n n z e i c h n e t that above the quartz radiator (17) in the rod (16) or on Bar on its rays to the Slot (21) in the rod pointing reflector (29) is present. 5, device according to claims 1, 2 and 4, d a d u r c h g e k It is noted that within the rod (16) two arranged one above the other Quartz radiators (17) are arranged, the quartz tubes 8-shaped in one piece and a reflector (29) is arranged above this quartz radiator. 6. Device according to claims 1, 2 and 3, d a d u r c h g e k It is noted that within the rod (16) two quartz radiators (17) next to one another are arranged, wherein the quartz tubes 8-shaped are formed in one piece and the upper half of both quartz tubes with a reflective support (20), in particular Gold plating, @ urid the rod is still assigned to each quartz tube has a slot (21) which determines the width of the weld seam (15 or 26). 7. Device according to claims 1 to 6, d a d u r c h g e k e n n z e i c h n e t that for cooling the rod (16) on its longitudinally extending Sides in cross-section semicircular grooves are arranged, in each of which associated cooling line tubes (27) are attached. 8. Device according to claims 1 to 7, d a d u r ch g e = e n n e i n e t that several bars (16) with O @@, @@@ ahlern (17) next to each other at a variable distance 9. Device according to claims 1 to 7, d a d u r c h e k e n n n z e i c h n e t that a rod (16) with quartz emitter (17) is arranged in a rotating drum (36), the drum in its Manteiffläche a slot (38) extending in the axial direction to the passage that has heat rays. 10. The device according to claim 9> d a d u r c h g e k e n n z e i c h n e t that the slot (38) in the drum wall is the width of the weld seam (15 and 26) are determined. 11 Device according to claims 1 to 9, d a d 4 r c h g e k e n n z e i c h n e t that the rod (16) with the quartz radiator, preferably two Rods (16) offset by 180 ° with quartz radiators on a rotating shaft (39) is arranged and a second shaft (40) with resiliently mounted quartz radiators provided rods (16) is present, with the rotation of the various Waves (39> 40) associated rods (16) these on part of their circumferential movement lie against each other.