JPH06273241A - Temperature detector - Google Patents

Abstract

PURPOSE:To downsize and simplify constitution, and provide a device having quick responsiveness at low cost by supplying electric power balanceable with a resistance value when a resistance thermometer bulb reaches a specified temperature, to a bridge circuit having the resistance thermometer bulb on one side. CONSTITUTION:A bridge circuit 11 is formed of resistors R1, R3 and R4 and a resistance thermometer bulb 2. A resistor having a small temperature coefficient is used as the resistors R1, R3 and R4, and a resistance value of a resistor R2 is selected in the size with which the circuit 11 can balance when a temperature becomes a specified temperature such as, for example, a bodily temperature. Electric power is supplied to the circuit 11 from electric power supply so that a temperature of the resistor R2 becomes constant. Thereby, the resistor R2 is self-heated by an electric current flowing to this, and changes the resistance value. At this time, since the resistor R2 changes the resistance value even when it receives radiation heat of a cold and hot object such as a man and a thing besides a convection of air, the electric power is supplied so that this resistance value becomes a constant value, and that the bridge circuit 11 can be balanced with the resistance value when the resistor R2 reaches a specific temperature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature detecting device for correctly detecting the temperature of a temperature sensing object even under the influence of radiation heat from a cold object.

[0002]

2. Description of the Related Art As a conventional temperature detecting device, for example, as shown in JP-A-63-236935, a nickel or platinum linear temperature measuring resistor is wound around a core,
It is known that this is installed in a thermobox having a hundred-leaf box shape and the temperature is measured from the change in the resistance value of the linear resistance temperature detector.

This is to detect the temperature of the air coming in and out by natural convection from the ventilation holes of the thermobox due to its structure, and the radiant heat from the people, articles, walls, floors and furniture in the room, which is a cold object, is ignored. As a result, there is a gap between the temperature and the temperature that humans actually experience.

On the other hand, a heater and a thermosensitive element are provided on the heat receiving plate, and the heater is heated to heat the heat receiving plate to simulate the human body temperature, thereby partitioning the inside and outside of the small chamber. The one that detects the temperature inside the small chamber and the temperature change of the heat receiving plate that changes according to the heat loss due to external convection and radiation via the heat receiving plate, and knows the sensible temperature correctly,
For example, it is disclosed in Japanese Utility Model Laid-Open No. 62-133137.

[0005]

Since the conventional temperature detecting device capable of detecting the sensible temperature is configured as described above,
In order to detect the sensible temperature, it is necessary to separately prepare a heater, a heat receiving plate and a temperature sensitive element and install them separately in a small room. Therefore, the shape becomes large, and in order to prevent variations in sensitivity, the above heater and heat receiving plate are installed. However, there is a problem that it is necessary to set the relative position of the temperature sensitive element with high accuracy and the setting work is troublesome.

Further, since the small chamber in which the temperature sensitive element and the like are provided has a certain volume, it takes time until the temperature to be measured becomes constant, and the quick response is poor. Since the heater, the heat receiving plate and the temperature sensitive element are used, there are problems that the number of parts is increased and the cost is increased.

The present invention has been made to solve the above-mentioned conventional problems, and by using one resistance temperature detector in place of the heater, the heat receiving plate, and the temperature sensing element, An object of the present invention is to obtain a temperature detecting device which can be downsized and simplified and has a high responsiveness at low cost.

[0008]

A temperature detecting device according to the present invention is provided with a resistance temperature detector which self-heats by passing an electric current, and a bridge circuit having the resistance temperature detector on one side is provided with the resistance temperature detector. The power is supplied so as to balance the resistance value when the body reaches a specified temperature.

[0009]

In the temperature detecting device according to the present invention, the resistance temperature detector is incorporated into one side of the bridge, and the control circuit is arranged to balance the bridge with the resistance value indicated when the resistance temperature detector reaches the specified temperature. By supplying the bridge voltage from the above, the sensible temperature can be obtained from the bridge voltage adjusted to reach the specified temperature.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit diagram showing a specific example of the temperature detecting device. In FIG. 1, R1, R3, and R4 are resistors, R2 is a resistance temperature detector, and these form a bridge circuit 11. Here, the resistance temperature detector R2 is, as shown in FIG. 2A, a flat plate substrate 12, such as a ceramic plate or a resin film,
Alternatively, as shown in FIG. 2B, the wiring pattern 1 of platinum or nickel is formed on the curved base material 12 ′ by printing or vapor deposition.
It consists of 3

The resistors R1, R3, and R4 each have a small temperature coefficient, and when the resistance value of the resistance temperature detector R2 reaches a specified temperature such as body temperature, the bridge circuit 11 operates. Balance (R1 / R2 = R3 / R
4) Select the size.

Further, the resistor R1 of the bridge circuit 11 is
A connection point between the temperature measuring resistor R2 and the resistance R3 and R4 is connected to one input terminal of the operational amplifier 14, and a temperature signal is obtained at the output terminal 15 of the operational amplifier 14. ing. The connection point between the resistors R1 and R3 is connected to the output terminal 15 of the operational amplifier 14, and the connection point between the resistor R4 and the resistance temperature detector R2 is connected to the power supply.

The base material 12 such as the ceramic plate is used.
When measuring the sensible temperature in a wide field of view, is a spherical body or a polyhedron, and the temperature detection region can be expanded.

Next, the operation will be described. First, the temperature detecting device configured as described above is installed in a predetermined temperature measuring region, and the bridge circuit 11 has a power supply which is a bridge voltage control circuit so that the temperature of the resistance temperature detector R2 becomes constant. Powered by. As a result, the resistance temperature detector R2 self-heats due to the current flowing therethrough and changes its resistance value. At this time, the resistance value of the resistance temperature detector R2 changes not only by convection of air but also by radiant heat of a cold object of a person or an object, so that the resistance value becomes constant, that is, Electric power is supplied so that the bridge circuit 11 is balanced with a resistance value when the resistance reaches a specified temperature.

The change in the electric power is caused by the bridge circuit 1.
The change in the perceived temperature can be detected, for example, by obtaining the output of the operational amplifier 14 as the output of 1 and measuring the change in the power. That is, the output of the operational amplifier 14 can be processed by the signal processing circuit to measure the sensible temperature with high accuracy.

In this case, the temperature sensing resistor R2 measures the sensible temperature by selecting the surface shape, color and heat capacity in advance so that the heat radiation by convection and radiation of air is proportional to the sensible temperature. Can be made more precise. And
Since the resistance temperature detector R2 has the functions of the conventional heater, the heat receiving plate, and the temperature sensing element, it is possible to downsize and simplify the overall configuration of the temperature detecting device.

[0017]

As described above, according to the present invention, a resistance temperature detector which self-heats by passing an electric current is provided, and the resistance temperature detector is provided in a bridge circuit having the resistance temperature detector on one side. Since it is configured to supply electric power so that it is balanced by the resistance value when it reaches the specified temperature, it has a simple, compact and inexpensive structure with good responsiveness, responding to the heat effect of a cold object. There is an effect that it is possible to obtain various temperature detections with high accuracy.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a temperature detecting device according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a configuration of a resistance temperature detector in FIG.

[Explanation of symbols]

 11 Bridge circuit R2 RTD

Claims (1)

[Claims] 1. A resistance thermometer that is self-heated by passing an electric current and a resistance thermometer on one side, and balances the resistance value when the resistance thermometer reaches a specified temperature. A temperature detection device having a bridge circuit that is supplied with power.