JPS58124B2 - temperature sensitive wire - Google Patents

Description

[Detailed description of the invention] The present invention can be installed along an electric cable or bus duct,
This invention relates to improvements in temperature-sensitive wires that detect localized heating.

Such temperature-sensing wires are made by connecting 1,000-row two-conductor wires that are already mutually insulated at predetermined intervals in the length direction, and as temperature-sensing elements, thermistors whose DC resistance suddenly changes at a specific temperature are connected in parallel. A structure with this structure was used.

However, because the operating temperature of the thermistor, that is, the temperature at which the DC resistance rapidly decreases with temperature rise, is limited to a value specific to the material, it has been difficult to obtain a temperature-sensitive wire with a desired operating temperature.

Furthermore, when the temperature drops, the signal returns to its original high resistance state, making it difficult to check whether the receiving device is malfunctioning.

The present invention provides a temperature-sensitive electric wire that can freely set the operating temperature by using a composite temperature-sensing element consisting of a heat-sensitive thyristor and a combination element as a temperature-sensing element.The configuration thereof will be explained below with reference to the drawings. do.

FIG. 1 is a wiring diagram of a conventional temperature-sensitive electric wire, in which temperature-sensing elements 2 made of semiconductors, that is, thermistors 3, are connected in parallel to three parallel conductors 1a and 1b at predetermined intervals.

The predetermined interval varies depending on the object of temperature measurement or the possible cause of overheating, but is usually several tens of cm to 10 m.

A receiver is connected to the three conductors at one end of the temperature-sensitive wire, and temperature is monitored by applying voltage from the built-in DC power supply and measuring the insulation resistance between the three conductors.

FIG. 2 is a side view showing a specific connection structure of a conventional temperature sensing element, in which two lead wires 10 from the temperature sensing element 2 are connected to three parallel conductors 1a and 1b of the temperature sensing electric wire 1. .

In FIG. 2, 11 is the insulator of the conductor, and 12 is the cable jacket.

FIG. 3 is a specific wiring diagram of the temperature sensing element used in the temperature sensing electric wire according to the present invention, in which the temperature sensing element 2' is anode A,
It is composed of a heat-sensitive thyristor 4 having three terminals, a cathode K and a gate G, and combination elements 5 to 7.

A heat-sensitive thyristor is a type of temperature-sensitive switch that changes from an off state to an on state (this is called a turn-on) when the temperature exceeds a set temperature.As long as the current flowing through it maintains the holding current, it remains on even if the temperature drops. This switch function and the continuation of the on state are two points that differ from conventional thermistors.

In Fig. 3A, when the combination element is a resistor 5, which is connected between the anode and the gate of the three terminals, and when the resistor 5' is connected between the cathode and the gate, C shows the case where the combinational element is a diode 6, which is connected between the cathode and the gate, and 2 shows the case where the combinational element is the thermistor 7, which is connected between the cathode and the gate.

Conventionally, a thermistor was used as a single temperature sensing element, and the operating temperature thereof was a temperature specific to the thermistor material, making it difficult for a temperature-sensitive wire designer to make the wire have the desired operating temperature.

In the temperature-sensitive electric wire according to the present invention, the temperature-sensing element used therein is a combination of a heat-sensitive thyristor and a combination element, and by changing the characteristic values of the combination element, the operating temperature can be controlled within a certain range, for example, 60°C. The temperature can be set freely within a range of 100°C to 100°C.

These characteristic values are the resistance value of the resistor 5 or 5' in FIG.

Figure 4 shows the relationship between the resistor 5 and the turn-on temperature of the heat-sensitive thyristor, that is, the operating temperature of the humidity sensing element in the case of Figure 3 A. For example, if you want the turn-on temperature to be 100°C, the value of the resistor 5 is You can set it to Ω.

FIG. 5 is a wiring diagram showing an example of a temperature-sensitive electric wire according to the present invention.
As shown in FIG. 3A, a plurality of δ temperature sensing elements 2' are connected in parallel to three parallel conductors 1a' and 1b'.

In the figure, in actual use, conductor 1b'
It is necessary to apply a positive potential to the side.

Temperature sensing elements 2' must be of the same type for all temperature sensing wires, for example, in the case of FIG. 3A, all temperature sensing elements must have the same configuration.

However, it is possible to change the characteristic values of the combined elements.

FIG. 6 shows an example of how the temperature-sensitive electric wire according to the present invention is attached.

In the temperature-sensitive electric wire shown in the figure, the characteristic values of the combination elements are different within a single length of the temperature-sensitive electric wire.

That is, in the figure, a power cable 8 and a bus duct 9 are installed at the same installation location, and a single-length temperature-sensitive electric wire is attached to them.

In an electric cable, the conductor is coated with a thick insulating layer and an anti-corrosion layer on top of it, so its thermal resistance is high, so it will sense when the conductor reaches its permissible humidity of, for example, 80°C. In this case, the operating temperature of the humidity sensing element 13 of the temperature-sensitive electric wire 1' attached to the cable surface is set to a low humidity of, for example, about 60°C.

On the other hand, bus ducts are generally not coated with insulation layers, etc.
The operating temperature of the temperature sensing element 14 of the temperature sensitive electric wire attached to the surface is set to the permissible temperature of the bus duct, for example, 90°C.

In this way, it becomes possible to monitor the temperature of different types of cables or cables with different permissible humidity using one single length of temperature-sensitive wire.

FIG. 7 is a perspective view showing an example of a molded body of a temperature-sensing element of a thermo-sensitive electric wire according to the present invention, in which a resistor 5 is connected between the anode A of the heat-sensitive thyristor 4 and the gate 0 by a connector 15;
It is integrally molded with the heat-sensitive thyristor using insulating resin.

Only the terminal 18 from the anode and the terminal 19 from the cathode are exposed from the molded body 17.

Note that 16 in the figure is an insulated lead wire.

Furthermore, it is important that no cavities are formed in the molded body 17.

Although it is not always necessary to form a molded body like this, since heat-sensitive thyristors and combination elements are small parts of 1 cm or less, it is better to connect the combination element to the heat-sensitive thyristor and integrate it in advance for better connection to the wire conductor. This is preferable because it is easy to work and there is no fear that the combination element will become disconnected during handling of the temperature-sensitive wire.

In the above explanation, all electric wire conductors were explained as three parallel conductors, but large currents often flow through the electric cable or bus duct to which they are installed, and in that case, there is a risk that induced voltage may occur in the temperature-sensitive electric wire. be.

In such cases, the influence of induction can be reduced by twisting the three conductors together.

As described above, the temperature-sensitive electric wire according to the present invention has the following effects.

(1) Since the temperature sensing element is composed of a heat sensitive thyristor and a combination element, the operating temperature of the temperature sensing element can be set by selecting the characteristic values of the combination element. can get.

(2) Even if a conventional temperature-sensitive wire using a thermistor operates, it is difficult to check whether it is a malfunction of the receiving device if the temperature drops immediately, but the heat-sensitive thyristor of the present invention is used. This temperature-sensitive electric wire remains on even if the temperature immediately drops after being turned on, so it is possible to check for malfunctions and is highly reliable.

(3) - By setting the characteristic values of the combined elements in the temperature sensing elements connected to it to different values within a single length, temperature sensing elements having different operating flow rates depending on the location within the single length are created. - It is possible to monitor the hot water temperature of a plurality of power cables having different monitoring humidity using a single length of temperature-sensitive electric wire.

(4) By integrating the combination element after connecting it to the heat-sensitive thyristor, it becomes easier to connect the temperature-sensing element to the conductor, and the connection of the combination element can be removed while the humidity-sensing wire is attached to the power cable. Fear disappears.

[Brief explanation of the drawing]

Figure 1: Connection diagram of a conventional temperature sensing electric wire, Figure 2: A perspective view of the connection structure of a conventional temperature sensing element, Figure 3: Connection diagram of a temperature sensing element according to the present invention, Figure 4: Between the anode and the gate. Fig. 5 is a wiring diagram of an example of a moisture-sensitive electric wire according to the present invention, Fig. 6 is an installation example of a temperature-sensitive electric wire according to the present invention, Fig. 7 is a diagram of the relationship between the resistance of the heat-sensitive thyristor and the turn-on hot water temperature of the heat-sensitive thyristor. FIG. 3 is a printed view of a molded body of a temperature sensing element of a temperature sensing electric wire. 1.1'...Temperature-sensitive electric wire, 2,2'...Temperature-sensitive solar element, 1a, 1b...Parallel two conductors, 4...Heat-sensitive thyristor,
3...Thermistor, 6...Diode, 5゜5'...Resistor, 7...Thermistor, A...Anode, K...Cathode, G...
...Gate, 8...Electric cable, 9...Bus duct, 1
0...Lead wire, 11...Insulator of conductor, 12...Cable jacket, 13゜14...Temperature sensing element, 15...Connector, 16...Insulated lead wire, 17...Insulating resin molding Body, 18...anode terminal, 19...cathode terminal.

Claims (1)

[Scope of Claims] 1. A temperature-sensing wire in which a plurality of temperature-sensing elements are connected in parallel to three conductors at predetermined intervals, wherein the temperature-sensing elements are composed of a heat-sensitive thyristor and a combination element. . 2. By setting the characteristic value of the combined element in a specific temperature sensing element among the plurality of humidity sensing elements connected in parallel to the three conductors to be a different value from the characteristic value of the combined element in the other humidity sensing elements. 2. The temperature-sensitive electric wire according to claim 1, wherein the specific temperature-sensing element has an operating humidity different from the operating temperature of the temperature-sensing element of the pond. 3. A temperature sensing element in which the combination element connected to the terminal of the heat sensitive thyristor is integrally molded with the heat sensitive thyristor using an insulating resin, and only the two terminals from the anode and cathode of the heat sensitive thyristor are exposed from the molded body. The temperature-sensitive electric wire according to claim 1 or 2, characterized in that the wire is connected.