DD296450A5 - DEVICE AND METHOD FOR PRODUCING PIPE BODIES - Google Patents

Abstract

A device for producing tubular bodies, in particular for packaging tubes, from a foil strip made of weldable plastic whose longitudinal edges are thermally connected to one another, has a form belt (46) which cooperates with forming rollers (59, 60) and surrounds the foil strip (48) by one Mandrel (45) to form a tubular body, a lower in the mandrel (45) running, driven conveyor belt (20) and an upper driven conveyor belt * between which the longitudinal edges of the film strip (48) are received overlapping each other. The upper conveyor belt (20) is formed as an endless, a heating device, a pressure device and a cooling device unterfahrendes belt and the heater as an inductively acting high frequency heating. In a method that can be carried out with this, the foil strip (48) is formed in its longitudinal direction to form a tube with an overlap formed from the film spacers, and the overlap with its outer and inner tube sides into one of the two transport belts endlessly revolving and driven parallel to one another (20, 33) formed band gap (70), melted therein by the Transportbaendern (20, 33) at least until the formation of liquid-capable phases under pre-solidification of the fluidizable phases and then cooled using pressure. Fig. 1 {manufacture; Pipe body for packaging tubes of films; Film forming around mandrel; melting; pressing; Cooling a weld

Description

-z- 296 450 Apparatus and process for the manufacture of tubular bodies

The invention relates to a device and a method for producing tubular bodies, in particular for packaging tubes

made of a weldable plastic film strip whose longitudinal edges are thermally connected to each other.

From US-PS 3388017 is an apparatus for producing tubular bodies of a thermoplastic strip material

known in which the strip material from below by a smaller width than the strip material having driven

Underlayed conveyor belt and introduced together with him in a split, open-top mold sleeve. Furthermore, two driven conveyor belts are provided, one of which is guided in grooves of a dome and the other so

is arranged, that the overlap point of the pipe strip is clamped by both conveyor belts during the passage through the molded body formed by the mold sleeve pressure.

The heat transfer during seam welding takes place by contact heat, which of heating and downstream heat sinks

is brought on a conveyor belt on the film or derived from this. The disadvantage is in this known

Devices perceived that uncontrollable frictional forces occur in the molding, which often too Relative movements between the conveyor belts and already softened seam and thus from a bad Appearance of the seam lead to non-usable tubular bodies. According to the known embodiment, a conveyor belt interacts with both the welding and the cooling zone. There

the conveyor belt has different heat contents according to the zones, worsens in the case of

Relative movements the quality of welds more clearly than if a first conveyor belt only with the welding zone and

a second would interact with the cooling zone. Incidentally, a one-piece upper conveyor belt is under higher thermal stress than a two-part, which is regarded as a disadvantage with respect to a synchronous operation between upper and lower conveyor belts.

The embodiment of the US-PS 3388017 otherwise adhering deficiencies in connection with in the opinion of the art

one-piece upper conveyor belts adhering to technical restrictions have to two development directions for

Devices for the purpose in question. From CH-PS 614,660 a plant for the production of deformable tubular body of thermoplastic film tape is known,

wherein the film strip may be an at least three-layered metal / plastic composite film, a so-called monofilm.

Similar to the embodiment of US-PS 3388017, the tubular body is in a stationary molding apparatus

consisting of a molded sleeve with inlet funnel and socket and inlet funnel piercing mandrel in grinding

Contact of the film strip formed with the components of the molding device. The tube formed in the molding apparatus

is by means of an upper, driven conveyor belt and a lower in a mandrel freely moving conveyor belt in

Axial direction of the dome moves. The upper driven conveyor belt cooperates with a heating and pressing device,

which heat and compress the overlapping edges of the film while cooling is done directly, i. H. without using one

Cooling belt, takes place. In the case of the production of tubular bodies of composite films, the heating should preferably by high frequency at Monofilms by ultrasound, done. Since a molding apparatus is provided, occur as in the molding apparatus according to the US-PS 3388017 friction forces on Lead relative movements between the seam and the conveyor belts with the known disadvantages. The one-piece upper, only

with the heating and pressing cooperating conveyor belt, reduced due to its relatively uniform

Wärmeinhaltes the disadvantages of the device according to the US-PS 3388017 something, but does not eliminate them. Another development direction representing apparatus for the production of tubular bodies is from the European Patent application no. 0264663 known. The device is fed to a foil strip, the one in at least two Plastic layers embedded aluminum layer includes. In the device, the film strip by means of a Formriemens, which cooperates with guide elements, rolled up to a tube with overlapping ends around a mandrel. The known from the prior art stationary molding devices are here by a running Forming belt on the film during deformation free any movement between the belt and the film and thus

frictionless, replaced.

The overlapping ends reach between a lower, driven on the mandrel, driven conveyor belt and two

subordinate upper, driven conveyor belts, wherein by means of the first conveyor belt the

Welding by heat and pressure and the cooling of the weld by the second downstream conveyor belt

he follows.

The necessary for welding heating of the plastic layers is produced by the fact that the metallic layer

is inductively heated during the compression of the edges by high frequency, the welding heat so directly in the

Foil is created. By using a two-piece upper conveyor belt, the weld can also during the Cooling be formed by the action of external forces without, as in a one-piece, the welding and cooling device

Underlying conveyor belt, the higher thermal load with its known effects in terms of

Synchronous running must be accepted. As a disadvantage, it has been found in this embodiment that closes with their monofilm-the term monofilms

Also multi-layer plastic films in which, for example, a gas-tight plastic layer between two non-gas-tight

Layers z. B. of polyethylene is embedded-not in the required quality can be welded. The required quality

is achieved neither by the heating of the conveyor belts by inductive heating with heat to the monofilm nor the application of ultrasound to heat the film.

Based on this prior art, the inventor has made the task, while avoiding the known Devices adhering disadvantages, a device for producing compressible tubular body of monofilms

create, which works with inductively acting high frequency for the production of welds.

This object is achieved by the subject matter of claim 1. Regarding further features and Embodiments of the invention is made to the subclaims. In contrast to the known devices for welding composite films by means of high frequency, wherein the Heat of fusion predominantly arises in the composite film itself, are in the inventive device the Conveyor belts heated by high frequency, in turn, the heat for melting the plastic to the Deliver plastic film. In this embodiment, it has surprisingly been found that so monofilms weldable

be, with the welds have a very good quality. Furthermore, it was surprising that the thermal load of undisturbed according to the invention, the heating device, printing device and cooling device unterfahrenden conveyor belt is significantly lower than a split conveyor belt, the same operating parameters for the welding of

Composite films is used. Thus, no other means than the inventively proposed for securing the Synchronous running of the two conveyor belts and the belt necessary. In the context of the invention is also a device according to the features of claims 8 to 15, with these is the object

solved, a device known from the European patent application 0264663 as far as and for the inventive use to improve so that using a one-piece upper conveyor belt

Monofilms can be processed to tubular bodies with welds consistently good quality. With the inventive design of the known device can be with high feed rate Produce tubular body from monofilms with welds of very good quality. The covered by this invention process for the production of tubular bodies of monofilm should allow tubular body with

produce the same weld quality and production speed. For this purpose, the film tape (monofilm tape) to

Forming a weld in its longitudinal direction to form a tube with formed from the film edges overlap

and the overlap with its outer and inner tube side to each other endlessly circulating and driven

Ribbon formed formed conveyor belts, melted therein at least until the formation of flowable phases

pressed under Vorerstarrung the flowable phases and then cooled under pressure.

With respect to further features and embodiments of the method, reference is made to the subclaims 17 to 19. With this method, it has now become possible, tubular body of monofilms with the same manufacturing safety and Production speed as tubular body made of composite films. Further advantages, features and details of the invention will become apparent from the following description of a

preferred embodiment and with reference to the drawings. Show it

Fig. 1: An apparatus for producing tubular bodies for packaging tubes in a schematic side view; Fig. 2: a detail of Figure 1 on a larger scale compared to Fig. 1. 3 shows a section through a molded element approximately along the line IH-III in Figure 2;

4 shows the enlarged section through a part of the device for positioning and pre-pressing a plastic film on a dome.

The device according to the invention for producing tubular bodies shown in FIG. 1 consists of a base plate 10, to

a tarpaulin 11 is articulated movable in the vertical direction. The movable linkage via actuators 12, which are arranged between the base plate 10 and the support plate 11. The latter is positioned by means of the actuators 12 in their position vertical and can be fixed.

The schematically illustrated actuators 12 are preferably pneumatically activatable actuators whose

upper ends 13, a piston housing, are respectively secured to the base plate 10, while their lower ends 14, respectively the free end of the piston rods, are engaged with the support plate 11.

The support plate 11 carries at the lower end of its front edge 17 a freely rotatably mounted roller 16 and at a distance above it

equally configured roller 15 whose axial positions are not changeable.

At a distance from the rear edge 18 of the support plate 11, a drive roller 19 is arranged on the base plate 10, whose Diameter d of the sum of the axial distance of the rollers 15 and 16 and half the diameter of these rollers 15 and 16

equivalent.

To the drive roller 19 and the rollers 15,16 runs an endless metallic conveyor belt 20 with an upper run 21 and

a lower run 22, due to the diameter d of the drive roller 19 and dimensioning and positioning of the upper

Roller 15 and the lower roller 16 parallel to each other. The distances of the upper roller 15 and lower roller 16 of the support plate 11 and the distance of the drive roller 19 of the Base plate 10 are dimensioned so that the conveyor belt 20 at a uniform distance from and in front of the surface of the Support plate 11 moves, with the front surface, the surface of the support plate 11 is designated, which is the linkages of the

lower free ends 14 of the actuators 12 bearing surface of the support plate 11 is opposite.

Between upper run 21 and lower run 22 and cooperating with the inside, are on the support plate 11 - in Direction of movement of the conveyor belt 20 after the lower roller 16 - on the support plate 11 one after the other Heating device 23, a pressure device 24 and a cooling device 25 arranged to be movable in the vertical direction and

rail-shaped.

For the purpose of vertical adjustment, the heating device 23 with an actuator 26 z. In the form of a Pneumatic cylinder connected to piston rod. The pneumatic cylinder housing is connected to the support plate 11 and the free end of the Piston rod connected to the heating device 23 so that upon appropriate activation of the actuator 26 a

vertically directed lifting or lowering movement of the heating device 23 can take place.

The heating device 23 includes - extending in its longitudinal direction - preferably an inductively acting High frequency heating, the heat generated in the operating state on the lower run 22 of the conveyor belt 20 and on the

underlying upper strip 34 transmits another metal conveyor belt 33. For a uniform

Heating or heating of the lower run 22 and the upper run 34 is essential that the heating device 23rd

not only for setting z. B. their contact pressure on the inside of the lower run 22 vertically but also in the

Direction of movement, z. B. to the center line, aligned or rectified adjustable, which by changing the Longitudinal position of the heating device 23 to the support plate 11 is effected. The printing device 24 is like the heating device 23 via an actuator 27 in the form of, for example, a pneumatic cylinder

mounted with piston rod on the support plate 11 in the vertical direction adjustable, so regardless of the bearing pressure of the

Aufheizeinrichtung 23 a variable contact pressure of the pressure device 24 to the interior of the lower run 22 to To exert influence on the flow behavior of various plastics. The vertical adjustability of the heating device 23 and printing device 24 serves a total of three purposes. Once can

so that the device can be adjusted to the processing of films of different thickness. Next are about the

Contact pressure and the temperature and the pressing pressure material-specific values adjustable. Furthermore, the vertical serves Adjustability to compensate for thickness variations of plastic films. For the latter purpose are sensors (not shown)

provided, which scan the corresponding values and forward for adjusting the actuators 26,27.

At the lower end of the support plate 11, the cooling device 25 is in sliding engagement with the inside of the lower run 22. In the selected embodiment, the cooling device 25 consists of three cooling blocks 25 _a , in a common Holder are mounted on the support plate 11 in the vertical direction movable limited. Between the holder and the respective, the interior of the lower run 22 opposite side of each Cooling block 25, compression springs 28 are provided which exert a pressing force in the direction of the interior of the lower run 22,

so that for the purpose of uniform heat transfer from the lower run 22 to the cooling device 25 a secure contact is ensured.

Is in the direction of movement χ of the lower run 22 in the cooling device 25, a rising or falling heat extraction desired

so this can be done per cooling block 25, by the installation of compression springs 28 with correspondingly stronger or weaker Federerkräftenbewegt.

To maintain a constant heat capacity, the cooling blocks 25, the cooling device 25 with

a heat-absorbing medium, preferably by means of a water flow passed through the cooling blocks 25, or

Air-cooled. By adjusting the amount of coolant per unit time, the heat absorption or the heat extraction,

be adjusted according to welding material specific requirements.

The printing device 24 is cooled in the manner of the cooling device 25, so that the compression of about a weld

including their pre-solidification before entering the cooling device 25 during operation of the invention

Device can be done under constant temperature. Above the heating device 23, the pressing device 24 and the cooling device 25 is on the support plate 11 at least

a cooled by water cooling rail 29 is arranged, which cooperates with the inside of the upper run 21 and cools so far that he-after his deflection around the rollers 15 and 16- as the lower run 22 with a constantly uniform

Temperature enters the heating device 23. Between the inner sides of the upper strand 21 and lower strand 22 are two acting on the dreams, freely rotating Adjusting rollers 30 and 31 are provided. Between the adjusting roller 31 and the drive roller 19 is a freely rotating Tensioning roller 32, which acts on the outside of the upper run 21. With non-adjustable axial position of the drive roller 19 serve the adjustment rollers 30,31 and the tension roller 32 for a Purpose, when changing the vertical distance H of the roller 16 to the position of the upper tape 34 of the endless Conveyor belt 33 the parallel operation of the upper run 21 on the cooling blocks 29 and the lower run 22 on the Heater 23, the pressure device 24 and the cooling device 25 to make adjustable. In addition to the adjustment of upper run 21 and lower run 22, the rollers 19,31 and 32 serve the setting and Keeping constant the tension of the conveyor belt 20. The adjusting rollers 30 and 31 are by means of roller holders 36 and 37 at the Base plate 10 at the same distance as the rollers 15,16 movably mounted by the base plate 10. Each roll holder 36 and

37 carries at a free end the corresponding adjusting roller 30 and 31, while at the other end it is attached to a fixed anchoring 38,39 of the base plate 10. The roller holders 36, 37 are adjustable and pivotally formed relative to the anchors 38, 39 so that the distance between the latter and the axis of the adjusting rollers 30, 31 is changed and these are movable in a radially variable distance about the anchors.

The tension roller 32 is attached to the base plate 10 by means of a two arms 40,41 existing toggle lever. These Legs 40,41 limit each other a fixed opening angle and are at their intersection to a fixed Anchor 42 rotatably mounted. The one leg 40 carries at its free end the tension roller 32, while the free end

of the leg 41 is connected to a pneumatic or hydraulic actuator 43, so that upon actuation of the

Tension pulley 32 is movable about the anchor 42 for adjusting the tension of the conveyor belt 20. To keep constant

The tape tension is a sensor 44 which receives the voltage of the tape and / or its temperature and the

Regulation corresponding movements of the actuator 43 triggers. The part of the device with which a tubular body is formed comprises, as shown in FIG. 2, 3 a mandrel 45, a circumferential

driven forming belt 46, which carries on its side facing the mandrel 45 a plastic film strip 48, and several in the longitudinal direction of the dome 45 in spaced-apart form elements 47, the forming belt 46 and the

Lay the foil strips 48 around the circumference of the dome 45 and thereby deform elastically. The round in cross-section mandrel 45 is fixedly disposed on the base plate 10 and extends rectified and at a distance

to the heating device 23, printing device 24 and cooling device 25 (FIG. 2). In the top of the dome 45 is a

Longitudinal groove 64 formed in which the upper band 34 of the metallic conveyor belt 33 runs, that at the front end

of the dome 45 slides around a deflection roller 49 and is returned as a lower band 35 in the mandrel 45. According to FIG. 3, the longitudinal groove 64 is provided on the bottom side with an insulation 65 for preventing the dissipation of the heat generated in the upper band run 34. Between the latter and the lower strand 22 of the upper metallic conveyor belt 20, a gap 70 is formed by - in Fig. 4 seen - overlapping edges of the film strip 48 to form a longitudinally extending

Welded seam first, then pressed and then cooled.

According to Figure 1, the conveyor belt 33 runs around a fixedly arranged on the base plate 10 drive roller 50, an inside touching freely rotatable tension roller 51 and arranged on its outside adjustment roller 52, which introduces the upper tape 34 into the longitudinal groove 64 of the dome 45 and in cooperation with the guide roller 49 ensures horizontal synchronization to the deepest of the longitudinal or guide groove 64. In the strip running direction, the deflecting roller 49, which is not adjustable in its axial position, and a further adjusting roller 53 follow.

The tension roller 51 and the adjusting rollers 52 and 53 are - as the rollers 30,31, and 32 - provided on the base plate 10, wherein the tension roller 51 also via a temperature and / or tape tension receiving sensor 44th and an actuator 55, the belt tension constant holds. This makes it possible, when using different mandrel diameter, the distance J between mandrel longitudinal axis Unt and lower strand 22 while maintaining the parallel operation of the lower strand 22 to the upper belt 34 and the lower belt 35 to the upper belt 34.

For heating the conveyor belt 33 to at least the inlet temperature of the lower strand 22 in the heating device 23, a resistance heater 56 is preferably provided in the form of a high frequency coil before the adjustment roller 52.

The aforementioned, the mandrel 45 receiving mold element 47 consists according to Figure 3 of a support block 57 which is fixed with one side 58 on the base plate In the support block 57, a forming roller 59 is disposed below the dome 45, which rotates about a horizontal axis, while two each arranged laterally to the mandrel 45 form rollers 60 and 61 rotate about vertical axes, which are eccentrically adjustable for fine adjustment of the size of the overlap region of the film edges ,

Fig. 1 shows that a plurality of the mold elements 47 - optionally connected in common carrier block 57 - are connected in series. From the first mold element 47 proceeding in the running direction of the lower drum 22 up to the mold element 47, the edges of a film strip 48 positioned in overlap on the upper belt run 34 of the conveyor belt 33, the distances of the horizontal and vertical axes of rotation to the center of the dome 45 decrease so that the concave-shaped running surfaces 61 of the shaping rollers 59, 60 between them and the mandrel 45 running the shaping belt 46 with the film strips 48 resting on them deflect longitudinally about the mandrel 45. The width of the forming belt 46 is less than that of the overlying film strip 48.

An application of the film strip 48 to the dome 45 is only to the extent that overlap the edges of the film strip 48 between the lower run 22 of the conveyor belt 20 and the upper belt 34 of the conveyor belt 33 and are held by the edges of the belt 46 in this position, the inner surface of the tube tube thus formed but to avoid frictional forces on the outer surface of the dome 45 is not applied.

As a result, in the case of plastic monofilms, laminates made of plastic films of various chemical composition-a tearing off of the melted-up in the heating device 23 overlap of the adjacent unfused material of the pipe wall is prevented, which ensures a consistently dense and tear-free at its outer edges weld. Once the weld by heat removal has a predetermined mechanical strength and dimensional stability, take the center distances of the form rollers 59,60 from the center of the dome 45 from again, so that the belt 46 opens and with tube after release of the tube from the lower strand 22 and upper strip 34 can run substantially in the longitudinal direction of the mandrel 45.

1, the endless, preferably made of easily deformable fiber-reinforced plastic existing form of belt 46 is driven by a drive roller 62, passed over a belt tensioning device 63 and further deflection rollers.

The drive roller 62, the belt tensioning device 63 and the deflection rollers are arranged at such a measured distance to the base plate 10, that the center line of the belt 46 coincides with the vertical center line of the dome 45, so that the edges of the belt 46 when passing through the mold elements 47th - Where appropriate, supported by an eccentric adjustment of the form rollers 60- always opposite each other in a substantially horizontal plane, whereby a precisely sized in its width overlap area is ensured.

For the production of a perfect weld on tubular bodies made of monoplastic films, it has in particular for their surface formation and to avoid squeezing molten plastic along the inner and outer edges of the overlap region and to avoid stresses and strains in and at the edges of the weld than proven advantageous to drive the conveyor belts 20 and 33 and the belt 46 in the same rotational speed, so no relative movement between lower run 22 and overlapping edges of the film strip 48 on the one hand, the overlapping edges of the film strip 48 and the upper tape 34 on the other hand and beyond between the form of belt 46th and the film strip 48 lying thereon, whereby the overlapping film edges between the running conveyor belts 20 and 33 are melted, pressed, pre-solidified and cooled in the rest position.

For this purpose, the drive rollers 19,50 and 62 are controlled in their drive speed matched, and the belt tensioner 63 and the tension rollers 32 and 51 are activated in their set position so that the conveyor belts 20,33 and the form of belt 46 are under constant predetermined voltage ,

With the device according to the invention, a tubular body formed from single or multilayer plastic film without a metallic barrier layer is produced as follows.

At a contact point A of the film strip 48 runs flat on the flat-running also form belt 46 and is - lying flat-form belt 46 to the mold elements 47 worn. Above the film strip 48 is the mandrel 45. In the form of elements 47 of the form of belt 46 with film strips 48 over the forming rollers 59,60 cross-sectionally substantially circular with decreasing diameter around the mandrel 45 is formed until the edges of the film strip 48 one in his Size predetermined overlap area have formed. The width of the forming belt 46 is such that after forming the overlap region, the opposed edges of the forming belt 46 do not overlap the overlapping area for subsequent processing but form a gap therebetween in the longitudinal direction of the tube tube in which the overlap area is exposed.

To fine-tune the design of the overlap region, the form rollers 60 can be adjusted thanks to their eccentric so that the free edges of the belt 46 move the edges of the film strip 48 more or less against each other, creating an identifiable in its width overlap area. After formation of this overlap region, this is the upper strip 34, which is guided on the surface of the dome 45 in a longitudinal groove 64.

The forming of the film strip 48 and the belt 46 is such that only the overlap region on the upper Tape 34 rests, but otherwise to avoid friction between the stationary mandrel 45 and transported Foil strip 48 no contact between foil strip 48 and Dom 45 takes place. To maintain a certain operating temperature of the mandrel 45 is disposed with a channel 69 disposed in its interior

provided, which is traversed by a cooling medium. Similarly, inside a louver of a in

Longitudinal direction of the dome 45 running bore 67 attached, from the in the region of the printing device 24 in the direction of the Guide roller 49 go out to the end of the dome 45 radial bores 68, which open out at the periphery of the dome 45 and air

for cooling purposes, reducing friction and calibrating the pipe diameter into the space between the mandrel surface and inner wall of the pipe.

After formation of the overlap region, the latter enters between the conveyor belts 20, 33. The lower run 22 of the conveyor belt 20 is in contact with the inside of the heating device 23, which the

Metallic conveyor belts 20 and 33 by high frequency induction heats up to a temperature sufficient to

To bring plastic to a temperature necessary for the welding under pressure. Upon completion of the heating, the molten overlap area undoes the printing device 24 which is in contact with the printer Inside the Untertrums 22 acts pressed the overlap area and at the same time cools so that he in his Design vorerstarrt in the subsequent cooling device 25 enters. In this, the overlap area is over the Untertrum 22 withdrawn the necessary for its mechanical strength residual heat. After the overlapping area has reached a certain mechanical strength, the shaping belt 46 opens thereby,

that the center distances of the forming rollers 59,60 increase to the circumference of the dome 45, so that the welded tube from the tube

Dorn 45 can run freely for further processing. For the production of stress and crack-free welds for tubular body made of plastic films is essential that no Relative movements during the formation process of the weld between the surfaces of the overlap region

the belt runs cooperating with the surfaces and between film strips 48 and forming belt 46 takes place. For this purpose, the metallic conveyor belts 20,33 and the forming belt 46 are driven at the same speed and held under constant constant voltage to heat-related expansions and thus individual

Turn off speed changes.

Claims (19)

1. A device for the production of tubular bodies, in particular for packaging tubes made of a weldable plastic film strip whose longitudinal edges are thermally interconnected, with a cooperating with form rollers form belt which forms the film strip around a mandrel to a tubular body, a lower mandrel current, driven conveyor belt and an upper driven conveyor belt, between which the longitudinal edges of the film strip are received overlapping each other, at least one acting on an upper conveyor belt heater, printing device and cooling device. 2. Apparatus according to claim 1, characterized in that the upper conveyor belt is formed as an endless, the heating device, printing device and cooling device unterfahrendes band and the heater is designed as an inductively acting high frequency heating. 3. Apparatus according to claim 1 or 2, characterized in that the heating device to the direction of the conveyor belt (20) is adjustable in the vertical direction, wherein optionally the vertical adjustment by means of pneumatically or hydraulically activatable actuators (12). 4. Device according to one of claims 1 to 3, characterized in that the longitudinal axis of the rail-shaped heating device (23) to the longitudinal axis of the conveyor belt (20) is adjustable, and / or that the pressure device (24) to the running direction of the conveyor belt (20). is adjustable in the vertical direction, wherein optionally the pressure device (24) is rail-shaped. 5. Device according to one of claims 1 to 4, characterized in that the pressure device (25) by means of a heat-absorbing medium, preferably water, is cooled, and / or that the cooling device (25) by means of springs (28) under bias with the Transport belt (20) is engaged. 6. Device according to one of claims 1 to 5, characterized in that the cooling device (25) consists of several in the direction of the conveyor belt (20) successively arranged cooling blocks (25 _a ), the latter optionally under different spring bias with the conveyor belt (20). are engaged and / or that the conveyor belt (20) with one or more of the cooling blocks (25 _a ) downstream cooling rail / n (29) is engaged. 7. Device according to one of claims 1 to 6, characterized in that the heating device (23), printing device (24) and cooling device (25) and optionally the cooling rails (29) on a relative to the mandrel (45) vertically movable support plate (11) are arranged. 8. The device according to at least one of claims 1 to 7, characterized in that the upper one-piece conveyor belt and the lower one-piece conveyor belt with tape tensioning and this are automatically adjusting to predetermined values belt tensioning devices are engaged. 9. Apparatus according to claim 1 or 8, characterized in that the belt tensioning device of the upper conveyor belt (20) from an adjustably mounted, with the inside of its upper strand engaged adjusting roller (31) about an anchorage (42) pivotally mounted toggle lever (40 , 41) having a tensioning roller (32) which is rotatably arranged at a first free end and engages with the outside of the upper run (21) of the conveyor belt and an actuator (43) arranged at the second free end of the toggle lever (40, 41). consists. 10. Apparatus according to claim 8 or 9, characterized in that the toggle lever (40,41) for pivotal movement of the tensioning roller (32) by means of a pneumatically or hydraulically activatable actuator (43) is connected, optionally in the region of the tension roller (32) the voltage of the conveyor belt (20) determining, the actuator (43) controlling the sensor (44) is provided. 11. Device according to one of claims 8 to 10, characterized in that the upper strip run (34) of the lower conveyor belt (33) on its inside with an adjusting roller (51) and on its outside with an adjusting roller (52) is engaged, wherein the adjusting roller (51) is pivotally supported about an anchor, and / or that the toggle lever for pivotal movement the adjusting roller (51) by means of a pneumatically or hydraulically activatable actuator (55) is movable, optionally in the range of the adjusting roller (51) a the tension of the conveyor belt (33) and determining the toggle lever on the actuator (55) controlling sensor (44 _a ) is provided. 12. The device according to at least one of claims 8 to 11, characterized in that the conveyor belt (20) arranged on one of the base plate (10) drive roller (19) and two on the support plate (11), optionally with the support plate (11 ) in the vertical direction adjustable guide rollers (15,16) is guided, wherein the diameter (d) of the drive roller (19) for forming the parallel run of the upper run (21) and the lower run (22) of the conveyor belt (20) the center distance of the pulleys ( 15,16) plus the sum whose half diameter corresponds. 13. The device according to at least one of the preceding claims, characterized in that between the cooling device (25) and the drive roller (19) on the inside of the lower run (22) of the conveyor belt (20) acting adjusting roller is provided, and / or that the lower endless conveyor belt (33) about an on the base plate (10) arranged drive roller (50) on the base plate (10) arranged adjustable guide rollers (53,52) on the surface of the dome (45) in a groove (64) whose Floor is optionally provided with insulation, at the free end of the mandrel (45) deflected around a guide roller (49) and from there in the interior of the dome (45) in ener recess (66) is guided. 14. The device according to at least one of the preceding claims, characterized in that on the base plate (10) arranged support blocks (57) at least about a horizontally extending axis rotatably mounted form roller (59) and at least one pair of opposing, each about vertical axes having rotatably mounted form rollers (60), wherein the peripheral surfaces of the forming rollers (59,60) are concave. 15. The device according to at least one of claims 1 to 14, characterized in that the endless circumferential forming belt (46) cooperates with a belt tensioning device (63) for keeping constant a constant predetermined belt tension and synchronously driven in its rotational speed to the rotational speed of the conveyor belts, optionally the latter and the forming belt (46) rotate at the same speed. 16. A method for producing tubular bodies, in particular for packaging tubes, made of a weldable plastic film strip, in particular with use of a device according to at least one of the preceding claims, wherein the film strip to form a weld in its longitudinal direction to a tube with one of the Formed overlap formed with their outer and inner tube side in a formed of two parallel endless circulation and driven conveyor belts band gap, melted by the conveyor belts at least until the formation of flowable phases melted under pre-solidification of the flowable phases and then using Pressure is cooled. 17. The method according to claim 16, characterized in that the metallic conveyor belts are heated by means of a high-frequency induction heating, and / or that the flowable phases are brought to pre-solidification by cooling a co-operating with a conveyor belt pressure device. 18. The method according to claim 16 or 17, characterized in that is removed by a cooperating with a conveyor cooling device of the overlap under pressure, the amount of residual heat necessary for full solidification, wherein optionally the residual heat amount is under adjustable pressure load. 19. The method according to any one of claims 16 to 18, characterized in that in the region of the printing device, the inner tube wall is cooled, and / or that in the region of the cooling device, the inner tube wall is cooled, and / or that in the region of the printing device and cooling device inner pipe wall is cooled. For this 2 pages drawings