JPS5854577A - Sheathed heater - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sheathed heater having Fi-controlled heat distribution characteristics.

For example, a sheathed heater having a sinusoidal heat distribution characteristic in the axial direction is used as a nuclear fuel simulating heating element.

Conventionally, this type of sheathed heater is known to have a moderate configuration in order to obtain predetermined heat distribution characteristics. For example, if the heating element is tubular or rod-shaped, and its wall thickness (cross-sectional area) is changed according to the heat distribution characteristics, then the pitch of the heating element is changed according to the heat distribution characteristics. There are the following types that form a spiral cutting groove.

However, the former is difficult to machine), and if the heating element undergoes buckling deformation due to expansion pressure and there is an expansion difference between the heating element and the outer tube, the two will come into contact and the heating element and outer tube will bend. , causing breakage. The latter is difficult to machine and requires high machining costs, and the pitch of the spiral cutting grooves is uneven, with some parts being dense and some parts being sparse, so the expansion of the heating element cannot be sufficiently absorbed. There is a drawback that there is no

The present invention has been made in view of the previous concerns, and it is possible to easily obtain a predetermined heat distribution characteristic, and is easy to manufacture.
Moreover, the present invention provides a sheathed heater that can prevent breakage accidents by alleviating expansion and deformation.

That is, the sheathed heater of the present invention includes a heating element formed of a strip material having different width dimensions in the longitudinal direction.

Embodiments of the present invention illustrated in the drawings will be described below.

FIG. 1 shows an embodiment of the sheathed heater of the present invention. In the figure, 1 is a heating element, 2 is an outer tube into which this heating element 1 is inserted, and 3 is a product inside this outer tube 1.

The heating element 1 is a coil having a heat distribution characteristic of a sine curve, and as shown in the developed view in FIG. It is made of wood shaped like a mancoil. As shown in FIG. 3, the width of the strip material 6 is made to vary along its longitudinal direction in accordance with the heat generation distribution characteristic of a sine curve. In other words, the width S1 of the strip material 6 is set to be the largest at both ends, and the smallest at the center, and the width decreases successively in the longitudinal direction from both ends to the center. It is formed like this. Note that the width dimension of the band material 6 is made different by continuously cutting both side portions along the longitudinal direction.

Incidentally, speaking about the dimensions of the strip material 6, the thickness Q, 4
wm, width at both ends 813.2m, width at the center S! 2,
It is 5M. When manufacturing the heating element 1,
Both sides of the strip material cut to a predetermined length are removed by electric discharge machining to form a strip material 6 having different width dimensions along the longitudinal direction.
Furthermore, the heating element 1 is manufactured by winding this strip material 6 in a mencoil shape with a constant winding diameter and a constant pitch.

Therefore, the coil-shaped heating element 1 has a width dimension that continuously decreases from both ends to the center due to the band material 6.

Therefore, in a sheathed heater equipped with such a heating element 1, when a constant current is conducted to the heating element 1 through the terminal 4.4, each part of the heating element 1 along the longitudinal direction changes its electrical resistance value. Heat is generated with a corresponding amount of heat, and as a whole, a heat generation distribution characteristic forming a sine curve as shown in FIG. 3 is obtained. Figure 1llE3 is a diagram showing the amount of heat generated at each part of the heating element 1 in the axial direction. That is, heating element 1
Both ends are formed by both ends of the strip material 6, and since the width dimension S1 is the largest, the electrical resistance value is the smallest,
Accordingly, the amount of heat generated is the smallest. The central part of the heating element 1 is formed at the central part of the strip material 6, and since its width dimension S is the smallest, the electric resistance value is the largest, and accordingly, the amount of heat generated is the largest. As the width of the band 6 gradually decreases from both ends of the heating element 10 to the center, the electrical resistance increases, and the amount of heat generated also increases accordingly. As the width of the heating element 10 changes in the axial direction, the electrical resistance value of each part also changes, and the amount of heat generated in each part of the heating element 1 changes continuously accordingly. . Therefore, the heating element 1 as a whole can form a heat generation distribution characteristic that is a sine curve that is large in the center and small in both ends.

A sheathed heater equipped with this heating element 1 can be used, for example, as a nuclear fuel simulating heating element that requires a sine curve heat generation distribution characteristic.

In addition, it is preferable that the width of the band material 6 forming the heating element 1 is continuously changed along the longitudinal direction in order to improve the accuracy of the sine curve of the heat generation distribution characteristic, but the width is not limited to this. Alternatively, the width of the strip 6 may be varied stepwise along the longitudinal direction by not cutting a straight line on one side, but cutting only the other side into a tube. You can also do it.

FIG. 4 is a developed view of a band material 6 showing another embodiment of the heating element 1. In this example, both ends 6* of the tri material 6
+6m and the central part 6b are made of different materials, and by setting the dimensions of each part to be different along the longitudinal direction of the material 6, the electrical resistance value of each part can be made different. The heat generation distribution IVI exhibits a sine curve as a heating element l.
It is assumed that the property is obtained. For example, both ends gm of the strip material 6
.

6a is formed from a nickel-chromium alloy, and the central portion 6b is formed from an iron-chromium-aluminum alloy. Then, this band material 6 is wound into a coil shape with a constant winding diameter and a constant pitch to form a heating element.

In addition, to improve the accuracy of the heat distribution characteristics of the heating element.
As an auxiliary measure, in addition to changing the material of each part of the band in the band as described in other embodiments, changing the thickness of the band or material may be combined. fever
Made of cloth, the body is easy to control the heat generation state.
In order to enable specific manufacturing, it is preferable that the windings, width, and width of the coil be constant. In addition, drawings 40 (-) are not limited to single-shaft type heaters.
It can also be applied to 2-shaft type, IJ type, etc.
As explained above, the sheathed heater of the present invention is constructed by making the width dimension of Figure 4 different along the longitudinal direction.

By changing the electrical resistance value in the longitudinal direction,
1.Since it is equipped with a formed heating element, the heating element can be placed anywhere.
It is possible to easily obtain constant heat distribution characteristics through terminals, and the heating element is easy to manufacture and the manufacturing cost is low.

Also, if the heating element is a coil forest with a certain number of pipes,
It is possible to release the expansion of one heating element when heat is generated, and it is possible to prevent damage to the heating element or outer tube due to buckling, and to prevent damage such as breakage of the connection part of the heating element. Furthermore, the accuracy of heat distribution can be improved by a simple means of varying the thickness of the heating element element or varying the thickness of each heating element element. Therefore, the sheathed heater C requires 9 heat distribution characteristics.
It is extremely excellent.

) Brief explanation [A diagram showing the heat distribution characteristics of the heating element of Toru = A developed diagram of the heating element in the first other embodiment...Heating element, 2...Outer tube, 3...Insulation Powder, 4...6...band material.

Applicant's agent Patent attorney Takehiko Suzue, Commissioner of the Patent Office
Kazuo Wakasugi 1. Indication of the case - MSCS-154226 No. 2, Name of the invention Sheathed Heater 3, Person making the amendment Relationship to the case Patent applicant (3L) 7) Tokyo Shiba YM Electric Co., Ltd. 4, Agent 5, Voluntary amendment 7, Contents of amendment (Figure 1 of the 11 drawings attached to the application is corrected as shown in the attached sheet.

Claims (1)

[Scope of Claims] 1. A sheathed heater characterized by comprising a heating element formed from a strip material whose width dimension varies in the longitudinal direction. 2. The sheathed heater according to claim 1, wherein the band material is formed in a coil shape.