Form, fill and seal apparatus

Abstract: Apparatus (1) for forming bags from a web (B) of synthetic film, filling them with a product and sealing them, comprising forming means (8, 33) for transforming a fed flat web of heat sealable material into a tubular form with overlapping margins, first heat sealing means (14) for forming a longitudinal sealing seam in the formed tube at the overlapping margins by heat sealing and second heat sealing means (15) for forming transverse sealing in the formed tube by heat sealing, as well as means (16, 19) for supplying a strip (S) of the same material up to and parallel to the tubularly formed web at a location upstream from the second heat sealing means which form the transverse sealing seam and downstream from the location where the film web is transformed to a tube.

Description: The invention relates to a form, fill and seal apparatus, in particular to an apparatus for forming bags from a web of material, filling them with a product and subsequently sealing the bags, the filling taking place in a vertical way. Apparatuses of this kind are very well known and are particularly used for packing products in plastic bags. A rolled up web of, for example, polyethylene or polypropylene film is rolled off from a roll and guided over a forming shoulder with a forming tube, around which the film is wrapped, forming a tube which in the course of the further process moves downward over and from the forming tube. The forming shoulder is open at the top and and forms there the beginning of a filling sleeve for products which are to be put into the bags which extends vertically through the forming tube. After the film web has been formed into a tube a continous longitudinal seam is formed at the location of the margins of the web which overlap each other, by means of a heat sealing rod placed against that. Two double transversely disposed heat sealing rods are located on either side of the downwardly extending tube beneath the heat sealing rod, which are periodically moved towards each other in order to clamp the tube film between themselves and then to be activated to form a seal, after which a certain quantity of the product to be packed is dispensed and will fall downward through the forming shoulder and the forming tube. At the same time the tube is pulled down over the rise of one bag by the heat sealing rods which still clamp the film tube. Then the double heat sealing rods are again moved upwards over the rise of a bag and are brought into heat sealing engagement with the tube again so as to form at the same time the upper transverse seal of the bag Just filled and the lower seal seam of the bag still to be filled. At the same time also a cutting means arranged between these rods is also activated, so that each time a filled bag provided with a longitudinal seam, an lower seam and an upper seam is divided from the following tube. For several years now it has become clear that the use of synthetic materials for packaging can, from an environmental point of view, be very disadvantageous, in particular because used packages can form a waste element which is difficult to recycle and to reuse. For these reasons the packaging industry has been searching assiduously for alternatives to synthetic materials. Paper can form an important alternative. However, paper is a packaging material which was abandoned in the past because it was not able to answer the demands made with regard to packaging material in modern times. These demands concerned the processing speed, the reliability of closures and such like. A form-fill-sealing assembly for producing filled paper bags, as described in the preamble of claim 1, is known from US-A-3.557.525. A first alternative whereby paper was used consisted of using paper with a coating of heat sealable material. Although in this way the synthetic part in the packaging was reduced considerably, the waste did still contain a certain quantity of synthetic material formed by the coating. Besides, having to apply a coating to the web of paper increased the costs. The invention aims to improve on the circumstances described above and provides to this end, an apparatus as described in claim 1. With the apparatus according to the invention bags can therefore be made of non-heat sealable material such as paper, in a reliable manner, without a neat sealable coating being necessary. With the apparatus according to the invention bags can be made from a material which comes from the basic industry, for example the paper industry. Then it is not necessary to call in other supply companies. This hot melt adhesive has a very short "open period", in other words it is processable and active at 180° C but already hardened and deactivated at 160°C. This hot melt adhesive will have therefore lost its effect when the material web moves over the forming means, so that the material web when moving over the forming shoulder will not be restrained by interaction between the adhesive surfaces and the surface of the forming shoulder. The closing means are here realized as heating rods which heat the hot melt adhesive to a temperature at which this adhesive is active again. By making use of a hot melt adhesive instead of the more conventional kinds of adhesive for paper for example, as little time as possible need be lost when deactivating the adhesive. According to a preferred embodiment of the apparatus according to the invention cooling means are placed after the first and second adhesive application means and before the forming means for cooling the hot melt adhesive strips just applied in an accelerated way to a temperature at which the hot melt adhesive is no longer active. In this way the apparatus can be kept very compact and the process can moreover take place rapidly. Using dispersion adhesives would soon take up too much time. Preferably the apparatus according to the invention comprises a frame on which the roll holder and the previously mentioned, parts of the apparatus which operate downstream of the roll holder are arranged. The frame is preferably movable. It is observed that a form, fill and seal machine is known from the Swiss patent specification 248.124, whereby (filled) bags are made from a web of paper. The known apparatus is, however, not provided with adhesive application means, so that it can be assumed that the delivered roll of paper web has already been provided with adhesive strips applied at the correct place, which would result in the roll of paper web not having a uniform thickness across the width. It is further observed that a method and a rather complex apparatus for continuously filling tampon bags, is known from a Dutch patent application 75.13157, whereby a web of flexible, liquid permeable sheath, probably cellulose material, is provided with transverse strips of adhesive after having been rolled off a roll and subsequently guided over a heated drying drum to dry the adhesive strips. Then the web is folded into a tube and a longitudinal strip of hot melt adhesive is subsequently applied, the tube is sealed longitudinally and then pressed down on site and cooled. To conclude, the bags are filled horizontally and then transversely sealed, by heating. The invention will now be described on the basis of exemplary embodiments of the apparatus of the invention shown in the drawings. In the drawings: fig. 1 shows a side view of an exemplary embodiment of an apparatus to which the application also refers; fig. 2 shows a top view of the apparatus of fig. 1; and fig. 3 shows an end view of the apparatus of fig. 1. The form, fill and seal machine 101 in figures 1, 2, and 3 comprises a frame 102 which can be placed on a fixed base by means of adjustable legs 104. An electric driving unit 126, a housing 127, a control cabinet 103 and a roll holder 105 are placed on the frame 102. The roll holder 105 comprises a post 128, on the upper end of which a transverse shaft 106 is rotatably attached. This transverse shaft 106 is free at its other end, so that a roll of paper 107 can easily be put thereon. On the righthand side (figure 1) of the housing 127 outriggers 110 are hingedly and resiliently attached on either side thereof, between which compensation rolls 109 are arranged. On its upper surface the housing 127 forms a guiding table 129 over which a paper web K, originating from the roll 107, can be supported and guided. On either side of the guiding surface 129 there are guiding rails 111, along which a transversely placed supporting beam 119 can be adjusted in transport direction J of the paper web K. The supporting beam 119 supports an adhesive application head 117. The adhesive application head 117 is movable back and forth in transverse direction L for applying an adhesive transverse strip by means of a piston-cylinder assembly accomodated in the supporting beam 119 and is connected to the adhesive container 116 by means of a flexible line 121. This adhesive container 116 is provided with heating means for keeping the adhesive liquefied and with pumping means (not shown) for feeding the hot melt adhesive through the line 121 to the adhesive application head 117.The adhesive container 116 is accomodated in the housing 127. A second adhesive application head 118 is arranged in a manner not specifically shown upstream from the adhesive application head 117. The adhesive application head 118 is intended for applying a longitudinal adhesive strip to the paper web K, and is for that purpose connected by means of line 122 to the adhesive container 116. By means of suitable pumping means (not shown) hot melt adhesive from the container 116 is fed through the line 122 to the adhesive application head 118. The adhesive application head 118 can be adjusted in a transverse direction to be set in relation to the longitudinal edge of the paper web K. Further upstream from the adhesive application heads 117 and 118 follower rolls 112 are supported with their ends in the guiding rails 111, the follower rolls 112 being located above the compensation rolls 109. At the downstream side of the adhesive application heads 117 and 118 a removably arranged cooling station 130 is located, which takes care of the cooling of the hot melt adhesive just applied by the adhesive application heads 117 and 118 to the paper web K. The cooling station 130 can be realized in any suitable way. The cooling station 130 can, for example, comprise one or more air blowers, which are directed downward, to cool the adhesive strips of hot melt adhesive applied to the paper web upstream from there. As a matter of course, means are present for delivering cooled air to the air blowers. Downstrean from the cooling station 130 a pair of follower rolls 133 is placed extending between the rails 111, where the direction of the web K is changed to move upward on the combined forming shoulder-filling funnel 108 placed downstream from there. The combined forming shoulder-filling funnel 108 comprises a filling funnel 135, a chute sleeve/forming tube 138 and a forming shoulder 136. The filling funnel 135 is attached by means of bolts 139 to a supporting frame 134, which itself is attached to the rails 111. The filling funnel 135 merges at its lower end in the chute sleeve/forming tube 138 which extends downward through the forming shoulder 136. The forming shoulder 136 is provided with the supporting plate 137 which is itself attached by means of bolts 139 to the support frame 134. The forming shoulder 136 has a conventional form, such that the web K is guided over the upwardly inclined surfaces thereof to within a central vertical passage whilst both side edges are brought into an overlapping position with one another at the side of the forming shoulder 136, facing away from the side at which the web approaches. Thus a downward directed tube is formed, which is not yet sealed with a longitudinal sealing seam, which can move downward in the annular space formed by the inner surfaces of the forming shoulder and the outer surface of the forming tube 138. The forming shoulder has a sharp upper edge to prevent the paper web from creasing locally when it is turned. A transverse rod 131 is mounted to an outrigger 113 to move back and forth in the N directions, the outrigger being mounted to the housing 127. A heated longitudinal seam forming rod 114 is perpendicularly arranged on this transverse rod 131 which can be moved to the surface of the forming tube 138 and away from it again together with the transverse rod 131. The rod 114 is of a length minimally equal to the bag height. Beneath the forming tube 138 an outrigger 132 is mounted to the housing 127 to move back and forth in the O directions. Two transversely placed support rods 125 are mounted on the outrigger 132 which are movable towards and away from each other in the M directions. On their surfaces facing each other the transverse rods 125 carry heated transverse seam forming double rods 115. A cutting means (not shown) is located between each of the double rods 115. The space in which the sealing seam forming rods are arranged and where they move is screened off by means of a movable, transparent panel 120. All movable parts of the apparatus 101 can be operated pneumatically. The operation of the apparatus as shown in the figures 1, 2 and 3 is as follows. A roll of paper web 107 is put on the shaft 106 of the roll holder 105. The paper web K is manually rolled off over a certain length and fed about the compensation rolls 109 and the follower rolls 112, as can be seen in figure 1, and then laid over the guiding table 129, laid about the forming shoulder 108 and fed about the forming tube 112 so that the paper web acquires a tubular form, all this until the then tubular paper web extends up to below the working area of the transverse seam forming rods 115. A delivery apparatus for products to be packed in bags, which is adjusted for delivering suitable doses, is placed above the forming shoulder/filling funnel 108. The apparatus 101 is then put into working order by allowing it to operate for a while without being fed with products. In addition, the transverse seam forming rods 115 are operated so as to clamp the tube paper K in between themselves and to pull it downward over a distance equal to the height of the bag to be formed. During this operation, which in the following will be called the stroke period, the adhesive application head 118 will be operated. Because the transverse seam forming rods 115 tightly clamp the paper web, the paper web K is pulled and will be rolled off and will move along in the direction of arrow J. Thus the paper web K will slide past and below the adhesive application head 118 so that when the adhesive application head 118 is operated a longitudinal adhesive strip is formed. Only very little adhesive is used when applying the longitudinal adhesive strip. This takes place by means of an adhesive applicator tube which is arranged at an angle and is rotated around a vertical shaft. A large part of the adhesive strip will actually be free of adhesive due to the blobs (also called 'whirls'). This is on the one hand an advantage in view of later waste processing, while on the other hand the adhesive will be able cool off more quickly. To give an idea: the applied adhesive thread can have a thickness of 0.1 mm. and the threads can have a centre-to-centre distance of 1 mm. Of the adhesive strip surface 10% is then covered with adhesive. In order to change the width of the adhesive strip the adhesive application head 118 is also arranged to be adjustable for height in relation to the guiding surface 129. When the transverse seam forming rods 115 arrive at the lower end of a vertical stroke the stroke period ends and the rods 115 are moved away from each other so that the paper tube is no longer clamped. The paper web K will then come to a standstill. In the period which elapses until the transverse seam forming rods have returned to their highest position and are operated once more to clamp the paper tube K between themselves and to lead it downward, which period is called here the intervening period, the transverse rod 131 is moved towards the forming tube 138 in the N direction until the longitudinal seam forming rod 114 presses the paper tube against the forming tube 138. The paper web K is guided in such a way about the forming shoulder 108 and the forming tube 138, that in the area of contact with the longitudinal seam forming rod 114 an overlap area is located, where the longitudinal margins of the paper web K are placed over each other. When the apparatus 101 is ready for operation, the outer one of these longitudinal margins will be provided with the longitudinal adhesive strip on its surface facing the other longitudinal margin. In the intervening period the adhesive application head 117 is also operated, which can spout blobs of adhesive thread onto the paper web K in the same manner as the adhesive application head 118. Meanwhile the adhesive application head 117 is moved in transverse direction L by operating the cylinder-piston assembly incorporated in the supporting rod 119. In order to adjust the width of the transverse adhesive strip the adhesive application head 117 and the supporting rod 119 are adjustable in height. The length of the tranverse adhesive strip can herewith be restricted to approximately a half of the web width. Thus more adhesive can be saved. When the apparatus 101 has been in operation so long that also at the height of the transverse seam forming rods 115 the paper web K is provided with a transverse adhesive strip, the position of the outrigger 132 is adjusted until the transverse seam forming rods 115 are exactly located at the height of the transverse adhesive strip. Then the apparatus 101 and the product delivery apparatus - not shown - are brought into action. A start is made with the stroke period in which the transverse seam forming rods 115 are moved towards each other to clamp the paper tube K at the location of the transverse adhesive strip. At the same time the heating elements in the transverse seam forming rods 115 are operated so that the hot melt adhesive in the transverse adhesive strip is activated. Whilst the outrigger 132 is being moved downward in the direction O, and with it the transverse seam forming rods and the paper tube K, a command is given by suitable means to the delivery apparatus to release a measured quantity of products, this measured quantity falling into the filling funnel 135 and through the forming tube 138 into the paper tube B, until this quantity of products is restrained at the lower end of the paper tube K which is closed by the transverse seam forming rods. Because the transverse seam forming rods 115 are each made up of two heated rods placed above one another, an upper seam of the lowest, previous bag and a bottom seam of the subsequent bag are formed simultaneously. Between these double heated rods a knife (not shown) is arranged, which is operated when the transverse seam forming rods 115 have arrived at the end of the descending stroke. At the end of each stroke a filled, cut off bag will therefore be delivered. As has already been mentioned above, the paper web K is only moved during the descending stroke of the transverse seam forming rods 115 and at the same time the adhesive application head 118 is operated to form a longitudinal adhesive strip on one edge of the paper web K. During operation of the machine the vertical stroke can be continuously adjusted by a hand wheel 123. The compensation- and follower rolls 109 and 112 ensure that the film web K remains under tension. During the intervening period the adhesive application head 117 is operated to form a transverse adhesive strip on the paper web K and at the same time the longitudinal seam forming rod 114 is pressed against the overlap area of the paper tube K so that this overlap area is pressed between the heated longitudinal seam forming rod 114 and the forming tube 138. The hot melt adhesive in the longitudunal adhesive strip is then activated so that the paper tube is provided with a longitudinal seam. A continuous longitudinal seam is formed. When the transverse adhesive strip is finished and the longitudinal seam of the paper web K is formed, the adhesive application head 117 is led back to its starting position and the transverse rod 131 and with it the longitudinal seam forming rod 114 is moved away from the forming tube in the N direction, whilst at the same time the transverse seam forming rods 115 are moved towards each other in the M direction in order to allow the stroke period to restart. In this way paper bags filled with a measured out quantity of product are delivered by the apparatus 101, on the lefthand side thereof, the paper bags being sealed by means of a bottom seam, a top seam and a longitudinal seam, whereby only a minimal quantity of adhesive has been used for these seams. By using a hot melt adhesive with a very short "open period", for example a hot melt adhesive which is processable at a temperature of 180° C and hardens, i.e. is deactivated at 160° C, quick production is possible. A production speed of 60 bags per minute is easily attainable. In order to be able to place the adhesive application heads 117 and 118 very close to the forming shoulder 108 or to increase the production speed, placing a cooling unit 130 between the adhesive application heads 117 and 118 and the forming shoulder 111 can be considered. In this way the applied hot melt adhesive can be cooled quickly to below hardening temperature, so that even in the case of a very compact embodiment of the apparatus or a high production speed it still is ensured that the hot melt adhesive is deactivated when the paper web K arrives at the forming shoulder 111. Alternatively transverse and longitudinal cooling strips can be incorporated in the guiding surface 129 which cool the paper web K on the underside thereof at the location of the formed adhesive strips. The way in which the tube is pulled along can also differ; for example by means of friction belts placed on either side of the vertically hanging tube and beneath the transverse seam forming rods. In this way the transverse seam forming rods remain in place in a vertical direction. It is clear that by means of the apparatus according to the invention a product can be packed in a very efficient way with the help of materials which will form as small possible a burden from the viewpoint of waste processing. In this way a large step has been taken in the making of environment-friendly packages. If, however, for whatever reason, one should wish to make bags from a synthetic material, then making bags from non-heat sealable material is made possible too with the apparatus according to the invention. Materials such as nylon and polyester can then also be used for making bags, without having to apply a coating of another heat sealable material on the material web. This would otherwise seriously complicate the recycling of the bag material.

Claims: Apparatus for forming bags from a web of non-heat sealable material, in particular paper, filling them with a product and consequently sealing them, comprising a holder for a roll of web of material, adhesive means for applying an adhesive to the material web, forming means, with which the material web can be transformed into a material tube extending in a vertical direction, said forming means including a forming shoulder and a forming tube, supply means for supplying the product to be packed into the tubular material web and first and second sealing means for longitudinally sealing and at regular distances transversely sealing the material tube, respectively, and cutting means for dividing the tube at the location of the transverse closures into separate bags, wherein the adhesive means comprise a first adhesive application means for applying at least one longitudinal adhesive strip to the material web and a second adhesive application means for applying a transverse adhesive strip to the material web, both being located ahead of the forming means and after the roll holder, characterized by guide and support means (129) for supporting and guiding the material web while passing below the first and second adhesive application means (117, 118), wherein the first and second adhesive application means are spaced above the guide and support means and are adapted for feeding and applying a strip of hot melt adhesive onto the material web, and wherein the first sealing means (114) for longitudinally sealing the material tube comprises a sealing bar (114) and an oppositely located outer surface of the forming tube (138) for clamping the longitudinal edges of the web therebetween. Apparatus according to claim 1, in which downstream from the first and second adhesive application means (117, 118) and upstream from the forming means (108) cooling means (130) are placed for cooling the hot melt adhesive strips just applied in an accelerated way to a temperature at which the hot melt adhesive is no longer active. Apparatus according to claim 1 or 2, in which the apparatus comprises a frame (102) on which the roll holder (105) and the previously mentioned operating parts of the apparatus downstream from the roll holder are arranged.

Inventors: HACHMANG HENDRICUS CORNELUS NI, HACHMANG, HENDRICUS CORNELUS NICOLAAS
Applicants: HACHMANG MACHINES BV, HACHMANG MACHINES B.V.
Application year: 1993
Main classification: B65B9
IPC codes: B65B61, B65B9