Thermocouple plug with cold junction compensation function and preparation method

Abstract

The invention discloses a preparation method of a thermocouple plug with a cold junction compensation function. The preparation method comprises the following steps: preparing a dielectric insulating layer, uniformly coating a metal electrode plate with dielectric paste to form a dielectric paste thin layer, and sintering and curing the coated electrode plate in an oxygen-free environment tubular furnace to form a dielectric insulating thin layer. The method comprises the following steps: preparing a thin-film platinum resistor, coating a medium insulating thin layer with platinum slurry to form a platinum slurry layer, sintering and curing the coated electrode plate in an oxygen-free environment tubular furnace to cure the platinum slurry to form a platinum resistor layer, and symmetrically welding two copper metal wires at the tail end of the platinum resistor layer to form a lead of the thin-film platinum resistor; a thermocouple plug is installed, a metal electrode plate integrated with a thin film platinum resistor is inserted into a positive electrode clamping groove of the thermocouple plug to be fixed, the thin film platinum resistor is connected to an acquisition card, the internal temperature of the plug is accurately measured in real time, measured temperature data is converted into voltage data, and the voltage data and voltage data of the hot end of the thermocouple are superposed. Therefore, thermocouple cold junction compensation is carried out.

Description

Technical Field

[0001] The invention relates to the technical field of testing and control, and in particular to a thermocouple plug with a cold end compensation function and a preparation method thereof. Background Art

[0002] In order to avoid temperature measurement errors caused by changes in the cold-end temperature, traditional solutions usually keep the cold-end temperature constant, usually by using an ice bath or a constant temperature device to stabilize the cold-end temperature. However, this method is very inconvenient in practical applications, especially in scenarios that require portable temperature measurement or dynamic monitoring, and it is difficult to achieve long-term and stable cold-end temperature control. At the same time, due to the frequent fluctuations in the external ambient temperature, it is difficult for the cold-end temperature to remain unchanged, which further leads to the instability and inaccuracy of thermocouple temperature measurement, and cannot meet the needs of high-precision temperature measurement. Summary of the invention

[0003] The present invention proposes a thermocouple plug with a cold end compensation function to solve the problems of achieving long-term and stable cold end temperature control in the traditional way of processing the cold end temperature and the difficulty of keeping the cold end temperature constant as the external environment temperature fluctuates.

[0004] In order to solve the above technical problems, one of the purposes of the present invention is to provide a method for preparing a thermocouple plug with a cold end compensation function, and the specific steps are as follows:

[0005] S1: Prepare a dielectric insulating thin layer, take out the positive metal electrode sheet in the thermocouple plug, apply the dielectric slurry on the screen printing screen, use the metal electrode sheet as the substrate, and use a scraper to evenly apply the dielectric slurry to the surface of the metal electrode sheet to form a dielectric slurry thin layer, put the metal electrode sheet printed with the dielectric slurry thin layer into a tube furnace for sintering, and after sintering, a stable dielectric insulating thin layer is formed on the metal electrode sheet;

[0006] S2: Prepare a thin-film platinum resistor, apply platinum slurry on a silk-screen screen, use the dielectric insulating thin layer on the metal electrode sheet prepared in S1 as a substrate, use a scraper to evenly apply the platinum slurry to the surface of the dielectric insulating thin layer to form a platinum slurry layer, put the metal electrode sheet printed with the platinum slurry layer and the dielectric insulating thin layer into a tube furnace again for sintering, and after sintering, the platinum slurry layer solidifies to form a platinum resistor layer, and use tin solder to weld two copper metal wires to the tail end of the platinum resistor layer as leads of the thin-film platinum resistor;

[0007] S3: Install the thermocouple plug, insert the metal electrode sheet with integrated thin film platinum resistor into the positive card slot of the thermocouple plug, use screws to fix the metal electrode sheet in the card slot, lead the thin film platinum resistor lead out of the plug and connect it to the acquisition card, accurately measure the internal temperature of the plug, and perform cold end compensation.

[0008] Furthermore, the dielectric insulating layer preparation process method comprises the following specific steps:

[0009] S11: Take out the positive metal electrode of the thermocouple plug, immerse it in a beaker containing an alcohol solution, and put the beaker into an ultrasonic cleaning device for ultrasonic cleaning to remove tiny impurities attached to the metal electrode;

[0010] S12: Add a diluent to the dielectric slurry to adjust the viscosity of the slurry so that it has good fluidity so that it can pass through the screen smoothly, apply the dielectric slurry on the printed pattern of the screen printing screen, use the metal electrode sheet as the substrate, and use a scraper to evenly apply the dielectric slurry through the screen to the surface of the metal electrode sheet to form a rectangular dielectric slurry thin layer with a thickness of tens of microns;

[0011] S13: Put the metal electrode sheet printed with the dielectric slurry thin layer into a tube furnace, fill the tube furnace with argon gas to create an oxygen-free environment, set the temperature to 850° C. for 1 hour, and after sintering, the dielectric slurry thin layer solidifies to form a stable dielectric insulating thin layer.

[0012] Furthermore, the method for preparing the thin film platinum resistor comprises the following specific steps:

[0013] S21: applying platinum slurry on a printed pattern of another screen printing plate, taking the dielectric insulating thin layer as a substrate, and using a scraper to evenly apply the platinum slurry through the screen to the surface of the dielectric insulating thin layer to form a platinum slurry layer;

[0014] S22: placing a metal electrode sheet printed with a platinum slurry layer and a dielectric insulating thin layer into a tube furnace, filling the tube furnace with argon gas to create an oxygen-free environment, setting the temperature to 850° C. for 1 hour, and after sintering, the platinum slurry layer solidifies to form a platinum resistor layer;

[0015] S23: Apply two tin solder piles symmetrically at the tail end of the platinum resistor layer, and the two tin solder piles do not touch each other; insert two copper metal wires into the two tin solder piles respectively to contact the tail end of the platinum resistor layer; put the metal electrode sheet into a reflow soldering machine and heat it to melt the two tin solder piles to tightly connect the two copper metal wires to the tail end of the platinum resistor layer, so that the two copper metal wires serve as leads of the thin film platinum resistor.

[0016] Furthermore, the process for installing the thermocouple plug comprises the following specific steps:

[0017] S31: insert the positive metal electrode sheet 4 with integrated thin film platinum resistor into the positive electrode slot 11 of the thermocouple plug, and re-tighten the electrode sheet screw 3 to ensure that the positive metal electrode sheet 4 is firmly fixed in the positive electrode slot 11 of the thermocouple plug, and two copper wires 9 are led out from the square slot 12 of the thermocouple plug, cover the thermocouple plug shell cover 2, and tighten the shell cover screw 1;

[0018] S32: The two leads of the thin film platinum resistor 10 and the two electrodes of the thermocouple are connected to the two acquisition circuits of the acquisition card respectively. The internal temperature data of the plug measured by the thin film platinum resistor 10 and the temperature measurement data of the thermocouple are displayed in the upper computer software. The temperature data of the thin film platinum resistor 10 and the thermocouple are converted into voltage data through a graduation table. The voltage data of the two are superimposed. The superimposed voltage data is converted into temperature data through a graduation table. This temperature data is the temperature data after cold end compensation.

[0019] Furthermore, the S1 medium slurry thin layer has a thickness of tens of microns.

[0020] Furthermore, the sintering conditions of the S1 medium slurry thin layer are as follows: argon is filled into the tubular furnace for 10 minutes, oxygen in the furnace is removed, the initial temperature is set to 30°C, and the temperature is heated to 850°C at a heating rate of 10°C / min, and then the temperature is naturally lowered after being kept at 850°C for 1 hour.

[0021] Furthermore, the S2 platinum slurry layer is formed to have a thickness of 1 mm.

[0022] Furthermore, the sintering conditions of the S2 platinum slurry layer are as follows: argon is filled into the tubular furnace for 10 minutes, oxygen in the furnace is removed, the initial temperature is set to 30°C, and it is heated to 850°C at a rate of 10°C / min, and then naturally cooled after being kept at 850°C for 1 hour.

[0023] Based on the same inventive concept, the present invention also provides a thermocouple plug with a cold end compensation function, which is characterized by comprising a negative metal electrode sheet, a metal electrode sheet 4 integrated with a thin film platinum resistor, a negative electrode slot 5 of the thermocouple plug, a thin film platinum resistor 10, a positive electrode sheet slot 11 of the thermocouple plug, and a square slot 12 of the thermocouple plug.

[0024] The metal electrode sheet 4 integrated with the thin film platinum resistor is inserted into the positive electrode slot 11 of the thermocouple plug, and the negative electrode metal electrode sheet is inserted into the negative electrode slot 5 of the thermocouple plug, and the metal electrode sheet is fixed in the slot with screws;

[0025] The thin film platinum resistor 10 includes a dielectric insulating thin layer 6, a platinum resistor layer 7, a tin solder pile 8, and a copper wire 9. Two copper wires 9 are respectively inserted into the tin solder pile 8 and contact the tail end of the platinum resistor layer 7. The two copper wires serve as leads of the thin film platinum resistor. The leads of the thin film platinum resistor 10 are led out from the square slot 12 of the plug and connected to the acquisition card.

[0026] The present invention embeds a thin-film platinum resistor in a thermocouple plug by screen printing, so that the cold-end temperature can be monitored in real time, thereby realizing cold-end compensation. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 : Metal electrode printed with thin film platinum resistor;

[0028] Figure 2 :Structure diagram of thin film platinum resistor;

[0029] Figure 3 : Internal view of the thermocouple plug;

[0030] Figure 4 : Thermocouple plug diagram;

[0031] Figure 5 : High temperature and high pressure gas test data;

[0032] Among them: 1-shell cover screw, 2-thermocouple plug shell cover, 3-electrode sheet screw, 4-positive metal electrode sheet, 5-negative slot of thermocouple plug, 6-dielectric insulation thin layer, 7-platinum resistor layer, 8-tin solder pile, 9-copper metal wire, 10-thin film platinum resistor, 11-positive slot of thermocouple plug, 12-square slot of thermocouple plug. Specific implementation plan

[0033] The dielectric insulation layer preparation process is used to provide an insulating base so that the metal electrode sheet and the thin film platinum resistor can be firmly bonded together to ensure the stability of electrical insulation; the thin film platinum resistor preparation process is used to integrate the thin film platinum resistor on the metal electrode sheet to form a reliable cold end temperature detection component and provide accurate cold end temperature data; the thermocouple plug installation process is used to fix the metal electrode sheet integrated with the thin film platinum resistor inside the thermocouple plug, measure the internal temperature of the plug through the thin film platinum resistor, and perform thermocouple cold end compensation. The thermocouple plug with a cold end compensation function provided by the present invention can collect cold end temperature data in real time when the thermocouple is working, perform cold end compensation, and thus improve the temperature measurement accuracy of the thermocouple, which has broad application prospects in the field of precision temperature measurement.

[0034] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in combination with the embodiments of the present invention and the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the obtained embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0035] A thermocouple plug with a cold end compensation function comprises a dielectric insulation layer preparation process, a thin film platinum resistor preparation process and a thermocouple plug installation process.

[0036] Preparation process of dielectric insulation layer: take out the positive metal electrode sheet in the thermocouple plug, use ultrasonic cleaning to remove tiny impurities on the surface of the electrode sheet, use screen printing technology to evenly coat the dielectric slurry on the metal electrode sheet to form a dielectric slurry thin layer with a thickness of tens of microns. The coated electrode sheet is placed in a tube furnace and sintered at 850°C for 1 hour in an argon environment to solidify the dielectric slurry and form a stable dielectric insulation thin layer.

[0037] The preparation process of thin-film platinum resistors is to coat platinum slurry on the formed dielectric insulating thin layer through screen printing technology to form a platinum slurry layer with a thickness of 1 mm. The electrode sheet is placed in a tubular furnace again and sintered at 850°C for 1 hour in an argon environment to solidify the platinum slurry to form a platinum resistor layer. Two tin solder piles are symmetrically applied to the tail end of the platinum resistor layer, and two copper wires are inserted. The tin solder piles are heated using a reflow soldering machine to tightly connect the copper wire to the tail end of the platinum resistor layer, thereby forming the leads of the thin-film platinum resistor.

[0038] Thermocouple plug installation process: insert the metal electrode sheet with integrated thin film platinum resistor into the positive card slot of the thermocouple plug and fix it with screws. Connect the thin film platinum resistor to the acquisition card to accurately measure the internal temperature of the plug in real time, and convert the measured temperature data into voltage data, which is superimposed with the voltage data of the hot end of the thermocouple to perform thermocouple cold end compensation.

[0039] Based on the above, through the preparation process provided by the present invention, a thin film platinum resistor can be screen-printed in a thermocouple plug, and the thermocouple plug is used as the cold end of the thermocouple. The thin film platinum resistor can monitor the cold end temperature in real time, and upload the data to the host computer software for cold end compensation, thereby improving the temperature measurement accuracy of the thermocouple. The process of embedding a thin film platinum resistor in a thermocouple plug is simple, low in cost, and has good economy and practicality, so that the cold end compensation technology used in the thermocouple plug has a wide range of application potential in the field of high-precision temperature measurement of thermocouples.

[0040] The present application is further described in detail below in conjunction with the accompanying drawings.

[0041] A thermocouple plug with a cold-end compensation function comprises the following steps:

[0042] Step 1: Use a screwdriver to loosen the two shell cover screws 1 of the thermocouple plug, remove the shell cover 2 of the thermocouple plug, use a screwdriver to loosen the positive electrode sheet screw 3, and pull out the positive metal electrode sheet 4 from the positive slot 11 of the thermocouple plug. Prepare a beaker filled with alcohol solution, immerse the positive metal electrode sheet 4 completely in the alcohol solution, and put the beaker into the ultrasonic cleaning device, set the cleaning temperature to 50°C, and the cleaning time to 10 minutes. After cleaning, the surface of the positive metal electrode sheet 4 is smooth and free of impurities.

[0043] Step 2: Take 10g of dielectric slurry, add appropriate amount of diluent, stir with a cotton swab until the slurry has good fluidity to facilitate smooth passage through the screen, evenly apply the diluted dielectric slurry on the pattern area of ​​the screen printing plate, place the positive metal electrode sheet 4 under the screen printing screen, and use a scraper to evenly print the dielectric slurry on the surface of the positive metal electrode sheet to form a dielectric slurry thin layer with a thickness of tens of microns.

[0044] Step 3: Place the positive electrode sheet 4 printed with a thin layer of dielectric slurry into a tubular furnace, fill the tubular furnace with argon for 10 minutes, remove the oxygen in the furnace, set the initial temperature to 30°C, and heat to 850°C at a heating rate of 10°C / min. Keep at 850°C for 1 hour and then cool naturally. After sintering, the dielectric slurry thin layer solidifies to form a stable dielectric insulating thin layer 6.

[0045] Step 4: Use another screen printing plate to evenly apply the platinum slurry on the screen pattern area, place the dielectric insulating thin layer 6 as a substrate under the screen printing plate, and use a scraper to evenly print the platinum slurry on the dielectric insulating thin layer 6 to form a platinum slurry layer with a thickness of 1 mm.

[0046] Step 5: Place the positive metal electrode sheet 4 printed with the platinum slurry layer and the dielectric insulating thin layer into a tube furnace and repeat the process of filling with argon and exhausting oxygen. Set the initial temperature to 30°C, heat to 850°C at a rate of 10°C / min, keep at 850°C for 1 hour and then cool naturally. After sintering, the platinum slurry layer solidifies to form a platinum resistor layer 7.

[0047] Step 6: Take an appropriate amount of solder paste and smear it symmetrically on both sides of the tail end of the platinum resistor layer 7, and then cover the surface of the solder paste with an appropriate amount of tin solder to form two tin solder piles 8. Take two copper wires 9, insert them into the tin solder piles 8 respectively, and contact the tail end of the platinum resistor layer 7. Put the positive metal electrode sheet 4 into the reflow soldering machine for heating, melt the tin solder pile 8 and tightly connect the two copper wires 9 to the tail end of the platinum resistor layer 7. The copper wires 9 are the leads of the thin film platinum resistor 10.

[0048] Step 7: Insert the positive metal electrode sheet 4 with integrated thin film platinum resistor 10 into the positive electrode slot 11 of the thermocouple plug, and re-tighten the electrode sheet screw 3 to ensure that the positive metal electrode sheet 4 is firmly fixed in the positive electrode slot 11 of the thermocouple plug, and the two copper wires 9 are led out from the square slot 12 of the thermocouple plug, cover the thermocouple plug shell cover 2, and tighten the shell cover screw 1.

[0049] Step 8: Connect the two leads of the thin film platinum resistor 10 and the two electrodes of the thermocouple to the two acquisition circuits of the acquisition card respectively. The internal temperature data of the plug measured by the thin film platinum resistor 10 and the temperature measurement data of the thermocouple are displayed in the upper computer software. The temperature data of the thin film platinum resistor 10 and the thermocouple are converted into voltage data through the graduation table. The voltage data of the two are superimposed, and the superimposed voltage data is converted into temperature data through the graduation table. This temperature data is the temperature data after cold end compensation.

[0050] Obviously, those skilled in the art can make various changes and modifications to the embodiments of the present invention without departing from the spirit and scope of the embodiments of the present invention. Thus, if these modifications and variations of the embodiments of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for preparing a thermocouple plug with a cold end compensation function, characterized in that: The specific steps are as follows: S1: Prepare a dielectric insulating thin layer, take out the positive metal electrode sheet in the thermocouple plug, apply the dielectric slurry on the screen printing screen, use the metal electrode sheet as the substrate, and use a scraper to evenly apply the dielectric slurry to the surface of the metal electrode sheet to form a dielectric slurry thin layer, put the metal electrode sheet printed with the dielectric slurry thin layer into a tube furnace for sintering, and after sintering, a stable dielectric insulating thin layer is formed on the metal electrode sheet; S2: Prepare a thin-film platinum resistor, apply platinum slurry on the screen printing screen, use the dielectric insulating thin layer on the metal electrode sheet prepared in S1 as the substrate, and use a scraper to evenly apply the platinum slurry to the surface of the dielectric insulating thin layer to form a platinum slurry layer. Put the metal electrode sheet printed with the platinum slurry layer and the dielectric insulating thin layer into the tube furnace again for sintering. After sintering, the platinum slurry layer solidifies to form a platinum resistor layer. Use tin solder to weld two copper metal wires to the tail end of the platinum resistor layer as the leads of the thin-film platinum resistor; S3: Install the thermocouple plug, insert the metal electrode sheet with integrated thin film platinum resistor into the positive card slot of the thermocouple plug, use screws to fix the metal electrode sheet in the card slot, lead the thin film platinum resistor lead out of the plug and connect it to the acquisition card, accurately measure the internal temperature of the plug, and perform cold end compensation.

2. The thermocouple plug with cold junction compensation function according to claim 1, characterized in that: The dielectric insulating layer preparation process method comprises the following specific steps: S11: Take out the positive metal electrode of the thermocouple plug, immerse it in a beaker containing an alcohol solution, and put the beaker into an ultrasonic cleaning device for ultrasonic cleaning to remove tiny impurities attached to the metal electrode; S12: Add a diluent to the dielectric slurry to adjust the viscosity of the slurry so that it has good fluidity so that it can pass through the screen smoothly, apply the dielectric slurry on the printed pattern of the screen printing screen, use the metal electrode sheet as the substrate, and use a scraper to evenly apply the dielectric slurry through the screen to the surface of the metal electrode sheet to form a rectangular dielectric slurry thin layer with a thickness of tens of microns; S13: Put the metal electrode sheet printed with the dielectric slurry thin layer into a tube furnace, fill the tube furnace with argon gas to create an oxygen-free environment, set the temperature to 850° C. for 1 hour, and after sintering, the dielectric slurry thin layer solidifies to form a stable dielectric insulating thin layer.

3. The method for preparing a thermocouple plug with cold junction compensation function according to claim 1, characterized in that: The method for preparing the thin film platinum resistor comprises the following specific steps: S21: applying platinum slurry on a printed pattern of another screen printing plate, taking the dielectric insulating thin layer as a substrate, and using a scraper to evenly apply the platinum slurry through the screen to the surface of the dielectric insulating thin layer to form a platinum slurry layer; S22: placing a metal electrode sheet printed with a platinum slurry layer and a dielectric insulating thin layer into a tube furnace, filling the tube furnace with argon gas to create an oxygen-free environment, setting the temperature to 850° C. for 1 hour, and after sintering, the platinum slurry layer solidifies to form a platinum resistor layer; S23: Apply two tin solder piles symmetrically at the tail end of the platinum resistor layer, and the two tin solder piles do not touch each other; insert two copper metal wires into the two tin solder piles respectively to contact the tail end of the platinum resistor layer; put the metal electrode sheet into a reflow soldering machine and heat it to melt the two tin solder piles to tightly connect the two copper metal wires to the tail end of the platinum resistor layer, so that the two copper metal wires serve as leads of the thin film platinum resistor.

4. The method for preparing a thermocouple plug with a cold junction compensation function according to claim 1, characterized in that: The specific steps of the process for installing the thermocouple plug are as follows: S31: Insert the positive metal electrode sheet (4) with integrated thin film platinum resistor into the positive slot (11) of the thermocouple plug, and re-tighten the electrode sheet screw (3) to ensure that the positive metal electrode sheet (4) is firmly fixed in the positive slot (11) of the thermocouple plug, and two copper wires (9) are led out from the square slot (12) of the thermocouple plug. Cover the thermocouple plug shell cover (2) and tighten the shell cover screw (1); S32: The two leads of the thin film platinum resistor (10) and the two electrodes of the thermocouple are respectively connected to the two acquisition circuits of the acquisition card. The internal temperature data of the plug measured by the thin film platinum resistor (10) and the temperature measurement data of the thermocouple are displayed in the upper computer software. The temperature data of the thin film platinum resistor (10) and the thermocouple are converted into voltage data through a graduation table. The voltage data of the two are superimposed. The superimposed voltage data is converted into temperature data through a graduation table. This temperature data is the temperature data after cold end compensation.

5. The method for preparing a thermocouple plug with a cold junction compensation function according to claim 1, characterized in that: The S1 medium slurry thin layer has a thickness of tens of microns.

6. The method for preparing a thermocouple plug with a cold junction compensation function according to claim 1, characterized in that: The sintering conditions of the S1 medium slurry thin layer are as follows: argon is filled into the tubular furnace for 10 minutes, oxygen in the furnace is removed, the initial temperature is set at 30°C, and the temperature is heated to 850°C at a heating rate of 10°C / min, and then the temperature is naturally lowered after being kept at 850°C for 1 hour.

7. The method for preparing a thermocouple plug with a cold junction compensation function according to claim 1, characterized in that: The S2 platinum slurry layer is formed to have a thickness of 1 mm.

8. The method for preparing a thermocouple plug with a cold junction compensation function according to claim 1, characterized in that: The sintering conditions of the S2 platinum slurry layer are as follows: argon is filled into the tubular furnace for 10 minutes, oxygen in the furnace is removed, the initial temperature is set at 30°C, and the temperature is heated to 850°C at a rate of 10°C / min, and then naturally cooled after being kept at 850°C for 1 hour.

9. The thermocouple plug prepared by the method for preparing a thermocouple plug with cold junction compensation function according to any one of claims 1 to 5, characterized in that: It comprises a negative metal electrode sheet, a metal electrode sheet (4) integrated with a thin film platinum resistor, a thermocouple plug negative electrode slot (5), a thin film platinum resistor (10), a thermocouple plug positive electrode sheet slot (11), and a thermocouple plug square slot (12). The metal electrode sheet (4) integrated with the thin film platinum resistor is inserted into the positive electrode slot (11) of the thermocouple plug, and the negative electrode metal electrode sheet is inserted into the negative electrode slot (5) of the thermocouple plug, and the metal electrode sheet is fixed in the slot using screws; The thin film platinum resistor (10) comprises a dielectric insulating thin layer (6), a platinum resistor layer (7), a tin solder pile (8), and a copper metal wire (9). Two copper metal wires (9) are respectively inserted into the tin solder pile (8) and contact the tail end of the platinum resistor layer (7). The two copper metal wires serve as leads of the thin film platinum resistor. The leads of the thin film platinum resistor (10) are led out from the square slot hole (12) of the plug and connected to the acquisition card.

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