JPS6231995Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a heater wire using conductive rubber or plastic as a heating element.

2. Description of the Related Art Heater wires that use conductive rubber or plastic as a heating element are known as heater wires used for various purposes.

As shown in Fig. 1, this heater wire is covered with two electrodes 1 and 2 made of a good conductor such as annealed copper and a heating element 3 made of conductive rubber or plastic formed into a plate. It has a structure in which the outside is wrapped with an insulator 4.

The heater wires shown above are usually several meters to several meters long.
They are often used in lengths of 10 m, and when electricity is applied from one end of one electrode, for example, a voltage drop phenomenon occurs and the amount of heat generated decreases in the length direction.

In other words, when a voltage is applied from one end of one electrode, a distributed constant circuit forms between the electrode and the heating element, and the voltage between the electrodes becomes smaller as the tip approaches, and therefore the amount of heat generated per unit length decreases as the tip approaches. rise will be less.

The relationship between the length of the heater wire and the voltage change is shown in FIG. 3, and it is known that the longer the heater wire is, the lower the voltage will be, as evidenced by the distributed constant circuit equation.

The above phenomenon is extremely inconvenient when it is desired to make the surface temperature and calorific value uniform over the entire length of the heater wire.

In order to make the surface temperature and calorific value uniform over the entire length of the heater wire, as shown in Figure 2, both electrodes 1 and 2 should be
The voltage must be applied from opposite ends of the

For this purpose, it is necessary to separately install the lead wires 5 at the same time as the heater wires, which poses a problem in that much labor and time are required for the installation work.

This idea was made in view of the above-mentioned problems, and aims to provide a heater wire that can easily apply electricity to both ends of the electrode and can generate a uniform amount of heat in the length direction. purpose.

Below, Figures 4 to 7 show examples of this invention.
This will be explained based on the diagram.

FIGS. 4 and 5 show a first example of this invention using a single lead conductor.

As shown in FIG. 4, the heater wire 11 wraps the outside of the heating element 14, which has electrodes 12 and 13 embedded on both sides, with an insulator 15.
It has a structure in which a lead conductor 16 is laid on one side edge of the heater wire 4, and the conductor 16 is provided parallel to the electrodes 12 and 13 over the entire length of the heater wire.

To use the heater wire, as shown in FIG. 5, the lead conductor 16 and the electrode 13 are connected at the end of the heater wire 11, and the power source is connected to the electrode 12 and the lead conductor 16 at the start end of the heater wire. The lead conductor 16 is installed on the insulator 15 in advance, and can be applied to both electrodes 12 and 13 from the ends in different directions without dropping the voltage. A constant calorific value and surface temperature can be obtained.

6 and 7 show a second example of this invention using two lead conductors.

The heater wire 11 of this second example has a structure in which lead conductors 16 and 17 are laid on both sides of a heating element 14 within an insulator 15, as shown in FIG.

As shown in FIG. 7, the heater wire of the second example has one electrode 12 and a lead conductor 16 at the start and end ends of the heater wire 11, and the other electrode 13 and a lead conductor 17 at each end. The electrodes 12 and 13 are connected to a power source on the starting end side.

By using the two lead conductors 16 and 17 and connecting both ends to the electrodes 12 and 13, the potential difference between the electrodes becomes approximately equal over the entire length of the heater wire 11, preventing voltage drop. Surface temperature and calorific value become uniform.

In any case, it is desirable for performance that the lead conductor has a lower conductor resistance than the electrodes 12 and 13, and the electrodes 12 and 13 are made of a good conductor such as annealed copper. Use a good conductor with a large cross-sectional area.

The heating element 14 is made of a PTC composition such as cross-linked polyolefin mixed with conductive carbon,
As the insulator, it is preferable to use plastic such as polyolefin or rubber.

As described above, according to this invention, in a lead wire in which the outer periphery of a heating element in which two electrodes are buried in parallel is covered with an insulator, the lead conductor inside the insulator is laid parallel to the electrodes. , it is possible to apply electricity to both ends of the electrode without the need for installation of separate lead wires for the heater wire, even in the case of long heater wires that are used for heat insulation or freezing prevention by wrapping around pipes, etc. There is no voltage drop in the length direction, and a uniform amount of heat is obtained.

Furthermore, since there is no need to separately install lead wires, the installation work can be greatly facilitated.

[Brief explanation of the drawing]

Figure 1 is a longitudinal sectional front view showing a conventional heater wire.
Fig. 2 is a plan view showing the same energized state as above, Fig. 3 is a graph showing the relationship between length and voltage in a conventional heater wire, Fig. 4 is a longitudinal sectional front view showing the first example of this invention; FIG. 5 is a plan view showing the same energized state as above, FIG. 6 is a longitudinal sectional front view showing a second example of this invention, and FIG. 7 is a plan view showing the same energized state. 11... Heater wire, 12, 13... Electrode, 1
4... Heating element, 15... Insulator, 16, 17...
Conductor for leads.

Claims (1)

[Claims for Utility Model Registration] (1) Two electrodes are laid in parallel on a heating element formed using a conductive composition, and the outer periphery of the heating element is insulated by a heater wire covered with an insulator. A heater wire characterized by having a lead conductor laid inside the body parallel to the electrode. (2) The heater wire according to claim 1 of the utility model registration, characterized in that two conductors are installed on both sides sandwiching the heating element. (3) The heater wire according to claim 1 or 2, wherein the conductor is formed using a material having a lower conductor resistance than the electrode.