JP2000200676A - Tubular wire heater and heating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tubular wire heater capable of surely and easily coating an optimum oxide film on the surface of a heating wire and supporting the heating wire, having a size not protruding outwardly from the outer diameter of an closure tube, with little dispersion of service life and miniaturizable, and to provide a heating device using the heater. SOLUTION: This tubular wire heater includes a heat resistance and electrically insulating closure tube, a heating wire 4 arranged in the closure tube and a conductive guide member 5 connected to the heating wire 4, fixed to the closure tube in a closed area 3 at the end of the closure tube and provided with a vent hole 6 for communicating the inside and outside of the closure tube. The heating device uses the heater.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tubular heating wire heater used for cooking, heating, drying, baking and the like, and a heating device provided with the tubular heating wire heater.

[0002]

2. Description of the Related Art A metal wire, such as a nichrome wire (nickel-chromium alloy) or a Kanthal wire (iron-chromium-aluminum alloy), which generates resistance heat, is wound into a coil to form a heating wire, and the heating wire has heat resistance. Tubular heating wire heaters, which are housed in an envelope made of ceramics such as quartz or alumina (aluminum oxide) or iron with an electrically insulating coating, have various structures due to their simple structure and low cost. Widely used in equipment and various fields.

[0003] In such a tubular heating wire heater, a dense metal oxide film is formed on the surface of the heating wire that generates resistance, thereby suppressing evaporation of the heating wire even at a high temperature to reduce thinning. It is known that, by setting the oxygen partial pressure atmosphere in equilibrium with the surface oxide film, even if the temperature is raised to about 600 to 1200 ° C., it can withstand a long service life. Since it is preferable that oxygen is always supplied to the inside of the surrounding tube, the tube-type heating wire heater 1 is provided with a vent hole at an end portion for communicating the inside and outside of the tube. For example, when quartz is used as the envelope 2, as shown in FIGS. 7A and 7B, the end of the envelope 2 is heated and pressed by a pair of dies such as pinchers to close the closed portion (sealed portion). A stop portion 3 is formed. The closing portion 3 is fixed by embedding and sealing a linear introduction portion 42 formed continuously to the end of the coil-shaped portion 41 of the heating wire 4 which generates heat, in softened quartz. The portion has a pair of ventilation holes 6 and 6 formed by weakening the pressure.
When the tube-type heating wire heater 1 is supplied with power through introduction portions 42, 42 (one of which is the same shape and not shown) provided at both ends, the wound coil-shaped portion 41 is provided.
Generates heat. At this time, the outside air flows through the inside of the surrounding tube 2 through the ventilation holes 6 and 6 at the ends, and an oxide film is formed on the surface of the heating wire 4, so that the life can be extended.

However, in the case where the closed portion (sealing portion) 3 is formed by pressing the end of the envelope 2 made of quartz having the above-described configuration, deviations in the diameter and thickness of the quartz tube and heating of the quartz tube can be prevented. The size of the ventilation holes 6 and 6 varies depending on conditions and the like, and the amount of oxygen taken into the outer tube 2 varies. For example, when the ventilation hole 6 is crushed and the ventilation amount is small, the surface of the heating wire 4 Is reduced and no oxide film is formed, and the heating wire in the high temperature state evaporates in a short period of time and becomes thinner. Was invited. When the ventilation hole 6 is large, the oxide film is preferably formed, but the support fixing strength of the linear introduction portion 42 having a smaller diameter than the surrounding tube 2 at the end of the heating wire 4 may be reduced.

When the end of the outer tube 2 is heated and pressed to form a closed portion (sealing portion) 3, the end of the electric insulating tube 2 becomes flat, and A wide portion protruding from the outer diameter is formed, which prevents the downsizing of the heating device when the tubular heating wire heater 1 is incorporated into the heating device, particularly when the heating device is provided with a base covering the closed portion 3 at the end. Was a factor.

Further, the heating wire 4 buried at the center of the end of the outer tube 2 moves when pressed by the pincher, causing a displacement, and a part of the heating wire 4 comes into contact with the inner surface of the outer tube 2. To lower the heat generation temperature in that part.
Devitrification and cracking sometimes occurred on the wall.

In view of the above, without forming an occluded portion by pressing the end portion, a plug-like body made of glass compound is packed at the end portion of an envelope made of quartz or ceramics to form an occluded portion. There is a hot wire heater. In this case, a linear end portion of the heating wire is buried in the center of the glass compound, and a ventilation hole communicating between the inside and outside of the tube is provided around the end.

However, in the case of the tubular heating wire heater having such a configuration, complicated work is required to fix the straight end of the small heating wire at the center of the glass compound. there were.

[0009]

That is, in a tubular heating wire heater in which the inside and outside of the surrounding tube are communicated with each other to form an oxide film on the surface of the heating wire to extend the service life, the inside of the surrounding tube is taken into consideration. There has been a demand for improvements in reducing the variation in the opening area of the pores and in the means for forming and supporting and introducing the heating wire.

Therefore, the present inventors have further studied various closed portions having a ventilation hole which supports and introduces the heating wire of the tubular heating wire heater and communicates the inside and outside of the envelope tube.

According to the present invention, it is possible to reliably and easily form an optimum oxide film on the heating wire surface and to support the heating wire, and to have a size not protruding outward from the outer diameter of the envelope. It is an object of the present invention to provide a tubular heating wire heater which can be downsized without variation in life and a heating device using the heater.

[0012]

According to a first aspect of the present invention, there is provided a tubular heating wire heater comprising: an outer tube having heat resistance and electrical insulation; a heating wire disposed in the outer tube; A conductive introduction member connected to a heat wire and fixed to the outer tube at a closed portion at an end of the outer tube and provided with a ventilation hole communicating between the inside and the outside of the outer tube; It is characterized by the following.

The introduction member for connecting and supporting the heating wire is formed in a cylindrical shape opened inside and outside the outer tube, and the inside of the tube is used as a ventilation hole to measure the flow of outside air into the outer tube, and an oxide film is formed on the surface of the heating wire. I made it possible. This tubular introduction member is provided at the closed portion at the end of the outer tube, but is less likely to be crushed at the time of closing. In a tubular heating wire heater of the same rating, a ventilation hole having the same opening diameter is obtained, and each of the heaters is provided with the same diameter. This has the effect of reducing the variation in the thickness of the oxide film formed on the heating wire surface of the heating wire heater.

The cross-sectional shape of the cylindrical introduction member is not limited, such as a cylindrical shape or a rectangular tube shape. Further, the material of the introduction member may be made of conductive ceramics in addition to conductive metal. Further, the present invention is not limited to the case where the ventilation holes are provided on both of the introduction members provided at both ends of the surrounding tube, and it is sufficient if at least one of the introduction members has the ventilation holes.
A tubular heating wire heater according to a second aspect of the present invention is characterized in that the outer tube is selected from ceramics, glass, and metal coated with insulation.

The material of the outer tube may be ceramics such as alumina (aluminum oxide) having heat-resistant electrical insulation, hard glass such as quartz, alumina silicate glass, or the inner surface of a metal tube made of iron or stainless steel. It can be applied even if it has a vitreous coating.

According to a third aspect of the present invention, the tubular heating wire heater is characterized in that the introduction member is fixed to a closed portion formed by contracting the end of the outer tube.

In the case where the outer tube is made of a glass tube made of quartz or the like, the glass tube is heated and melted toward the outer surface of the introducing member provided in the end to reduce the diameter, thereby welding the two. It is also possible to use a tube whose end is reduced in diameter at the time of molding the outer tube.

Further, the heater in which the stepped portion is formed by contracting the end of the outer tube can be easily assembled to the heating device by using the stepped portion.

[0019] A tubular heating wire heater according to a fourth aspect of the present invention is characterized in that the introduction member is fixed to a closed portion made of a heat-resistant plug-like member joined to the end of the outer tube. And

Since the closing portion is formed of a plug-like body and fixes the introducing member having a diameter larger than the diameter of the heating wire, the supporting and fixing can be strengthened and the center of the closing portion can be easily arranged. I can do it.

The tubular heating wire heater according to a fifth aspect of the present invention is characterized in that the closed portion at the end of the outer tube to which the introduction member is fixed does not protrude from the outer diameter of the outer tube. I do.

Since this tubular heating wire heater has no protruding portion outside the outer diameter of the surrounding tube, it can be reduced in size and can be easily attached to a heating device.

A tubular heating wire heater according to a sixth aspect of the present invention is characterized in that the heating wire is wound in a coil shape and its end is fitted and connected to the introduction member.

Both parts are connected by fitting means such that the coil portion of the heating wire is wound around the introduction member or fitted into the large diameter portion. Note that the connection between the two may be reinforced by welding or caulking.

As the material of the heating wire, nichrome (nickel-chromium alloy), kanthal (iron-chromium-aluminum alloy) or the like can be used, and the wire diameter may be selected variously according to the output.

A heating device according to a seventh aspect of the present invention includes the tubular heating wire heater according to any one of the first to sixth aspects, and a support member for supporting the tubular heating wire heater. It is characterized by having.

In the heating device, the tubular heating wire heater is supported by a supporting member which also serves as a power supply, and a reflector and a guard are combined as necessary, so that the heating device is used for cooking utensils such as ovens and heaters, stoves and kotatsu. It can be used as various heating devices such as for heating and for drying and baking in various other manufacturing industries.

[0028]

Embodiments of the present invention will be described below with reference to the drawings. The figure shows a tubular heating wire heater 1A, FIG. 1 is a partially cutaway front view, FIG. 2 (a) is a longitudinal sectional view in which an end which is a main part is enlarged, and FIG. 2 (b) is a figure (a). It is a cross-sectional view of the part cut | disconnected along arrow aa in ().

In the figure, reference numeral 2 denotes a heat-resistant and electrically insulating outer tube made of a straight tubular transparent or translucent quartz tube, 3 and 3 denote closed portions formed at both ends of the outer tube 2, and 4 denotes an outer tube. It has a coil-shaped portion 41 wound around a heating wire made of a nichrome (nickel-chromium alloy) wire disposed in the surrounding tube 2.

Reference numeral 5 denotes an introduction member, which is heated from the outside in the vicinity of the end of the outer tube 2 and reduced in diameter to be buried in the closed portions 3 and 3 formed in steps to support and fix. Have been. The introduction member 5 is made of a metal such as stainless steel (SUS) or nickel (Ni), which does not need airtightness but is easily welded and is formed of a conductive metal in a cylindrical shape. The cylindrical hollow portion forms a ventilation hole 6 communicating the inside and outside of the outer tube 2, and the end of the coil portion 41 of the heating wire 4 is provided at the end protruding into the outer tube 2. Are wound, and the two parts are firmly mechanically and electrically connected to each other by welding and swaging. The portion of the introduction member 5 extending outside the outer tube 2 serves as a terminal portion, and these constitute the tubular heating wire heater 1A.

When a power supply member (not shown) is connected to the introduction members 5 and 5 of the tubular heating wire heater 1A to energize,
The coil portion 41 of the heating wire 4 connected to the introduction members 5, 5 generates heat. At this time, outside air flows through the ventilation holes 6, 6 of the cylindrical introduction members 5, 5, and a dense oxide film is formed on the surface of the heating wire 4. The attached matter and dirt are burned to form an oxide film or evaporate and scatter.

Thereafter, the tubular heating wire heater 1A is repeatedly used by being energized.
As a result of the supply of outside air through the ventilation holes 6, 5, an oxide film is formed on the surface of the heating wire 4, so that thinning due to evaporation of the heating wire 4 can be prevented and the life of the heater 1 </ b> A can be extended.

The tubular heating wire heater 1A calculates the required air flow rate in the outer tube 2 and
Can be determined. When a plurality of tubular heating wire heaters 1A,... Having the same rating are used in parallel, the same conditions are applied by using the introducing member 5 having the same diameter of the ventilation hole 6. As a result, ventilation of each tube-shaped heating wire heater 1A,
Can improve the quality of the tubular heating wire heaters 1A,... With little variation in the life of the heating wires 4,.

Further, since the heating wire 4 is electrically connected to the heating wire 4 by using the cylindrical introduction member 5 having a larger diameter than the heating wire 5, no local stress is applied to the heating wire 4. Since it can be located at the center of the outer tube 2, the coil-shaped portion 41 having a high temperature is directly connected to the outer tube 2.
Can be prevented from coming into contact with the inner surface of the outer tube, and the damage due to the variation of the heat generation temperature distribution and the devitrification and cracks of the outer tube 2 can be reduced.

Further, the end of the outer tube 2 has a stepped shape formed by reducing the diameter so as to be welded to the introduction member 5 and does not protrude outward from the outer diameter of the outer tube 2. The shape heating wire heater 1A can be downsized, and this step can be used as a locking portion when it is attached to the heating device.

FIGS. 3 to 6 show a main part of another embodiment of the tubular heating wire heater according to the present invention.
The same parts as those in FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted.

FIG. 3 is a longitudinal sectional view of an end portion of the tubular heating wire heater 1B. In this heater 1B, the outside of the coil portion 41 of the heating wire 4 is fitted to one end of a cylindrical introduction member 5. A cap-shaped large-diameter portion 51 having an inner diameter to be provided is provided, and is the same as FIG. 2 except for a connection portion between the introduction member 5 and the heating wire 4. It may be reinforced by welding or caulking in addition to the joint.

FIG. 4 is a longitudinal sectional view of an end portion of a tubular heating wire heater 1C. This heater 1C has an outer tube 2 made of ceramics such as alumina (aluminum oxide) or quartz, here alumina. A plug-like body made of a heat-resistant glass compound to which a cylindrical introduction member 5 is fixed in the center is joined as a closing portion 7A near the end of the surrounding tube 2. Since the closing portion 7A is formed of a plug-like body and fixes the introduction member 5 having a diameter larger than the wire diameter of the heating wire 4, the supporting and fixing can be strengthened and the center of the closing portion 7A of the heating wire 4 can be secured. Can also be easily installed. The introduction member 5 and the heating wire 4
Are connected in the same configuration as shown in FIG.

The tubular heating wire heaters 1B and 1C shown in FIGS. 3 and 4 have the same functions and effects as those of the tubular heating wire heater 1B shown in FIGS.

FIG. 5 is a partial cross-sectional front view showing an essential part of an end portion of the tubular heating wire heater 1D, and FIG. 6A is a portion cut along the line bb in FIG. (B)
The figure is a side view of the heater 1D as viewed from the right in FIG.

In this tubular heating wire heater 1D, a cylindrical introduction member 5 is formed at the end of the envelope 2 made of ceramics or quartz, in this case, alumina, as shown in FIG. A plug made of a fixed heat-resistant ceramic is provided as the closing portion 7B.

The closed portion 7B has a large-diameter hole 71 in which the end of the outer tube 2 is accommodated in the center on one end surface side, a small-diameter hole 72 connected to the large-diameter hole 71, and a small-diameter hole. It has a cylindrical plug-like body formed with a medium-diameter hole 73 for accommodating the introduction member 5 which is connected to the hole 72 and opened at the center on the other end surface side.

The large diameter portion 52 is provided in the closed portion 7B.
A cylindrical introduction member 5 having an inside formed of a conductive material having a small-diameter portion 53 and having a ventilation hole 6 is accommodated therein. The introduction member 5 has projections 54, 54 formed by cutting an intermediate portion of the small diameter portion 53 at two locations in a direction substantially orthogonal to the member axis, and two projections 54, obliquely spaced apart from the projections 54, 54. Protrusions 55, 55 cut and raised at the place are provided. Also,
In the figure, reference numeral 56 denotes a connecting piece for connecting the large diameter portion 52 and the small diameter portion 53,
The large-diameter portion 52, the small-diameter portion 53, the protrusions 54, 55, and the connection piece 56 are made of a metal material having the same thickness and are integrally or integrally formed by press working or the like.

The coiled portion 41 of the heating wire 4 is wound around the outer periphery of the large diameter portion 52 of the introduction member 5, and the large diameter portion 52 and the heating wire 4 have resistance at several turns 57 at the end. They are electrically and mechanically connected by means such as welding or arc welding.

After the heating wire 4 is connected to the introduction member 5, the distal end side of the small diameter portion 53 penetrates into the large diameter hole 71, the small diameter hole 72, and the medium diameter hole 73 of the closing portion 7B. The projections 55, 55 skewed by this penetration are pressed and contracted to pass through the small-diameter hole 72, but pass through the medium-diameter hole 73.
At the same time, the projections 54 and 54 are locked by the small-diameter hole 72 forming wall on the large-diameter hole 71 side. That is, as a result of the projections 54, 54 and 55, 55 being locked on both sides of the small diameter hole 72 forming wall, the introduction member 5 is prevented from moving and fixed. At the same time when the introduction member 5 and the closing portion 7B are assembled, the surrounding tube 2 is also attached.

The tubular heating wire heater 1D is also similar to the heating wire heaters 1A to 1C described in the above embodiment.
The tubular heating wire heater 1D is used while being repeatedly energized, but outside air is supplied into the surrounding tube 2 through the ventilation holes 6, 6 of the introduction members 5, 5, so that the surface of the heating wire 4 An oxide film is formed, and thinning due to evaporation of the heating wire 4 can be prevented, and the life of the heater 1D can be extended. Further, the use of the closing portion 7B enables the heating wire 4 to be accurately and firmly held on the central axis of the outer tube 2.

The tubular heating wire heaters 1B to 1D shown in the embodiments of FIGS. 3 to 6 also have a plurality of tubular heating wire heaters having the same rating, and the introduction member 5 having the same diameter of the ventilation hole 6. Is used, it is possible to provide a tube-type heating wire heater having the same operational effects as those of the above-described embodiment and having improved quality with little variation in life.

Further, the tubular heating wire heaters 1A to 1D
Is supported by a support member that also serves as a power supply, and a reflector and a guard are combined as necessary, for cooking utensils such as ovens and heaters, for heating such as stoves and kotatsu, and for drying in various manufacturing industries. It can be used as various heating devices such as for firing.

These heating devices have the advantages that the heating wire heater has a long life, has little variation, and has no extra protrusion, so that it can be downsized.

[0050]

According to the first aspect of the invention, outside air is circulated through the ventilation hole of the cylindrical introduction member in the outer tube, and a dense oxide film is formed on the surface of the heating wire. In addition, it is possible to prevent thinning due to evaporation of the heating wire and to prolong the life of the tubular heating wire heater.

Moreover, in each tubular heating wire heater of the same rating, the closed portion is formed under the same condition using the introducing member having the same diameter of the ventilation hole. As a result of ventilation through the ventilation holes of the same diameter, there is little variation in the life of each piece.In addition, by using a large-diameter introduction member, the fixing strength of the introduction member in the closed portion, the accuracy of the arrangement position, and the heating wire It is possible to provide a tubular heating wire heater with improved quality such as increased connection strength.

According to the second aspect of the present invention, by using an envelope selected from ceramics, glass or metal having insulation coating having heat resistance and electrical insulation,
A tubular heating wire heater having the same effects as those described in the first aspect can be provided.

According to the third aspect of the present invention, since the stepped portion is formed in the closed portion formed by shrinking the end of the outer tube, the tubular heating wire heater is utilized by utilizing the stepped portion. There is an advantage that it can be easily assembled to the heating device.

According to the fourth aspect of the present invention, since the closing portion is formed of a plug-like body and fixes the introduction member having a diameter larger than the diameter of the heating wire, the supporting and fixing can be made firm and the closing can be performed. There is an advantage that it can be easily arranged at the center of the section.

According to the fifth aspect of the present invention, it is possible to provide a tube-type heating wire heater that can reduce the size of the surrounding tube and can easily perform the work of attaching the surrounding tube to the heating device.

According to the sixth aspect of the present invention, the connection between the heating wire and the introduction member can be made firm and easy.

According to the seventh aspect of the present invention, since the tubular heating wire heater having the effects described in the first to sixth aspects is provided, maintenance with a long service life and little variation in the service life can be performed. It is possible to provide a heating device which is easy and can be miniaturized and which can be applied to various uses.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view showing an embodiment of a tubular heating wire heater of the present invention.

2 is an enlarged view showing an end portion which is a main part in FIG. 1, wherein FIG. 2 (a) is a longitudinal sectional view, and FIG. 2 (b) is a view taken along the line aa in FIG. 1 (a).
It is a cross-sectional view of the part cut | disconnected along a line.

FIG. 3 is a longitudinal sectional view showing a main part of another embodiment of the tubular heating wire heater of the present invention.

FIG. 4 is a longitudinal sectional view showing a main part of another embodiment of the tubular heating wire heater of the present invention.

FIG. 5 is a longitudinal sectional view showing a main part of another embodiment of the tubular heating wire heater of the present invention.

6 is a transverse cross-sectional view of a portion cut along the line bb in FIG. 5, and FIG. 6B is a side view of the heater 1D in FIG. 5 viewed from the right.

7A and 7B show an end portion of a conventional tubular heating wire heater, wherein FIG. 7A is a longitudinal sectional view, and FIG. 7B is a side view of FIG.

[Explanation of symbols]

 1A to 1D: Tubular heating wire heater 2: Surrounding pipe 3, 7A, 7B: Closed portion 4: Heating wire 41: Coiled portion 5: Introducing member 6: Vent hole

Claims (7)

[Claims] 1. An outer tube having heat resistance and electrical insulation; a heating wire disposed in the outer tube; and an outer tube connected to the heating wire at a closed portion at an end of the outer tube. And a conductive introducing member provided with a ventilation hole communicating between the inside and outside of the outer tube. 2. The tubular heating wire heater according to claim 1, wherein the outer tube is selected from ceramics, glass, and metal coated with insulation. 3. The tubular heating wire heater according to claim 1, wherein the introduction member is fixed to a closed portion formed by contracting an end of the outer tube. 4. The tubular heating wire according to claim 1, wherein the introduction member is fixed to a closing portion made of a heat-resistant plug-like body joined to an end of the envelope tube. heater. 5. The tube according to claim 1, wherein the closed portion at the end of the outer tube to which the introduction member is fixed does not protrude from the outer diameter of the outer tube. Type heating wire heater. 6. The tubular heating wire heater according to claim 1, wherein the heating wire is wound in a coil shape and an end thereof is fitted and connected to the introduction member. . 7. A heating apparatus comprising: the tubular heating wire heater according to claim 1; and a support member for supporting the tubular heating wire heater.