JP3085536U - Circular heating elements and heaters - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a molybdenum foil inside a welded portion, a circular heating element and a heating device which are less likely to oxidize a molybdenum electric wire and which can be easily manufactured at a low cost. Aim. This invention inserts a metal filament wound in a coil shape into a glass tube bent in a substantially circumferential shape, and sandwiches both ends of the glass tube with edges of the metal filament. A circular heating element formed by fusing in a closed state, wherein the glass heating element is a circular heating element in which a portion adjacent to a fusion portion at both ends of the glass tube is linearly formed, Each end of the metal filament adjacent to each fused portion of the tube is formed in a straight line of 15 mm or more.

Description

[Detailed description of the invention]

[0001]

[Technical field to which the invention belongs]

 The present invention relates to, for example, a circular heating element used for a heating device such as a stove and a heating device using the circular heating element.

[0002]

[Prior art]

 Conventionally, as one of the heating appliances, a highly directional stove having a parabolic-shaped substantially circular radiating plate has been known. In such a stove, a circular heating element is arranged in order to increase the convergence rate of heat rays by a parabolic radiation plate.

FIG. 5 shows a conventional circular heating element. A circular heating element 51 is in a state where a coil-shaped metal filament 53 is inserted into a substantially circumferential glass tube 52. At the same time, both ends of the glass tube 52 are fused and argon gas is sealed inside the glass tube 52.

[0004] Further, at the fused portions at both ends of the glass tube 52, both ends of the metal filament 53 are connected to an external cord via a molybdenum foil in order to improve the sealing state of the glass tube. Connected to molybdenum wires.

[0005]

[Problems to be solved by the invention]

 However, when forming the glass tube 52, the conventional circular heating element 51 needs to bend outwardly at the right and left edges with a small radius of curvature, so that it takes time and effort to manufacture, and the yield is poor. It cannot be manufactured at low cost.

In the conventional circular heating element 51, the diameter of the metal filament 53 must be equal to or larger than a predetermined size for the purpose of preventing disconnection due to heat generation. Since the flexibility is low, the straight portions at both ends of the metal filament 53 cannot be elongated so as to straddle the front and rear portions of the bent portion of the glass tube 52.

Therefore, the heat of the coiled portion of the metal filament 53 is easily transmitted to the fused portions at both ends of the glass tube 52, and the heat of about 350 ° C. or more causes the molybdenum foil or the molybdenum foil inside the fused portion to be transferred. There is also a problem that the connected molybdenum electric wires are oxidized and the electric circuit is cut off.

An object of the present invention is to solve the above-mentioned problems of the conventional circular heating element, to manufacture it inexpensively and easily, and to oxidize the molybdenum foil and the molybdenum wire inside the fused portion. It is a provision of a circular heating element and a heating device that are unlikely to occur.

[0009]

[Means for Solving the Problems]

 This invention is based on the condition that a metal filament wound in a coil shape is inserted into a glass tube bent substantially circumferentially, and both ends of the glass tube are sandwiched by edges of the metal filament. A circular heating element formed by fusing at a position adjacent to the fused portion at both ends of the glass tube.

As an embodiment, both end edges of the metal filament adjacent to each fused portion of the glass tube can be formed in a straight line of 15 mm or more.

[0011] Further, a straight portion may be continuously provided at both ends of the circular central portion to form a horseshoe shape.

The glass tube may be formed of a quartz glass tube, and the metal filament may be formed of a tungsten filament.

[0013] Furthermore, a heating device can be formed by installing and forming the circular heating element at the center of a parabolic reflector.

In the circular heating element according to the present invention, if the length of the linear portions at both ends of the metal filament is 15 mm or more, the heat of the coil-shaped portion of the metal filament is less likely to be transmitted to the fused portion of the glass tube, This is preferable because the temperature of the fusion-bonded portion does not easily rise. Further, as a circular heating element for a stove having a parabolic-shaped substantially circular radiation plate, it is necessary that the glass tube has a diameter of about 80 to 120 mm. If the length of the linear portion at both ends of the metal filament is longer than 30 mm, the heat generation characteristics are reduced.

[0015]

[Embodiment of the invention]

 Hereinafter, an embodiment of a circular heating element according to the present invention will be described in detail with reference to the drawings. FIG. 1 shows a circular heating element (halogen heater) according to the present invention. The circular heating element 1 includes a quartz glass tube 2, a tungsten filament 3 as a metal filament, cords 7 and 7, and an insulator 9. , 9 and the like. The quartz glass tube 2 is formed by bending a quartz glass tube having a diameter of about 8.0 mm into a horseshoe shape with both ends closed. Linear portions 2b, 2b are continuously provided at both ends of a circular (about 2/3 of the circumference) central portion 2a, and both ends are adjacent to each other. Into the quartz glass tube 2, a tungsten filament 3 having a diameter of 0.5 mm is inserted.

The tungsten filament 3 has a central portion formed in a coil shape, and linear portions 3b, 3b of about 20 mm are continuously provided at both ends of the coiled portion 3a. Note that the coil-shaped portion 3a is formed by repeatedly bending a linear tungsten filament in the same direction at the same interval and then twisting, and the linear portion from the bending point to the bending point has a predetermined angle of phase. It is staggered and continuous.

FIG. 2 shows the linear portions 2b, 2b of the quartz glass tube 2 (showing a state in which the insulator 9 is removed), and FIG. 3 is a line AA in FIG. The cross section is shown. The linear portions 3b, 3b of the tungsten filament 3 are connected (welded) to substantially rectangular molybdenum foils 5, 5 each having a thickness of about 6 μm, and the respective molybdenum foils 5, 5 are connected to each other. At the rear ends, wires 6 and 6 made of molybdenum having a diameter of about 0.8 mm are connected (welded).

Further, the outer edges of the molybdenum wires 6, 6 are connected to the cords 7, 7 via cylindrical fittings 10, 10, respectively. Then, each edge of the quartz glass tube 2 is heated into a flat plate having a thickness of about 2 mm so as to sandwich the linear portion 3b of the tungsten filament 3, the molybdenum foil 5, and the tip of the molybdenum wire 6. It is fused and a fused portion 8 is formed (see FIG. 3). Then, the inside of the quartz glass tube 2 thus sealed is filled with an argon gas containing a gaseous halogen.

Further, at both ends of the quartz glass tube 2, cylindrical insulators 9, 9 each having a bifurcated tip are inserted with a cord therein, and the quartz glass tube is inserted between the bifurcated tip portions. 2 is grounded with the fused portion 8 of the edge 2 inserted. The insulators 9, 9 cover the connection between the molybdenum wire and the cords 7, 7.

The circular heating element 1 configured as described above is used by being arranged at the center of a parabolic reflector of a stove (far-infrared stove) 11 as shown in FIG. Then, when a voltage is applied to both ends of the cords 7, 7, the tungsten filament 3 generates heat and efficiently transfers the heat to the outside.

As described above, in the circular heating element 1, portions adjacent to the fusion parts 8, 8 at both ends of the quartz glass tube 2 are formed in a straight line (that is, the quartz glass tube 2 has a tip end). Since it has a closed horseshoe shape, it is not necessary to bend the quartz glass tube 2 with a small radius of curvature at the time of manufacture, so that manufacture is easy, and it is possible to manufacture with good yield and at low cost.

The circular heating element 1 has a tungsten filament 3 adjacent to each of the fused portions 8, 8 of the quartz glass tube 2. Since the heat of the coil-shaped portion 3a of the filament 3 is hardly transmitted to both ends of the tungsten filament 3, the oxidation of the molybdenum foils 5, 5 and the molybdenum wires 6, 6 inside the fusion parts 8, 8 due to the heat is prevented. It is unlikely to occur, and it is unlikely that the molybdenum foils 5, 5 and the wires 6, 6 made of molybdenum will be broken due to oxidation.

Note that the configuration of the circular heating element of the present invention is not limited to the above-described embodiments, and the configuration of the shape and structure of the quartz glass tube, the metal filament, and the like is not limited. It can be changed as needed without departing from the spirit of the invention.

For example, the metal filament is not limited to a tungsten filament, but can be changed to a filament made of another metal or the like. In addition, the shape of the coil-shaped portion of the metal filament is not limited to a shape twisted at a predetermined angle after continuous bending in the same interval and in the same direction, but can be changed to a simple spiral shape. .

When the shape of the coil is twisted at a predetermined angle after continuous bending in the same interval and in the same direction as in the above embodiment, a portion similar to a quartz glass tube is formed. Since it is reduced, there is an advantage that the quartz glass tube is hardly damaged.

Further, the metal interposed in the fused portion is not limited to molybdenum, and it is also possible to use a foil made of another metal. Further, the glass tube is not limited to the one made of quartz, but may be another kind of glass tube or one made of quartz filled with another substance.

When a glass tube made of quartz is used as in the above embodiment, there is an advantage that the glass tube is hardly damaged by heat.

Further, the molybdenum foil or the molybdenum electric wire may include a metal other than molybdenum, or may be changed to a foil or an electric wire made of another metal. In addition, the stove where the circular heating element is installed is not limited to the far infrared stove as in the above embodiment.

[0029]

[Effect of the invention]

 The circular heating element of the present invention is easy to manufacture because the portion adjacent to the fused portion at both ends of the glass tube is formed in a straight line, so that the glass tube does not need to be greatly bent at the time of manufacture. Yes, it can be manufactured with good yield and at low cost.

Further, in the circular heating element of the present invention, since both end edges of the metal filament adjacent to each fused portion of the glass tube are each formed in a straight line of 15 mm or more, the coiled portion of the metal filament is formed. Since the heat is not easily transmitted to both ends of the metal filament, oxidation of the molybdenum foil and the molybdenum electric wire inside the fused portion by the heat does not easily occur, and a situation in which the molybdenum foil and the molybdenum electric wire are broken due to oxidation is less likely to occur.

According to the heating device of the present invention, it is possible to obtain a heating device having the above-described characteristics of the circular heating element.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a circular heating element.

FIG. 2 is an explanatory view showing a linear portion of a quartz glass tube.

FIG. 3 is an explanatory diagram showing a cross section taken along line AA in FIG. 2;

FIG. 4 is an explanatory view showing a stove provided with a circular heating element.

FIG. 5 is an explanatory view showing a conventional circular heating element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Circular heating element 2 ... Quartz glass tube 2a ... Center part 2b ... Linear part 3 ... Tungsten filament 3a ... Coil part 3b ... Linear part 4 ... Cord 5 ... Molybdenum foil 6 ... Molybdenum wire 7 ... Cord 8 ... Fused part 9 ... Insulator 10 ... Cylindrical fitting 51 ... Circular heating element 52 ... Quartz glass tube 53 ... Metal filament

Claims (5)

[Utility model registration claims] 1. A glass tube bent substantially in a circular shape,
A circular heating element formed by inserting a metal filament wound in a coil shape and fusing both ends of the glass tube with the edges of the metal filament sandwiched therebetween, wherein the two ends of the glass tube are fused. A circular heating element in which a portion adjacent to the fused portion is formed linearly. 2. A circular heating element according to claim 1, wherein both end edges of the metal filament adjacent to each fused portion of the glass tube are formed in a straight line of 15 mm or more. 3. The circular heating element according to claim 1, wherein a linear portion is connected to both ends of the circular central portion to form a horseshoe shape. 4. A circular heating element according to claim 1, wherein said glass tube is formed of a quartz glass tube, and said metal filament is formed of a tungsten filament. 5. A parabolic reflector in the center of the reflector.
A heating appliance formed by installing the circular heating element according to 2, 3, or 4.