Patent Application
20160251779
The present invention relates to a bulk recovery apparatus for nonwoven fabric and a bulk recovery method for nonwoven fabric.
Sanitary napkins and disposable diapers have been conventionally used as absorbent articles. And pee pads for pets included within the category of the above absorbent articles are also widely used as toilets for pets. A liquid permeable top sheet is provided to the part of such absorbent articles which contacts such as the user's skin. And recently, bulky nonwoven fabric is preferred as the material of the top sheet since a high capturing performance is required from the viewpoint of reducing the sticky touch felt by the skin.
Such nonwoven fabric is manufactured in a strip form by appropriate methods such as the carding method, and are wound in a rolled form thereafter to be stored in states of nonwoven fabric rolls. And the nonwoven fabric roll is brought to the absorbent article manufacturing line when the nonwoven fabric is to be used, then the nonwoven fabric is unrolled from the above nonwoven fabric roll at the above manufacturing line to be used as the material for the top sheet.
Meanwhile, tensile force in the winding direction is applied in order to avoid the nonwoven fabric from meandering and the like when winding the nonwoven fabric into a roll of nonwoven fabric. For such reason, the nonwoven fabric is usually wound tightly by this tensile force. In other words, this nonwoven fabric is compressed in the thickness direction to be in a state such that the bulkiness is reduced. Therefore, only nonwoven fabric with its bulk reduced would be unrolled and provided when the nonwoven fabric is unrolled from the nonwoven fabric roll at the absorbent article manufacturing line, that is, the aforementioned requirement of a bulky nonwoven fabric would not be met.
There is known, as a method of increasing the bulk of nonwoven fabric, a process such as blowing hot air against the surface of the nonwoven fabric to heat the surface of the nonwoven fabric so that the fibers of the compressed nonwoven fabric would return to its initial state. PTL 1 discloses, for example, a method of preparing a heating chamber for heating nonwoven fabric and blowing hot air into either the entrance side or the exit side when the nonwoven fabric is transferred from the entrance side to the exit side of the heating chamber. The hot air blown into the heating chamber is discharged from the other side of the entrance or the exit so to flow along the surface of the nonwoven fabric in the heating room allowing the nonwoven fabric to recover its bulk.
[PTL 1] Japanese Laid-open Application No. 2012-097087
The bulk recovery apparatus heats the nonwoven fabric to soften the nonwoven fabric. Therefore, the nonwoven fabric can easily stretch in the transfer direction when tensile strength in the transfer direction acts thereagainst. And in a case when the hot air flows along the surface of the nonwoven fabric as in PTL 1, the nonwoven fabric can further easily stretch in the transfer direction by being pulled by the hot air flow when the speed (flow rate) of the hot air flow is fast. Particularly, the nonwoven fabric would be subject to the hot air and heated for a long time at the downstream side along the transfer direction in the heating chamber so that the effects by the stretching of the nonwoven fabric would increase when the flow rate of the hot air is too fast in the above area and thus it would be difficult to perform a normal bulk recovery.
The present invention has been made in view of the above circumstances and an objective thereof is to appropriately adjust the flow rate of the hot air in a device that performs bulk recovery by blowing the hot air against the nonwoven fabric being transferred.
A main aspect of the invention for achieving the above objective is an apparatus that recovers a bulk of a nonwoven fabric by blowing hot air and heating the nonwoven fabric that is transferred in a transfer direction, including: a case member that has both end portions thereof in the transfer direction opened; an entrance that is provided to an opening on one end side, in the transfer direction, of the case member, the entrance being used to transfer the nonwoven fabric; an exit that is provided to an opening on an other end side, in the transfer direction, of the case member, the exit being used to transfer the nonwoven fabric; and a blast opening that is provided to a part on the entrance side of the case member and blasts into a space inside the case member the hot air toward a part on the exit side, wherein a sectional area at a first position, of the space inside the case member, on a downstream side along the transfer direction with respect to a position where the blast opening is provided, is wider than a sectional area at a second position, of the space inside the case member, located between the position where the blast opening is provided and the first position and the hot air that is blasted from the blast opening flows from an upstream side along the transfer direction through the first and second positions and to the downstream side along the transfer direction while coming into contact with one face of two faces of the nonwoven fabric in the space inside the case member.
Other features of the present invention will be made clear through the present specification with reference to the accompanying drawings.
According to the present invention, the flow rate of the hot air can be appropriately adjusted in a device that performs bulk recovery by blowing the hot air against the nonwoven fabric being transferred.
At least the following matters will become clear through the description of the present specification and the accompanying drawings.
An apparatus that recovers a bulk of a nonwoven fabric by blowing hot air and heating the nonwoven fabric that is transferred in a transfer direction, including: a case member that has both end portions thereof in the transfer direction opened; an entrance that is provided to an opening on one end side, in the transfer direction, of the case member, the entrance being used to transfer the nonwoven fabric; an exit that is provided to an opening on an other end side, in the transfer direction, of the case member, the exit being used to transfer the nonwoven fabric; and a blast opening that is provided to a part on the entrance side of the case member and blasts into a space inside the case member the hot air toward a part on the exit side, wherein a sectional area at a first position, of the space inside the case member, on a downstream side along the transfer direction with respect to a position where the blast opening is provided, is wider than a sectional area at a second position, of the space inside the case member, located between the position where the blast opening is provided and the first position and the hot air that is blasted from the blast opening flows from an upstream side along the transfer direction through the first and second positions and to the downstream side along the transfer direction while coming into contact with one face of two faces of the nonwoven fabric in the space inside the case member.
According to such a bulk recovery apparatus for nonwoven fabrics, the flow rate of the hot air can be reduced by expanding the hot air flow path area (sectional area) in a downstream side area along the transport direction. Hereby, the flow rate of the hot air is appropriately adjusted so to restrain the nonwoven fabric from stretching in the transfer direction which in turn allows a normal bulk recovery to be performed.
It is preferable that in the nonwoven fabric bulk recovery apparatus, an area that includes the first position and has a sectional area wider than that at the second position, in the space inside the case member has provided a discharge opening that discharges to an outside the hot air blasted in the space inside the case member.
According to such a bulk recovery apparatus for nonwoven fabrics, the volume of the hot air can be reduced in the downstream side area along the transport direction by discharging from the discharge opening a part of the hot air blasted into the case member. Hereby, the flow rate of the hot air at the downstream side area along the transport direction can be reduced.
It is preferable that in the nonwoven fabric bulk recovery apparatus, the discharge opening is provided to a location vertically shifted from a path along which the nonwoven fabric is transferred.
According to such a bulk recovery apparatus for nonwoven fabrics, issues relating to the transfer operation of the nonwoven fabric being interfered and the like by the effects due to the flow caused by the hot air being discharged from the discharge opening is unlikely to occur so that a correct transfer operation of the nonwoven fabric can be performed.
It is preferable that in the nonwoven fabric bulk recovery apparatus, the blast opening and the discharge opening are both provided at locations vertically shifted to a same side with respect to the path along which the nonwoven fabric is transferred.
According to such a bulk recovery apparatus for nonwoven fabrics, the hot air blasted from the blast opening which is provided to the upstream side in the transfer direction would flow along the transfer direction without penetrating the nonwoven fabric and be discharged outside from the discharge opening provided to the downstream side along the transfer direction. Hereby, one face of the nonwoven fabric (e.g., lower face side of the nonwoven fabric) can be heated sufficiently which in turn allows an effective bulk recovery.
It is preferable that in the nonwoven fabric bulk recovery apparatus, a member that blocks a part of a space on an exit side of the space inside the case member is provided at a part most downstream along the transfer direction in the space inside the case member.
According to such a bulk recovery apparatus for nonwoven fabrics, the flow of the hot air is narrowed by reducing the sectional area of the exit portion of the case member allowing regulation of the hot air flow. Hereby, the transfer operation of the nonwoven fabric at the above exit portion is unlikely to be disturbed so that a stable bulk recovery operation can be performed.
It is preferable that the nonwoven fabric bulk recovery apparatus further includes a hot air supply device that supplies the hot air to an inside of the case member, wherein the hot air supply device recovers the hot air discharged from the discharge opening to resupply to an inside of the case member.
According to such a bulk recovery apparatus for nonwoven fabrics, some energy can be reused while suppressing an adverse effect on the other proximate semimanufactured products when the hot air is discharged from the case member.
It is preferable that the nonwoven fabric bulk recovery apparatus further includes a CD direction that is a direction orthogonal to each of a vertical direction of the case member and the transfer direction, wherein the discharge of the hot air from the discharge opening and the supply of the hot air to the inside of the case member are performed on a same side with respect to the CD direction of the case member.
According to such a bulk recovery apparatus for nonwoven fabrics, the tube for supplying hot air and the tube for discharging and recovering hot air can be connected on the same side with respect to the CD direction and thus the space for the piping can be reduced. Hereby, the overall size of the bulk recovery apparatus can be minimized.
Further, there will be made clear a method of recovering a bulk of a nonwoven fabric by blowing hot air and heating the nonwoven fabric that is transferred in a transfer direction, including: when an entrance is provided to an opening on one end side in the transfer direction to transfer the nonwoven fabric and an exit is provided to an opening on an other end side in the transfer direction to transfer the nonwoven fabric, in a case member that has both end portions thereof in the transfer direction opened, blasting from a blast opening provided to a part on the entrance side of the case member the hot air toward a part on the exit side and into a space inside the case member; and in the case member having a sectional area, in the space inside the case member, at a first position that is located on a downstream side along the transfer direction with respect to a position where the blast opening is provided, wider than a sectional area, in the space inside the case member, at a second position that is located between the position where the blast opening is located and the first position, allowing the hot air blasted from the blast opening to flow from an upstream side along the transfer direction through the first and the second positions and to the downstream side along the transfer direction while coming into contact with one face of two faces of the nonwoven fabric.
According to such a bulk recovery method for nonwoven fabrics, the flow rate of the hot air can be lowered by expanding the hot air flow path area (sectional area) in a downstream side area along the transport direction. Hereby, the flow rate of the hot air is appropriately adjusted so to restrain the nonwoven fabric from stretching in the transfer direction which in turn allows a normal bulk recovery to be performed.
The bulk recovery apparatus 20 and the bulk recovery method for nonwoven fabric 3 according to the present embodiment aims to processes the nonwoven fabric 3 which becomes the top sheet 3 of the pee pad 1 for pets.
The pee pad 1 is used to catch excrement of animals such as dogs and cats and is used by placing the pee pad 1 on the floor and the like, as illustrated in
As illustrated in
The back sheet 5 is, for example, a film material such as polyethylene (hereinafter, PE), polypropylene (hereinafter, PP), polyethylene terephthalate (hereinafter, PET) and the like. However, it is not limited to such and any liquid permeable sheet may be used.
The top sheet 3 is made of a nonwoven fabric 3 material. In this example, one face 3b of the two faces 3a, 3b of the nonwoven fabric is in an approximately flat plane, but the other face 3a is in a corrugated shape. In other words, linear grooves 3t and linear bumps 3p are formed alternately. These bumps 3p, 3p . . . are formed by having the fibers originally existing at the grooves 3t blown sideways to be raised by a well known air blowing process (see such as Japanese Patent Application Laid-open Publication No. 2009-11179), with the fibers in loose states. And hereby, this nonwoven fabric 3 as a whole is made bulky. Further, a plurality of through holes 3h, 3h . . . penetrating in the thickness direction may be formed to the grooves 3t, as in this example.
The average basis weight of this nonwoven fabric 3 is, for example, 10 to 200 (g/m2), the average basis weight at the center parts of the bumps 3 p is, for example, 15 to 250 (g/m2) and the average basis weight at the bottom portions of the grooves 3t is 3 to 150 (g/m2).
Further, it is preferable that the fiber of the nonwoven fabric 3 is a composite fiber type having a so-called core-sheath structure which is configured of a core and a sheath made of different materials, however, fiber having a side-by-side structure may be used or a single fiber type made of only thermoplastic resin may be used.
Furthermore, the nonwoven fabric 3 may include crimped fiber. Here, crimped fiber is fiber in a crimped form such as a wavy form, a pinched form, a helical form and the like.
And the fiber length of the fibers included in the nonwoven fabric 3 is selected from the range of, for example, 20 to 100 mm and the fineness is selected from the range of, for example, 1.1 to 8.8 (dtex).
The pee pad 1 is manufactured in a pee pad 1 manufacturing line and the nonwoven fabric 3 used as the top sheet 3 is brought into this manufacturing line in a nonwoven fabric roll 3R (
However, as aforementioned, there is a possibility that the bulk of the nonwoven fabric 3 would be flattened when in the nonwoven fabric roll 3R. For such reason, this manufacturing line is provided with a bulk recovery apparatus 20.
As illustrated in
By the way, similar to the bulk recovery apparatus 20, the various devices (not shown) on the manufacturing line are arranged on this line supported by an appropriate support member. And in this example, a so-called faceplate (not shown) is used as an example of this support member. The faceplate is a plate member provided to stand vertically on the floor portion of the manufacturing line and this faceplate includes a vertical plane (a plane whose normal direction faces the horizontal direction) and the various devices are supported by this vertical plane in for example, a cantilevered state.
And in the following description, the direction normal to this vertical plane will be called the “CD direction”. Here in
The transfer portion 30 includes a plurality of transfer rollers 32, 32 . . . which define the transfer path of the nonwoven fabric 3 and a supply device 35.
The transfer rollers 32, 32 . . . are rotatably supported about the rotating shaft which comes along the CD direction and hereby the nonwoven fabric 3 is transferred in a position having the width thereof facing the CD direction. Some of the transfer rollers 32, 32 among the transfer rollers 32, 32 . . . are drive rollers 32u, 32d which are driven to rotate with the servo motor which acts as the drive source. And the other rollers 32, 32 . . . are follower rollers which do not have a drive source in other words, are rollers that are rotated by the rotating force caused by coming into contact with the nonwoven fabric 3 being transferred.
The drive rollers 32u, 32d are provided to the positions on the two sides of the heating portion 60 (specifically, the later described heating unit 61) at the transfer path. And the transfer state of the nonwoven fabric 3 at the heating portion 60 can be adjusted by controlling the rotational movement of the upstream side drive transfer rollers 32u and the downstream side drive transfer rollers 32d.
The supply device 35 is a device which supplies the nonwoven fabric 3 from the nonwoven fabric roll 3R and includes a rotating shaft which is arranged along the CD direction. And the nonwoven fabric roll 3R is rotatably supported by this rotating shaft. The rotating shaft is driven to rotate by, for example, a servo motor (not shown) which serves as the drive source and hereby, the nonwoven fabric 3 is supplied from the nonwoven fabric roll 3R. Here, a plurality e.g. two) of the supply devices 35 may be provided to have a plurality (two) of the nonwoven fabric rolls 3R alternatively used by switching. That is, the configuration may be such that while one of the supply devices 35 is supplying the nonwoven fabric 3, the other supply device 35 is in a waiting state and when the nonwoven fabric roll 3R of the one of the supply devices 35 is used up the supply device 35 in a waiting state may start supplying the nonwoven fabric 3. Note that, the detailed description of this supply device 35 is omitted since the supply device 35 is well known.
Further, an accumulator device and a tension control device (both not shown) may be equipped, to the transfer portion 30, between the supply device 35 and the upstream side drive transfer roller 32u. The accumulator device is a device which deliverably accumulates toward the downstream along the transfer direction the nonwoven fabric 3 supplied by the supply device 35. For example, when one supply device 35 among the two supply devices 35 supplies all the nonwoven fabric 3 from the nonwoven fabric roll 3R and the supply device 35 stops when switching to the other supply device 35, the accumulator device itself delivering the accumulated nonwoven fabric 3 can avoid effects to the downstream caused by stopping the supply by the supply device 35. The tension control device is a device which adjusts to a predetermined target value (N) the tensility (N) of the nonwoven fabric 3 to be transferred.
The heating portion 60 includes a heating unit 61 which while allowing the nonwoven fabric 3 to pass therethrough blows hot air against the nonwoven fabric 3 for heating and a hot air supply device 67 which supplies hot air to this heating unit 61.
The heating unit 61 includes a case member 62 having both end sections along the longitudinal direction opened and a plurality of guide rollers 64, 64, 64 which are provided outside the case member 62 to allow the nonwoven fabric 3 to be guided and reciprocate inside the case member 62. And an outgoing route and a return route of the transfer path of the nonwoven fabric 3 are linearly formed inside the case member 62 by the guide rollers 64, 64, 64. Additionally, as illustrated in
Of the two wall surfaces 63wa, 63wb of the partitioning member 63 the wall surface 63wa (hereinafter, outgoing route wall surface 63wa) which is adjacent to the outgoing route space SP62a, and of the two wall surfaces 63wa, 63wb the wall surface 63wb (hereinafter, return route wall surface 63wb) which is adjacent to the return route space SP62b are respectively arranged parallel to the transfer direction and the CD direction. Hereby, the outgoing route wall surface 63wa and the return route wall surface 63wb are respectively made substantially parallel with the faces of the nonwoven fabric 3. And the upstream side part along the transfer direction of the outgoing route in the outgoing route wall surface 63wa has provided thereto a blast opening 63Na in a slit form long in the CD direction and the upstream side part along the transfer direction of the return route in the return route wall surface 63wb also has provided thereto a blast opening 63Nb in a slit form long in the CD direction. And the blast opening 63Na blasts into the return route space SP62b hot air supplied from the pressure chamber R63a formed inside the partitioning member 63. Similarly, the blast opening 63Nb blasts into the return route space SP62b hot air supplied from the pressure chamber R63a formed inside the partitioning member 63.
At the outgoing route wall surface 63wa, a level differentiated part 63wae is provided to the area along the transport direction downstream with respect to the location where the blast opening 63Na is provided, as illustrated in
Further, an exit portion wall face 63was is provided most downstream along the transfer direction of the level differentiated part 63wae. The 63was is a member which is provided in a manner blocking a part of the exit side space of the outgoing route space SP62a and the outgoing route exit 62aout is formed with this 63was while defining the dimension of the exit 62aout. Additionally, a discharge opening 63ha for discharging to the outside the hot air blasted into the outgoing route space SP62 is provided to the side portion (wall face at the end portion in the CD direction in the outgoing route enlarged area in the case member 62) of the space formed with the level differentiated part 63wae and the exit portion wall face 63was of the outgoing route space SP62a. Here, the area (outgoing route enlarged area) having the sectional area of the space SP62a widened with the level differentiated part 63wae may be provided with a plate-like member 63wam placed along the transfer direction (indicated by dotted lines in
Similarly, at the return route wall surface 63wb, a level differentiated part 63wbe is provided to the area along the transport direction downstream with respect to the location where the blast opening 63Nb is provided and the return route space SP62b has the flow path area widened at a part on the downstream side along the transfer direction. In other words, the sectional area of the return route space SP62b having the transport direction as the normal direction thereof, is wider (return route enlarged area) at the downstream side area along the transport direction than that at the position where the blast opening 63Nbis located. Further, an exit portion wall face 63wbs is provided most downstream along the transfer direction of the level differentiated part 63wbe. The 63wbs is a plate-like member which is provided in a manner blocking a part of the exit side space of the outgoing route space SP62b and the return route exit 62bout is formed with this 63wbs while defining the dimension of the exit 62bout. Additionally, a discharge opening 63hb for discharging to the outside the hot air blasted into the return route space SP62 is provided to the side portion (wall face at the end portion in the CD direction in the return route enlarged area in the case member 62) of the space formed with the level differentiated part 63wbe and the exit portion wall face 63wbs, in the return route space SP62b. Here, the area (return route enlarged area) having the sectional area of the space SP62b widened with the level differentiated part 63wbe may be provided with a plate-like member 63wbm placed along the transfer direction. The 63wbm has a function similar to that of the aforementioned 63wam.
The hot air supply device 67 includes an air blower 67b and a heater 67h. And hot air is generated by heating with the heater 67h wind generated with the air blower 67b, and this hot air is supplied to the pressure chambers R63a, R63b of the partitioning member 63 inside the case member 62 of the aforementioned heating unit 61 through an appropriate tube member 67p. Thereafter, hot air is blasted out from the blast openings 63Na, 63Nb through the pressure chambers R63a, R63b. Here, the hot air is supplied to the pressure chambers R63a, R63b from the end portion side along the CD direction of the case member 62.
The air blower 67b includes, for example, an impeller 67i which is rotated by using a motor as the drive source and an inverter (not shown) which adjusts the rotational speed (rpm) of the aforementioned motor. And hereby, the VVVF inverter control with the controller (not shown) can be performed so that as a result the air volume (m3/min) can be adjusted to any value through changing of the rotational speed (rpm) of the impeller 67i.
Here, as illustrated in
Here, an electric heater which heats using electricity (kW) can be employed as the above heaters 67h, 67ha, 67hb. However, it is not limited to such and any device may do as long as it can heat air which forms wind.
And in this example, the “wind” indicates flows of air but includes in a broad sense, flows of gas such as nitrogen gas and inactive gas besides flows of air. In other words, nitrogen gas and the like may be blown out from the blast openings 63Na, 63Nb.
Further in the present embodiment, each exit portion of the discharge openings 63ha, 63hb has one end sides of the recovery tube member 69 connected and the other end sides of the recovery tube member 69 communicate with the suction side part 67bs of the air blower 67b. Hereby, the hot air flowing through the spaces SP62a, SP62b are recovered to be returned to the suction side part 67bs of the air blower 67b. The recovered hot air is heated with the heater 67h by applying outside air and then supplied again to the heating unit 61. Recovery of the hot air allows reusing of a part of the energy while suppressing negative effects to the other proximate semimanufactured products when the hot air is discharged in the heating unit 61.
In the present embodiment, discharging of the hot air from the discharge openings 63ha, 63hb is performed from the end portion side along the CD direction of the case member 62. Further, discharging of the hot air from the discharge openings 63ha, 63hb is performed on the same side where the hot air is supplied to the pressure chambers R63a, R63b. In other words, in the present embodiment, the hot air is supplied to the heating portion 60 from one end side in the CD direction and the hot air is discharged from the same side. The tube member 67p for supplying hot air and the recovery tube member 69 being connected on the same side with respect to the CD direction allows to reduce the piping space in turn allowing to minimize the device as a whole.
By the way, in cases where the aforementioned plate-like members 63wam, 63wbm are not provided, or where the foreign matters such as the fiber dust of the nonwoven fabric 3 is so small that they would pass through the plate-like members 63wam, 63wbm, there is a possibility that the foreign matters would pass through the recovery tube member 69 and be sent to the heater 67h inside the air blower 67b and bond thereto due to the heat. Therefore, it is preferable that for example, a predetermined meshed filter member for preventing foreign matters to be drawn in is inserted between the suction side part 67bs of the air blower 67b and the recovery tube member 69. It is preferable that a similar kind of filter member is provided to also the suction side part 67bs in the example in
The heating unit 61 in the examples of
Description of the nonwoven fabric 3 bulk recovery operation inside the case member 62 of the heating unit 61 will be given. Here in the present embodiment, the outgoing route space SP62a and the return route space SP62b have substantially the same configuration and the way in which the hot air flows inside the case member 62 and the bulk recovery operation of the nonwoven fabric 3 are also substantially the same. Therefore, description of mainly the outgoing route space SP62a will be given in the following and description of the return route space SP62b may be omitted.
Firstly, the hot air supplied from the hot air supply device 67 is supplied to the pressure chamber R63a provided to the partitioning member 63. The sectional shape (the shape at the section having the normal direction thereof directed in the CD direction) of the pressure chamber R63a is in a tapered shape becoming substantially narrower toward the downstream side of the transfer direction, and the pressure chamber R63a comes into communication with the outgoing route space SP62a at the tip end portion of the tapered shape so to thereby allow the tip end portion function as the aforementioned blast opening 63Na.
The hot air blasted from the outgoing route blast orifice 63Na comes into contact with the surface of the nonwoven fabric 3 with a velocity component of that on the downstream side along the transfer direction, and thereafter flows along this surface as it is (the hot air flow is indicated with thick arrows in
At this event, the wind speed value Vw (m/min) of the hot air can be made greater than the transfer speed value V3 (m/min) of the nonwoven fabric 3 by adjusting the air volume (m3/min) of the hot air. And in this way, the hot air blasted from the blast openings 63Na, 63Nb would pass the nonwoven fabric 3 swiftly along the surface of the nonwoven fabric 3 to be discharged outside from the discharge openings 63ha, 63hb in the end. Therefore, this hot air can easily become turbulent based on the relative speed difference between the hot air and the nonwoven fabric 3. And as a result, the heat-transfer efficiency is dramatically improved so that the nonwoven fabric 3 can be heated efficiently allowing quick bulk recovery. Further, since the fibers of the nonwoven fabric 3 are randomly loosened by the hot air turbulence, this also promotes the bulk recovery.
By the way, the wind speed value Vw (m/min) (hereinafter also referred to as the hot air flow rate) of the hot air is a value obtained by, for example, dividing the air volume (m3/min) supplied to the outgoing route space SP62a or the return route space SP62b by the sectional area (i.e., the area of the section having the transfer direction as the normal direction thereof) of the outgoing route space SP62a or the return route space SP62b.
Further, it is preferable that the magnitude relationship between the aforementioned wind speed value Vw and the transfer speed value V3 is established along the entire transfer direction of the outgoing route space SP62a or the return route space SP62b, however, it need not be established along the entire length thereof. In other words, the functional effect of the aforementioned turbulent state can be relished if the aforementioned magnitude relationship is established at a part of the spaces SP62a, SP62b.
Note that in the present embodiment, some of the surrounding air (exterior of the case member 62) is sucked in to enter into the outgoing route space SP62a when the transferred nonwoven fabric 3 enters from the entrance 62ain into the interior of the case member 62. And the sucked air forms an accompanying flow which flows in the transfer direction by moving along with the transferred nonwoven fabric 3. Since this accompanying flow flows along the transfer direction, the hot air blasted from the blast opening 63Na is likely to flow along the transfer direction so as to be made to flow by this accompanying flow.
Further, the shapes of each of the outgoing route and the return route blast openings 63Na, 63Nb are in rectangular forms having the longitudinal direction directed along the CD direction. And the dimension in the CD direction of the outgoing route blast orifice 63Na is set to have the same value as the dimension along the CD direction of the outgoing route space SP62a and the dimension in the CD direction of the return route blast opening 63Nb is set to have the same value as the dimension in the CD direction of the return route space SP62b, however, it is not limited to such. For example the blast openings 63Na, 63Nb may be smaller. But, it is preferable that the dimensions along the CD direction of the blast openings 63Na, 63Nb are greater than the width dimension (dimension along the CD direction) of the nonwoven fabric 3, and thereby uneven heating along the CD direction can be suppressed.
Additionally, the dimensions (the dimensions along the direction that is orthogonal to the dimensions along the aforementioned CD direction) in the crosswise directions of the blast openings 63Na, 63Nb are arbitrarily selected from the range of, for example, 1 mm to 10 mm, and to be set.
Further, is preferable that the angle θ of the hot air blasting direction with respect to the transfer direction of the nonwoven fabric 3 at the locations of the blast openings 63Na, 63Nb is within the range of 0 to 30 degrees and more preferably within the range of 0 to 10 degrees (see
Here in the example illustrated in
Description has been given that the bulk recovery of the nonwoven fabric 3 can be enhanced by making the hot air be in a turbulent state by increasing the flow rate Vw of the hot air blasted inside the case member 62 in the heating unit 61 to be greater than the transfer speed value V3 of the nonwoven fabric. Meanwhile, there is a case where problems arise when the Vw is too high. Issues arising when the Vw is too high will be described using a comparison example.
By the way, the heating unit 65 of the comparative example continues to have the nonwoven fabric 3 subject to hot air during the process of the nonwoven fabric 3 being transferred inside the case member 62. In other words, the hot air blasted from the blast opening 63Na provided, to the case member 62, at the upstream side in the transfer direction, flows to the downstream side in the transfer direction along the surface of the nonwoven fabric 3 during which the nonwoven fabric 3 is heated. In other words, the nonwoven fabric 3 would have applied heat quantity in an accumulating manner while being transferred from the upstream side to the downstream side along the transfer direction. When such a large heat quantity is applied to the nonwoven fabric 3 in this way, the nonwoven fabric 3 can stretch easily in the transport direction. As explained with respect to
The hot air flowing along the transfer direction along the surface of the nonwoven fabric 3 in the heating unit 65 acts as a tractional force pulling the nonwoven fabric 3 along the transfer direction and thus the nonwoven fabric 3 can be further easily stretched. Particularly, since the hot air flow rate Vw flowing inside the return route space SP62b is substantially stable in the comparative example, the hot air flow rate Vw in the downstream side along the transfer direction would remain high when the hot air flow rate Vw blasted from the blast opening 63Na is high, and so the tractional force pulling the nonwoven fabric 3 in this area would also be large.
When the nonwoven fabric 3 stretches by being pulled in the transfer direction, the bulk at the surface of the part of the nonwoven fabric 3 being stretched would easily flatten so that a sufficient bulk recovery effect would not be achieved. Further, there is a possibility of the nonwoven fabric 3 becoming a non-conforming item which does not satisfy the standard size as a product since the length along the CD direction (i.e., the width of the nonwoven fabric) would shorten along with the stretching of the nonwoven fabric 3 along the transfer direction.
Therefore, in the heating unit 65 with a structure as that in the comparative example, it would be difficult to perform a normal bulk recovery depending on the flow rate of the hot air Vw. Further, there is a possibility that the quality of the product would deteriorate. Thus it would be required to set a limit to the condition (upper speed limit) of the hot air flow rate Vw in the comparative example thereby making it difficult to adapt to various operating conditions.
On the other hand, the heating unit 61 according to the present embodiment can reduce the flow rate Vw in the downstream side area along the transfer direction making it difficult for the nonwoven fabric 3 to be stretched.
As aforementioned, in the present embodiment, the level differentiated part 63wae is provided to the downstream side area of the partitioning member 63 along the transfer direction, and the sectional area of the outgoing route space SP62a is widened in this area (aforementioned enlarged area.) In
In the case of the present embodiment, the hot air flow rate Vwau>Vwad holds since the relation of the sectional area of the outgoing route space SP62a Dau<Dad holds. In other words, the hot air flow rate Vwad at the area on the downstream side along the transfer direction (first position) would be lower than the hot air flow rate Vwau at the area on the upstream side along the transfer direction (second position.) Therefore, the tractional force applied to the nonwoven fabric 3 in the transfer direction due to the flow of the hot air in the enlarged area on the downstream side along the transfer direction will be smaller than that in the comparative example. Hereby, the nonwoven fabric 3 is not stretched easily on the downstream side along the transfer direction where the effect of heating with the hot air is large thereby allowing ease to perform a normal bulk recovery. Further, since the flow rate can be lowered in the enlarged area even when the hot air flow rate blasted from the blast opening 63Na is high, constraints on the hot air flow rate is small.
Further in the heating unit 61 according to the present embodiment, the discharge opening 63ha was provided in the enlarged area of the space SP62a to allow discharge of hot air outside. Hereby, the volume of the hot air can be reduced in the downstream side area along the transfer direction (enlarged area) and thus the hot air flow rate can be lowered in turn allowing the conditions during bulk recovery operation to be easily adjusted.
Furthermore, the discharge opening 63ha is provided to a location shifted vertically from the transfer path of the nonwoven fabric 3. In the example illustrated in
Even furthermore, in the present embodiment, the blast opening 63Na which blasts hot air inside the case member 62 and the discharge opening 63ha which discharges hot air outside from the case member 62 are both provided to locations vertically shifted to the same side with respect to the transfer path of the nonwoven fabric 3. Specifically, in the case illustrated in
Further in the present embodiment, an exit portion wall face 63was was provided at a portion in the space SP62a most downstream along the transfer direction and an exit 62aout of the case member 62 was formed with this exit portion wall face 63was. As is clear from
For example, when the exit portion wall face 63was is not provided to the outgoing route space SP62a of the heating unit 61, the sectional area of the exit 62aout would be about the same as the sectional area (corresponding to the aforementioned sectional area Dad at the first position) of the space SP62a which was widened by the level differentiated part 63wae and would be wider than that in the case in
On the other hand, when the sectional area of the exit 62aout is narrowed as in
Further, since the transfer operation of the nonwoven fabric 3 can be easily stabilized when the direction of the hot air flow and the transfer direction of the nonwoven fabric 3 is made close to parallel as possible, it is preferable that the vertical position of the exit 62aout is made to correspond to the position at the upstream side area along the transfer direction of the space SP62a. In
In the present embodiment, the interior of the case member 62 being configured in the above manner allows appropriate adjustment of the hot air flow in the downstream side area along the transfer direction (enlarged area) at each of the outgoing route space SP62a and the return route space SP62b. Hereby, stretching of the nonwoven fabric 3 in the transfer direction at this area can be suppressed in turn allowing a correct bulk recovery operation to be realized.
Hereinabove, embodiments of the present invention have been described, however, the foregoing embodiments are intended to facilitate the understanding of the present invention but not to limit the invention. And it is needless to say that modifications and improvements of the present invention are possible without departing from the scope of the invention, and equivalents thereof are also encompassed by the invention. For example, the following modifications are possible.
In the aforementioned embodiment, the nonwoven fabric 3 for top sheets 3 of pee pads 1 for pets had been exemplified as the target to be processed by the bulk recovery apparatus 20, however, it is not limited to such. For example, nonwoven fabric for top sheets of sanitary napkins and nonwoven fabric for top sheets of diapers may be the targets. Further, the target to be processed by the bulk recovery apparatus 20 is not at all limited to nonwoven fabric 3 for the top sheet 3. In other words, nonwoven fabric of materials of other components which require to be bulky may processed with the bulk recovery apparatus 20 according to the present invention.
In the aforementioned embodiment, as illustrated in
In the aforementioned embodiment, as illustrated in
In the aforementioned embodiment, a solid member which does not include space inside besides the pressure chambers R63a, R63b and the enlarged areas formed with the level differentiated parts 63wae, 63wbe had been used as the material of the partitioning member 63, however, it is not limited to such. For example, hollow members including a space inside may be used for the purposed of weight reduction. For example, a member made of a combination of a stainless steel flat plate member (not shown) which forms the outgoing route wall surface 63wa in
In the aforementioned embodiment, the spaces SP62a, SP62b were expanded in the vertical direction with the level differentiated parts 63wae, 63wbe, however, the way in which the spaces SP62a, SP62b are expanded are not limited to such. For example, the spaces SP62a, SP62b may be expanded in the CD direction in the downstream side area along the transfer direction. Since the hot air flow rate can be minimized in this area even when the spaces SP62a, SP62b are expanded in the CD direction, the stretching of the nonwoven fabric 3 in the transfer direction can be suppressed to allow a normal bulk recovery operation.
Further in the aforementioned embodiment, when the sectional areas of the spaces SP62a, SP62b were expanded with the level differentiated parts 63wae, 63wbe, the sectional forms along the transfer direction in the spaces SP62a, SP62b were expanded in a stepwise manner as illustrated in
| Number | Date | Country | Kind |
|---|---|---|---|
| 2013-217194 | Oct 2013 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2014/076719 | 10/6/2014 | WO | 00 |
