JPH076863A - Safety device for thermosensitive heating element - Google Patents

Abstract

PURPOSE:To prevent an operation temperature of a safety device from changing largely even if commercial AC electric power supply voltage is changed. CONSTITUTION:An electric current fuse CF is connected between one end of a detecting wire 4 and one end of a heater wire 2. Resistors R2 and R3 are connected in series between the other end of the detector wire 4 and the other end of the heater wire 2, and a resistor R5 and a thyristor SCR2 are connected in series between a connecting point of the resistors R2 and R3 and the other end of the detecter wire 4. Resistors R6 and R7 are connected in series between both ends of the heater wire 2, and a gate terminal of the thyristor SCR2 is connected to a connecting point of the resistors R6 and R7. A series circuit of a heater resistor R0 and a thyristor SCR1 is connected between both ends of the heater wire 2, and a gate terminal of the thyristor SCR1 is connected to the connecting point of the resistors R2 and R3, and the heater resistor R0 is joined thermally to a temperature fuse TF inserted in a main circuit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a safety device for a heat-sensitive heating element mainly used in floor heating devices such as electric carpets and electric floor heaters.

[0002]

2. Description of the Related Art As an example of a conventional safety device for a heat-sensitive heating element, the one described in Japanese Patent Publication No. 4-10196 has been exemplified. FIG. 2 shows a configuration diagram of the heat-sensitive heating wire H. The heat-sensitive heating wire H includes a core wire 1 such as a polyester yarn, a heating wire 2 made of a copper alloy spirally wound, and the heating wire 2. 2, a heat-sensitive material 3 such as vinyl chloride coated on the outside, a detection wire 4 spirally wound around the heat-sensitive material 3, and an insulating layer such as vinyl chloride coated on the outside of the detection wire 4. It is composed of 5. Also in FIG.
Shows a conventional safety device for a heat-sensitive heating element using a heat-sensitive heating wire H. A conventional example will be described with reference to FIG.

A heat-sensitive heating wire H, a commercial AC power supply AC for the heat-sensitive heating wire H, a temperature fuse TF inserted in a main circuit between the commercial AC power supply AC and the heat-sensitive heating wire H, an on / off switch SW and a thermostat. A resistor R with a high resistance value inserted between the switch TS and one end of the detection line 4 and one end of the heating line 2.
₁ , a low resistance current fuse CF inserted between the other end of the detection line 4 and the other end of the heat generation line 2, and in series between one end of the detection line 4 and the other end of the heat generation line 2. Connected resistors R ₂ , R
_3, and the resistance R _2, resistors R ₄ connected between the connection point of the R ₃ and the other end of the detection line 4, and the heating resistor R ₀ connected in series across the heating wire 2, The thyristor SCR is composed of a thyristor SCR, a gate of the thyristor SCR is connected to a connection point of the resistors R ₂ and R ₃ , and a heat generating resistor R ₀ is thermally coupled to a temperature fuse TF inserted in the main circuit. ing.

Here, when an abnormality such as disconnection of the detection wire 4, disconnection of the heating wire 2, local heating, and overall abnormal temperature rise occurs in the heat-sensitive heating wire H, it is high at both ends of the detection wire 4. Since the voltage is generated and the thyristor SCR is turned on to melt the temperature fuse TF to stop the energization, the abnormal high temperature is prevented from continuing.

[0005]

However, in the safety device using the temperature / AC voltage characteristic voltage generated between both ends of the detection line of the heat-sensitive heating wire, the temperature / AC voltage characteristic voltage is set in advance. When the temperature rises above the value, the thermal fuse is blown to stop energizing the heating wire.

The temperature generated between both ends of the detection line
As seen in the characteristic diagram (Fig. 3) showing the relationship between the AC voltage characteristic voltage and the commercial AC power supply voltage, the temperature at the same temperature when the commercial AC power supply voltage fluctuates in the direction of decreasing
Since the AC voltage characteristic voltage also decreases in proportion to the commercial AC power supply voltage, the temperature at which the safety device operates increases as the commercial AC power supply voltage decreases. For example, when the commercial AC power supply voltage is 100 V, the temperature of the heat-sensitive heating wire H is 70 °.
If the safety device is set to operate when it reaches C, the temperature / AC voltage characteristic voltage at which the safety device operates is 75
It becomes 0 mV. If the commercial AC power supply voltage drops to 80 V due to the combined use of other high-capacity devices, the safety device will not operate unless the temperature of the heat-sensitive heating wire H reaches 73 ° C., which may cause a dangerous state.

In view of such problems, it is an object of the present invention to prevent the operating temperature of the safety device from largely changing even when the commercial AC power supply voltage changes.

[0008]

In order to achieve the above-mentioned object, a safety device for a heat-sensitive heating element according to the present invention has a heating line formed of a line that generates heat when a commercial AC power source is energized and a detection line formed of a conductor line. A sheet-shaped heat-sensitive heating element formed by arranging a wire-shaped heat-sensitive heating wire in a zigzag pattern so as to face each other through a heat-sensitive material whose impedance changes according to temperature, and one end of the wire-shaped heat-sensitive heating wire The heating wire and the detection wire are connected via a high-resistance resistor, and the heating wire and the detection wire at the other end of the wire-shaped heat-sensitive heating wire are short-circuited via a low-resistance current fuse, The partial voltage of the temperature / AC voltage characteristic voltage generated between both ends of the detection line by the AC current flowing from the heating line to the detection line through the heat-sensitive material is input to the gate terminal of the first semiconductor switching element, Temperature of heat-sensitive heating element If the temperature becomes abnormally high, the first semiconductor switching element is turned on, and the commercial AC power supply is energized to the heating resistor that is thermally coupled to the thermal fuse provided between the commercial AC power supply and the heating wire. In a safety device for a heat-sensitive heating element composed of an overheat prevention circuit configured to melt off, a partial voltage of the voltage of the commercial AC power supply is input to the gate terminal of the second semiconductor switching element, and the voltage is supplied depending on the voltage of the commercial AC power supply. The second semiconductor switching element is turned on and off to change the ratio of the partial pressure of the temperature / AC voltage characteristic voltage input to the gate terminal of the first semiconductor switching element. .

[0009]

The function of the safety device for the heat-sensitive heating element according to the present invention will be described. Input the voltage division of the commercial AC power supply to the gate terminal of the thyristor which is the second semiconductor switching element,
By turning the second semiconductor switch element on and off according to the voltage of the commercial AC power supply, the temperature input to the gate terminal of the thyristor, which is the first semiconductor switch element,
The ratio of the divided voltage of the AC voltage characteristic voltage is changed.

[0010]

Embodiments of the present invention will be specifically described with reference to the drawings. FIG. 1 is a circuit configuration diagram showing an embodiment of a safety device for a heat-sensitive heating element according to the present invention. The circuit configuration will be described. One end of the heating wire 2 of the heat-sensitive heating wire H is connected to the commercial AC power supply AC via the temperature fuse TF and the on / off switch SW.
, And the other end of the heating wire 2 is connected to the other end of the commercial AC power supply AC via the thermoswitch TS to form a main circuit. Further, a resistor R ₁ having a high resistance value is connected between one end of the detection line 4 of the heat-sensitive heat generation line H and one end of the heat generation line 2, and between the other end of the detection line 4 and the other end of the heat generation line 2. A low resistance current fuse CF is connected to.

Next, resistors R ₂ and R ₃ are connected in series between one end of the detection line 4 and the other end of the heating line 2, and the connection point between the resistors R ₂ and R ₃ and the detection line. Between the other end of 4
A resistor R ₅ and a thyristor SCR ₂ which is a second semiconductor switching element are connected in series. Between both ends of the heating wire 2 resistors R _6, R ₇ are connected in series, the resistors R _6, R
The gate terminal of the thyristor SCR ₂ is connected to the connection point of ₇ . On the other hand, a series circuit of a heating resistor R ₀ and a thyristor SCR ₁ which is a first semiconductor switching element is further connected between both ends of the heating line 2, and the thyristor S
The gate terminal of CR ₁ is connected to the connection point of resistors R ₂ and R ₃ , and the heating resistor R ₀ is a thermal fuse T inserted in the main circuit.
It is designed to be thermally coupled with F.

FIG. 3 is a characteristic diagram showing the relationship between the temperature / AC voltage characteristic voltage generated across the detection line 4 and the commercial AC power supply voltage when the resistance R ₁ = 500 KΩ. According to this figure, when viewed at the same temperature, the commercial AC power supply voltage and the temperature / AC voltage characteristic voltage V _TC are substantially proportional to each other. When the commercial AC power supply voltage is 100 V, the temperature / AC voltage characteristic voltage V _TC is 0.75 V and the thyristor SCR ₁ is conductive in order to operate the safety device when the temperature of the heat-sensitive heating wire H is 70 ° C. When the commercial AC power supply voltage is 90 V, the temperature / AC voltage characteristic voltage V is required to operate the safety device when the temperature of the heat-sensitive heating wire H is 70 ° C.
It is necessary to make thyristor SCR ₁ conductive when _TC is 0.68V.

In FIG. 1, the thyristor SCR₁, SCR
₂The conduction start gate voltage of is 0.6 V, and the resistance constant is
R₂= 72 KΩ, R₃= 120KΩ, R_Five= 390K
Ω, R ₆= 220KΩ, R₇= 1.04 KΩ
Then, the thyristor SCR₂Commercial AC power source that starts conduction
Source voltage V_{AC (START)}Is as follows. V_{AC (START)}= 0.6 (R₆+ R₇) / √2 × R₇≒ 90V ───── Formula commercial AC power supply voltage V_ACIs less than 90V, Thyristor SC
R₂Is in the off state and above 90V is in the on state.
It

When the thyristor SCR ₂ is in the off state (commercial AC power supply voltage V _AC = less than 90 V), the temperature / AC voltage characteristic voltage V _{TC (START1) at which the} thyristor SCR ₁ is in the on state is as follows. V _{TC (START1)} = 0.6 (R ₂ + R ₃ ) / √2 × R ₃ ≈680 mV ──── Expression Therefore, when the commercial AC power supply voltage V _AC with the thyristor SCR ₂ in the off state is less than 90 V. Means that the safety device operates when the temperature / AC voltage characteristic voltage V _TC is 680 mV.

When the thyristor SCR ₂ is on (commercial AC power supply voltage V _AC = 90 V or more) The temperature / AC voltage characteristic voltage V _{TC (START2) at which the} thyristor SCR ₁ is on is given by the following equation. V _{TC (START2)} = 0.6 (R ₂ + R _X ) / √2 × R _X ≈750 mV formula where R _X = (R ₃ × R ₅ ) / (R ₃ + R ₅ ) Therefore, When the commercial AC power supply voltage V _AC with the thyristor SCR ₂ in the ON state is 90 V or more, the safety device operates at the temperature / AC voltage characteristic voltage V _TC of 750 mV.

FIG. 4 is a graph showing the relationship between the commercial AC power supply voltage and the operating temperature of the safety device. The broken line in the drawing shows the characteristics of the conventional circuit shown in FIG. 5, and the solid line shows the book shown in FIG. 7 shows characteristics of the circuit according to the embodiment of the invention. From this graph, the fluctuation of the operating temperature of the safety device when the commercial AC power supply voltage fluctuates in the range of 80 V to 100 V is 3 ° C. in the conventional circuit, whereas the embodiment circuit of the present invention is It turns out that the fluctuation can be suppressed to 1.5 ° C,
Even if the commercial AC power supply voltage changes, the operating temperature of the safety device does not change significantly.

The circuit diagram of the safety device of the present invention is shown in FIG.
It is needless to say that the circuit is not limited to the circuit illustrated in FIG. 1 and that replacement of parts for stabilizing the operation is included in the range not departing from the gist of the present invention, and is not limited to the commercial AC power supply voltage. When a plurality of semiconductor switches that perform switching in accordance with the switching voltages are provided, the fluctuation in operating temperature of the safety device can be further reduced.

[0018]

The safety device for the heat-sensitive heating element according to the present invention is constructed as described above and has the following effects. That is, even if the commercial AC power supply voltage fluctuates significantly, it is possible to suppress the fluctuation of the operating temperature of the safety device to
In particular, even if an abnormality such as a break in the detection wire of the main circuit, a break in the heating wire, local heating, or an overall abnormal temperature rise occurs in the heat-sensitive heating wire, there is no risk of abnormally high temperature and safety is maintained. There are advantages.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram showing an embodiment of a safety device for a heat-sensitive heating element according to the present invention.

FIG. 2 is a configuration diagram of a heat-sensitive heating wire.

FIG. 3 is a characteristic graph showing a relationship between a temperature / AC voltage characteristic voltage generated between both ends of a detection line and a commercial AC power supply voltage.

FIG. 4 is a characteristic graph showing the relationship between the commercial AC power supply voltage and the operating temperature of the safety device.

FIG. 5 is a circuit configuration diagram showing a conventional safety device for a heat-sensitive heating element.

[Explanation of symbols]

H Thermosensitive heating wire SCR ₁ thyristor (first semiconductor switching element) SCR ₂ thyristor (second semiconductor switching element) TF Temperature fuse TS Thermoswitch CF Current fuse R _{1 to} R ₇ Electric resistance

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] August 9, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction content]

The temperature generated between both ends of the detection line
As seen in the characteristic diagram (Fig. 3) showing the relationship between the AC voltage characteristic voltage and the commercial AC power supply voltage, the temperature at the same temperature when the commercial AC power supply voltage fluctuates in the direction of decreasing
Since the AC voltage characteristic voltage also decreases in proportion to the commercial AC power supply voltage, the temperature at which the safety device operates increases as the commercial AC power supply voltage decreases. For example, when the commercial AC power supply voltage is 100 V, the temperature of the heat-sensitive heating wire H is 70 °.
If the safety device is set to operate when it reaches C, the temperature / AC voltage characteristic voltage at which the safety device operates is 75
It becomes 0 mV. If the commercial AC power source voltage is lowered to 80V and the like in combination other high capacity equipment, hazardous condition will be the temperature of the thermal heating wire H does not become 73 ° C safety device does not operate may occur.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction content]

FIG. 4 is a graph showing the relationship between the commercial AC power supply voltage and the operating temperature of the safety device. The broken line in the drawing shows the characteristics of the conventional circuit shown in FIG. 5, and the solid line shows the book shown in FIG. 7 shows characteristics of the circuit according to the embodiment of the invention. From this graph, the fluctuation of the operating temperature of the safety device when the commercial AC power supply voltage fluctuates in the range of 80 V to 100 V is 3 ° C. in the conventional circuit, whereas the embodiment circuit of the present invention is notice that it is possible to obtain reed fluctuations of 1.5 ° C, will not be operating temperature of the safety device even when the commercial AC power supply voltage varies largely varies. Moreover, like this
The operating temperature fluctuated by 3 ° C in the safety device
Case, the maximum temperature when the heat-sensitive heating wire is locally disconnected
Varies from 6 ° C to 9 ° C. The operating temperature of the safety device is 1.
By controlling the temperature to 5 ° C, the maximum temperature is 3 ° C ~
It can be controlled to 4.5 ° C.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction content]

[0018]

The safety device for the heat-sensitive heating element according to the present invention is constructed as described above and has the following effects. That is, it is possible to obtain operation vary the small reed temperature of even a safety device if the commercial AC power supply voltage largely fluctuates, especially disconnection of the main circuit of the detection line, breakage of the heating wire, localized heating and overall Even if an abnormality such as an abnormal temperature rise occurs in the heat-sensitive heating wire, there is an advantage that there is no danger of an abnormally high temperature and safety can be maintained.

Claims (1)

[Claims] 1. A wire shape formed by facing a heating wire made of a line that generates heat when a commercial AC power source is energized and a detection wire made of a conductor line with a heat-sensitive material whose impedance changes according to temperature. A sheet-like heat-sensitive heating element formed by arranging heat-sensitive heating wires in a zigzag shape, a heating wire at one end of the wire-shaped heat-sensitive heating wire, and a detection wire are connected via a high-resistance resistor, and the wire is The heat-generating wire at the other end of the heat-sensitive heating wire and the detection wire are short-circuited via a low-resistance current fuse, and generated between both ends of the detection wire by an alternating current flowing from the heat-generating wire into the detection wire through the heat-sensitive material. By inputting the partial voltage of the temperature / AC voltage characteristic voltage to the gate terminal of the first semiconductor switch element, the first semiconductor switch element is turned on when the temperature of the planar heat-sensitive heating element becomes abnormally high. Let commercial AC power In a safety device for a heat-sensitive heating element, which is composed of an overheat prevention circuit configured to energize a commercial AC power supply to a heating resistor thermally coupled to a temperature fuse provided between The partial voltage of the AC power supply voltage is input to the gate terminal of the second semiconductor switching device, and the second semiconductor switching device is turned on / off according to the voltage of the commercial AC power supply, so that the gate of the first semiconductor switching device is obtained. A safety device for a heat-sensitive heating element, characterized in that a ratio of a partial pressure of the temperature / AC voltage characteristic voltage input to a terminal is changed.