Freezing point constant temperature device and method for thermocouple verification
By designing a freezing constant temperature device including a shell, a heat insulation plate and a container, the problem of unstable temperature control and low measurement accuracy in the prior art freezing thermostat during the thermocouple verification process is solved, and more efficient temperature control and simultaneous verification of multiple sets of thermocouples are achieved.
Patent Information
- Application Number
- CN202411088445.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-09
- Publication Date
- 2025-03-04
AI Technical Summary
During the thermocouple verification process, existing freezing point thermostats have problems such as unstable temperature control, poor constant temperature effect, lack of reading function, and inability to meet the technical standards required by the national verification.
A freezing constant temperature device including a shell, a heat insulation plate and a container is designed. By setting two sets of holes on the top of the shell for placing the thermocouple reference end and a thermometer, a multi-layer heat insulation plate and seal design reduces heat loss and ensures accurate temperature control.
It realizes more stable temperature control, improves measurement accuracy, can verify multiple sets of thermocouples simultaneously, meets national verification requirements, and simplifies operation and maintenance.
Smart Images
Figure CN119555240A_ABST
Abstract
Description
Technical Field
[0001] The present application belongs to the field of freezing point thermostat control, and in particular, relates to a freezing point thermostat device and method for thermocouple calibration. Background Art
[0002] As a key device for temperature measurement using the Seebeck effect, the thermocouple is widely recognized in the JJG75-2022 "Standard Platinum-Rhodium 10-Platinum Thermocouple" verification procedure for its high accuracy and excellent physical and chemical properties. According to Section 6.3.4 of the procedure, the connection between the reference end of the thermocouple and the measuring wire is crucial. The connected thermocouple is usually inserted into the ice point thermostat to the bottom of the glass tube to ensure measurement accuracy.
[0003] However, the "freezing point thermostat" used in the calibration process has extremely high requirements for temperature control, and its freezing point temperature must be maintained within ±0.1°C. At present, the production of this equipment usually relies on filling the shaved ice and ice water mixture after artificial shaved ice into the insulation box, and the thermocouple is randomly inserted into the glass tube of the thermostat. This method has significant defects, such as unstable temperature control, poor constant temperature effect, lack of reading function, and due to the large deviation of zero temperature, it may not meet the technical standards required by the national calibration.
[0004] A similar utility model patent (patent number: CN2O2511915U) proposes a simple thermocouple reference end constant temperature detection device, which aims to solve the shortcomings of the existing technology. When objectively evaluating the existing technology, we found the following shortcomings:
[0005] Traditional freezing point thermostats rely solely on human judgment of the ratio of shaved ice to water and ambient temperature, making it difficult to ensure the accuracy of the reference end temperature being zero degrees.
[0006] Traditional ice point thermostat designs usually only support the calibration of a single thermocouple, but cannot meet the needs of calibrating multiple groups of thermocouples at the same time, reducing experimental efficiency. Summary of the invention
[0007] The purpose of the present application is to overcome the above-mentioned prior art and provide an ice point constant temperature device and method for thermocouple calibration.
[0008] The present application provides an ice point constant temperature device for thermocouple calibration, comprising: a housing, a heat insulation board, and a container;
[0009] The heat insulation board is mounted on the inner cavity wall of the shell to form a heat insulation cavity;
[0010] The container is installed in the heat-insulating cavity and is used to hold the ice-water mixture;
[0011] Two groups of holes are arranged on the top of the housing, each group of holes includes four holes for placing the reference ends of the thermocouples and a special hole for the thermometer in the middle, and the openings of the holes are provided with heat-insulating sealing plugs;
[0012] A thermometer is placed in the special hole for the thermometer;
[0013] A thermocouple reference end is placed in the hole of the thermocouple reference end;
[0014] The measured value of the thermometer is used to provide a reference benchmark for the thermocouple reference end, and the thermocouple reference end provides a temperature measurement reference for the thermocouple measurement end according to the reference benchmark.
[0015] Optionally, it also includes:
[0016] Setting a temperature detection domain, and judging the measurement errors of the two groups of thermocouple measurement ends according to the temperature detection domain, comprises:
[0017] If the first temperature detected by any of the thermocouple measuring ends exceeds the limit value of the temperature detection domain: if the second temperature detected by the other thermocouple measuring end is between the middle value and the limit value in the temperature detection domain, the temperature detected by the thermocouple measuring end in the temperature detection domain is used as the detection temperature; if the second temperature detected by the other thermocouple measuring end is between the middle value and the limit value in the temperature detection domain, the proportion of the ice-water mixture is adjusted;
[0018] If the temperatures detected by the two groups of thermocouple measuring ends are both within the temperature detection range, taking the average of the temperatures detected by the two groups of thermocouple measuring ends as the detection temperature;
[0019] If the temperatures detected by the two groups of thermocouple measuring ends are both beyond the temperature detection range, the data are regarded as invalid data.
[0020] Optionally, the measured value of the thermometer is used to provide a reference benchmark for the reference end of the thermocouple, including:
[0021] A reference value of the reference end of the thermocouple is set according to the measured value.
[0022] Optionally, the measured value of the thermometer includes:
[0023] When the measured value is not within a preset range, the ratio of ice to water in the ice-water mixture is determined and adjusted according to the measured value.
[0024] Optionally, the shell is in a box shape, a barrel shape or an irregular shape.
[0025] Optionally, the heat insulating sealing plug is absorbent cotton.
[0026] Optionally, a thermometer is placed in the thermometer dedicated hole; a thermocouple reference end is placed in the hole of the thermocouple reference end, comprising:
[0027] The thermometer or the thermocouple reference end is placed in a glass tube, and the glass tube is fitted into the dedicated hole of the thermometer or the hole of the thermocouple reference end.
[0028] Optionally, the thermometer includes: a digital thermometer or a platinum resistance thermometer.
[0029] Optionally, each set of holes includes four holes for placing thermocouple reference ends, including:
[0030] The holes are distributed in square rows or circular rows.
[0031] The present application also provides a temperature measurement method, which uses the above-mentioned ice point constant temperature device for thermocouple calibration to provide reference data for the thermocouple measurement end to perform temperature measurement.
[0032] The beneficial effects of this application are:
[0033] The present application provides an ice point thermostat for thermocouple calibration, comprising: a shell, an insulation board, and a container; the insulation board is mounted on the inner wall of the shell to form an insulation cavity; the container is mounted in the insulation cavity to hold an ice-water mixture; two groups of holes are arranged on the top of the shell, each group of holes includes four holes for placing the thermocouple reference end and a special hole for the thermometer in the middle, and the hole openings of the holes are provided with insulation sealing plugs; a thermometer is placed in the special hole for the thermometer; a thermocouple reference end is placed in the hole of the thermocouple reference end; the measurement value of the thermometer is used to provide a reference benchmark for the thermocouple reference end, and the thermocouple reference end provides a temperature measurement reference for the thermocouple measuring end according to the reference benchmark. The present application can judge the proportion of the ice-water mixture based on the measurement of the ice-water mixture by the thermometer, and at the same time, the setting of the dual thermocouple provides calibration for multiple thermocouples, and realizes measurement reference, thereby improving the measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS
[0034] Figure 1 This is a first schematic diagram of an ice point thermostat used for thermocouple calibration in this application;
[0035] Figure 2 The second schematic diagram of the freezing point thermostat used for thermocouple calibration in this application;
[0036] Figure 3 It is a cross-sectional schematic diagram of the ice point constant temperature device used for thermocouple calibration in this application. DETAILED DESCRIPTION
[0037] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that various forms of implementing the present disclosure should not be limited by the embodiments set forth herein. On the contrary, the embodiments are provided to more thoroughly understand the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.
[0038] Please refer to Figure 1 to Figure 3 As shown, the present application provides an ice point constant temperature device for thermocouple calibration, comprising: a housing, a heat insulation board, and a container.
[0039] The shell may be in various shapes, such as a square, a barrel, a sphere or other shapes.
[0040] The inner surface of the shell (the inner surface of the shell) is covered with the insulation layer, including the top insulation board 1, the side insulation board 11 and the bottom insulation board. The insulation board is one of the core structures of the freezing point thermostat, which is composed of multiple layers of insulation material 8 to reduce the influence of the external temperature on the internal ice-water mixture 10 and ensure the constant temperature effect.
[0041] The top of the housing is designed with two groups of holes 2, four in each group, for placing the glass tube 9 of the thermocouple reference end 5. The holes 2 are equipped with sealing plugs to ensure matching with the inner diameter of the glass tube 9 to minimize temperature loss.
[0042] At the center of each group of four holes 2, a hole 3 dedicated to the thermometer is designed for placing the glass tube 7 of the thermometer 6. Such a design enables the thermometer to accurately measure the temperature of the ice-water mixture 10.
[0043] A closed container 4 is installed in the cavity formed by the heat insulation board.
[0044] The shape of the container 4 is determined according to the shape of the cavity formed by the heat insulation board, and is used to contain the ice-water mixture 10 to provide a stable zero-degree environment. There are at least two closed containers 4.
[0045] The reference end 5 of the thermocouple is in contact with the ice-water mixture through the glass tube 9, thereby ensuring that the temperature of the reference end 5 is zero degrees.
[0046] In order to meet the needs of high-precision measurement, this application uses a second-class standard mercury thermometer or a platinum resistance thermometer with a minimum graduation of 0.1°C to ensure accurate temperature reading.
[0047] When a thermal resistor needs to be calibrated, the four reference ends of the thermocouple are connected, and their glass tubes are placed in a group of four holes 2. In the middle hole 3, a glass tube 7 with a mercury thermometer is placed. To ensure sealing, the opening of each glass tube is sealed with absorbent cotton.
[0048] A thermometer placed through the middle hole 3 is used to monitor the temperature in the freezing point thermostat at all times to ensure that it is within the specified zero degree range.
[0049] Furthermore, the measured value of the thermometer is used to provide a reference benchmark for the reference end of the thermocouple, and the reference value of the reference end of the thermocouple is set according to the measured value to achieve more accurate temperature measurement.
[0050] Thermocouple is a temperature measurement device that measures temperature based on the thermoelectric effect. In the embodiment of the present application, it is necessary to ensure the accuracy of the thermocouple measurement, so a constant temperature environment is required as a reference point, usually the reference point is the freezing point (0°C).
[0051] When performing temperature detection, a temperature detection domain for detecting the temperature is set, and the temperature detection domain defines a temperature range, and the measurement value of the thermocouple should fall within this range to ensure its accuracy.
[0052] In the present application, two sets of thermocouple reference ends are provided, and two sets of thermocouple measurement ends corresponding thereto. If the first temperature measured by one of the thermocouples (referred to as "thermocouple A") exceeds the limit of the temperature detection domain, the device will make the following judgment:
[0053] If the second temperature measured by another thermocouple (referred to as "thermocouple B") is within the range from the middle value to the limit value within the temperature detection domain, the measurement value of thermocouple B will be adopted as the final detection temperature.
[0054] If the second temperature measured by thermocouple B is in the range of non-intermediate value to limit value within the temperature detection domain, the proportion of the ice-water mixture needs to be adjusted and the ice-water mixture is determined to be 0±0.1°C based on the thermometer reading.
[0055] If the temperatures measured by the two thermocouples are both within the temperature detection domain, take the average of the two measured values as the final detection temperature to improve accuracy.
[0056] If the temperatures measured by both thermocouples are out of the temperature detection range, the data will be considered invalid and require further inspection or adjustment.
[0057] The present invention reduces heat loss to the greatest extent through multi-layer insulation panels and sealing design, and the thermal insulation effect is greatly improved.
[0058] The device is reasonably designed, easy to use and maintain. Due to the adoption of multiple insulation and sealing measures, the device can accurately grasp the temperature of the reference end of the thermocouple, thereby ensuring the accuracy of the final experimental results.
[0059] The present application also provides a temperature measurement method, which uses the above-mentioned ice point constant temperature device for thermocouple calibration to provide reference data for the thermocouple measurement end to perform temperature measurement.
Claims
1. An ice point thermostat for thermocouple calibration, characterized in that: include: Enclosures, thermal shields and containers; The heat insulation board is mounted on the inner cavity wall of the shell to form a heat insulation cavity; The container is installed in the heat-insulating cavity and is used to hold the ice-water mixture; Two groups of holes are arranged on the top of the housing, each group of holes includes four holes for placing the reference ends of the thermocouples and a special hole for the thermometer in the middle, and the openings of the holes are provided with heat-insulating sealing plugs; A thermometer is placed in the special hole for the thermometer; The thermocouple reference end is placed in the hole for placing the thermocouple reference end; The measured value of the thermometer is used to provide a reference benchmark for the thermocouple reference end, and the thermocouple reference end provides a temperature measurement reference for the thermocouple measurement end according to the reference benchmark.
2. The freezing point constant temperature device for thermocouple calibration according to claim 1, characterized in that: Also includes: Setting a temperature detection domain, and judging the measurement errors of the two groups of thermocouple measurement ends according to the temperature detection domain, comprises: If the first temperature detected by any of the thermocouple measuring ends exceeds the limit value of the temperature detection domain, including: if the second temperature detected by another of the thermocouple measuring ends is between the middle value and the limit value in the temperature detection domain, the temperature detected by the thermocouple measuring end in the temperature detection domain is used as the detection temperature; if the second temperature detected by another of the thermocouple measuring ends is between the middle value and the limit value in the temperature detection domain, the proportion of the ice-water mixture is adjusted; If the temperatures detected by the two groups of thermocouple measuring ends are both within the temperature detection range, taking the average of the temperatures detected by the two groups of thermocouple measuring ends as the detection temperature; If the temperatures detected by the two groups of thermocouple measuring ends are both beyond the temperature detection range, the data are regarded as invalid data.
3. The freezing point constant temperature device for thermocouple calibration according to claim 1, characterized in that: The measured value of the thermometer is used to provide a reference benchmark for the reference end of the thermocouple, including: A reference value of the reference end of the thermocouple is set according to the measured value.
4. The freezing point constant temperature device for thermocouple calibration according to claim 1, characterized in that: The measured values of the thermometer include: When the measured value is not within a preset range, the ratio of ice to water in the ice-water mixture is determined and adjusted according to the measured value.
5. The freezing point constant temperature device for thermocouple calibration according to claim 1, characterized in that: The shape of the shell is box-shaped, barrel-shaped or irregular.
6. The freezing point constant temperature device for thermocouple calibration according to claim 1, characterized in that: The heat-insulating sealing plug is absorbent cotton.
7. The freezing point constant temperature device for thermocouple calibration according to claim 1, characterized in that: A thermometer is placed in the special hole for the thermometer; A thermocouple reference end is placed in the hole of the thermocouple reference end, comprising: The thermometer or the thermocouple reference end is placed in a glass tube, and the glass tube is fitted into the dedicated hole of the thermometer or the hole of the thermocouple reference end.
8. The freezing point constant temperature device for thermocouple calibration according to claim 1, characterized in that: The thermometer includes: a digital thermometer or a platinum resistance thermometer.
9. The freezing point constant temperature device for thermocouple calibration according to claim 1, characterized in that: Each set of holes includes four holes for placing the reference ends of thermocouples, including: The holes are distributed in square rows or circular rows.
10. A temperature measurement method, characterized in that: The ice point constant temperature device for thermocouple calibration as claimed in any one of claims 1 to 9 is used to provide reference data for the thermocouple measuring end to perform temperature measurement.