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(11) | EP 3 067 290 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | JUTE SACK INCLUDING AIRING WAY |
| (57) Jute sack (1) for bulk goods, such as potatoes and onions, comprising a first wall
(2) and a second wall (3), which walls at a top edge (8) of the sack leave a filling
opening open and which have been attached to each other or merge into each other along
two longitudinal edges (5, 6) and a bottom edge (7) of the sack, wherein the walls
have been formed with jute warp threads (30) and jute weft threads (35) extending
transverse thereto, wherein the weft threads successively alternately pass over the
warp threads and under the warp threads while keeping a distance between the adjacently
extending warp threads and weft threads in order to keep first airing openings (40)
open in between them, wherein at least one of the walls has been provided with an
elongated airing way (24, 25) in which only the warp threads or the weft threads are
present in order to keep second airing openings (42) open in between them, wherein
the airing way has a width exceeding the width of the first airing openings.
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BACKGROUND OF THE INVENTION
[0002] Jute sacks have been used for quite a long time for packaging bulk goods requiring passive ventilation, such as potatoes and onions. Jute has the advantage of being a fully biological material providing the sack with sufficient strength to be used several times. After use the material is fully biodegradable. Synthetic sacks are also available for these bulk goods, however, such sacks do not have this property. Moreover, the bulk goods may as yet go bad more rapidly as a result of long-term spot contact with the synthetic material at the contact locations.
[0003] It is an object of the invention to provide a sack for bulk goods in which bulk goods requiring passive ventilation can be packaged long-term.
SUMMARY OF THE INVENTION
[0004] The invention provides a sack intended to be filled with bulk goods, such as potatoes and onions, comprising a first woven wall and a second woven wall, which walls at a top edge of the sack leave a filling opening open and which have been attached to each other or merge into each other along two longitudinal edges and a bottom edge of the sack, wherein the walls have been formed with jute warp threads and jute weft threads extending transverse thereto, wherein the weft threads successively alternately pass over the warp threads and under the warp threads while keeping a distance between the adjacently extending warp threads and weft threads in order to keep first airing openings open in between them, wherein at least one of the walls has been provided with an elongated airing way in which only the warp threads or the weft threads are present in order to keep second airing openings open in between them, wherein the airing way has a width exceeding the width of the first airing openings.
[0005] The bag according to the invention has walls with jute warp threads and weft threads keeping first ventilation openings open. In addition to being biodegradable, jute has the property of also ventilating around the first ventilation openings and even ventilating at the location contacts or spot contacts with the packaged product. The elongated airing way with second airing openings keeps the bulk goods within the sack and allows the air to pass through very well. Via said elongated airing way the ventilation capacity is increased. It is also possible to force air to pass through the content of the sack via said airing way in order to condition the bulk goods.
[0006] In one embodiment the elongated airing way has a width that is at least twice, preferably at least three times as large as the width of the first airing openings, so that in actual practice sufficient ventilation is obtained through the airing way.
[0007] In one embodiment the first airing openings have a width that is at least twice, preferably at least three times as large as the average thickness of the warp threads and weft threads.
[0008] In one embodiment the warp threads and/or weft threads have an average thickness of 0.40-0.70 mm, preferably 0.50-0.60 mm.
[0009] In one embodiment the elongated airing way is bounded at its longitudinal sides by pairs of twisted closing threads, which opposite each other successively alternately pass over the warp threads or weft threads present and under the weft threads or warp threads present. The twisted closing threads form the transition from the part of the wall with the warp threads and the weft threads to the airing way in which only one of them is present. The warp threads properly keep the warp threads and weft threads in the mutual bond.
[0010] In one embodiment thereof the pairs of twisted closing threads extend at distance from the warp threads or weft threads extending adjacent thereto in order to keep third airing openings open in between them.
[0011] In one embodiment, the third airing openings have a width transverse to the elongated airing way, that is smaller than or equal to the width of the first airing openings.
[0012] In one embodiment the closing threads have an average thickness that is smaller than the average thickness of the warp threads and weft threads, so that the pairs of twisted closing threads together form a compact package in the fabric.
[0013] In one embodiment the closing threads are of jute, so that the sack can be fully biodegradable.
[0014] In one embodiment the closing threads have an average thickness of 0.10-0.50 mm, preferably 0.20-0.40 mm.
[0015] In one embodiment the elongated airing way extends parallel to the longitudinal edges or the top edge or bottom edge.
[0016] In one embodiment thereof the elongated airing way extends at a distance from the closest longitudinal edge, top edge or bottom edge in question, which distance is smaller than 1/3, preferably smaller than 1/4 of the width of the sack between the longitudinal edges. In the filled, bulging condition of the sack these edge areas of the walls will be upright. Said edge areas will then be inclined or transverse to the middle section. When the sack is included in a stack, the edge areas, and therefore the airing way, will remain freely accessible for ventilation from the side of the stack.
[0017] In one embodiment the at least one wall has been provided with a middle section in which the warp threads and the weft threads are both present, wherein the elongated airing way extends along the middle section or up to the middle section. Said even middle section can be used for being printed on or a label.
[0018] In one embodiment the front wall and/or the rear wall have been provided with a middle section in which the warp threads and the weft threads are both present, wherein a label has been attached to the middle section.
[0019] In one embodiment thereof an airing way extends between the middle section and the longitudinal edges.
[0021] In one embodiment the front wall and the rear wall have been provided with an elongated airing way or several elongated airing ways.
[0022] In one embodiment, in an upper area either near or adjacent to their top edges, the first wall and the second wall have each been provided with a layer of added material attached thereto, which material forms a strip extending parallel to the top edge, wherein a suspension opening extends through the layer of added material and the wall onto which it has been attached. The strip of added material can be used to suspend the jute sack with the suspension opening from a suspension pin in order for several sacks to form a supply of adjacently placed sacks that can be taken off by suction cups that engage onto the strip of added material.
[0023] In one embodiment thereof, pairs of suspension openings extend through the layer of added material and the wall onto which it has been attached, so that parallel suspension pins can be used to keep the sacks properly oriented.
[0024] Engagement by suction cups can take place properly when the layers of added material have been attached to the exterior of the walls.
[0025] In one embodiment the layers of added material have the form of a sheet, in particular the form of foil.
[0026] In order for the suction cups to work optimally the layers of added material can be air-impermeable.
[0027] In one embodiment the layers of added material are a synthetic material, in particular a polyolefin, such as polyethene or polypropene or PVC.
[0029] The invention furthermore provides a method for manufacturing a jute sack intended to be filled with bulk goods, such as potatoes and onions, wherein the method comprises weaving jute warp threads and jute weft threads into a continuous web of fabric having first airing openings between the warp threads and weft threads, wherein in a part of the fabric an elongated airing way has been formed as only the warp threads or the weft threads are present in there in order to keep second airing openings open in between them, wherein the airing way has a width exceeding the width of the first airing openings, and folding down the fabric onto itself and taking off a same part of the fabric consecutive thereto from the web of fabric, wherein the folded down part of the web of fabric is attached along two edges to the part of the web of fabric consecutive thereto and a filling opening for the sack is left open along one edge.
[0030] In one embodiment, either near or adjacent to the side edge of the web of fabric, a layer of added material is attached to the web of fabric forming a strip extending parallel to the side edge, wherein, when folding down the web of fabric, the strip of added material ends up at the exterior of the sack, wherein a suspension opening is made through the layer of added material and the wall onto which it has been attached.
[0032] The aspects and measures described in this description and the claims of the application and/or shown in the drawings of this application may where possible also be used individually. Said individual aspects may be the subject of divisional patent applications relating thereto. This particularly applies to the measures and aspects that are described per se in the sub claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] The invention will be elucidated on the basis of a number of exemplary embodiments shown in the attached drawings, in which:
Figures 1A and 1B show a side view and an isometric view of a jute sack including airing ways according to a first embodiment of the invention;
Figure 2 shows a detail of the fabric of the jute sack according to figures 1A and 1B;
Figures 3A and 3B show side views of a jute sack including airing ways according to a second embodiment of the invention;
Figures 4A and 4B show a side view and an isometric view of a jute sack including airing ways according to a third embodiment of the invention;
Figure 5 shows a method for manufacturing the jute sack according to the first embodiment; and
Figure 6 shows a method for manufacturing the jute sack according to the third embodiment.
DETAILED DESCRIPTION OF THE DRAWINGS
[0034] Figures 1 and 2 show a jute sack 1 according to a first embodiment of the invention. The sack 1 is intended to be filled with bulk goods, such as onions, potatoes or their seedlings. The sack 1 comprises a front wall 2 and a rear wall 3 which in the empty condition of the sack 1 define a rectangular outer contour. The sack 1 then has a straight left longitudinal edge 5, a straight right longitudinal edge 6, a straight bottom edge 7 and a straight top edge 8.
[0035] The material of the walls 2, 3 is a fabric 20 with jute. In this example at the left longitudinal edge 5 the fabric 20 merges from the one side to the other due to folding down, and has been attached to each other along the bottom edge 7 and the right longitudinal edge 6 by means of a jute or cotton stitching 10. Along the top edge 8 the fabric 20 has been provided with a stitched turnup 11 bounding a filling opening 12 of the sack 1. In the fabric 20, elongated airing ways 24, 25 have been formed that extend parallel to each other and parallel to the longitudinal edges 5, 6. In this example the airing ways 24, 25 extend from the bottom edge 7 up to the top edge 8. The outermost airing ways 24 are at a distance A relative to the closest longitudinal edge 5, 6, of less than 1/3 of the transversely thereto oriented width B of the sack 1 between the longitudinal edges 5, 6. As a consequence, when the sack 1 has been filled and with its bulging walls 2, 3 has been stacked onto another sack 1, the outermost airing ways 24 are situated on the free side of the stack for ventilating the contained goods.
[0036] The fabric 20 is shown in detail in figure 2. The fabric 20 contains jute warp threads 30 or yarn which in this example extend over the full width B of the sack 1, and groups 21 of jute weft threads 35 or yarn that consecutively alternately pass over the warp threads 30 and under the warp threads 30 with a specific distance between the warp threads 30 and weft threads 35 extending adjacent to each other. As a result, first airing openings 40 having a square contour have been kept open within the groups 21 of weft threads 35. Their width is at least twice, preferably at least three times as large as the average thickness of the warp threads 30 and weft threads 35. Within the groups 21 of weft threads 30, the warp threads 30 have an undulated section 32 and a straight section 31 in the airing ways 24, 25. As a result elongated second airing openings 42 have been kept open in the airing ways 24, 25, which openings in the longitudinal direction are transverse to the longitudinal direction of the airing ways 24, 25. The width of the second airing openings 42 approximately equals the width of the first airing openings 40.
[0037] The fabric 20 has been provided with pairs of twisted cotton closing threads 36, 37 or yarn bounding the airing ways 24, 25 at the longitudinal sides. The closing threads 36, 37 have a thickness that is smaller than the average thickness of the warp threads 30 and weft threads 35. The closing threads 36, 37 opposite each other consecutively pass over the warp threads 30 present in this example and under the warp threads 30 present. As a result, third airing openings 43 having a square contour have been kept open between the groups 21 of weft threads 35 and the closing threads 36, 37. Their width approximately equals the width of the first airing openings 40. The airing ways 24, 25 have a width, or the second airing openings 42 have a length that is at least three times as large as the width of the first airing openings 40.
[0038] The first airing openings 40 provide a degree of ventilation that is known per se for sacks with jute fabric. However, the much larger second airing openings 42 of the airing ways 24, 25 that are kept reliably open by the closing threads 36, 37 provide an additional ventilation that is beneficial to the storage life of the bulk goods.
[0039] Figures 3A and 3B show a jute sack 101 according to a second embodiment of the invention. Characteristics that correspond with the jute sack 1 according to the first embodiment have been given the same reference numbers. Below only the differences will be discussed.
[0040] In its front wall 2 and/or rear wall 3 the sack 101 has been provided with the same outermost airing ways 24, whereas the inner airing ways 125 have been interrupted. This results in the walls 2, 3 being provided with a rectangular middle section 50 in which the warp threads 30 and weft threads 35 are both present to form an attachment surface for a label 51. The label 51 is affixed to, glued to or fused with the middle section 50.
[0041] Figures 4A and 4B show a jute sack 201 according to a third embodiment of the invention. Characteristics that correspond with the jute sack 1 according to the first embodiment have been given the same reference numbers. Below only the differences will be discussed.
[0042] The sack 201 comprises the same front wall 2 and rear wall 3, which in the empty condition of the sack 201 define a rectangular contour outer contour, and the straight left longitudinal edge 5, the straight right longitudinal edge 6, the straight bottom edge 7 and the straight top edge 8. The material of the walls is the same fabric 20 with jute as described above. A strip or band of added material, in this example a strip of foil 60, has been arranged on the exterior of the front wall 2 and the rear wall 3 either near or adjacent to the top edge 8. The strip of foil has been made of a synthetic material, in particular a polyolefin, such as polyethene or polypropene or PVC. The strip of foil 60 has been attached to the fabric 20 or has been formed in a laminating or coating process. Heat is then supplied so that the foil 60 becomes viscous, soft, plastic, for instance by ironing, after which the strip of foil 60 has been cooled rapidly. A part of the abutting surface will thus be fused and adhered to the fibres of the jute.
[0043] The sack 201 has been provided with two pairs of suspension openings 62 that both at the front wall 2 and the rear wall 3 extend through the strip of foil 60 and the fabric 20. The pairs of suspension openings 62 are in the middle of the strip of foil 60 and have been aligned with each other. As a result, several empty sacks 201 can be slid over parallel straight suspension pins that have not been shown. The sacks 201 then hang down parallel against each other in order to form a supply that can be mechanically pulled off from the suspension pins. Taking them off takes place by means of suction cups that engage onto the air-impermeable strip of foil 60 and then move away from the supply parallel to the suspension pins. In that case each time the front sack 201 will be opened at the filling opening 12 and subsequently be taken from the supply. The sack 201 has been provided with several airing ways 24, 25 extending parallel to the strip of foil 60 over the full width between the left longitudinal edge 5 and the straight right longitudinal edge 6.
[0044] The jute warp threads 30 and weft threads 35 have a thickness of between 0.40 and 0.70 mm, preferably between 0.50 and 0.60 mm, preferably approximately 0.55 mm. The warp threads 30 and the weft threads 35 are single-layered yarn having 4-5 revolutions per inch. The cotton closing threads 36, 37 have a thickness of 0.10-0.50 mm, preferably 0.20-0.40 mm, preferably approximately 0.30 mm. The closing threads 36, 37 are three-layered yarn having 9-10 revolutions per inch. The tensile strength of said closing threads 36, 37 exceeds the tensile strength of the thicker jute warp threads 30 and weft threads 35. In the above text the terms 'warp threads' and 'weft threads' have been used to distinguish between the various threads of which the fabric 20 consists. These terms do not limit the way of production, in particular the weaving technique, of the fabric 20.
[0045] Figure 5 schematically shows a manufacturing process for the jute sack 1 according to a first embodiment. Figure 5 shows a weaving machine 600 with which a continuous web 601 of the fabric 20 is formed. The continuous web 601 leaves the weaving machine 600 in direction D, wherein the continuous web 601 has been provided with airing ways 24, 25 extending transverse to the longitudinal direction or discharge direction D. Each time an end part 603 of the continuous web 601 is folded down backwards in direction F towards the continuous web 601 and a same consecutive part 604 is separated from the continuous web 601 in direction G. The folded edge then forms the left longitudinal edge 5 of the sack 1, the end part 603 forms the rear wall 3 and the consecutive part 604 onto which the end part is folded down forms the front wall 2. They are subsequently provided with the stitching 10 along the bottom edge 7 and the right longitudinal edge 6. The stitched turnup 11 can be made along the top edge 8.
[0046] Figure 6 schematically shows a manufacturing process for the jute sack 201 according to the third embodiment. Figure 6 shows a weaving machine 600 with which a continuous web 602 of the fabric 20 is formed. The continuous web 602 leaves the weaving machine 600 in direction D, wherein the continuous web 602 has been provided with airing ways 24, 25 extending in longitudinal direction or discharge direction D. After leaving the weaving machine 600 the strip of foil 60 is applied along one side edge by means of a schematically shown lamination or coating device.
[0047] Each time an end part 603 of the continuous web 602 is folded down backwards in direction F towards the continuous web 602 and a same consecutive part 604 is separated from the continuous web 601 in direction G. The folded edge then forms the left longitudinal edge 5 of the sack 201, the end part 603 forms the rear wall 3 and the consecutive part 604 onto which the end part is folded down forms the front wall 2. They are subsequently provided with the stitching 10 along the bottom edge 7 and the right longitudinal edge 6. The stitched turnup 11 can be made along the top edge 8, where the strip of foil 60 is situated. Finally, the pairs of suspension openings 62 are formed by means of punching or perforation.
[0048] The above description has been included to illustrate the operation of preferred embodiments of the invention and not to limit the scope of the invention. Starting from the above explanation many variations that fall within the spirit and scope of the present invention will be evident to an expert.
1. Jute sack intended to be filled with bulk goods, such as potatoes and onions, comprising
a first woven wall and a second woven wall, which walls at a top edge of the sack
leave a filling opening open and which have been attached to each other or merge into
each other along two longitudinal edges and a bottom edge of the sack, wherein the
walls have been formed with jute warp threads and jute weft threads extending transverse
thereto, wherein the weft threads successively alternately pass over the warp threads
and under the warp threads while keeping a distance between the adjacently extending
warp threads and weft threads in order to keep first airing openings open in between
them, wherein at least one of the walls has been provided with an elongated airing
way in which only the warp threads or the weft threads are present in order to keep
second airing openings open in between them, wherein the airing way has a width exceeding
the width of the first airing openings.
2. Jute sack according to claim 1, wherein the elongated airing way has a width that
is at least twice, preferably at least three times as large as the width of the first
airing openings.
3. Jute sack according to any one of the preceding claims, wherein the first airing openings
have a width that is at least twice, preferably at least three times as large as the
average thickness of the warp threads and weft threads.
4. Jute sack according to any one of the preceding claims, wherein the elongated airing
way is bounded at its longitudinal sides by pairs of twisted closing threads, preferably
made of cotton, which opposite each other successively alternately pass over the warp
threads or weft threads present and under the weft threads or warp threads present.
5. Jute sack according to claim 4, wherein the pairs of twisted closing threads extend
at distance from the warp threads or weft threads extending adjacent thereto in order
to keep third airing openings open in between them, wherein the third airing openings
preferably have a width transverse to the elongated airing way, that is smaller than
or equal to the width of the first airing openings.
6. Jute sack according to any one of the claims 4 or 5, wherein the closing threads have
an average thickness that is smaller than the average thickness of the warp threads
and weft threads.
7. Jute sack according to any one of the preceding claims, wherein the elongated airing
way extends parallel to the longitudinal edges or the top edge or bottom edge, wherein
the elongated airing way preferably extends at a distance from the closest longitudinal
edge, top edge or bottom edge in question, which distance is smaller than 1/3, preferably
smaller than 1/4 of the width of the sack between the longitudinal edges.
8. Jute sack according to any one of the preceding claims, wherein the front wall and/or
the rear wall have been provided with a middle section in which the warp threads and
the weft threads are both present, wherein a label has been attached to the middle
section, wherein preferably an airing way extends between the middle section and the
longitudinal edges.
9. Jute sack according to any one of the preceding claims, wherein in an upper area either
near or adjacent to their top edges, the first wall and the second wall have each
been provided with a layer of added material attached thereto, which material forms
a strip extending parallel to the top edge, wherein a suspension opening extends through
the layer of added material and the wall onto which it has been attached, wherein
preferably pairs of suspension openings extend through the layer of added material
and the wall onto which it has been attached.
10. Jute sack according to claim 9, wherein the layers of added material have been attached
to the exterior of the walls.
11. Jute sack according to claims 9 or 10, wherein the layers of added material have the
form of a sheet, in particular the form of foil.
12. Jute sack according to any one of the claims 9-11, wherein the layers of added material
are air-impermeable.
13. Jute sack according to any one of the claims 9-12, wherein the layers of added material
are a synthetic material, in particular a polyolefin, such as polyethene or polypropene
or PVC.
14. Method for manufacturing a jute sack intended to be filled with bulk goods, such as
potatoes and onions, wherein the method comprises weaving jute warp threads and jute
weft threads into a continuous web of fabric having first airing openings between
the warp threads and weft threads, wherein in a part of the fabric an elongated airing
way has been formed as only the warp threads or the weft threads are present in there
in order to keep second airing openings open in between them, wherein the airing way
has a width exceeding the width of the first airing openings, and folding down the
fabric onto itself and taking off a same part of the fabric consecutive thereto from
the web of fabric, wherein the folded down part of the web of fabric is attached along
two edges to the part of the web of fabric consecutive thereto and a filling opening
for the sack is left open along one edge.
15. Method according to claim 14, wherein either near or adjacent to the side edge of
the web of fabric a layer of added material is attached to the web of fabric forming
a strip extending parallel to the side edge, wherein, when folding down the web of
fabric, the strip of added material ends up at the exterior of the sack, wherein a
suspension opening is made through the layer of added material and the wall onto which
it has been attached, wherein the airing way preferably extends parallel to the strip
of added material.