JPH0141002B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a flexible linear temperature sensing wire in which a conductor for an inner wound electrode, a polymer temperature sensor, and a conductor for an outer wound electrode are sequentially provided on a core thread, and is particularly applicable to electric carpets. The present invention relates to long temperature detection wires used in large heating devices such as the following. Structure of conventional example and its problems This type of temperature sensing wire called a flexible linear plastic thermistor using a polymer temperature sensitive body is
Widely used in surface heating devices such as electric blankets and electric carpets. FIG. 1 shows the structure of this temperature detection line. 1 is a core thread, 2 is an inner-wound electrode conductor spirally wound around the core thread, 3 is a polymer temperature sensitive layer coated on the outside,
Reference numeral 4 designates an outer electrode conductor wound spirally around the outside thereof, 5 an insulating outer cover, and 6 an adhesive coating layer. FIG. 2 shows a block diagram of a temperature control circuit using the above temperature detection line. 7 shows the temperature detection line, which is connected in series with the resistor R _S and connected to the power supply 8.
Divides AC100V. 9 is a discharge tube, such as a neon lamp, connected in parallel to the detection line. 10 is a heater, 11 is a power control circuit such as a thyristor, and 12 is a temperature control circuit inserted between the neon lamp 9 and the gate of the power control circuit 11. When the temperature is low, the impedance of the polymer thermosensitive element is high, so the temperature control circuit 12 is activated by lighting the neon lamp connected in parallel to the detection line.
The heater 10 is activated by the power control circuit 11 as a trigger.
is energized. When the temperature rises due to the heat generated by the heater and reaches the set temperature, the impedance of the detection wire decreases and the voltage applied to it becomes less than the peak value of the neon lamp's discharge starting voltage, so the neon lamp turns off and power control is activated. The circuit turns off and power to the heater stops. In this way, the temperature is adjusted to the set temperature. The temperature detection wire has a double winding structure as shown above.
Depending on the size of the heating device and the pattern of the heater,
Used at appropriate length. This temperature detection line detects the average temperature of the installed heating equipment,
Since the polymer thermosensitive material, which is a thermistor material, is arranged in parallel in the length direction, it has the ability to preferentially pick up local overheating as a signal and suppress the local overheating temperature to a minimum. Conventionally, this type of temperature detection wire has been developed mainly for electric blankets, but with the advent of electric carpets and their increasing size, the use of long wires is increasing.
In this case, the impedance between the terminals of the temperature detection line decreases in inverse proportion to the length, making it difficult to use in terms of circuitry. In other words, for the purpose of voltage division for temperature setting and current limitation to prevent thermistor breakdown (burning due to self-heating), a resistor R _S is connected in series as shown in Figure 2, but in order to prevent thermistor breakdown, , it is necessary to limit the current flowing through the temperature detection wire by setting the low resistance R _S to approximately 20KΩ or more. For example, the neon lamp 9 blinks (discharge starting voltage 68V _peak ).
When using , the impedance and resistance R _S of the temperature detection wire at approximately 50 to 60℃ are exactly equal to the power supply of 100V.

[Formula] must be set to divide the voltage to 52V. Therefore, in this case, there is a restriction that the long temperature detection wire must be 22KΩ or more (20KΩ×52/48) at approximately 50 to 60°C. OBJECTS OF THE INVENTION Under the above-mentioned limitations, an object of the present invention is to provide a temperature sensing wire suitable for use as a long object without causing thermistor breakdown. Structure of the Invention The temperature sensing wire of the present invention has a structure in which an inner-wound electrode conductor, a polymer temperature-sensitive body, and an outer-wound electrode conductor are sequentially provided concentrically on the axle thread, and as the polymer temperature-sensitive body, 60
℃, impedance at 60Hz is 5×10 ⁸ ~3
×10 ⁹ Ω·cm, and the thermistor B constant at 60 to 100°C is 8000〓 or more. To explain in more detail, the temperature detection line is constructed as shown in FIG. 1, and its electrical equivalent circuit is approximated by a parallel circuit of a resistor R and a capacitor C. The values of R and C are determined by the characteristics (specific resistance ρ, dielectric constant ε), thickness, and electrode structure of the polymer temperature sensitive body. The polymer thermosensor used in the present invention is suitably an ion conductive polymer thermosensor made by adding an ionic substance to an insulating polymer, and is designed to have the characteristics as shown in FIG. Note that Z _SP is volume specific impedance, ρ is specific resistance, and X _C is capacitive reactance. In other words, it is a general commercial frequency. 60Hz
The specific volume impedance Z _SP at 60℃ is 5
If a polymer thermosensitive material with a resistance of ×10 ⁸ to 3 × 10 ⁹ Ω・cm is used, the temperature detection wire shown in Figure 1 will have a resistance of about 3 per 30 m at 60°C, although it depends on the winding structure. ×10 ⁴ ~
It shows an impedance of 2×10 ⁵ Ω. This is because the impedance Z (Ω) value per meter of the temperature detection line varies depending on its structural specifications, but it is approximately 1/500 of the volume specific impedance Z _SP (Ω cm) value of the polymer thermosensitive material. be. Therefore, the impedance Z per 30m is Z _SP・1/500・1/303×10 ⁴ ~2
It becomes ×10 ⁵ Ω. In this case, if the resistance R _S shown in Figure 2 is approximately 2.8×10 ⁴ to 1.8×10 ⁵ Ω, then the power supply
Since 100V can be divided into 48V and 52V, the flashing of the neon lamp 9 can be used. Note that this resistance
The value of R _S of approximately 2.8×10 ⁴ to 1.8×10 ⁵ Ω exceeds the minimum resistance value of 22 KΩ to prevent thermistor breakdown, so there is no problem. Next, the impedance Z of the temperature detection line per 300m is _ZSP・1/500・1/3003×10 ³ to 2×10 ⁴ Ω. In this case, the resistance R _S is approximately 2.8×10 ³ to 1.8×10 ⁴ Ω
By doing so, the voltage of 100V can be divided into 48V and 52V, and the blinking of the neon lamp 9 can be used. In this case as well, the value of the resistor R _S is approximately 2.8×10 ³ ~
There is no problem because 1.8×10 ⁴ Ω is more than the 22KΩ required to prevent thermistor breakdown. As mentioned above, the protective resistance of the thermistor needs to be 2×10 ⁴ Ω or more in order to prevent thermistor breakdown due to local heating.
It can be said that general-purpose heating equipment with a maximum set average temperature of approximately 60°C exhibits the optimal impedance;
Since the thermistor B constant is as high as 8000 or more, local heating can be kept low. Especially when switching temperature signals using neon lamps, the
The temperature sensing line of the present invention is suitable because it operates at 60V (V _peak = 65-80V). In the case of the present invention, the impedance of the temperature detection wire of the present invention can be lowered to approximately 22KΩ (when using a neon tube) at the maximum set temperature, so as mentioned above, the temperature detection wire of the present invention can be reduced to 30KΩ.
In principle, it is possible to use it over a wide range of up to 300 m. In this case, the longer the length, the more
Naturally, the resistance of the winding electrode must be set to be low. Examples of the ion conductive composition which is a polymer temperature sensitive material used in the present invention include polyvinyl chloride compositions, polyvinyl chloride vinyl acetate copolymers, polyamide compositions, etc. Among them, polyvinyl chloride compositions or their Copolymer compositions are suitable, perchlorate is preferred as the ion carrier, and pentaerythritol esters such as pentaerythritol and dipentaerythritol are preferred as the plasticizer because of their excellent thermal stability. In addition, when the temperature detection wire of the present invention is used to construct a planar heating device such as a carpet, thermal pressure may be applied by a heat press, etc., and as a result of consideration from this point of view or from the point of view of load resistance. By setting the average degree of polymerization of polyvinyl chloride to 1800 or more, it was possible to reduce heat deformability. The temperature detection wire of the present invention can be said to be of a high impedance type compared to temperature detection wires generally used on the market, and is suitable for long length use. The characteristics of the impedance-temperature characteristics are that the contribution of the C component is large in the low temperature range (below 60°C), the contribution of the R component is large in the high temperature range (above 60°C), and the B constant of the thermistor is also large. EXAMPLE DESCRIPTION Perchlorate Volume-specific impedance containing 0.5% by weight and 18% by weight of dipentaerythritol ester
Z _SP is 4.5×10 ⁹ Ω・cm (30℃) at 60Hz, 8×10 ⁸ Ω・
cm (60°C) and 3×10 ⁷ Ω・cm (100°C), as shown in Figure 1, an inner-wound stainless steel wire 2 ( A foil (width: 0.32 mm) is wound with a pitch of 0.7 mm, and the polymer temperature-sensitive layer 3 is coated in a tubular shape with a diameter of 1.3 mm using a wire making extruder.
Wrap it with 0.75mm, add a spacer made of polyester film (thickness 15μm), and wrap soft polyvinyl chloride 5 and polyethylene 6 sequentially to 0.5mm and 0.3mm.
The temperature detection line was made by tubing to a thickness of . When we measured the impedance of this detection line, it was 9×10 ⁶ Ω per meter at 60Hz (30℃).
They were 1.6×10 ⁶ Ω (60°C) and 6×10 ⁴ Ω (100°C).
Thermistor B constant with this characteristic is 5800 at 30 to 60℃
〓, 10200〓 at 60~100℃. When an electric carpet for 4.5 tatami mats was constructed using this 56m detection wire, the impedance of the detection wire at 60℃ was 30KΩ.When the maximum set temperature was set to 60℃ using the circuit shown in Figure 2, the neon tube (discharge starting voltage V _peak = 68V), R _S =
It was set to 35KΩ. When this carpet was locally covered with urethane foam measuring 20 x 20 cm to keep it warm, the heated area under the urethane foam showed a low temperature of approximately 84°C, confirming stability against local overheating. In addition, when we measured the length dependence of the current value of this temperature detection line, we found that the current value was proportional to the length up to a long length as shown in Figure 4.
Thermistor B constant at ~60℃ is 9000〓, 60℃
The impedance was 3.3×10 ⁵ Ω), which showed excellent long-length suitability. Effects of the Invention According to the present invention, the following effects can be obtained. (1) Due to its high impedance per length, it is suitable for long lengths and can be easily applied to large-area heating devices. (2) Because the impedance of the polymer thermosensitive body is high,
The resistance difference with the winding electrode is large, the voltage drop in the length direction of the detection wire is small, and the efficiency of overall temperature detection is improved. (3) It has a high thermistor B constant at temperatures above 60°C, and has high safety performance against local overheating. (4) There is no self-heating and thermistor breakdown does not occur even if the length is long.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the structure of the temperature detection line, Fig. 2 is a block diagram of a temperature control circuit using the same detection line, Fig. 3 is a diagram showing the temperature characteristics of the polymer thermosensitive body of the present invention, FIG. 4 is a comparison diagram of the length dependence of the current value of the temperature detection line. DESCRIPTION OF SYMBOLS 1... Core yarn, 2... Conductor for inner wound electrode, 3... Polymer temperature sensitive body, 4... Conductor for outer wound electrode, 5... Outer skin.

Claims (1)

[Claims] 1. A temperature sensing wire in which an inner-wound electrode conductor, a polymer temperature-sensitive body, and an outer-wound electrode conductor are sequentially arranged concentrically on a core thread, and the specific volume impedance of the polymeric temperature-sensitive body is 60°C; 5×10 ⁸ to 3× at 60Hz
10 ⁹ Ω・cm, and a thermistor B constant of 8000〓 or more at 60°C to 100°C.