Thermal resistor for electric heating temperature measurement

Abstract

The embodiment of the utility model discloses a thermal resistor for electric heating temperature measurement. Comprising a constant current source module, a temperature sensing resistor, a temperature sensing resistor temperature measurement module and a temperature output end which are connected in sequence, the temperature sensing resistor temperature measurement module comprises a first resistor, a second resistor and an operational amplifier circuit, and the first end of the first resistor is connected with the first end of the temperature sensing resistor and the constant current source module; the second end of the first resistor is connected with the operational amplifier circuit, the first end of the second resistor is connected with the second end of the temperature sensing resistor and a grounding end, and the second end of the second resistor is connected with the operational amplifier circuit; according to the embodiment of the invention, the constant current source module provides a constant current power supply, the temperature sensing resistor is arranged to carry out electric heating temperature measurement, the measured temperature signal is amplified through the operational amplifier and then is output through the temperature output end, the measurement is simple and reliable, the accuracy and precision of the measurement are improved, and misjudgment and potential safety hazards are avoided.

Description

TECHNICAL FIELD

[0001] The embodiment of the present application relates to the technical field of thermal resistance, in particular to a thermal resistance for electric heating temperature measurement. BACKGROUND

[0002] When the pipeline, container and other equipment run in the winter cold environment, they need to be heated and insulated. The common way is to lay electric heating tape on the surface of the pipeline, container and other equipment and install an insulating layer outside for wrapping. The electric heating tape is composed of a conductive core tape with a "positive temperature coefficient (PTC)" characteristic and an insulating protective layer, which can adjust the output power and the temperature of the heating object with the change of the temperature of the heating object, and can be arbitrarily shortened or lengthened within a certain range, with the advantages of low-voltage operation, easy installation, good flexibility, etc. In order to facilitate the inspection of whether the electric heating tape is working normally, a small section of some parts of the electric heating tape needs to be exposed outside the insulating layer as an inspection section during installation. When the site maintenance personnel check, they touch the exposed electric heating tape with their hands to see if it is hot. If it is hot, it means that it is working normally, and if it is not hot, it means that it is not working normally.

[0003] However, the long-term exposure of the electric heating tape to the environment will cause the surface of the electric heating tape to age faster, especially the surface of the electric heating tape is easy to be scratched by the protective material such as the insulating aluminum skin, which will cause the insulation layer to be damaged and lead to electric leakage, which will cause safety hazards. Touching the temperature with hands is a relatively extensive inspection method, which is easy to misjudge and has low accuracy. CONTENT OF THE UTILITY MODEL

[0004] The embodiment of the present application provides a thermal resistance for electric heating temperature measurement to solve the problems of low accuracy, misjudgment and safety hazards of the existing electric heating temperature measurement method.

[0005] In a first aspect, the embodiment of the present application provides a thermal resistance for electric heating temperature measurement, which comprises a constant current source module, a temperature sensing resistance, a temperature sensing resistance temperature measurement module and a temperature output end connected in sequence. The temperature sensing resistance temperature measurement module comprises a first resistance, a second resistance and an operational amplifier circuit. The first end of the first resistance is connected to the first end of the temperature sensing resistance and the constant current source module. The second end of the first resistance is connected to the operational amplifier circuit. The first end of the second resistance is connected to the second end of the temperature sensing resistance and the ground. The second end of the second resistance is connected to the operational amplifier circuit. The constant current source module is used to provide a constant current power source for the temperature sensing resistance and the temperature sensing resistance temperature measurement module. The first resistance and the second resistance are used to adjust the gain of the temperature signal collected by the temperature sensing resistance. The operational amplifier circuit is used to amplify the temperature signal collected by the temperature sensing resistance and output the signal through the temperature output end.

[0006] In some embodiments, the operational amplifier circuit comprises a first operational amplifier, a second operational amplifier, a third resistor, a fourth resistor, a first capacitor, a negative polarity input end of the first operational amplifier is connected to a second end of the first resistor, a first end of the third resistor and a first end of the first capacitor, a positive polarity input end of the first operational amplifier is connected to a second end of the second resistor, a first end of the fourth resistor and an output end of the second operational amplifier, an output end of the first operational amplifier is connected to a second end of the third resistor, a second end of the first capacitor and the temperature output end, a negative polarity input end of the second operational amplifier is connected to a second end of the fourth resistor, and a positive polarity input end of the second operational amplifier is connected to a ground end.

[0007] In some embodiments, the constant current source module comprises a first amplification chip, a second amplification chip, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor and a third capacitor, a first pin of the first amplification chip is connected to a third pin, a first end of the sixth resistor and a first end of the seventh resistor, a second pin is connected to a first end of the eighth resistor and a first end of the ninth resistor, a first pin of the second amplification chip is connected to a third pin and a second end of the ninth resistor, a second pin is connected to a second end of the seventh resistor and a first end of the temperature sensing resistor, a second end of the eighth resistor is connected to a power supply end and a first end of the third capacitor, a second end of the third capacitor and a second end of the sixth resistor are connected to a ground end.

[0008] In some embodiments, the power supply end is a reference power supply end.

[0009] In some embodiments, the rectification and filtering circuit is further connected to the operational amplifier circuit and the temperature output end.

[0010] In some embodiments, the rectification and filtering circuit comprises a fifth resistor and a second capacitor, a first end of the fifth resistor is connected to the operational amplifier circuit, a second end of the fifth resistor is connected to a first end of the second capacitor and the temperature output end, and a second end of the second capacitor is connected to a ground end.

[0011] In some embodiments, the first operational amplifier is a TL-022C.

[0012] In some embodiments, the second operational amplifier is a TL-060C.

[0013] In some embodiments, the first amplification chip is an LM741.

[0014] In some embodiments, the second amplification chip is an LM358.

[0015] The constant current source module provided by the embodiment of the application provides a constant current power supply, sets a temperature sensing resistor to perform electric heating temperature sensing, amplifies the measured temperature signal through an operational amplifier, and then outputs the temperature signal through a temperature output terminal, so that the measurement is simple and reliable, the accuracy and precision of the measurement are improved, and false judgment and safety hazards are avoided. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 FIG. 1 is a circuit structure schematic diagram of a thermal resistance for electric heating temperature sensing provided by the embodiment of the application. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solutions and advantages of the application clearer, the specific embodiments of the application are further described in detail below with reference to the drawings. It can be understood that the specific embodiments described herein are only used to explain the application, but not to limit the application. In addition, it should be noted that, for the convenience of description, only the parts related to the application are shown in the drawings, but not all the contents. Before discussing the example embodiments in more detail, it should be mentioned that some example embodiments are described as processes or methods depicted as flowcharts. Although the flowcharts describe the operations (or steps) as sequential processes, many of the operations can be implemented in parallel, concurrently or simultaneously. In addition, the order of the operations can be rearranged. The processes can be terminated when the operations are completed, but can also have additional steps not included in the drawings. The processes can correspond to methods, functions, procedures, subroutines, subprograms, etc.

[0018] The thermal resistance for electric heating temperature sensing provided by the embodiment of the application is provided to avoid the problems of low accuracy, easy false judgment and even safety hazards of the existing electric heating temperature sensing method.

[0019] Figure 1 FIG. 1 is a structure schematic diagram of a thermal resistance for electric heating temperature sensing provided by the embodiment of the application. It is shown in FIG. 1 that the thermal resistance for electric heating temperature sensing provided by the embodiment of the application comprises a thermal resistance 1, a constant current source module 2, a temperature output terminal 3 and an operational amplifier 4. Figure 1The electric heating temperature measuring thermistor comprises a constant current source module, a temperature sensing resistor Rntc, a temperature sensing resistor temperature measuring module, a rectifier filter circuit and a temperature output terminal A connected in sequence, the temperature sensing resistor temperature measuring module comprises a first resistor R1, a second resistor R2 and an operational amplifier circuit, a first end of the first resistor R1 is connected with a first end of the temperature sensing resistor Rntc and the constant current source module, a second end of the first resistor R1 is connected with the operational amplifier circuit, a first end of the second resistor R2 is connected with a second end of the temperature sensing resistor Rntc and a ground terminal, a second end of the second resistor R2 is connected with the operational amplifier circuit, the constant current source module is used for providing constant current power supply for the temperature sensing resistor Rntc and the temperature sensing resistor temperature measuring module, the first resistor R1 and the second resistor R2 are used for gain adjustment of a temperature signal collected by the temperature sensing resistor Rntc, and the operational amplifier circuit is used for amplifying the temperature signal collected by the temperature sensing resistor Rntc and then outputting the temperature signal through the temperature output terminal A.

[0020] The operational amplifier circuit comprises a first operational amplifier D1, a second operational amplifier D2, a third resistor R3, a fourth resistor R4 and a first capacitor C1, the constant current source module comprises a first amplification chip U1, a second amplification chip U2, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9 and a third capacitor C3, and the rectifier filter circuit comprises a fifth resistor R5 and a second capacitor C2.

[0021] Specifically, the negative polarity input end of the first operational amplifier D1 is connected with the second end of the first resistor R1, the first end of the third resistor R3 and the first end of the first capacitor C1, the positive polarity input end of the first operational amplifier D1 is connected with the second end of the second resistor R2, the first end of the fourth resistor R4 and the output end of the second operational amplifier D2, the output end of the first operational amplifier D1 is connected with the second end of the third resistor R3, the second end of the first capacitor C1 and the first end of the fifth resistor R5, the negative polarity input end of the second operational amplifier D2 is connected with the second end of the fourth resistor R4, and the positive polarity input end of the second operational amplifier D2 is connected with the ground end; the first pin of the first amplification chip U1 is connected with the third pin, the first end of the sixth resistor R6 and the first end of the seventh resistor R7, the second pin is connected with the first end of the eighth resistor R8 and the first end of the ninth resistor R9, the first pin of the second amplification chip U2 is connected with the third pin and the second end of the ninth resistor R9, the second pin is connected with the second end of the seventh resistor R7 and the first end of the temperature sensing resistor Rntc, the second end of the eighth resistor R8 is connected with the power supply end and the first end of the third capacitor C3, the second end of the third capacitor C3 and the second end of the sixth resistor R6 are connected with the ground end; the second end of the fifth resistor R5 is connected with the first end of the second capacitor C2 and the temperature output end A, and the second end of the second capacitor C2 is connected with the ground end.

[0022] The constant current source module provides a constant current power supply, sets the temperature sensing resistor Rntc to perform electric heating temperature measurement, amplifies the measured temperature signal through the operational amplifier and then outputs through the temperature output end A, and the measurement is simple and reliable, the accuracy and precision of measurement are improved, and false judgment and safety hazards are avoided.

[0023] As a preferred implementation manner, the power supply end is a reference power supply end Vref.

[0024] As a preferred implementation manner, the model of the first operational amplifier D1 is TL-022C.

[0025] As a preferred implementation manner, the model of the second operational amplifier D2 is TL-060C.

[0026] As a preferred implementation manner, the model of the first amplification chip U1 is LM741.

[0027] As a preferred implementation manner, the model of the second amplification chip U2 is LM358.

[0028] The above merely describes the preferred embodiments of the present application and the technical principles applied. The present application is not limited to the specific embodiments described herein, and various obvious changes, modifications and replacements made by those skilled in the art without departing from the scope of the present application shall not be excluded. Therefore, although the present application is described in more detail through the above embodiments, the present application is not limited to the above embodiments, and more other equivalent embodiments can be included without departing from the concept of the present application, and the scope of the present application is determined by the scope of the claims.

Claims

1. A resistance temperature detector (RTD) for electrothermal temperature measurement, characterized in that, The device includes a constant current source module, a temperature sensing resistor, a temperature sensing resistor temperature measurement module, and a temperature output terminal connected in sequence. The temperature sensing resistor temperature measurement module includes a first resistor, a second resistor, and an operational amplifier circuit. The first end of the first resistor is connected to the first end of the temperature sensing resistor and the constant current source module, and the second end of the first resistor is connected to the operational amplifier circuit. The first end of the second resistor is connected to the second end of the temperature sensing resistor and a ground terminal, and the second end of the second resistor is connected to the operational amplifier circuit. The constant current source module provides a constant current power supply to the temperature sensing resistor and the temperature sensing resistor temperature measurement module. The first resistor and the second resistor are used to adjust the gain of the temperature signal collected by the temperature sensing resistor. The operational amplifier circuit amplifies the temperature signal collected by the temperature sensing resistor and outputs it through the temperature output terminal.

2. The resistance temperature detector (RTD) for electrothermal temperature measurement according to claim 1, characterized in that, The operational amplifier circuit includes a first operational amplifier, a second operational amplifier, a third resistor, a fourth resistor, and a first capacitor. The negative input terminal of the first operational amplifier is connected to the second terminal of the first resistor, the first terminal of the third resistor, and the first terminal of the first capacitor. The positive input terminal of the first operational amplifier is connected to the second terminal of the second resistor, the first terminal of the fourth resistor, and the output terminal of the second operational amplifier. The output terminal of the first operational amplifier is connected to the second terminal of the third resistor, the second terminal of the first capacitor, and the temperature output terminal. The negative input terminal of the second operational amplifier is connected to the second terminal of the fourth resistor, and the positive input terminal of the second operational amplifier is connected to ground.

3. The resistance temperature detector (RTD) for electrothermal temperature measurement according to claim 1, characterized in that, The constant current source module includes a first amplifier chip, a second amplifier chip, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, and a third capacitor. The first pin of the first amplifier chip is connected to the third pin, the first end of the sixth resistor, and the first end of the seventh resistor. The second pin of the first amplifier chip is connected to the first end of the eighth resistor and the first end of the ninth resistor. The first pin of the second amplifier chip is connected to the third pin and the second end of the ninth resistor. The second pin of the second amplifier chip is connected to the second end of the seventh resistor and the first end of the temperature sensing resistor. The second end of the eighth resistor is connected to the power supply terminal and the first end of the third capacitor. The second end of the third capacitor and the second end of the sixth resistor are connected to the ground terminal.

4. The resistance temperature detector (RTD) for electrothermal temperature measurement according to claim 3, characterized in that, The power supply terminal is the reference power supply terminal.

5. The resistance temperature detector (RTD) for electrothermal temperature measurement according to claim 1, characterized in that, It also includes a rectifier and filter circuit, which is connected to the operational amplifier circuit and the temperature output terminal.

6. The resistance temperature detector (RTD) for electrothermal temperature measurement according to claim 5, characterized in that, The rectifier and filter circuit includes a fifth resistor and a second capacitor. The first end of the fifth resistor is connected to the operational amplifier circuit, the second end of the fifth resistor is connected to the first end of the second capacitor and the temperature output terminal, and the second end of the second capacitor is connected to the ground terminal.

7. The resistance temperature detector (RTD) for electrothermal temperature measurement according to claim 2, characterized in that, The first operational amplifier is model number TL-022C.

8. The resistance temperature detector (RTD) for electrothermal temperature measurement according to claim 2, characterized in that, The second operational amplifier is model TL-060C.

9. The resistance temperature detector (RTD) for electrothermal temperature measurement according to claim 3, characterized in that, The first amplifier chip is model LM741.

10. The resistance temperature detector (RTD) for electrothermal temperature measurement according to claim 3, characterized in that, The second amplifier chip is model LM358.

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