JPH028497Y2 - - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to an improved snow-resistant electric wire.

Sleeves made of ferromagnetic material are attached to the outer circumference of the electric wire at appropriate intervals, and the ferromagnetic sleeve is heated by electromagnetic hysteresis due to electricity, and the heat melts and removes snow that has fallen on the wire. Snow electric wire is known.

However, in this case, the ferromagnetic sleeve not only generates heat when it snows, but also constantly generates heat even when the temperature is high, causing problems in that it unnecessarily increases conduction loss and wastes heat.

To solve this problem, it has been proposed to construct the sleeve in whole or in part from a material with a low Curie point so that it becomes magnetic only at temperatures below snowfall temperatures. However, this is an ideal theory, and the current situation is that it is difficult to find such a material, and even if it is found, the degree of magnetism will not be the desired value, and the heat generation will not be the desired value.

The present invention was developed in view of such circumstances, and its gist is that the ferromagnetic sleeve that is attached to the electric wire is divided vertically, and the thermal expansion coefficient between the divided parts is higher than that of the sleeve itself. The reason is that a non-magnetic material with a large amount of carbon is used.

This will be explained below based on a specific example.

FIG. 1 shows a sleeve 1 according to the present invention attached to an electric wire 10.
FIG. 2 is a partial sketch of a snow-resistant electric wire coated with

In this case, the sleeve 1 made of ferromagnetic material is
It consists of divided bodies 1a and 1b. Of course, this division is not limited to two divisions.

For example, it may be cut vertically in one place in a C-shape, or it may be divided into three or four parts.If the sleeve is divided into two or more parts, the sleeve is held by a spring ring, etc. It may be held by a piece (not shown).

Therefore, the divided parts of the divided bodies 1a and 1b have a third
As shown in the figure, an intervening material 2 is made of a non-magnetic material and has a coefficient of thermal expansion larger than that of the sleeve 1 itself, leaving the necessary parts of the opposing surfaces 1c and 1c at the end edges.
is interposed. The intervening substance 2 must satisfy the following intervening conditions. That is, when the temperature is higher than the snowfall temperature, the intervening material 2 having a large coefficient of thermal expansion expands, so that a gap 3 as shown in FIG. 3 is formed between the divided parts. As a result, a magnetic insulating portion is formed in the sleeve 1, so that no heat is generated. However, when the temperature falls and reaches the snowfall temperature, the intervening material contracts, the gap 3 in Figure 3 becomes zero, and the opposing surfaces 1c and 1c come into contact as shown in Figure 2. . When this happens, the sleeve 1 is integrated, and the sleeve 1 generates heat due to the magnetically induced current. The intervening conditions for the intervening substance 2 are selected so as to satisfy the above phenomenon. Finding this condition is extremely easy. More specifically, 160mm ²
Length 30mm, outer diameter attached to the outer circumference of ACSR10
A two-part sleeve 1 with an inner diameter of 24.3 mm and an inner diameter of 18.3 mm is made of pure iron, and a width of 1.5 mm is provided on one side of the opposing surface 1C.
An aluminum plate 2 with a thickness of 1 mm and a length of 27 mm is inserted into the groove of 1 mm, and when the temperature of the sleeve 1 is higher than 5°C, a gap 3 is formed on the opposing surface 1C due to thermal expansion of the aluminum plate 2. By adjusting the width of the aluminum plate 2, we were able to obtain a characteristic that generates heat only at temperatures below 5°C.

As a result, the sleeve 1 is attached to the electric wire 10.
Since the electric wire generates heat only at temperatures below the snowfall temperature, no unnecessary heat is generated as in the conventional example, and an extremely efficient snow-resistant electric wire can be provided.

[Brief explanation of the drawing]

FIG. 1 is a partial sketch of the snow-resistant electric wire according to the present invention, and FIGS. 2 and 3 are explanatory diagrams showing the behavior of the sleeve. 1: Sleeve, 2: Intervening substance, 3: Gap, 1
0: Electric wire.

Claims (1)

[Scope of utility model registration request] A sleeve made of ferromagnetic material having one or more vertical divisions is attached to the outer circumference of the electric wire,
A non-magnetic intervening material having a coefficient of thermal expansion greater than that of the sleeve itself is interposed between the edges of the divided portion so as to be held between the edges of the divided portion, leaving a required portion of the opposing surface. , the intervening state of the intervening substance is such that at snowfall temperatures, the opposing surfaces can contact each other due to its contraction, and at higher temperatures, the opposing surfaces become separated due to thermal expansion of the intervening substance. A snow-resistant electric wire constructed of