FR2596732A1 - Valve element intended for filling bags - Google Patents

Abstract

A valve element is described which comprises an inlet tubular sleeve 2 engaged in a bag 3 via an opening located at one of its corners. The sleeve 3 is formed from a first, paper sheet 8 to which a second, plastic sheet 9, covering the sleeve 2 on its inside, is adhesively bonded. The presence of the plastic sheet 9 prevents any accidental closure of the sleeve 2 as a consequence of adhesive bonding due to the adhesive used during the manufacture of the bag 3. The plastic sheet 9 may be replaced by a plastic tubular element 12. … …

Description

The present invention relates to a valve for

  filling bags. In particular, the valve according to the invention is of the type which is normally applied to bags for industrial use, commonly called "valve bags".

  We know that the valve bags are arranged and

  structured so that they can present themselves as best as possible to allow the automatic conditioning of the material intended to be introduced therein.

  For this purpose each of these bags is closed, before filling, either at the bottom or at the top, and is provided with a valve intended to allow its filling. In more detail, it can be noted that during the filling of the bag the valve lends itself to the use of a nozzle of

  distribution, part of an automatic bagging machine, from which the material to be bagged comes out.

  Currently there are basically two types

different from valves.

  The first type of valve essentially consists of a tubular sleeve obtained by gluing. a sheet of paper at the top or bottom of the bags before they are closed. When closing the top or bottom of the bags the sheet is folded together with the parts intended to form the closure itself, thus taking a substantially tubular structure in the form of a sleeve. 25 It is also provided that a portion of the sleeve extends inside the bag, in order to limit, when the bag is filled, material outflows through the valve if the latter is located at the bottom of the bag. In this situation, in fact, the action exerted by the weight of the material on the sleeve automatically causes the closure of

the valve by crushing.

  Another type of valve also known is obtained - 2 essentially identical to that previously described, with the only difference that an auxiliary sheet of low density polyethylene is arranged between the sleeve and the corresponding portion of the bag to which the sleeve is engaged. , this sheet extending inward of the bag beyond the end

of the sleeve.

  The function of the auxiliary sheet is essentially that of enhancing the effect. of said closure of the 10 valve when the bag is filled, thanks to the stiffness more

  reduced low density polyethylene compared to the paper from which the sleeve is made.

  After the above summary description, we can

  note that known valves present problems during the bag filling step.

  This is due to the fact that during the manufacture of the bags it can easily happen that the inner surface of a sleeve is stained with glue, when the sleeve is glued to the bag or when closing

  from the bag. In this case there is reciprocal bonding of the interior surfaces of the sleeve.

  One can well imagine that when a bag arrives at the bagging machine under the conditions specified above, the dispensing nozzle of the bagging machine cannot be properly engaged in the valve, which causes the fall outside the bag. bag of material delivered by it.

  This situation, which obviously leads to wastage,

  material and production dead times, these times being necessary for cleaning the machines and the areas on which the spilled material has spread,

  has very negative aspects when bagging corrosive, toxic and similar products.

  Another drawback of the known valves is that they are not always in a condition to prevent as best as possible the exit of the material from the corresponding bags. Indeed, especially if the bags undergo di5 towards reversals, there is always dispersions of material which can cause problems especially when

  the bags contain corrosive or toxic materials.

  In this situation, the object of the present invention is to eliminate the drawbacks of the known art, using both a valve intended for filling bags which offers higher reliability of use.

  than that offered by known type valves.

  This object and others which will emerge more clearly from the description which follows, are essentially achieved by a valve intended for filling bags,

  comprising a tubular inlet sleeve engaged to one of said bags through an opening formed in correspondence with an angle of the bag, characterized in that said inlet sleeve has a portion of its inner surface 20 coated with plastic material, which extends, essentially along a plane perpendicular to the main development of said bag, over at least half of the span

due to said inlet sleeve.

  Other features and advantages will become more apparent from the detailed description of a shape.

  preferred but not exclusive embodiment of a valve for filling bags with bags according to the present invention, made below with reference to the appended drawings given by way of non-limiting example, in which: - Figure 1 is a perspective and interrupted view of a bag on which is arranged a valve according to the present invention; - 4 - Figure 2 is an interrupted and exploded perspective view of a detail shown in Figure 1; - Figure 3 shows an interrupted and exploded perspective view of another example of a valve according to the present invention; - Figure 4 is a view taken along line IV-IV of Figure 3;

  FIG. 5 shows an interrupted and exploded perspective view of another example of a valve according to the present invention.

  Referring to the drawings, there is generally indicated at 1 a valve intended for filling bags, according to

the present invention.

  The valve 1, in a conventional manner and known per se, essentially comprises a tubular inlet sleeve 2 which is engaged to a bag 3 through an opening

  formed in correspondence of an angle of the latter.

  In particular, the bag 3 has a substantially tubular structure closed at the two opposite ends, only one of which is shown in the appended figures. The closure of the ends of the bag 3 is obtained by the folding inward of the bag 3 of two opposite lateral portions 4 of the above-mentioned tubular structure, so as to create two opposite closing flaps 5. These last 25 are folded one on the other and on the side portions 4 and in this way are glued using paper glue. A reinforcing sheet 6 is also provided which is placed above, and glued to,

  closure flaps 5 and side portions 4.

  It can be noted that the inlet sleeve 2 is essentially interposed between one of the side portions 4 and the closure panels 5 before these are super-

  -5 laid with the aforementioned strap and, obviously, after coating them with glue to obtain their union. In this way the sleeve 2 is securely glued to the portion

  lateral 4 and the closing flaps 5, at the same time preventing their reciprocal union so as to create, in the bag 3, an opening allowing the introduction of the material to be bagged.

  Furthermore and advantageously, according to the present invention, provision is made for the inlet sleeve 2 to be provided, on its inner surface, with a portion 7 coated with plastic material, which extends essentially in a

  plane perpendicular to the main development of the bag 3, over at least half of the extent of the inlet sleeve 2.

  In more detail, in the example shown in FIGS. 1 and 2, the inlet sleeve 2 comprises a first sheet 8 of paper which is glued, by one of its outer surfaces 8a, to the bag 3 in correspondence with the sides. closure 5 and the respective lateral portion 4. A second sheet 9 of plastic, for example of low density polyethylene, is bonded to the first film on 8, on one 8b of its interior surfaces opposite the exterior surface 8a , this sheet 9 realizing, on

  the sleeve 2, the aforementioned coated portion 7.

  The first sheet 8 and the second sheet 9 are reciprocally joined by strips of glue 10. The glue

  of these strips should preferably have characteristics suitable for optimally bonding the paper forming the first sheet 8 to the plastic material forming the second sheet 9 and may therefore be different from that normally used for sticking the bag 3.

  In addition and advantageously, the strips of glue 10 are distributed so as to define, on the sheet 9, along - 6 of an edge oriented towards the inside of the bag 3, a portion

  free 9a, not glued to the first sheet 8. Still referring to the examples shown in FIGS. 1 and 2, the second sheet 9 should have an extent 5 substantially identical to that of the first sheet 8.

  As a result of this, the coated portion 7 extends according to the complete development of the inlet sleeve 2. In this situation, it can advantageously be provided, as clearly visible in FIGS. 1 and 2, that the sleeve 10 2 partially leaves the bag 3, which will make it possible, when the bag 3 has been filled, to close the valve 1 by heat sealing the sleeve 2 on its oriented side

outwards.

  According to what is shown in FIGS. 3 and 4, the second sheet 9 may have, on its side oriented towards the outside of the bag 3, a folded portion 11 arranged

  straddling the corresponding edge of the first sheet 8. The folded portion 11 can advantageously be obtained by simultaneously folding either the second sheet 20 9 or the first sheet 8, according to what is more clearly visible in FIG. 4.

  Another example of a valve 1 is shown in FIG. 5. According to this example, the sleeve 2 comprises, instead of the second sheet 9, a tubular element 12 of plastic material on the outside of which is stuck a

third sheet 13, of paper.

  As can be seen, the third sheet 13 is arranged on the side facing the closure panels, for the effects specified below. It can be noted that, in a manner analogous to what has been described with regard to the reciprocal union between the first sheet 8 and the second sheet 9, also -7 the tubular element 12 is engaged in the third sheet 13 and to the corresponding lateral portion 4 by

  adhesive strips 14 distributed so as to define on the tubular element 12 a free portion 12a, not bonded to the reinforcing sheet 13 and to the lateral portion 4.

  Furthermore and advantageously, in this case also the man

  chon 2 can be provided so that it projects outside the respective bag 3, as described with reference to the example shown in FIGS. 1 and 2.

  After the above description, especially made of a

  from a structural point of view, it is easy to deduce the operation of the valve intended for filling bags having a structure according to the present invention,

  this operation does not deviate considerably from that of known valves.

  In particular, it should be noted that the presence of the free portion 9a of the second sheet 9 or 12a of the tubular element 12 advantageously involves the automatic closing of the valve 1 as soon as the filling of the bag.

  3 from a bagger is finished.

  In this connection, it should be emphasized that several types of automatic bagging machines generally carry out the introduction into the bag of the material to be bagged by means of a jet of air having a high pressure. During bagging, the excess air sent into the bag leaves the latter through

  a series of small holes drilled on purpose.

  When, once the bagging is finished, the passage of air and material through the valve 1 stops, the pressure difference between the inside of the bag 3 and the outside means that the free portion 9a or 12a tends to become fold back on itself, causing automatic closing - 8

  of the valve 1. In this way it advantageously eliminates any air outlet, and therefore of material suspended therein, through the sleeve 2, outlet which otherwise would occur because of the above-mentioned pressure difference.

  The invention achieves the aims. In this regard, it should be emphasized that, since the glue normally used for the manufacture of bags can exclusively stick paper against paper,

  the presence of the coated portion 7 of plastic material 10 inside the sleeve 2 eliminates any risk of being exposed to reciprocal adhesive bonding of the interior surfaces of the sleeve 2.

  In addition and advantageously, as previously mentioned, the valve according to the present invention can be designed so as to allow a hermetic closure by heat sealing, thus eliminating any possible outlet.

bagged material.

  Finally, it should be noted that the presence of the first sheet 8 in the examples shown in FIGS. 1 to 4 and of the third sheet 13 in the example of FIG. 5, allows the optimal connection of the valve 1 to the bag 3 in using machines and adhesives normally used for the manufacture of known valve bags. Obviously, many modifications and variants can be made to the invention without leaving

  however within the framework of its inventive concept.

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Claims (8)

CLAIMS R E V E N D I C A T I O N S   1. Valve for filling bags, comprising a tubular inlet sleeve (2) engaged to one of said bags (3) through an opening formed in correspondence with an angle of the bag, characterized in that said sleeve d the entrance (2) has a portion of its internal surface (7) coated with plastic, which extends, essentially along a plane perpendicular to the main development   cipal of said bag (3), over at least half of the extent 10 of the inlet sleeve (2).   2. Valve according to claim 1, characterized in that said sleeve (2) comprises a first sheet (8) of paper glued, by one of its outer surfaces (8a), to the bag (3) and a second sheet ( 9) of plastic material forming said coated portion (7), said second sheet (9) being glued to the first sheet (8) on an inner surface (8b) of the latter, oriented on the opposite side with respect to said surface ex posterior (8a).   3. Valve according to claim 2, characterized in that said second sheet (9) of plastic material is provided, along one of its sides oriented towards the outside of the bag (3), with a folded portion ( 11) on horseback   on the corresponding edge of said first sheet (8) 25 of paper.   4. Valve according to claim 2, characterized in that said second sheet (9) of plastic material is provided, along one of its edges oriented towards the inside of the bag (3), with a free portion ( 9a) 30 which is not glued to said first sheet (8) of paper. 5. Valve according to claim 1, characterized in - 10 that said coated portion (7) extends according to the development   complete pement of said inlet sleeve (2).   6. Valve according to claim 5, characterized in that said inlet sleeve (2) partially exits the bag (3). 7. Valve according to claim 1, characterized in that said inlet sleeve (2) comprises a tubular element (12) of plastic material bonded to a lateral portion (4) carried by the bag (3) and extending sensitive 10 ment along a plane perpendicular to the main development of said bag (3), outside of said tubular element (12) being glued, on the c8té oriented towards the iron frames meture (5) carried by the bag (3) and superimposed position   relative to the tubular member (12), a third sheet (13) of paper.   8. Valve according to claim 7, characterized in that said tubular element (13) is provided, along one of its edges oriented towards the inside of the bag (3),   a free portion (12a) not glued to the lateral portion 20c (4) and to the third sheet (13) of paper.