KR100400100B1 - Method and apparatus for stabilizing the length of engineering materials using the thermophysical properties of gallium - Google Patents

Abstract

The present invention relates to a more precise and accurate measurement in a place requiring high precision measurement by stabilizing the length of the engineering material that changes according to the external environment, in particular the solid phase on the outer periphery of the engineering material requiring precision measurement using the characteristics of gallium The present invention relates to an apparatus and method for stabilizing the length of an engineering material by protecting the engineering material with gallium consisting of a liquid phase.

The length of the material changes according to the external environmental temperature change and the material's intrinsic properties. Among them, the intrinsic properties of the material cannot be changed, so that the length of the engineering material can be stabilized by reducing the external temperature change. The engineering material made by the above method is very insensitive to the change of length in the place where the external temperature change does not change greatly, so it can be very useful in the laboratory, precision measurement laboratory, etc. that require precision measurement or length stabilization. .

Description

Method and apparatus for stabilizing the length of engineering materials using the thermophysical properties of gallium

The present invention relates to an experimental apparatus and method for experimenting the temperature characteristics of a material, the experimental apparatus comprises a small thermostat and an experimental apparatus for measuring the length of the material, the small thermostat is the temperature change when the state changes Is arranged so that light is transmitted through a portion of one side of the thermostat in order to measure the length of the material in the thermostat and to measure the length of the material in the thermostat. An experimental apparatus and method for experimenting with the temperature characteristics of a material characterized by.

In general, laboratories and research institutes that require precise measurement are using a method of stabilizing changes in the length of engineering materials by maintaining a constant temperature in the room such as an electronic constant temperature system to stabilize the length of engineering materials.

This method is expensive to install, maintain, and repair a laboratory. Also, such a change in temperature due to human movement or the opening and closing of a door and the operation of laboratory equipment has a significant effect. It is very difficult and expensive to keep the temperature of the thermostat at the same temperature even with the change.

However, in order to perform a simple constant temperature experiment, a small scale constant temperature is often required, and the whole constant temperature chamber must be maintained at the same temperature, and in this case, it is very disadvantageous in terms of maintenance and repair and is not good in effect.

The present invention proposes to solve the above problems, and proposes a constant temperature chamber structure that can easily maintain a small temperature chamber.

In another aspect, the present invention proposes a thermostatic chamber structure that can put the material of interest in the small-scale thermostatic chamber and confirm the change in length according to the temperature change.

As described above, the engineering material of interest in the small temperature chamber is placed inside the chamber so as not to be directly exposed to the outside air, and the length of the engineering material is stabilized during the experiment by not being affected by the external temperature change. It is to provide the reliability and convenience for research and experiment by making own small and small chambers inexpensively and easily in laboratories or laboratories requiring high precision measurement according to temperature change.

1 is a state graph of gallium that changes from a solid to a liquid phase with respect to temperature

2 is a state graph of gallium which changes from a liquid phase to a solid phase with respect to temperature

3 is a cross-sectional view of the device implemented in the present invention.

3A is a simplified perspective view of a differential plane mirror interferometer for measuring varying lengths in the present invention.

4 is a graph that changes the outside temperature by 0.5 ℃

5 is a graph of temperature change of gallium against an external temperature change of 0.5 ° C.

6 is a graph showing the change in length of alumina versus temperature change of gallium

* Explanation of symbols for main parts of the drawings

10 Copper chamber 20 Standard mirror 30 Target mirror 40 Heating plate 50 Temperature sensor 100 Gallium 200 Alumina

The present invention relates to the fabrication and maintenance of a small temperature chamber to observe the change in the length of the engineering material with respect to the temperature, etc., wherein the material that hardly changes the temperature at the time of state change is arranged around the small temperature chamber and the state change The temperature is controlled to be maintained for a long time in a stable state. In another aspect, the present invention is configured to measure the length change of the material in the thermostat so that the light is transmitted to a portion of one side of the thermostat so that the length can be measured in a non-contact manner.

To better understand the characteristics of the material according to the temperature is as follows.

All materials vary in length depending on the properties of the material and the change in external temperature. The degree of change of a substance is determined by the formula shown in Equation 1.

(Equation 1)

The length of the material change in the above (Equation 1) ( ) Is the intrinsic length (L) ) And temperature change ( Is multiplied by Since the material constant is an inherent property of the material, it may contribute to stabilization to some extent by using a small one of such material constants. However, even if a small material constant in an engineering material is used, the length of the material may change due to external temperature changes. This external temperature change ( It is natural to stabilize the length of the material by decreasing the size of?).

As the material disposed around the thermostat, a material capable of maintaining a constant temperature for a long time at room temperature when the state changes is suitable. Although the present invention employs gallium, this is only one example, and the selection of materials other than gallium will naturally belong to the scope of the present invention. The following briefly introduces the properties of gallium.

Every substance has its own freezing and melting point. Therefore, all materials need energy to change from melting or freezing, from solid to liquid, or from liquid to solid. At this time, it has a latent heat of fusion that does not cause a temperature change of the material during the state change. This intrinsic latent heat is achieved at temperatures above or below room temperature, but gallium is characterized at room temperature (29.77 ° C), and the melting point of gallium is insensitive to environmental changes such as barometric pressure and humidity. It has excellent temperature stability and maintains a constant temperature for a long time without any external device. Therefore, at room temperature (29.77 ℃) wrapped around the outside of the thermostat with gallium and keep the temperature of gallium at 29. ℃ ~ 30 ℃ can maintain the temperature of gallium at 29.77 ℃, so the temperature inside the thermostat also It can be maintained. Since the constant temperature can be maintained precisely through the simple structured device as described above, it is possible to study the properties of the material under the influence of temperature change.

The melting and freezing characteristics of gallium will be briefly described with reference to FIGS. 1 and 2.

FIG. 1 shows a graph in which gallium is present in a solid state and then has a section in which a solid phase and a liquid phase exist together when heat is applied, and then continues to be added in a liquid form when heat is continuously applied. FIG. 2 shows a graph in which a liquid phase and a solid phase exist past a super cooling point when the heat is reduced in a liquid state, and the solid state exists when the heat is further reduced. Looking at the characteristic graph of Figures 1 and 2 it can be seen that the same temperature is maintained for a long time when the state changes. The melting state (see FIG. 1) and the frozen state (see FIG. 2) are different depending on the presence or absence of a supercooling point, but this can be maintained at the level of temperature required by the industry. Or frozen state).

Hereinafter, a device capable of maintaining the temperature of the thermostat using gallium and one embodiment of experimenting with the temperature change using the thermostat will be described.

Figure 3 shows a cross-sectional view of the thermostatic bath proposed in the present invention and the apparatus for testing the degree of change in length according to the temperature change by applying the thermostat.

First, the structure of the thermostat and the control method for maintaining the constant temperature are mentioned.

This thermostat is designed to test the length change according to the temperature change of the cylindrical alumina (200, Cylindrical Alumina) and is designed to surround the cylindrical alumina.

The thermostat is composed of a copper chamber 10, a temperature sensor 50, and a heating plate 40, the outer diameter of which is larger than the measurement piece. Referring to the process of maintaining a constant temperature, first, the liquid gallium is injected through the gallium inlet 11, and then the temperature is lowered until the entire chamber is converted to a solid phase of the gallium. Then, when heat is applied to the outside of the copper chamber 10 through the heating plate 40, the temperature of the copper chamber rises, and when the state change temperature of gallium, that is, 29.77 ° C., the gallium starts to change state. The state change section is possible by measuring the temperature of the temperature sensor 50. The temperature sensed by the temperature sensor is transmitted to the central control unit 400 and determines whether to apply a voltage to the heating plate by checking the transferred temperature. A graph of the temperature change detected by the temperature sensor while applying heat through the heating plate 40 is shown in FIG. 1. If the ambient temperature of the thermostat is less than 29 ℃ gallium inside the thermostat will want to return to the solid phase, which can be recognized by confirming the temperature change of the temperature sensor. At this time, if the heating plate is heated again, the internal temperature of the thermostat can maintain a constant temperature without any difficulty.

If you explain step by step the process of maintaining the above temperature

1. Inject liquid gallium into the thermostat.

2. Maintain the whole thermostat below 28 ℃ so that the gallium changes to solid phase.

3. While heating the copper chamber with a heating plate 40, the temperature sensor 50 senses the temperature inside the thermostat.

4. If the sensed temperature is around 29.80 ℃, it can be confirmed that gallium is in the process of changing from solid phase to liquid phase, and the heat supply through the heating plate is stopped.

5. When the temperature drops below 29.70 ℃ through the temperature sensor, heat is supplied through the heating plate.

6. Repeat steps 4 and 5 to maintain the temperature in the cabinet between 29.70 ° C and 29.80 ° C.

The shape and size of the copper chamber may be determined by those skilled in the art according to the shape and size of the measurement piece, and the shape or size of the copper chamber does not limit the scope of the present invention.

Hereinafter, an apparatus and a process for experimenting with a temperature change of alumina by using the thermostat will be described.

The thermostat of this experimental apparatus is arranged to surround the thermostat with gallium as mentioned above, and the cylindrical alumina (200, Cylindrical Alumina) to be measured in this experiment is placed inside the copper chamber (10, Copper chamber) on the temperature sensor 50. Installed between the target mirror (30, Target mirror) and the reference mirror (20, Reference mirror), the temperature sensor 50 is attached to the outer periphery of the cylindrical alumina, gallium is injected through the gallium inlet (11) and the copper chamber ( On the outer circumference of 10), a heating plate 40 was installed.

Figure 3a shows a perspective view of a differential plane mirror interferometer, the present apparatus used a differential plane mirror interferometer (1) to measure only the change in the length of the material to stabilize the length. The differential planar mirror interferometer (1) is a beam emitted through the exit (2, Fig. 3a) of the laser beam through the half wave plat and the quarter wave plat passes through the hole (21) Reflected by the target mirror 30, and the reflected beam is incident again to the outlet 2, reflected by the target mirror 30 through another hole 22 through the outlet 4, and then exited. It comes back to (4), which is called measuring beam. Similarly, the beam emitted from the hole 3 (see FIG. 3A) of the differential plane mirror interferometer 1 is reflected at the surface of the reference mirror 20 and is incident again into the hole 3, and the incident beam is passed through the outlet 5. The beam that emits again and is reflected back by the reference mirror 20 and enters the entrance 5 is called a reference beam. The length of the engineering material is measured by the interference between the measuring beam and the reference beam. In the above process, the holes 21 and 22 located in the reference mirror are positioned diagonally to each other. The detailed description of the differential plane mirror interferometer is related to known techniques and devices and is not described in detail.

Initial values of each material initially used in the experiment of the present invention are as follows.

The length of the alumina 200 to be measured was 300 mm, and the thickness of the target mirror 30 was excluded because the thickness of the target mirror 30 did not affect the alumina 200 in the present experiment. It was set as 312.5 mm including the thickness of 12.5 mm. In the above process, the reflection mirror 20 may affect the length of the alumina 200 measured by the temperature change, but the amount of change of the reflection mirror and the alumina corresponding to the temperature change of 1 ° C is 0.006125 μm and 8.4 μm, respectively. The ratio of the reflecting mirror to the change in is 0.073%, which is a negligible value. The amount of gallium was tested at 800 g. That is, the length measured in this experiment is the sum of the thickness of the reflecting mirror and the length of the alumina, and the value of the length of the reflecting mirror is subtracted to change the length of the alumina.

Experimental methods were tested by separating the gallium from the liquid phase to the solid phase as opposed to the experiment to change the state from the solid phase to the liquid phase.

The sequence of experiments in which gallium is changed from a solid state to a liquid state is that gallium is introduced into the gallium inlet 11 from a liquid state, the temperature is lowered to room temperature, and a gallium seed is inserted into a solid state. Then, the temperature of the copper chamber 10 was maintained at about 30 ° C. by using the temperature sensor 50 while gradually heating with a heating plate. At this time, the outside temperature was changed by about 1 ° C. ) Was measured.

4, 5 and 6 are graphs of the results of the experiment conducted in the same manner as described above.

Figure 4 is a graph of the external temperature, Figure 5 is a temperature graph of alumina as a measurement material, which is the same as the temperature change of gallium. Figure 6 is a graph of the length change of alumina at the same time point in the two graphs. The measurement time sampled one section of the time measured for two hours. The change in the external temperature of FIG. 4 changes the temperature drop from 25.4 ° C to 24.8 ° C with a difference of 0.6 ° C. In this case, the temperature change of alumina in the copper chamber, that is, the temperature change of gallium, is 29.769 ° C to 29.770 ° C. It is changing within 1/1000 ℃, the length change of the alumina with respect to the temperature change of Figure 6 is 5.435 ㎛ ~ 5.465 ㎛ is a length change within 0.030 ㎛. As a result of this experiment, considering that the change in length with respect to the change of temperature 0.6 ℃ for alumina 300 mm is 1.512 μm, the result of the experiment is changing within 0.030 μm so that the change in length for temperature change can be stabilized within about 2%. It can be seen that the reliability is increased by stabilization with respect to the length.

As described above, the method of stabilizing the length of an engineering material by protecting the engineering material with a gallium composed of a solid and a liquid on the outer circumference of the engineering material by using the properties of gallium in an engineering material requiring precise measurement is characterized by large changes in external temperature. It is very insensitive to the change of length in the unchanged place, so it can be very useful in the laboratory and precision measurement labs that require precision measurement or length stabilization. And maintenance costs are reduced and there is an effect that can be used easily.

Claims (4)

In the apparatus for testing the temperature characteristics of the material The thermostat for maintaining a constant temperature is composed of a material arranged to surround the outside, the material is composed of a material that maintains a constant temperature when the state changes, the heating plate 40 and the material that can apply heat to the material Apparatus for experiments with the temperature characteristics of the material, characterized in that consisting of a temperature sensor 50 capable of measuring the temperature of the central control unit 400 to maintain the temperature of the thermostat by administering the heating plate and the temperature sensor The method of claim 1 Apparatus for testing the temperature characteristics of the material, characterized in that the material arranged to surround the outside of the thermostat made of gallium The method according to claim 1 or 2 The target mirror 30 is located on one side of the measurement piece located inside the thermostat, the reference mirror 20 is located on the other side, and one side of the thermostat is configured as a transparent window so that a laser can be incident to the transparent window. Part of the incident laser is reflected off the reference mirror And a part of which is reflected from a target mirror and analyzes the interference result by interfering the reflected light to detect a change in length of the measurement piece. The thermostat includes a material disposed to surround the outside, a temperature of a material including a heating plate 40 capable of applying heat to the material, a temperature sensor 50 capable of measuring the temperature of the material, and a central controller 400. In the device for testing the characteristics Sensing the temperature of the material surrounding the outside of the thermostat; Comparing and determining whether the sensed temperature is a constant temperature; Applying heat to the heating plate when the temperature is lower than a predetermined temperature as a result of the comparison; Blocking the heat supply to the material surrounding the thermostat by cutting off the voltage applied to the heating plate when the comparison result is over a predetermined temperature; Consists of The comparison step and the step of controlling the voltage on the heating plate are performed by a central controller to test the temperature characteristics of the material.