JPS637879Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a thermometer that detects the temperature at a certain temperature measurement site, such as a thermometer, and more specifically to a thermometer that detects the temperature at a certain temperature measurement site, such as a thermistor, whose electrical characteristics change in response to the ambient temperature. The present invention relates to a thermometer using an element.

In conventional thermometers of this type, the temperature sensing element generates a temperature measurement signal in response to the ambient temperature and responds to the temperature measurement signal, regardless of whether or not it is correctly positioned at the temperature measurement site. It is configured to display the temperature. Therefore, even if the temperature measurement display value is obtained when the temperature sensing element is not positioned correctly in the area to be measured, it will be displayed as the temperature of the area to be measured, and the actual temperature of the area to be measured will not be displayed correctly. The problem is that it is not.

In addition, as disclosed in Japanese Patent Application Laid-open No. 57-12331, there are some devices that measure temperature by measuring the temperature measurement time with a timer, but similarly to the above, the temperature measurement device is positioned correctly at the temperature measurement site. Therefore, there is a problem similar to the above regarding the temperature display of the temperature-tested site.

In view of the above, the present invention makes it possible to always accurately detect the temperature at the temperature-tested site by displaying the temperature at the temperature-tested site only when the temperature-sensing element is correctly positioned at the temperature-tested site. The purpose is to

In order to achieve the above object, the present invention includes a main temperature-sensing element, an auxiliary temperature-sensing element disposed at approximately the same location as the main temperature-sensing element, and coated with thermal insulation.
a first temperature difference comparison circuit that sends a temperature measurement start signal when the difference between the respective temperatures detected by the two thermosensing elements exceeds a predetermined value; a second temperature difference comparison circuit that sends out a temperature measurement end signal when the temperature measurement end signal is sent; and a detected temperature display circuit that displays the temperature detected by the main temperature sensing element when the temperature measurement end signal is sent out; In the configuration, temperature measurement is performed when a temperature measurement start signal is sent from the first temperature difference comparison circuit, and after the temperature measurement starts, the difference between the temperatures detected by the main temperature sensing element and the auxiliary temperature sensing element becomes equal to or less than a predetermined value. At this time, a temperature measurement completion signal is sent from the second temperature difference comparison circuit, so that the temperature detected by the main temperature sensing element is displayed on the detected temperature display circuit.

Hereinafter, the present invention will be specifically explained with reference to embodiments shown in the drawings.

FIG. 1 is a block diagram of the main parts of an embodiment of the present invention. The main temperature-sensing element 1 is, for example, a thermistor whose electrical characteristics change in response to ambient temperature. The main temperature sensing element 1 is also connected to a detection temperature circuit section 3, which will be described later, via a main temperature sensing element lead wire 2. The auxiliary temperature sensing element 4 has the same configuration as the main temperature sensing element 1. The auxiliary temperature sensing element 4 is also connected to the detection temperature circuit section 3 via the auxiliary temperature sensing element lead wire 5.
connected to. The auxiliary temperature sensing element 4 is further thermally insulated coated with resin or the like 6. Both of these temperature sensing elements 1 and 4 are housed inside a protective tube 7 such as a glass tube together with their respective lead wires 2 and 5.

Now, the tip of the protective tube 7 of the thermometer having the above-mentioned configuration is positioned with respect to the area to be measured. Then, as shown in FIG. 2, the temperature detected by the main temperature sensing element 1 increases as time passes, as shown by the first curve. In this case, the main temperature sensing element 1
As the element temperature increases to approach the ambient temperature, the internal resistance of the main temperature sensing element 1 decreases, and in response to the decrease in internal resistance, the main temperature measurement from the main temperature sensing element 1 decreases. A signal is input to the detection temperature circuit section 3 via the lead wire 2 . Then, a first curve is drawn corresponding to the main temperature measurement signal.

On the other hand, similarly to the main temperature sensing element 1, the auxiliary temperature sensing element 4 also responds to the ambient temperature by increasing its element temperature and decreasing its internal resistance, and in response, an auxiliary temperature measurement signal is sent to the detection temperature circuit section 3. However, due to the resin 6 coated around the element, the speed at which the element temperature approaches the ambient temperature is slower than that of the main temperature sensing element 1. Therefore, the detected temperature curve based on the auxiliary temperature measurement signal from the auxiliary temperature sensing element 4 gradually increases as time passes, as shown in the second curve.

Therefore, for the first time after applying the tip of the protective tube 7 of the thermometer to the area to be measured, both temperature sensing elements 1,
The difference in detected temperature at 4 becomes large, for example,
At time _t1 , the detected temperature becomes _T1 °C. By the way, this detected temperature difference is obtained when the measured temperature at the temperature-measuring site is T ₀ °C and the tip of the protective tube of the thermometer is correctly positioned at the temperature-measuring site. Therefore, time t ₁
In this case, if temperature measurement is started when the detected temperature difference reaches T ₁ °C, the temperature at the region to be measured can be accurately measured.

Next, start measuring the temperature, and after a predetermined period of time has elapsed,
The difference between the detected temperatures of both the temperature sensing elements 1 and 4 begins to decrease, and at time _t2 , the detected temperature difference becomes _T2 °C. At this time _t2 , the difference in temperature detected by both thermosensors 1 and 4 has become very small, so the temperature detected by main thermosensor 1 is considered to be substantially equal to the temperature at the temperature-tested site. be able to. Therefore, at time _t2 , when the temperature measurement is finished and the temperature is displayed on the detected temperature display section 3 based on the main temperature measurement signal from the main temperature sensing element 1, the temperature at the temperature measured part can be measured correctly. Is displayed.

FIG. 3 is a detailed electrical circuit diagram of the detection temperature circuit section 3. FIG. The main temperature measurement signal from the main temperature sensing element ₁ is input to the first input terminal TT1. The auxiliary temperature measurement signal from the auxiliary temperature sensing element 4 is input to the second input terminal _TT2 . What are the main temperature measurement signal and the auxiliary temperature measurement signal?
First and second input sections of the first temperature difference comparison circuit TC ₁
Input to IN ₁ and IN ₂ respectively. The first temperature difference comparison circuit TC ₁ includes first and second differential amplifiers.
AMP ₁ , AMP ₂ , first and second input sections IN ₁ ,
The main temperature measurement signal and the auxiliary temperature measurement signal input to IN ₂ are differentially amplified, and from the two temperature measurement signals, the detected temperature difference between the temperature sensing elements 1 and 4 is greater than or equal to a predetermined value (for example, T ₁ ℃). It compares and determines whether or not the temperature has warmed up, and when it compares and determines that the detected temperature difference has exceeded a predetermined value, a temperature measurement start signal is sent from the output unit ouT to the temperature measurement start notification circuit TS and the detected temperature difference holding circuit DTL.
Then, send each one. Temperature measurement start notification circuit TS
includes a sounding circuit such as a piezoelectric buzzer, and when a temperature measurement start signal is input, the sounding circuit is driven to soundly notify the start of temperature measurement. On the other hand, the detected temperature difference holding circuit DTL holds the temperature measurement start signal until the temperature measurement operation reset signal is input from the temperature measurement operation reset circuit RS. In this way, it is notified that the thermometer has started measuring the temperature.

On the other hand, the main temperature measurement signal and the auxiliary temperature measurement signal from both the temperature sensing elements 1 and 4 are sent to a second temperature difference comparison circuit.
The signals are input to the first and second input portions IN ₁ ′ and IN ₂ ′ of TC ₂ , respectively. The second temperature difference comparison circuit TC ₂ includes third and fourth differential amplifiers AMP ₃ and AMP ₄ , and receives the main temperature measurement signals inputted to the first and second input sections IN ₁ and IN ₂ ′, respectively. The signal and the auxiliary temperature measurement signal are differentially amplified, and from the two temperature measurement signals, it is determined whether the detected temperature difference in each temperature sensing element 1, 4 has become less than a predetermined value (for example, T ₂ °C) at time t ₂ . Compare and judge
When it is determined by comparison that the detected temperature difference has become less than a predetermined value, a temperature measurement end signal is sent from the output shaft ouT' to the temperature measurement end notification circuit TE.

On the other hand, the temperature measurement start signal held by the temperature difference holding circuit DTL and the temperature measurement end signal from the second temperature difference comparison circuit _TC2 are respectively input to the first and second input portions of the two-input AND circuit AND. The AND circuit AND becomes conductive. Second
The continuity output of the AND circuit AND is held as a display command signal in the display command signal holding circuit DI, and at the same time, the display command signal is sent to the temperature measurement completion notification circuit TE.
Send to.

The temperature measurement end notification circuit TE is the temperature measurement start notification circuit TS.
Similarly, when a temperature measurement end signal is inputted, the conduction output of the AND circuit AND, which includes a sound generation circuit, drives the sound generation circuit to soundly notify the end of temperature measurement. And display command signal holding circuit
The DI holds the display command signal and sends the held display command signal to the detected temperature display circuit DC. The detected temperature display circuit DC, which receives the display command signal, displays the temperature detected by the main temperature sensing element ₁ as a numerical value or the like based on the main temperature measurement signal that is input to the first input terminal TT1.

In this way, in this embodiment, by sounding the start and end of temperature measurement, it is possible to easily understand the temperature measurement status, and only when the temperature measurement device is correctly set at the temperature measurement site Temperature measurement can be started.

As explained above, according to the present invention, since it has the above-mentioned configuration, it is possible to start the temperature measurement operation only when the temperature sensing element is correctly positioned at the temperature measurement site. Effects such as being able to accurately measure and display temperature are exhibited.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of the main parts of an embodiment of the present invention, Fig. 2 is a diagram showing the detection temperature characteristics of the main temperature sensing element and the auxiliary temperature sensing element, and Fig. 3 is the details of the detection temperature circuit section. This is an electrical circuit diagram. 1... Main temperature sensing element, 3... Detection temperature circuit section, 4
...Auxiliary temperature sensing element, 6...Resin, TT ₁ ...First input terminal for inputting the main temperature measurement signal, TT ₂ ...Second input terminal for inputting the auxiliary temperature measurement signal, TC ₁ , TC ₂ ...
...First and second temperature difference comparison circuit, TS...Temperature measurement start notification circuit, DTL...Detected temperature difference holding circuit, TE
...Temperature measurement completion notification circuit, DI...Display command signal holding circuit, DC...Detected temperature display circuit.

Claims (1)

[Scope of utility model registration request] The main temperature sensing element 1 and the auxiliary temperature sensing element 4, which is arranged at almost the same location as the main temperature sensing element 1 and coated with thermal insulation, have a predetermined difference in temperature detected by both the temperature sensing elements 1 and 4. A first temperature difference comparison circuit TC ₁ sends out a temperature measurement start signal when the temperature reaches a predetermined value or more, and a second temperature difference comparison circuit TC 1 sends out a temperature measurement end signal when the difference between the detected temperatures becomes less than or equal to a predetermined value after starting temperature measurement. A temperature measuring device comprising a difference comparison circuit TC ₂ and a detected temperature display circuit DC that displays the temperature detected by the main temperature sensing element 1 when the temperature measurement end signal is sent.