JPH0547452A - Temperature control device - Google Patents

Abstract

PURPOSE:To prevent the occurrence of local overheating by providing two systems of heat sensitive wires near a heating element, comparing temperature values detected with the wires and interrupting power supply to the heating element, when a difference between the values exceeds the prescribed value. CONSTITUTION:Two systems of heat sensitive wires 2 and 3 are laid near a heating element 1, and temperature detecting sections 4 and 5 are connected thereto. Also, a temperature comparison section 6 is provided at a stage next to the sections 4 and 5 for comparing temperature signals outputted therefrom. An output signal P from the comparison section 6, upon exceeding the set value of a temperature difference setting section 7, changes from 1 to 0. When an output signal P from the comparison section 6 is 1, an output signal Q from a temperature control section 10 is sent from an AND element 12 to a thyrister drive section 9. A thyrister 11 is thereby turned on and off to maintain the temperature of the heating element 1 constant. When the output signal P is 0, the signal Q is not sent from the element 12 to the drive section 9. The thyrister 11 is thereby kept off to interrupt power supply to the exothermic body 1. According to this construction, an accident due to local overheating can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature control device such as an electric carpet, an electric blanket and a floor heating device.

[0002]

2. Description of the Related Art In order to control the heat generation temperature of a heating device, it is common to use a thermistor or a heat-sensitive wire as a temperature sensor and control the energization of a heating element based on the temperature signal detected by these temperature sensors. Furthermore, when the detected temperature reaches a predetermined temperature or higher, the control element cuts off the energization.

[0003]

When the temperature sensor is a thermistor, local overheating cannot be detected at a location without the thermistor, and in the case of a heat-sensitive wire, the average temperature of the entire length is detected. Local overheating of unspecified parts cannot be detected early, and in order to prevent accidents due to this local overheating, many thermostats, temperature fuses, etc. are installed in the conventional device, or the number of heat generation units is reduced and many are provided. The method is adopted, and there are problems that the cost is high and there are many failures.

It is an object of the present invention to provide a temperature control device having a simple structure, which detects a local overheat generated at a location where the heating element is not specified at an early stage and cuts off the power supply to the heating element.

[0005]

In order to achieve the above object, in the temperature control device of the present invention, two lines of heat-sensitive wires are used to compare the difference between these detected temperatures, and this difference is the initial set value. When exceeding the limit, the power supply to the heating element is cut off.

As means for cutting off the power supply to the heating element, a thyristor such as a triac as a control element, a relay or a temperature fuse in contact with a heating resistor of a well-known circuit is provided in the current path, and either one or both of them may be provided. Operate at the same time.

The above-mentioned two lines of heat-sensitive wires may have the same or different wire lengths. However, when it is desired to make the wire lengths arbitrary, each temperature detecting unit is disclosed in Japanese Patent Laid-Open No. 3-77036. Using the disclosed technique is convenient because the detection signal is independent of line length.

[0008] It is desirable that the heat-sensitive wires are separately attached to the system depending on the manner of use, where the temperature is likely to be partly high and where it is not.

[0009]

In the temperature control device configured as described above, when a heat insulating material such as a seat is placed on a part of the heating element, the heat radiation in this part is reduced and the temperature rises. The temperature detection unit connected to outputs the "high temperature" signal, while the temperature sensing part connected to this and the temperature detection unit connected to this output the "low temperature" signal, and the temperature comparison unit outputs both detection signals. When a difference of a predetermined value or more is detected, a control element such as a relay or a thyristor is operated to cut off the power supply to the heating element to prevent the temperature of the heating element from rising abnormally.

In the above-mentioned case, if the entire length of one of the heat-sensitive wires is located at a high temperature portion, it is safer because the heating element is de-energized when the abnormal temperature rise at this portion is small.

[0011]

The present invention will be described in detail with reference to the drawings of the embodiments.
In FIG. 1, two lines of heat-sensitive wires 2 are provided close to the heating element 1.
3 is provided. An example of mounting the heat sensitive wires 2 and 3 is shown in FIG.
~ Although shown in FIG. 11, the present invention is not limited to this, and an arbitrary arrangement can be adopted.

Temperature detecting units 4 and 5 are connected to the heat sensitive wires 2 and 3, respectively, and a temperature comparing unit 6 is provided next to the both detecting units 4 and 5. The temperature comparison unit 6 compares the temperature signals output from the detection units 4 and 5.

The difference setting unit 7 attached to the temperature comparison unit 6 determines whether the relay drive unit 8 and / or the thyristor drive unit 9 in the subsequent stage is operated when the difference between the temperature signals of the detection units 4 and 5 is more than a certain value. It is for setting.

The temperature control unit 10 connected to the next stage of the one temperature detection unit 5 is for changing the control temperature of the heating element 1 if necessary, and drives the thyristor according to the output signal of the temperature detection unit 5. The thyristor 11 controls the energization of the heating element 1 by turning on and off the portion 9.

The AND element 12 receives both outputs of the temperature comparison section 6 and the temperature control section 10 as an input, and the output side is connected to the thyristor drive section 9.

FIG. 3 shows the temperature difference d in the temperature comparison unit 6,
FIG. 4 shows the output operation P of the temperature comparison unit 6, and when the difference d between the output signals from both the detection units 4 and 5 in the preceding stage exceeds the set value c in the difference setting unit 7 at the time t1, the output P is output. "1" to "0"
become. As a result, the relay drive unit 8 operates and the contact of the relay 13 is opened.

FIG. 5 shows the temperature signal b of the temperature control unit 10, and FIG. 6 shows the output operation Q of the temperature control unit 10. When the temperature signal b becomes high (b1 in FIG. 5), the output Q starts from "1". When it becomes "0" and b becomes low (b2 in FIG. 5), the output Q becomes "0".
Is changed to "1", and this operation is repeated around an arbitrary set value a.

When the output P of the temperature comparison unit 6 is "1", the output Q of the temperature control unit 10 is transmitted from the AND element 12 to the thyristor drive unit 9 to turn the thyristor 11 on and off, and the heating element 1 outputs. Keep the temperature constant. When the output P of the temperature comparison unit 6 is "0", the output Q is AN as shown in FIG.
The thyristor 11 is not transmitted from the D element 12 to the thyristor drive unit 9, and the thyristor 11 keeps the off state to cut off the power supply to the heating element 1.

The arrangement of the heat-sensitive wires on the electric carpet body (the heating element is omitted, the same applies hereinafter) 14 shown in FIG. 8 is such that the heat-sensitive wires 2 in the central lateral direction are covered with a seat pad 15 and the like, and the heat-sensitive wires 3 on the outside are arranged. On the other hand, it is effective when a temperature difference is likely to occur.

The arrangement of the heat-sensitive wires shown in FIG. 9 is effective when the right heat-sensitive wire 2 is covered with the seat cushion 15 or the like and a temperature difference is likely to occur with respect to the left heat-sensitive wire 3.

In the arrangement of the heat-sensitive wires shown in FIG. 10, the heat-sensitive wire 2 part on the upper left side of the diagonal line is covered with the seat cushion 15 or the like, and a temperature difference is likely to occur with respect to the heat-sensitive wire 3 on the lower right side of the diagonal line, or the chain line X. This is effective when the main body 14 is folded at the -Y position.

In the arrangement of the heat-sensitive wires shown in FIG. 11, the two heat-sensitive wires in the central portion are covered with the seat cushion 15 or the like, and a temperature difference is likely to occur between the heat-sensitive wires 3 on both the left and right sides, or the chain line X-. Y
This is effective when the main body 14 is folded at the position.

FIG. 2 shows another embodiment of the present invention in which the temperature comparing section 6 in FIG. 1 is replaced with a predetermined temperature detecting section 6b and the difference setting section 7 is replaced with a predetermined temperature setting section 7b. ,
As for the operation, referring to the reference numerals of FIGS. 3 and 4, when the temperature d of the predetermined temperature detection unit 6b exceeds the set value c of the predetermined temperature setting unit 7b at the time t1, the output P changes from "1" to "1". It becomes 0 ”. As a result, the relay drive unit 8 operates and the relay 1
Contact 3 is opened.

Similarly to the above, the output P is input to one of the AND elements 12, and when the output P is "0", the thyristor drive unit 9 does not operate and the thyristor remains off.

[0025]

As described above, in the temperature control device of the present invention, the heat-sensitive wires are arranged in two systems. Therefore, when the temperature of a part of the heating element rises and a temperature difference occurs between the two heat-sensitive wires. The power supply to the heating element is cut off, preventing accidents due to local overheating. Furthermore, when the temperature of one of the heat-sensitive wires placed at a location where local overheating is likely to occur rises above a predetermined level, the heating element is de-energized, so unlike a thermostat or temperature fuse, local overheating is prevented over a wide range. There are advantages.

[Brief description of drawings]

FIG. 1 is a block diagram of a main part showing an embodiment of a temperature control device.

FIG. 2 is a block diagram of a main part showing another embodiment of the temperature control device.

FIG. 3 is an explanatory diagram showing a temperature difference detected by a temperature comparison unit.

FIG. 4 is an explanatory diagram showing an output from a temperature comparison unit.

FIG. 5 is an explanatory diagram showing an input temperature signal in a temperature control unit.

FIG. 6 is an explanatory diagram showing an output from a temperature control unit.

FIG. 7 is an explanatory diagram showing an output from an AND element.

FIG. 8 is a plan view showing an example of a heat-sensitive wire arranged on an electric carpet.

FIG. 9 is a plan view showing another embodiment of the heat-sensitive wire arranged on the electric carpet.

FIG. 10 is a plan view showing still another embodiment of the heat-sensitive wire arranged on the electric carpet.

FIG. 11 is a plan view showing still another embodiment of the heat-sensitive wire arranged on the electric carpet.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heating element 2 Heat-sensitive wire 3 Heat-sensitive wire 4 Temperature detection part 5 Temperature detection part 6 Temperature comparison part 6b Predetermined temperature detection part 7 Difference setting part 7b Predetermined temperature setting part 8 Relay drive part 9 Thyristor drive part 10 Temperature control part 11 Thyristor 12 AND element 13 relay

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[Procedure amendment]

[Submission date] December 4, 1991

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction content]

When the output P of the temperature comparison unit 6 is “1”, the output Q of the temperature control unit 10 is transmitted from the AND element 12 to the thyristor drive unit 9 so that the thyristor 11 is turned on / off and the heat generating element 1 outputs. Keep the temperature constant. When the output P of the temperature comparing section 6 is "0", as shown in FIG. 7, the output Q AN
The thyristor 11 is not transmitted from the D element 12 to the thyristor drive unit 9, and the thyristor 11 keeps the OFF state to cut off the power supply to the heating element 1.

Claims (2)

[Claims] 1. Two lines of heat-sensitive wires are provided in the vicinity of the heating element,
A temperature detection unit is connected to each heat-sensitive wire, and a temperature comparison unit that compares the output signals of both detection units is provided at the next stage of both detection units, and the temperature comparison unit outputs the output from both detection units. A temperature control device characterized in that signals are compared, and a control element is operated when the difference is equal to or more than a predetermined value to cut off energization to a heating element. 2. A heat sensitive wire is provided in two systems in the vicinity of the heating element,
When a temperature detector is connected to each heat-sensitive wire, a temperature controller is connected to one temperature detector to control the temperature of the heating element, and the other temperature detector detects a predetermined temperature. A temperature control device characterized in that a control element is operated to cut off power supply to a heating element.