TW202010885A - Carbon wire heater capable of suppressing current concentration of the carbon wire heating body - Google Patents

Abstract

The present invention relates to a carbon wire heater, which is characterized in including: a glass member; and a carbon wire heating body. The carbon wire heating body is housed inside the glass member and generates heat by a power supply. The carbon wire heating body is formed by integrating and knitting carbon single-fiber bundles into a plurality of carbon fiber bundles with a thread shape. The weight per unit length of the above carbon wire heating body is in the range of 1 g/m to 5.1 g/m. There is no carbon fiber bundle in the space formed by the knitted plurality of carbon fiber bundles knitted.

Description

Carbon wire heater

The present invention relates to a carbon wire heater in which a carbon wire heating body is housed in a glass member, and particularly to a carbon wire heater that suppresses current concentration in a carbon wire heating body.

Regarding the carbon wire heater, the applicant proposes the invention described in Patent Document 1. The carbon wire heater described in Patent Document 1 will be described with reference to FIGS. 6 to 9.

The heater shown in FIG. 6 includes a carbon wire heating element 12 and a long and small-diameter quartz glass tube 13 (referred to simply as a glass tube 13) that houses both ends of the carbon wire heating element 12 and is open. At both ends 13a and 13b of the glass tube 13, glass tubes 14a and 14b with larger diameters are stored, and the wired carbon material 20 is compressed and stored inside the glass tubes 14a and 14b with large diameters. In addition, the outer end portions of the both end portions 13a and 13b are sealed and sealed by sealed terminal portions 18a and 18b.

The sealed terminal portions 18 a and 18 b have cylindrical sealing members 15 a and 15 b containing quartz glass, and one end is fused to both end portions 13 a and 13 b of the glass tube 13. In the sealing members 15a and 15b, connecting wires 16a and 16b for supplying electric power to the carbon wire heating element 12 are arranged. On the outer peripheral surface of a part of the connecting wires 16a and 16b, a coefficient of thermal expansion is formed on the connecting wires 16a and 16b. The thermal expansion inclined portions 17a and 17b that change in the radial direction.

The sealing members 15a and 15b are cylindrically formed with small-diameter portions 15a1, 15b1, large-diameter portions 15a2, 15b2, and rising portions 15a3, 15b3 connecting the small-diameter portions 15a1, 15b1 and the large-diameter portions 15a2, 15b2. body. The inner peripheral surfaces of the small-diameter portions 15a1, 15b1 are fused with the outer peripheral surfaces of the thermal expansion inclined portions 17a, 17b, and the end surfaces of the large-diameter portions 15a2, 15b2 and the end surfaces 13a, 13b of the large-diameter glass tube 13 Fuse. Thereby, the inside of the glass tube 13 is sealed.

The connection wires 16a and 16b include Mo (molybdenum) or W (tungsten) rods. The front ends of the connecting wires 16a and 16b are sharply projected so that they can be easily connected to the wire carbon material 20 compressed and stored in the large-diameter glass tubes 14a and 14b.

In addition, as described above, the heat expansion inclined portions 17a, 17b are formed on the sealed terminal portions 18a, 18b, and the outer peripheral surfaces of the connecting wires 16a, 16b. The thermal expansion inclined portions 17a, 17b include tungsten glass layers 17a1, 17b1 formed on the outer peripheral surface of the connecting wires 16a, 16b, and the layer stacked thereon, for example, having a thermal expansion coefficient of 8×10 ^-7 /°C (0-300°C) The 96% silicate glass layer 17a2, 17b2. That is, the thermal expansion inclined portions 17a, 17b are formed so that the thermal expansion coefficients in the radial direction of the connecting wires 16a, 16b become smaller.

According to the heater having such a structure, the outer peripheral surfaces of the connecting wires 16a, 16b are provided with thermal expansion inclined portions 17a, 17b whose thermal expansion coefficient changes in the radial direction, and the connecting wires 16a, 16b are attached to the glass via the thermal expansion inclined portions 17a, 17b Since the members (small diameter portions 15a1, 15b1), deformation due to thermal expansion can be alleviated. Moreover, the mechanical strength against external force becomes stronger, and the operation is convenient.

In the heater shown in FIG. 6, the carbon wire heating element 12 housed in the glass tube 13 uses the following carbon wire, that is, from about 3000 to 3500 carbon fibers with a diameter of 2 to 15 μm, for example As shown in the side view of FIG. 7 (the glass tube is shown in cross-section), 8 bundles of fiber bundles 12a integrated with a single carbon fiber bundle with a diameter of 7 μm are knitted into a braided rope shape or a group braided shape with a diameter of about 2 mm. In the above case, the stitching span of the line is about 2 to 5 mm.

In addition, FIG. 8 is a side view schematically showing the inside of the fiber bundle 12a (only the outline is shown by chain lines to show the inside) incorporated as described above. As shown in the figure, a core 19 including 2 to 3 straight (straight) fiber bundles is arranged inside the plurality of bundled fiber bundles 12a. In this way, the strength is previously maintained by arranging the core 19 within the plurality of fiber bundles 12a incorporated therein. [Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2005-294007

[Problems to be solved by the invention]

However, as shown in the longitudinal cross-sectional view of FIG. 9, a plurality of fiber bundles 12a covering the periphery of the core wire 19 are incorporated, but the core wire 19 is not incorporated but is in a straight state. However, the length of the core wire 19 in a straight state is shorter than that of the braided wire (fiber bundle 12a), so the resistance value becomes lower, and the current tends to concentrate accordingly. Therefore, there is a problem that the temperature in the core wire 19 easily rises, and the temperature of the core wire 19 becomes higher than the temperature of the braided wire (fiber bundle 12a) when the current is applied.

Therefore, there is a problem that the carbon (C), which is the main component of the carbon wire, and the SiO evaporated from the silica glass tube react in the core wire 19 in comparison to the woven wire (fiber bundle 12a), resulting in breakage The line gradually progressed. [Number 1] SiO(s)＋C(s)→Si(s)＋CO(g)

The present invention has been completed to solve the above-mentioned technical problems, and its object is to provide a carbon wire heater that suppresses the generation of current concentration in a carbon wire heating element and seeks to extend the life of the carbon wire heating element. [Technical means to solve the problem]

The carbon wire heater of the present invention completed to achieve the above object is characterized by comprising: a glass member; and a carbon wire heating body which is housed inside the glass member and generates heat by power supply; and the above carbon wire heating system will be A plurality of carbon fiber bundles integrated with a single carbon fiber bundle are formed by weaving into a linear shape. The weight per unit length of the above carbon wire heating element is in the range of 1 g/m to 5.1 g/m, within the plurality of carbon fibers incorporated above There is no carbon fiber bundle in the space formed by the bundle. In addition, it is preferable that the carbon wire heating element is composed of 5 to 20 bundles of the carbon fiber bundles formed by collecting the carbon single fiber bundles having a diameter of 5 to 15 μm, and the whole is formed of 15,000 to 60,000 carbon single fibers.

In this way, according to the present invention, the carbon wire heating element housed in the glass member does not include a straight core wire as before, but is configured to incorporate a plurality of carbon fiber bundles. Thereby, there is no current concentration in the core wire with a low resistance value, so that the heating of the carbon wire heating body can be made uniform. As a result, the progress of the disconnection caused by the chemical reaction can be suppressed, and the life of the carbon wire heating element can be prolonged. In addition, the resistance value per unit length becomes higher compared to the case where the core wire is included, so when the same current value flows, the output can be improved compared to the case where the core wire is included. In addition, compared with the previous carbon wire heating element including the core wire, it can be manufactured inexpensively. [Effect of invention]

According to the present invention, it is possible to obtain a carbon wire heater that suppresses the generation of current concentration in a carbon wire heating element and seeks to extend the life of the carbon wire heating element.

Hereinafter, an embodiment of the carbon wire heater of the present invention will be described with reference to the drawings. FIG. 1 is a side view showing an embodiment of the carbon wire heater of the present invention (glass tubes are shown in cross section), which is a diagram showing the main part having the features of the carbon wire heater of the present invention. 2 is a longitudinal cross-sectional view of the carbon wire heater shown in FIG. 3 is a side view showing an enlarged view of a part of the surface of the carbon wire heating body contained in the glass tube.

In addition, the carbon wire heater shown in FIGS. 1 and 2 is similar to the previous heater shown in FIG. 6 to supply power to the carbon wire heating body accommodated in the glass tube and generate heat. 6 shows the same structure.

The carbon wire heater 1 shown in FIGS. 1 and 2 includes: a carbon wire heating element 2 that generates heat by power supply; and a glass tube 3 (glass member) that houses the carbon wire heating element 2 in the tube, Furthermore, it has sealed terminal portions (not shown) at both ends. The above-mentioned glass tube 3 is, for example, a quartz glass tube formed of quartz glass and transmitting light (radiant heat). The inner diameter is, for example, 2.6 mm, and the outer diameter is, for example, 5 mm.

The above-mentioned carbon wire heating element 2 is formed by weaving a plurality of carbon fiber bundles 2a composed of extremely fine carbon single fiber bundles into a braided rope shape or a braided shape as shown in FIG. 3(a) or FIG. 3(b) Compared with the conventional metal or SiC heating element, the linear shape has a smaller heat capacity and excellent temperature rise and fall characteristics, and is also excellent in high temperature durability in a non-oxidizing environment.

In addition, the carbon wire heating element 2 is produced by weaving a plurality of fine carbon single fiber fiber bundles (carbon fiber bundle 2a), so it is more flexible and conforms to shape deformation than a heating element containing pure carbon materials Excellent.

In the example shown in the present embodiment, one woven from eight carbon fiber bundles 2a is used. As shown in FIG. 2, the inside of the eight bundles of carbon fiber bundles 2a incorporated is a cavity, and does not contain a core wire of carbon wire (carbon fiber bundle) as in the previous structure. That is, the carbon fiber bundle 2a does not exist in the space formed by the plurality of knitted carbon fiber bundles 2a. In this way, there is no core wire, and there is no current concentration toward the core wire, so there is no local temperature rise of the core wire, and the life of the carbon wire heating element 2 can be prolonged. In addition, the resistance value per unit length becomes higher compared to the case where the core wire is included, so when the same current value flows, the output can be improved compared to the case where the core wire is included. In addition, it can be manufactured at a lower cost than the previous carbon wire heating element including the core wire.

Furthermore, the above-mentioned carbon wire heating element 2 will be described in more detail. As described above, for the carbon wire heating element 2, a plurality of bundles (eight bundles in this embodiment) of carbon fiber bundles 2a are knitted in a braided rope shape or a braided shape with a diameter of about 2 mm. The carbon fiber bundle 2a is preferably a collection of about 3000 carbon single fibers having a diameter of 5 μm to 15 μm, for example, a carbon single fiber bundle having a diameter of 7 μm.

In addition, as a whole of the carbon wire heating element 2, it is preferable that the carbon single fiber is about 15,000 to 60,000. For example, if one carbon fiber bundle 2a is formed by 3000 carbon single fibers, the carbon wire heating element 2 is preferably formed by incorporating 5 to 20 carbon fiber bundles 2a.

In the above case, the braided span of the wire is about 2 mm to 5 mm, and, as shown in FIGS. 3(a) and (b), the braided angle θ of the carbon fiber bundle 2a is set between 10° and 40° Specific angle. That is, when the weaving angle is as small as 10° (FIG. 3(a)), the length of the carbon fiber bundle 2a per unit length (1 m) becomes shorter, and the weight becomes about 1 g/1 m. If the knitting angle is less than 10°, the bendable shape cannot be maintained, which is not good.

On the other hand, when the knitting angle is as large as 40° (FIG. 3(b)), the length of the carbon fiber bundle 2a per unit length (1 m) becomes longer, and the weight becomes about 5.1 g/m. In this way, if the wedging angle is increased, for example, the amount of wire included per unit length increases, and the resistance value increases. As a result, the output can be increased from the previous structure. Furthermore, if the knitting angle is greater than 40°, the rigidity is improved but the flexibility is insufficient, and it is difficult to lead around, which is not good. As described above, in the carbon wire heater of the present invention, the weight per unit length of the carbon wire heating element is set in the range of 1 g/m to 5.1 g/m.

In the carbon wire heater 1 configured as above, when the carbon wire heating element 2 is energized to generate heat, radiant heat is radiated from the glass tube 3 along the shape of the carbon wire heating element 2 (linear in this embodiment).

In this manner, according to the embodiment of the carbon wire heater of the present invention, the carbon wire heating element 2 housed in the glass tube 3 is configured to incorporate a plurality of carbon fiber bundles 2a without including a straight core wire. As a result, the current concentration in the core wire with a lower resistance value can be suppressed, and the heating of the carbon wire heating element 2 can be made uniform. As a result, the progress of the disconnection caused by the chemical reaction can be suppressed, and the life of the carbon wire heating element 2 can be extended. Also, the resistance value per unit length becomes higher compared to the case where the core wire is included, so that when the same current value flows, the output can be improved compared to the case where the core wire is included. In addition, compared with the previous carbon wire heating element including the core wire, it can be manufactured inexpensively.

In addition, in the above embodiment, the number of carbon fiber bundles 2a constituting the carbon wire heating element 2 has been described as eight, but the number of fiber bundles 2a incorporated is not limited. In the above-described embodiment, the carbon wire heating element 2 (and the glass tube accommodating the same) has been described as being linear, but it is not limited to this, and may be rectangular or curved. [Example]

Next, the carbon wire heater of the present invention will be further described based on the embodiments. <Experiment 1> In Experiment 1, the carbon wire heater shown in the above embodiment was used to verify whether the output relative to the supplied electric power was higher than before. (Example 1) In Example 1, a carbon wire heating element (a total of 30,000 carbon single fibers) with a diameter of about 2 mm formed by weaving 3,000 carbon fiber bundles with a diameter of 7 μm into 10 carbon fiber bundles was formed. The programming angle is set to 30°.

(Comparative example 1) As the carbon wire heater of the previous structure, a core wire containing two bundles of straight carbon fiber bundles in the carbon wire heating element was used as Comparative Example 1. The carbon fiber bundle of each core wire is formed of 3000 carbon single fibers. The braided wires arranged around the two bundles of core wires used the same conditions as in Example 1. That is, a carbon fiber bundle integrated with 3000 carbon single fiber bundles with a diameter of 7 μm is used to form 10 bundles. The knitting angle was set to 30°, and the diameter of the carbon wire heating element was set to about 2 mm in the same manner as in Example 1.

In this experiment, for the carbon wire heaters of Example 1 and Comparative Example 1, the supply current was increased stepwise from 0 A to 25 A, and the heater output (W) at this time was measured. As a result of this experiment, the relationship between the supply current value (A) of Example 1 and Comparative Example 1 and the heater output (W) is shown in the graph of FIG. 4. In the graph of FIG. 4, the vertical axis is the heater output (W), and the horizontal axis is the supply current (A). As shown in the graph, according to the carbon wire heater of the present invention (Example 1), the output is increased by about 35% compared to the carbon wire heater (Comparative Example 1) previously constructed. It is considered that the reason is that the structure of Example 1 has a higher resistance value per unit length than the structure including the core wire as in Comparative Example 1, so that when the same current value flows, the output is more improved.

<Experiment 2> In Experiment 2, the carbon wire heater shown in the above embodiment was used to verify whether the life was improved compared to the previous one. (Example 2) In Example 2, a carbon wire heating element (a total of 30,000 carbon single fibers) with a diameter of about 2 mm and a heating portion length of 200 mm formed by weaving 3000 carbon fiber bundles with a diameter of 7 μm into 10 carbon fiber bundles was integrated into 10 bundles. . The programming angle is set to 30°.

(Comparative example 2) As the carbon wire heater of the previous structure, a case where two core wires including a straight carbon fiber bundle are contained in the carbon wire heating element is used as Comparative Example 2. The carbon fiber bundle of each core wire is formed by 3000 carbon single fibers.

In the same manner as in Example 2, the braided wire arranged around the two bundles of core wires used a bundle of 3000 carbon fiber bundles with a diameter of 7 μm integrated into 10 bundles of about 2 mm in diameter. The programming angle is set to 30°. As in Example 2, the diameter of the carbon wire heating element was set to about 2 mm, and the length of the heating section was set to 200 mm.

In this experiment, the carbon wire heaters of Example 2 and Comparative Example 2 were measured when the output of each heater (500 W, 580 W, 680 W, 750 W, 780 W) was continuously energized. Time of disconnection. The results of this experiment are shown in the graph of FIG. 5. In the graph of FIG. 5, the vertical axis is the disconnection time (h), and the horizontal axis is the heater output (W). As shown in the graph, according to the carbon wire heater of the present invention (Example 2), it was confirmed that the time before disconnection was longer than that of the previously constructed carbon wire heater (Comparative Example 2).

The results of the above embodiments confirm that according to the carbon wire heater of the present invention, the heater output can be increased compared with the previous one, and the life of the carbon wire heating element can be extended.

This application is based on the Japanese patent application 2018-120817 filed on June 26, 2018, the contents of which are incorporated herein by reference.

1: Carbon wire heater 2: Carbon wire heating element 2a: carbon fiber bundle 3: glass tube 12: Carbon wire heating element 12a: fiber bundle 13: Glass tube 13a: end 13b: end 14a: glass tube 14b: glass tube 15a: Sealing member 15b: Sealing member 15a1: Small diameter part 15b1: Small diameter part 15a2: Large diameter section 15b2: Large diameter section 15a3: Rise 15b3: Rise 16a: connecting cable 16b: cable 17a: Thermal expansion slope 17b: Thermal expansion slope 17a1: Tungsten glass layer 17b1: Tungsten glass layer 17a2: Silicate glass layer 17b2: Silicate glass layer 18a: Sealed terminal 18b: Sealed terminal 19: core wire θ: programming angle

Fig. 1 is a side view showing an embodiment of a carbon wire heater of the present invention (glass tubes are shown in a cross-sectional view), which is a view showing a main part of the carbon wire heater. Fig. 2 is a longitudinal sectional view of the carbon wire heater of Fig. 1. 3(a) and 3(b) are enlarged side views showing a part of the surface of the carbon wire heating body contained in the glass tube. 4 is a graph showing the results of Example 1 and Comparative Example 1 of the present invention. 5 is a graph showing the results of Example 2 and Comparative Example 2 of the present invention. Fig. 6 is a cross-sectional view of a previous heater in which a carbon wire heating body is enclosed in a glass tube. 7 is a side view showing the configuration of the carbon wire heating element included in the previous heater of FIG. 6. Fig. 8 is a side view showing the core wire of the carbon wire heating element of Fig. 7. 9 is a longitudinal cross-sectional view of the carbon wire heating element shown in FIGS. 7 and 8.

1: Carbon wire heater

2: Carbon wire heating element

2a: carbon fiber bundle

3: glass tube

Claims (2)

A carbon wire heater characterized by comprising: Glass components; and A carbon wire heating element, which is housed inside the above-mentioned glass member, generates heat by power supply; and The above carbon wire heating system is formed by knitting a plurality of carbon fiber bundles integrated into a single carbon fiber bundle into a linear shape, The weight per unit length of the above carbon wire heating element is in the range of 1 g/m to 5.1 g/m, There is no carbon fiber bundle in the space formed by the plurality of carbon fiber bundles incorporated above. The carbon wire heater as in claim 1, wherein the above carbon wire heating system The carbon fiber bundles formed by collecting the carbon single fiber bundles having a diameter of 5 to 15 μm are woven into 5 to 20 bundles, and the whole is formed of 15,000 to 60,000 carbon single fibers.

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