Liquid filling method and device for carrying out such method

Abstract

According to one embodiment of the present invention, a method for filling a narrow tube with a closed end with a liquid includes the steps of injecting a liquid volatile material into the tube; sealing the tube and connecting a vacuum forming device; operating the vacuum forming device to create a negative pressure so that the internal pressure of the tube is equal to or less than the vapor pressure of the volatile material, thereby vaporizing the liquid volatile material; and filling the tube with an injected liquid by applying pressure. In the vaporizing step of the liquid volatile material, the negative pressure applied by the vacuum forming device expels air present inside the tube to the outside of the tube. In the filling step of the injected liquid, when the pressure applied inside the tube by filling reaches or exceeds the vapor pressure of the volatile material, condensation of the gaseous volatile material occurs, reducing the volume of the volatile material, and the injected liquid fills the space inside the tube formerly occupied by the gaseous volatile material.

Description

[Technical Field]

[0001] The present invention relates to a method for filling a liquid, more particularly to a method for filling a narrow tube or space with a closed end by injecting a liquid, and to an apparatus for carrying out such a method. [Background technology]

[0002] The technology of injecting a liquid into a narrow, closed-end channel or space is used in a variety of industrial fields. However, the injected liquid cannot be fully filled unless the air that previously occupied the space to be filled is removed or discharged to the outside. Even if the air trapped inside is compressed, the injected liquid cannot fill the volume of the compressed air. Furthermore, unlike in the case of a wide space, air trapped in a narrow, closed-end channel or space is more difficult to discharge during the filling process. This is because the surface tension of the injected liquid has a strong effect in a narrow channel, making it difficult for the trapped air to penetrate the liquid and be discharged to the outside (see Figure 1).

[0003] As the inventors have discovered, two prior art methods have been attempted to inject and fill a narrow, closed tube or space with a liquid. The first method involves creating an outlet for air evacuation in the closed space and then injecting the liquid while taking into account the loss of the injected material. This method not only results in material loss, but is also unsuitable for environments where an outlet for the space to be filled cannot be artificially created. The second method involves creating a high level of vacuum in the space to be filled. However, creating a pressure low enough to sufficiently remove the internal air is inefficient in terms of cost and difficulty. Furthermore, when a practically applicable vacuum is applied, the internal air is not sufficiently removed. For example, even if the internal pressure is reduced to 0.1 atmospheres, approximately 10% of the space is still occupied by air, and the space occupied by this air cannot be filled with the injected liquid. (Assuming air is an ideal gas, the formula PV = mRT can be applied, but mass is proportional to pressure when temperature and volume are the same.) Filling using a method of forming a high vacuum is only applicable in limited circumstances where the vapor pressure of the injected liquid is extremely low or the target filling rate is low. If the vapor pressure of the injected liquid is relatively high, the pressure inside the channel where the high vacuum is formed is lower than the vapor pressure of the injected liquid, which induces vaporization of the injected liquid. If the vacuum level is limited to be equal to or higher than the vapor pressure of the injected liquid to solve this problem, i.e., the problem of induced vaporization of the injected liquid, there is a limit to the low filling rate. Therefore, filling using a method of forming a high vacuum is only effective in limited circumstances where the vapor pressure of the injected liquid is extremely low or the target filling rate is low.

[0004] Thus, although there has always been a need in the related art for a technique capable of completely filling a narrow tube or space with one end blocked, no effective solution has emerged until the present invention. Summary of the Invention [Problem to be solved by the invention]

[0005] It is an object of the present invention to provide a method for filling a narrow tube or space with a liquid by injection, which achieves a significantly higher filling ratio than the prior art, or an apparatus for carrying out such a method.

[0006] It is also an object of the present invention to provide a method or apparatus for carrying out such a method which achieves significantly higher fill ratios than the prior art and which uses significantly simpler equipment and reduced costs than the prior art. [Means for solving the problem]

[0007] The present invention relates to a method for filling a narrow tube with a liquid and an apparatus for performing such a method. According to one embodiment of the present invention, a method for filling a narrow tube with a liquid includes the steps of injecting a volatile substance in a liquid state into the tube, sealing the tube and connecting a vacuum forming device, operating the vacuum forming device to create a negative pressure so that the internal pressure of the tube is equal to or less than the vapor pressure of the volatile substance, thereby vaporizing the volatile substance in the liquid state, and applying pressure to fill the tube with the injected liquid.

[0008] In the vaporization step of the liquid volatile material, the negative pressure applied by the vacuum forming device expels the air present inside the tube to the outside of the tube. In the filling step of the injection liquid, when the pressure applied inside the tube by filling reaches or exceeds the vapor pressure of the volatile material, condensation of the gaseous volatile material occurs, reducing the volume of the volatile material, and the injection liquid fills the space inside the tube formerly occupied by the gaseous volatile material.

[0009] The scope of the present invention also includes a liquid filling apparatus for carrying out the liquid filling method described above.

[0010] Furthermore, additional features may be included in the liquid filling method and apparatus for carrying out such method according to the present invention. [Effects of the Invention]

[0011] According to the present invention, a method or apparatus for carrying out such a method can be provided that achieves a significantly higher filling ratio than the prior art when injecting a liquid into a narrow tube or space with one end closed.

[0012] Furthermore, the present invention can provide a method or apparatus for carrying out such a method that achieves significantly higher filling ratios than the prior art, while using significantly simpler equipment and reduced costs than the prior art. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a diagram for explaining why air trapped in a narrow tube or space with a closed end is difficult to be discharged to the outside during the filling process of the injection liquid.

[0014] [Figure 2] 1 is a diagram illustrating a method for filling a liquid according to an embodiment of the present invention.

[0015] [Figure 3] 1 is a table listing the vapor pressures of various substances at room temperature.

[0016] [Figure 4] 1 is a diagram illustrating the results of an acetone vaporization experiment.

[0017] [Figure 5] 10 is a diagram illustrating the results of an experiment on injecting a filling material into acetone in a vaporized state.

[0018] [Figure 6] This is a diagram illustrating the results of a filling experiment using a plaster model made to resemble a tooth.

[0019] [Figure 7] 1 is a diagram illustrating the results of a filling experiment using an actual extracted tooth. DETAILED DESCRIPTION OF THE INVENTION

[0020] The following detailed description of the present invention refers to the accompanying drawings, which show, by way of example, specific embodiments in which the present invention may be practiced. These embodiments are described in detail to enable those skilled in the art to fully practice the present invention. It should be understood that the various embodiments of the present invention are different from one another but are not necessarily mutually exclusive. For example, specific shapes, structures, and characteristics described herein may be embodied in different embodiments without departing from the spirit and scope of the present invention. It should also be understood that the location or arrangement of individual components within each embodiment may be changed without departing from the spirit and scope of the present invention. Therefore, the following detailed description should not be taken in a limiting sense, and the scope of the present invention should be understood to encompass the scope of the appended claims and all equivalents thereof.

[0021] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, various preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily practice the present invention.

[0022]

[0023] [Basic principle of the present invention]

[0024] This invention utilizes the vaporization caused by boiling a volatile liquid and the condensation caused by compression as a method for efficiently removing air from the space to be filled. Generally, gas occupies approximately 1,000 times the volume of a liquid at the same weight. The space to be filled is filled with the vapor of the volatile liquid, rather than air, and then the injected liquid is filled. At the same time, the vapor of the volatile liquid is compressed and condensed to induce a phase change to a liquid state, which rapidly reduces the volume and ensures a high filling rate.

[0025]

[0026] [Description of the liquid filling method according to the present invention]

[0027] 2 is a diagram illustrating a method for filling a liquid according to an embodiment of the present invention, which will be described below with reference to FIG.

[0028] In the first step, a volatile liquid is injected into the space to be filled.

[0029] In the second step, the space is sealed and a vacuum forming device is connected.

[0030] In the third step, a vacuum is created so that the pressure is below the vapor pressure of the volatile liquid at room temperature (or the temperature of the relevant environment). Since it is sufficient to reduce the pressure below the vapor pressure, a high-level negative pressure generating device is not required.

[0031] In the fourth step, some of the air that filled the space while negative pressure was being created is expelled to the outside. As a result, the reduced pressure causes the volatile liquid to boil and evaporate. As the vacuum forming device operates, some of the air and vapor (vapor generated by the evaporation of the volatile liquid) inside the space is continuously expelled to the outside.

[0032] In the fifth stage, when the volatile liquid is completely vaporized while negative pressure is being created, most of the air occupying the space to be filled is expelled to the outside, and most of the space is filled with vapor of the volatile liquid.

[0033] In the sixth step, the injection liquid is filled in. The filling of the injection liquid compresses the vapor of the volatile liquid, increasing the pressure in the internal space.

[0034] In the seventh stage, when the pressure rises and exceeds the vapor pressure of the volatile liquid, condensation begins, and a phase change occurs in the liquid, with the volume reduced to 1 / 1000 of the volume of the vapor.

[0035] In the eighth stage, when the volatile liquid is completely condensed and filling is complete, only about 0.1% of the total space is filled with the volatile liquid, and the remaining space is filled with the injected liquid.

[0036] The theoretical background of the liquid filling method according to the embodiment of the present invention will now be described in detail.

[0037] First, we will explain why a volatile liquid is used in the present invention. For a liquid substance to boil and vaporize, the pressure of the surrounding environment at a specific temperature must drop below the vapor pressure, which is an inherent physical property of the substance, or the temperature of the surrounding environment at a specific pressure must rise above the boiling point, which is an inherent physical property of the substance. When a liquid vaporizes and becomes a gas, its volume generally increases by about 1,000 times. Conversely, when a gas liquefies and becomes a liquid, its volume decreases to 1 / 1,000th of its original size. Therefore, when the gas filling the space to be filled is compressed and condensed, the volume decreases rapidly, allowing the space to be filled without leaving any empty space.

[0038] It is advantageous to use a volatile liquid that can be easily vaporized and liquefied at room temperature and near normal pressure. Volatile liquids have a relatively low vapor pressure, and can be vaporized at room temperature even with a slight reduction in pressure, so they can be easily vaporized within the target space. Figure 3 is a table listing the vapor pressures of various substances at room temperature (for reference, 1 atmosphere is approximately 100 kPa).

[0039] Next, the principle of removing internal air will be explained. After a volatile liquid is injected into the space to be filled and vaporized by forming negative pressure, the internal space can be filled with the vapor of the volatile liquid. Most of the air that previously filled the space is discharged to the outside during the initial formation of negative pressure, and any remaining air can be continuously discharged along with some of the vapor generated by the vaporization of the volatile liquid. At this time, diffusion between the vapor of the volatile liquid and the air occurs rapidly, so the internal space can quickly become filled with the vapor of the volatile liquid. In particular, when the pressure is low due to the formation of negative pressure, diffusion between gases proceeds even more rapidly.

[0040] For example, typical gas-gas diffusion coefficients D1 at 1 atmosphere atm is as follows:

[0041] D1 atm ~10 -6-10 -5 m 2 / s

[0042] In an environment where a negative pressure of 0.1 atmospheres is created due to the evaporation of a volatile liquid, the diffusion coefficients of an ideal gas are D0.1. atm increases tenfold.

[0043] D0.1 atm ~10 -5 -10-4m 2 / s

[0044] If the depth of the space to be filled is set to L about 10 mm, the time t required for the vapor to diffuse is within a few seconds.

[0045] t~L2 / D0.1 atm ~100-10 1 s

[0046] Next, we will explain the appropriate negative pressure level. Quantitatively, the target pressure (P) in the internal space must satisfy the following conditions: P 揮発性液体 is the vapor pressure of the volatile liquid at ambient temperature.

[0047] P <P 揮発性液体

[0048] In this case, the type of volatile liquid (and vapor pressure) and the target pressure of the internal space can be determined dynamically depending on the vapor pressure characteristics of the injected liquid, the reactivity between the volatile liquid and the injected liquid, the compatibility of the volatile liquid with the target filling space, the ease of creating negative pressure in the target filling space, etc. For example, if acetone is used as the volatile liquid, the pressure in the internal space can be lowered to less than 0.3 atmospheres to allow acetone to boil and vaporize.

[0049]

[0050] [Experimental implementation using acetone as a volatile liquid]

[0051] The inventor(s) conducted an experiment to verify the liquid filling performance of the method according to the present invention described above into a narrow tube or space with one end blocked. In this experiment, acetone was used as a volatile liquid. Acetone has a vapor pressure of 30 kPa at 25°C and 48 kPa at 36°C.

[0052] The inventors conducted filling experiments in three different environments. In the first experiment, a transparent acrylic model was used so that the acetone evaporation process and filling process could be observed externally. In the second experiment, a plaster model made of a tooth was used. In the third experiment, an actual extracted tooth was used.

[0053] In all three experiments, liquid acetone was injected into the root canal of an acrylic tube, a plaster model, or an actual extracted tooth. Vaporization of the acetone was then induced through the creation of negative pressure, filling the narrow, sealed tube with acetone vapor. The filling material was then injected, and the increasing pressure during injection induced a phase change of the vaporized acetone to a liquid state, completing the filling.

[0054] The first experiment using the acrylic model was carried out in two stages: the first stage was an experiment in which acetone was vaporized, and the second stage was an experiment in which the filling material was injected into the vaporized acetone.

[0055] In the acetone evaporation experiment, the inventors created negative pressure in a 35-45°C water bath. The negative pressure level was gradually increased between 0 and 90 kPa to prevent direct inhalation of liquid acetone during the increase in negative pressure. Figure 4 illustrates the results of the acetone evaporation experiment. The left photograph in Figure 4 shows the state 2 seconds after negative pressure was applied to 40 μL of liquid acetone injected into a narrow, closed tube. The acetone begins to evaporate into small droplets. The middle photograph in Figure 4 shows the state 5 seconds after negative pressure was applied. The vaporized acetone occupies a larger space. The right photograph in Figure 5 shows the state 10 seconds after negative pressure was applied. The vaporized acetone occupies the entire narrow, closed tube. This experiment confirmed that acetone can be vaporized by creating negative pressure, that the air present in the tube can be almost completely expelled by creating negative pressure, and that the vaporized acetone can occupy the entire space. It also confirmed that approximately 10 seconds are required for 40 μL of acetone to evaporate and completely occupy the space. While this experiment demonstrated that 40 μL of acetone was used and that approximately 10 seconds are required for this amount of acetone to evaporate, these experimental results should not be construed as limiting the scope of the present invention. The amount of liquid acetone used can be varied depending on the size of the space to be filled, and the time required for liquid acetone to evaporate can also vary depending on the environment of the space. Furthermore, in addition to the method of creating negative pressure using a water bath, which was used in this experiment, any other method of creating negative pressure can be used. Of course, other volatile liquids besides acetone can also be used.

[0056] The results of the filler injection experiment with acetone vaporized are shown in Figure 5. The left photo in Figure 5 shows the state before the filler is injected, when acetone has completely vaporized and completely occupied the narrow, closed tube. The middle photo in Figure 5 shows the intermediate stage of the filler injection process under the same conditions. In the middle photo in Figure 5, the opaque filler has been injected and occupies more than two-thirds of the top of the tube, but has not yet reached the bottom of the tube. The right photo in Figure 5 shows the completed state, with the filler almost completely reaching the bottom of the closed, narrow tube. Theoretically, acetone that has changed into a liquid state rather than the filler is present at the bottom of the tube. However, because the volume occupied by liquid acetone is only 1 / 1000 of the total tube volume, it appears to the naked eye that the filler has completely occupied the entire tube.

[0057] Figure 6 shows the results of a filling experiment using a plaster cast made of a tooth. The inventors used two control groups in the filling experiment using the dental plaster cast. The first control group was a condition in which negative pressure was created but liquid acetone was not injected, and therefore acetone vaporization did not occur, corresponding to the left side of Figure 6. The second control group was a condition in which liquid acetone was injected, and then the same negative pressure was applied to vaporize the acetone before injecting the filling material, corresponding to the right side of Figure 6. The filling pressure was 150 kPa in both control groups. Referring to Figure 6, it can be seen that in the first control group, the increasingly narrow canals formed in the dental plaster cast were only half-filled. In contrast, in the second control group, where acetone was injected and the filling material was injected in the vaporized state, it can be seen that the same canals were completely filled. In the control group shown in Figure 6, the ends of the canals were completely sealed.

[0058] Figure 7 illustrates the results of a filling experiment using actual extracted teeth. The inventors used three control groups in this experiment. The first group was a condition in which no negative pressure was applied and no acetone was injected or vaporized, corresponding to the left side of Figure 7. The second group was a condition in which negative pressure was applied but no acetone was injected or vaporized, corresponding to the middle side of Figure 7. The third group was a condition in which acetone was injected and vaporized under the same negative pressure as the second control group, and then the filling material was injected, corresponding to the right side of Figure 7. The filling pressure was 150 kPa in all three control groups. Referring to Figure 7, the control group, which used the filling method of the present invention, showed overwhelmingly superior filling performance.

[0059]

[0060] Although the present invention has been described above using specific details such as specific components and limited examples and drawings, this is merely provided to facilitate a more general understanding of the present invention, and the present invention is not limited to the above examples. Those skilled in the art to which the present invention pertains may attempt various modifications and changes from such descriptions.

[0061] Therefore, the concept of the present invention should not be limited to the above-described embodiments, and all scopes equivalent to or modified equivalently from the scope of the claims below, as well as the scope of the invention, can be said to fall within the scope of the concept of the present invention.

Claims

1. A method for filling a narrow tube with a liquid, the method comprising: injecting a volatile substance in a liquid state into the tube; sealing the tube and connecting a vacuum forming device; activating the vacuum forming device to form a negative pressure in the tube so that the internal pressure is equal to or less than the vapor pressure of the volatile substance, thereby vaporizing the liquid volatile substance; applying pressure to fill with injection liquid; In the vaporization step of the liquid volatile substance, the air existing inside the tube is expelled to the outside of the tube by the negative pressure created by the vacuum forming device, In the step of filling the pipe with the injection liquid, when the pressure applied to the inside of the pipe by filling reaches or exceeds the vapor pressure of the volatile substance, condensation of the gaseous volatile substance occurs, reducing the volume of the volatile substance, and the space inside the pipe formerly occupied by the gaseous volatile substance is filled with the injection liquid, a liquid filling method.

2. 2. The liquid filling method of claim 1, wherein the volatile substance is acetone.

3. A method for filling a root canal, comprising: injecting a volatile substance in a liquid state into the root canal; sealing the upper end of the root canal and connecting a vacuum forming device; activating the vacuum forming device to form a negative pressure so that the pressure inside the root canal is equal to or less than the vapor pressure of the volatile substance, thereby vaporizing the liquid volatile substance; applying pressure to pack the packing material; In the vaporization step of the liquid volatile substance, the air existing inside the tube is expelled to the outside of the tube by the negative pressure created by the vacuum forming device, A root canal filling method in which, in the filling step, when the pressure applied to the canal by filling reaches or exceeds the vapor pressure of the volatile substance, condensation of the gaseous volatile substance occurs, reducing the volume of the volatile substance, and the space within the canal formerly occupied by the gaseous volatile substance is filled with the filling material.

4. 4. The method of claim 3, wherein the volatile substance is acetone.

5. A liquid filling apparatus for carrying out the method of claim 1.

6. 6. The liquid filling apparatus of claim 5, wherein the volatile substance is acetone.

7. Root canal filling device for carrying out the method according to claim 3.

8. 8. The root canal filling device of claim 7, wherein the volatile substance is acetone.

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