Small thermostatic bath calibration device

Abstract

The utility model discloses a small thermostatic bath calibration device, which comprises a first height gauge, a second height gauge, a fixed standard platinum resistance thermometer, a movable standard platinum resistance thermometer, a first thermometer adjusting and fixing mechanism and a second thermometer adjusting and fixing mechanism, the movable standard platinum resistance thermometer is inserted into the small thermostatic bath through a second thermometer adjusting and fixing mechanism; the second thermometer adjusting and fixing mechanism comprises a threaded dial, and the threaded dial is provided with an eccentric second open hole used for fixing the movable standard platinum resistance thermometer. The threaded dial can rotate around the threaded sleeve and drive the second open hole to rotate around the center of the threaded dial. According to the calibration device provided by the utility model, four calibration positions of the standard platinum resistance thermometer are positioned and moved by rotating the dial, and compared with a common clamping device, the standard platinum resistance thermometer is not easy to damage and accurate in positioning.

Description

Technical Field

[0001] The utility model relates to the technical field of constant temperature bath calibration. Background Art

[0002] The temperature uniformity and stability of a small thermostatic bath are better as it goes deeper and deeper into the bottom. However, for some small-sized thermometers or those with buckles or flanges, the insertion depth cannot reach the center point or the lower horizontal surface, so calibration can only be performed using the temperature field of the upper horizontal surface of the small thermostatic bath. At this time, the test index of the temperature field of the upper horizontal surface becomes particularly important.

[0003] The traditional thermostatic bath calibration mainly relies on manual operation and the calibration method is not suitable for small portable thermostatic baths. At present, when testing the temperature uniformity of the upper horizontal surface of the thermostatic bath working area, the mobile standard platinum resistance thermometer is inserted into the upper horizontal surface to a depth of not less than 100mm. For some small portable thermostatic baths, this distance is close to the middle and lower layers, and the upper horizontal surface test cannot be achieved.

[0004] Secondly, calibrating the thermostatic bath requires two standard platinum resistance thermometers, which measure the temperature values ​​of a total of 9 different points on the upper and lower horizontal surfaces in turn. The traditional way to fix the thermometer is generally to open a hole in the thermostatic bath cover, and insert the temperature-sensing end of the sensor of the standard platinum resistance thermometer into the thermostatic bath. This method cannot adjust the depth, nor can it calculate the effective working area of ​​the temperature-sensing end inserted into the thermostatic bath, so it cannot accurately measure and calibrate; another method is to fix the standard platinum resistance thermometer on a cantilever rod or a hole plate. Although the thermometer can be raised and lowered, it cannot achieve mobile measurement at 9 different positions. Otherwise, multiple standard platinum resistance thermometers are required to achieve measurement at 9 positions. Multiple standard platinum resistance thermometers are not only expensive, but also the volume of a small thermostatic bath is relatively small, and multiple standard platinum resistance thermometers cannot be placed.

[0005] In addition, most of the calibration of thermostatic baths is done manually, which is not only time-consuming but also prone to human errors. Now, precision temperature measurement bridges can realize the automatic data collection function of thermometers, eliminating the need for manual counting at different temperature points, different locations and different times. Summary of the invention

[0006] The technical problem to be solved by the utility model is to provide a small constant temperature bath calibration device which is simple to operate and easy to accurately position.

[0007] In order to solve the above technical problems, the technical solution of the utility model is:

[0008] The utility model first provides a small thermostatic bath calibration device, comprising a first height gauge, a second height gauge, a fixed standard platinum resistance thermometer, a mobile standard platinum resistance thermometer, a first thermometer adjustment and fixing mechanism, and a second thermometer adjustment and fixing mechanism; the fixed standard platinum resistance thermometer is inserted into the small thermostatic bath through the first thermometer adjustment and fixing mechanism, and the mobile standard platinum resistance thermometer is inserted into the small thermostatic bath through the second thermometer adjustment and fixing mechanism;

[0009] The first thermometer adjustment and fixing mechanism includes a first guide sleeve, a first limit screw, a first fixing screw, a first telescopic rod and a first threaded slot; the first guide sleeve is arranged on the first height gauge and can slide up and down along the first height gauge, and the first limit screw is used to fix the first guide sleeve on the first height gauge at a required height; the first telescopic rod is fixed to the first guide sleeve by the first fixing screw; the first telescopic rod includes a first fixing rod, a first moving rod and a first locking frame, the fixing rod and the moving rod are connected by the first locking frame, and the telescopic length of the first telescopic rod is adjusted by the first locking frame; the first threaded slot is fixed to the end of the first telescopic rod, and a first opening for fixing a standard platinum resistance thermometer is provided on the first threaded slot;

[0010] The second thermometer adjustment and fixing mechanism comprises a second guide sleeve, a second limit screw, a second fixing screw, a second telescopic rod, a second threaded slot, a threaded sleeve and a threaded dial; the second guide sleeve is arranged on the second height gauge and can slide up and down along the second height gauge, and the second limit screw is used to fix the second guide sleeve on the second height gauge at a required height; the second telescopic rod is fixed to the second guide sleeve by the second fixing screw; the second telescopic rod comprises a second fixing rod, a second moving rod and a second locking frame, the second fixing rod and the second moving rod are connected by the second locking frame, and the telescopic length of the second telescopic rod is adjusted by the second locking frame; the second threaded slot is fixed to the end of the second telescopic rod, the threaded sleeve is arranged on the second threaded slot, the threaded dial is arranged at the upper end of the threaded sleeve, and an eccentric second opening for fixing and moving a standard platinum resistance thermometer is arranged on the threaded dial; the threaded dial can rotate around the threaded sleeve and drive the second opening to rotate around the center of the threaded dial.

[0011] The first guide sleeve and the second guide sleeve have the same structure.

[0012] The first telescopic rod and the second telescopic rod have the same structure.

[0013] It also includes: a temperature measuring bridge, wherein the precision temperature measuring bridge is used to measure the temperature values ​​of the fixed standard platinum resistance thermometer and the mobile standard platinum resistance thermometer.

[0014] It also includes: a computer, which is used to control the precision temperature measurement bridge to collect data.

[0015] The utility model also provides a small constant temperature bath calibration method of a small constant temperature bath calibration device, comprising:

[0016] Before starting the thermostatic bath calibration, determine the depth of the first height gauge according to the depth of the thermostatic bath, so that the fixed standard platinum resistance thermometer is vertically suspended at the center of the thermostatic bath; the second height gauge clamps the mobile standard platinum resistance thermometer, and the mobile standard platinum resistance thermometer is positioned at the first position A of the upper horizontal plane through the second opening on the threaded dial, and is vertically suspended at the upper horizontal plane position of the thermostatic bath; set the first temperature point of the thermostatic bath, and after the temperature stabilizes, the upper horizontal plane depth is continuously increased by the height gauge to increase the depth of the mobile platinum resistance thermometer, and after the maximum temperature difference and height pre-determination criteria are met, fix the height gauge, and finally determine the upper horizontal plane depth and the first position A of the upper horizontal plane of the mobile platinum resistance thermometer through uncertainty evaluation verification; the wiring terminals of the fixed standard platinum resistance thermometer and the mobile standard platinum resistance thermometer are connected to the precision temperature measuring bridge;

[0017] When calibrating the upper horizontal surface of the thermostatic bath, the computer controls the temperature measuring bridge to determine whether the fixed standard platinum resistance thermometer and the mobile standard platinum resistance thermometer meet the automatic reading conditions and collect data through the temperature stability pre-determination criteria; after the measurement of the first position A of the upper horizontal surface is completed, the mobile platinum resistance thermometer is adjusted and positioned at the second position B of the upper horizontal surface by rotating the threaded dial; the computer controls the temperature measuring bridge to determine whether the fixed standard platinum resistance thermometer and the mobile standard platinum resistance thermometer meet the automatic reading conditions and read the data through the temperature stability pre-determination criteria; after the measurement of the second position B of the upper horizontal surface is completed, the mobile platinum resistance thermometer is adjusted and positioned at the water level of the right jack by rotating the threaded dial The third position C of the plane; the computer controls the temperature measuring bridge to determine whether the fixed standard platinum resistance thermometer and the mobile standard platinum resistance thermometer meet the automatic reading and collect data through the temperature stability pre-determination criteria; after the measurement of the third position C of the upper horizontal plane is completed, the mobile platinum resistance thermometer is adjusted and positioned at the fourth position D of the upper horizontal plane by rotating the threaded dial; the computer (controls the precision temperature measuring bridge to determine whether the fixed standard platinum resistance thermometer and the mobile standard platinum resistance thermometer meet the automatic reading through the temperature stability pre-determination criteria; the upper horizontal plane calibration is completed; the first position A of the upper horizontal plane, the second position B of the upper horizontal plane, the third position C of the upper horizontal plane and the fourth position D of the upper horizontal plane are alternated by 90° in sequence;

[0018] Before calibrating the lower horizontal surface of the thermostatic bath, first lower the mobile platinum resistance thermometer to the bottom of the thermostatic bath by lowering the depth using the height gauge; and position it at the first position E of the lower horizontal surface of the jack by rotating the threaded dial;

[0019] When calibrating the lower horizontal surface of the constant temperature bath, the computer controls the temperature measuring bridge to determine whether the fixed standard platinum resistance thermometer and the mobile standard platinum resistance thermometer meet the automatic reading requirements through the temperature stability pre-determination criteria; after the measurement of the first position E of the lower horizontal surface is completed, the mobile platinum resistance thermometer is adjusted and positioned at the lower horizontal surface F position of the rear jack by rotating the threaded dial; the computer controls the temperature measuring bridge to determine whether the fixed standard platinum resistance thermometer and the mobile standard platinum resistance thermometer meet the automatic reading requirements through the temperature stability pre-determination criteria; after the measurement of the second position F of the lower horizontal surface is completed, the mobile platinum resistance thermometer is adjusted and positioned at the lower horizontal surface F position of the rear jack by rotating the threaded dial Positioned at the third position G of the lower horizontal plane; the computer controls the precision temperature measuring bridge to determine whether the automatic reading is satisfied through the temperature stability pre-determination criteria; after the measurement of the third position G of the lower horizontal plane is completed, the mobile platinum resistance thermometer is adjusted and positioned at the fourth position H of the lower horizontal plane by rotating the threaded dial; the computer controls the temperature measuring bridge to determine whether the fixed standard platinum resistance thermometer and the mobile standard platinum resistance thermometer meet the automatic reading through the temperature stability pre-determination criteria; the calibration of the lower horizontal plane is completed; the first position E of the lower horizontal plane, the second position F of the lower horizontal plane, the third position G of the lower horizontal plane and the fourth position H of the lower horizontal plane are alternated by 90° in sequence;

[0020] After the uniformity measurement of the upper and lower horizontal surfaces of the thermostatic bath at a certain temperature point is completed, change to the next calibration temperature point and repeat the above steps until the uniformity test of the thermostatic bath at different calibration points is completed.

[0021] The maximum temperature difference and height pre-determination criteria are:

[0022] S1. Obtain the effective working area depth of the small thermostatic bath, calculate its center point depth, and adjust the fixed standard platinum resistance thermometer to the center point depth through the height gauge;

[0023] S2. Adjust the starting value of the upper horizontal plane depth of the mobile standard platinum resistance thermometer by using the height gauge, calculate the horizontal temperature difference of the upper horizontal plane by the relationship between the depth and the data of the mobile standard platinum resistance thermometer, and preliminarily judge the upper horizontal plane depth of the mobile standard platinum resistance thermometer;

[0024] S3. Verify the uncertainty of the measurement results of the mobile standard platinum resistance thermometer at the initial depth, and evaluate the effective reliability of the calibration thermostat at this depth;

[0025] S4. Obtain the uniformity of the temperature field on the horizontal surface under the small constant temperature bath by moving a standard platinum resistance thermometer, and calculate the horizontal temperature difference and the maximum temperature difference;

[0026] S5. Calculate the temperature stability of the small thermostatic bath by collecting the temperature values ​​at the center of different temperature points using a fixed standard platinum resistance thermometer.

[0027] Initially determine the depth of the horizontal surface on the mobile standard platinum resistance thermometer;

[0028] T A -T0≤T max

[0029] Among them, T A is the temperature value of the mobile standard platinum resistance after thermal equilibrium at position A; T0 is the center point temperature value obtained by the fixed standard platinum resistance thermometer; T max To predict the maximum temperature difference.

[0030] The uncertainty U of the measurement result uncertainty of the mobile standard platinum resistance thermometer at the initial depth is:

[0031]

[0032] Among them, u1 is the standard uncertainty component introduced by the repeatability of the mobile standard platinum resistance thermometer; u2 is the standard uncertainty component introduced by the resolution of the two standard platinum resistance thermometers; u3 is the standard uncertainty component introduced by the stability of the two standard platinum resistance thermometers; u4 is the standard uncertainty component introduced by the temperature measurement bridge; u5 is the standard uncertainty component introduced by two different measuring holes; T max It is the technical indicator of the stability of the constant temperature bath.

[0033] Compared with the prior art, the beneficial effects of the utility model are:

[0034] The calibration device of the utility model can realize the calibration of a small thermostatic bath with only two platinum resistance thermometers, saving manpower and materials. The standard platinum resistance thermometer is expensive and is a quartz product that is fragile. The internal platinum wire itself will produce stress when it is vibrated or collided, which will cause the drift of the measurement characteristics. The four calibration positions of the standard platinum resistance thermometer are positioned and moved by rotating the dial. Compared with the common clamping device, the standard platinum resistance thermometer is not easy to be damaged and has accurate positioning.

[0035] According to the existing practice of calibrating the thermostatic bath, the mobile standard platinum resistance thermometer is inserted into the upper horizontal surface to a depth of not less than 100mm. This distance is too deep to achieve the temperature field uniformity test of the upper horizontal surface of the small portable thermostatic bath. The method of the utility model uses a height ruler to change the mobile standard platinum resistance thermometer, and calculates the horizontal temperature difference result of the upper horizontal surface at the initial depth through the relationship between the depth and the data of the mobile standard platinum resistance thermometer. Then, the temperature field uniformity test of the upper horizontal surface of the small portable thermostatic bath can be achieved at the initial depth through uncertainty evaluation, thereby determining the final upper horizontal surface insertion depth of the mobile standard platinum resistance thermometer. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1A schematic diagram of the structure of a calibration device according to Embodiment 1 of the present utility model;

[0037] Figure 2 A diagram showing the movement sequence of a standard platinum resistance thermometer during the calibration process of the calibration device of Embodiment 1 of the utility model;

[0038] Figure 3 A schematic diagram of the calibration process of the utility model;

[0039] In the figure: height gauges 1 and 16, limit screws 2, fixing screws 3, locking frame 4, telescopic rod 5, threaded slots 6, openings 7, fixed standard platinum resistance thermometer 8, mobile standard platinum resistance thermometer 9, threaded sleeve 10, threaded dial 11, openings 12, precision temperature measuring bridge 13, computer 14, constant temperature bath 15. DETAILED DESCRIPTION

[0040] This embodiment provides a small constant temperature bath calibration device, such as Figure 1 The small thermostatic bath calibration device comprises a first height gauge 1, a second height gauge 16, a fixed standard platinum resistance thermometer 8, a mobile standard platinum resistance thermometer 9, a first thermometer adjustment and fixing mechanism, and a second thermometer adjustment and fixing mechanism; the fixed standard platinum resistance thermometer 8 is inserted into the small thermostatic bath through the first thermometer adjustment and fixing mechanism, and the mobile standard platinum resistance thermometer 9 is inserted into the small thermostatic bath through the second thermometer adjustment and fixing mechanism;

[0041] The first thermometer adjustment and fixing mechanism includes a first guide sleeve, a first limit screw 2, a first fixing screw 3, a first telescopic rod 5 and a first threaded slot 6; the first guide sleeve is arranged on the first height gauge 1 and can slide up and down along the first height gauge, and the first limit screw 2 is used to fix the first guide sleeve on the first height gauge 1 at a required height; the first telescopic rod 5 is fixed to the first guide sleeve by the first fixing screw 3; the first telescopic rod 5 includes a first fixing rod, a first moving rod and a first locking frame 4, the fixing rod and the moving rod are connected by the first locking frame 4, and the telescopic length of the first telescopic rod 5 is adjusted by the first locking frame 4; the first threaded slot 6 is fixed to the end of the first telescopic rod 5, and a first opening 7 for fixing a standard platinum resistance thermometer 8 is provided on the first threaded slot 6;

[0042] The second thermometer adjustment and fixing mechanism includes a second guide sleeve, a second limit screw, a second fixing screw, a second telescopic rod, a second threaded slot, a threaded sleeve 10 and a threaded dial 11; the second guide sleeve is arranged on the second height gauge 16 and can slide up and down along the second height gauge, and the second limit screw is used to fix the second guide sleeve on the second height gauge 16 at the required height; the second telescopic rod is fixed to the second guide sleeve by the second fixing screw; the second telescopic rod includes a second fixing rod, a second moving rod and a second locking frame, and the second The two fixed rods and the second movable rod are connected by a second locking frame, and the telescopic length of the second telescopic rod is adjusted by the second locking frame; the second threaded slot is fixed to the end of the second telescopic rod, the threaded sleeve 10 is arranged on the second threaded slot, the threaded dial 11 is arranged on the upper end of the threaded sleeve 10, and an eccentric second opening 12 for fixing a movable standard platinum resistance thermometer 9 is arranged on the threaded dial 11; the threaded dial 11 can rotate around the threaded sleeve 10 and drive the second opening 12 to rotate around the center of the threaded dial 11.

[0043] The first guide sleeve and the second guide sleeve have the same structure.

[0044] The first telescopic rod 5 has the same structure as the second telescopic rod.

[0045] It also includes: a temperature measuring bridge 13 , wherein the precision temperature measuring bridge 13 is used to measure the temperature values ​​of the fixed standard platinum resistance thermometer 8 and the mobile standard platinum resistance thermometer 9 .

[0046] The computer 14 is used to control the precise temperature measuring bridge 13 to collect data.

[0047] This embodiment provides

[0048] The utility model also provides a small constant temperature bath calibration method for a small constant temperature bath calibration device, such as Figure 2 and Figure 3 As shown, the calibration method includes:

[0049] Before starting the thermostatic bath calibration, determine the depth of the first height gauge according to the depth of the thermostatic bath, so that the fixed standard platinum resistance thermometer is vertically suspended at the center of the thermostatic bath; the second height gauge clamps the mobile standard platinum resistance thermometer, and the mobile standard platinum resistance thermometer is positioned at the first position A of the upper horizontal plane through the second opening on the threaded dial, and is vertically suspended at the upper horizontal plane position of the thermostatic bath; set the first temperature point of the thermostatic bath, and after the temperature stabilizes, the upper horizontal plane depth is continuously increased by the height gauge to increase the depth of the mobile platinum resistance thermometer, and after the maximum temperature difference and height pre-determination criteria are met, fix the height gauge, and finally determine the upper horizontal plane depth and the first position A of the upper horizontal plane of the mobile platinum resistance thermometer through uncertainty evaluation verification; the wiring terminals of the fixed standard platinum resistance thermometer and the mobile standard platinum resistance thermometer are connected to the precision temperature measuring bridge;

[0050] When calibrating the upper horizontal surface of the thermostatic bath, the computer controls the temperature measuring bridge to determine whether the fixed standard platinum resistance thermometer and the mobile standard platinum resistance thermometer meet the automatic reading conditions and collect data through the temperature stability pre-determination criteria; after the measurement of the first position A of the upper horizontal surface is completed, the mobile platinum resistance thermometer is adjusted and positioned at the second position B of the upper horizontal surface by rotating the threaded dial; the computer controls the temperature measuring bridge to determine whether the fixed standard platinum resistance thermometer and the mobile standard platinum resistance thermometer meet the automatic reading conditions and read the data through the temperature stability pre-determination criteria; after the measurement of the second position B of the upper horizontal surface is completed, the mobile platinum resistance thermometer is adjusted and positioned at the water level of the right jack by rotating the threaded dial The third position C of the plane; the computer controls the temperature measuring bridge to determine whether the fixed standard platinum resistance thermometer and the mobile standard platinum resistance thermometer meet the automatic reading and collect data through the temperature stability pre-determination criteria; after the measurement of the third position C of the upper horizontal plane is completed, the mobile platinum resistance thermometer is adjusted and positioned at the fourth position D of the upper horizontal plane by rotating the threaded dial; the computer (controls the precision temperature measuring bridge to determine whether the fixed standard platinum resistance thermometer and the mobile standard platinum resistance thermometer meet the automatic reading through the temperature stability pre-determination criteria; the upper horizontal plane calibration is completed; the first position A of the upper horizontal plane, the second position B of the upper horizontal plane, the third position C of the upper horizontal plane and the fourth position D of the upper horizontal plane are alternated by 90° in sequence;

[0051] Before calibrating the lower horizontal surface of the thermostatic bath, first lower the mobile platinum resistance thermometer to the bottom of the thermostatic bath by lowering the depth using the height gauge; and position it at the first position E of the lower horizontal surface of the jack by rotating the threaded dial;

[0052] When calibrating the lower horizontal surface of the constant temperature bath, the computer controls the temperature measuring bridge to determine whether the fixed standard platinum resistance thermometer and the mobile standard platinum resistance thermometer meet the automatic reading requirements through the temperature stability pre-determination criteria; after the measurement of the first position E of the lower horizontal surface is completed, the mobile platinum resistance thermometer is adjusted and positioned at the lower horizontal surface F position of the rear jack by rotating the threaded dial; the computer controls the temperature measuring bridge to determine whether the fixed standard platinum resistance thermometer and the mobile standard platinum resistance thermometer meet the automatic reading requirements through the temperature stability pre-determination criteria; after the measurement of the second position F of the lower horizontal surface is completed, the mobile platinum resistance thermometer is adjusted and positioned at the lower horizontal surface F position of the rear jack by rotating the threaded dial Positioned at the third position G of the lower horizontal plane; the computer controls the precision temperature measuring bridge to determine whether the automatic reading is satisfied through the temperature stability pre-determination criteria; after the measurement of the third position G of the lower horizontal plane is completed, the mobile platinum resistance thermometer is adjusted and positioned at the fourth position H of the lower horizontal plane by rotating the threaded dial; the computer controls the temperature measuring bridge to determine whether the fixed standard platinum resistance thermometer and the mobile standard platinum resistance thermometer meet the automatic reading through the temperature stability pre-determination criteria; the calibration of the lower horizontal plane is completed; the first position E of the lower horizontal plane, the second position F of the lower horizontal plane, the third position G of the lower horizontal plane and the fourth position H of the lower horizontal plane are alternated by 90° in sequence;

[0053] After the uniformity measurement of the upper and lower horizontal surfaces of the thermostatic bath at a certain temperature point is completed, change to the next calibration temperature point and repeat the above steps until the uniformity test of the thermostatic bath at different calibration points is completed.

[0054] The calibration method is to calibrate the temperature at each temperature measuring point, including the following steps:

[0055] S1. Obtain the effective working area depth of the small thermostatic bath, calculate its center point depth, and adjust the fixed standard platinum resistance thermometer to the center point depth through the height gauge;

[0056] S2. Adjust the starting value of the upper horizontal plane depth of the mobile standard platinum resistance thermometer by using the height gauge, calculate the horizontal temperature difference of the upper horizontal plane by the relationship between the depth and the data of the mobile standard platinum resistance thermometer, and preliminarily judge the upper horizontal plane depth of the mobile standard platinum resistance thermometer;

[0057] S3. Verify the uncertainty of the measurement results of the mobile standard platinum resistance thermometer at the initial depth, and evaluate the effective reliability of the calibration thermostat at this depth;

[0058] S4. Obtain the uniformity of the temperature field on the horizontal surface under the small constant temperature bath by moving a standard platinum resistance thermometer, and calculate the horizontal temperature difference and the maximum temperature difference;

[0059] S5. Calculate the temperature stability of the small thermostatic bath by collecting the temperature values ​​at the center of different temperature points using a fixed standard platinum resistance thermometer.

[0060] The step S2 of calculating the horizontal temperature difference of the upper horizontal surface by the relationship between the depth and the data of the mobile standard platinum resistance thermometer and preliminarily judging the depth of the upper horizontal surface of the mobile standard platinum resistance thermometer includes:

[0061] S21. It is known that the length of the temperature sensing element of the standard platinum resistance thermometer is 40 mm, so the insertion depth of the mobile standard platinum resistance thermometer used to calibrate the small constant temperature bath must be at least 40 mm.

[0062] S22. After the mobile standard platinum resistance thermometer reaches thermal equilibrium, the insertion depth is continuously increased by 10 mm. After thermal equilibrium is reached again, the temperature fluctuation does not exceed the predicted maximum temperature difference.

[0063] The verification of the uncertainty of the measurement result of the mobile standard platinum resistance thermometer at the initial depth in step S3 includes the following steps:

[0064] S31. Analyze the sources of uncertainty from the equipment required for calibrating a small thermostatic bath: standard uncertainty components introduced by the repeatability of the mobile standard platinum resistance thermometer, standard uncertainty components introduced by the resolution of the two standard platinum resistance thermometers, standard uncertainty components introduced by the stability of the two standard platinum resistance thermometers, standard uncertainty components introduced by the precision temperature measurement bridge, and standard uncertainty components introduced by two different measuring holes;

[0065] S32. After synthesizing all standard uncertainty components, the uncertainty of the measurement result of the horizontal temperature difference at a certain depth is evaluated to be no more than one-third of the technical indicator of the stability of the small constant temperature bath.

[0066] Steps S4 and S5 are conventional calibration steps and will not be repeated.

[0067] Step S1: Select two standard platinum resistance thermometers, one as a fixed standard platinum resistance thermometer and the other as a mobile thermometer. Connect the temperature measuring bridge for measurement. Use a height gauge to adjust the fixed standard platinum resistance thermometer to the center point O of the working area of ​​the small thermostatic bath, and obtain the center point temperature value T0;

[0068] Step S2: The mobile standard platinum resistance thermometer is placed at point A on the working area of ​​the small thermostatic bath. The starting value of the depth of the horizontal surface on the mobile standard platinum resistance thermometer is adjusted to 40 mm by using a height gauge. By continuously increasing the depth and the relationship between the data of the mobile standard platinum resistance thermometer, after the mobile standard platinum resistance thermometer reaches thermal equilibrium, T A , calculate the horizontal temperature difference of the upper horizontal surface, satisfying the temperature fluctuation T A -T0 does not exceed the predicted maximum temperature difference T max , this height is the depth of the horizontal surface of the standard platinum resistance thermometer used for preliminary judgment;

[0069] TA -T0≤T max

[0070] Step S3 calculates the combined result uncertainty U from the standard uncertainty component u1 introduced by the repeatability of the mobile standard platinum resistance thermometer, the standard uncertainty component u2 introduced by the resolution of the two standard platinum resistance thermometers, the standard uncertainty component u3 introduced by the stability of the two standard platinum resistance thermometers, the standard uncertainty component u4 introduced by the precision temperature measurement bridge, and the standard uncertainty component u5 introduced by two different measuring holes. Verify the uncertainty of the measurement result of the mobile standard platinum resistance thermometer at the initial depth, and evaluate the effective reliability of the thermostatic bath when calibrating the thermostatic bath at this depth, that is, the combined uncertainty is less than or equal to the technical index T of the stability of the small thermostatic bath max one third of.

[0071]

[0072] Step S4 obtains the uniformity of the temperature field on the horizontal surface under the small constant temperature bath by moving a standard platinum resistance thermometer, and calculates the horizontal temperature difference and the maximum temperature difference;

[0073] In step S5, the temperature stability of the small thermostatic bath is calculated by collecting the temperature values ​​of the center positions of different temperature points using a fixed standard platinum resistance thermometer.

Claims

1. A small thermostatic bath calibration device, characterized in that: The device comprises a first height gauge (1), a second height gauge (16), a fixed standard platinum resistance thermometer (8), a movable standard platinum resistance thermometer (9), a first thermometer adjustment and fixing mechanism, and a second thermometer adjustment and fixing mechanism; the fixed standard platinum resistance thermometer (8) is inserted into a small constant temperature bath via the first thermometer adjustment and fixing mechanism, and the movable standard platinum resistance thermometer (9) is inserted into the small constant temperature bath via the second thermometer adjustment and fixing mechanism; The first thermometer adjustment and fixing mechanism comprises a first guide sleeve, a first limit screw (2), a first fixing screw (3), a first telescopic rod (5) and a first threaded groove (6); the first guide sleeve is arranged on the first height gauge (1) and can slide up and down along the first height gauge; the first limit screw (2) is used to fix the first guide sleeve on the first height gauge (1) at a required height; the first telescopic rod (5) is fixed to the first guide sleeve by the first fixing screw (3); the first telescopic rod (5) comprises a first fixing rod, a first moving rod and a first locking frame (4); the fixing rod and the moving rod are connected by the first locking frame (4); the telescopic length of the first telescopic rod (5) is adjusted by the first locking frame (4); the first threaded groove (6) is fixed to the end of the first telescopic rod (5); a first opening (7) for fixing a standard platinum resistance thermometer (8) is provided on the first threaded groove (6); The second thermometer adjustment and fixing mechanism comprises a second guide sleeve, a second limit screw, a second fixing screw, a second telescopic rod, a second threaded slot, a threaded sleeve (10) and a threaded dial (11); the second guide sleeve is arranged on the second height gauge (16) and can slide up and down along the second height gauge, and the second limit screw is used to fix the second guide sleeve on the second height gauge (16) at a required height; the second telescopic rod is fixed to the second guide sleeve by the second fixing screw; the second telescopic rod comprises a second fixing rod, a second moving rod and a second locking frame, and the second fixing rod and the second moving rod are connected to the second height gauge (16) at a desired height. The two moving rods are connected by a second locking frame, and the telescopic length of the second telescopic rod is adjusted by the second locking frame; the second threaded slot is fixed to the end of the second telescopic rod, the threaded sleeve (10) is arranged on the second threaded slot, the threaded dial (11) is arranged at the upper end of the threaded sleeve (10), and an eccentric second opening (12) for fixing a mobile standard platinum resistance thermometer (9) is arranged on the threaded dial (11); the threaded dial (11) can rotate around the threaded sleeve (10) and drive the second opening (12) to rotate around the center of the threaded dial (11).

2. The small constant temperature bath calibration device according to claim 1, characterized in that: The first guide sleeve and the second guide sleeve have the same structure.

3. The small constant temperature bath calibration device according to claim 1, characterized in that: The first telescopic rod (5) and the second telescopic rod have the same structure.

4. The small constant temperature bath calibration device according to any one of claims 1 to 3, characterized in that: Also includes: A temperature measuring bridge (13) is used to measure the temperature values ​​of a fixed standard platinum resistance thermometer (8) and a mobile standard platinum resistance thermometer (9).

5. The small constant temperature bath calibration device according to claim 4, characterized in that: Also includes: A computer (14), the computer (14) is used to control the temperature measuring bridge (13) to collect data.

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