JPS6311755B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in heat-generating molded bodies made of inorganic fibers for electric furnaces, which are applied to the walls of electric furnaces.

Recently, instead of bricks, fiber molded bodies made of heat-resistant inorganic fibers with a small amount of binder added to them and shaped into blocks have been used for the walls of electric furnaces.
Furthermore, a heat-generating molded body has been provided in which a heating wire is embedded in one side of the molded body.

As mentioned above, molded bodies made of heat-resistant inorganic fibers are lightweight and have excellent heat insulation properties, and in the case of heat-generating molded bodies with heating wires embedded in one side, special supports are used to support the heating wires. It has the advantage of not requiring heating wires, and is characterized by high safety because the heating wires are not exposed.However, on the other hand, the good insulation properties of inorganic fibers are a problem, and it is often buried. There is a drawback that the heat conduction effect that is dissipated from the heating wire to the inside of the furnace through the fiber layer portion is suppressed.
In addition, the temperature around the heating wire becomes significantly higher than the temperature inside the furnace, which causes the fibers in that area to deteriorate quickly.Furthermore, because the strength of the fiber molded product is low, the expansion and contraction of the heating wire causes the molded product to become unstable. parts may fall off.

This invention was made in order to solve the various problems mentioned above, and in a heat-generating molded body in which a heating wire is embedded in an inorganic fiber molded body, the heat of the heating wire is effectively applied to the outside of the molded body. To provide a heating molded body made of inorganic fiber for an electric furnace, which can be safely used for a long period of time by stably holding a heating wire without fear of the molded body part falling off due to the expansion and contraction of the heating wire as it is drawn out. The main purpose is to

In order to achieve the above object, the present invention provides a heating wire embedded in one side of a fiber molded layer formed by molding inorganic fibers to a required thickness, in which the heating wire is made of ceramic fiber having heat resistance and heat conductivity. short fibers and a fire-resistant inorganic binder mixed with water, or mixed with alumina powder or silica powder, or kneaded with ethyl silicate or alcohol of one or more of alumina powder, silica powder, and zirconia powder. This method uses the outer skin as a heat transfer medium to increase the heat dissipation effect of the heat drawn from the heating wire to the surface side through the fiber layer portion, and to reduce the heat generation temperature of the heating wire and the fiber molded body. The temperature difference with the outside temperature of the heating wire is kept small, and the thermal deformation of the heating wire is suppressed by the outer skin, thereby preventing the fiber molded body from falling off locally.

Hereinafter, the present invention will be explained in detail based on the drawings showing embodiments thereof.

In Fig. 1, 1 is an inorganic fiber molding layer that constitutes a heat-generating molded body, and this is made by adding a small amount of inorganic or organic binder to heat-resistant inorganic fibers such as ceramic fibers and alumina fibers and molding them into a plate shape. On one side in the thickness direction of the plate-shaped fiber molded layer 1, there is a heating wire 3 covered with an outer skin 2 made of a material that is hard, heat resistant, and has relatively good heat conductivity.
is buried.

The material for the outer skin 2 covering the heating wire 3 may be, for example, a mixture of ceramic fiber short fibers and a fire-resistant inorganic binder mixed with water, or a material to which alumina powder or silica powder is added.
Alternatively, a material obtained by kneading alumina powder, silica powder, zirconia powder, etc. with ethyl silicate, alcohol, etc. is suitable.

In the illustrated example, the sheathed heating wire 3 covered with the sheath 2 is buried so that a part thereof is exposed on the surface of the fiber molded body, but this is buried as close as possible to the surface of the molded body. The whole part may be buried.

The fibrous heat-generating molded article having the above structure can be easily obtained, for example, by the following method.

That is, as shown in FIGS. 2 and 3, the sheathed heating wire 3 is held on one side of a mold 4 having air permeability such as a mesh plate by appropriate means, and the mold 4 is
is placed immersed in a tank 6 containing a fiber dispersion 5 made by adding heat-resistant inorganic fibers, a small amount of binder, and water, and is passed through a suction pipe 7 that opens into the tank 6 to remove the outer skin. When a suction force is applied to the side of the mold surface where the heating wire 3 is not located, fibers adhere and accumulate on the side of the mold surface where the heating wire 3 with the outer covering is supported, so that the deposited layer 8 covers the heating wire 3 with the outer covering and When the predetermined thickness is reached, the mold 4 is lifted out of the dispersion liquid,
By removing the fiber deposited layer from the mold and drying it, a fiber molded layer in which sheathed heating wires are embedded is obtained. In addition, in the example, the outer skin 2
indicates that the heating wire is coated in advance.

According to the above manufacturing method, the heating wire with a sheath can be buried at the same time as forming the fiber layer, so the embedding work of the heating wire with a sheath is easy, and the heat-resistant inorganic fiber and the binder are uniformly mixed. It is possible to obtain a heat-generating molded body made of inorganic fiber for an electric furnace and having a homogeneous integral structure.

Another method of covering the heating wire 3 with the outer sheath 2 is to leave a cavity in the part where the heating wire 3 not covered with the outer sheath is buried in the step of forming the fiber deposit layer 8, and to fill it with the above-mentioned method. Materials can also be packed or poured into the shell and allowed to dry and harden.

In the fibrous heating molded body constructed as described above, since the heating wire 3 is covered with the outer skin 2 made of a hard heat conductive material, this outer skin acts as a heat transfer medium and conducts electricity. The heat dissipation effect of the heat drawn out to the surface side of the heating wire 3 through the fiber layer portion is significantly enhanced.

In addition, due to the above-mentioned good heat dissipation effect, the temperature difference between the heat generation temperature of the heating wire and the temperature outside the molded body becomes small, so it is possible to prevent the heating wire from overheating and prevent early deterioration of the fibers around the heating wire. The useful life of the molded body can be extended accordingly.

Furthermore, in the case where the heating wire 3 is covered with the above-mentioned hard outer skin 2, the outer covering suppresses the deformation of the heating wire that occurs when the temperature rises and falls, and the fiber layer is prevented from falling off locally. It is also possible to reliably prevent an inconvenient phenomenon in which a part of the heating wire protrudes outside the molded body.

As described above, according to the present invention, in a device in which a heating wire is embedded in one side of a fiber molded layer formed of inorganic fibers to a required thickness, the heating wire is hard and has heat resistance and heat conductivity. This outer skin increases the heat dissipation effect in which the heat of the heating wire is drawn out through the fiber layer, and also prevents the fiber layer from falling off due to thermal deformation of the heating wire. Therefore, the heat-generating molded article made of inorganic fibers for electric furnaces according to the present invention can be applied to heat-generating wall bodies such as the furnace walls of electric furnaces to maximize its properties. It is demonstrated in

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway perspective view of a heating molded body made of inorganic fiber for electric furnaces showing an embodiment of the present invention, Fig. 2 is a vertical side view of the manufacturing equipment thereof, and Fig. 3 shows a heating wire with a sheath attached. FIG. In the drawings, 1... Inorganic fiber molded layer, 2... Outer skin, 3... Heating wire, 4... Mold, 5... Fiber dispersion, 6... Tank, 7... Suction pipe, 8... Deposition layer. It is.

Claims (1)

[Scope of Claims] 1 A heating wire is embedded in one side of a fiber molded layer formed by molding inorganic fibers to a required thickness, in which the heating wire is made of short fibers of ceramic fiber having heat resistance and heat conductivity, and a fire-resistant ceramic fiber. An outer shell made of a material made by kneading a natural inorganic binder with water, or adding alumina powder or silica powder thereto, or a material made by kneading one or more of alumina powder, silica powder, or zirconia powder with ethyl silicate or alcohol. A heat-generating molded article made of inorganic fiber for electric furnaces, characterized by being coated with. 2. The heating molded body made of inorganic fiber for an electric furnace according to claim 1, wherein the heating wire with a sheath is buried so that a part thereof is exposed outside the fiber layer.