Calibration tool and calibration method for temperature sensor in liquid helium temperature zone

Abstract

The invention provides a calibration tool for a temperature sensor in a liquid helium temperature region and a calibration method thereof. The calibration tool comprises a cold guide plate, a heat conduction column and a connecting rod which are arranged in a Dewar flask, and a corrugated pipe and a pull rod which are arranged outside the Dewar flask, a plurality of mounting holes for placing the temperature sensors are formed in the cold guide plate, and the cold guide plate is used for conducting the cold quantity of the refrigerating device to the temperature sensors in the refrigerating stage and further used for conducting the heat of the heat conduction columns to the temperature sensors in the heating and rewarming stage; one end of the heat conduction column is connected with one end of the cold conduction plate, and the other end of the heat conduction column is connected with one end of the connecting rod. One end of the corrugated pipe is hermetically connected with the bottom of the Dewar; one end of the pull rod is inserted into the Dewar and connected with the other end of the connecting rod; and the middle of the pull rod is hermetically connected with the other end of the corrugated pipe. According to the invention, the technical problems of low calibration precision, low efficiency and unstable rewarming process of the temperature sensor in the prior art can be solved.

Description

Technical Field

[0001] The invention relates to the technical field of temperature sensor calibration, and in particular to a calibration tool for a temperature sensor in a liquid helium temperature zone and a calibration method thereof. Background Art

[0002] Temperature sensors used in the cryogenic liquid helium temperature range (4K temperature range) are generally resistive temperature sensors, which exhibit different resistance characteristics at different temperatures. Accurate temperature measurements can be obtained by measuring the resistance of the sensor and comparing the resistance-temperature characteristic curve (temperature calibration curve).

[0003] Generally, the temperature calibration curve of a resistive temperature sensor is a linear curve, and different batches and different sensors can basically use the same curve. However, due to its special extremely low temperature characteristics in the liquid helium temperature zone, the calibration curve of the resistive temperature sensor in this temperature zone is nonlinear, and the characteristic curves between sensors from different batches and between different sensors in the same batch are also significantly different. Therefore, for resistive temperature sensors that measure liquid helium temperature zones, the sensors need to be calibrated in advance to obtain an accurate temperature calibration curve before they can be officially used and accurately measured.

[0004] At present, for the calibration of temperature sensors in the liquid helium temperature zone, the sensor to be calibrated and the standard sensor are fixed on the sensor fixing fixture at the same time. The fixture is connected to the cold end of a special refrigerator and placed in a special sealing test dewar. The fixture and the sensor are cooled to the technically required temperature (generally 1.4K~4K) through the cold end of the refrigerator. The refrigerator is turned off, and during the rewarming process of the fixed fixture, the resistance of the sensor to be calibrated and the temperature measured by the standard sensor are measured to form the temperature-resistance characteristic curve (temperature calibration curve) of the sensor to be calibrated.

[0005] The existing calibration method has the following three disadvantages:

[0006] (1) Since the refrigerator is connected to the external normal temperature end, it has a large heat leakage. Therefore, after the refrigeration is turned off, the sensor fixture connected to it will quickly recover and the overall temperature will be uneven, which may cause a temperature difference between the sensor to be calibrated and the standard sensor, resulting in reduced calibration accuracy;

[0007] (2) The sensor fixture is generally made of metal materials with good thermal conductivity, such as copper. Such metal materials have a small heat capacity at extremely low temperatures (generally below 30K) and a high heat capacity at high temperatures (generally above 77K). This causes the low temperature zone to recover too quickly and the high temperature zone to recover too slowly during the re-temperature calibration process. The overall re-temperature process is unstable, and the sensor calibration efficiency is low.

[0008] (3) The sensor is generally fixed to the surface of the tooling with thermal conductive silicone grease to ensure that the sensor can be removed and reused smoothly and completely after calibration. This installation method results in insufficient contact between the sensor and the tooling, poor thermal conductivity, and reduced calibration accuracy. Summary of the invention

[0009] The present invention provides a calibration tool and a calibration method for a temperature sensor in a liquid helium temperature zone, which can solve the technical problems of low calibration accuracy, low efficiency and unstable rewarming history of the temperature sensor in the prior art.

[0010] According to one aspect of the present invention, a calibration tool for a temperature sensor in a liquid helium temperature zone is provided, the tool comprising a cold plate, a heat conducting column, a connecting rod arranged inside the dewar, and a bellows and a pull rod arranged outside the dewar;

[0011] The cold conduction plate is provided with a plurality of mounting holes for placing the temperature sensor, and the cold conduction plate is used to conduct the cold of the refrigeration device to the temperature sensor in the refrigeration stage, and is also used to conduct the heat of the heat conduction column to the temperature sensor in the heating and reheating stage;

[0012] One end of the heat-conducting column is connected to one end of the cold-conducting plate, and the other end is connected to one end of the connecting rod, and the heat-conducting column is self-heated by a heating device;

[0013] One end of the bellows is sealed and connected to the bottom of the Dewar;

[0014] One end of the pull rod is inserted into the Dewar and connected to the other end of the connecting rod. The middle part of the pull rod is sealed and connected to the other end of the bellows. The pull rod is pulled in a direction away from the cold end of the refrigeration device to drive the bellows to extend, and at the same time drive the connecting rod, the heat conduction column, the cold conduction plate and the pull rod to move in the same direction, so that the cold conduction plate is separated from the cold end of the refrigeration device, thereby achieving the transition from the calibrated refrigeration stage to the natural rewarming stage.

[0015] Preferably, the cooling plate is in the shape of a flat cylinder.

[0016] Preferably, the plurality of mounting holes are evenly arranged on the outer wall of the flat cylinder along the circumferential direction.

[0017] Preferably, the heating device adopts a flexible heating sheet, and the flexible heating sheet is located in the Dewar and wrapped around the outer wall of the heat-conducting column.

[0018] Preferably, the diameter of the heat-conducting column is the same as the diameter of the connecting rod, and the height of the heat-conducting column is the same as the width of the flexible heating sheet.

[0019] Preferably, the refrigeration device adopts a refrigerator, the cold end of which is located in the Dewar, providing cold air for the cold conduction plate during the refrigeration stage.

[0020] Preferably, the connecting rod is a composite rod.

[0021] Preferably, the composite rod is made of glass fiber or carbon fiber.

[0022] Preferably, the material of the bellows is the same as that of the Dewar.

[0023] According to another aspect of the present invention, a calibration method for a calibration tool for a temperature sensor in a liquid helium temperature zone is provided, wherein the method uses any of the above-mentioned tools for calibration, and the method comprises:

[0024] Install a standard temperature sensor and a plurality of temperature sensors to be calibrated in the mounting holes of the cold conduction plate;

[0025] When the cold conducting plate is in contact with the cold end of the refrigeration device, the cold conducting plate is cooled to a preset temperature by the refrigeration device so that all temperature sensors in the cold conducting plate are at the preset temperature;

[0026] Pull the pull rod in a direction away from the cold end of the refrigeration device to extend the bellows, thereby separating the cold conduction plate from the cold end of the refrigeration device, so that the calibration tooling is in a natural rewarming stage;

[0027] When the calibration tool is in the natural rewarming stage, a plurality of temperature sensors to be calibrated are calibrated by a standard temperature sensor to obtain temperature calibration curves of the plurality of temperature sensors to be calibrated in the natural rewarming stage;

[0028] The cold conduction plate is heated by a heating device so that the calibration tooling is in a heating and re-warming stage;

[0029] When the calibration tool is in the heating and reheating stage, a plurality of temperature sensors to be calibrated are calibrated by a standard temperature sensor to obtain temperature calibration curves of the plurality of temperature sensors to be calibrated in the heating and reheating stage;

[0030] Based on the temperature calibration curves of the multiple temperature sensors to be calibrated in the natural rewarming stage and the temperature calibration curves of the multiple temperature sensors to be calibrated in the heating rewarming stage, the temperature calibration curves of the multiple temperature sensors to be calibrated in the full temperature range are obtained.

[0031] Preferably, the preset temperature ranges from 1.4 to 4K.

[0032] Preferably, when the rewarming temperature in the natural rewarming stage is between 30K and 77K and the rewarming rate is less than a preset value, the heating device is turned on.

[0033] Preferably, calibrating multiple temperature sensors to be calibrated by using a standard temperature sensor to obtain temperature calibration curves of the multiple temperature sensors to be calibrated in the natural rewarming stage includes:

[0034] At every preset time interval or when the standard sensor rises to a preset temperature, the resistance values ​​of the multiple temperature sensors to be calibrated and the temperature value of the standard temperature sensor at the current moment are obtained;

[0035] Based on the one-to-one corresponding resistance values ​​and temperature values ​​at each moment, temperature calibration curves of multiple temperature sensors to be calibrated in the natural rewarming stage are obtained.

[0036] Preferably, calibrating a plurality of temperature sensors to be calibrated by a standard temperature sensor to obtain temperature calibration curves of the plurality of temperature sensors to be calibrated in the heating and reheating stage includes:

[0037] At every preset time interval or when the standard sensor rises to a preset temperature, the resistance values ​​of the multiple temperature sensors to be calibrated and the temperature value of the standard temperature sensor at the current moment are obtained;

[0038] Based on the one-to-one corresponding resistance values ​​and temperature values ​​at each moment, temperature calibration curves of multiple temperature sensors to be calibrated in the heating and reheating stage are obtained.

[0039] By applying the technical solution of the present invention, the connection relationship between the cold plate, the heat-conducting column, the connecting rod, the bellows and the pull rod is designed, so that the calibration tooling has different connection structures in the refrigeration stage and the rewarming stage, and has different rewarming heat sources. On the one hand, the refrigeration device and the cold plate are separated in the low-temperature natural rewarming process, the heat leakage of the refrigeration device is isolated, the rewarming speed of the cold plate is reduced, the temperature distribution uniformity of the calibration tooling and the calibration accuracy of the sensor in the low-temperature zone are improved; on the other hand, a small heat input is provided by the connecting rod in the low-temperature natural rewarming stage, and a large heat input is provided by the heating device and the heat-conducting column in the high-temperature heating rewarming stage, which stabilizes the sensor calibration rewarming process and improves the sensor calibration efficiency; on the other hand, the temperature sensor is embedded in the cold plate, so that the sensor and the calibration tooling are fully in contact, with good heat conduction efficiency, and the sensor calibration accuracy is improved. The present invention is suitable for calibrating temperature sensors in the low-temperature liquid helium temperature zone (4K temperature zone), and solves the problems of low sensor calibration accuracy, low and unstable calibration process efficiency, and low heat conduction efficiency between the sensor and the tooling. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The included drawings are used to provide a further understanding of the embodiments of the present invention, which constitute a part of the specification, are used to illustrate the embodiments of the present invention, and together with the text description, explain the principles of the present invention. Obviously, the drawings in the following description are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0041] Figure 1 A three-dimensional schematic diagram of a calibration tool for a temperature sensor in a liquid helium temperature zone provided according to an embodiment of the present invention is shown;

[0042] Figure 2 A schematic plan view of a calibration tool for a temperature sensor in a liquid helium temperature zone provided according to an embodiment of the present invention is shown;

[0043] Figure 3 Shows Figure 1 A three-dimensional schematic diagram of the cooling plate of the calibration tooling;

[0044] Figure 4 Shows Figure 3 Top view of the middle cooling plate;

[0045] Figure 5 Shows Figure 3 The front view of the middle cooling plate;

[0046] Figure 6 Shows Figure 1 A three-dimensional schematic diagram of the thermal conductive column in the calibration tooling;

[0047] Figure 7 Shows Figure 1 A three-dimensional schematic diagram of the connecting rod of the calibration tooling;

[0048] Figure 8 Shows Figure 1 3D schematic diagram of the bellows and tie rods of the calibration fixture;

[0049] Fig. 9 Shows Figure 8 Front view of the middle bellows and tie rod;

[0050] Fig.10 Shows Figure 1 Assembly diagram of the calibration tooling;

[0051] Fig.11 Shows Figure 1 Assembly diagram of the calibration tooling;

[0052] Fig.12 Shows Fig.10 The schematic diagram of the assembly of the temperature sensor and the cooling plate in the assembly drawing;

[0053] Fig.13 Shows Fig.10 The assembly diagram of the cold conduction plate and the cold end of the refrigeration device in the assembly diagram;

[0054] Fig.14 Shows Fig.10 The schematic diagram of the assembly of the bellows and the test dewar in the middle assembly diagram;

[0055] Fig.15 A flow chart of a calibration method for a calibration tool for a temperature sensor in a liquid helium temperature zone provided according to an embodiment of the present invention is shown;

[0056] Fig.16 Shows Fig.10 The middle assembly diagram is a schematic diagram of the assembly of the cooling plate in the cooling stage;

[0057] Fig.17 Shows Fig.10 The middle assembly diagram shows the bellows assembly diagram during the cooling stage;

[0058] Fig.18 Shows Fig.10 The middle assembly diagram is a schematic diagram of the cold plate assembly during the rewarming stage;

[0059] Fig.19 Shows Fig.10 The assembly drawing in the figure is a schematic diagram of the bellows assembly during the rewarming stage.

[0060] The above drawings include the following reference numerals:

[0061] 1. Cold conduction plate; 2. Heat conduction column; 3. Connecting rod; 4. Bellows; 5. Pull rod; 6. Refrigeration device; 7. Dewar. DETAILED DESCRIPTION

[0062] It should be noted that, in the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0063] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0064] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, numerical expressions and numerical values ​​do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be regarded as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0065] like Figure 1 and Figure 2 As shown, the present invention provides a calibration tool for a temperature sensor in a liquid helium temperature zone, the tool comprising a cold plate 1, a heat conducting column 2, a connecting rod 3 arranged inside a dewar 7, a bellows 4 and a pull rod 5 arranged outside the dewar 7;

[0066] The cold conduction plate 1 is provided with a plurality of mounting holes for placing the temperature sensor. The cold conduction plate 1 is used to conduct the coldness of the refrigeration device 6 to the temperature sensor in the cooling stage, and is also used to conduct the heat of the heat conduction column 2 to the temperature sensor in the heating and reheating stage;

[0067] One end of the heat-conducting column 2 is connected to one end of the cold-conducting plate 1, and the other end is connected to one end of the connecting rod 3. The heat-conducting column 2 is self-heated by a heating device;

[0068] One end of the bellows 4 is sealed and connected to the bottom of the Dewar 7;

[0069] One end of the pull rod 5 is inserted into the Dewar 7 and connected to the other end of the connecting rod 3. The middle part of the pull rod 5 is sealed and connected to the other end of the bellows 4. The pull rod 5 is pulled in a direction away from the cold end of the refrigeration device 6 to drive the bellows 4 to extend, and at the same time drive the connecting rod 3, the heat conductive column 2, the cold conduction plate 1 and the pull rod 5 to move in the same direction, so that the cold conduction plate 1 is separated from the cold end of the refrigeration device 6, thereby realizing the transition from the calibrated refrigeration stage to the natural rewarming stage.

[0070] The present invention is designed by the connection relationship of the cold plate 1, the heat conducting column 2, the connecting rod 3, the bellows 4 and the pull rod 5, so that the calibration tooling has different connection structure forms in the refrigeration stage and the rewarming stage, and has different rewarming heat sources. On the one hand, the refrigeration device 6 and the cold plate 1 are separated in the low-temperature natural rewarming process, the heat leakage of the refrigeration device 6 is isolated, the rewarming speed of the cold plate 1 is reduced, and the temperature distribution uniformity of the calibration tooling and the calibration accuracy of the sensor in the low temperature zone are improved; on the other hand, a small heat input is provided by the connecting rod 3 in the low-temperature natural rewarming stage, and a large heat input is provided by the heating device and the heat conducting column 2 in the high-temperature heating rewarming stage, which stabilizes the sensor calibration rewarming process and improves the sensor calibration efficiency; on the other hand, the temperature sensor is embedded in the cold plate 1, so that the sensor and the calibration tooling are fully contacted, and the sensor has good heat conduction efficiency, which improves the sensor calibration accuracy. The present invention is suitable for calibrating temperature sensors in the low-temperature liquid helium temperature zone (4K temperature zone), and solves the problems of low sensor calibration accuracy, low and unstable calibration process efficiency, and low heat conduction efficiency between the sensor and the tooling.

[0071] According to an embodiment of the present invention, Figure 3-Figure 5 As shown, the cooling plate 1 is in the shape of a flat cylinder.

[0072] Specifically, in order to match the cold end of the connected refrigeration device 6 and fully contact and receive cold, the diameter of the cold conduction plate 1 ranges from 65 mm to 70 mm.

[0073] In addition, in order to achieve a better cooling effect and facilitate processing, the thickness of the cooling plate 1 is 3 to 4 times the outer diameter of the temperature sensor placed in the mounting hole, and the thickness of the cooling plate 1 can generally be selected to be in the range of 9 mm to 12 mm. In order to further improve the cooling effect of the cooling plate 1, the material of the cooling plate 1 can be made of copper or oxygen-free copper, which has excellent cooling performance.

[0074] According to an embodiment of the present invention, a plurality of the mounting holes are evenly arranged on the outer wall of the flat cylinder along the circumferential direction.

[0075] Specifically, in order to avoid too many mounting holes affecting the cooling performance of the cooling plate 1, the number of mounting holes is generally 4 to 8. Among them, one standard temperature sensor and 3 to 7 temperature sensors to be calibrated are installed in the mounting holes.

[0076] In addition, in order to facilitate installation and positioning, the diameter of each mounting hole is about 10% larger than the calibrated sensor diameter. Generally, the diameter range of the mounting hole is 2 to 3 mm.

[0077] According to an embodiment of the present invention, the heating device adopts a flexible heating sheet, which is located in the Dewar 7 and wrapped around the outer wall of the heat-conducting column 2 (not shown in the figure).

[0078] Specifically, in the high-temperature heating and reheating stage, the heating device heats the heat-conducting column 2 to provide heat for the cold-conducting plate 1 .

[0079] According to an embodiment of the present invention, Figure 6 As shown, the diameter of the heat-conducting column 2 is the same as the diameter of the connecting rod 3, and the height of the heat-conducting column 2 is the same as the width of the flexible heating sheet.

[0080] Specifically, in order to ensure the heat transfer effect of the heat-conducting column 2, the diameter of the heat-conducting column 2 is in the range of 3 to 4 mm. In order to prevent the heat-conducting column 2 from being too long and causing increased heat leakage of the cold plate 1, the height of the heat-conducting column 2 is in the range of 10 to 20 mm.

[0081] In addition, in order to improve the heat conduction effect of the heat conduction column 2, the material of the heat conduction column 2 can be made of copper, oxygen-free copper or other materials with excellent heat conduction performance.

[0082] Furthermore, one end of the heat-conducting column 2 is fixedly connected to the center position of the cold-conducting plate 1 by screwing or bonding, and the other end is fixedly connected to the connecting rod 3 by screwing or bonding.

[0083] According to an embodiment of the present invention, the refrigeration device 6 adopts a refrigerator, and the cold end of the refrigerator is located in the dewar 7 to provide cold air for the cold conduction plate 1 during the refrigeration stage.

[0084] According to an embodiment of the present invention, Figure 7 As shown, the connecting rod 3 is a composite material rod.

[0085] According to one embodiment of the present invention, in order for the composite rod to provide the lowest heat input for the cold plate 1 during the low-temperature natural rewarming stage, the material of the composite rod may be low thermal conductivity materials such as glass fiber or carbon fiber; at the same time, the composite rod needs to have a smaller diameter and a larger length. Generally, the diameter of the composite rod is in the range of 3 to 4 mm and the length is more than 300 mm.

[0086] Specifically, the composite rod is fixedly connected to the pull rod 5 by screwing or bonding.

[0087] According to an embodiment of the present invention, Figure 8-Figure 9 As shown, in order to facilitate welding, the material of the bellows 4 is the same as that of the Dewar 7.

[0088] Specifically, the material of the bellows 4 can be stainless steel.

[0089] The telescopic performance of the bellows 4 can ensure that the composite rod has the ability to move the cooling plate 1 without destroying the sealing effect of the Dewar 7.

[0090] In addition, the diameter of the bellows 4 is larger than the composite rod, and generally adopts a standard part of 20 to 25 mm. The length of the bellows 4 ranges from 100 mm to 150 mm to ensure a telescopic amount of 20 to 30 mm.

[0091] like Figure 10-11 As shown in the figure, it is the overall assembly diagram of the calibration tooling during use. Before calibration, the calibration tooling is assembled first, which includes the following steps:

[0092] S1. Fix a standard temperature sensor and a plurality of temperature sensors to be calibrated in the plurality of mounting holes of the cold conducting plate 1 through thermal conductive silicone grease. Fig.12 As shown, the contact area between the temperature sensor and the cold conducting plate 1 is increased, thereby improving the heat conduction efficiency;

[0093] S2. The cold surface of the cold conduction plate 1 is brought into contact with the cold end of the refrigerator, and low-temperature thermal conductive silicone grease is used to ensure that the two surfaces are in full contact, thereby achieving a good cooling effect. Fig.13 As shown;

[0094] S3, the lower end of the bellows 4 is sealed and welded to the bottom of the Dewar 7, as shown in FIG. Fig.14 As shown, the assembly of the calibration tooling is completed.

[0095] like Fig.15 As shown, the present invention also provides a calibration method for a calibration tool for a temperature sensor in a liquid helium temperature zone, wherein the method uses any of the above-mentioned tools for calibration, and the method comprises:

[0096] S1, installing a standard temperature sensor and a plurality of temperature sensors to be calibrated in the mounting holes of the cooling plate 1;

[0097] S2. When the cold conducting plate 1 is in contact with the cold end of the refrigeration device 6, Fig.16 As shown, at this time, the bellows 4 is in a compressed state, as shown in FIG. Fig.17 As shown, the cooling plate 1 is cooled to a preset temperature by the refrigeration device 6 so that all temperature sensors in the cooling plate 1 are at a preset temperature;

[0098] S3, pull the pull rod 5 in the direction away from the cold end of the refrigeration device 6 to drive the bellows 4 to extend. At this time, the bellows 4 is in a stretched state, such as Fig.18 As shown, the cold conducting plate 1 is separated from the cold end of the refrigeration device 6, as shown in FIG. Fig.19 As shown, so that the calibration tooling is in the natural rewarming stage;

[0099] S4. When the calibration tool is in the natural rewarming stage, multiple temperature sensors to be calibrated are calibrated by a standard temperature sensor to obtain temperature calibration curves of multiple temperature sensors to be calibrated in the natural rewarming stage; wherein, in the natural rewarming stage, the calibration tool is connected to the outside only by a composite rod, and the composite rod has extremely small heat transfer, so that the cold conduction plate 1 of the calibration tool has low heat leakage and slow rewarming. This state ensures that the overall temperature of the calibration tool is uniform and improves the calibration accuracy;

[0100] S5, heating the cold conduction plate 1 by a heating device so that the calibration tooling is in a heating and re-warming stage;

[0101] S6. When the calibration tool is in the heating and reheating stage, calibrate multiple temperature sensors to be calibrated by using a standard temperature sensor to obtain temperature calibration curves of the multiple temperature sensors to be calibrated in the heating and reheating stage;

[0102] S7. Obtaining temperature calibration curves of the multiple temperature sensors to be calibrated in the full temperature range based on the temperature calibration curves of the multiple temperature sensors to be calibrated in the natural rewarming stage and the temperature calibration curves of the multiple temperature sensors to be calibrated in the heating rewarming stage.

[0103] According to an embodiment of the present invention, in S2 of the present invention, the preset temperature ranges from 1.4 to 4K.

[0104] According to an embodiment of the present invention, when the rewarming temperature in the natural rewarming stage is between 30K and 77K and the rewarming rate is less than a preset value, the heating device is turned on to enter the heating rewarming stage. At this time, the heating device conducts heat to the cold plate 1 through the heat conducting column 2, thereby improving the heat leakage and rewarming acceleration of the cold plate 1, thereby making the calibration process uniform and stable, and improving the calibration efficiency of the sensor.

[0105] According to an embodiment of the present invention, in S4 of the present invention, calibrating multiple temperature sensors to be calibrated by a standard temperature sensor to obtain temperature calibration curves of the multiple temperature sensors to be calibrated in the natural rewarming stage includes:

[0106] S41, obtaining the resistance values ​​of multiple temperature sensors to be calibrated and the temperature value of the standard temperature sensor at the current moment at every preset time interval or when the standard sensor rises to a preset temperature;

[0107] S42, obtaining temperature calibration curves of multiple temperature sensors to be calibrated in a natural rewarming stage based on the one-to-one corresponding resistance values ​​and temperature values ​​at each moment.

[0108] According to an embodiment of the present invention, in S6 of the present invention, calibrating multiple temperature sensors to be calibrated by a standard temperature sensor to obtain temperature calibration curves of the multiple temperature sensors to be calibrated in the heating and reheating stage includes:

[0109] S61, obtaining the resistance values ​​of multiple temperature sensors to be calibrated and the temperature value of the standard temperature sensor at the current moment at every preset time interval or when the standard sensor rises to a preset temperature;

[0110] S62, obtaining temperature calibration curves of multiple temperature sensors to be calibrated in the heating and reheating stage based on the one-to-one corresponding resistance values ​​and temperature values ​​at each moment.

[0111] In summary, the present invention provides a calibration tool and a calibration method for a temperature sensor in a liquid helium temperature zone. Through the design of the connection relationship between the cold plate 1, the heat conducting column 2, the connecting rod 3, the bellows 4 and the pull rod 5, the calibration tool has different connection structures in the refrigeration stage and the rewarming stage, and has different rewarming heat sources. On the one hand, the refrigeration device 6 and the cold plate 1 are separated in the low-temperature natural rewarming process, the heat leakage of the refrigeration device 6 is isolated, the rewarming speed of the cold plate 1 is reduced, and the temperature distribution uniformity of the calibration tool and the calibration accuracy of the sensor in the low-temperature zone are improved; on the other hand, a small heat input is provided by the connecting rod 3 in the low-temperature natural rewarming stage, and a large heat input is provided by the heating device and the heat conducting column 2 in the high-temperature heating rewarming stage, which stabilizes the sensor calibration rewarming process and improves the sensor calibration efficiency; on the other hand, the temperature sensor is embedded in the cold plate 1, so that the sensor and the calibration tool are fully in contact, with good heat conduction efficiency, and the sensor calibration accuracy is improved. The present invention is suitable for calibrating temperature sensors in the cryogenic liquid helium temperature zone (4K temperature zone), and solves the problems of low sensor calibration accuracy, low and unstable calibration process efficiency, and low heat conduction efficiency between the sensor and tooling.

[0112] Parts of the present invention that are not described in detail are well known to those skilled in the art.

[0113] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the devices or elements referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention. The directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0114] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0115] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0116] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A calibration tool for temperature sensors in the liquid helium temperature zone, It is characterized in that The tooling includes a cold plate, a heat-conducting column, and a connecting rod arranged inside the dewar, and a bellows and a pull rod arranged outside the dewar; The cold conduction plate is provided with a plurality of mounting holes for placing the temperature sensor, and the cold conduction plate is used to conduct the cold of the refrigeration device to the temperature sensor in the refrigeration stage, and is also used to conduct the heat of the heat conduction column to the temperature sensor in the heating and reheating stage; One end of the heat-conducting column is connected to one end of the cold-conducting plate, and the other end is connected to one end of the connecting rod, and the heat-conducting column is self-heated by a heating device; One end of the bellows is sealed and connected to the bottom of the Dewar; One end of the pull rod is inserted into the Dewar and connected to the other end of the connecting rod. The middle part of the pull rod is sealed and connected to the other end of the bellows. The pull rod is pulled in a direction away from the cold end of the refrigeration device to drive the bellows to extend, and at the same time drive the connecting rod, the heat conduction column, the cold conduction plate and the pull rod to move in the same direction, so that the cold conduction plate is separated from the cold end of the refrigeration device, thereby achieving the transition from the calibrated refrigeration stage to the natural rewarming stage.

2. The tooling according to claim 1, It is characterized in that The cooling plate is in the shape of a flat cylinder.

3. The tooling according to claim 1 or 2, It is characterized in that A plurality of mounting holes are evenly arranged on the outer wall of the flat cylinder along the circumferential direction.

4. The tooling according to claim 1, It is characterized in that The heating device adopts a flexible heating sheet, which is located in the Dewar and wrapped around the outer wall of the heat-conducting column.

5. The tooling according to claim 4, It is characterized in that The diameter of the heat-conducting column is the same as the diameter of the connecting rod, and the height of the heat-conducting column is the same as the width of the flexible heating sheet.

6. The tooling according to claim 1, It is characterized in that The refrigeration device adopts a refrigerator, the cold end of which is located in the dewar, and provides cold energy for the cold conduction plate during the refrigeration stage.

7. The tooling according to claim 1, It is characterized in that The connecting rod is a composite material rod.

8. The tooling according to claim 1, It is characterized in that The composite rod is made of glass fiber or carbon fiber.

9. The tooling according to claim 1, It is characterized in that The material of the bellows is the same as that of the Dewar.

10. A calibration method for a calibration tool for a temperature sensor in a liquid helium temperature zone, It is characterized in that The method uses any tool described in claims 1 to 9 for calibration, and the method comprises: Install a standard temperature sensor and a plurality of temperature sensors to be calibrated in the mounting holes of the cold conduction plate; When the cold conducting plate is in contact with the cold end of the refrigeration device, the cold conducting plate is cooled to a preset temperature by the refrigeration device so that all temperature sensors in the cold conducting plate are at the preset temperature; Pull the pull rod in a direction away from the cold end of the refrigeration device to extend the bellows, thereby separating the cold conduction plate from the cold end of the refrigeration device, so that the calibration tooling is in a natural rewarming stage; When the calibration tool is in the natural rewarming stage, a plurality of temperature sensors to be calibrated are calibrated by a standard temperature sensor to obtain temperature calibration curves of the plurality of temperature sensors to be calibrated in the natural rewarming stage; The cold conduction plate is heated by a heating device so that the calibration tooling is in a heating and re-warming stage; When the calibration tool is in the heating and reheating stage, a plurality of temperature sensors to be calibrated are calibrated by a standard temperature sensor to obtain temperature calibration curves of the plurality of temperature sensors to be calibrated in the heating and reheating stage; Based on the temperature calibration curves of the multiple temperature sensors to be calibrated in the natural rewarming stage and the temperature calibration curves of the multiple temperature sensors to be calibrated in the heating rewarming stage, the temperature calibration curves of the multiple temperature sensors to be calibrated in the full temperature range are obtained.

11. The method according to claim 10, It is characterized in that The preset temperature ranges from 1.4 to 4K.

12. The method according to claim 10, It is characterized in that When the rewarming temperature in the natural rewarming stage is between 30K and 77K and the rewarming rate is less than a preset value, the heating device is turned on.

13. The method according to claim 10, It is characterized in that The multiple temperature sensors to be calibrated are calibrated by using a standard temperature sensor, and the temperature calibration curves of the multiple temperature sensors to be calibrated in the natural rewarming stage are obtained, including: At every preset time interval or when the standard sensor rises to a preset temperature, the resistance values ​​of the multiple temperature sensors to be calibrated and the temperature value of the standard temperature sensor at the current moment are obtained; Based on the one-to-one corresponding resistance values ​​and temperature values ​​at each moment, temperature calibration curves of multiple temperature sensors to be calibrated in the natural rewarming stage are obtained.

14. The method according to claim 10, It is characterized in that The multiple temperature sensors to be calibrated are calibrated by using a standard temperature sensor, and the temperature calibration curves of the multiple temperature sensors to be calibrated in the heating and reheating stage are obtained, including: At every preset time interval or when the standard sensor rises to a preset temperature, the resistance values ​​of the multiple temperature sensors to be calibrated and the temperature value of the standard temperature sensor at the current moment are obtained; Based on the one-to-one corresponding resistance values ​​and temperature values ​​at each moment, temperature calibration curves of multiple temperature sensors to be calibrated in the heating and reheating stage are obtained.

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