Efficient thermocouple verification system

Abstract

The utility model discloses a high-efficiency thermocouple verification system. The verification system has a high / low temperature verification furnace double-furnace mode. Silicon carbide soaking pipes for ensuring the temperature uniformity of the furnace chambers are respectively sleeved outside the furnace chambers of the high / low-temperature verification furnace; the high / low temperature verification furnace is controlled by the same temperature control system; the temperature control system comprises a thermocouple for measuring the furnace temperature and a temperature controller; the thermocouple for measuring the furnace temperature is arranged on the high / low temperature verification furnace wall and is connected with the temperature controller; the temperature controller is provided with a switching device for switching temperature control between the high-temperature verification furnace and the low-temperature verification furnace; the temperature controller is directly connected with a computer processing system, and a computer controls the heating body to heat through PID regulation according to a temperature feedback signal. According to the utility model, the verification efficiency is improved, verification of industrial grade platinum rhodium 10-platinum (S type) thermocouples, working platinum rhodium 30-platinum rhodium 6 (B type) thermocouples and nickel chromium-nickel silicon (K type) thermocouples can be realized, and thermocouple verification switching is flexible.

Description

Technical Field

[0001] This utility model belongs to the field of metrology verification and calibration, and specifically relates to a high-efficiency thermocouple verification system. Background Technology

[0002] A thermocouple is a thermoelectric thermometer made of two different noble / inexpensive metal conductors based on the Seebeck effect. It is the most commonly used temperature sensing element in industry. After long-term use, the properties of the thermocouple material will gradually change due to oxidation, corrosion and other reasons, and the thermal characteristics will also change accordingly, resulting in temperature measurement errors. Therefore, thermocouples need to be calibrated regularly to determine whether their errors exceed the specified allowable errors.

[0003] Most thermocouple calibration instruments on the domestic market use small furnaces to ensure uniform temperature distribution within the furnace, calibrating only 1-4 thermocouples per furnace, and calibrating a single type of thermocouple. For calibrating more thermocouples, a multi-furnace calibration system is used, calibrating one thermocouple per furnace, ensuring consistent thermocouple types across the furnaces, and centrally controlling multiple furnaces via computer. This design wastes resources and increases operational complexity. Another newer thermocouple calibration system uses sample loading holes on both sides of the furnace, with the tested thermocouple connector and the standard connector placed symmetrically on both sides of the calibration area. This doubles the number of thermocouples calibrated per furnace, ensuring consistent thermocouple types within each furnace. However, this design suffers from air convection at the front and back of the furnace, making it difficult to guarantee uniform temperature distribution within the furnace.

[0004] Thermoelectric potential acquisition is mainly done by manual switching, and it is necessary to ensure that the parasitic potential and potential difference of each channel are less than 0.4μV. If special circumstances occur during the switching process, the verification results will be inaccurate. The requirements for operators are relatively high, and it is difficult to achieve a fully automatic verification process. Summary of the Invention

[0005] The purpose of this invention is to provide a high-efficiency thermocouple calibration system to solve the problems of limited thermocouple types and quantities in single-furnace calibration and furnace temperature uniformity.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A high-efficiency thermocouple calibration system features a dual-furnace mode with both high and low temperature calibration furnaces. Each furnace cavity is fitted with a silicon carbide heat pipe to ensure temperature uniformity. Both furnaces are controlled by the same temperature control system. This system includes thermocouples for measuring furnace temperature and a temperature controller. The thermocouples are installed on the walls of both furnaces and connected to the temperature controller. The temperature controller has a switching device to switch between the high and low temperature furnaces. The temperature controller is directly connected to a computer processing system, which uses PID control to regulate the heating element based on temperature feedback signals.

[0008] The calibration system is also equipped with a thermostat for providing cold junction compensation for the standard coupler and the coupler under test, and the thermostat temperature is fed back to the computer processing system in real time. The cold junction thermostat is connected to the standard coupler, the coupler under test, and a multi-channel automatic inspection device. The multi-channel automatic inspection device is used to automatically inspect the thermoelectric potential of the standard coupler and the coupler under test, and is connected to the computer processing system.

[0009] The computer processing system and temperature control system are connected and communicate with the temperature control system, multi-channel automatic inspection device, and cold end thermostat to control the automatic operation of the entire calibration system.

[0010] This invention proposes a high-efficiency multi-type thermocouple calibration system. It expands the furnace chamber to ensure uniform temperature distribution, allowing for the calibration of 6-8 thermocouples per furnace, thus improving calibration efficiency. It enables the calibration of industrial-grade platinum-rhodium 10-platinum (Type S) thermocouples, working platinum-rhodium 30-platinum-rhodium 6 (Type B) thermocouples, and nickel-chromium-nickel-silicon (Type K) thermocouples. The system allows for flexible switching between multiple thermocouple types. A multi-channel automatic inspection method replaces the multi-channel transfer switch, eliminating the influence of parasitic potential from the transfer switch on the results and achieving full automation of the calibration process. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the structure of a high-efficiency thermocouple calibration system.

[0012] In the diagram: 1. High-temperature calibration furnace, 2. Low-temperature calibration furnace, 3. Cold end thermostat, 4. Computer processing system, 5. Temperature control system, 6. Multi-channel automatic inspection device. Detailed Implementation

[0013] Example: Figure 1 As shown, a high-efficiency thermocouple calibration system includes a high / low temperature calibration furnace, a cold junction thermostat (ice bottle), a multi-channel automatic inspection device, a temperature control system, and a computer processing system. The high-temperature calibration furnace calibrates industrial-grade platinum-rhodium 10-platinum (Type S) thermocouples and working-grade platinum-rhodium 30-platinum-rhodium 6 (Type B) thermocouples; the low-temperature calibration furnace 2 calibrates nickel-chromium-nickel-silicon (Type K) thermocouples. A layer of silicon carbide heat pipe is added outside the high / low temperature calibration furnace cavity to ensure temperature uniformity within the furnace cavity, and both are controlled by the same temperature control system. The temperature control system includes thermocouples for measuring furnace temperature and a temperature controller. The thermocouples for measuring furnace temperature are installed on the wall of the high / low temperature calibration furnace and connected to the temperature controller. The temperature controller has a switching device to switch temperature control between the high / low temperature calibration furnaces and communicates with the computer processing system. The computer controls the heating element's heating through PID regulation based on the temperature feedback signal.

[0014] The cold junction thermostat (ice bottle) provides constant temperature compensation for the cold junction of the standard coupler and the coupler under test, and feeds back the thermostat temperature to the computer processing system in real time.

[0015] The multi-channel automatic inspection device includes an 8.5-digit high-precision millivoltmeter and a multi-channel scanner, which are used to collect the thermoelectric potential of the standard coupler and the coupler under test. The collected information is uploaded to a computer processing system.

[0016] The computer processing system includes a computer host, industrial control software, and a monitor. It is connected and communicates with the temperature control system, multi-channel automatic inspection device, and cold junction thermostat to control the automatic operation of the entire calibration system.

Claims

1. A high-efficiency thermocouple calibration system, characterized in that: The calibration system features a dual-furnace mode with both high and low temperature calibration furnaces. Each furnace cavity is fitted with a silicon carbide heat pipe to ensure temperature uniformity. Both furnaces are controlled by the same temperature control system, which includes thermocouples for measuring furnace temperature and a temperature controller. The thermocouples are installed on the furnace walls and connected to the temperature controller. The temperature controller has a switching device to switch between the high and low temperature furnaces. The temperature controller is directly connected to a computer processing system, which uses PID control to regulate the heating element based on temperature feedback signals.

2. The high-efficiency thermocouple calibration system as described in claim 1, characterized in that: The calibration system is also equipped with a cold junction compensation thermostat for the standard coupler and the coupler under test, and feeds back the thermostat temperature to the computer processing system in real time. The cold junction compensation thermostat is connected to the standard coupler, the coupler under test, and a multi-channel automatic inspection device. The multi-channel automatic inspection device is used to automatically inspect the thermoelectric potential of the standard coupler and the coupler under test, and is connected to the computer processing system.

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