JPH0321034Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a so-called indirect heating device that indirectly heats an object to be heated using a heating element such as an electric heater.

In heating means using electric heaters etc.
Depending on whether the heat transfer between the heating element and the object to be heated is generally direct or indirect, it can be broadly classified into so-called direct heating and indirect heating. The latter type of indirect heating is used when the object to be heated needs to be heated to a certain degree uniformly over its entire surface. It has been thought that it is better not to have any intervention. This is because if there are any inclusions between them, in addition to heat transfer phenomena such as radiation and convection in the air, heat is unevenly transferred through the inclusions, which tends to cause temperature unevenness. It is based on an old idea.

However, even if we say that nothing exists, there is still space in between, and since air exists,
In reality, extremely complex heat transfer takes place through convection. In addition, since air has poor thermal conductivity, the response of the heated object to temperature changes of the heating element is extremely poor, and a large amount of heat escapes to the outside.
Heat loss is also large.

In particular, the above-mentioned problems have a serious effect when controlling the temperature of an object to be heated. In other words, the temperature of the heated object is generally controlled by changing the amount of heat generated by the heating element, such as by switching between heating and non-heating. Temperature unevenness occurs in the air layer surrounding the object, which causes more complex convection, which tends to promote uneven heating. In addition, due to the uneven temperature of the heated object and poor response, accurate control cannot be achieved even if the temperature of the heated object is measured and the amount of heat generated by the heating element is changed while feeding back the results. The temperature of the heated object is difficult to stabilize.

This invention was made to solve the above-mentioned problems with indirect heating means, and the object to be heated 1 is placed in a cylindrical heat-insulating case 3 whose wall is made of a heat insulating material. , A heating element 2 is placed on the inner periphery of the heat insulation case 1 so as to surround the object to be heated 1, and an intermediate member formed by interlacing thin wires with high thermal conductivity is tightly packed inside the heat insulation case 3. The present invention provides an indirect heating device characterized by uniform filling.

Hereinafter, the configuration of this invention will be explained in detail based on an illustrated embodiment.

The illustrated embodiment is a case where an object to be heated 1 is indirectly heated by a heating element 2 consisting of an electric heater. In such a case, the object to be heated 1 is usually surrounded by a heat insulating case 3, and the heating element 2 is housed inside the heat insulating case 3 to heat the object to be heated. The heat retaining case 3 has a highly heat insulating structure in which, for example, a heat insulating material 6 is filled between an inner case 4 and an outer case 5.

In this invention, in the above case, an intermediate member 7 formed by intertwining fine wires with high thermal conductivity, such as metal wires, is interposed between the object to be heated 1 and the heating element 2.
It is preferable that this intermediate member 7 uniformly fills the entire space existing between the heated body 1 and the heating element 2. Therefore, in the illustrated embodiment, the intermediate member 7 is placed inside the heat insulating case 3. It is evenly filled throughout.

The intermediate member 7 can be made of thin metal fibers woven regularly like a mesh, or made of countless fibers simply intertwined at random, but in either case, all It is desirable to have a uniform structure in the direction as well. These metal fibers have a certain degree of flexibility and are easily deformed, so even if the inside of the heat insulating case 3 or the heated object 1 has a somewhat complicated shape, it is possible to make them adhere evenly to every corner. I can do it.

The intermediate member 7 filled in the heat insulation case 3 is
Air is held in countless narrow spaces formed between lines that are intertwined with each other, trapping it so that it cannot move freely.
Even if the heating element 2 is heated, no convection occurs (microscopically, convection occurs only in the very narrow space mentioned above).And most of the heat generated by the heating element 2 is transferred to the intermediate member 7. Since the intermediate member 7 is made of intertwined thin wires with high thermal conductivity, such as metal wires, the heat is transmitted to the heated object 1 quickly and uniformly.

From the above points, according to this invention, the uneven heating of the heated object 1 mainly caused by air convection is eliminated, and the heat generated by the heating element 2 is
Since the heat is transmitted quickly through the intermediate member 7, the responsiveness of the heated object 1 to the temperature change of the heating element 2 is improved. Therefore, the temperature of the object to be heated 7 can be easily controlled, and the temperature can be controlled to an appropriate temperature at any time. At the same time, less heat escapes to the outside, and heat loss can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an embodiment of this invention, and FIG. 2 is a sectional view taken along the line A--A in FIG. 1... Heated object, 2... Heating element, 7... Intermediate member.

Claims (1)

[Claims for Utility Model Registration] 1. A heated object 1 is placed in a cylindrical heat-insulating case 3 whose wall is made of a heat insulating material, and the above-mentioned heat-insulating case 1 is placed so as to surround the heated object 1. An indirect heating device characterized in that a heating element 2 is disposed on the inner periphery of the heat insulating case 3, and an intermediate member formed by intertwining fine wires with high thermal conductivity is densely and uniformly filled in a heat insulating case 3. 2. The indirect heating device according to claim 1 of the utility model registration claim, in which the intermediate member is made of regularly woven metal fibers. 3. The indirect heating device according to claim 1 of the utility model registration claim, in which the intermediate member is made of randomly intertwined metal fibers.