Laboratory thermostatic bath device and method for thermometer calibration

Abstract

The invention belongs to the technical field of temperature sensor calibration equipment, and particularly relates to a laboratory thermostatic bath device and method for thermometer calibration, and the device comprises a fused salt thermostatic bath, a fused salt heating bath, a fused salt low-temperature bath, and a fused salt recovery bath. The fused salt heating tank is used for conveying liquid-phase fused salt with the temperature of Tmin to the fused salt low-temperature tank and conveying liquid-phase fused salt with the temperature of Tmax to the fused salt constant-temperature tank; the fused salt low-temperature tank is used for conveying liquid-phase fused salt with the temperature of Tmin to the fused salt constant-temperature tank, and the fused salt recovery tank is used for receiving the liquid-phase fused salt conveyed by the fused salt constant-temperature tank; two-way valves are correspondingly arranged in corresponding liquid-phase fused salt conveying pipelines between the fused salt heating tank and the fused salt low-temperature tank, between the fused salt heating tank and the fused salt constant-temperature tank, between the fused salt low-temperature tank and the fused salt constant-temperature tank and between the fused salt constant-temperature tank and the fused salt recovery tank respectively. According to the technical scheme, the test efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of temperature sensor calibration equipment, and in particular relates to a laboratory constant temperature bath device and method for thermometer calibration. Background Art

[0002] For the verification and calibration of temperature measuring devices in the range of 180-550℃, the laboratory generally uses high-purity molten salt as the heat transfer medium. In an environment where the laboratory ambient temperature is 15-35℃ and the humidity does not exceed 85%RH, the solid salt substances in the molten salt constant temperature bath are completely melted by the heater and the temperature control device. Then, the liquid molten salt temperature in the working area is made to reach the set value by the agitator and the temperature control device, and the temperature fluctuation in the working area is maintained at 0.05℃ / 10min and the temperature uniformity is maintained at 0.10℃. The temperature measuring devices in the range of 180-550℃ are calibrated and inspected using high-temperature liquid molten salt as the heat transfer medium, starting from the highest temperature point and in descending order.

[0003] The melting point of high-purity molten salt is 142-148°C and the boiling point is 680°C. Molten salt is a melt composed of metal cations and non-metal anions. It is solid at standard temperature and atmospheric pressure and liquid when the temperature exceeds the melting point. High-temperature molten salt has extraordinary solubility for other substances, so molten salt is often used as a solvent. Most molten salts have good thermal stability within a certain temperature range.

[0004] Part 4 of the National Metrology Technical Specification JJF 1030-2023 Technical Performance Test Specification for Constant Temperature Baths for Temperature Calibration shows the typical structure of constant temperature baths currently used in laboratories, as shown in the attached Figure 1 As shown in , the method for raising the temperature of the heat-conducting medium is to use a heater for heating, and the method for cooling the heat-conducting medium is to use a refrigeration pipe for cooling.

[0005] For the current constant temperature bath in the laboratory using molten salt as the heat transfer medium, the problems include: (1) The heat conduction process itself takes a long time when using a cooling device for cooling and a heating device for heating, which makes the test waiting time long and the test efficiency low. In addition, the stability and volatility of the temperature of the heat transfer medium depend on the heating, cooling and stirring effects, and the adjustment time required to meet the technical performance requirements of the thermostatic bath is long. When the temperature adjustment efficiency and effect are not ideal, the current operation method of the laboratory molten salt thermostatic bath can only choose to heat the high-purity molten salt to 600℃ first, and then gradually cool it down by natural cooling.

[0006] (2) The stirring wings and the stirring shaft directly contact the high-temperature molten salt liquid, which will transfer the high-temperature heat to the stirring motor shaft. The stirring motor is prone to failure due to heat. In particular, the stirring motor of the molten salt heating tank and the molten salt constant temperature tank has the highest failure frequency, resulting in poor operating reliability of the molten salt constant temperature tank system. Summary of the invention

[0007] The technical problem to be solved by the present invention is to make up for the deficiencies of the prior art and provide a laboratory constant temperature bath device and method for thermometer calibration.

[0008] To solve the above technical problems, the technical solution of the present invention is: A laboratory thermostat device for thermometer calibration comprises a molten salt thermostat, wherein a rotating socket disk is provided on the top of the molten salt thermostat, a fixed thermometer A and a plurality of thermometer sockets are provided on the rotating socket disk, the fixed thermometer A is connected to a multi-channel thermometer, a liquid level gauge A, a stirring paddle A and a working area are provided inside the molten salt thermostat, and the multi-channel thermometer and the liquid level gauge A are both connected to a controller; the stirring paddle A is driven by a motor A, and the action of the motor A is controlled by the controller; the working area is located directly below the rotating socket disk, and the temperature measuring part of the fixed thermometer A is located in the working area; the device also comprises a molten salt heating tank, a molten salt low-temperature tank and a molten salt recovery tank; the molten salt heating tank is provided with a molten salt heater, a stirring paddle C and a fixed thermometer C for storing and heating molten salt, and the stirring paddle C is driven by a motor C; the molten salt low-temperature tank is provided with a liquid level gauge B, and the liquid level gauge B is connected to the controller; the molten salt heating tank is used to transport a temperature of T to the molten salt low-temperature tank min The liquid molten salt is delivered to the molten salt constant temperature bath at a temperature of T max Liquid molten salt, 160℃≤T min <T jmin <T jmax <T max ≤600℃,T jmin is the lowest calibration test temperature point of the thermometer to be tested, T jmax It is the highest calibration test temperature point of the thermometer to be tested; the molten salt low temperature tank is used to transport the temperature of T to the molten salt constant temperature tank. min The molten salt recovery tank is used to receive the liquid molten salt transported by the molten salt constant temperature tank; two-way valves are respectively provided in the corresponding liquid molten salt transport pipelines between the molten salt heating tank and the molten salt low-temperature tank, between the molten salt heating tank and the molten salt constant temperature tank, between the molten salt low-temperature tank and the molten salt constant temperature tank, and between the molten salt constant temperature tank and the molten salt recovery tank, and the actions of each two-way valve and the motor C are controlled by the controller; the liquid molten salt is transported by pressure difference or height potential difference.

[0009] Furthermore, it also includes a step bracket, which includes a first layer, a second layer, a third layer and a fourth layer in order from top to bottom in terms of height. The molten salt heating tank is placed on the first layer, the molten salt low-temperature tank is placed on the second layer, the molten salt constant temperature tank is placed on the third layer, and the molten salt recovery tank is placed on the fourth layer. The liquid molten salt is transported through a height potential difference.

[0010] Furthermore, corresponding liquid-phase molten salt transport pipelines between the molten salt heating tank and the molten salt low-temperature tank, between the molten salt heating tank and the molten salt constant temperature tank, between the molten salt low-temperature tank and the molten salt constant temperature tank, and between the molten salt constant temperature tank and the molten salt recovery tank are respectively provided with molten salt valves C, D, B and A. The molten salt valves C, D, B and A are all two-way valves and their actions are all controlled by a controller.

[0011] Furthermore, the molten salt recovery tank transports liquid molten salt to the molten salt heating tank through a molten salt pump and a pipe F, and the operation of the molten salt pump is controlled by a controller.

[0012] Furthermore, a stirring paddle B is provided in the molten salt low-temperature tank. The stirring paddle B includes a stirring shaft B and stirring wings B. The rotation of the stirring shaft B is driven by a motor B. The movement of the motor B is controlled by a controller.

[0013] Furthermore, a partition is provided between the working area and the stirring paddle A.

[0014] Furthermore, the vent holes on the molten salt constant temperature tank, the molten salt heating tank, the molten salt low temperature tank and the molten salt recovery tank are respectively connected to the two-way solenoid valve A, the two-way solenoid valve C, the two-way solenoid valve B and the two-way solenoid valve D, and the actions of the two-way solenoid valve A, the two-way solenoid valve C, the two-way solenoid valve B and the two-way solenoid valve D are all controlled by the controller.

[0015] Furthermore, it also includes a shaft connection unit, which includes a thermal insulation pad and a pair of shaft connections arranged face to face. The shaft connection part includes a cylindrical sleeve and a flange welded to the end of the sleeve. The thermal insulation pad is clamped between the flanges of the two shaft connections arranged face to face, and the flanges of the two shaft connections are fixedly connected by bolts; the output shaft of motor A and stirring paddle A, as well as the output shaft of motor C and stirring paddle C are fixedly connected by the shaft connection unit.

[0016] A method for calibrating a thermometer, using the above-mentioned laboratory thermostat device for calibrating a thermometer, comprises the following steps: S1: Add an appropriate amount of molten salt to the molten salt heating tank, and make the molten salt heater work to heat the molten salt. At the same time, make the stirring paddle C stir the molten salt. When the temperature sent by the fixed thermometer C is T min When the molten salt heater stops working; S2: The temperature of the molten salt is T when it is transported from the molten salt heating tank to the molten salt low temperature tank. minWhen the liquid level sent by the liquid level gauge B reaches the set value, the liquid molten salt is stopped from being transported from the molten salt heating tank to the molten salt low-temperature tank; S3: The molten salt heater is operated to heat the molten salt. When the temperature sent by the fixed thermometer C is T max When the molten salt heater stops working; S4: The temperature of the molten salt is T max When the liquid level sent by the liquid level gauge A reaches the set value h1, the liquid phase molten salt is stopped from being transported from the molten salt heating tank to the molten salt constant temperature tank; S5: Use the stirring paddle A to stir the molten salt; transport the molten salt from the molten salt low temperature tank to the molten salt constant temperature tank at a temperature of T min When the liquid level sent by the liquid level gauge A reaches the set value H, the molten salt low temperature tank stops transporting liquid molten salt to the molten salt constant temperature tank; H = h1 + h2, (HH max ) / H max ≥20%, H max is the height value corresponding to the maximum capacity of the molten salt constant temperature tank (19); Where i is the number of the temperature measurement point from high to low of the thermometer being tested, T i is the temperature value of the i-th measurement point; S6: Compare the temperature value T sent by the current fixed thermometer A s With T i , If T s -T i > 0, the molten salt low temperature tank is intermittently transported to the molten salt constant temperature tank with a temperature of T min Liquid molten salt, to Ts = T i When the liquid phase molten salt is transported from the molten salt low temperature tank to the molten salt constant temperature tank, If T s -T i <0, the molten salt heating tank intermittently transports the temperature of T to the molten salt constant temperature tank. max Liquid molten salt, to Ts = T i When the molten salt heating tank is stopped from conveying the liquid molten salt to the molten salt constant temperature tank; S7: Test the temperature fluctuation and uniformity of the molten salt in the molten salt constant temperature bath according to the specification. When the temperature fluctuation and uniformity meet the requirements, the controller issues a reminder that "the calibration test of the i-th temperature point can be started"; S8: The inspector inserts the thermometer sample to be tested into the thermometer jack and extends it into the working area for calibration inspection; S9: After the inspection is completed, the liquid phase molten salt is transported from the molten salt thermostatic tank to the molten salt recovery tank. When the liquid level sent by the liquid level gauge A reaches the set value h1, the liquid phase molten salt is stopped from being transported from the molten salt thermostatic tank to the molten salt recovery tank. S10: Set i=i+1, perform calibration test at the next temperature point, and repeat steps S5-S9.

[0017] Furthermore, T min =160℃, T max =600℃.

[0018] The beneficial effects that can be achieved by the present invention are: (1) The method of directly cooling and heating the molten salt in the thermostatic bath was abandoned, and the method of liquid phase neutralization of cold and hot molten salt was adopted, which greatly shortened the waiting time for the molten salt thermostatic bath to cool down and meet the requirements of temperature fluctuation and uniformity, and the test efficiency was improved.

[0019] (2) The distance between the agitator shaft and the motor shaft is increased. The agitator shaft and the motor shaft are rigidly connected face to face through two shaft connectors. A high-temperature insulation pad is provided at the face-to-face position of the two shaft connectors to prevent heat from being transferred from the agitator shaft to the motor shaft. At the same time, heat dissipation holes are provided on the outer periphery of the shaft connector. When the agitator shaft and the motor shaft rotate synchronously, the heat on the agitator shaft cannot be effectively transferred to the motor shaft due to the centrifugal force generated by the two rows of rotating heat dissipation holes above it. This heat insulation and air cooling measure ensures that the agitator motor will not fail due to heat and affect the normal operation of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is the typical structure of a thermostatic bath in the technical performance test specification for thermostatic baths used for temperature calibration.

[0021] Figure 2 2 is a top view of an embodiment of the present invention.

[0022] Figure 3 yes Figure 2 AA section view.

[0023] Figure 4 It is a left side view of an embodiment of the present invention.

[0024] Figure 5 It is a main cross-sectional view of the molten salt constant temperature tank in an embodiment of the present invention.

[0025] Figure 6 It is a main cross-sectional view of the molten salt heating tank in an embodiment of the present invention.

[0026] Figure 7 It is a main cross-sectional view of the molten salt low-temperature tank in an embodiment of the present invention.

[0027] Figure 8It is a main cross-sectional view of the molten salt recovery tank in an embodiment of the present invention.

[0028] Fig. 9 2 is a three-dimensional diagram of a shaft connecting member in an embodiment of the present invention.

[0029] Fig.10 It is a main sectional view of the shaft connecting member in an embodiment of the present invention.

[0030] In the figure: 1-ground, 2-step support, 3-tube A, 4-molten salt valve A, 5-tube B, 6-blocking material, 7-stirring shaft A, 8-partition, 9-thermal insulation material, 10-slope bottom surface A, 11-workbench, 12-controller, 13-multi-channel temperature measuring instrument, 14-working area, 15-lower measuring point horizontal plane, 16-middle measuring point horizontal plane, 17-upper measuring point horizontal plane, 18-molten salt liquid level A, 19-molten salt constant temperature tank, 20-cover A, 21- Plug, 22-rotating socket plate, 23-fixed thermometer A, 24-moving thermometer A, 25-liquid level gauge A, 26-two-way solenoid valve A, 27-stirring wing A, 28-bracket A, 29-motor A, 30-tube C, 31-tube D, 32-molten salt valve B, 33-tube E, 34-slope bottom surface B, 35-stirring wing B, 36-molten salt liquid level B, 37-molten salt low temperature tank, 38-fixed thermometer B, 39-cover B, 40-liquid level gauge B, 4 1- stirring shaft B, 42- bracket B, 43- motor B, 44- two-way solenoid valve B, 45- pipe J, 46- molten salt valve C, 47- molten salt heater, 48- stirring wing C, 49- molten salt liquid level C, 50- molten salt heating tank, 51- cover C, 52- fixed thermometer C, 53- liquid level gauge C, 54- stirring shaft C, 55- base plate, 56- pressure ring, 57- sealing ring, 58- key, 59- shaft connector, 591- shaft sleeve, 5911- heat dissipation hole, 5912-keyway, 592-flange; 60-insulation pad, 61-bracket C, 62-horizontal top plate, 63-motor C, 64-shaft C, 65-two-way solenoid valve C, 66-tube F, 67-depressed hole, 68-suction port, 69-slope surface C, 70-molten salt liquid level D, 71-molten salt recovery tank, 72-molten salt pump, 73-liquid level gauge D, 74-two-way solenoid valve D, 75-cover D, 76-molten salt valve D, 77-tube G, 78-tube H; 93-stirring blade, 94-refrigeration tube, 95-heater, 96-temperature controller, 97-thermometer socket, 98-temperature control platinum resistance, 99-stirring motor. DETAILED DESCRIPTION

[0031] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0032] A laboratory thermostat device for thermometer calibration includes a step bracket 2, a molten salt thermostat 19, a molten salt heating tank 50, a molten salt low temperature tank 37, a molten salt recovery tank 71, a workbench 11, a controller 12 and a multi-channel temperature measuring instrument 13, wherein the controller 12 is a display PLC controller, and the exteriors of the molten salt thermostat 19, the molten salt heating tank 50, the molten salt low temperature tank 37 and the molten salt recovery tank 71 are all provided with heat insulation materials 9. The step bracket 2 is used to be placed on the ground 1, the workbench 11 is fixedly connected to the step bracket 2, and the controller 12 and the multi-channel temperature measuring instrument 13 are placed on the workbench 11.

[0033] like Figure 3 As shown, the step support 2 includes the first layer, the second layer, the third layer and the fourth layer in order from top to bottom in terms of height. The molten salt heating tank 50 is placed on the first layer, the molten salt low-temperature tank 37 is placed on the second layer, the molten salt constant temperature tank 19 is placed on the third layer, and the molten salt recovery tank 71 is placed on the fourth layer.

[0034] like Figure 5 As shown, a cover A20, a liquid level gauge A25 and a rotating socket disk 22 are installed on the top of the molten salt thermostatic tank 19, and the liquid level gauge A25 is used to detect the height of the molten salt liquid level A18; a vent A is also provided on the top of the molten salt thermostatic tank 19, and a two-way solenoid valve A26 is installed on the vent A, and the action of the two-way solenoid valve A26 is controlled by the controller 12; a fixed thermometer A23 and 8 thermometer sockets are provided on the rotating socket disk 22, each thermometer socket is equipped with a plug 21 for easy plugging and unplugging, and the thermometer socket is used to plug in a mobile thermometer A24 and a detected thermometer, and the fixed thermometer A23 is connected to the multi-channel thermometer 13, and the multi-channel thermometer 13 and the liquid level gauge A25 are both connected to the controller 12. The interior of the molten salt thermostatic tank 19 is provided with a stirring paddle A and a working area 14, a partition 8 is provided between the working area 14 and the stirring paddle A, the working area 14 is located directly below the rotating socket disk 22, and the temperature measuring part of the fixed thermometer A23 is located in the working area 14. The stirring paddle A includes a stirring shaft A7 and a plurality of stirring wings A27, the stirring shaft A7 is coaxially fixedly connected with the output shaft of the motor A29 through a shaft connection unit, the shaft connection unit is located outside the molten salt thermostatic tank 19, and the motor A29 is fixedly mounted on the bracket A28; the action of the motor A29 is controlled by the controller 12.

[0035] The shaft connection unit includes a heat insulating pad 60 and a pair of shaft connection members 59 disposed face to face. The shaft connection member 59 includes a cylindrical sleeve 591 and a flange 592 welded to the end of the sleeve 591. The heat insulating pad 60 is clamped between the flanges 592 of the two shaft connection members 59 disposed face to face. The flanges 592 of the two shaft connection members 59 are fixedly connected by bolts, and a keyway 5912 is provided on the sleeve 591. The keyway 5912 of the upper shaft connection member 59 in the shaft connection unit is connected to the stirring shaft A7 through a key 58, and the keyway 5912 of the lower shaft connection member 59 is connected to the output shaft of the motor A29 through a key. In order to further improve the heat dissipation effect, there are 4 heat dissipation holes 5911 in a circumferential array on the outer circumference of the sleeve 591.

[0036] The molten salt heating tank 50 is provided with a molten salt heater 47 at the bottom, and a cover C51, a fixed thermometer C52 and a liquid level gauge C53 are installed on the top. The liquid level gauge C53 is used to detect the height of the molten salt liquid level C49. The fixed thermometer C52 and the liquid level gauge C53 are both connected to the controller 12. The top of the molten salt heating tank 50 is also provided with a vent C, and a two-way solenoid valve C65 is installed on the vent C. The action of the two-way solenoid valve C65 is controlled by the controller 12. The molten salt heating tank 50 is also provided with a stirring paddle C. The stirring paddle C is used to stir the molten salt. The stirring paddle C includes a stirring shaft C54 and a plurality of stirring wings C48. The stirring wings C48 pass through the stirring shaft C54. The shaft connection unit is coaxially fixedly connected with the output shaft C64 of the motor C63 (the connection method is the same as the connection method of "the stirring shaft A7 is coaxially fixedly connected with the output shaft of the motor A29 through the shaft connection unit"). The shaft connection unit is located outside the molten salt heating tank 50; the motor C63 is fixedly mounted on the horizontal top plate 62 of the bracket C61, and the base plate 55 of the bracket C61 is fixedly connected with the molten salt heating tank 50. A sealing ring 57 is provided at the rotation connection between the stirring shaft C54 and the molten salt heating tank 50, and the pressure ring 56 and the base plate 55 jointly clamp and fix the sealing ring 57, and the pressure ring 56 and the base plate 55 are fixedly connected by screws. The action of the motor C63 is controlled by the controller 12.

[0037] A cover B39 and a liquid level gauge B40 are installed on the top of the molten salt low-temperature tank 37. The liquid level gauge B40 is used to detect the height of the molten salt liquid level B, and the liquid level gauge B40 is connected to the controller 12; a vent B is also provided on the top of the molten salt low-temperature tank 37, and a two-way solenoid valve B44 is installed on the vent B, and the action of the two-way solenoid valve B44 is controlled by the controller 12; a stirring paddle B is also provided inside the molten salt low-temperature tank 37, and the stirring paddle B is used to stir the molten salt. The stirring paddle B includes a stirring shaft B41 and a stirring wing B35, and the stirring shaft B41 is coaxially fixedly connected to the output shaft of the motor B43 through an axis connection unit (the connection method is the same as the connection method of "the stirring shaft A7 is coaxially fixedly connected to the output shaft of the motor A29 through the axis connection unit"), and the axis connection unit is located outside the molten salt low-temperature tank 37; the motor B43 is fixedly installed on the top of the bracket B42, and the bracket B42 is fixedly connected to the molten salt low-temperature tank 37. A fixed thermometer B38 is also fixed on the top of the molten salt low-temperature tank 37. The fixed thermometer B38 is used to measure the temperature of the molten salt in the molten salt low-temperature tank 37. The fixed thermometer B38 is connected to the controller 12; the action of the motor B43 is controlled by the controller.

[0038] A cover D75 and a liquid level gauge D73 are installed on the top of the molten salt recovery tank 71. The liquid level gauge D73 is used to detect the height of the molten salt liquid level D70, and the liquid level gauge D73 is connected to the controller 12; a vent D is also provided on the top of the molten salt recovery tank 71, and a two-way solenoid valve D74 is installed on the vent D. The action of the two-way solenoid valve D74 is controlled by the controller 12; a slope surface C69 is provided at the bottom of the inner cavity of the molten salt recovery tank 71, and the slope surface C69 extends to the recessed hole 67.

[0039] The suction port 68 of the molten salt pump 72 extends into the recessed hole 67, and the liquid outlet of the molten salt pump 72 is connected to the inner cavity of the molten salt heating tank 50 through the pipe F66; the molten salt heating tank 50 is connected to the inner cavity of the molten salt low-temperature tank 37 through the pipe H78, the molten salt valve C46 and the pipe J45, and the molten salt is transported by the height potential difference; the molten salt heating tank 50 is connected to the inner cavity of the molten salt constant temperature tank 19 through the pipe G77, the molten salt valve D76 and the pipe C30, and the molten salt is transported by the height potential difference; the molten salt low-temperature tank 37 is connected to the inner cavity of the molten salt constant temperature tank 19 through the pipe E33, the molten salt valve B32 and the pipe D31, and the molten salt is transported by the height potential difference; the molten salt constant temperature tank 19 is connected to the inner cavity of the molten salt recovery tank 71 through the pipe B5, the molten salt valve A4 and the pipe A3, and the molten salt is transported by the height potential difference. The molten salt valve C46, ​​the molten salt valve D76, the molten salt valve B32 and the molten salt valve A4 are all two-way valves, and their actions are all controlled by the controller 12. The molten salt heating tank 50 is used to transport the molten salt at a temperature of T to the molten salt low temperature tank 37. min =160℃ liquid molten salt, the temperature is T max =600℃ liquid molten salt (160℃≤T min <T jmin <Tjmax <T max ≤600℃,T jmin is the lowest calibration test temperature point of the thermometer to be tested, T jmax is the highest calibration test temperature point of the thermometer to be tested); the molten salt low temperature tank 37 is used to transport the temperature of T to the molten salt constant temperature tank 19 min =160℃ liquid molten salt, the molten salt recovery tank 71 is used to receive the liquid molten salt transported by the molten salt constant temperature tank 19.

[0040] The bottom of the inner cavity of the molten salt thermostatic tank 19 is provided with a slope bottom surface A10, and the liquid inlet of the tube B5 is arranged at the lowest point of the slope bottom surface A10. The bottom of the inner cavity of the molten salt low temperature tank 37 is provided with a slope bottom surface B34, and the liquid inlet of the tube E33 is arranged at the lowest point of the slope bottom surface B34.

[0041] The connection between each of the above-mentioned pipes and the corresponding grooves is provided with a plugging material 6.

[0042] Liquid level gauge A25, liquid level gauge B40, liquid level gauge C53 and liquid level gauge D73 are all radar liquid level gauges.

[0043] Fixed thermometer A23, mobile thermometer A24, fixed thermometer B38 and fixed thermometer C52 are all quartz-sheathed standard platinum resistance thermometers.

[0044] The two-way joints used in the molten salt valves C46, ​​D76, B32 and A4 and their connections are all set to be tilted downward to avoid molten salt from being retained in the pipelines as much as possible after the test is completed.

[0045] The method for calibrating the thermometer using this embodiment: The steps include: S1: Add an appropriate amount of molten salt to the molten salt heating tank 50, and operate the molten salt heater 47 to heat the molten salt. At the same time, the stirring paddle C stirs the molten salt. When the temperature sent by the fixed thermometer C52 is T min =160°C, the molten salt heater 47 stops working; S2: The molten salt is transported from the molten salt heating tank 50 to the molten salt low temperature tank 37 at a temperature of T min =160℃ liquid molten salt, when the liquid level sent by the liquid level gauge B40 reaches the set value, the liquid molten salt is stopped from being transported from the molten salt heating tank 50 to the molten salt low-temperature tank 37; S3: The molten salt heater 47 is operated to heat the molten salt. When the temperature sent by the fixed thermometer C52 is T max =600°C, the molten salt heater 47 stops working; S4: The molten salt is transported from the molten salt heating tank 50 to the molten salt constant temperature tank 19 at a temperature of T max=600℃ liquid molten salt, when the liquid level sent by the liquid level gauge A25 reaches the set value h1, the liquid molten salt is stopped from being transported from the molten salt heating tank 50 to the molten salt constant temperature tank 19; S5: Use the stirring paddle A to stir the molten salt; transport the molten salt from the molten salt low temperature tank 37 to the molten salt constant temperature tank 19 at a temperature of T min When the liquid level sent by the liquid level gauge A25 reaches the set value H, the molten salt low temperature tank 37 stops transporting the liquid molten salt to the molten salt constant temperature tank 19; H = h1 + h2, (HH max ) / H max ≥20%, H max is the height value corresponding to the maximum capacity of the molten salt thermostatic tank 19; Where i is the number of the temperature measurement point from high to low of the thermometer being tested, T i is the temperature value of the i-th measurement point; S6: Compare the temperature value T sent by the current fixed thermometer A23 s With T i , If T s -T i >0, the molten salt low temperature tank 37 intermittently transports the molten salt with a temperature of T to the molten salt constant temperature tank 19. min Liquid molten salt, to Ts = T i When the liquid phase molten salt is transported from the molten salt low temperature tank 37 to the molten salt constant temperature tank 19, the molten salt is stopped; If T s -T i <0, the molten salt heating tank 50 intermittently transports the molten salt with a temperature of T to the molten salt constant temperature tank 19. max Liquid molten salt, to Ts = T i When the molten salt heating tank 50 stops transporting the liquid molten salt to the molten salt constant temperature tank 19; S7: Test the temperature fluctuation and uniformity of the molten salt in the molten salt constant temperature bath 19 according to the specification. When the temperature fluctuation and uniformity meet the requirements, the controller issues a reminder that "calibration test of the i-th temperature point can be started"; Temperature fluctuation test: read the value once every 10 seconds, record 61 data in total, and the temperature fluctuation is the difference between the maximum temperature value and the minimum temperature value.

[0046] Temperature uniformity test: First, insert the fixed thermometer A23 to 1 / 2 of the depth of the working area 14, and fix its temperature measuring part at the reference position o of the middle measuring point horizontal plane 16. Then insert the mobile thermometer A24 into the working area 14, and fix its temperature measuring part at the position a of the upper measuring point horizontal plane 17. Difference is made between the average value of the fixed thermometer A23 and the average value of the mobile thermometer A24 to obtain the temperature difference Δt of point a relative to point o. a-0 Similarly, the temperature difference Δt between points b, c, and d on the upper measuring point horizontal plane 17 and point o is obtained. b-0 , Δt c-0 , Δt d-0 Then, the temperature difference of points a, b, c, and d on the upper measuring point horizontal plane 17 relative to point o is calculated by averaging the temperature difference Δt of the upper measuring point horizontal plane. u =max(Δt a-0 ,Δt b-0 ,Δt c-0 ,Δt d-0 )- min(Δt a-0 ,Δt b-0 ,Δt c-0 ,Δt d-0 ).

[0047] Similarly, first measure the temperature difference Δt of points e, f, g, and h relative to point o on the horizontal plane 15 of the lower measuring point. e-0 , Δt f-0 , Δt g-0 , Δt h-0 Then, the temperature difference of points e, f, g, and h on the horizontal plane 15 of the lower measuring point relative to point o is calculated by averaging the temperature difference Δt of the horizontal plane of the lower measuring point. l =max(Δt e-0 ,Δt f-0 ,Δt g-0 ,Δt h-0 )- min(Δt e-0 ,Δt f-0 ,Δt g-0 ,Δt h-0 ).

[0048] The horizontal temperature difference is: Δt=max(Δt u ,Δt l ).

[0049] The maximum temperature difference is: δ t = max(Δt a-0 ,Δt b-0 ,Δt c-0 ,Δt d-0 ,Δt e-0 ,Δt f-0 ,Δt g-0,Δt h-0 )-min(Δt a-0 ,Δt b-0 ,Δt c-0 ,Δt d-0 ,Δt e-0 ,Δt f-0 ,Δt g-0 ,Δt h-0 ).

[0050] S8: The inspector inserts the thermometer sample to be tested into the thermometer jack and extends it into the working area 14 to perform calibration inspection; S9: After the inspection is completed, the molten salt thermostatic tank 19 is controlled to transport the liquid molten salt to the molten salt recovery tank 71. When the liquid level sent by the liquid level gauge A25 reaches the set value h1, the molten salt thermostatic tank 19 stops transporting the liquid molten salt to the molten salt recovery tank 71. S10: Set i=i+1, perform calibration test at the next temperature point, and repeat steps S5-S9.

[0051] After the test is completed, the molten salt valve C46 and the molten salt valve D76 are closed, the molten salt valve B32 and the molten salt valve A4 are opened, and the molten salt pump 72 is started to make all the molten salt in the molten salt low-temperature tank 37 flow out to the molten salt constant temperature tank 19, and all the molten salt in the molten salt constant temperature tank 19 flow out to the molten salt recovery tank 71, and all the molten salt in the molten salt recovery tank 71 is pumped to the molten salt heating tank 50.

[0052] The sloped surface C69 at the bottom of the inner cavity of the molten salt recovery tank 71, the sloped bottom surface A10 at the bottom of the inner cavity of the molten salt constant temperature tank 19 and the sloped bottom surface B34 at the bottom of the inner cavity of the molten salt low-temperature tank 37, the existence of the sloped surfaces in these three tanks and the recessed hole 67 at the bottom of the molten salt recovery tank 71 make the liquid phase molten salt recovery more thorough.

[0053] Table 1 Materials list of this example

Claims

1. A laboratory thermostatic bath device for thermometer calibration, comprising a molten salt thermostatic bath (19), wherein a rotating socket disk (22) is provided on the top of the molten salt thermostatic bath (19), a fixed thermometer A (23) and a plurality of thermometer sockets are provided on the rotating socket disk (22), the fixed thermometer A (23) is connected to a multi-channel thermometer (13), a liquid level gauge A (25), a stirring paddle A and a working area (14) are provided inside the molten salt thermostatic bath (19), and the multi-channel thermometer (13) and the liquid level gauge A (25) are both connected to a controller; the stirring paddle A is driven by a motor A (29), and the action of the motor A (29) is controlled by the controller; the working area (14) is located directly below the rotating socket disk (22), and the temperature measuring part of the fixed thermometer A (23) is located in the working area (14); the characteristics are: The invention also includes a molten salt heating tank (50), a molten salt low-temperature tank (37) and a molten salt recovery tank (71); the molten salt heating tank (50) is provided with a molten salt heater (47), a stirring paddle C and a fixed thermometer C (52) for storing and heating the molten salt, and the stirring paddle C is driven by a motor C (63); the molten salt low-temperature tank (37) is provided with a liquid level gauge B (40), and the liquid level gauge B (40) is connected to a controller; the molten salt heating tank (50) is used to transport liquid with a temperature of T to the molten salt low-temperature tank (37). min The liquid molten salt is delivered to the molten salt constant temperature bath (19) at a temperature of T max Liquid molten salt, 160℃≤T min <T jmin <T jmax <T max ≤600℃,T jmin is the lowest calibration test temperature point of the thermometer to be tested, T jmax is the highest calibration test temperature point of the thermometer to be tested; the molten salt low temperature tank (37) is used to transport the temperature of T to the molten salt constant temperature tank (19). min The molten salt recovery tank (71) is used to receive the liquid molten salt transported by the molten salt thermostatic tank (19); two-way valves are respectively provided in the corresponding liquid molten salt transport pipelines between the molten salt heating tank (50) and the molten salt low-temperature tank (37), between the molten salt heating tank (50) and the molten salt thermostatic tank (19), between the molten salt low-temperature tank (37) and the molten salt thermostatic tank (19), and between the molten salt thermostatic tank (19) and the molten salt recovery tank (71); the actions of each two-way valve and the motor C (63) are controlled by a controller; the liquid molten salt is transported by pressure difference or height potential difference.

2. The laboratory thermostat device for thermometer calibration according to claim 1, characterized in that: It also includes a step support (2), which includes a first layer, a second layer, a third layer and a fourth layer in order from top to bottom in terms of height, a molten salt heating tank (50) is placed on the first layer, a molten salt low-temperature tank (37) is placed on the second layer, a molten salt constant temperature tank (19) is placed on the third layer, and a molten salt recovery tank (71) is placed on the fourth layer, and the liquid phase molten salt is transported by using a height potential difference.

3. The laboratory thermostat device for thermometer calibration according to claim 1, characterized in that: A molten salt valve C (46), a molten salt valve D (76), a molten salt valve B (32) and a molten salt valve A (4) are respectively provided in the corresponding liquid phase molten salt transport pipelines between the molten salt heating tank (50) and the molten salt low temperature tank (37), between the molten salt heating tank (50) and the molten salt constant temperature tank (19), between the molten salt low temperature tank (37) and the molten salt constant temperature tank (19), and between the molten salt constant temperature tank (19) and the molten salt recovery tank (71). The molten salt valve C (46), the molten salt valve D (76), the molten salt valve B (32) and the molten salt valve A (4) are all two-way valves and their actions are all controlled by a controller.

4. The laboratory thermostat device for thermometer calibration according to claim 1, characterized in that: The molten salt recovery tank (71) transports liquid-phase molten salt to the molten salt heating tank (50) via a molten salt pump (72) and a pipe F (66), and the operation of the molten salt pump (72) is controlled by a controller.

5. The laboratory thermostat device for thermometer calibration according to claim 1, characterized in that: The molten salt low-temperature tank (37) is provided with a stirring paddle B, which comprises a stirring shaft B (41) and stirring wings B (35). The rotation of the stirring shaft B (41) is driven by a motor B (43), and the movement of the motor B (43) is controlled by a controller.

6. The laboratory thermostat device for thermometer calibration according to claim 1, characterized in that: A partition (8) is provided between the working area (14) and the stirring paddle A.

7. The laboratory thermostat device for thermometer calibration according to claim 1, characterized in that: The vent holes on the molten salt constant temperature tank (19), the molten salt heating tank (50), the molten salt low temperature tank (37) and the molten salt recovery tank (71) are respectively connected to a two-way solenoid valve A (26), a two-way solenoid valve C (65), a two-way solenoid valve B (44) and a two-way solenoid valve D (74), and the actions of the two-way solenoid valve A (26), the two-way solenoid valve C (65), the two-way solenoid valve B (44) and the two-way solenoid valve D (74) are all controlled by a controller.

8. The laboratory thermostat device for thermometer calibration according to claim 1, characterized in that: The invention also comprises a shaft connection unit, the shaft connection unit comprising a heat insulating pad (60) and a pair of shaft connection members (59) arranged face to face, the shaft connection member (59) comprising a cylindrical shaft sleeve (591) and a flange (592) welded to the end of the shaft sleeve (591), the heat insulating pad (60) being clamped between the flanges (592) of the two shaft connection members (59) arranged face to face, the flanges (592) of the two shaft connection members (59) being fixedly connected by bolts; the output shaft of the motor A (29) and the stirring paddle A, and the output shaft of the motor C (63) and the stirring paddle C are fixedly connected by the shaft connection unit.

9. A method for calibrating a thermometer, characterized in that: The method of using the thermostat device for calibrating a thermometer according to any one of claims 1 to 8 comprises the following steps: S1: Add an appropriate amount of molten salt to the molten salt heating tank (50), and operate the molten salt heater (47) to heat the molten salt. At the same time, the stirring paddle C stirs the molten salt. When the temperature sent by the fixed thermometer C (52) is T min When the molten salt heater (47) stops working; S2: The molten salt heating tank (50) is used to transport the molten salt to the molten salt low temperature tank (37) at a temperature of T min When the liquid level sent by the liquid level gauge B (40) reaches a set value, the liquid phase molten salt is stopped from being transported from the molten salt heating tank (50) to the molten salt low temperature tank (37); S3: The molten salt heater (47) is operated to heat the molten salt. When the temperature sent by the fixed thermometer C (52) is T max When the molten salt heater (47) stops working; S4: The molten salt heating tank (50) is used to transport the molten salt to the molten salt constant temperature tank (19). max When the liquid level height sent by the liquid level gauge A (25) reaches a set value h1, the liquid phase molten salt is stopped from being transported from the molten salt heating tank (50) to the molten salt constant temperature tank (19); S5: Use the stirring paddle A to stir the molten salt; transport the molten salt at a temperature of T from the molten salt low temperature tank (37) to the molten salt constant temperature tank (19). min When the liquid level sent by the liquid level gauge A (25) reaches the set value H, the molten salt low temperature tank (37) stops transporting the liquid molten salt to the molten salt constant temperature tank (19); H = h1 + h2, (HH max ) / H max ≥20%, H max is the height value corresponding to the maximum capacity of the molten salt constant temperature tank (19); Where i is the number of the temperature measurement point from high to low of the thermometer being tested, T i is the temperature value of the i-th measurement point; S6: Compare the temperature value T sent by the current fixed thermometer A (23) s With T i , If T s -T i >0, the molten salt low temperature tank (37) intermittently transports the molten salt with a temperature of T to the molten salt constant temperature tank (19). min Liquid molten salt, to Ts = T i When the temperature of the molten salt is high, the liquid phase molten salt is stopped from being transported from the molten salt low temperature tank (37) to the molten salt constant temperature tank (19); If T s -T i <0, the molten salt heating tank (50) intermittently transports the molten salt with a temperature of T to the molten salt constant temperature tank (19). max Liquid molten salt, to Ts = T i When the temperature is high, the liquid phase molten salt is stopped from being transported from the molten salt heating tank (50) to the molten salt constant temperature tank (19); S7: testing the temperature fluctuation and uniformity of the molten salt in the molten salt constant temperature bath (19) according to the specification. When the temperature fluctuation and uniformity meet the requirements, the controller issues a reminder that "calibration test of the i-th temperature point can be started". S8: The inspector inserts the thermometer sample to be tested into the thermometer jack and extends it into the working area (14) to perform calibration inspection; S9: After the inspection is completed, the liquid phase molten salt is transported from the molten salt thermostatic tank (19) to the molten salt recovery tank (71). When the liquid level height sent by the liquid level gauge A (25) reaches the set value h1, the transport of the liquid phase molten salt from the molten salt thermostatic tank (19) to the molten salt recovery tank (71) is stopped; S10: Set i=i+1, perform calibration test at the next temperature point, and repeat steps S5-S9.

10. The method for calibrating a thermometer according to claim 9, characterized in that: T min =160℃,T max =600℃。

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