JP2008110569A - Manufacturing method of honeycomb structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stabilize the shape of a honeycomb molding, in a process of drying a molding having been formed and dry the honeycomb moldings. <P>SOLUTION: First, a columnar workpiece 30 with numerous holes is formed and then the workpiece 30 is dried in a drying process. In this case, a plurality of end discs 10, each being made up of a porous board member with a fluororesin tape 20 attached to one edge face 12 of the board member, are prepared. After that, both edge faces of the workpiece 30 are inserted between the end discs 10. In this state, each edge face of the workpiece 30 and the fluororesin tape 20 of each end disc 10 are made to face each other. Finally, the workpiece 30 is placed on the end disc 10 and the other end disc is placed on the workpiece 30 and then the workpiece 30 is dried with the end discs 10 in a piggyback style. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a honeycomb structure, and more particularly to a drying process in which a workpiece (honeycomb formed body) shaped like a honeycomb structure is formed and then dried.

  Conventionally, a method for manufacturing a ceramic honeycomb structure has been proposed in Patent Document 1, for example. In Patent Document 1, an extrusion process for forming a columnar honeycomb formed body from a ceramic material obtained by kneading raw material powder and water, a cutting process for cutting the honeycomb formed body into a certain length, and the cut honeycomb formed body There has been proposed a method of manufacturing a ceramic honeycomb structure in which a drying step of drying the ceramic is sequentially performed.

In the drying step among the above steps, first, a porous transport tray is prepared, and the honeycomb formed body is placed on the transport tray so that the holes of the transport tray and the pores of the honeycomb formed body are in communication with each other. Next, the transport tray is carried into a drying apparatus, and the honeycomb formed body is dielectrically heated with microwaves in a high-temperature, high-humidity atmosphere. In this way, the honeycomb formed body is dried.
JP 2002-283331 A

  However, in the above conventional technique, when the drying process is performed in a state where the honeycomb formed body is placed on the transport tray, the following problems occur. That is, the honeycomb formed body heated in the drying apparatus expands first and then contracts. As described above, when the honeycomb formed body thermally expands or contracts, the outer peripheral portion of the end face of the honeycomb formed body is caught by the lattice constituting the porous structure of the transfer tray at the contact surface between the honeycomb formed body and the transfer tray. End up.

  That is, when heating is continued, the heat shrinkage change on the side of the honeycomb molded body that contacts the transport tray is hindered by the transport tray, but the heat shrinkage of the side that does not contact the transport tray is not prevented. As a result, the diameter of the honeycomb molded body on the side in contact with the transport tray is larger than the diameter on the non-contacted side, resulting in variations in the shape of the honeycomb molded body.

  In view of the above points, an object of the present invention is to stabilize the shape of a honeycomb formed body in a step of drying the formed honeycomb body and drying it.

  In order to achieve the above object, according to the first feature of the present invention, a columnar workpiece (30) provided with a large number of holes (4) is formed in a molding step, and the workpiece (30) is formed in a drying step. In drying, in the drying step, first, a drying plate member (10) which is a porous plate member and is provided with a sheet member (20) on one end surface (12) of the plate member is prepared. Thereafter, the workpiece (30) is placed on the end surface (12) provided with the sheet member (20) in the drying plate member (10) so that the end surface of the workpiece (30) and the sheet member (20) face each other. The workpiece (30) is dried in a wet state.

  Thus, when the workpiece (30) is thermally deformed by drying the workpiece (30) by providing the sheet member (20) on the drying plate member (10), the workpiece (30) and the drying plate are dried. Restraint force against thermal change of the work (30) at the contact surface with the plate member (10), particularly the contact surface between the outer peripheral portion of the end surface of the work (30) and the porous surface of the drying plate member (10). Can be reduced. That is, the resistance that the workpiece (30) receives on the porous surface of the drying plate member (10) can be reduced. Thereby, the dimensional dispersion | variation of the both ends of a workpiece | work (30) can be reduced, and by extension, the shape of the workpiece | work (30) after drying can be stabilized.

  Further, a plurality of drying plate members (10) provided with the sheet member (20) are prepared, and both end surfaces of the work (30) are sandwiched between the drying plate members (10). At this time, both end surfaces of the work (30) and the sheet member (20) of each drying plate member (10) are made to face each other. Then, the workpiece (30) can be dried with the workpiece (30) placed on the drying plate member (10) and the drying plate member (10) placed on the workpiece (30).

  Thereby, the conditions of the force to the plate member for drying (10) applied to both ends of the workpiece (30) during drying can be made the same. Therefore, the dimensional difference between both ends of the work (30) can be reduced, and the shape of the work (30) after drying can be stabilized.

  Furthermore, as the sheet member (20), it is preferable to use a fluororesin tape in which one surface is a sliding surface on which the outer peripheral portion of the end surface of the work (30) is rubbed. The sliding surface of such a fluororesin tape is easy to slide, and the resistance applied to the outer peripheral portion of the end surface of the work (30) can be reduced. For example, when the work (30) is heated and dried by microwaves, the fluororesin tape does not generate heat by the microwaves, and thus is suitable for a drying method using such a method.

  And when using the thing by which each porous hole (11) was provided in the grid | lattice form as a board member for drying (10), a sheet | seat member (20) is provided according to the direction of the grid | lattice of each hole (11). Is preferred.

  That is, when the outer peripheral portion of the end surface of the work (30) is deformed along the direction of the lattice of each porous hole (11), the binding force by the drying plate member (10) is most exerted on the outer peripheral portion of the end surface of the work. For this reason, this restraining force can be reduced by providing the sheet member (20) along the direction of the lattice.

  As described above, when each porous hole (11) has a lattice shape, the sheet member (20) is preferably provided in a cross shape along the direction of the lattice of each hole (11).

  Thus, by providing the sheet member (20) in a cross shape, moisture contained in the workpiece (30) can be released through the porous holes (11) of the drying plate member (10). Moreover, the restraining force concerning the outer peripheral part of the end surface of a workpiece | work (30) can also be relieve | moderated.

  In addition, the code | symbol in the bracket | parenthesis of each said means shows the correspondence with the specific means as described in embodiment mentioned later.

(First embodiment)
In the present embodiment, an exhaust gas purification filter will be described as a honeycomb structure. This exhaust gas purification filter (so-called DPF) is used, for example, to purify pollutants contained in exhaust gas discharged from an engine of a vehicle and discharge it to the atmosphere.

  FIG. 1 is a perspective view of an exhaust gas purification filter according to an embodiment of the present invention. As shown in this figure, the exhaust gas purification filter 1 has a cylindrical shape, for example, a ceramic sintered product.

  Moreover, the inside of the exhaust gas purification filter 1 has a honeycomb structure (hereinafter referred to as a honeycomb structure), and has a large number of holes 4 penetrating both end faces 2 and 3 in the axial direction of the cylinder. Each hole 4 is adjacent to each other via a wall 5 separating each hole 4, and each hole 4 is arranged in a direction perpendicular to the axis of the cylinder to form an independent passage. . In other words, a large number of holes 4 are formed by the walls 5 having a lattice shape. In this way, a honeycomb structure is configured.

  Then, on one end face 2 of the exhaust gas purification filter 1, a plug material 6 for plugging the opening of each hole 4 is provided in a part of each hole 4. In the present embodiment, the plug members 6 are provided in a staggered manner in the holes 4. That is, the hole 4 adjacent to the hole 4 provided with the plug material 6 is in a state where the plug material 6 is not provided and is open.

  Furthermore, the plugs 6 are also provided in a staggered manner in a part of each hole 4 of the other end surface 3 of the exhaust gas purification filter 1, as in the case of the one end surface 2. In this case, the plugs 6 plugged in the holes 4 of the end surface 3 in a staggered manner are provided in a staggered pattern in the openings of the holes 4 that are not plugged on the end surface 2 side. The above is the configuration of the exhaust gas purification filter 1 according to the present embodiment.

  The exhaust gas passing through such an exhaust gas purification filter 1 is first guided from one end face 2 of the exhaust gas purification filter 1 into the hole 4 opened in each hole 4. Then, the exhaust gas travels through the passage in the hole 4 toward the end face 3 side, and passes through the wall 5 that separates the hole 4 from the adjacent hole 4. Thereby, the contaminant contained in the exhaust gas is removed inside the wall 5. The exhaust gas is discharged from the other end face 3 of the exhaust gas purification filter 1 through a passage in the hole 4 adjacent to the hole 4 that has entered the exhaust gas purification filter 1. In this way, the pollutant contained in the exhaust gas is removed by the exhaust gas purification filter 1.

  Next, a method for manufacturing the exhaust gas purification filter 1 will be described. First, an extrusion process for forming a honeycomb formed body made of cordierite is performed. Then, the cutting process which cut | disconnects the said honeycomb molded object to fixed length is performed, and the honeycomb molded object which modeled the exhaust gas purification filter 1 is obtained. Hereinafter, the honeycomb formed body divided individually by the cutting process is referred to as a workpiece.

  And the drying process which dries the workpiece | work obtained as mentioned above is performed, and the water | moisture content of a workpiece | work is removed. When performing the said drying process, in this embodiment, a workpiece | work is pinched | interposed with a torch and a workpiece | work is dried with a drying apparatus.

  FIG. 2 is an end view of a torch used in the drying process of the present embodiment, and is a view showing a surface on which a workpiece is brought into contact. As shown in this figure, the end face 12 of the torch 10 (corresponding to the drying plate member of the present invention) has a circular shape, and the torch 10 has a cylindrical structure. In the present embodiment, a torch 10 having a diameter of 190 mm and a thickness of 20 mm is employed.

  The torch 10 is formed of, for example, cordierite, which is the same material as the workpiece, and is a porous plate member in which a large number of holes 11 are provided in the end face 12 so as not to retain moisture. In the present embodiment, as will be described in detail later, since the workpiece is dried by the microwave, the torch 10 that does not generate heat by the microwave is preferable. Further, from the viewpoint of ease of use and reuse, it is preferable that the torch 10 is strong or lightweight.

  Furthermore, a fluororesin tape 20 (corresponding to a sheet member of the present invention) having a width of 15 mm to 20 mm is attached to the end surface 12 of the torch 10. One surface of the fluororesin tape 20 is an adhesive surface, and the other surface is a sliding surface on which the outer peripheral portion of the end surface of the workpiece is rubbed. And the adhesion surface of the fluororesin tape 20 is affixed on the end surface 12 of the torch 10, and a workpiece | work will be mounted on a sliding surface.

  In the present embodiment, the fluororesin tape 20 is affixed to the end face 12 of the torch 10 so as to follow the direction of the lattice that forms each hole 11 of the torch 10. That is, as shown in FIG. 2, the fluororesin tape 20 is attached to the end surface 12 of the torch 10 in a cross shape passing through the center of the end surface 12.

  That is, when the outer peripheral portion of the end surface of the workpiece (specifically, the tangent to the outer peripheral portion) and the orientation of the lattice forming each hole 11 of the torch 10 are parallel, when the workpiece is thermally deformed, the most force is exerted on the outer peripheral portion of the end surface of the workpiece. It takes. For this reason, when the work is thermally deformed, the fluororesin tape 20 is made of a lattice forming each hole 11 of the torch 10 so that the friction between the outer peripheral portion of the work end face and the sliding surface of the fluororesin tape 20 is minimized. It is pasted along the direction.

  In addition, when the width | variety of the fluororesin tape 20 is large, the water | moisture content contained in the workpiece | work may accumulate on the sliding surface of the fluororesin tape 20, and may melt | dissolve a workpiece | work. Moreover, since each hole 11 to which the fluororesin tape 20 is stretched is closed, the passage of moisture in the work at the portion located on the fluororesin tape 20 is reduced. For this reason, it is preferable that the width | variety of the fluororesin tape 20 is about 15 mm-20 mm as mentioned above.

  FIG. 3 is a view showing a state in which both end faces of the work are sandwiched between the tows 10 shown in FIG. As shown in this figure, two tochis 10 shown in FIG. 2 are prepared for one work 30. Then, the end surface 12 on which the fluororesin tape 20 is attached in each torch 10 is disposed so as to face each end surface of the workpiece 30, and the workpiece 30 is sandwiched between the torch 10. As a result, both end faces of the work 30 come into contact with the fluororesin tape 20 in the torch 10.

  When the work 30 is sandwiched between the torch 10 in this manner, it is preferable that each hole 4 of the work and each hole 11 of the torch 10 are communicated with each other. That is, as shown in FIG. 3, since the work 30 is sandwiched between the tows 10, the moisture contained in the work 30 tends to stay in the work 30 itself. Therefore, by communicating each hole 4 of the work and each hole 11 of the torch 10, the water contained in the work 30 is easily evaporated to the outside through each hole 11 of the torch 10.

  In this embodiment, the dimensions of the workpiece 30 are, for example, a diameter of 160 mm and a height of 180 mm. Therefore, each end surface of the work 30 is prevented from being detached from the end surface 12 of the torch 10.

  In this step, the work 30 is dried using a drying device. 4A and 4B are schematic views of the drying device, where FIG. 4A is a top view and FIG. 4B is a front view. As shown in FIG. 4, the drying device 40 includes a drying chamber 41, a rotary table 42, a microwave irradiation port 43, and a vapor injection port 44.

  The drying room 41 is a room into which the work 30 shown in FIG. 3 is carried. When the drying process is performed, the drying chamber 41 is a closed space. The rotary table 42 is a table on which the work 30 sandwiched between the tows 10 is installed, and rotates in the direction shown in FIG. 4A while the work 30 is being dried.

  The microwave irradiation ports 43 are irradiation ports that irradiate the drying chamber 41 with microwaves, and a plurality of the microwave irradiation ports 43 are provided in the drying chamber 41. In the present embodiment, microwaves having a frequency of 1000 to 10000 MHz generated by a microwave generator (not shown) are irradiated into the drying chamber 41 from a microwave irradiation port 43 shown in FIG. 4 via a waveguide (not shown). Is done. In the present embodiment, the microwave irradiation port 43 is disposed in the upper part of the drying chamber 41 so that the microwave is irradiated to the rotary table 42 side.

  In the present embodiment, as shown in FIG. 4A, the microwave irradiation port 43 is attached to the side surface of the drying chamber 41 other than the operator side.

  The steam injection port 44 is an injection port that injects steam into the drying chamber 41 in order to adjust the humidity in the drying chamber 41. In the present embodiment, for example, steam of 80 ° C. or higher generated by a humidifier (not shown) is injected into the drying chamber 41 from a steam injection port 44 shown in FIG. 4 via a steam pipe (not shown). Thereby, the drying chamber 41 becomes a high humidity atmosphere of 70% or more, for example.

  Thus, by making the drying chamber 41 into a high-temperature and high-humidity atmosphere, when the workpiece 30 is heated, it is possible to prevent rapid drying such that the outer peripheral surface of the workpiece 30 is deformed. Thereby, the difference in the drying speed between the outer peripheral surface of the work 30 and the inside can be reduced.

  The drying device 40 having the above configuration is controlled by a control device (not shown) configured as a personal computer including a CPU, RAM, ROM, hard disk, and the like.

  And the workpiece | work 30 pinched | interposed with the torch 10 is carried in in the drying chamber 41 of the drying apparatus 40 shown by FIG. That is, the workpiece 30 is placed on the torch 10 and the torch 10 is placed on the workpiece 30. Subsequently, the drying chamber 41 is sealed, the rotary table 42 is rotated, and the workpiece 30 is heated by irradiating the workpiece 30 with microwaves from the microwave irradiation port 43 while ejecting steam from the vapor ejection port 44.

  In the present embodiment, two workpieces 30 are carried into the drying chamber 41 of the drying device 40. Note that the number of workpieces 30 carried into the drying chamber 41 is not two, but may be three or four. That is, the time for heating the workpieces 30 may be adjusted according to the number of workpieces 30 carried into the drying chamber 41.

  At this time, the workpiece 30 is initially thermally expanded and then thermally contracted. However, since the fluororesin tape 20 is attached to the torch 10, each outer peripheral portion of each end surface of the workpiece 30 has a hole 11 in each torch 10. The thermal expansion and contraction occur while sliding on the sliding surface of the fluororesin tape 20 without being caught by the formed lattice. As described above, when the workpiece 30 is thermally deformed when the workpiece 30 is dried, the contact surface between the workpiece 30 and the torch 10, particularly the contact surface between the outer peripheral portion of the end surface of the workpiece 30 and the porous surface of the torch 10. The restraining force with respect to the thermal change of the workpiece 30 can be reduced. That is, the resistance that the workpiece 30 receives on the porous surface of the torch 10 can be reduced. Thereby, the dimensional variation of the both ends of the workpiece | work 30 can be reduced, and the shape variation of the workpiece | work 30 can be reduced in the said drying process.

  Thereafter, the work 30 is taken out from the drying chamber 41. Thus, the drying process ends. As described above, the work 30 is dried by heating the work 30 to such an extent that the work is not completely fired. In addition, after the said drying process is complete | finished, the torch 10 can be left in air | atmosphere, it can return to normal temperature, it can dry naturally, and can be reused.

  Thereafter, a masking step of attaching a mask tape (not shown) to both end faces of the work 30 is performed. In this step, for example, a polyester-based adhesive sheet is used as the mask tape.

  Subsequently, a hole making process for making holes in the mask tape is performed. That is, in order to plug the both end surfaces 2 and 3 of the exhaust gas purification filter 1 as described above, the mask tape attached to each of the both end surfaces of the work 30 is irradiated with laser light, and the mask tapes are formed in a staggered pattern. Open it.

  In this step, for example, a method is adopted in which both end surfaces of the workpiece 30 are photographed with a camera, and a hole to be drilled in the mask tape is calculated and then drilled with a laser. However, perforation of each mask tape on both end faces of the work 30 is performed so that the staggered pattern is shifted by four holes on both end faces.

  Next, a plugging process is performed in which a plug material 6 is provided at the opening of each hole 4 drilled in the mask tape. In this process, both end surfaces of the work 30 are immersed in the ceramic liquid, and the ceramic liquid is introduced into the holes 4 where the mask tape is perforated so as to be plugged. And the plug material 6 is formed by heating the both end surfaces of the workpiece | work 30 by which plugging was made.

  Thereafter, the workpiece 30 is placed on a carriage, the carriage is carried into a firing furnace, and a firing process is performed in which the workpiece 30 is fired. Specifically, the carriage on which the workpiece 30 is mounted is carried into a firing furnace, and each workpiece 30 is heated at, for example, 1500 ° C. in the firing furnace. Thereafter, the carriage is taken out from the firing furnace. Thereby, the exhaust gas purification filter 1 shown in FIG. 1 is completed.

  As described above, in this embodiment, two tochis 10 each having the fluororesin tape 20 attached to the end surface 12 are prepared, and the workpiece 30 is attached to the end surface 12 to which the fluororesin tape 20 is attached in each torch 10. It is characterized in that the work 30 is sandwiched and dried. Thereby, even if the workpiece 30 is heated and thermally expanded or contracted in the drying process, the outer periphery of the end surface of the workpiece 30 slides on the sliding surface of the fluororesin tape 20, and thus each hole 11 of the end surface 12 of the torch 10. It is possible not to get caught in the lattice forming That is, it is possible to make the work 30 slip easily on the fluororesin tape 20.

  In this way, by reducing the frictional force of the work 30 on the end face 12 of the torch 10, the shape change due to thermal expansion and heat shrinkage at both ends of the work 30 can be made the same condition, and the difference in shape change is reduced. be able to. As described above, the variation in the shape of each workpiece 30 can be reduced, and as a result, the shape of each workpiece 30 after drying can be stabilized.

(Other embodiments)
In the above embodiment, the columnar exhaust gas purification filter 1 has been described. However, the exhaust gas purification filter 1 is not limited to a columnar shape, and may have another column shape such as a prism. Moreover, even when manufacturing a monolith in which the plug material 6 is not provided in the honeycomb structure, the above method can be employed. Similarly, the torch 10 is not limited to a cylindrical shape, and may have another column shape.

  In the above embodiment, the workpiece 30 is dried using microwaves, but the method is not limited to this method, and a method of drying the workpiece 30 by heating the workpiece 30 may be adopted.

  In the above embodiment, the torch 10 is arranged on both end faces of the work 30, but when the work 30 is placed on the turntable 42, the torch 10 is arranged at least between the turntable 42 of the drying device 40 and the work 30. good. In this case, the work 30 can be dried in a state where the work 30 is placed on the torch 10 so that the end face of the work 30 and the fluororesin tape 20 face each other on the end face 12 provided with the fluororesin tape 20 in the torch 10. It ’s fine.

  Thereby, at least the outer peripheral portion of the end surface of the work 30 on the rotary table 42 side is not caught in each hole 11 of the torch 10 by the fluororesin tape 20 provided on the torch 10, and the both ends of the work 30 are not dried. Variations in shape can be suppressed. However, since the microwave is directly irradiated to the end surface of the workpiece 30 where the torch 10 is not provided, there is a possibility that the workpiece 30 may become hot and melt. Preferably, as in the first embodiment, it is desirable to arrange the torch 10 on both end faces of the work 30.

  In the above embodiment, the fluororesin tape 20 is affixed to the end surface 12 of the torch 10 in a cross shape, but other tensioning methods may be used. For example, the fluororesin tape 20 can be affixed at every fixed angle. Moreover, although the fluorine-type thing is used as the fluororesin tape 20, you may use the resin tape of another material.

  In the said embodiment, although the tape-shaped thing is used as the fluororesin tape 20, it may be a sheet-like thing, ie, what makes another shape irrespective of a tape shape. For example, in the first embodiment, two fluororesin tapes 20 are affixed to the end surface 12 of the torch 10 in a cross shape, but a sheet-like material cut into a cross shape is the end surface of the torch 10. 12 may be attached. Of course, it is not limited to the cross shape, and the fluororesin tape 20 having a desired shape can be cut out from a single sheet.

1 is a perspective view of an exhaust gas purification filter according to an embodiment of the present invention. It is the figure which showed the end surface of the torch used at the drying process of this embodiment. It is the figure which showed a mode that the both end surfaces of a workpiece | work are pinched | interposed with the torch shown by FIG. It is the schematic of the drying apparatus used at a drying process, (a) is a top view, (b) is a front view.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Exhaust gas purification filter, 2, 3 ... Both ends of exhaust gas purification filter, 4 ... Hole, 10 ... Torch, 11 ... Torch hole, 12 ... End surface of torch, 20 ... Fluorine resin tape, 30 ... Workpiece, 40 ... Drying apparatus.

Claims (5)

A method for manufacturing a honeycomb structure having a pillar shape and having a plurality of holes (4) penetrating both end faces (2, 3) of the pillar shape in an axial direction of the pillar shape,
A molding step of molding a columnar workpiece (30) provided with the plurality of holes (4);
A drying step of drying the workpiece (30),
In the drying step,
A step of preparing a plate member for drying (10) which is a porous plate member and provided with a sheet member (20) on one end face (12) of the plate member;
The workpiece (30) so that the end surface of the workpiece (30) and the sheet member (20) face each other on the end surface (12) provided with the sheet member (20) of the drying plate member (10). And a step of drying the workpiece (30) in a state where the substrate is placed. A method for manufacturing a honeycomb structure, comprising: In the step of preparing the drying plate member (10), a plurality of the drying plate members (10) provided with the sheet member (20) are prepared,
In the step of drying the workpiece using the drying plate member (10), both the end surfaces of the workpiece (30) and the sheet members (20) of the drying plate members (10) are respectively used. The workpiece (30) is placed on the drying plate member (10) by being sandwiched between the drying plate members (10) so as to face each other, and further, the drying plate member (10 The method for manufacturing a honeycomb structured body according to claim 1, wherein the work (30) is dried in a state where the material is placed. In the step of preparing the drying plate member (10), as the sheet member (20), a fluororesin tape whose one surface is a sliding surface on which the outer peripheral portion of the end surface of the workpiece (30) is rubbed is used. The method for manufacturing a honeycomb structured body according to claim 1 or 2, wherein the honeycomb structured body is manufactured. In the step of preparing the drying plate member (10), the drying plate member (10) is prepared by providing each porous hole (11) in a lattice shape, and the sheet member (20) is prepared. The method for manufacturing a honeycomb structured body according to any one of claims 1 to 3, wherein the honeycomb structure is provided in accordance with a lattice direction of each of the holes (11). In the step of preparing the drying plate member (10), when the porous holes (11) are in a lattice shape, the sheet member (20) is oriented in the lattice direction of the holes (11). The method for manufacturing a honeycomb structured body according to claim 4, wherein the honeycomb structure is provided in a cross shape.

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