A thermosyphon fixed-point constant temperature calibration device

Abstract

The present invention discloses a constant temperature calibration device for heat pipe fixed points, comprising: a constant temperature bath, at least four constant temperature accommodating cavities are arranged in the constant temperature bath, mercury, water, and gallium are successively contained in three of the constant temperature accommodating cavities, and the temperature detection end of a platinum resistance thermometer is placed in the other constant temperature accommodating cavity; a temperature adjusting device, which is used to adjust the temperature of the constant temperature bath. This constant temperature calibration device for heat pipe fixed points uses the melting points of three substances, mercury, water, and gallium, to calibrate the platinum resistance thermometer. Placing the three substances, mercury, water, and gallium, in the same constant temperature bath ensures the unity of temperature. Subsequently, the temperature in the constant temperature bath is successively increased from below -38.87°C to 29.80°C, and three electrical signal parameter values measured by the platinum resistance thermometer at the solid-liquid mixed states of mercury, water, and gallium are obtained respectively. By correspondingly marking the three electrical signals with three standard temperatures, three-point calibration of the platinum resistance thermometer can be achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of temperature calibration, and particularly relates to a heat pipe fixed-point constant temperature calibration device. Background Art

[0002] With the development of industrial and military technologies, there is an urgent need for on-site temperature measurement, and higher requirements are put forward for the measurement accuracy. Therefore, in order to promote the development of science and production, improve the measurement level of industrial high-precision temperature sensors, and ensure the accurate and reliable transmission of temperature values, it is necessary to solve the problem of industrial high-precision temperature measurement.

[0003] Just as a standard is needed for basic quantities, the scale for representing temperature with numbers is simply called a temperature scale, that is, a quantitative value is used to mark the thermometer, so that the thermometer can clearly display the accurate temperature value. The currently adopted international practical temperature scale is the ITS-90 (International Temperature Scale, 1990) international temperature scale. The ITS-90 temperature scale defines a series of solid-liquid phase equilibrium temperatures of metals and non-metal pure substances under a certain pressure as fixed-point temperatures, and these pure substances serve as fixed points.

[0004] Internationally, the temperature scale level is in the order of a few millikelvins, while the actual industrial application level is dozens or even hundreds of times worse than the temperature scale level. There is a large gap between the temperature scale level and the actual industrial and scientific research application levels. Moreover, the traditional fixed-point device is huge and complex, the quartz glass container is easily damaged, the calibration cost is high, and the calibration period of the thermometer is long. Considering application convenience and cost, it is not suitable for industrial applications. Therefore, only the relatively low-precision constant temperature bath comparison method can be used to calibrate industrial platinum resistance thermometers, but the uncertainty of the comparison method is relatively large and the operation process is very cumbersome. Summary of the Invention

[0005] The purpose of the present invention is to overcome the above technical deficiencies, provide a heat pipe fixed-point constant temperature calibration device, and solve the technical problem of large calibration errors in calibrating industrial platinum resistance thermometers by the constant temperature bath comparison method in the prior art.

[0006] To achieve the above technical purpose, the technical solution of the present invention provides a heat pipe fixed-point constant temperature calibration device, including:

[0007] A constant temperature bath, in which four constant temperature accommodation cavities are provided. Mercury, water, and gallium are successively contained in three of the constant temperature accommodation cavities, and the temperature detection end of a platinum resistance thermometer is placed in the other constant temperature accommodation cavity;

[0008] A temperature adjustment device, which is used to adjust the temperature of the constant temperature bath.

[0009] Further, a copper block is arranged in the constant temperature bath, and the four constant temperature accommodating cavities are all opened on the copper block. Three of the constant temperature accommodating cavities are arranged in a circumferential array around the other constant temperature accommodating cavity. The constant temperature accommodating cavity in the middle is used to place the temperature detection end of the platinum resistance thermometer. A stainless steel tank is arranged in each of the three constant temperature baths arranged in a circumferential array, and the three stainless steel tanks are correspondingly used to accommodate mercury, water, and gallium.

[0010] Further, a polytetrafluoroethylene layer is arranged on the inner wall of each stainless steel tank.

[0011] Further, a heat preservation cover is fixed to the upper end of the copper block. A docking groove penetrating through the upper and lower end faces is opened on the heat preservation cover, and the lower end of the docking groove is communicated with the upper end of the constant temperature accommodating cavity located in the center.

[0012] Further, the heat preservation cover is made of polytetrafluoroethylene.

[0013] Further, the temperature regulating device can regulate the temperature in the constant temperature bath within the range of -40°C to +60°C.

[0014] Further, the heat pipe fixed point constant temperature calibration device further includes a constant temperature sleeve. A liquid cavity is arranged between the inner peripheral surface and the outer peripheral surface of the constant temperature sleeve. Methyl silicone oil is contained in the liquid cavity, and the constant temperature bath is the space within the inner peripheral surface of the constant temperature sleeve.

[0015] Further, the copper block is cylindrical, the constant temperature sleeve is coaxially sleeved on the copper block, and the temperature regulating end of the temperature regulating device is placed inside the liquid cavity.

[0016] Further, the heat pipe fixed point constant temperature calibration device further includes heat preservation cotton, and the heat preservation cotton is wrapped around the outer peripheral surface of the constant temperature sleeve.

[0017] Compared with the prior art, the beneficial effects of the present invention include: The heat pipe fixed point constant temperature calibration device uses the melting points of three substances, mercury, water, and gallium, to calibrate the platinum resistance thermometer. The melting point of mercury under one standard atmosphere is -38.87°C, the melting point of water under one standard atmosphere is 0°C, and the melting point of gallium under one standard atmosphere is 29.80°C. Placing the three substances, mercury, water, and gallium, in the same constant temperature bath ensures the unity of temperature. Subsequently, the temperature in the constant temperature bath is slowly increased from below -38.87°C to 29.80°C, and three electrical signal parameter values measured by the platinum resistance thermometer when the solid-liquid mixed states of mercury, water, and gallium are obtained in sequence. Marking the three electrical signals with the three standard temperatures can achieve the three-point calibration of the platinum resistance thermometer. Description of the Drawings

[0018] Figure 1 It is a schematic structural diagram of an implementation manner of a heat pipe fixed-point constant temperature calibration device provided by the present invention. Specific Embodiment

[0019] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0020] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there can also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are only for the purpose of illustration and do not represent the only implementation manner.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0022] The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0023] Please refer to Figure 1 , this embodiment provides a heat pipe fixed-point constant temperature calibration device, including: a constant temperature bath, a temperature adjustment device 1 ( Figure 1 is a side view, Figure 1 only three constant temperature accommodation chambers are shown, including a constant temperature accommodation chamber in the middle position).

[0024] At least four constant temperature accommodation chambers are provided in the constant temperature bath. Mercury, water, and gallium are sequentially contained in three of the constant temperature accommodation chambers, and the temperature detection end of a platinum resistance thermometer is placed in the other constant temperature accommodation chamber. The temperature adjustment device is used to adjust the temperature of the constant temperature bath.

[0025] This heat pipe fixed-point constant temperature calibration device uses the melting points of three substances, mercury, water, and gallium, to calibrate a platinum resistance thermometer. The melting point of mercury at standard atmospheric pressure is -38.87 °C, the melting point of water at standard atmospheric pressure is 0 °C, and the melting point of gallium at standard atmospheric pressure is 29.80 °C. Placing the three substances, mercury, water, and gallium, in the same constant temperature bath ensures temperature uniformity. Subsequently, the temperature in the constant temperature bath is slowly raised from below -38.87 °C to 29.80 °C, and three electrical signal parameter values measured by the platinum resistance thermometer are obtained successively when mercury, water, and gallium are in their solid-liquid mixed states. Marking the three electrical signals corresponding to the three standard temperatures can achieve three-point calibration of the platinum resistance thermometer.

[0026] In this embodiment, a copper block 2 is provided in the constant temperature bath. Four constant temperature accommodating cavities are all opened on the copper block 2. Three of the constant temperature accommodating cavities are arranged in a circumferential array around the other constant temperature accommodating cavity. The constant temperature accommodating cavity in the middle is used to place the temperature detection end of the platinum resistance thermometer. A stainless steel tank 3 is provided in each of the three constant temperature accommodating cavities arranged in a circumferential array. The three stainless steel tanks 3 are respectively used to accommodate mercury, water, and gallium. And the constant temperature accommodating cavity is a vertically arranged cylindrical accommodating cavity. The four constant temperature accommodating cavities are arranged tangent to and adjacent to each other. And the outer peripheral surface of the stainless steel tank has a clearance fit with the inner peripheral surface of the constant temperature accommodating cavity, so as to ensure that the heat of the four constant temperature accommodating cavities restricts each other.

[0027] A polytetrafluoroethylene layer is provided on the inner wall of each stainless steel tank 3.

[0028] A heat preservation cover 4 is fixed to the upper end of the copper block 2. A docking groove 4a penetrating its upper and lower end faces is opened on the heat preservation cover 4. The lower end of the docking groove 4a communicates with the upper end of the constant temperature accommodating cavity located in the center. The detection end of the platinum resistance thermometer is inserted into the copper block 2 through the docking groove 4a. The heat preservation cover 4 is made of polytetrafluoroethylene.

[0029] In this embodiment, the temperature regulating device 1 can adjust the temperature in the constant temperature bath within the range of -40 °C to +60 °C. The heat pipe fixed-point constant temperature calibration device further includes a constant temperature sleeve 5. A liquid cavity 5a is provided between the inner peripheral surface and the outer peripheral surface of the constant temperature sleeve 5. Methyl silicone oil is contained in the liquid cavity 5a. The constant temperature bath is the space within the inner peripheral surface of the constant temperature sleeve 5. The copper block 2 is cylindrical. The constant temperature sleeve 5 is coaxially sleeved on the copper block 2. The temperature regulating end (such as an evaporator, a condenser) of the temperature regulating device 1 is placed inside the liquid cavity 5a. The heat pipe fixed-point constant temperature calibration device further includes heat preservation cotton, and the heat preservation cotton is wrapped around the outer peripheral surface of the constant temperature sleeve 5.

[0030] In this embodiment, the constant temperature calibration device for the heat pipe fixing points further includes three air pressure regulating devices. The regulating ends of the three air pressure regulating devices are respectively connected to the inner cavities of the three stainless steel tanks 3, and are respectively used to regulate the air pressure in the inner cavities of the three stainless steel tanks 3. It is used to keep the air pressure in the three stainless steel tanks 3 at the standard atmospheric pressure. For example, each stainless steel tank 3 is a tubular structure with an open upper end. An upper piston 6 is arranged in the upper part of the inner cavity of each stainless steel tank 3. A pressure sensor a is arranged on the lower end face of the piston 6 for real-time monitoring of the air pressure in the stainless steel tank 3. The upper end of the piston 6 is connected to a piston push rod 7. By changing the volume of the stainless steel tank 3 through the piston push rod 7, the air pressure value in the inner cavity of the stainless steel tank 3 can be controlled, avoiding the volatilization and leakage of mercury, water, and gallium, and improving the safety of the device during use. The upper end of the piston push rod 7 is fixedly connected to the output shaft of the linear servo motor, thus realizing precise control of the linear motion.

[0031] Working principle: This constant temperature calibration device for the heat pipe fixing points uses the melting points of three substances, mercury, water, and gallium, to calibrate the platinum resistance thermometer. The melting point of mercury under a standard atmospheric pressure is -38.87 °C, the melting point of water under a standard atmospheric pressure is 0 °C, and the melting point of gallium under a standard atmospheric pressure is 29.80 °C. Placing the three substances, mercury, water, and gallium, in the same constant temperature bath ensures the unity of temperature. Subsequently, the temperature in the constant temperature bath is slowly raised from below -38.87 °C to 29.80 °C, and three electrical signal parameter values measured by the platinum resistance thermometer when the solid-liquid mixed states of mercury, water, and gallium are obtained in sequence. Marking the three electrical signal parameter values corresponding to the three standard temperatures can achieve the three-point calibration of the platinum resistance thermometer.

[0032] The above specific embodiments of the present invention do not constitute a limitation to the protection scope of the present invention. Any other corresponding changes and deformations made according to the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A thermosyphon fixed-point constant temperature calibration device, characterized in that, it includes: A constant temperature bath, in which four constant temperature accommodation cavities are arranged. Mercury, water, and gallium are successively contained in three of the constant temperature accommodation cavities, and the temperature detection end of a platinum resistance thermometer is placed in the other constant temperature accommodation cavity; A temperature adjustment device, which is used to adjust the temperature of the constant temperature bath; A copper block is arranged in the constant temperature bath. Four constant temperature accommodation cavities are all opened on the copper block. Three of the constant temperature accommodation cavities are arranged in a circumferential array around the other constant temperature accommodation cavity. The constant temperature accommodation cavity in the middle is used to place the temperature detection end of the platinum resistance thermometer. A stainless steel tank is arranged in each of the three constant temperature baths arranged in a circumferential array. The three stainless steel tanks are correspondingly used to contain mercury, water, and gallium; Three air pressure adjustment devices, the adjustment ends of the three air pressure adjustment devices are correspondingly connected to the inner cavities of the three stainless steel tanks. Each air pressure adjustment device includes a piston, an air pressure sensor, and a piston push rod. The piston is arranged in the upper part of the inner cavity of the stainless steel tank. The air pressure sensor is arranged on the lower end face of the piston. The piston push rod is connected to the upper end of the piston. By changing the volume of the stainless steel tank, the air pressure in the three stainless steel tanks is maintained at the standard atmospheric pressure.

2. The thermosyphon fixed-point constant temperature calibration device according to claim 1, characterized in that, A polytetrafluoroethylene layer is arranged on the inner wall of each stainless steel tank.

3. The thermosyphon fixed-point constant temperature calibration device according to claim 2, characterized in that, A heat preservation cover is fixed on the upper end of the copper block. A docking groove penetrating through its upper and lower end faces is opened on the heat preservation cover. The lower end of the docking groove is communicated with the upper end of the constant temperature accommodation cavity located in the center.

4. The thermosyphon fixed-point constant temperature calibration device according to claim 3, characterized in that, The heat preservation cover is made of polytetrafluoroethylene.

5. The thermosyphon fixed-point constant temperature calibration device according to claim 1, characterized in that, The temperature adjustment device can adjust the temperature in the constant temperature bath within the range of -40°C to +60°C.

6. The thermosyphon fixed-point constant temperature calibration device according to claim 4, characterized in that, The thermosyphon fixed-point constant temperature calibration device further includes a constant temperature sleeve. A liquid cavity is arranged between the inner peripheral surface and the outer peripheral surface of the constant temperature sleeve. Methyl silicone oil is contained in the liquid cavity. The constant temperature bath is the space within the inner peripheral surface of the constant temperature sleeve.

7. The thermosyphon fixed-point constant temperature calibration device according to claim 6, characterized in that, The copper block is cylindrical. The constant temperature sleeve is coaxially sleeved on the copper block. The temperature adjustment end of the temperature adjustment device is placed in the liquid cavity.

8. The thermosyphon fixed-point constant temperature calibration device according to claim 6, characterized in that, The thermosyphon fixed-point constant temperature calibration device further includes heat preservation cotton, and the heat preservation cotton is wrapped around the outer peripheral surface of the constant temperature sleeve.

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