Abstract:
The present invention relates to a tape heater including: at least one flexible fabric base formed from a heat-resistant thread, the at least one flexible fabric base including a first fabric base part and a second fabric base part; and a heater member, in which the heater member is interposed between the first fabric base part and the second fabric base pan. Since the heater member is interposed between the fabric base(s), the tape heater of the present invention exhibits superior flexibility and stretchability and is superior in easily being wrapped around a pipe, as well as reliably protecting the heater member. Further, tape heaters can be continually manufactured, so long as weaving or knitting of the fabric base(s) is caused to proceed while the heater member is interposed between the fabric base(s), to thus join the fabric base(s). Hence, enhancement of production efficiency and prevention of an increase in production cost can be attained.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to a tape heater and a method for manufacturing the tape heater. 
       BACKGROUND OF THE INVENTION 
       [0002]    A tape heater has hitherto been used while being wrapped around a pipe, or the like, in order to heat or thermally insulate the pipe in a wrapped fashion for preventing freezing of the pipe or to hinder generation of byproducts, which would otherwise be caused as a result of cooling of exhaust gases emitted in various processes of manufacturing a semiconductor, in the semiconductor industry (see; for instance, JP-A-2004-303580 and JP-A-63-24582). 
         [0003]    In the tape heater described in JP-A-2004-303580, a heating wire is disposed on a heat-resistant, strip-shaped flexible base material having electrical insulation and is stitched at predetermined intervals, to thus become fastened. Subsequently, the entirety of the heating wire is wrapped with a heat-resistant resin sheet. 
         [0004]    In a tape heater described in JP-A-63-24582, carbon fibers coated with an electrically-insulative synthetic resin are taken as heating elements, and the heating elements are woven along with ordinary fibers into a strip shape. 
       SUMMARY OF THE INVENTION 
       [0005]    However, in the tape heater described in JP-A-2004-303580, after the heating wire has been fastened onto the base material, since the entirety of the heating wire is wrapped with a heat-resistant resin sheet, the heater cannot be manufactured continually, to thus result in poor productivity. 
         [0006]    In the tape heater described in JP-A-63-24582, the heating elements are woven along with other fibers, and hence the heater can be manufactured continually, which leads to superior productivity. However, the heating elements are exposed through an exterior surface of the tape heater. Therefore, there is a concern that, if damage is inflicted on the tape heater, electrical insulation will be lost, thereby inducing shorts. 
         [0007]    The present invention has been conceived in light of such drawbacks and aims at continually manufacturing a tape heater that reliably protects a heating member, that exhibits superior flexibility, stretch properties, and that is superior in easily being wrapped around a pipe. 
         [0008]    In order to achieve the object, the present invention provides tape the following heaters and methods for manufacturing the heaters. 
         [0009]    (1) A tape heater comprising: 
         [0010]    at least one flexible fabric base formed from a heat-resistant thread, the at least one flexible fabric base comprising a first fabric base part and a second fabric base part; and 
         [0011]    a heater member, 
         [0012]    wherein the heater member is interposed between the first fabric base part and the second fabric base part. 
         [0013]    (2) A tape heater comprising: 
         [0014]    a flexible fabric base formed by weaving a heat-resistant thread; and 
         [0015]    a heater member, 
         [0016]    wherein the heater member is disposed in the fabric base. 
         [0017]    (3) The tape heater according to (1), wherein the fabric base is woven or knitted tubular fabric. 
         [0018]    (4) The tape heater according to (1), wherein the thread comprises heat-resistant inorganic fibers. 
         [0019]    (5) The tape heater according to (2), wherein the thread comprises heat-resistant inorganic fibers. 
         [0020]    (6) The tape heater according to (1), wherein the heater member is formed by sheathing a heating wire with an electrically-insulative sleeve. 
         [0021]    (7) The tape heater according to (2), wherein the heater member is formed by sheathing a heating wire with an electrically-insulative sleeve. 
         [0022]    (8) A method for manufacturing a tape heater comprising: 
         [0023]    a step of forming at least one flexible fabric base by knitting or weaving a heat-resistant thread, the at least one flexible fabric base comprising a first fabric base part and a second fabric base part; 
         [0024]    a step of interposing a heater member between the first fabric base part and the second base part; and 
         [0025]    a step of joining the fabric base(s). 
         [0026]    (9) A method for manufacturing a tape heater comprising: 
         [0027]    a step of forming a flexible fabric base while weaving a heat-resistant thread and internally wrapping a heater member. 
         [0028]    (10) The method for manufacturing a tape heater according to (8), the fabric base is woven or knitted tubular fabric. 
         [0029]    (11) The method for manufacturing a tape heater according to (8), wherein knitting or weaving of the fabric base(s) is caused to proceed while the heater member is disposed, by continuously performing each of the steps. 
         [0030]    (12) The method for manufacturing a tape heater according to (10), wherein knitting or weaving of the fabric base is caused to proceed while the heater member is disposed, by continuously performing each of the steps. 
         [0031]    Since the heater member is interposed between the first fabric base part and the second fabric base part, the tape heater of the present invention exhibits superior flexibility and stretchability and is superior in easily being wrapped around a pipe, as well as reliably protecting the heater member. Further, tape heaters can be continually manufactured, so long as weaving or knitting of the fabric base(s) is caused to proceed while the heater member is interposed between the fabric base(s), to thus join the fabric base(s). Hence, enhancement of production efficiency and prevention of an increase in production cost can be attained. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0032]      FIG. 1A  is a plan view showing a first embodiment of a tape heater of the present invention, and  FIG. 1B  is a cross-sectional view taken along line A-A in  FIG. 1A ; 
           [0033]      FIG. 2A  is a cross-sectional view of the tape heater shown in  FIG. 1  taken along line B-B,  FIG. 2B  is a plan view achieved in direction B shown in  FIG. 2A , and  FIG. 2C  is a plan view achieved in direction C in  FIG. 2A ; 
           [0034]      FIG. 3  is a schematic view showing an apparatus for manufacturing the tape heater of the first embodiment; 
           [0035]      FIG. 4  is a plan view showing a tape heater precursor produced by the apparatus shown in  FIG. 3 ; 
           [0036]      FIG. 5  is a cross-sectional view showing a second embodiment of the tape heater of the present invention as in  FIG. 1B ; 
           [0037]      FIG. 6  is a schematic view showing an apparatus for manufacturing the tape heater of the second embodiment; 
           [0038]      FIG. 7  is a cross-sectional view showing a third embodiment of the tape heater of the present invention as in  FIG. 1B ; 
           [0039]      FIG. 8  is a schematic view showing an apparatus for manufacturing the tape heater of the third embodiment; 
           [0040]      FIG. 9  is a cross-sectional view showing a tape heater of a fourth embodiment; 
           [0041]      FIGS. 10A and 10B  are cross-sectional views showing a tape heater of a fifth embodiment; and 
           [0042]      FIG. 11  is a schematic view for describing another method for manufacturing a tape heater of the present invention. 
       
    
    
     DESCRIPTION OF REFERENCE NUMERALS AND SIGNS 
       [0000]    
       
         
           
               10 ,  10 B,  10 C,  10 D and  10 E TAPE HEATERS 
               10 A and  10 A′ TAPE HEATER PRECURSORS 
               11 B DOUBLE-WIDTH FABRIC BASE 
               11 C TUBULAR FABRIC BASE 
               11   a  FIRST FABRIC BASE PART 
               11   b  SECOND FABRIC BASE PART 
               12 ,  12 A and  12 B HEATER MEMBERS 
               13  THREAD 
           
         
       
     
       DETAILED DESCRIPTION OF THE INVENTION 
       [0051]    Embodiments of the present invention will be described hereunder in detail by reference to the drawings. 
       First Embodiment 
       [0052]      FIG. 1A  is a plan view showing a first embodiment of a tape heater of the present invention, and  FIG. 1B  is a cross-sectional view taken along line A-A shown in  FIG. 1A . 
         [0053]    As illustrated, the tape heater  10  of the present embodiment of the present invention has a fabric base  11  including long lengths of first and second fabric base parts  11   a  and  11   b  made of a heat-resistant thread  13  and a heater member  12  sandwiched between the first and second fabric base parts  11   a  and  11   b . Both brims of the first and second fabric base parts  11   a  and  11   b  having the heater member  12  sandwiched therebetween and areas between the brims are stitched at predetermined intervals along a longitudinal direction of the tape heater (see reference symbol L 1  in  FIG. 1B ), thereby joining the fabric bases. Contacting of portions of the heater member  12 , which would otherwise be caused by movement of the heater member in a widthwise direction, is prevented by stitching. Further, lead wires  14  and  14  to be connected to an external power source are drawn from end parts of the heater member  12 . The fabric base parts  11   a  and  11   b  can also be formed by knitting operation of a conventional knitting machine or weaving operation of a conventional weaving machine. 
         [0054]    In addition to having a heat resistance, glass fiber is easy to weave, has high strength, is inexpensively available in the market, and does not contain any volatile constituents; hence, the glass fiber is preferable for the thread  13 . However, the thread can also be formed from heat-resistant inorganic fiber, such as ceramic fiber, silica fiber, and alumina fiber, or a heat-resistant resin, such as a fluorine resin. It is particularly important for a semiconductor manufacturing system that the thread does not contain volatile constituents responsible for outgassed contamination. A weaving pattern is not restricted to any particular pattern, and any pattern, such as a plain weaving pattern or a twill weaving pattern, is available. Moreover, a width W 1  of the fabric base  11  is not restricted to any limitations and may be set to about 20 to 30 mm in consideration of ease of handling. 
         [0055]    The heater member  12  is preferably sheathed with an electrically-insulative sleeve. For instance, a sleeve made by knitting a heating wire, such as a nichrome wire, with a heat-resistant inorganic fiber, such as ceramic fiber, silica fiber, alumina fiber, and glass fiber, or an element formed by sheathing the heating wire with an electrically-insulative resin, is used as the heater member. It is particularly preferable that a sheath made from a sleeve which is woven from heat-resistant inorganic fiber has a two-ply structure. Even if the tape heater  10  is bent or twisted when a worker wraps the tape heater around a pipe, the potential risk of the heating wire projecting from a mesh of the sleeve is eliminated by doubly sheathing the heating wire with the sleeve, so that electrical insulation can be assured without fail. 
         [0056]    In the present invention, specific restrictions are not imposed on the layout of the heater member  12 , so long as both ends of the heater member  12  are connected to the lead wires  14 . However, from the viewpoint of operability and productivity, it is preferable that the two lead wires  14  is placed at one end of the tape heater  10 . For this reason, it is preferable that the heater member  12  is placed at the other end of the tape heater  10  in a folded manner, and that the entirety of the heater member is positioned in the shape of the letter “U”. In this case, an interval W 2  between portions of the heater member  12  is determined appropriately in accordance with the width W 1  of the fabric base  11 . In the case of the previously-described width W 1 , the interval W 2  may be set to 10 to 20 mm or thereabouts. A plurality of the heater member  12  may also be placed in the single tape heater  10 . 
         [0057]      FIG. 2A  is a cross-sectional view of the tape heater  10  taken along line B-B shown in  FIG. 1 , and only longitudinal ends of the tape heater are shown in an enlarged manner.  FIG. 2B  is a plan view of the tape healer when viewed in direction B in  FIG. 2A .  FIG. 2C  is a plan view of the tape heater when viewed in direction C in  FIG. 2A . As shown in  FIGS. 2A and 2B , in the tape heater  10 , an end  10   a  in a U-shaped portion  12   a  of the heater member  12  is folded along its brim, and a thus-folded portion  11   d  is stitched (L 2 ), thereby preventing exposure of the heater member  12  from an extremity of the tape heater. According to the necessity, a heat-resistant tape may be wrapped around the entirety of the folded portion  11   d.    
         [0058]    As shown in  FIGS. 2A and 2C , the other end  10   b  of the tape heater  10  is provided with a crimp portion  15  to which the heater member  12  and the lead wires  14  are to be connected. In the crimp portion  15 , each of ends  12   b  of the heater member  12  are exposed to the outside by penetrating through the first fabric base part  11   a  and connected to crimp terminals  16 , respectively. The lead wires  14  are connected to the ends through the crimp terminals  16 . An area where there is a connection to the crimp terminals  16  is protected by being covered with a heat-shrinkable tube  17 ; for instance, a silicon vanish glass tube, or the like. 
         [0059]    Moreover, the fabric base  11  is folded to a predetermined length so as to internally wrap the crimp portion  15 . A folded portion  11   e  is stitched (L 3 ), and an most extremity  11   f  of the folded portion  11   e  is folded to the inside and stitched (L 4 ). The crimp portion  15  is thus protected reliably. Moreover, the lead wires  14  are drawn to the outside from both sides of the folded portion  11   b . However, the lead wires are fixed by yarn (thread)  18  in such a way that force does not travel to the crimp terminals  16  when tensile force acts on the lead wires  14 . According to the necessity, the entirety of the folded portion  11   e  may also be wrapped with a heat-resistant tape. 
         [0060]    In order to manufacture the tape heater  10 , a conventional knitting or weaving machine can be used. For instance, an apparatus  30  schematically shown in  FIG. 3  is preferably used. The illustrated apparatus  30  has an first weaving machine  33   a  that weaves the first fabric base part  11   a  by supplying threads  13  from warp supply units  31   a  and a weft supply unit  32   a ; and a second weaving machine  33   b  that weaves the second fabric base part  11   b  by supplying the threads  13  from warp supply units  31   b  and a weft supply unit  32   b  (a step of forming fabric bases). A heater member supply unit  34  that supplies the heater member  12  is positioned downstream between the weaving machines  33   a  and  33   b , and U-shaped portions  12   a  of the heater members  12  are oriented toward a weaving direction F (from the left side toward the right side in the drawing). Further, a sewing machine  35 , that sews up the first and second fabric base parts  11   a  and  11   b  in die longitudinal direction thereof (a step of joining the fabric bases) while the heater member  12  is sandwiched between the first and second fabric bases  11   a  and  11   b , is positioned downstream of the heater member supply unit  34  (a step of disposing a heater member). In the present invention, the step of forming fabric bases, the step of disposing the heater member, and the step of joining the fabric bases may also be continuously performed. 
         [0061]    In the apparatus  30 , the heater member  12  is supplied from the heater member supply unit  34  to a position between the first fabric base part  11   a  formed by the first weaving machine  33   a  and the second fabric base part  11   b  formed by the second weaving machine  33   b . The sewing machine  35  sews up the first and second fabric base parts  11   a  and  11   b  while the heater member  12  is sandwiched between the first and second fabric base parts  11   a  and  11   b . Accordingly, the first and second fabric base parts  11   a  and  11   b  are continually woven, and the heater member  12  is intermittently supplied. Thereby, there is produced a long tape heater precursor  10 A having the heater members  12  sandwiched at predetermined intervals between the first and second fabric base parts  11   a  and  11   b , such as that shown in  FIG. 4 . 
         [0062]    The tape heater precursor  10 A is cut along an intermediate point K between one heater member  12  and another heater member  12 . The thus-separated respective precursors are subjected to edge processing shown in  FIG. 2 , whereby the tape heaters  10 , such as those shown in  FIG. 1 , are produced. 
       Second Embodiment 
       [0063]    In the first embodiment, the fabric base  11  is formed from two of the first and second fabric base parts  11   a  and  11   b . As shown in  FIG. 5  (a cross section corresponding to  FIG. 1B ), there is provided a tape heater  10 B in which the heater member  12  is sandwiched between the first and second fabric base parts  11   a  and  11   b  formed by folding back a single double-width fabric base  11 B. In the tape heater  10 B, a necessity for sewing up folded portions is obviated. 
         [0064]    In order to manufacture the tape heater  10 B, a conventional knitting or weaving machine can be used. For instance, an apparatus  30 B schematically shown in  FIG. 6  is preferably used. As illustrated, the apparatus  30 B has a weaving machine  33  that weaves a single double-width fabric base  11 B by supplying the threads  13  from the warp supply units  31  and the weft supply unit  32  (a step of forming a single fabric base). The heater member supply unit  34  that supplies the heater member  12  to an area corresponding to one-half the width of the fabric base  11 B (an area which is to become the second fabric base part  11   b  later) is positioned downstream of the weaving machine  33 . A fabric base folding machine  36  that folds the fabric base  11 B, to thus form the first and second fabric base parts  11   a  and  11   b , and that interposes the heater member  12  between the first and second fabric base parts  11   a  and  11   b  is positioned downstream of the heater member supply unit  34  (a step of folding a fabric base such that the heater member  12  is wrapped in). Further, the sewing machine  35  that sews up the thus-folded fabric base parts  11   a  and  11   b  in the longitudinal direction (a step of joining the fabric bases) is provided downstream the fabric base folding machine  36 . In the present invention, the step of forming a single fabric base, the step of folding the fabric base so as to internally wrap the heater member  12 , and the step of joining the fabric base may also be continuously performed. 
         [0065]    Even in the present embodiment, a long tape heater precursor  10 A, such as that shown in  FIG. 4 , is obtained. The thus-obtained tape precursor is cut, and the thus-separated sub-divisions are subjected to edge processing shown in  FIG. 2 , whereby the tape heaters  10 B can be continually manufactured. 
       Third Embodiment 
       [0066]    As shown in  FIG. 7  (a cross section corresponding to  FIG. 1B ), there is provided a tape heater  10 C having the heater member  12  sandwiched by a tubular-knitted or tubular-woven fabric base  11 C. In the tape heater  10 C, a necessity for sewing up both ends of the fabric base  11 C is obviated. 
         [0067]    In order to manufacture the tape heater  10 C, a conventional knitting or weaving machine can be used. For instance, an apparatus  30 C schematically shown in  FIG. 8  is preferably used. As illustrated, the apparatus  30 C has a tubular weaving machine  37  that weaves a tubular fabric base  11 C by supplying the threads  13  from the warp supply units  31  and the weft supply unit  32  (a step of forming a tubular fabric base). The tubular weaving machine  37  is supplied with the heater member  12  from the heater member supply unit  34 , and the heater member  12  is disposed inside of the woven tubular fabric base  11 C (a step of disposing a heater member inside of a tubular fabric base). The sewing machine  35  that flattens the tubular fabric base  11 C, to thus form the first and second fabric base parts  11   a  and  11   b , and that sews up the fabric base parts  11   a  and  11   b  in the longitudinal direction while the heater member  12  is sandwiched between the first and second fabric base parts  11   a  and  11   b  (a step of sewing up mutually-opposing faces of a tubular fabric base) is positioned downstream of the tubular weaving machine  37 . In the present invention, the step of forming a tubular fabric base, the step of disposing the heater member inside of the tubular fabric base, and the step of joining mutually-opposing faces of the tubular fabric base may also be continuously performed. 
         [0068]    Even in the present embodiment, the long tape heater precursor  10 A, such as that shown in  FIG. 4 , is obtained. The thus-obtained heater precursor is cut, and the thus-cut sub-divisions are subjected to edge processing shown in  FIG. 2 , whereby the tape heaters  10 C can be continually manufactured. 
       Fourth Embodiment 
       [0069]    As shown in  FIG. 9  (a cross section corresponding to  FIG. 1B ), a tape heater  10 D having the heater member  12  disposed in a flexible fabric base  11 D formed by weaving a heat-resistant thread is provided. In the tape heater  10 D, a necessity for sewing up both ends of the fabric base  11 D and the heater member  12  (see; for instance, L 1  in  FIG. 1 ) is obviated. In order to manufacture the rape heater  10 D, a conventional weaving machine can be used, and tee essential requirement is to include a step of forming a flexible fabric base while knitting heat-resistant threads and while internally wrapping the heater member  12 . 
       Fifth Embodiment 
       [0070]    In the tape heater  10 D of the fourth embodiment, the fabric base  11 D is woven so as to have a triple width, and the heater member  12  is disposed in a center fabric base  11 Da among trisected fabric bases. Both fabric bases  11 Db and  11 Dc on both sides of the center fabric base  11 Da are folded so as to contact the both surfaces of the center fabric base  11 Da, to thus form a three-layer structure. The thus-folded fabric base is sewed up over its entire thickness (L 5 ), whereby a tape heater  10 E can also be produced. 
         [0071]    In the respective embodiments, there can also be produced a long tape heater precursor  10 A′ in which two heater members  12 A and  12 B are disposed in parallel over the entire length of the fabric base  11 , as shown in  FIG. 11  (in correspondence with  FIG. 4 ). The tape heater precursor  10 A′ is cut into a required length (a cut location L). In each of separated pieces ( 10 ′,  10 ′), heater members  12 A and  12 B are pulled from one end of the fabric base  11  and connected together. Subsequently, the thus-connected heater members are housed in the fabric base  11 , and an end  11 A is sealed as shown in  FIG. 2B . Further, a lead wire is connected to the other end of the fabric base  11  as shown in  FIG. 2C , to thus produce a tape heater. By means of a long tape heater precursor  10 A′, the length of the tape heater can be freely designed, and further enhancement of production efficiency and an additional reduction in production cost can be attained. 
         [0072]    The invention was detailed with reference specified embodiments. However, it is obvious to a person skilled in the art that the invention may be variously modified and corrected without deviating from the spirit of the invention. 
         [0073]    This application is based on Japanese Patent Application No. 2008-090706 flied on Mar. 31, 2008 and an entirety thereof is incorporated herein by reference. 
         [0074]    Furthermore, all references cited here are incorporated by reference.