The present disclosure relates to apparatus for treatment of a work such as a fibrous web or a liquid-absorbent structure and more particularly to work treating apparatus provided with an injection unit adapted to inject pressurized steam.
Work treating apparatus provided with an injection unit adapted to inject pressurized steam from an injection plate toward a work is known. For example, PATENT DOCUMENT 1 discloses a work treating apparatus adapted to inject pressurized steam from injection orifices to a laminated sheet web comprising upper and lower fibrous webs and liquid-absorbent materials sandwiched between these fibrous webs so that the liquid-absorbent materials may be subjected to press working in a wetted state. PATENT DOCUMENT 2 discloses a work treating apparatus adapted to convey a work sandwiched between upper and lower mesh belts in a machine direction and to inject pressurized steam from the injection unit to the work surface.
In the case of the work treating apparatus disclosed in PATENT DOCUMENT 1, liquid-absorbent materials can be subjected to press work in a wetted state and thereby fibrous webs covering the liquid-absorbent materials from above can be kept in close contact with the liquid-absorbent materials. In this way, fine particles of the liquid-absorbent materials can be prevented from leaking through the upper surface and the laminated sheet can be protected against being hardened. In the case of the work treating apparatus disclosed in PATENT DOCUMENT 2, pressurized steam is injected to a work through openings of the mesh belt and thereby the work's surface can be protected against being damaged.
However, in the two sets of work treating apparatus disclosed in PATENT DOCUMENTS 1 and 2, the injection orifices are spaced from a work by a given distance and, in consequence, injected pressurized steam may be cooled before reaching the work surface and form drops of water accumulating on the laminated sheet. As a result, pressurized steam could not reach liquid-absorbent materials sandwiched between the fibrous webs. In the case of PATENT DOCUMENT 2, even when pressurized steam is injected to the work from the injection orifices kept in slidable contact with the mesh belt in order to prevent the temperature of pressurized steam from dropping, it is impossible to inject pressurized steam to a work at a constant temperature if the mesh belt is knitted one. It is for the reason that, in such a case, the region of the mesh belt adapted to come in contact with the work surface includes undesirable irregularities.
At least a first aspect of the present invention is characterized in features as will be described below: a work treating apparatus having a machine direction, a cross direction being orthogonal to the machine direction, comprising a conveyor serving to convey a work in the machine direction and an injection unit serving to inject superheated and pressurized steam jets to the work.
In this apparatus, the injection unit has a lower surface provided with a plurality of injection orifices arranged in the cross direction; the conveyor is flexible and comprises a first mesh belt facing to an upper surface of the work and a second mesh belt facing to a lower surface of the work wherein the first and second mesh belts cooperate with each other to sandwich the work therebetweeen and to convey the work in the machine direction; and the lower surface comes in slidable contact with the first mesh belt to bend at least the first mesh belt of the first and second mesh belts downward.
In
Referring to
The conveyor 12 comprises a pair of endless belts circulating in one direction, i.e., first and second mesh belts 12a, 12b adapted to convey the work 11 sandwiched therebetween in the machine direction MD and, to this end, these mesh belts 12a, 12b are supported and driven by a plurality of feed rolls to run in the machine direction MD. More specifically, the conveyor 12 are supported and driven by at least a pair of feed rolls, i.e., first and second feed rolls 16, 17 underlying the conveyor 12 and respectively located on both sides in the machine direction MD of the injection unit 14. It should be appreciated here that, in the course of conveying the work 11 in the machine direction MD, the conveyor 12 may be adapted to compress the work 11 in its thickness direction in addition to sandwiching the work 11.
The first and second mesh belts 12a, 12b are flexible and may be formed, for example, by a metallic wire product made of stainless alloy or bronze, a plastic product made of woven fibers such as polyester fibers or aramid, or by a perforated metallic plate. According to the present embodiment, the open area ratio of the first and second mesh belts 12a, 12b may be in a range of about 10 to about 85%, their wire diameter may be in a range of about 0.03 to about 5.0 mm and their mesh density may be in a range of about 2 to about 600 per inch. It should be appreciated here that an open area ratio, a wire diameter and a mesh density of the first and second mesh belts may be appropriately set by skilled artisans depending on various factors such as steam pressure of the pressurized steam jets and materials or structure of the work. The first and second mesh belts 12a, 12b may be different from each other in the open area ratio and/or in the mesh density. For example, the first mesh belt 12a may have a mesh density higher than that of the second mesh belt 12b.
The injection unit 14 comprises the steam piping unit 20 having a steam supply pipe 19 into which superheated and pressurized steam supplied from a steam supply unit 18 such as a boiler is introduced and an injection plate 21 fixed to the steam piping unit 20. Instead of separately providing the steam piping unit 20 and the injection plate 21, these two members may be formed as a single member so far as desired superheated and pressurized steam jets can be injected.
Referring to
Referring to
Referring to
Referring to
Referring to
When the pressurized steam jets are injected from the injection orifices 31 opening in the lower surface 32 of the injection plate 21 toward the work 11, a distance between the open ends of the respective injection orifices 31 and the work 11 is substantially zero. In consequence, the pressurized steam jets can be injected from the injection orifices 31 to the work 11 without any leakage, i.e., at the optimum injection efficiency. In the course of continuously treating the work 11, more or less air flow would otherwise be induced by travel of the conveyor 12 in the machine direction MD and such air flow would be apt to cool the vicinity of the injection orifices 31 of the lower surface 32. Particularly when the work 11 is significantly spaced from the injection orifices 31, the pressurized steam jets would be cooled to form drops of water accumulating on the surface of the work 11. However, according to the present embodiment, the pressurized steam jets can be injected directly to the work 11 without contact with ambient air and the pressurized steam jets would not be cooled to form drops of water accumulating on the surface of the work 11. In addition, the work treating apparatus 10 according to the present embodiment is adapted to inject the pressurized steam jets to the work 11 via the first mesh belt 12a so that the work 11 may be injected with the pressurized steam jets under constant conditions such as the distance from the injection orifices 31 to the work 11, the temperature of the pressurized steam jets and the quantity of injected steam jets per unit time. If the injection orifices 31 are keep in slidable contact with the work 11 without interposing the first mesh belt 12a, fibers constituting the work 11 might be partially fusion-bonded one to another when a temperature in the vicinity of the injection orifices 31 of the injection plate 21 is higher than a melting point of the work 11. Furthermore, when thickness of the work 11 is uneven, the injection plate 21 partially can not be kept in slidable contact with the work 11 and injection of the pressurized steam jets to the work 11 can not be stabilized. In addition, in such a case, surface fibers in the region coming in slidable contact with the injection plate 21 may be disordered, leading to deterioration of the product quality.
As has previously been described, the lower surface 32 of the injection plate 21 is not merely kept in slidable contact with the first mesh belt 12a, in the region R defined between the first and second feed rolls 16, 17 and subjected to a tension higher than in the remaining region, the lower surface 32 of the injection plate 21 comes in slidable contact with the first mesh belt 12a in the manner that the lower surface 32 forces the first mesh belt 12a to be slightly bend downward during injection of the pressurized steam. Consequentially, even if the first mesh belt 12a is formed of a knitted polyester fiber web or the like and its surface has irregularities, the work 11 can be evenly and reliably injected with the pressurized steam. Of the conveyor 12, in order to deform at least the first mesh belt 12a in a desired curved shape, the first mesh belt 12a has hardness lower than that of the lower surface 32 of the injection plate 21, more specifically, the lower surface 32 of the injection plate 21 preferably has hardness Hv in a range of about 300 to about 1200 and the first mesh belt 12a preferably has hardness lower than this level.
Referring to
Referring to
Referring to
As has previously been described, the work treating apparatus 10 according to the present invention is not used for any specific treatment but may be used in various fields of treatment such as fusion-bonding of fibers having relatively low fusion temperatures, texture treatment of nonwoven fabric sheets and cleaning of textile oil.
The terms “first” and “second” herein are used merely for distinguishing between similar elements.
The aspects of the present invention described above may be arranged in at least the following item(s):
(i) A work treating apparatus having a machine direction, a cross direction being orthogonal to the machine direction, comprising a conveyor serving to convey a work in the machine direction and an injection unit serving to inject superheated and pressurized steam jets to the work, wherein:
the injection unit has a lower surface provided with a plurality of injection orifices arranged in the cross direction;
the conveyor is flexible and comprises a first mesh belt facing to an upper surface of the work and a second mesh belt facing to a lower surface of the work wherein the first and second mesh belts cooperate with each other to sandwich the work therebetweeen and to convey the work in the machine direction; and
the lower surface comes in slidable contact with the first mesh belt to bend at least the first mesh belt of the first and second mesh belts downward.
The aspect of the present invention described in the above item (i) may provide one or more of the following advantageous effects:
When the lower surface of the injection unit forces the first mesh belt to be curved downward as the lower surface is being in slidable contact with the first mesh belt, there is generally no distance between the injection orifices and the work and a temperature of pressurized steam jets would not drop. In this way, a high efficiency of injection is assured. The lower surface of the injection unit is not only kept in slidable contact with the first mesh belt but also forces the first mesh belt to be convexly deformed downward and thereby ensures that the work surface can be treated with pressurized steam jets kept at a constant temperature even if the mesh belt has irregularities on its surface.
Additionally, one or more of the following embodiments are provided in accordance with further aspects:
(ii) Both the first and second mesh belts may be bent downwards by the lower surface of the injection unit.
(iii) The second mesh belt may be harder than the first mesh belt and only the first mesh belt may be bent downwards by the lower surface of the injection unit.
(iv) A pair of feed rolls spaced from each other by a given distance in the machine direction may be located below regions of the conveyor facing the injection unit so that the conveyor is slightly uplifted by the pair of feed rolls and thereby the regions of the second mesh belt are subjected to a tension higher than that to which the remaining region of said conveyor facing said injection unit is subjected wherein the lower surface of the injection unit comes in slidable contact with the first mesh belt in the region.
The remaining region of said conveyor facing said injection unit is preferably located between the feed rolls in the machine direction.
(v) The injection orifices are preferably provided in a section of the lower surface of the injection unit that is arranged to contact the first mesh belt.
(vi) The lower surface of the injection unit as a whole is preferably convex downwards and contacts the first mesh belt at the lowermost point of the lower surface of the injection unit.
(vii) The lower surface of the injection unit preferably comprises a central section and an upstream section extending downward from an upstream edge of the injection unit to the central section in the machine direction and the central section being horizontal wherein a border of the central section and the upstream section is curved without any corners.
(viii) The lowermost section is preferably a central section between the upstream section and a downstream section, the downstream section extending upwards from said lowermost section to a downstream edge of said injection unit in said machine direction.
Preferably, a border of said central section and said downstream section is curved without any corners.
(vix) Preferably, the injection orifices are provided in the lowermost section.
(x) Preferably, the section of the lower surface of the injection unit which contacts the first mesh belt is located at a level lower than the level at which the feed rolls contact the second mesh belt.
The lower surface of the injection unit may be located at a level lower than respective central axes of the first and second feed rolls.
(xi) An upper surface of the first mesh belt is preferably higher than the section of the lower surface of the injection unit that is arranged to contact the first mesh belt, on at least the upstream side of the section of the lower surface of the injection unit that is arranged to contact the first mesh belt.
The upper surface of the first mesh belt is preferably higher than the section of the lower surface of the injection unit that is arranged to contact the first mesh belt on both the upstream and downstream sides.
(xii) Preferably, on the upstream side only of the injection unit in the machine direction, a bulkhead is provided to block air flowing from upstream into the region.
(xiii) On each of the upstream and downstream sides of said injection unit in said machine direction, a bulkhead may provided to block air flowing into said region.
(xiv) Each bulkhead may be in slidable contact with the conveyor means. Preferably each bulkhead is in slidable contact with an upper surface of the first mesh belt.
(xv) A heating box may be provided to enclose the injection unit and a region of the conveyor corresponding to the injection unit.
According to the embodiments in the above (ii) to (xv), the features of which may be taken in isolation or in any combination, the advantageous effect(s) set forth at (a) is/are better ensured. Further advantageous effects of the respective embodiments may be obtained as discussed in the respective related descriptions.
Number | Date | Country | Kind |
---|---|---|---|
2010-059939 | Mar 2010 | JP | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/JP2011/001562 | 3/16/2011 | WO | 00 | 8/24/2012 |