Measuring device for metal linear expansion coefficient

Abstract

The utility model discloses a metal linear expansion coefficient measuring device, relates to the technical field of metal linear expansion coefficient measuring equipment, and solves the problem that in the prior art, when a metal bar to be measured is long, the installation process is inconvenient. The device comprises a base, a soaking assembly is arranged on the base, a supporting assembly is arranged in the soaking assembly in a sliding mode, the supporting assembly is used for supporting a metal bar to be measured, and a measuring assembly used for being matched with the metal bar to be measured is movably arranged at one end of the soaking assembly. The supporting assembly used for supporting the to-be-tested metal bar is slidably arranged in the soaking assembly, so that the supporting assembly can synchronously slide into the soaking assembly along with insertion of the to-be-tested metal bar when the to-be-tested metal bar is installed, and the supporting assembly gradually supports the to-be-tested metal bar along with insertion of the to-be-tested metal bar. Therefore, the installation process is more convenient, and the installation efficiency is higher.

Description

Technical Field

[0001] The utility model relates to the technical field of metal linear expansion coefficient measuring equipment, in particular to a metal linear expansion coefficient measuring device. Background Art

[0002] The measurement of the linear expansion coefficient of metals is a major part of common physical experiments. The key to this experiment is how to accurately measure the small changes in the length of a metal rod caused by temperature changes. The methods for measuring small changes are often the optical lever method and the screw micrometer method. The use of a screw micrometer has low accuracy and has a greater impact on the overall experimental data. Although the optical lever method can measure the small changes in the length of a metal rod very well, the optical lever method system is difficult to adjust and there are many physical quantities to be measured, so the experimental error introduced is relatively large. Therefore, it is necessary to provide a measuring device for the linear expansion coefficient of metals that is accurate and easy to operate.

[0003] For example, the Chinese utility model patent with publication number CN204027490U discloses an experimental device for measuring the linear expansion coefficient using a micrometer. The experimental device includes a marble bracket, a heat insulation plate, a heat insulation top, a heater, a copper heat pipe, a guide block, a sample to be tested, a heat insulation cover, a temperature sensor, a fixed bracket, a micrometer and a fixed bracket locking wrench, wherein the temperature sensor, the copper heat pipe and the heater form a constant temperature control system; the heat insulation cover is outside the circular heat insulation plate, and the heat insulation cover can be opened to facilitate students to observe the internal heating mechanism; the micrometer is installed on the axis of the sample to be tested and fixed by a fixed bracket; the fixed bracket can be rotated 180 degrees in the horizontal direction and locked by the fixed bracket locking wrench. This experimental device is stable and reliable, convenient for changing samples, fast heating and constant temperature speed, accurate measurement readings, and is particularly suitable for basic physics experiments in colleges and universities.

[0004] In this solution, the metal rod to be tested and the heat pipe are both long, and a guide block is needed inside the heat pipe to support the metal rod to be tested. At the same time, in order to maintain heating efficiency, the heat pipe is generally designed with a thinner diameter, which makes it inconvenient to install the metal rod to be tested into the heat pipe. Utility Model Content

[0005] In view of the deficiencies in the above-mentioned background technology, the utility model provides a device for measuring the linear expansion coefficient of metal, which solves the problem in the prior art that the installation process is inconvenient when the metal rod to be measured is long.

[0006] The technical solution of the utility model is implemented as follows: a device for measuring the linear expansion coefficient of metal, including a base, a heat spreader assembly is provided on the base, a support assembly is slidably provided inside the heat spreader assembly, the support assembly is used to support the metal rod to be measured, and a measuring assembly for cooperating with the metal rod to be measured is movably provided at one end of the heat spreader assembly.

[0007] Preferably, the heat equalizing assembly includes a bracket fixed on the base, a fixed end cover is fixedly provided on the bracket, the fixed end cover is fixedly connected to one end of the heat pipe, a heating unit is provided on the heat pipe, the support assembly is slidably arranged in the heat pipe, and a movable end cover is detachably provided at the other end of the heat pipe.

[0008] Preferably, a slide rail is fixedly provided inside the heat conducting tube, and the supporting assembly comprises a plurality of bases slidably matched with the slide rail, and each base is provided with a Y-shaped frame for supporting the metal rod to be tested.

[0009] Furthermore, the Y-shaped frame is provided with a roller. Adjacent bases are connected by a cable. A spring clip for fixing the end of the metal rod to be tested is provided on the Y-shaped frame near one end of the fixed end cover.

[0010] Preferably, the heating unit comprises a heating belt wound around the outer wall of the heat conducting pipe, and a heat insulating cover is fixedly provided on the base or the movable end cover, and the heat insulating cover is arranged outside the heat conducting pipe.

[0011] Preferably, a central through hole is provided on the movable end cover, a heat-insulating rod is slidably provided on the central through hole, and the movable end cover is plug-fitted with the heat-conducting pipe and the heat-insulating cover respectively.

[0012] Preferably, the measuring component includes a support arranged on a base and sliding along the axial direction of the metal rod to be measured, an eddy current displacement sensor is fixedly provided on the support, an eddy current sensor sheet is provided at the outer end of the thermal insulation rod, and the measuring end of the eddy current displacement sensor is arranged corresponding to the eddy current sensor sheet; a set screw or a locking handle for limiting the position of the support is provided on the support.

[0013] Preferably, the eddy current displacement sensor is electrically connected to the controller, the controller is electrically connected to the temperature sensor and the heating belt, and the temperature sensor is adhered and fixed to the outer wall of the metal rod to be tested.

[0014] The beneficial effects of the utility model are as follows: by sliding the support assembly for supporting the metal rod to be tested in the heat-scaling assembly, the metal rod to be tested can be slid into the heat-scaling assembly synchronously with the insertion of the metal rod to be tested during installation. The support assembly gradually supports the metal rod to be tested as the metal rod to be tested is inserted, thereby making the installation process more convenient and more efficient. In addition, by setting up the heat-scaling assembly, the temperature of the metal rod to be tested can be changed to prepare for subsequent experiments, while avoiding or reducing temperature leakage and avoiding measurement errors caused by thermal deformation of the external structure. By setting up the measuring assembly, the expansion displacement of the metal rod to be tested can be measured, thereby calculating the linear expansion coefficient. The device has a reliable structure, accurate measurement, and is easy to install. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present utility model, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 This is a schematic diagram of the external three-dimensional structure of the utility model;

[0017] Figure 2 This is a schematic diagram of the state in which the internal support assembly of the utility model supports the metal rod to be tested;

[0018] Figure 3 This is a schematic diagram of the cooperation between the base provided with a spring clip and the metal rod to be tested according to the utility model;

[0019] Figure 4 This is a schematic diagram of the state where the support assembly is located at one end when the metal rod to be tested is not installed in the utility model;

[0020] Figure 5 This is a schematic diagram of the structure of the measuring component of the utility model;

[0021] Figure 6 This is a schematic diagram of the structure of the support assembly of the utility model;

[0022] In the figure: 1: base, 2: heat-averaging component, 3: support component, 4: metal rod to be measured, 5: measuring component, 6: bracket, 7: fixed end cover, 8: heat pipe, 9: movable end cover, 10: slide rail, 11: base, 12: Y-shaped frame, 13: roller, 14: cable, 15: spring clip, 16: insulation rod, 17: heating belt, 18: insulation cover, 19: support, 20: eddy current displacement sensor, 21: locking handle, 22: temperature sensor, 23: eddy current sensor, 30: gasket. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0024] like Figure 1 , 2As shown, in Example 1, a device for measuring the linear expansion coefficient of metal includes a base 1, on which a heat spreader assembly 2 is provided, and the heat spreader assembly 2 can provide a containing and heating function, and a support assembly 3 is slidably provided in the heat spreader assembly 2, and the support assembly 3 is used to support the metal rod 4 to be measured. By sliding the support assembly for supporting the metal rod to be measured in the heat spreader assembly, the metal rod to be measured can slide the support assembly into the heat spreader assembly synchronously with the insertion of the metal rod to be measured during installation, and the support assembly gradually forms a support for the metal rod to be measured as the metal rod to be measured is inserted, so that the installation process is more convenient and the installation efficiency is higher. A measuring assembly 5 for cooperating with the metal rod 4 to be measured is movably provided at one end of the heat spreader assembly 2, and the measuring assembly can be used to measure the small changes in the metal collision of the metal rod to be measured at different temperatures, and the linear expansion coefficient of the metal rod to be measured can be calculated based on the real-time temperature.

[0025] In this embodiment, the heat equalization component 2 includes a bracket 6 fixed on the base 1, and a fixed end cover 7 is fixedly provided on the bracket 6. The fixed end cover 7 is fixedly connected to one end of the heat pipe 8, and the other end of the heat pipe 8 is detachably provided with a movable end cover 9. In this embodiment, the heat pipe 8 can be selected as a quartz tube or a metal heat pipe, and the fixed end cover 7 and the movable end cover 9 are made of conventional heat insulation materials. The fixed end cover 7 and the movable end cover 9 can block the two ends of the heat pipe, and at the same time play the role of heat preservation and avoiding heat transfer. As a further optional scheme, a heat insulation top is provided in the middle of the fixed end cover 7, and the heat insulation top is used to support the metal rod to be tested to reduce the heat transfer to the outside. A heating unit is provided on the heat pipe 8, and the support assembly 3 is slidably arranged in the heat pipe 8. The heating unit can evenly heat the metal rod to be tested in the heat pipe 8.

[0026] Embodiment 2, a device for measuring the linear expansion coefficient of metal, based on embodiment 1, as Figure 3 , 4 As shown in 6, a slide rail 10 is fixedly provided inside the heat conducting tube 8, and the supporting assembly 3 includes a plurality of bases 11 that are slidably matched with the slide rail 10, and each base 11 is provided with a Y-shaped frame 12 for supporting the metal rod 4 to be tested, which is configured as a Y-shaped frame. When the metal rod to be tested is placed on the Y-shaped frame, the metal rod to be tested can be automatically centered, which is convenient for measurement. In this embodiment, a total of four bases 11 are provided, and a slider is fixedly provided at the bottom of the base 11, which is slidably matched with the slide rail 10 through the slider.

[0027] As a further optional implementation, a roller 13 is provided on the Y-shaped frame 12 to support the metal rod to be tested. During the installation of the metal rod to be tested and the expansion of the metal rod due to heat, the metal rod to be tested can roll with the roller to reduce resistance.

[0028] As a further embodiment, adjacent bases 11 are connected by a cable 14, so as to define the maximum distance between adjacent bases. The cable 14 can be a nylon rope, a cotton thread or an iron chain. In addition, in this embodiment, a spring clip 15 for fixing the end of the metal rod 4 to be tested is provided on the Y-shaped frame 12 near one end of the fixed end cover 7 or on the base 11. In this embodiment, Figure 6 As shown, the spring clip 15 includes an integrally formed U-shaped spring sheet, and the U-shaped spring sheet has two symmetrical arc-shaped arms, which are used to clamp the metal rod to be tested. As a further optional embodiment, a gasket 30 for matching with the end of the metal rod to be tested is fixed on the Y-shaped frame, so that when installing, the metal rod to be tested and the gasket can be used to contact to push the entire base to move inside the heat transfer pipe, and the gasket moves into place when it contacts the fixed end cover.

[0029] In this embodiment, before installing the metal rod to be tested, first move all four bases 11 to the mouth of the heat conducting tube 8, then clamp the end of the metal rod to be tested with the spring clip 15 on the innermost base 11, then the metal rod to be tested pushes the base with the spring clip 15 to move inside the heat conducting tube 8, and under the traction of the cable 14, the base 11 with the spring clip 15 drives the other bases to move inside the heat conducting tube one by one until the base with the spring clip moves to the innermost position, and multiple Y-shaped frames jointly support the metal rod to be tested. When the test is finished and disassembled, slightly lift the outer end of the metal rod to be tested and pull it outward. Under the clamping of the spring clip, the innermost base pushes the other bases one by one to move to the mouth of the heat conducting tube, and finally separates the spring clip from the metal rod to be tested.

[0030] As a further optional implementation, the outermost base is fixed on the guide rail, so as to better support the outer end of the metal rod to be measured.

[0031] Embodiment 3, a device for measuring the linear expansion coefficient of metal, based on embodiment 2, the heating unit includes a heating belt 17 wound around the outer wall of the heat pipe 8, the heating belt 17 can heat the heat pipe 8, and then the metal rod to be measured inside is evenly heated through air heat transfer. In this embodiment, the heating belt is electrically connected to the auto-coupling voltage regulator, and the auto-coupling voltage regulator controls the voltage change and thus controls the heating power of the heating belt.

[0032] In addition, a heat insulation cover 18 is fixedly provided on the base 1 or the movable end cover 9, and the heat insulation cover 18 is provided outside the heat pipe 8. The heat insulation cover adopts conventional heat insulation materials to reduce heat loss and the influence of heat on other components. The movable end cover 9 is plugged with the heat pipe 8 and the heat insulation cover 18 respectively, and the plug-in matching mode is convenient for opening when installing and disassembling before and after the experiment.

[0033] As a further optional solution, a conventional heat insulating material such as a sponge insulation layer is provided on the outside of the heating belt outside the heat pipe 8 to reduce heat loss and maintain constant temperature and heating efficiency.

[0034] Embodiment 4, a device for measuring the linear expansion coefficient of metal, based on embodiment 2, as Figure 5 As shown, the measuring assembly 5 includes a support 19 slidably arranged on the base 1 along the axial direction of the metal rod 4 to be measured, an eddy current displacement sensor 20 is fixedly arranged on the support 19, a central through hole is opened on the movable end cover 9, a heat insulating rod 16 is slidably arranged on the central through hole, the heat insulating rod 16 contacts the end of the metal rod to be measured, and plays the role of transmitting the elongation of the metal rod to be measured, an eddy current sensing sheet 23 is arranged at the outer end of the heat insulating rod 16, and the measuring end of the eddy current displacement sensor 20 is arranged corresponding to the eddy current sensing sheet 23, so that the eddy current displacement sensor 20 and the eddy current sensing sheet 23 can be used to monitor the displacement. The eddy current displacement sensor 20 is electrically connected to the controller, and the controller is electrically connected to the temperature sensor 22 and the heating belt 17 respectively. In this embodiment, the temperature sensor 22 passes through the 18 heat conducting tubes 8 of the heat insulating cover and is fixed to the outer wall of the metal rod 4 to be measured, so that the temperature of the metal rod to be measured can be monitored and fed back in real time.

[0035] In addition, in this embodiment, a set screw or locking handle 21 for limiting the position of the support 19 is provided on the support 19. Specifically, in this embodiment, a slide rail is provided on the base 1 along the axial direction of the metal rod to be tested, and the support is slidably arranged on the slide rail through a slider, a latch hole is provided on the base, a U-shaped frame is fixedly provided on the support, a latch is vertically slidably arranged on the U-shaped frame, and a spring is provided between the latch and the U-shaped frame, and the latch is pressed into the pin hole under the tension of the spring to lock the position of the support. When the metal rod to be tested needs to be installed, the support is unlocked and slid away from the heat-saturating assembly, so that the movable end cover can be opened to install or remove the metal rod to be tested.

[0036] Embodiment 5, a device for measuring the linear expansion coefficient of metal, based on the above embodiment, comprises the following steps when the metal rod to be measured is installed:

[0037] First, calibration measurement is performed to maintain a constant temperature. The distance between the measuring head of the eddy current displacement sensor 20 and the eddy current sensing sheet 23 is gradually changed. The distance x is measured and recorded using existing measuring tools such as a micrometer or a vernier caliper. At the same time, the output voltage value u of the corresponding eddy current displacement sensor 20 is recorded to obtain the ux relationship curve, find the approximate linear part of the ux relationship curve, and then calculate the fitting slope k1 of the curve.

[0038] Then, the metal rod to be tested is heated by a heating belt, and the temperature reading t of the temperature sensor and the output voltage value u of the eddy current displacement sensor 20 are recorded in real time. The corresponding relationship between u and t is fitted to obtain the ut fitting curve of the metal rod to be tested, and then the fitting slope k2 of the curve is calculated. The equivalent fitting slope of the xt curve is

[0039] Expansion coefficient formula for metal rod Where l0 is the original length of the metal rod to be measured, Δt=t2-t1 is the temperature change, and Δl=l2-l1 is the corresponding elongation. The change in distance Δx between the measuring head of the eddy current displacement sensor 20 and the upper end of the insulation rod can be converted into the displacement change Δl=-Δx caused by the heating and expansion of the metal rod. The expansion coefficient of the metal rod is calculated by

[0040]

[0041] This measuring device is based on an eddy current displacement sensor, which is a non-contact linearized measurement tool that can statically and dynamically measure the distance between the measured metal conductor and the probe in a non-contact, high-linear, and high-resolution manner. The observation of small displacements and temperatures is more convenient and intuitive than traditional experiments, and the readings are real-time and accurate; the disassembly and assembly of the experimental instrument is more convenient, the experimental operation steps are simplified, the experimental error is extremely small, and the overall cost performance is high. The eddy current displacement sensor is transferred from the industrial processing field to the laboratory, which provides a new method for measuring the linear expansion coefficient of metals, and can replace traditional experiments and be used for experimental teaching. The above description is only a preferred embodiment of the utility model, and is not intended to limit the utility model. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the utility model should be included in the protection scope of the utility model.

Claims

1. A device for measuring a metal linear expansion coefficient, comprising a base (1), characterized in that: The base (1) is provided with a heat-scaling component (2), a support component (3) is slidably provided inside the heat-scaling component (2), the support component (3) is used to support the metal rod (4) to be measured, and a measuring component (5) for cooperating with the metal rod (4) to be measured is movably provided at one end of the heat-scaling component (2).

2. The device for measuring the metal linear expansion coefficient according to claim 1, characterized in that: The heat-averaging component (2) comprises a bracket (6) fixed on the base (1), a fixed end cover (7) fixedly provided on the bracket (6), the fixed end cover (7) being fixedly connected to one end of a heat-conducting pipe (8), a heating unit being provided on the heat-conducting pipe (8), a support component (3) being slidably arranged in the heat-conducting pipe (8), and a movable end cover (9) being detachably provided on the other end of the heat-conducting pipe (8).

3. The device for measuring the metal linear expansion coefficient according to claim 2, characterized in that: A slide rail (10) is fixedly provided in the heat conducting tube, and the support assembly (3) comprises a plurality of bases (11) slidably matched with the slide rail (10), and each of the bases (11) is provided with a Y-shaped frame (12) for supporting the metal rod (4) to be tested.

4. The device for measuring the metal linear expansion coefficient according to claim 3, characterized in that: The Y-shaped frame (12) is provided with a roller (13).

5. The device for measuring the metal linear expansion coefficient according to claim 3 or 4, characterized in that: Adjacent bases (11) are connected via cables (14).

6. The device for measuring the metal linear expansion coefficient according to claim 5, characterized in that: A spring clip (15) for fixing the end of the metal rod (4) to be tested is provided on the Y-shaped frame (12) near one end of the fixed end cover (7).

7. The device for measuring the metal linear expansion coefficient according to any one of claims 2 to 4 and 6, characterized in that: The heating unit comprises a heating belt (17) wound around the outer wall of the heat conducting pipe (8), and a heat insulating cover (18) is fixedly provided on the base (1) or the movable end cover (9), and the heat insulating cover (18) is arranged outside the heat conducting pipe (8).

8. The device for measuring the metal linear expansion coefficient according to claim 7, characterized in that: The movable end cover (9) is provided with a central through hole, on which a heat insulating rod (16) is slidably provided, and the movable end cover (9) is plug-fitted with the heat conducting pipe (8) and the heat insulating cover (18) respectively.

9. The device for measuring the metal linear expansion coefficient according to claim 8, characterized in that: The measuring assembly (5) comprises a support (19) slidably arranged on the base (1) along the axial direction of the metal rod (4) to be measured, an eddy current displacement sensor (20) being fixedly arranged on the support (19), an eddy current sensing sheet (23) being arranged at the outer end of the heat insulating rod (16), and a measuring end of the eddy current displacement sensor (20) being arranged corresponding to the eddy current sensing sheet (23); and a set screw or a locking handle (21) for limiting the position of the support (19) being arranged on the support (19).

10. The device for measuring the metal linear expansion coefficient according to claim 9, characterized in that: The eddy current displacement sensor (20) is electrically connected to the controller, the controller is electrically connected to the temperature sensor (22) and the heating belt (17), and the temperature sensor (22) is glued and fixed to the outer wall of the metal rod (4) to be tested.

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