CN115342945A - Testing device and method for evaluating installation mode of temperature sensor under vacuum low temperature - Google Patents
Testing device and method for evaluating installation mode of temperature sensor under vacuum low temperature Download PDFInfo
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- CN115342945A CN115342945A CN202210913996.XA CN202210913996A CN115342945A CN 115342945 A CN115342945 A CN 115342945A CN 202210913996 A CN202210913996 A CN 202210913996A CN 115342945 A CN115342945 A CN 115342945A
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Abstract
The invention relates to a testing device and a method for evaluating the installation mode of a temperature sensor under vacuum low temperature, belonging to the technical field of low-temperature engineering research and development application. The device comprises a control valve A, a vacuum valve, a control valve B, a pressure transmitter, a vacuumizing device, a liquid level meter, a computer, a vacuum electric connector, a vacuum box, a heat insulation layer, a low-temperature container and a calibration temperature sensor. The method adopts the device, uses a computer to continuously collect and analyze the data of the calibrated temperature sensor and the temperature sensor to be evaluated, and compares and judges the obtained data, thus evaluating the installation mode of the temperature sensor under vacuum and low temperature. According to the device and the method, the sensitivity and the precision of the temperature sensor to be evaluated are directly compared with those of the calibration temperature sensor, so that the measurement accuracy is high; a plurality of temperature sensors mounted in different mounting manners can be measured and evaluated at the same time.
Description
Technical Field
The invention relates to a testing device and a method for evaluating the installation mode of a temperature sensor under vacuum low temperature, belonging to the technical field of low-temperature engineering research and development application.
Background
How to install the temperature sensor in a vacuum low-temperature environment to improve the sensitivity and accuracy of the measurement thereof has been a great problem in the industry.
The installation modes of the temperature sensor in the existing vacuum low-temperature environment mainly include the following four modes:
(1) the temperature sensor is directly pasted on the tested piece by using low-temperature heat-sensitive glue. The advantages of this mounting method are: the operation is simple, and the cost is low; the disadvantages are that: the requirement on the performance of the low-temperature thermal sensitive adhesive is high, but the service life is short, and the repair risk frequency is high.
(2) The tool is fixed on a tested piece in a welding mode, and then the temperature sensor is pasted on the tool by using low-temperature thermosensitive adhesive. The advantages of this mounting method are: the economy is better, the operation is simpler; the disadvantages are that: the temperature of the tested piece is conducted to the low-temperature thermal sensitive adhesive through the tool and then is conducted to the temperature sensor, and the temperature deviation is larger than that of the installation mode (1).
(3) And punching a hole on the tested piece, punching the temperature sensor into the hole, and sealing by adopting a welding mode and the like. The advantages of this mounting method are: the temperature measurement accuracy is high; the disadvantages are that: there is a risk of leakage of the medium in the test piece.
(4) The lead of the temperature sensor is wound around the tested piece or the pipeline device for several circles and then connected to the temperature sensor (i.e. the 'heat sink' is made first), and the installation mode can be any one of the installation modes (1), (2) or (3). The advantages of this mounting method are: the temperature measurement is accurate; the disadvantages are that: the cost is high.
Since the mounting methods each have advantages and disadvantages, a test device capable of evaluating the accuracy, sensitivity, and economy of the mounting method of the low-temperature sensor in a vacuum environment is required.
Disclosure of Invention
In order to overcome the defects in the prior art, the invention aims to provide a testing device and a method for evaluating the mounting mode of a temperature sensor under vacuum and low temperature. The device and the method can evaluate the accuracy, the sensitivity and the economy of the installation mode of the low-temperature sensor in the vacuum environment; the device has the advantages of high measurement accuracy, repeated use, low manufacturing difficulty, controllable cost and convenient disassembly and maintenance.
In order to achieve the purpose of the invention, the following technical scheme is provided.
A testing device for evaluating the installation mode of a temperature sensor under vacuum low temperature comprises a control valve A, a vacuum valve, a control valve B, a pressure transmitter, a vacuumizing device, a liquid level meter, a computer, a vacuum electric connector, a vacuum box, a heat-insulating layer, a low-temperature container and a calibration temperature sensor.
The low-temperature container is a container with an opening at the upper end and is used for containing low-temperature liquid as a tested piece. The low-temperature container is positioned in the vacuum box.
The vacuum box mainly comprises a box body and a top cover, a detachable sealing connection structure is arranged between the top cover and the box body, a flange structure is preferably adopted, and a sealing structure such as a fluororubber sealing ring, a nitrile rubber sealing ring or a polytetrafluoroethylene gasket is arranged at the joint. The vacuum box is used for providing a vacuum environment.
The inner wall of the vacuum box is coated with a heat insulation material to form a heat insulation layer for keeping the low-temperature test environment of the tested piece. The heat-insulating layer has apparent heat conductivity coefficient less than or equal to 1.5 × 10 -4 W/(m.K), air release rate less than or equal to 8 x 10 -7 Pa·m 3 /(s · g) insulating materials such as Fuji low temperature insulating paper/transmission screen composite products PL-900-5, ZL-1110-2, etc.
Preferably, a radiation-proof screen is further arranged below the top cover in the vacuum box, the radiation-proof screen is a stainless steel 304 or 316L material mirror steel plate with the thickness of less than or equal to 2mm, the shape of the radiation-proof screen is similar to the shape of the cross section of the vacuum box and is slightly smaller than the cross section of the vacuum box, when the cross section of the vacuum box is circular, the shape of the radiation-proof screen is preferably circular, and the diameter of the radiation-proof screen is 10 mm-20 mm smaller than the inner diameter of the vacuum box. The radiation protection screen is arranged on the upper part of the low-temperature container after being connected with the top cover through a fixed connecting piece, the heat conductivity of the fixed connecting piece is less than or equal to 1.0W/(m.K), and preferably, the fixed connecting piece is a glass fiber reinforced plastic bolt. The radiation-proof screen is used for reducing heat exchange between a tested piece and the external environment temperature in the device so as to provide a better and more stable low-temperature testing environment.
The control valve A is positioned outside the vacuum box, is arranged on the low-temperature liquid conveying pipeline and is used for controlling the input of the low-temperature liquid. One end of the low-temperature liquid conveying pipeline is positioned outside the vacuum box and communicated with the low-temperature liquid, and the other end of the low-temperature liquid conveying pipeline extends into the low-temperature container through a top cover of the vacuum box.
The vacuum-pumping device and the vacuum valve are positioned outside the vacuum box, and the vacuum valve is arranged on the vacuum-pumping pipeline. One end of the vacuum pumping pipeline is positioned outside the vacuum box and is connected with the vacuum pumping device, and the other end of the vacuum pumping pipeline extends into the vacuum box through the top cover of the vacuum box and is positioned outside the low-temperature liquid in the low-temperature container.
Since the low-temperature liquid is gasified to generate gas, the vacuum chamber is a sealed container, and therefore, the gas needs to be discharged. And the control valve B is positioned outside the vacuum box, is arranged on the gas output pipeline and is used for controlling the output of gas. One end of the gas output pipeline is positioned outside the vacuum box, and the other end of the gas output pipeline extends into the vacuum box through the top cover of the vacuum box and is positioned outside the low-temperature liquid in the low-temperature container.
Preferably, when the gas needs to be recycled, such as toxic gas or gas with recycling value, the gas output pipeline is connected with a gas recycling device at one end outside the vacuum box.
The pressure transmitter is positioned outside the vacuum box and is connected with one end of the gas pressure testing pipeline, and the other end of the gas pressure testing pipeline extends into the vacuum box through the top cover of the vacuum box and is positioned outside the low-temperature liquid of the low-temperature container and used for testing the gas pressure formed by the gasified gas of the low-temperature liquid in the closed vacuum box. When the pressure transmitter detects that the gas pressure is lower than 10Pa, the control valve B is opened to discharge the gas.
Since the amount of cryogenic liquid added cannot exceed the volume of the cryogenic vessel, a level gauge is provided for measuring the level change of cryogenic liquid in the cryogenic vessel to control the opening and closing of valve a. Preferably, when the liquid level of the low-temperature liquid reaches 1/2-2/3 of the volume of the low-temperature container, the control valve A is closed, and the low-temperature liquid is stopped to be input. The liquid level meter can be a liquid level meter which meets the use requirement in the prior art, such as a differential pressure liquid level meter or a laser liquid level meter. In the process of injecting the low-temperature liquid into the low-temperature container, the low-temperature liquid is in a continuous vaporization process all the time, the liquid level fluctuation is large, and the measurement precision of the laser liquid level meter is lower than that of a differential pressure liquid level meter, so the liquid level meter is preferably a differential pressure liquid level meter.
When the liquid level meter is used for differential pressure liquid level timing, the differential pressure liquid level meter device is positioned outside the vacuum box and is connected with two liquid pressure testing pipelines, one liquid pressure testing pipeline extends into the vacuum box through the top cover of the vacuum box and is positioned above the liquid level of the low-temperature liquid of the low-temperature container, and the other liquid pressure testing pipeline extends into the vacuum box through the top cover of the vacuum box and extends into the low-temperature container from the bottom of the low-temperature container.
The control valve A and the control valve B are both stop valves or switch valves with good sealing performance, and can be pneumatic valves, manual valves or automatic control valves, such as ball valves.
The low-temperature liquid conveying pipeline, the vacuumizing pipeline, the gas output pipeline, the gas pressure testing pipeline and the liquid pressure testing pipeline are respectively and independently in sealing connection with the top cover of the vacuum box, and a welded sealing connection form can be adopted.
The calibration temperature sensor is an immersion temperature sensor, is directly immersed in the low-temperature liquid of the low-temperature container when in use, and is calibrated before installation to ensure the reading correctness.
The top cover of the vacuum box is provided with a vacuum electric connector which is used for leading a sensor wire of a calibration temperature sensor positioned in the vacuum box to penetrate out of the vacuum box and be connected with the vacuum box in a sealing way; and the sensor lead penetrates out of the vacuum box and then is connected to a computer.
The material of the low-temperature container is preferably stainless steel. After the low-temperature liquid is input into the low-temperature container, the temperature stabilization time of the low-temperature container is related to the material used by the low-temperature container, when the material of the low-temperature container is stainless steel, the preferred stabilization time is 30 minutes, the data curve measured by a computer at the moment tends to be a straight line, and the temperature fluctuation range is not more than 1K.
Preferably, the cryogenic liquid is liquid hydrogen, liquid oxygen, liquid nitrogen, liquid helium or liquefied natural gas.
Installing a temperature sensor to be evaluated on the low-temperature container, wherein a sensor lead of the temperature sensor to be evaluated penetrates out of the vacuum box and is connected with the vacuum box in a sealing manner; and the sensor lead penetrates out of the vacuum box and then is connected to a computer. The installation mode can adopt the installation mode of the temperature sensor in the existing vacuum low-temperature environment. The number of the temperature sensors to be evaluated is more than one, and when the number of the temperature sensors is more than two, the same installation mode or different installation modes can be adopted.
The computer is positioned outside the vacuum box and used for calibrating the temperature sensor and continuously collecting and analyzing data of the temperature sensor to be evaluated, and collecting data from the time that low-temperature liquid is injected into the low-temperature container to the time that the temperature of the low-temperature container is stable, the temperature stability mark is that a data curve measured by the computer tends to be close to a straight line, and the temperature fluctuation range is not more than 1K.
The invention discloses a method for evaluating the installation mode of a temperature sensor under vacuum low temperature, which is carried out by adopting the device provided by the invention and comprises the following specific steps:
after the device components and the temperature sensor to be evaluated are installed, the control valve A, the vacuum valve, the control valve B, the pressure transmitter and the vacuum pumping device are all in a closed state, and the box body of the vacuum box is in sealing connection with the top cover.
When the test is started, starting the vacuumizing device, opening the vacuum valve, vacuumizing the vacuum box to below 10Pa, and closing the vacuum valve and the vacuumizing device; opening the control valve A and the pressure transmitter, injecting low-temperature liquid into the low-temperature container, gasifying the low-temperature liquid to generate gas, opening the control valve B when the pressure transmitter detects that the air pressure in the closed vacuum box reaches below 10Pa, discharging the gas to the external environment of the vacuum box through a pipeline, and preferably discharging the gas to a gas recovery device when the gas needs to be recovered.
Injecting low-temperature liquid into the low-temperature container until a liquid level meter displays that the low-temperature liquid reaches a specified liquid level, and preferably, the specified liquid level is 1/2-2/3 of the volume of the low-temperature container; the control valve A is closed, and the injection of the cryogenic liquid is stopped.
Continuously acquiring and analyzing data of a calibration temperature sensor and a temperature sensor to be evaluated by a computer, acquiring data from the time when low-temperature liquid is injected into a low-temperature container until the temperature of the low-temperature container is stable, comparing the reading of the temperature sensor to be evaluated with the reading of the calibration temperature sensor, and if the time when the temperature sensor to be evaluated reaches the stability is closer to the time when the calibration temperature sensor reaches the stability, indicating that the reaction sensitivity of the temperature sensor to be evaluated is higher, wherein the installation mode has the minimum influence on the sensitivity of the temperature sensor; if the reading fluctuation of the temperature sensor to be evaluated is small and no jump occurs in the process of achieving stability, the temperature sensor is excellent in performance, the installation mode has no influence on temperature conduction, and the two conditions are met, so that the performance of the temperature sensor in the installation mode is optimal.
In the method, each component can adopt a manual control mode or an automatic control mode.
Advantageous effects
1. The invention provides a testing device and a method for evaluating the installation mode of a temperature sensor under vacuum low temperature, the device and the method can directly compare the sensitivity and the precision of the temperature sensor to be evaluated with a calibration temperature sensor, and the measurement accuracy is high.
2. The invention provides a testing device and a method for evaluating the installation mode of a temperature sensor under vacuum low temperature, which can simultaneously measure and evaluate a plurality of temperature sensors installed in different installation modes.
3. The invention provides a testing device for evaluating the installation mode of a temperature sensor under vacuum low temperature, which can be repeatedly used.
4. The invention provides a testing device for evaluating the mounting mode of a temperature sensor under vacuum low temperature, which has the advantages of simple structure, low manufacturing difficulty and controllable cost.
5. The invention provides a testing device for evaluating the installation mode of a temperature sensor under vacuum low temperature, which is convenient to disassemble and maintain.
6. The invention provides a testing device for evaluating the mounting mode of a temperature sensor under vacuum low temperature, wherein a radiation-proof screen is preferably arranged in the device and used for reducing the heat exchange between the low temperature in the device and the external environment temperature so as to provide a better and more stable low-temperature testing environment.
Drawings
Fig. 1 is a schematic structural diagram of a testing apparatus for evaluating an installation manner of a temperature sensor under vacuum and low temperature in an embodiment of the present invention.
The system comprises a control valve A, a control valve B, a control valve A, a vacuum valve B, a control valve B, a gas recovery device, a pressure transmitter, a vacuumizing device, a liquid level meter, a computer, a vacuum electric connector, a vacuum box, a heat insulation layer, a low-temperature container, a temperature sensor A, a temperature sensor B, a calibration temperature sensor, a temperature sensor C and a radiation protection screen, wherein the control valve A, the vacuum valve A, the control valve B, the vacuum gas recovery device, the pressure transmitter, the vacuumizing device, the liquid level meter, the computer, the vacuum electric connector, the vacuum box, the heat insulation layer, the low-temperature container, the temperature sensor A, the temperature sensor B, the calibration temperature sensor B, and the temperature sensor C and the radiation protection screen are arranged in sequence from 1 to 10.
Detailed Description
The invention is described in detail below with reference to the drawings and specific examples, but the invention is not limited thereto.
Example 1
A testing device for evaluating the installation mode of a temperature sensor under vacuum low temperature is shown in figure 1, and comprises a control valve A1, a vacuum valve 2, a control valve B3, a pressure transmitter 5, a vacuumizing device 6, a liquid level meter 7, a computer 8, a vacuum electric connector 9, a vacuum box 10, a heat insulation layer 11, a low-temperature container 12 and a calibration temperature sensor 15.
The low temperature container 12 is a stainless steel cylinder with an open upper end for containing liquid nitrogen. As a test piece, a cryogenic container 12 is located inside the vacuum box 10.
The vacuum box 10 mainly comprises a box body and a top cover, a detachable flange sealing connection structure is arranged between the top cover and the box body, and a fluororubber sealing ring is arranged at the connection position. The vacuum box 10 is used to provide a vacuum environment.
The inner wall of the vacuum box 10 is coated with a heat insulation material to form a heat insulation layer 11, which is used for keeping the low-temperature test environment of the tested piece. The heat-insulating layer 11 is made of Fuji low-temperature heat-insulating paper/emission screen composite product PL-900-5.
A radiation-proof screen 17 is further arranged below a top cover in the vacuum box 10, the radiation-proof screen 17 is a stainless steel 304 mirror steel plate with the thickness being smaller than or equal to 2mm, the cross section of the vacuum box 10 is circular, the radiation-proof screen 17 is a circular plate, and the diameter of the radiation-proof screen 17 is 10-20 mm smaller than the inner diameter of the vacuum box 10. The radiation-proof screen 17 is arranged on the upper part of the low-temperature container 12 after being connected with the top cover through glass fiber reinforced plastic bolts. The radiation-proof screen 17 is used for reducing the heat exchange between the tested piece in the device and the external environment temperature so as to provide a better and more stable low-temperature testing environment.
The control valve A1 adopts a Shiwecker SS-65TSW12P valve, is positioned outside the vacuum box 10, is arranged on a cryogenic liquid conveying pipeline and is used for controlling the input of cryogenic liquid. One end of the cryogenic liquid conveying pipeline is positioned outside the vacuum box 10 and is communicated with cryogenic liquid, and the other end of the cryogenic liquid conveying pipeline extends into the cryogenic container 12 through a top cover of the vacuum box 10.
The vacuum-pumping device 6 and the vacuum valve 2 are located outside the vacuum box 10, and the vacuum valve 2 is mounted on a vacuum-pumping pipeline by using a Shiviaoke LD series valve. One end of the vacuum-pumping pipeline is positioned outside the vacuum box 10 and connected with the vacuum-pumping device 6, and the other end of the vacuum-pumping pipeline extends into the vacuum box 10 through the top cover of the vacuum box 10 and is positioned above the liquid level of the low-temperature liquid in the low-temperature container 12.
Since the low-temperature liquid is gasified to generate gas, the vacuum chamber 10 is a sealed container, and therefore, the gas needs to be discharged. The control valve B3 adopts a Shiviaoke SS-65TSW12P valve, is positioned outside the vacuum box 10, is arranged on a gas output pipeline and is used for controlling the output of gas. One end of the gas output pipeline is positioned outside the vacuum box 10, and the other end of the gas output pipeline extends into the vacuum box 10 through the top cover of the vacuum box 10 and is positioned above the liquid level of the low-temperature liquid in the low-temperature container 12.
The pressure transmitter 5 is located outside the vacuum box 10 and connected with one end of a gas pressure test pipeline, and the other end of the gas pressure test pipeline extends into the vacuum box 10 through a top cover of the vacuum box 10 and is located above the liquid level of the low-temperature liquid in the low-temperature container 12 and used for testing the gas pressure formed by the gasified gas of the low-temperature liquid in the closed vacuum box 10. When the pressure of the gas measured by the pressure transmitter 5 is lower than 10Pa, the control valve B3 is opened to discharge the gas.
Since the amount of cryogenic liquid added cannot exceed the volume of the cryogenic vessel 12, a level meter 7 is provided for measuring the level change of cryogenic liquid in the cryogenic vessel 12 to control the opening and closing of the valve A1. When the liquid level of the cryogenic liquid reaches 1/2 of the volume of the cryogenic container 12, the control valve A1 is closed, and the input of the cryogenic liquid is stopped. The liquid level meter 7 is a differential pressure liquid level meter and adopts seven-star Huazhi CYQ-3051DP. The liquid level meter 7 is positioned outside the vacuum box 10 and is connected with two liquid pressure testing pipelines, one liquid pressure testing pipeline extends into the vacuum box 10 through the top cover of the vacuum box 10 and is positioned above the liquid level of the low-temperature liquid in the low-temperature container 12, and the other liquid pressure testing pipeline extends into the vacuum box 10 through the top cover of the vacuum box 10 and extends into the low-temperature container 12 from the bottom of the low-temperature container 12.
The low-temperature liquid conveying pipeline, the vacuumizing pipeline, the gas output pipeline, the gas pressure testing pipeline and the liquid pressure testing pipeline are respectively and independently connected with the top cover of the vacuum box 10 in a sealing mode through welding.
The calibration temperature sensor 15 is an immersion temperature sensor, and is immersed directly in the cryogenic liquid in the cryogenic container 12 when in use, and is calibrated before installation to ensure the reading accuracy.
A vacuum electric connector 9 is arranged on the top cover of the vacuum box 10 and is used for leading a sensor lead of a calibration temperature sensor 15 positioned in the vacuum box 10 to penetrate out of the vacuum box 10 and be hermetically connected with the vacuum box 10; the sensor leads are connected to the computer 8 after passing out of the vacuum box 10.
Installing a temperature sensor to be evaluated on the low-temperature container 12, wherein a sensor lead of the temperature sensor to be evaluated penetrates out of the vacuum box 10 and is connected with the vacuum box 10 in a sealing manner; the sensor leads are connected to the computer 8 after passing out of the vacuum box 10.
The temperature sensor to be evaluated and the calibration temperature sensor 15 are the same temperature sensor, and there are three temperature sensors in total, namely a temperature sensor a 13, a temperature sensor B14 and a temperature sensor C16.
The temperature sensor a 13 is mounted in the following manner: directly sticking the temperature sensor A13 to a tested piece by using low-temperature heat-sensitive adhesive, namely, the installation mode (1) in the prior art;
the temperature sensor B14 is mounted in the following manner: fixing the tool on a tested piece in a welding mode, and then sticking a temperature sensor B14 to the tool by using low-temperature heat-sensitive adhesive, namely, the installation mode (2) in the prior art;
the temperature sensor C16 is mounted in the following manner: punching a hole on a tested piece, punching a temperature sensor C16 into the hole, and sealing by welding, namely the installation mode (3) in the prior art;
in this embodiment, the mounting manners (1), (2) and (3) are not used as "heat sinks".
The computer 8 adopts thinpad X1, is positioned outside the vacuum box 10, is used for calibrating the continuous acquisition and analysis of data of the temperature sensor 15 and the temperature sensor to be evaluated, and acquires data from the injection of liquid nitrogen into the low-temperature container 12 until the temperature of the low-temperature container 12 is stable, wherein the stabilization time is 30 minutes, the data curve measured by the computer 8 tends to be a nearly straight line at the moment, and the temperature fluctuation range does not exceed 1K.
A method for evaluating the installation mode of a temperature sensor under vacuum low temperature is carried out by adopting the device of the embodiment, and comprises the following specific steps:
after the device components and the temperature sensor to be evaluated are installed, the control valve A1, the vacuum valve 2, the control valve B3, the pressure transmitter 5 and the vacuumizing device 6 are all in a closed state, and the box body of the vacuum box 10 is in sealing connection with the top cover.
When the test is started, starting the vacuumizing device 6, opening the vacuum valve 2, vacuumizing the vacuum box 10 to be below 10Pa, and closing the vacuum valve 2 and the vacuumizing device 6; opening the control valve A1 and the pressure transmitter 5, injecting low-temperature liquid nitrogen into the low-temperature container 12, gasifying the liquid nitrogen to generate gas, and opening the control valve B3 when the pressure transmitter 5 detects that the air pressure in the closed vacuum box 10 reaches below 10Pa, and discharging the gas to the external environment of the vacuum box 10 through a pipeline.
Injecting liquid nitrogen into the cryogenic container 12 until the liquid level meter 7 indicates that the differential pressure reaches 2/3 of the volume of the cryogenic container 12; the control valve A1 is closed and the injection of liquid nitrogen is stopped.
The data of the calibration temperature sensor 15 and the temperature sensor to be evaluated are continuously collected and analyzed by the computer 8, data from the injection of liquid nitrogen into the low-temperature container 12 until the temperature of the low-temperature container 12 is stable are collected, and the data are compared with the readings of the temperature sensor to be evaluated and the calibration temperature sensor 15.
In the method, each component can adopt a manual control mode or an automatic control mode.
The result of the comparison data shows that:
the data of the temperature sensor C16 tend to be stable more quickly, and the time is about 2 minutes longer than the time for calibrating the temperature sensor 15 to tend to be stable; the time for the temperature sensor A13 and the temperature sensor B14 to tend to be stable is equivalent to about 5 minutes longer than the time for the calibration temperature sensor 15 to tend to be stable. Therefore, the mounting system using the temperature sensor C16 is determined to have higher sensitivity.
The values of the temperature sensor A13, the temperature sensor B14 and the temperature sensor C16 after tending to be stable are equivalent to the readings of the calibrated temperature sensor 15 after tending to be stable, so that the accuracy of temperature measurement of the temperature sensors is not influenced by the mounting modes (1), (2) and (3).
Example 2
A test device for evaluating the installation mode of a temperature sensor under vacuum low temperature is shown in figure 1, wherein the installation mode of a temperature sensor A13 is as follows: firstly, making a heat sink, namely connecting the lead of the temperature sensor A13 to the temperature sensor A13 after winding the lead of the temperature sensor A13 for several circles; then, the installation mode (1) in the embodiment 1 is adopted, namely the temperature sensor A13 is directly pasted on the tested piece by using low-temperature heat-sensitive adhesive;
the temperature sensor B14 is mounted in the following manner: firstly, making a heat sink, namely winding the lead of the temperature sensor B14 around the tested piece for several circles and then connecting the lead to the temperature sensor B14; then, the installation mode (2) in the embodiment 1 is adopted, namely, the tool is fixed on the tested piece in a welding mode, and then the temperature sensor B14 is pasted on the tool by using low-temperature heat-sensitive adhesive;
the temperature sensor C16 is mounted in the following manner: firstly, making a heat sink, namely winding the lead of the temperature sensor C16 around the tested piece for several circles and then connecting the lead to the temperature sensor C16; then, the installation mode (3) described in the embodiment 1 is adopted, namely, a hole is punched on the tested piece, the temperature sensor C16 is punched in the hole, and welding is adopted for sealing;
in this embodiment, the mounting manner is all referred to as "heat sink".
The remaining components of the apparatus were the same as those of the test apparatus for evaluating the mounting manner of the temperature sensor under vacuum at low temperature described in example 1.
The method for evaluating the mounting mode of the temperature sensor under vacuum low temperature is carried out by adopting the device in the embodiment, and the specific steps are the same as the steps of the method for evaluating the mounting mode of the temperature sensor under vacuum low temperature in the embodiment 1.
The result of the comparison data shows that:
the data of the temperature sensor C16 tend to be stable more quickly, and the time is about 30 seconds longer than the time for calibrating the temperature sensor 15 to tend to be stable; the time for which the temperature sensor a 13 and the temperature sensor B14 tend to stabilize is equivalent to the time for which the calibration temperature sensor 15 tends to stabilize, which is about 2 minutes longer, and therefore it is determined that the mounting method sensitivity of the temperature sensor C16 is higher.
The values of the temperature sensor A13, the temperature sensor B14 and the temperature sensor C16 after the temperature sensors tend to be stable are equivalent to the readings of the calibrated temperature sensor 15 after the temperature sensors tend to be stable, so that the temperature measurement accuracy is not influenced by the three installation modes.
The results from example 1 and example 2 are combined to show that:
the heat sink can improve the sensitivity of the temperature sensor, and can improve the reaction sensitivity by about 1 minute and 30 seconds, but has little influence on the temperature measurement accuracy.
In example 1, the mounting method (1) and the mounting method (2) have little influence on the sensitivity and accuracy of the temperature sensor.
In the embodiment 2, the heat sink is firstly made, and then the sensitivity and the accuracy of the temperature sensor installed by adopting the installation mode (3) in the embodiment 1 are close to those of the calibration temperature sensor 15, but the installation mode has the risk of medium leakage in the piece to be tested, and can only be applied to specific occasions.
Therefore, the best mounting method of the temperature sensor is as follows: firstly, heat sink is made, and then the installation mode (1) and the installation mode (2) are adopted for installation.
Claims (10)
1. The utility model provides an evaluation vacuum temperature sensor mounting means's testing arrangement under low temperature which characterized in that: in the device, a low-temperature container holds low-temperature liquid as a tested piece; the top cover of the vacuum box is detachably and hermetically connected with the box body, and the inner wall of the vacuum box is provided with an insulating layer;
the control valve A, the vacuum valve, the control valve B, the pressure transmitter, the vacuumizing device and the computer are positioned outside the vacuum box, and the low-temperature container and the calibration temperature sensor are positioned in the vacuum box;
the pipeline comprises a low-temperature liquid conveying pipeline, a vacuumizing pipeline, a gas output pipeline and a gas pressure testing pipeline; one end of the pipeline is positioned outside the vacuum box, and the other end of the pipeline extends into the vacuum box; the low-temperature liquid conveying pipeline is positioned in the vacuum box, one end of the low-temperature liquid conveying pipeline extends into the low-temperature container, and the vacuumizing pipeline, the gas output pipeline and the gas pressure testing pipeline are positioned in the vacuum box, and the other end of the vacuumizing pipeline, the gas output pipeline and the gas pressure testing pipeline are positioned outside the low-temperature liquid;
the control valve A is arranged on the low-temperature liquid conveying pipeline; the vacuum valve is arranged on the vacuum pumping pipeline, and the vacuum pumping device is connected with the vacuum pumping pipeline; the control valve B is arranged on the gas output pipeline; the pressure transmitter is connected with the gas pressure testing pipeline;
calibrating the temperature sensor to be soaked in low-temperature liquid; a temperature sensor to be evaluated is arranged on the low-temperature container, and a lead of the temperature sensor penetrates out of the vacuum box and then is connected with a computer;
the pipeline and the lead penetrate out of the vacuum box to form a sealing structure;
the control valve A and the control valve B are sealed stop valves or switch valves.
2. The utility model provides an evaluation vacuum low temperature sensor mounting means's testing arrangement which characterized in that: the pipeline penetrating out of the vacuum box is a welded sealing structure; the lead penetrates out of the vacuum box through a vacuum electric connector arranged on the vacuum box to realize sealing connection; the main top cover of the vacuum box is connected with the box body in a detachable flange sealing mode, and the sealing structure comprises but is not limited to a fluorine rubber sealing ring, a nitrile rubber sealing ring or a polytetrafluoroethylene gasket.
3. The test device for evaluating the installation manner of the temperature sensor under vacuum and low temperature according to claim 1 or 2, characterized in that: the vacuum box is also internally provided with a radiation-proof screen, and the radiation-proof screen is connected with the top cover through a fixed connecting piece and then positioned above the low-temperature container; the radiation-proof screen is a stainless steel 304 or 316L material mirror steel plate with the thickness less than or equal to 2mm, and the shape of the radiation-proof screen is similar to the shape of the cross section of the vacuum box and is slightly smaller than the cross section of the vacuum box; the thermal conductivity of the fixed connecting piece is less than or equal to 1.0W/(m.K).
4. The test device for evaluating the installation manner of the temperature sensor under vacuum and low temperature as claimed in claim 3, wherein: when the cross section of the vacuum box is circular, the radiation-proof screen is circular, and the diameter of the radiation-proof screen is 10-20 mm smaller than the inner diameter of the vacuum box; the fixed connecting piece is a glass fiber reinforced plastic bolt.
5. The test device for evaluating the installation manner of the temperature sensor under vacuum low temperature according to claim 1 or 2, characterized in that: one end of the gas output pipeline, which is positioned outside the vacuum box, is connected with a gas recovery device.
6. The test device for evaluating the installation manner of the temperature sensor under vacuum and low temperature according to claim 1 or 2, characterized in that: the liquid level meter is a differential pressure liquid level meter, the differential pressure liquid level meter device is arranged outside the vacuum box, the differential pressure liquid level meter device is connected with two liquid pressure testing pipelines, one liquid pressure testing pipeline stretches into the vacuum box through the top cover of the vacuum box and is positioned above the liquid level of the low-temperature liquid, and the other liquid pressure testing pipeline stretches into the vacuum box through the top cover of the vacuum box and stretches into the low-temperature container from the bottom of the low-temperature container.
7. The test device for evaluating the installation manner of the temperature sensor under vacuum low temperature according to claim 1 or 2, characterized in that: the low-temperature container is made of stainless steel, and the low-temperature liquid is liquid hydrogen, liquid oxygen, liquid nitrogen, liquid helium or liquefied natural gas; the heat-insulating layer has apparent heat conductivity coefficient less than or equal to 1.5 × 10 -4 W/(m.K), and the air release rate is less than or equal to 8 x 10 -7 Pa·m 3 /(/. S.g) insulating material.
8. The test device for evaluating the installation manner of the temperature sensor under vacuum and low temperature according to claim 1 or 2, characterized in that: the vacuum box is also internally provided with a radiation-proof screen, and the radiation-proof screen is connected with the top cover through a fixed connecting piece and then positioned above the low-temperature container; the radiation-proof screen is a stainless steel 304 or 316L material mirror steel plate with the thickness less than or equal to 2mm, when the cross section of the vacuum box is circular, the radiation-proof screen is circular, and the diameter is 10-20 mm smaller than the inner diameter of the vacuum box; the fixed connecting piece is a glass fiber reinforced plastic bolt;
one end of the gas output pipeline, which is positioned outside the vacuum box, is connected with a gas recovery device;
the liquid level meter is a differential pressure liquid level meter, the differential pressure liquid level meter is arranged outside the vacuum box, the differential pressure liquid level meter is connected with two liquid pressure testing pipelines, one liquid pressure testing pipeline extends into the vacuum box through the top cover of the vacuum box and is positioned above the liquid level of the low-temperature liquid, and the other liquid pressure testing pipeline extends into the vacuum box through the top cover of the vacuum box and extends into the low-temperature container from the bottom of the low-temperature container;
the low-temperature container is made of stainless steel, and the low-temperature liquid is liquid hydrogen, liquid oxygen, liquid nitrogen, liquid helium or liquefied natural gas; the heat insulating material is a Fuji low-temperature heat insulating paper/emission screen composite product PL-900-5 or ZL-1110-2.
9. A method for evaluating the installation mode of a temperature sensor under vacuum low temperature is characterized by comprising the following steps: the method is carried out by using the device according to any one of claims 1 to 8, and comprises the following steps:
the component parts of the device and the temperature sensor to be evaluated are well installed, the control valve A, the vacuum valve, the control valve B, the pressure transmitter and the vacuumizing device are all in a closed state, and the box body of the vacuum box is in sealing connection with the top cover;
starting a test, starting a vacuumizing device, opening a vacuum valve, vacuumizing a vacuum box to below 10Pa, and closing the vacuum valve and the vacuumizing device; opening the control valve A and the pressure transmitter, injecting low-temperature liquid into the low-temperature container, gasifying the low-temperature liquid to generate gas, opening the control valve B when the pressure transmitter detects that the air pressure in the closed vacuum box reaches below 10Pa, and discharging the gas to the external environment of the vacuum box through a pipeline;
injecting low-temperature liquid into the low-temperature container until the liquid level meter displays that the low-temperature liquid reaches the specified liquid level, closing the control valve A, and stopping injecting the low-temperature liquid;
continuously acquiring and analyzing data of a calibration temperature sensor and a temperature sensor to be evaluated by adopting a computer, acquiring data from the injection of low-temperature liquid into the low-temperature container until the temperature of the low-temperature container is stable, comparing the acquired data and judging as follows:
(1) if the time for the temperature sensor to be evaluated to reach the stability is closer to the time for the calibrated temperature sensor to reach the stability, the reaction sensitivity of the temperature sensor to be evaluated is higher, and the influence of the installation mode on the sensitivity of the temperature sensor is minimum;
(2) if the reading fluctuation of the temperature sensor to be evaluated is small and no jump occurs in the process of achieving the stability, the temperature sensor has excellent performance, the installation mode has no influence on the temperature conduction,
when both (1) and (2) are satisfied, it can be said that the temperature sensor of this mounting manner has the best performance.
10. The method for evaluating the installation of the temperature sensor under vacuum low temperature according to claim 9, wherein: in the method, each component is manually controlled or automatically controlled;
the designated liquid level is that the liquid level of the low-temperature liquid reaches 1/2-2/3 of the volume of the low-temperature container;
when the gas needs to be recovered, the gas is discharged to a gas recovery device;
the temperature stability mark is that a data curve measured by a computer tends to be a straight line, the temperature fluctuation range does not exceed 1K, and when the low-temperature container is made of stainless steel, the stabilization time is 30 minutes.
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| CN115876971A (en) * | 2022-12-30 | 2023-03-31 | 中国科学院地质与地球物理研究所 | Method for online correcting water ice sample analyzer in vacuum low-temperature environment |
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| CN115876971A (en) * | 2022-12-30 | 2023-03-31 | 中国科学院地质与地球物理研究所 | Method for online correcting water ice sample analyzer in vacuum low-temperature environment |
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