JP4596882B2 - heater - Google Patents

Description

  The present invention relates to a heater that prevents disconnection of a heating element made of a carbon fiber body.

  As a heater used for a heating device or the like, a heater using a heating element made of a carbon fiber body has been proposed (see, for example, Patent Document 1).

  As shown in FIG. 9, this type of heater (1) has a non-oxidizing atmosphere heating element storage space (2a) inside and an envelope (2b) having an airtight seal part (2b) at the end. ), A heating element (3) made of a carbon fiber body and housed in the heating element housing space (2a), and one end of the heating element (2b) passes through the hermetic seal part (2b) and the outside of the envelope (2). And a power feeding member (4) having the other end connected to the outer surface of the end of the heat generating element (3).

  The power supply member (4) has one end embedded in the hermetic seal (2b) and the other end connected to the outer surface of the end of the heating element (3), and one end of the envelope (2 ), And the other end is embedded in the hermetic seal portion (2b), and the inner lead rod (5) and the outer lead rod (6 And a metal foil (7) for connecting to the other.

The connection portion (5a) with the heating element (3) in the internal lead bar (5) is formed by spirally winding so that the inner diameter thereof is substantially uniform over the whole, and this connection portion (5a The inner lead rod (5) and the heating element (3) are connected to each other by inserting the end of the heating element (3) into the upper part.
JP 2001-6850

When the conventional heater (1) is connected to a power source (not shown) and energized, the current (i ₀ ^' ) from the power source is heated from the internal lead bar (5) constituting the power feeding member (4). And the inner part of the heating element (3) sandwiched between the internal lead bars (5) generates heat.

Here, paying attention to the connecting portion between the heating element (3) and the power feeding member (4), as shown in FIG. 10, the heating element is formed at the tip portion (5a1) of the connecting portion (5a) of the internal lead bar (5). Current (i ₁ ^′ ) flows intensively toward (3), but only a very small amount of current (i _n ^′ ) flows in the base side portion (the end side of the heating element (3)) (5a2). This is because when the current flows from the tip part (5a1) of the connection part (5a), the distance passing through the heating element (3) is shorter than the current flowing from the base part (5a2) of the connection part (5a). This is because the internal resistance is small.

  When current flows intensively from the tip (5a1) of the connection part (5a) toward the heating element (3), in the vicinity of the contact part between the tip (5a1) of the connection part (5a) and the heating element (3) A high temperature so-called heat spot (HS) is generated. And this heat spot (HS) part gradually evaporates in a non-oxidizing atmosphere to form a cavity, eventually leading to disconnection of the heating element (3), shortening the life of the heating element (3) There was a problem.

  SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a heater that prevents the heating element from being damaged by the occurrence of a heat spot and has a long heating element lifetime.

The heater according to claim 1 includes: an envelope (12) having a heating element storage space (12c) in a non-oxidizing atmosphere inside and an airtight seal portion (12b) at an end; and a carbon fiber body. A heating element (14) housed in the heating element housing space (12c) and one end projecting out of the envelope (12) through the hermetic seal part (12b) and the other end In the heater (10) having a power supply member (16) connected at a predetermined length to the outer surface of the end of the heat generating element (14), a connection portion of the power supply member (16) with the heat generating element (14) (18a) is composed of a spirally wound wire rod whose inner diameter is reduced toward the end of the heating element , and the connecting portion (14a) of the heating element (14) with the power supply member (16) The density is gradually increased as it goes toward the end of the heating element ”.

  In the present invention, since the density in the connection portion (14a) of the heating element (14) to the power feeding member (16) is configured to gradually increase toward the end of the heating element, the connection portion (14a) As the density increases, the internal resistance at the end of the heating element gradually decreases, and current easily flows. As a result, the amount of inflow of current from the power supply member (16) to the heating element (14) becomes uniform to some extent throughout the connection portion (14a), and the concentrated inflow of current as described above is eliminated, and the heat spot (HS) Generation is prevented.

The invention described in claim 2 is another embodiment of the connecting portion (18a ') of the power supply member (16) to the heating element (14), and "the heating element storage space (12c in the non-oxidizing atmosphere inside" ). ), An envelope (12) having an airtight seal portion (12b) at the end, a heating element (14) made of a carbon fiber body and housed in the heating element housing space (12c), The feeding member (16) whose end is projected outside the envelope (12) through the hermetic seal (12b) and whose other end is connected to the outer surface of the end of the heating element (14) with a predetermined length. ), The connecting portion (18a ′) of the power supply member (16) with the heating element (14) is a cylindrical member whose diameter decreases toward the end of the heating element. The density of the connecting portion (14a) between the heating element (14) and the power supply member (16) is gradually increased toward the end of the heating element. '' is there .

According to a third aspect of the present invention, in the second embodiment of the present invention, “ an envelope having a heating element storage space (12c) in a non-oxidizing atmosphere inside and an airtight seal portion (12b) at an end portion”. (12), a heating element (14) made of a carbon fiber body and housed in the heating element housing space (12c), and one end of the envelope (12) through the hermetic seal part (12b). Heat generation in the power supply member (34) in the heater (10), which is projected to the outside and the other end is connected to the outer surface of the end of the heat generator (14) with a predetermined length The connecting portion (34a) with the body (14) is constituted by a wire wound in a spiral shape so that the inner diameter thereof is substantially uniform over the whole, or a cylindrical member whose inner diameter is substantially uniform over the whole. By inserting the heating element (14), whose diameter is gradually increased as the outer diameter of the connection part (34a) with the power supply member (34) goes toward the end of the heating element, into the wire or cylindrical member Or, by inserting the rod-shaped heating element (14) into the wire or cylindrical member and then inserting the wedge-shaped compression member (36) into the heating element (14) with the small diameter portion first, the heating element The density of the connection portion (14a) with the power supply member (34) of (14) is configured to gradually increase toward the end of the heating element ”.

According to the first to third aspects of the invention, since the electrical resistance in the connection portion of the heating element with the power supply member is substantially uniform over the entire portion, current flows to the entire connection portion to some extent. Generation of heat spots is suppressed, and as a result, disconnection of the heating element can be prevented.

  Hereinafter, the present invention will be described in detail according to illustrated embodiments.

  As shown in FIG. 1, the heater (10) to which the present invention is applied is generally constituted by an envelope (12), a heating element (14), and a power feeding member (16).

  The envelope (12) has a cylindrical envelope body (12a) made of quartz glass or the like. At both ends of the envelope (12), an airtight seal portion (12b) is formed by a shrinkage method or a pinching method, etc., whereby a sealed heating element storage space ( 12c) is formed. The heating element storage space (12c) is filled with an inert gas such as nitrogen gas or argon gas in order to obtain a non-oxidizing atmosphere, and the heating element (14) is stored (of course, heat generation). A non-oxidizing atmosphere may be obtained by evacuating the body storage space (12c)).

  The heating element (14) is a rod-shaped member made of a carbon fiber body, and an inner lead rod (18) described later is connected to the outer surface of the end portion in a predetermined length in the axial direction thereof.

  Here, the fibrous body constituting the heating element (14) is a fiber assembly material such as a nonwoven fabric, a mat-like material, or a woven fabric mainly composed of carbon fibers, and is cut into a rod shape to form the heating element (14 ) Will be obtained.

  The type of carbon fiber constituting the carbon fiber body is not particularly limited. For example, natural fiber carbon fiber (natural fiber such as cotton is used as a raw material), polyacrylic carbon fiber, and cellulose type. Examples thereof include carbon fibers, phenol-based carbon fibers, furan-based carbon fibers, pitch-based carbon fibers (such as anisotropic pitch or isotropic pitch), and polyvinyl alcohol-based carbon fibers. It is also possible to use glassy carbon fibers (polycarbodiimide-based carbon fibers, etc.), graphitic carbon, amorphous carbon, carbon having these intermediate crystal structures, activated carbon fibers, etc. It is also possible to use it.

  The fiber diameter of the carbon fiber is not particularly limited, but is preferably about 5 to 20 μm, more preferably about 7 to 15 μm from the viewpoint of effectively exhibiting the heat generation function.

Further, the density of the carbon fiber body (that is, the density of the heating element (14)) is not particularly limited, but from the viewpoint of obtaining an excellent heat generation capacity, it is about 1.5 g / cm ³ or less. It is preferable that it is 0.01 to 0.6 g / cm ³ .

  The heating element (14) can be compressed by applying pressure from the outside, and the volume density increases as the compressibility increases, and the internal resistance decreases accordingly.

  The power supply member (16) includes an internal lead bar (18), an external lead bar (20), and a metal foil (22) made of a metal such as molybdenum.

  The internal lead rod (18) is a thin wire made of a metal such as molybdenum, for example, and one end is embedded in the hermetic seal portion (12b) of the envelope (12) and the other end Is connected to the outer surface of the end of the heating element (14) with a predetermined length.

The connecting portion (18a) of the internal lead bar (18) with the heating element (14) is spirally wound, and its inner diameter is on the side where the heating element (14) is inserted as shown in FIG. Set the inner diameter (r ₁ ) of the end to be approximately equal to the outer diameter (x) of the heating element (14) and the inner diameter (r ₂ ) on the opposite side to be smaller than the outer diameter (x) of the heating element (14) (In other words, the connecting portion (18a) is formed so that the inner diameter decreases toward the base of the internal lead rod (18)).

  The external lead rod (20) is a thin wire made of a metal such as molybdenum, for example, and has one end projecting outside the envelope (12) and the other end of the envelope (12). It is embedded in the hermetic seal (12b).

  The internal lead rod (18) and the external lead rod (20) are electrically connected via the metal foil (22) embedded in the hermetic seal portion (12b) of the envelope (12). .

In order to form the heater (10), first, as shown in FIG. 2 (a), the tip of the heating element (14) is attached to the connection portion (18a) wound in a spiral shape of the internal lead rod (18). insert. Here, the inner diameter of the connecting portion (18a) is set so that the side on which the heating element (14) is inserted has a large diameter and the opposite side has a small diameter, so the heating element (14) is connected to the connecting portion (18a). As it is pushed in, the tip of the heating element (14) is pushed by the connecting portion (18a) and gradually compressed. Then, when the tip of the heating element (14) is protruded from the small-diameter end of the connection portion (18a), the protrusion swells so that the outer diameter is the inner diameter (r ₂ of the small-diameter end of the connection portion (18a). (This bulge functions as a retaining element for the heating element (14)), and the connection between the internal lead rod (18) and the heating element (14) is completed (see FIG. 2 (b)). . Of course, the method of connecting the internal lead rod (18) and the heating element (14) is not limited to the above-described method, for example, taping the end of the heating element (14) to reduce the diameter, After this is inserted into the connecting portion (18a), the taping may be released.

  In addition, the density in the connection part (14a) with the internal lead rod (18) of the heating element (14) is gradually increased toward the end of the heating element (and this is the case in the connection part (14a)). It means that the internal resistance becomes smaller toward the end of the heating element, and current flows easily.)

  When the connection between the internal lead bar (18) and the heating element (14) is completed, these integrals are placed inside the envelope body (12a), and the external lead bar (20) and the metal foil (22) are mounted. It arrange | positions in the predetermined position of the edge part of an envelope main body (12a), and seals the both ends of an envelope main body (12a) by the well-known contraction method or pinching method etc. as mentioned above.

  By sealing the end of the envelope body (12a), a heating element storage space (12c) is formed inside, but at this time, the heating element storage space (12c) is formed by a well-known method. The atmosphere inside) is a non-oxidizing atmosphere, and the heater (10) is completed.

When the heater (10) is used, the protruding end (external lead bar (20)) of the power supply member (16) is connected to a power source (not shown). When the power supply switch is turned on, the current (i ₀ ) from the power supply is supplied to the heating element (14) through the power supply member (16), and the heating element (14) sandwiched between the power supply member (16) is supplied. The inner part generates heat.

Here, paying attention to the connection portion between the heating element (14) and the power supply member (16) (see FIG. 3), as described above, the connection portion (14a) of the heating element (14) to the power supply member (16). As the density at the end of the heating element gradually increases toward the end of the heating element and current flows easily, the heating element (14) is formed between the tip end part (18a1) and the base part (18a2) of the connection part (18a). The currents (i ₁ ) to (i _n ) flowing inward become uniform to some extent. In other words, as in the past, the concentrated flow of current to the specific part of the heating element (14) (near the contact part with the tip (18a1) of the connection part (18a)) is eliminated, and the generation of heat spots (HS) is suppressed. Thus, disconnection of the heating element (14) can be prevented.

  In the above-described embodiment, the connecting portion (18a) is formed by spirally winding the tip of the internal lead rod (18). However, as shown in FIGS. The connecting portion (18a ′) may be configured by connecting (or integrally forming) a cylindrical member made of metal such as molybdenum to the tip of (18) by means such as welding.

Here, the inner diameter (r ₁ ) of the end portion on the side where the heating element (14) is inserted is substantially equal to the outer diameter (x) of the heating element (14), and the inner diameter of the connecting portion (18a ′) The inner diameter (r ₂ ) of the end is set to be smaller than the outer diameter (x) of the heating element (14).

And also in this modification, there can exist the same effect as the above-mentioned Example. That is, the density in the connection portion (14a) of the heating element (14) gradually increases as it goes toward the end of the heating element, and the base end portion (18a2 ') from the distal end portion (18a1') of the connection portion (18a '). Since the currents (i ₁ ) to (i _n ) flowing into the heating element (14) become uniform to some extent during the period, the generation of heat spots (HS) is suppressed, and as a result, the heating element (14) is prevented from being disconnected. can do.

  Next, the heater (30) of the second embodiment shown in FIG. 6 will be described. In the following, differences from the above-described embodiment will be described, and the above description is used for the same portions.

  The heater (30) includes an envelope (32), a heating element (14), a power supply member (34), and a compression member (36).

  The envelope (32) has the same configuration as that of the above-described embodiment except that the material is formed of hard glass, and has a cylindrical envelope body (32a) at both ends thereof. An airtight seal portion (32b) is formed, and a heating element storage space (32c) is formed inside the envelope body (32a).

The power supply member (34) is a single thin member made of a metal such as molybdenum, and the connection portion (34a) of the power supply member (34) with the heating element (14) is spirally wound. The inner diameter (r ₃ ) is slightly smaller than the outer diameter (x) of the heating element (14) and is formed to be substantially equal over the whole (see FIG. 7).

  Unlike the previous embodiment, the power supply member (34) of the present embodiment does not employ a molybdenum metal foil for the following reason. That is, since the thermal expansion coefficient of hard glass, which is the material of the envelope (32), and molybdenum, which is the material of the power supply member (34), are approximately equal, power is supplied to the envelope (32) by thermal expansion during energization. This is because there is no gap at the boundary with the member (34), and it is not necessary to employ a metal foil for preventing the gap.

  Of course, in the present embodiment, the envelope (32) can be formed of quartz, and in this case, it is necessary to employ a metal foil as the power feeding member (34) as in the first embodiment. Also, the hard glass envelope (32) of this embodiment can be applied to the heater (10) of the first embodiment. In this case, as described above, as the power supply member (16), Since the inner and outer lead rods (18) and (20) can be formed of a single rod without using molybdenum metal foil, the configuration of the power feeding member can be simplified.

The compression member (36) is a substantially wedge-shaped member, and the material is not particularly limited as long as it has electrical conductivity and heat resistance. However, the heat dissipation capability, thermal conductivity, or electrical conductivity are not limited. In consideration of the properties and the like, it is preferable to use the same material (carbon fiber body) as the heating element (14). The shape of the compression member (36) has a predetermined length, and the outer diameter (m ₁ ) at one end in the axial direction is larger than the outer diameter (m ₂ ) at the opposite end. The size, the inclination angle, and the like may be appropriately set in consideration of the compression rate of the connection portion (14a) of the heating element (14).

  In order to form the heater (30), first, as shown in FIG. 7 (a), the end of the heating element (14) (more specifically, the connection part (14a) to the power supply member (34)) A notch is provided in the axial direction, and the compression member (36) is inserted here (of course, after connecting the connecting portion (34a) of the power supply member (34) and the heating element (14), the compression member ( 36) may be inserted.). At this time, since the compression member (36) is inserted into the cut portion of the heating element (14) with the small diameter portion first, the outer diameter of the connection portion (14a) of the heating element to the power supply member (16) The diameter gradually increases toward the end of the heating element.

Next, the connecting portion (34a) of the power supply member (34) wound in a spiral shape and the heating element (14) are connected.In the present embodiment, both members (14) ( 34) is connected. That is, the end of the heating element (14) is inserted into a cylindrical member (not shown) whose inner diameter can be adjusted (here, the compression member (36) is inserted along the axial direction as described above). Is inserted to close the cylindrical member. When the outer diameter of the cylindrical member becomes smaller than the inner diameter (r ₃ ) of the connecting portion (34a), the cylindrical member is inserted into the connecting portion (34a) (at this time, the heating element in the cylindrical member) The tip of (14) is arranged so as to protrude from the end of the connecting portion (34a) opposite to the side where the heating element (14) is inserted), and then the heating element (14) is connected Only the tubular member is extracted so as to remain in the portion (34a). Then, the heating element (14) and the compression member (36) swell and press the connection portion (34a) from the inside, thereby completing the connection between the heating element (14) and the power feeding member (34). (See FIG. 7 (b)).

Here, the outer diameter of the protruding portion of the heating element (14) is larger than the inner diameter (r ₃ ) of the connection part (34a) due to the expansion of the heating element (14) and the compression member (36). The bulging portion functions as a retaining member for the heating element (14).

  Note that the density of the connection portion (14a) of the heating element (14) to the power feeding member (34) gradually increases toward the end of the heating element, as in the above-described embodiment.

  Then, an integrated body of the heating element (14) and the power supply member (34) is disposed at a predetermined position of the envelope body (32a), and the end of the envelope body (32a) is sealed to form a heater ( 30) is completed, but since this is the same as the above embodiment, the description thereof is omitted.

When the heater (30) is used, the protruding end of the power feeding member (34) is connected to a power source (not shown) and the power source switch is turned on, as in the previous embodiment. Then, the current (i ₀ ) from the power source is supplied to the heating element (14) through the power feeding member (34), and the inner part of the heating element (14) sandwiched between the power feeding members (34) generates heat.

Also in this embodiment, the same effects as those of the above-described embodiment can be obtained. That is, since the internal resistance of the connection portion (14a) of the heating element (14) gradually decreases toward the end of the heating element, and the current easily flows, the connection portion (34a) of the feeding member (34) The currents (i ₁ ) to (i _n ) flowing from the front end portion (34a1) to the base side portion (34a2) toward the heating element (14) become uniform to some extent. Therefore, the concentrated flow of current to the specific part of the heating element (14) as in the prior art is eliminated, the generation of heat spots (HS) is suppressed, and disconnection of the heating element (14) can be prevented.

  In the present embodiment, the connection portion (34a) is configured by spirally winding the tip of the power supply member (34). For example, a cylindrical member made of a metal such as molybdenum (the inner diameter thereof is The outer diameter (x) of the heating element (14) is slightly smaller than the outer diameter (x) and is substantially equal throughout.) By connecting the tip of the power supply member (34) by means such as welding. You may comprise a part (illustration omitted).

  Further, the diameter of the connecting portion (14a) of the heating element (14) is not limited to the above-described method, for example, the connecting portion (14a) of the heating element (14) is the end of the heating element. The heating element (14) itself may be formed so as to increase in diameter as it goes toward.

  Furthermore, the compression member (36) used in this embodiment can be applied to the heater (10) of the first embodiment. In this case, heat is generated due to the presence of the compression member (36). Since the compressibility of the connection portion (14a) of the body (14) is further increased, the internal resistance of the end portion on the heating element side of the connection portion (14a) is further reduced. Therefore, the generation of the heat spot (HS) in the vicinity of the tip portion (18a1) in the connecting portion (18a) of the internal lead rod (18) is more effectively suppressed, and the breakage of the heating element (14) is more effectively prevented. Can be prevented.

Sectional view of the heater according to the present invention The figure which shows the method of connecting a heating element and an electric supply member (internal lead bar) Sectional drawing which shows the connection state of a heating element and electric power feeding member (internal lead bar) The figure which shows the method of connecting the modification and heating element of the connection part of an electric power feeding member (internal lead bar) Sectional drawing which shows the connection state of the modification of the connection part of an electric power feeding member (internal lead bar), and a heat generating body Sectional drawing of the heater of the other Example concerning this invention 6 is a diagram showing a method of connecting the heating element and the power supply member in the embodiment. 6 is a cross-sectional view showing a connection state between the heating element and the power supply member in the embodiment Sectional view showing a conventional heater The figure which shows the connection state of the heat generating body and internal lead bar in the conventional heater

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 30 Heater 12, 32 Envelope 14 Heating element 14a Connection part 16, 34 Power supply member 18a, 34a Connection part 36 Compression member

Claims (3)

An envelope having a heating element housing space in a non-oxidizing atmosphere inside and having an airtight seal at an end, a heating element made of a carbon fiber body and housed in the heating element housing space, and one end In the heater constituted by a power feeding member that is protruded to the outside of the envelope through the hermetic seal portion and the other end is connected to the outer surface of the end of the heating element at a predetermined length,
The connecting portion of the power supply member with the heating element is formed of a spirally wound wire whose inner diameter decreases toward the end of the heating element, and the connection portion of the heating element with the power supply member A heater is characterized in that the density in is gradually increased toward the end of the heating element. An envelope having a heating element housing space in a non-oxidizing atmosphere inside and having an airtight seal at an end, a heating element made of a carbon fiber body and housed in the heating element housing space, and one end In the heater constituted by a power feeding member that is protruded to the outside of the envelope through the hermetic seal portion and the other end is connected to the outer surface of the end of the heating element at a predetermined length,
The connection portion of the power supply member with the heating element is formed by a cylindrical member whose inner diameter decreases toward the end of the heating element, and the density of the connection portion of the heating element with the power supply member is the heating element. A heater characterized by being configured to gradually increase toward the end. An envelope having a heating element housing space in a non-oxidizing atmosphere inside and having an airtight seal at an end, a heating element made of a carbon fiber body and housed in the heating element housing space, and one end In the heater constituted by a power feeding member that is protruded to the outside of the envelope through the hermetic seal portion and the other end is connected to the outer surface of the end of the heating element at a predetermined length,
The connecting portion of the power supply member with the heating element is configured by a wire wound in a spiral shape so that the inner diameter thereof is substantially uniform over the entire surface, or a cylindrical member having an inner diameter substantially uniform throughout the entire surface. And
By inserting into the wire or tubular member a heating element that gradually increases in diameter as the outer diameter of the connecting portion with the power supply member goes toward the end of the heating element, or by attaching a rod-like heating element to the wire or cylinder By inserting the wedge-shaped compression member into the heating element after inserting the wedge-shaped compression member into the heating element,
A heater configured such that a density of a connection portion between the heating element and the power supply member gradually increases toward an end of the heating element.

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