Metal linear expansion coefficient measuring device

Abstract

The utility model discloses a metal linear expansion coefficient measuring device, which belongs to the technical field of metal linear expansion coefficient measurement and comprises a first base and a second base, a heating mechanism and an optical lever are arranged on the first base, and a transmitting mechanism, a photoresistor sensor and a measuring scale are arranged on the second base. A to-be-measured metal pipe is sleeved with the heating mechanism, and a probe of the electronic thermodetector is placed in the to-be-measured metal pipe. According to the utility model, laser is adopted as a transmitting device, reflected light rays are projected into the photoresistor sensor on the measuring scale after being reflected by the plane mirror, and when the temperature rises and the metal tube to be measured has a linear expansion phenomenon, the angle of the plane mirror is changed, and the reflected light rays also have angle deflection; the light of the laser can be directly observed by naked eyes in a dark environment, so that a teacher can clearly observe the change of the angle of the light in experiment demonstration, and the experiment effect is more obvious and intuitive.

Description

Technical Field

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

[0002] Most objects have the property of thermal expansion and contraction, which is caused by the intensification or weakening of the thermal motion of the heated molecules inside the object. For isotropic objects, the expansion coefficient of the object in all directions is the same and constant. The ratio of the change in length of a substance to its length at 0°C for every 1°C change in temperature is called the "linear expansion coefficient", also known as the linear expansion coefficient. It is one of the important parameters describing the thermal expansion of materials. The linear expansion coefficient of metals is a very important parameter in engineering design, precision instrument manufacturing and material welding processing. Therefore, in university physics experiments, "measurement of metal linear expansion coefficient" is an important experiment in the force and heat part. The measurement of metal linear expansion coefficient can be divided into electric heating method, running water heating method, steam heating method, etc. according to different heating methods. According to different measurement methods, it can be divided into micrometer method, combination method, monochromatic light wedge interference method, optical lever method, sensor measurement method, etc. Among them, the experiment of measuring metal linear expansion coefficient using optical lever method is one of the projects offered in the general physics experiment course of universities. It can not only allow students to master the principle of measuring tiny quantities by optical lever amplification method, but also further understand the physical meaning of metal linear expansion coefficient.

[0003] At present, the most common method for measuring the linear expansion coefficient of metals is to use electric heating of the metal rod to be tested, and to use a thermometer at multiple temperature working points. Generally, a ruler-reading telescope and an optical lever are used to measure the length change of the metal rod caused by the temperature difference in different states. However, the ruler-reading telescope has a small observation range, and it is difficult to find an accurate and clear image, which is not easy to demonstrate to students. Utility Model Content

[0004] In view of the problems existing in the prior art, the utility model provides a device for measuring the linear expansion coefficient of metal, which has the advantages of intuitively displaying experimental results and more obvious experimental effects. It solves the problem that in the prior art, a ruler-reading telescope and an optical lever are used to measure the length change of a metal rod caused by temperature differences in different states, while the ruler-reading telescope has a small observation range, making it difficult to find an accurate and clear image, and is not easy to demonstrate to students.

[0005] The utility model is implemented as follows: a metal linear expansion coefficient measuring device comprises a first base and a second base, wherein the first base is provided with a heating mechanism and an optical lever, and the second base is provided with a transmitting mechanism, a photoresistor sensor and a ruler, the metal tube to be measured is sleeved inside the heating mechanism, and the probe of the electronic thermometer is placed inside the metal tube to be measured.

[0006] As a preferred embodiment of the utility model, the heating mechanism includes a protective sleeve, a heating tube is arranged inside the protective sleeve, the metal pipe to be tested is inserted into the heating tube, a preset switch, an adjusting switch and a compensation lamp are arranged on one side of the protective sleeve, and the preset switch, the adjusting switch and the compensation lamp are fixedly mounted on the first base.

[0007] As a preferred embodiment of the utility model, a support column is fixedly connected to one side of the upper surface of the first base, a platform is fixedly connected to the top of the protective sleeve and the support column, a metal sleeve is fixedly installed on the platform, and the metal sleeve is fixedly sleeved on the top of the metal pipe to be tested.

[0008] As a preferred embodiment of the utility model, the rear toe of the optical lever is placed on the metal sleeve, and the front toe of the optical lever is placed on the platform.

[0009] As a preferred embodiment of the utility model, a support rod and a slide rail are fixedly connected to the upper surface of the second base, a lifting rod is slidably connected to the slide rail, a second fastening knob is provided on one side of the slide rail, the photoresistor sensor is fixedly installed on the lifting rod, a connecting plate is fixedly connected to one side of the slide rail, the upper end of the ruler is fixedly connected to the connecting plate, and the bottom of the ruler rests on the upper surface of the second base.

[0010] As a preferred embodiment of the utility model, a slit is provided on the photoresistor sensor, and a marking line is provided on a side of the photoresistor sensor close to the ruler.

[0011] As a preferred embodiment of the utility model, the launching mechanism includes a fixed rod and a movable rod, one end of the fixed rod is fixedly connected to a sliding sleeve, the sliding sleeve is slidably mounted on the support rod, a first tightening knob is arranged on one side of the sliding sleeve, the fixed rod is hinged to the movable rod, a screw rod is fixedly connected to the fixed rod, a movable groove is arranged on the movable rod, one end of the screw rod passes through the movable groove and a nut is arranged on the threaded sleeve.

[0012] As a preferred embodiment of the utility model, one end of the fixed rod and the movable rod are both fixedly connected to a clamping plate, and a laser pen is clamped in the clamping plate.

[0013] Compared with the prior art, the beneficial effects of the utility model are as follows:

[0014] 1. The utility model adopts laser as the transmitting device. After being reflected by the plane mirror, the reflected light hits the photoresistor sensor on the ruler. When the temperature rises and the metal tube to be measured undergoes linear expansion, the angle of the plane mirror changes, and the reflected light also undergoes angle deflection. The laser light can be directly observed with the naked eye in a dark environment, which is convenient for teachers to let students clearly observe the changes in the light angle during the experimental demonstration, making the experimental effect more obvious and intuitive.

[0015] 2. The utility model moves the photoresistor sensor to find the specific position of the light spot. When the laser is reflected and irradiated to the slit, the indicator light of the photoresistor sensor lights up and the buzzer sounds, and the reading of the ruler indicated by the marking line is recorded. By setting the buzzer, the experimental effect can be made more obvious. By using the slit of the photoresistor sensor to read, the reading error of the experiment can be reduced and the accuracy can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0017] Figure 2 It is a schematic diagram of a first partial cutaway three-dimensional structure of the utility model;

[0018] Figure 3 It is a schematic diagram of a second partial cutaway three-dimensional structure of the utility model;

[0019] Figure 4 It is a schematic diagram of a partial three-dimensional structure of the utility model.

[0020] In the figure: 1. first base; 2. heating mechanism; 3. transmitting mechanism; 4. optical lever; 5. photoresistor sensor; 501. slit; 502. marking line; 6. ruler; 7. lifting rod; 8. supporting rod; 9. first fastening knob; 10. second base; 11. supporting column; 12. platform; 13. electronic thermometer; 14. metal pipe to be measured; 15. metal sleeve; 16. second fastening knob; 17. slide rail; 18. connecting plate; 201. preset switch; 202. adjusting switch; 203. compensation lamp; 204. protective sleeve; 205. heating tube; 301. fixing rod; 302. movable rod; 303. screw rod; 304. movable groove; 305. nut; 306. splint; 307. laser pen; 308. sliding sleeve. DETAILED DESCRIPTION

[0021] In order to further understand the content, features and effects of the utility model, the following embodiments are given as examples and described in detail with reference to the accompanying drawings.

[0022] The structure of the utility model is described in detail below in conjunction with the accompanying drawings.

[0023] like Figures 1 to 4 As shown, a metal linear expansion coefficient measuring device provided by an embodiment of the utility model includes a first base 1 and a second base 10, the first base 1 is provided with a heating mechanism 2 and an optical lever 4, the second base 10 is provided with a transmitting mechanism 3, a photoresistor sensor 5 and a ruler 6, the metal tube 14 to be measured is sleeved inside the heating mechanism 2, and the probe of the electronic thermometer 13 is placed inside the metal tube 14 to be measured.

[0024] Furthermore, the heating mechanism 2 includes a protective sleeve 204, a heating tube 205 is sleeved inside the protective sleeve 204, the metal tube 14 to be tested is inserted into the heating tube 205, a preset switch 201, an adjusting switch 202 and a compensation lamp 203 are provided on one side of the protective sleeve 204, the preset switch 201, the adjusting switch 202 and the compensation lamp 203 are fixedly installed on the first base 1, a support column 11 is fixedly connected to one side of the upper surface of the first base 1, the protective sleeve 204 and the top of the support column 11 are fixedly connected to a platform 12, a metal sleeve 15 is fixedly installed on the platform 12, and the metal sleeve 15 is fixedly sleeved on the top of the metal tube 14 to be tested.

[0025] In the present application, the heating mechanism 2 is used to heat the metal tube 14 to be tested, and the temperature of the metal tube is monitored in real time by the electronic thermometer 13. When working, turn on the power switch, press the preset switch 201, enter the preset state, touch the adjustment switch 202, adjust the preset temperature, and after the adjustment is completed, press the preset switch 201 to exit the preset state and enter the working state. When the temperature reaches the preset temperature, pay attention to whether the compensation switch is on. It is normal if it is on. Since the temperature is continuous, it will continue to heat up and cool down. By adjusting the temperature, it will rise to a certain temperature point and then start to cool down. When the temperature drops to a position 10°C higher than the preset temperature, turn on the compensation switch and turn it clockwise to the 40V position for compensation. When the temperature drops slowly, it can be considered that the system heating and heat dissipation are relatively stable, and the relatively stable temperature value is recorded.

[0026] Furthermore, the rear toe of the optical lever 4 is placed on the metal sleeve 15 , and the front toe of the optical lever 4 is placed on the platform 12 .

[0027] In the present application, an adjustment knob is provided at the bottom of the optical lever 4, which can facilitate the adjustment of the distance between the rear toe and the front toe.

[0028] Furthermore, a support rod 8 and a slide rail 17 are fixedly connected to the upper surface of the second base 10, a lifting rod 7 is slidably connected to the slide rail 17, a second fastening knob 16 is provided on one side of the slide rail 17, a photoresistor sensor 5 is fixedly installed on the lifting rod 7, a connecting plate 18 is fixedly connected to one side of the slide rail 17, an upper end of the ruler 6 is fixedly connected to the connecting plate 18, a bottom of the ruler 6 is against the upper surface of the second base 10, a slit 501 is provided on the photoresistor sensor 5, and a marking line 502 is provided on the side of the photoresistor sensor 5 close to the ruler 6.

[0029] In the present application, a buzzer is installed on the photoresistor sensor 5, and the lifting rod 7 can be raised and lowered along the slide rail 17. After the height is adjusted, it is fixed by the second tightening knob 16 to achieve the adjustment of the position of the photoresistor sensor 5. The specific position of the light spot is found by moving the photoresistor sensor 5. When the laser is reflected and irradiated to the slit 501, the indicator light of the photoresistor sensor 5 lights up and the buzzer sounds, and the reading of the ruler 6 indicated by the marking line 502 is recorded. By setting the buzzer, the experimental effect can be made more obvious. By using the slit 501 of the photoresistor sensor 5 for reading, the reading error of the experiment can be reduced and the accuracy can be improved.

[0030] Furthermore, the launching mechanism 3 includes a fixed rod 301 and a movable rod 302, one end of the fixed rod 301 is fixedly connected to a sliding sleeve 308, the sliding sleeve 308 is slidably mounted on the support rod 8, a first tightening knob 9 is arranged on one side of the sliding sleeve 308, the fixed rod 301 is hinged to the movable rod 302, a screw rod 303 is fixedly connected to the fixed rod 301, a movable groove 304 is arranged on the movable rod 302, one end of the screw rod 303 passes through the movable groove 304 and a nut 305 is threadedly mounted on the screw rod 303, one end of the fixed rod 301 and the movable rod 302 are fixedly connected to a splint 306, and a laser pen 307 is clamped in the splint 306.

[0031] In the present application, two clamps 306 clamp the laser pen 307. When installing the laser pen 307, the two clamps 306 are opened by pressing the movable rod 302 downward, and the laser pen 307 is placed on the lower clamp 306. Then, the movable rod 302 is moved upward to clamp the laser pen 307 between the two clamps 306. Then, the nut 305 is tightened to fix the positions of the clamps 306 and the laser pen 307. The height of the laser pen 307 can be adjusted by sliding the sleeve 308 on the support rod 8 so that the laser can return to the original emission position.

[0032] The present application adopts laser as the transmitting device. After being reflected by a plane mirror, the reflected light hits the photoresistor sensor 5 on the ruler 6. When the temperature rises and the metal tube 14 to be measured undergoes linear expansion, the angle of the plane mirror changes, and the reflected light also undergoes an angle deflection. The laser light can be directly observed with the naked eye in a dark environment, which is convenient for teachers to let students clearly observe the changes in the light angle during the experimental demonstration, making the experimental effect more obvious and intuitive.

[0033] The working principle of this utility model:

[0034] Place the optical lever 4 on the platform 12, with its rear tip placed on the metal sleeve 15, the mirror surface of the optical lever 4 in the vertical direction, the probe of the electronic thermometer 13 placed inside the metal tube 14 to be measured, and the laser pen 307 placed 1.5-2m in front of the optical lever 4. Turn on the laser pen 307 and adjust its height so that the laser can return to the original emission position. Then measure the distance from the ruler 6 to the mirror surface of the plane mirror, record it in a table, then turn on the power switch, press the preset switch 201 to enter the preset state, touch the adjustment switch 202 to adjust the preset temperature, after the adjustment is completed, press the preset switch 201 to exit the preset state and enter the working state. When the temperature reaches the preset temperature, pay attention to whether the compensation switch is on. If it is on, it is normal. Since the temperature is continuous, it will continue to heat up and cool down. By adjusting the temperature It will rise to a certain temperature point and then begin to cool down. When the temperature drops to a position 10°C higher than the preset temperature, open the compensation switch and turn it clockwise to the 40V position for compensation. When the temperature drops slowly, it can be considered that the system's heating and heat dissipation are relatively stable. Note the relatively stable temperature value and move the photoresistor sensor 5. When the first beep is heard, record the reading of the ruler 6 at this time, then turn off the compensation switch and reset it again. When the temperature reaches the preset value, compensate. When it is stable, move the photoresistor sensor 5 again to find the specific position of the light spot and record the reading of the ruler at this time, and so on, until the specified number of groups are measured, then stop heating, remove the light lever 4, and after cooling slightly, use a vernier caliper to measure the distance from the rear toe to the midpoint of the two front toes, measure three times respectively, record the data in a table, and perform data processing and error analysis.

[0035] In summary, the device for measuring the linear expansion coefficient of metal adopts laser as the transmitting device. After being reflected by the plane mirror, the reflected light hits the photoresistor sensor 5 on the ruler 6. When the temperature rises and the metal tube 14 to be measured undergoes linear expansion, the angle of the plane mirror changes, and the reflected light also undergoes an angle deflection. The laser light can be directly observed with the naked eye in a darker environment, which is convenient for teachers to let students clearly observe the change in the angle of the light during the experimental demonstration, making the experimental effect more obvious and intuitive. The specific position of the light spot is found by moving the photoresistor sensor 5. When the laser is reflected and irradiated to the slit 501, the indicator light of the photoresistor sensor 5 lights up and the buzzer sounds, and the reading of the ruler 6 indicated by the mark line 502 is recorded. By setting the buzzer, the experimental effect can be made more obvious. By using the slit 501 of the photoresistor sensor 5 for reading, the reading error of the experiment can be reduced and the accuracy can be improved.

[0036] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0037] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A device for measuring a metal linear expansion coefficient, comprising a first base (1) and a second base (10), characterized in that: The first base (1) is provided with a heating mechanism (2) and a light lever (4), the second base (10) is provided with a transmitting mechanism (3), a photoresistor sensor (5) and a ruler (6), the metal tube (14) to be measured is sleeved inside the heating mechanism (2), and the probe of the electronic thermometer (13) is placed inside the metal tube (14) to be measured.

2. A metal linear expansion coefficient measuring device as claimed in claim 1, characterized in that: The heating mechanism (2) comprises a protective sleeve (204), a heating tube (205) is sleeved inside the protective sleeve (204), the metal pipe (14) to be tested is plugged into the heating tube (205), a preset switch (201), an adjustment switch (202) and a compensation lamp (203) are arranged on one side of the protective sleeve (204), and the preset switch (201), the adjustment switch (202) and the compensation lamp (203) are fixedly mounted on the first base (1).

3. A metal linear expansion coefficient measuring device as claimed in claim 2, characterized in that: A support column (11) is fixedly connected to one side of the upper surface of the first base (1); a platform (12) is fixedly connected to the top of the protective sleeve (204) and the support column (11); a metal sleeve (15) is fixedly mounted on the platform (12); and the metal sleeve (15) is fixedly sleeved on the top of the metal pipe (14) to be tested.

4. A metal linear expansion coefficient measuring device as claimed in claim 3, characterized in that: The rear tip of the optical lever (4) is placed on the metal sleeve (15), and the front tip of the optical lever (4) is placed on the platform (12).

5. A metal linear expansion coefficient measuring device as claimed in claim 1, characterized in that: The upper surface of the second base (10) is fixedly connected with a support rod (8) and a slide rail (17); a lifting rod (7) is slidably connected to the slide rail (17); a second tightening knob (16) is provided on one side of the slide rail (17); the photoresistor sensor (5) is fixedly mounted on the lifting rod (7); a connecting plate (18) is fixedly connected to one side of the slide rail (17); the upper end of the ruler (6) is fixedly connected to the connecting plate (18); and the bottom of the ruler (6) abuts against the upper surface of the second base (10).

6. A metal linear expansion coefficient measuring device as claimed in claim 1, characterized in that: The photoresistor sensor (5) is provided with a slit (501), and a marking line (502) is provided on a side of the photoresistor sensor (5) close to the ruler (6).

7. A metal linear expansion coefficient measuring device as claimed in claim 5, characterized in that: The launching mechanism (3) comprises a fixed rod (301) and a movable rod (302); one end of the fixed rod (301) is fixedly connected to a sliding sleeve (308); the sliding sleeve (308) is slidably sleeved on a support rod (8); one side of the sliding sleeve (308) is provided with a first tightening knob (9); the fixed rod (301) is hinged to the movable rod (302); a screw rod (303) is fixedly connected to the fixed rod (301); a movable groove (304) is provided on the movable rod (302); one end of the screw rod (303) passes through the movable groove (304) and a nut (305) is threadedly sleeved thereon.

8. A metal linear expansion coefficient measuring device as claimed in claim 7, characterized in that: One end of each of the fixed rod (301) and the movable rod (302) is fixedly connected to a clamping plate (306), and a laser pen (307) is clamped inside the clamping plate (306).

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