JPS6340877Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of an electric heating device for heating liquids such as heavy oil.

In order to improve the fluidity of heavy oil storage tanks, storage tanks are heated, but electric heating devices, which are easy to control temperature and easy to maintain, are being adopted in place of conventional hot water and steam.

There are two types of electric heating devices: one in which the heating device is wrapped around the storage tank, and the other in which the heating device is inserted directly into the storage tank, but the latter is superior in terms of thermal effects.

Conventionally, this direct insertion type heating device uses an inorganic insulated cable, which is inserted into a protective tube and the gap is filled with inorganic filler such as magnesium oxide or alumina. In some cases, a large number of small-diameter protection tubes were provided, an inorganic insulated cable was inserted into each, and the gap formed by the small protection tube and the outer protection tube was filled with an inorganic filler.

However, the former has the disadvantage that the inorganic insulated cable itself cannot be replaced in the event of a failure because it is filled with an inorganic material.

On the other hand, although the latter is easy to replace, there is a gap between the inorganic insulated cable and the small protective tube, and when using an inorganic insulated cable that reaches high temperatures (over 200°C), there is a risk of oxidation deterioration. .

Also, both are filled with inorganic fillers,
Inorganic fillers have considerably better thermal conductivity than air, but they are not perfect conductors of heat, and have a high thermal resistance, which necessitates using inorganic insulated cables at high temperatures, which shortens their lifespan. It was hot.

Furthermore, inorganic fillers have a high specific gravity (for example, alumina is 3.9), making the heating device heavy and difficult to handle.Additionally, powder filling processing of inorganic fillers is not easy, and processing costs are a disadvantage. It was hot.

An object of the present invention is to provide an electric heating device that eliminates the drawbacks of the prior art described above, extends the life of an inorganic insulated cable, and improves ease of handling. That is, the gist of the present invention is that an inorganic insulated cable is wound around a cylindrical support member, a metal protection tube houses the cable, and a metal protection tube is installed in the gap formed by the cable and the protection tube. The electric heating device is characterized in that it is constructed of a metal structural material having a diameter slightly smaller than that of the protective tube.

Next, an embodiment of the present invention will be further explained with reference to the accompanying drawings. FIG. 1 shows an insertion type electric heating device applied to an oil tank 1, in which a heating device 2 is inserted into a storage tank 1. The storage tank bottom or storage tank wall is used as a support 3.

FIGS. 2 and 3 show an enlarged cross section of the heating device 2, and 4 is an internal metal tube, around which an inorganic insulated cable 5 is wound.

Reference numeral 6 designates a metal structural material on its outer periphery that serves as both a protective layer and a heat medium, and 7 designates a metal protective tube having an inner diameter slightly larger than this metal structural material 6, which houses the metal structural material 6 and has a lid at its tip. It is sealed with an 8.

Further, a flange 9 is attached to the fundamental part corresponding to the storage tank attachment side, and is tightened and fixed to the storage tank side wall with bolts and nuts through a gasket.

On the other hand, the inorganic insulated cable 5 terminal is taken out from the storage tank attachment outer flange portion, terminal processed, and
A power supply line 1 placed in an explosion-proof junction box 10 and connected from the outside
1 is connected.

Here, a steel pipe or an aluminum pipe is used as the internal metal pipe 4, but it is not limited to a pipe as long as it acts as a support material for winding the inorganic insulated cable 5. As the metal structural material 6, a shaped material such as aluminum casting is used.

The winding pitch of the inorganic insulated cable 5 is arbitrarily determined depending on the required amount of heat.

A steel pipe is used as the outermost protective tube 7, and its inner diameter is slightly larger (10 mm or less) than the metal structural material 6, making it easy to assemble and remove.

As the inorganic insulated cable 5, a two-core or three-core cable is used.

The external protection tube is not limited to steel pipes, but may also be made of plastic such as heat-resistant vinyl pipes.Although the heating device is cylindrical in shape for ease of manufacture, it is not limited to cylindrical shapes; cross-sections may also be oval, rectangular, etc. good.

Furthermore, the heating device may be used not only for storage tanks, but also for preventing freezing of soil and heating solid materials, and the present application is not to be construed as being limited by this example.

This embodiment, which is constructed in this way, has good thermal conductivity because aluminum is used as the metal structural material, and can efficiently transfer the amount of heat from the inorganic insulated cable.The thermal conductivity of aluminum is 2.5Kcal/mh℃. On the other hand, since the thermal conductivity of conventional alumina or magnesium oxide is about 0.5 Kcal/mh°C, the thermal conductivity is about 5 times better.

Furthermore, since it is a metal structural material, it is easier to assemble and disassemble compared to the difficulty of filling with conventional inorganic fillers, and in the unlikely event of a failure, it is possible to pull out just the heater part and replace it. .

Additionally, aluminum has a low specific gravity, making it lightweight.
Also, because of its good thermal conductivity, the thermal resistance of the protective layer is low.
The heater can be used at a lower temperature.

In other words, if a conventional inorganic filler is used for protection, a heater of about 20Kw with this heat medium will heat up to 100℃.
~150℃ temperature difference occurs, whereas 20~30℃ temperature difference occurs.
It is possible to make a temperature difference of ℃, which can significantly extend the life of the heater.

As explained above, according to the present invention, it is possible to provide an excellent electric heating device that has a long lifespan for inorganic insulated cables and is easy to handle, and its practical value is extremely large. There is something.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing an embodiment of the electric heating device of the present invention used for heating an oil tank, Fig. 2 is a cross-sectional explanatory diagram showing an embodiment of the inventive heating device, and Fig. 3 is an explanatory diagram of the device. It is a longitudinal cross-sectional explanatory view. 1: storage tank, 2: heating device, 3: support material, 4: internal metal tube, 5: inorganic insulated cable, 6: metal structural material, 7: metal protection tube, 8: lid, 9: flange,
10: Explosion-proof junction box, 11: Power supply line.

Claims (1)

[Scope of utility model registration request] An inorganic insulated cable wrapped around a cylindrical support member, a metal protection tube housing the cable, and a metal structure with a diameter slightly smaller than the protection tube provided in the space formed by the cable and the protection tube. An electric heating device characterized in that it is made of a material.