A weak thermocouple signal disturbance monitoring device

Abstract

The application discloses a weak thermocouple signal disturbance monitoring device, relates to the technical field of temperature monitoring, thermal diffusivity and thermal conductivity measurement, and through the design of a multistage voltage division zero device, the voltage of a direct current power supply is divided into a voltage equal to the background voltage of a thermocouple, and then the background voltage is zeroed, so that the zeroing speed in the measurement process can be obviously improved, and the measurement efficiency is greatly improved. Some high-frequency signal interference in the environment can be shielded through the setting of a capacitor, and the measurement accuracy is improved. The output end of an amplifier is connected to an oscilloscope, weak disturbance signals received by the thermocouple can be recorded with high accuracy through the oscilloscope, and the thermal diffusivity and thermal conductivity of the measured material can be obtained through analysis and processing of the recorded thermal disturbance data.

Description

Technical Field

[0001] This invention relates to the fields of temperature monitoring, thermal diffusivity and thermal conductivity measurement, and more specifically to a device for monitoring weak thermocouple signal disturbances. Background Technology

[0002] Currently, thermocouples can monitor temperature in real time. However, for signals with very small electromotive force fluctuations caused by minute temperature disturbances, direct recording with an oscilloscope is inaccurate and difficult to precisely monitor these weak temperature disturbances. The signal must be amplified by a signal amplifier. However, at high temperatures, the electromotive force generated by the background temperature of the thermocouple is relatively high. The amplified signal often exceeds the amplifier's output range or the oscilloscope's range. Choosing a smaller amplification factor results in insufficient accuracy for observing and measuring weak temperature disturbance signals. Therefore, the electromotive force generated by the thermocouple's background temperature must be zeroed. This ensures that the thermoelectric potential signal generated by weak temperature disturbances can be amplified to a sufficiently high factor without exceeding the amplifier and oscilloscope's range. Transient methods for measuring thermal diffusivity and thermal conductivity require precise measurement of minute electromotive force signal disturbances from thermocouples. Previous signal monitoring schemes were easily affected by background interference, resulting in high noise levels. Furthermore, the zeroing design of thermocouples was crude and inconvenient, and distortion occurred during the zeroing and amplification process.

[0003] Therefore, in view of the above shortcomings, how to design a new device for monitoring weak thermocouple signal disturbances is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0004] In view of this, the present invention provides a weak thermocouple signal disturbance monitoring device to solve the problems existing in the prior art.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A device for monitoring weak thermocouple signal disturbances includes: a thermocouple, a signal zeroing device, a capacitor, and an amplifier; the signal zeroing device includes at least two potentiometers; a first fixed terminal of a first potentiometer is connected to the negative terminal of a power supply, a second fixed terminal is connected to the positive terminal of a power supply, a sliding terminal is connected to the fixed terminal of the second potentiometer, and the other fixed terminal of the second potentiometer is connected to the positive terminal of the power supply; one end of the capacitor is connected to the positive terminal of the power supply, and the other end is connected to the sliding terminal of the second potentiometer; the capacitor, the thermocouple, and the amplifier are connected in series to form a circuit.

[0007] Optionally, the signal zeroing device comprises a first potentiometer, a second potentiometer, and a third potentiometer. The first fixed terminal of the first potentiometer is connected to the first fixed terminal of the second potentiometer, the sliding terminal of the first potentiometer is connected to the second fixed terminal of the second potentiometer, the first fixed terminal of the second potentiometer is connected to the fixed terminal of the third potentiometer, and the sliding terminal of the second potentiometer is connected to the other fixed terminal of the third potentiometer.

[0008] Optionally, it also includes a switch that controls the on / off state of the power supply, wherein the power supply is a regulated DC power supply.

[0009] Optionally, an oscilloscope may also be included, which is connected to the amplifier.

[0010] Optionally, the capacitor is an electrolytic capacitor, with its positive terminal connected to the negative input of the amplifier and its negative terminal connected to the negative terminal of the thermocouple.

[0011] Optionally, the positive input of the oscilloscope is connected to the positive output of the amplifier, and the negative input of the oscilloscope is connected to the negative output of the amplifier.

[0012] As can be seen from the above technical solution, compared with the prior art, the present invention discloses a device for monitoring weak thermocouple signal disturbances. By adopting a multi-stage voltage divider design for the zero-adjustment device, the voltage of the DC power supply is divided into a voltage equal to the background voltage of the thermocouple, and then the background voltage is returned to zero. This significantly improves the zero-adjustment speed during the measurement process, thereby greatly improving the measurement efficiency. By setting a capacitor to shield some high-frequency signal interference in the environment, the measurement accuracy is improved, and the distortion problem in signal amplification is reduced, which greatly improves the measurement accuracy of weak disturbance signals such as thermocouples. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0014] Figure 1 This is a diagram of the zero-adjustment amplifier circuit for the weak thermocouple disturbance signal in Example 1;

[0015] Figure 2 This is a schematic diagram of the weak thermocouple signal disturbance monitoring device in Example 1.

[0016] Among them, 1-power supply; 2-switch; 3-capacitor; 4-amplifier; 5-thermocouple; 6-third precision potentiometer; 7-second precision potentiometer; 8-first precision potentiometer. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Embodiment 1 of this invention discloses a weak thermocouple signal disturbance monitoring device, comprising: a thermocouple 5, a signal zeroing device, a capacitor 3, and an amplifier 4. The signal zeroing device consists of a DC power supply 1, a switch 2, a first precision potentiometer 8, a second precision potentiometer 7, and a third precision potentiometer 6. The weak thermocouple disturbance signal zeroing amplification circuit is as follows: Figure 1 As shown:

[0019] The fixed contact b and moving contact c of the first precision potentiometer 8 are connected in series with the fixed contacts e and d of the second precision potentiometer 7.

[0020] The fixed contact e and moving contact f of the second precision potentiometer 7 are connected in series with the fixed contacts h and g of the third precision potentiometer 6.

[0021] The fixed contact h of the third precision potentiometer 6 is connected to the negative terminal of the amplifier 4, and the moving contact i is connected to the negative terminal of the thermocouple 5.

[0022] After capacitor 3 is connected in parallel with the third precision potentiometer 6, it is connected to the negative input of amplifier 4 and the negative terminal of thermocouple 5. The positive terminal of capacitor 3 is connected to the fixed contact h of the third precision potentiometer 6, and the negative terminal is connected to the moving contact i of the third precision potentiometer 6.

[0023] The positive terminal of thermocouple 5 is connected to the positive terminal of amplifier 4, and the negative terminal is connected to the moving contact i of the third precision potentiometer 6.

[0024] In one specific embodiment, the DC power supply 1 is connected in series with the fixed contacts b and a of the switch 2 and the first precision potentiometer 8. The DC power supply 1 is a dry cell battery and is a regulated DC power supply.

[0025] In one specific embodiment, an oscilloscope is also included. The positive input of the oscilloscope is connected to the positive output of the amplifier 4, and the negative input of the oscilloscope is connected to the negative output of the amplifier 4. The oscilloscope is selected with a sampling frequency greater than 32.5KS / s and a storage depth of not less than 25M.

[0026] In one specific embodiment, capacitor 3 is an electrolytic capacitor with a specification of 220UF / 25V, and the first precision potentiometer 8, the second precision potentiometer 7, and the third precision potentiometer 6 are all 1KΩ resistance potentiometers with variable rotation.

[0027] In one specific embodiment, amplifier 4 is model A11S110, powered by 24V, with DC input of 0–10mV, output of 0–10V, and amplification factor of 60dB.

[0028] like Figure 2 As shown, the working principle of this embodiment 1 is as follows: In order to monitor weak thermocouple signal disturbances accurately, the amplifier amplification factor is 60dB. Under high temperature conditions, the thermocouple signal will exceed the range of the amplifier or oscilloscope if it is directly amplified by the amplifier. Therefore, a zeroing device is needed to bring the voltage signal at the background temperature of the thermocouple to zero.

[0029] The first precision potentiometer 8, the second precision potentiometer 7, the third precision potentiometer 6, and the DC power supply constitute a thermocouple signal zeroing device. The zeroing device adopts a three-stage voltage divider design, which divides the voltage of the DC power supply into a voltage equal to the thermocouple background voltage. Then, the background voltage is returned to zero. First, the amplified thermocouple background signal is adjusted to near zero by adjusting the first precision potentiometer 8, and then the thermocouple background signal is precisely zeroed by adjusting the second precision potentiometer 7 and the third precision potentiometer 6. This can significantly improve the zeroing speed in the measurement process, thereby greatly improving the measurement efficiency.

[0030] The voltage divider zero-adjustment device is connected in series with the negative terminal of the thermocouple, so that the voltage signal from the voltage divider and the thermocouple voltage signal cancel each other out and return to zero.

[0031] The electrolytic capacitor and the voltage divider zero-adjustment device are connected in parallel. The positive terminal of the electrolytic capacitor is connected to the negative input of the amplifier, and the negative terminal of the electrolytic capacitor is connected to the negative terminal of the thermocouple. The electrolytic capacitor can shield some high-frequency signal interference in the environment and improve measurement accuracy.

[0032] An electrolytic capacitor is first connected in parallel with a voltage divider zeroing device, then connected in series with the negative terminal of a thermocouple and finally connected to the input terminal of an amplifier. The positive terminal of the thermocouple is connected to the positive input terminal of the amplifier, and the negative terminal is connected to the negative input terminal. An oscilloscope is connected to the amplifier output terminal. The oscilloscope can record the weak disturbance signals received by the thermocouple with high precision. By analyzing and processing the recorded thermal disturbance data, the thermal diffusivity and thermal conductivity of the measured material can be obtained.

[0033] Embodiment 2 of the present invention discloses another form of a zero-adjustment amplifier circuit for weak thermocouple disturbance signals, comprising: a thermocouple, a signal zero-adjustment device, a capacitor, and an amplifier; the signal zero-adjustment device includes at least two potentiometers; the first fixed terminal of the first potentiometer is connected to the negative terminal of the power supply, the second fixed terminal is connected to the positive terminal of the power supply, the sliding terminal is connected to the fixed terminal of the second potentiometer, the other fixed terminal of the second potentiometer is connected to the positive terminal of the power supply, one end of the capacitor is connected to the positive terminal of the power supply, and the other end is connected to the sliding terminal of the second potentiometer; the capacitor, thermocouple, and amplifier are connected in series to form a circuit.

[0034] In one specific embodiment, a switch is also included to control the on / off state of the power supply, which is a regulated DC power supply.

[0035] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0036] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A device for monitoring weak thermocouple signal disturbances, characterized in that, include: Thermocouple (5), signal zeroing device, capacitor (3), amplifier (4); The signal zeroing device is composed of a first potentiometer (8), a second potentiometer (7), and a third potentiometer (6). The first fixed end of the first potentiometer (8) is connected to the first fixed end of the second potentiometer (7), the sliding end of the first potentiometer (8) is connected to the second fixed end of the second potentiometer (7), the first fixed end of the second potentiometer (7) is connected to the fixed end of the third potentiometer (6), and the sliding end of the second potentiometer (7) is connected to the other fixed end of the third potentiometer (6); The second fixed end of the first potentiometer (8) is connected to the negative terminal of the power supply, and the first fixed end is connected to the positive terminal of the power supply. One end of the capacitor (3) is connected to the positive terminal of the power supply, and the other end is connected to the sliding end of the third potentiometer (6); The capacitor (3), the thermocouple (5), and the amplifier (4) are connected in series to form a circuit; The signal zeroing device adopts a three-stage voltage divider design, which divides the DC power supply voltage into a voltage equal to the thermocouple background voltage. Then, the background voltage is zeroed. First, the amplified thermocouple background signal is adjusted to near zero by adjusting the first potentiometer, and then the thermocouple background signal is zeroed by adjusting the second and third potentiometers to improve the zeroing speed during the measurement process. The signal zeroing device is connected in series with the negative electrode of the thermocouple, and the voltage signal from the voltage divider cancels out the thermocouple voltage signal and returns to zero. The capacitor and the signal zeroing device are connected in parallel. The positive terminal of the capacitor is connected to the negative input of the amplifier, and the negative terminal of the capacitor is connected to the negative terminal of the thermocouple. The capacitor shields the high-frequency signal interference in the environment. The capacitor is first connected in parallel with the signal zeroing device, and then connected in series with the negative terminal of the thermocouple and connected to the input terminal of the amplifier. The positive terminal of the thermocouple is connected to the positive input terminal of the amplifier, and the negative terminal of the thermocouple is connected to the negative input terminal of the amplifier. The output terminal of the amplifier is connected to an oscilloscope. The oscilloscope can record the weak disturbance signal received by the thermocouple with high precision. The thermal diffusivity and thermal conductivity of the measured material are obtained by analyzing and processing the recorded thermal disturbance data.

2. The weak thermocouple signal disturbance monitoring device according to claim 1, characterized in that, It also includes a switch (2), which controls the on / off state of the power supply, which is a regulated DC power supply.

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