JP2017219388A - Surface tension measuring device and surface tension measuring method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure a surface tension of various liquid under a high pressure.SOLUTION: A surface tension measuring device 10 includes a container 11 for storing liquid L which is a measuring object in the sealed state, a passage 12 arranged inside the container 11 so that one end is positioned in the liquid L in the container 11, and that the other end is positioned on the furthermore upper side than a liquid level LA in the container 11, and lifting by a surface tension, the liquid L flowing inside from one end, and liquid level detection means 14 for detecting the liquid level LA in the container 11 and a liquid level LB in the passage 12.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a surface tension measuring device and a surface tension measuring method, for example, a surface tension measuring device capable of measuring a liquefied gas liquefied under high pressure, a mixture of a liquefied gas and a liquid, and a surface tension. It relates to a measurement method.

  Conventionally, lubricating oil is used in various fields, for example, in a refrigerator, sometimes in an atmosphere of a high-pressure refrigerant. In the refrigerator, the lubricating oil circulates in the refrigeration cycle with the refrigerant dissolved therein. The lubricating oil in which the refrigerant is dissolved (that is, the mixture of the refrigerant and the lubricating oil) may change its physical properties when the amount of the refrigerant is large, and may affect the performance of the lubricating oil or the refrigerator. Therefore, it is desired to check the physical properties of lubricating oils, particularly lubricating oils for refrigerators, under the actual pressure and atmosphere used. For example, lubricating oils that have been conventionally placed under high-pressure refrigerants. A viscosity measurement method for measuring the kinematic viscosity is established (see Patent Documents 1 to 3).

JP-A-3-48134 Japanese Patent Laid-Open No. 10-142139 JP 2007-108045 A

However, physical properties that affect the performance of lubricating oil and refrigerators are not limited to kinematic viscosity. For example, check how the surface tension of a mixture of refrigerant and lubricating oil affects refrigeration performance and lubricating performance. The need has arisen.
This invention is made | formed in view of the above situation, and the subject of this invention is various liquids under high pressure, for example, liquefied gas, such as a refrigerant | coolant liquefied under high pressure, or a mixture of liquefied gas and liquid, etc. An object is to measure the surface tension.

As a result of intensive studies, the present invention has found that the above problems can be solved by a surface tension measuring device having a predetermined configuration and a surface tension measuring method using the surface tension measuring device, and the following invention has been completed. . That is, the present invention provides the following surface tension measuring device.
A container for storing a liquid to be measured in a sealed state, and disposed inside the container such that one end is located inside the liquid inside the container and the other end is located above the liquid level inside the container; A surface tension measuring device comprising: a channel that raises the liquid flowing into the inside from the one end by surface tension; a liquid level inside the container; and a liquid level detecting unit that detects the liquid level inside the channel.
Furthermore, the present invention provides the following surface tension measurement method.
The liquid to be measured is filled inside the container in a sealed state, and flows into the container so that one end is located inside the liquid inside the container and the other end is located above the liquid level inside the container. A path is arranged, the liquid flowing into the inside from the one end is raised by surface tension, the liquid level inside the container and the liquid level inside the flow path are detected at least, and the surface tension of the liquid is measured Surface tension measurement method.

  According to the present invention, it is possible to measure the surface tension of various liquids such as liquefied gas or a mixture of liquefied gas and liquid under high pressure.

It is a front view of the surface tension measuring device of a 1st embodiment. It is a side view of the surface tension measuring device of a 1st embodiment. In 1st Embodiment, it is a longitudinal cross-sectional view of the holder holding a capillary inside. It is an arrow cross-sectional view which follows the IV-IV line in FIG. In 1st Embodiment, it is a disassembled perspective view of the holder holding a capillary tube. It is a chart which shows an example of the relational expression of temperature, solubility, and surface tension. It is a graph which shows an example of a calibration curve. It is a schematic diagram of the surface tension measuring apparatus of 2nd Embodiment. It is a top view which shows an upper holding part and a lower holding part. It is a top view which shows the capillary tube arrange | positioned in bundle shape. It is a perspective view which shows the capillary which consists of a pipe | tube and a columnar member. It is a perspective view which shows an example of the slit member which consists of two slit formation parts. It is a perspective view which shows another example of the slit member which consists of two slit formation parts. It is a perspective view which shows an example of the slit member which consists of a some plate-shaped member. It is a perspective view which shows another example of the slit member which consists of a some plate-shaped member. It is a perspective view which shows the example of the slit member in which a slit is formed with a groove | channel.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 and 2 are schematic views of the surface tension measuring device 10 according to the first embodiment of the present invention as viewed from the front side and the side. However, in FIG. 2, the holder is indicated by a dotted line for the sake of simplicity of explanation.
The surface tension measuring device 10 includes a container 11 that contains a liquid L to be measured in a sealed state, one end positioned inside the liquid L inside the container 10, and the other end positioned above the liquid level LA inside the container 11. In this way, the flow path 12 that is arranged inside the container 11 and raises the liquid L flowing into the inside from one end by the surface tension, the liquid level LA inside the container 11, and the liquid level LB inside the flow path 12 are detected. And a liquid level detecting means 14 for performing. In addition, an atmospheric gas G exists above the liquid L in the container 11.

The container 11 is a transparent hermetic container formed in an elongated tubular shape. The container 11 may be a glass tube or a sapphire tube. Here, when the container 11 is a glass tube, the preferable working pressure range is 0-3 MPa. Moreover, when the container 11 is a sapphire tube, the preferable working pressure range is 0-20 MPa. The container 11 is preferably a sapphire tube so that it can be used even under high pressure. Moreover, as sapphire, it is more preferable that it is single crystal sapphire.
While the lower end of the container 11 is closed, an opening that can be sealed with a lid 18 is provided at the upper end. An introduction pipe 17 for introducing the liquid L and the atmospheric gas G into the inside of the container 11 is inserted through the lid 18. Although not shown, the introduction pipe 17 is provided with a check device such as a check valve to prevent the atmospheric gas G from leaking to the outside.

  In the present embodiment, the member constituting the flow path 12 is a capillary tube 13. The capillary tube 13 is preferably made of glass. The capillary tube 13 (flow channel) is open at both ends, and one end 13X is located inside the liquid L and the other end 13Y is located above the liquid level LA. The shape of the capillary tube of this embodiment is a cylindrical shape. Since the capillary is cylindrical, a measurement error is reduced, and the capillary 13 can be easily manufactured. The inner diameter of the capillary 13 is not particularly limited, but is preferably 0.05 to 1 mm, and more preferably 0.08 to 0.5 mm so that the capillary phenomenon sufficiently occurs. Moreover, although the height (length of a flow path) of the capillary 13 is not specifically limited, It is preferable that it is 5-50 cm, and it is more preferable that it is 8-20 cm. Furthermore, the outer diameter of the capillary tube 13 is preferably 0.2 to 2 mm, and more preferably 0.3 to 1 mm.

In the present embodiment, a plurality of capillaries 13 are arranged inside the container 11. In the present embodiment, the plurality of capillaries 13 are arranged in a line in a line. Moreover, the capillary tube 13 is arrange | positioned so that the longitudinal direction may follow a perpendicular direction. The capillary tube 13 is preferably parallel to the vertical direction, but may be slightly inclined with respect to the vertical direction. However, when the capillaries 13 are tilted, the tilt angles of the capillaries 13 should be the same. The inclination angle when the capillary is inclined is preferably less than 5 degrees, more preferably less than 3 degrees.
Further, the diameters of the plurality of capillaries 13 are the same. Therefore, the liquid level LB inside the capillary 13 rises due to the capillary phenomenon, but the height of the liquid level inside each capillary 13 is the same. The number of capillaries 13 is not particularly limited and may be one or more, but is preferably 2 to 15, more preferably 3 to 10.

  The plurality of capillaries 13 are held by the holder 20, and the holder 20 that holds the capillaries 13 is disposed inside the container 11. The holder 20 of the present embodiment extends vertically and has an elongated shape, like the capillary tube 13, and one end 13 </ b> X of the capillary tube 13 is formed by the lower end side of the holder 20, and the other end 13 </ b> Y of the capillary tube 13 is formed by the upper end side. Is retained. In addition, the capillary tube 13 is hold | maintained by the holder 20 by arrange | positioning inside the holding hole provided in the holder 20 so that it may mention later. In order to detect the liquid level LB inside the capillary tube 13, the holder 20 is provided with observation windows 23 and 24 each having an opening (see FIGS. 3 and 5).

In the present embodiment, a liquid level detection sensor disposed outside the container 11 is used as the liquid level detection means 14. A liquid level detection sensor that can move up and down is used. Specifically, as shown in FIG. 2, the liquid level detection means 14 includes a first liquid level detection sensor 15 having a first light emitting unit 15A and a first light receiving unit 15B, and a second light emitting unit. 16A and a second liquid level detection sensor 16 having a second light receiving unit 16B.
The first light-emitting unit 15A and the first light-receiving unit 15B can move up and down synchronously so that the light emitted by the first light-emitting unit 15A is received by the first light-receiving unit 15B. Is. Further, the first light emitting unit 15A emits light so that light passes through the inside of the container 11 without irradiating the holder 20 and the capillary tube 13 with light. Then, the first light emitting unit 15A and the first light receiving unit 15B are moved up and down in synchronization, the light reception is blocked by the liquid L inside the container 11, and the first light receiving unit 15B removes the light from the first light emitting unit 15A. The position at which the light cannot be received or the amount of light is reduced is detected as the liquid level LA inside the container 11.

  The second light emitting unit 16A and the second light receiving unit 16B can be moved up and down synchronously so that the light emitted by the second light emitting unit 16A is received by the second light receiving unit 16B. Is. The second light emitting unit 16 </ b> A emits light so that light passes through the observation windows 23 and 24 of the holder 20. Then, the second light-emitting unit 16A and the second light-receiving unit 16B are moved up and down in synchronization, and the received light is shielded by the liquid L inside the capillary tube 13, and the second light-receiving unit 16B removes the light from the second light-emitting unit 16A. Is detected as the liquid level LB inside the capillary tube 13.

In the present embodiment, the width of the optical path in the capillary tube 13 of the light emitted from the second light emitting unit 16 </ b> A is equal to or less than the total width of the plurality of capillary tubes 13. By being below the total width, the light from the light emitting part is easily shielded completely by the liquid inside the capillary tube 13, so that the liquid level LB inside the capillary tube 13 can be easily detected. In the present embodiment, as is apparent from FIGS. 1 and 2, the plurality of capillaries 13 are arranged in a plurality of rows in the lateral direction with respect to the traveling direction of the light emitted from the second light emitting unit 16A. Therefore, the total width (length along the horizontal direction) of the capillary tube 13 is increased, and is easily set to be larger than the optical path width.
The first and second light emitting units 15A and 16A are not particularly limited, but optical fibers, photodiodes, and the like are used. Similarly, the first and second light receiving portions 15B and 16B are not particularly limited, but an optical fiber, a photo sensor, or the like is used.

Although not shown, the surface tension measuring device 10 includes pressure detection means for detecting the pressure inside the container 11. An example of the pressure detection means is a pressure gauge attached to the introduction pipe 17.
The surface tension measuring device 10 further includes a thermostatic chamber 40 that houses the container 11 therein. The thermostatic chamber 40 is filled with a heat medium 41 made of a liquid such as water. The thermostat 40 is provided with temperature adjusting means 42 in order to keep the heat medium 41 at a predetermined temperature. Although not shown, the temperature adjusting means 42 includes a heating device and a cooling device, a temperature sensor that detects the temperature of the heat medium 41, and a controller that controls the heating device and the cooling device based on the temperature detected by the temperature sensor. Prepare. The temperature inside the container 11 (that is, the temperature of the liquid L and the atmospheric gas G) can be maintained at a constant temperature by the thermostatic bath 40.
The temperature inside the container 11 becomes substantially the same as the temperature of the thermostat 40 by leaving the container 11 inside the thermostat 40 for a sufficient time. Therefore, it is possible to detect the temperature inside the container 11 (that is, the temperature of the liquid L and the atmospheric gas G) by the temperature sensor provided in the thermostat 40. However, in order to detect a more accurate temperature, it is preferable to provide temperature detection means such as a temperature sensor inside the container 11.

The liquid L inside the container 11 is a gas at normal temperature and normal pressure, but preferably contains a liquefied gas that liquefies under pressure. The liquefied gas alone or the liquefied gas and a liquid that is liquid at normal temperature and normal pressure. It is preferable that it is a mixture. Moreover, it is preferable that the atmospheric gas G consists of gaseous liquefied gas.
Specifically, it is preferable that the container 11 is filled with lubricating oil and a refrigerant. A part of the refrigerant exists in the container 11 in a gaseous state, and a part of the refrigerant is dissolved in the lubricating oil. preferable. That is, it is preferable that the liquid L placed in the container 11 is a mixture of lubricating oil and a refrigerant, and the atmospheric gas G is a refrigerant that is not dissolved in the lubricating oil. Examples of the lubricating oil include various synthetic oils, mineral oils, mixtures thereof, and oils to which various additives are added. Examples of the refrigerant include natural refrigerants represented by fluorocarbons such as fluorinated hydrocarbons and hydrocarbons such as carbon dioxide, ammonia and propane.

  3 and 4 are a longitudinal sectional view and a transverse sectional view, respectively, of a holder for holding a capillary tube therein. FIG. 5 is an exploded perspective view of the holder 20. The holder 20 includes first and second holding portions 21 and 22. The first and second holding portions 21 and 22 hold the capillary 13 sandwiched from the front and rear. As is apparent from FIGS. 3 and 5, the first and second holding portions 21 and 22 have an elongated shape like the holder 20, and the first and second holding portions 21 and 22 are Each holder (hereinafter also referred to as contact surfaces 21A and 22A) is brought into contact with each other to form the holder 20.

The first and second holding portions 21 and 22 are provided with observation windows 23 and 24 at positions corresponding to the middle portion 13Z of the capillary tube 13, respectively. The midway portion 13Z is a portion between the one end 13Z and the other end 13Y of the capillary tube 13. As a result, the observation windows 23 and 24 are provided at positions corresponding to the liquid level LB inside the capillary tube 13, so that the liquid level LB can be detected by the liquid level detection means 14 as described above.
The observation windows 23 and 24 are openings that extend in the longitudinal direction of the holder 20. The openings (observation windows 23 and 24) penetrate from the contact surfaces 21A and 22A of the first and second holding portions 21 and 22 to the opposite surfaces 21B and 22B, which are the surfaces opposite to the contact surfaces. To do.

  The contact surface 21A of the first holding part 21 is provided with a lower groove 25 and an upper groove 26 connected to the lower end and the upper end of the observation window (that is, opening) 23, respectively. The lower groove 25 and the upper groove 26 are grooves for arranging and holding one ends 13X and 13Y of the capillary tube 13 therein. Each of the lower groove 25 and the upper groove 26 has the contact surfaces 22A of the second holding portion 22 in contact with the contact surfaces 21A of the first holding portion 21 so that the ends 13X and 13Y of the capillary 13 are connected. A holding hole for holding inside is formed. In each of the lower groove 25 and the upper groove 26, the vertical movement of the capillary tube 13 is restricted by a lower end surface 25D and an upper end surface 26U described later. Note that the contact surface 22A of the second holding portion 22 is flat and has no groove.

More specifically, the lower groove 25 is connected to the lower end of the observation window 23, and is connected to the lower holding groove 25A for disposing the one end 13X of the capillary tube 13 inside and the lower holding groove 25A. A portion 25B and a lower opening groove 25C that is connected further below the connection portion 25B and opens at the lower surface 21D of the first holding portion 21 are provided. The height of the bottom of the connecting portion 25B is higher than the height of the lower holding groove 25A and the lower opening groove 25C. With such a structure, the lower end surface 25D of the lower holding groove 25A is configured by the step between the lower holding groove 25A and the connecting portion 25B. Then, one end 13X of the capillary tube 13 disposed inside the holding groove 25A is placed on the lower end surface 25D, and the downward movement of the capillary tube 13 (that is, the downward movement) is restricted.
Furthermore, communication holes 29A and 29B are provided on both sides of the lower end portion of the lower holding groove 25A. The communication holes 29 </ b> A and 29 </ b> B are through holes that penetrate toward the opposite surface 21 </ b> B of the first holding portion 21.
The liquid L in the container 11 passes through the lower opening groove 25C, the gap between the connection portion 25B and the contact surface 22A of the second holding portion 22, and the communication holes 29A and 29B, and the lower holding groove 25A. In addition, it enters the inside of the capillary tube 13.

The upper groove 26 is connected to the upper end of the observation window 23, and includes an upper holding groove 26A for arranging the other end 13Y of the capillary tube 13 inside, and an upper opening groove 26B connected to the upper side of the upper holding groove 26A. Prepare. The upper opening groove 26 </ b> B has a groove bottom that is higher than the upper holding groove 26 </ b> A and opens on the upper surface 21 </ b> U of the first holding portion 21. With such a structure, the step between the upper opening groove 26B and the upper holding groove 26A becomes the upper end face 26U of the upper holding groove 26A, and the upper end face 26U restricts the upward movement of the capillary tube 13. Further, the upper opening groove 26 </ b> B is provided to prevent the other end 13 </ b> Y of the capillary 13 from being blocked by the holder 20.
Since the size of the lower holding groove 25A and the upper holding groove 26A (that is, the holding hole) is the same size as the plurality of capillaries 13 arranged in a row, the capillaries 13 are front-rear and left-right within the holder 20. Movement is also restricted.

The distance from the upper end surface 26U to the lower end surface 25D is substantially equal to the length of the capillary tube 13 or slightly longer than the length of the capillary tube 13. Therefore, each of the one end 13X and the other end 13Y of the capillary tube 13 can be disposed inside the lower holding groove 25A and the upper holding groove 26A.
As shown in FIG. 5, screw holes 31 and 32 are provided at the four corners of the first and second holding portions 21 and 22, respectively, and the screw holes 31 and 32 at the four corners are arranged at positions that coincide with each other. The The first and second holding portions 21 and 22 are fixed to each other with the contact surfaces 21A and 22A in contact with each other by screws 33 screwed into the screw holes 31 and 32.

Next, a method for measuring the surface tension using the surface tension measuring device 10 will be described.
In this measurement method, first, the capillary tube 13 (flow path 12) is arranged inside the container 11, and the liquid L is filled inside the container, and the container is sealed.
Specifically, for example, the holder 20 holding the capillary 13 inside the container 11 may be disposed, and then the container 11 may be sealed by filling the liquid L and the atmospheric gas G into the container 11.
The filling method of the liquid and the atmospheric gas is not particularly limited, but when filling a liquid such as lubricating oil and a liquefied gas such as a refrigerant, the container 11 that has been evacuated may be filled with a mixture of the liquid and liquefied gas. Or after putting a liquid thing into the container 11 and evacuating the inside of the container 11, you may enclose liquefied gas in the container 11. Thus, when filling a liquid substance and liquefied gas separately, it is better to vibrate the container 11 etc. and to mix a liquid substance and liquefied gas in the container 11 inside.
In this measurement method, the inside of the container 11 is pressurized. By applying pressure, the surface tension of the liquefied gas or the mixture of the liquid and the liquefied gas can be measured. The pressure is preferably 1 to 20 MPa, more preferably 3 to 15 MPa.

  Inside the container 11, the capillary tube 13 is arranged so that one end 13X is located inside the liquid L and the other end 13Y is located above the liquid level LA. Therefore, the liquid flowing into the capillary 13 from the one end 13X is Increased by capillary action (ie surface tension). And the liquid level difference arises between the liquid level LA inside the container 11 and the liquid level LB inside the capillary tube 13. In this measurement method, the liquid level detecting means 14 detects the liquid level LA inside the container 11 and the liquid level 13A inside the capillary tube 13 and measures the length of the liquid level difference to determine the surface tension of the liquid L. Ask.

  In this measurement method, the liquid level difference caused by the liquid L to be measured should be set to a certain level or more by adjusting the size of the inner diameter of the capillary tube 13 in order to accurately measure the surface tension. . Specifically, the liquid level difference is preferably 2 mm or more, more preferably 5 to 150 mm.

In order to obtain the surface tension from the liquid level difference, it is preferable to create a calibration curve for the surface tension and the liquid level difference in advance for two or more types of substances having a known surface tension, or obtain a function representing the calibration curve. . Then, the surface tension may be calculated from the liquid level difference based on a calibration curve or a function. The calibration curve is usually represented by a linear function.
If one calibration curve or function is prepared for the same surface tension device, one of the calibration curves or functions can be used regardless of the temperature and pressure inside the container 11 when measuring the surface tension of the liquid L to be measured. The surface tension can be calculated from the liquid level difference using a calibration curve. However, a calibration curve or a function is made for every constant temperature (for example, every 10 ° C.) or every constant pressure (for example, every 1 atm), and at the time of liquid level difference measurement caused by the liquid L to be measured. The surface tension may be calculated using a calibration curve or function of temperature and pressure that matches or approximates the temperature and pressure in the container.

Further, when the container 11 is filled with a liquid material such as lubricating oil and a liquefied gas such as a refrigerant, the surface tension measuring device 10 can also calculate the solubility of the liquefied gas in the liquid material. Specifically, first, the volume (Vg) of the atmospheric gas G inside the container 11 at the measurement temperature is calculated by detecting the liquid levels LA and LB. Further, the density (d) of the atmospheric gas G is obtained from the pressure inside the container 11. Then, using the volume (Vg), density (d), and the mass (Wo) of the liquid material filled in the container 11 and the mass (Wr) of the liquefied gas, the following formula is used to express the liquefied gas liquid. It is possible to calculate the solubility (Xr).
Xr = (Wr−dVg) / (Wo + Wr−dVg)

  Even in a mixture of the same type of liquefied gas and the same type of liquid material, the surface tension differs if the solubility (that is, the mixing ratio) is different. Therefore, for example, in a mixture of the same type of liquefied gas and the same type of liquid, by changing the pressure inside the container to change the solubility and measuring the surface tension for each solubility, for example, the solubility and surface in the mixture It is also possible to obtain a relational expression of tension. By such an aspect, it becomes easy to confirm how the surface tension of the mixture of the refrigerant and the lubricating oil affects the refrigeration performance and the lubrication performance in the refrigerator.

  Furthermore, the surface tension is measured by filling the liquid L to be detected in the container 11 and changing the temperature inside the container 11 within a certain temperature range (for example, 20 to 80 ° C.) For example, the surface tension may be measured every 10 ° C. According to this method, the relationship between the surface tension and the temperature can be expressed by a function. In this case as well, the pressure and solubility may be measured as described above in accordance with the measurement of the surface tension.

Furthermore, in this embodiment, when measuring the surface tension of the mixture of the liquefied gas and the liquid, by recording the temperature and pressure together, parameters such as pressure, temperature, solubility and the surface tension It is also possible to obtain a relational expression (correlation). This makes it possible to calculate the solubility and surface tension of the liquid at a specific temperature and pressure by calculation.
As an example of the relational expression, the relational expression between the temperature and the surface tension when the solubility is constant is as shown in FIG. In FIG. 6, only one relational expression is shown in the chart, but usually, measurement is performed by changing the solubility, and a plurality of different relational expressions are created for each solubility.

Next, an example of a method for creating a calibration curve will be described more specifically.
In this method, first, two or more standard materials having known surface tensions are prepared. In this example, water, polyalkylene glycol (PAG), mineral oil, and refrigerant (R-410A) are used as standard substances. Each standard substance is filled in the container 11 of the surface tension measuring device 10, and after the container 11 is sealed, the inside is adjusted to a predetermined temperature (for example, 20 ° C.). At this time, as shown in FIGS. 1 and 2, the capillary 13 held by the holder 20 is disposed inside the container 11.

In addition, when the standard substance is a substance that is liquid at normal temperature and normal pressure, the inside of the sealed container 11 may be set to normal pressure or pressurized, but normal pressure is preferable. At this time, the atmospheric gas may be a gas that does not substantially dissolve in the liquid standard substance, and may be nitrogen or the like.
On the other hand, when the standard substance filled in is a liquefied gas (refrigerant) that is a gas at normal temperature and normal pressure, the inside of the container 11 is pressurized so that at least a part of the standard substance becomes liquid. To. In this case, the atmospheric gas may be made of a gaseous liquefied gas.

  Inside the container 11, the liquid (standard substance) that has entered the capillary 13 from one end 13 </ b> X of the capillary 13 rises due to capillary action. Therefore, the difference between the liquid level inside the capillary and the liquid level inside the container is detected by the liquid level detection means 14, and a calibration curve is created based on the detection result and the known surface tension. The calibration curve may be created by a known method such as a least square method. Table 1 shows an example of data on the known surface tension of each standard substance and the detected liquid level difference at a predetermined temperature (20 ° C.). FIG. 7 shows a calibration curve obtained from the data in Table 1.

  If the calibration curve shown in FIG. 7 is used, the surface tension value of the liquid L to be measured is calculated from the liquid level difference detected when the liquid L to be measured is filled into the container 12 as indicated by the arrow line. It is possible to read.

  As described above, according to the present embodiment, it is possible to measure the surface tension of a liquid under high pressure. Therefore, it becomes possible to measure the surface tension of the liquefied gas liquefied under high pressure or the mixture of the liquefied gas and the liquid. Moreover, it becomes easy to measure surface tension correctly by using a capillary tube. Furthermore, by arranging a plurality of capillaries, the liquid level inside the capillary can be easily detected by the liquid level detecting means.

  Next, a second embodiment of the present invention will be described with reference to FIGS. In the second embodiment, the shape of the holder for holding the capillary tube is different. Hereinafter, the second embodiment will be described with respect to differences from the first embodiment, and other descriptions will be omitted. In FIG. 8 and subsequent figures, members having the same configuration as in the first embodiment are denoted by the same reference numerals. In the second embodiment, an example in which the number of capillaries constituting the flow path is one will be described with reference to the drawings.

In the surface tension measuring device 45 of the present embodiment, the holder 50 for holding the capillary tube 13 includes a lower holding part 51 arranged on the lower end side of the container 11 and an upper holding part 52 arranged on the upper end side of the container 11. Consists of The lower holding part 51 and the upper holding part 52 are made of an elastic member such as rubber, for example, and are press-fitted into the container 11 and fixed at an arbitrary position on the inner peripheral surface of the container 11. The lower holding portion 51 and the upper holding portion 52 are provided with through holding holes 51A and 52A, respectively. The lower holding part 51 is usually arranged below the liquid level LA inside the container 11. The capillary tube 13 is disposed so as to pass through the through-holding holes 51 </ b> A and 52 </ b> A, whereby the capillary tube 13 is held by the holder 50 at one end 13 </ b> X and the other end 13 </ b> Y side.
The diameters of the through-holding holes 51A and 52A are larger than the outer diameter of the capillary tube 13. Therefore, the capillary tube 13 can easily pass through the through-holding holes 51A and 52A. The diameters of the through-holding holes 51A and 52A are preferably 1.1 to 5 times the outer diameter of the capillary tube 13 and more preferably 1.5 to 3.5 times.

  In the present embodiment, the liquid level LB inside the capillary 13 is adjusted so as to be positioned between the lower holding part 51 and the lower holding part 52, and the liquid level LB inside the capillary 13 can be detected by the liquid level detection means 14. It is. Accordingly, in this embodiment as well, as in the first embodiment, the surface tension can be measured by measuring the length of the liquid level difference between the liquid level LB and the liquid level LA by the liquid level detecting means 14. is there.

The present invention has been specifically described with reference to the embodiments. However, the present invention is not limited to these embodiments, and various improvements and design changes can be made without departing from the gist of the present invention. is there.
Specifically, the capillaries may be singular or plural in any aspect. For example, as shown in FIGS. 1 to 5, in the case where the holder includes first and second holding portions that sandwich and hold the capillary tube from the front and the back, the capillary tube may be single. Further, as in the second embodiment, in the case where the holder includes a lower holding part and an upper holding part for holding one end side and the other end side of the capillary tube, a plurality of capillaries may be provided. Further, the holder may be omitted as long as the capillary tube can be stably disposed inside the container.

Moreover, when there are a plurality of capillaries, the capillaries 13 are not limited to a mode in which the capillaries are arranged in a line, but may be arranged in other modes, for example, in a bundle shape as shown in FIG. . By arranging in a bundle, the total width is increased as in the case where a plurality of lines are arranged in a line, so that the liquid level inside the capillary tube 13 can be easily detected. The number of capillaries 13 arranged in a bundle is not limited as long as it is three or more, but 3 to 30 is preferable. When the capillary 13 is in a bundle shape, the shape of the holder is not particularly limited, but as shown in the second embodiment, the holder holds a lower holding portion and an upper holding portion for holding one end side and the other end side of the capillary tube. It is better to have a part. By using the lower holding part and the upper holding part shown in the second embodiment, the bundled capillaries can be easily held by the holder.
The plurality of capillaries 13 in a bundle shape may be integrated by bonding with an adhesive or the like. For example, the bundled capillaries 13 that are integrated into a bundle can be easily erected inside the container, so that it is easy to omit the holder. Of course, the plurality of capillaries 13 may be integrated by bonding with an adhesive other than when bundled.

The capillary tube may have a cylindrical shape other than the cylindrical shape shown in the first and second embodiments. Specifically, it may be a polygonal cylindrical shape such as a rectangular cylindrical shape, an elliptical cylindrical shape, a semicircular shape, or the like. Further, as shown in FIG. 11, the capillary 63 may have a configuration in which a columnar member 65 is arranged inside a cylindrical tube 64. That is, the flow path constituted by the capillary tube may have an annular cross section. In this case, as shown in FIG. 11, it is preferable that the pipe 64 is cylindrical, the columnar member 65 is columnar, and the flow path is circular in cross section, but may have other shapes. For example, the tube 64 may be a polygonal cylinder such as a rectangular cylinder or may be an elliptic cylinder. Similarly, the columnar member 65 may be a polygonal column such as a quadrangular column, or an elliptical column. If the shape is other than a circular cross-section or an annular shape, the liquid level does not become horizontal, but the average height of the liquid level may be calculated.
When the flow path has an annular cross section, the length D along the radial direction of the flow path is preferably 0.05 to 1 mm, and more preferably 0.08 to 0.5 mm. Further, the outer diameter and inner diameter of the pipe 64 are preferably 0.5 to 15 mm and 0.4 to 10 mm, respectively, and more preferably 1 to 10 mm and 0.7 to 7 m. The outer diameter of the columnar member 65 is preferably 0.35 to 9.5 mm, more preferably 0.6 to 6 mm.
The shape and size of the capillary are not limited to the above configuration, and the liquid rises in the capillary due to the capillary phenomenon utilizing surface tension, and as described above, the liquid level inside the capillary and the inside of the container There is no particular limitation as long as the shape and size of the capillary tube can read the liquid level difference.

  Further, the shape of the holder is not limited to the above-described shape, and may be various forms. For example, in the first embodiment, the lower groove and the upper groove are provided only in the first holding portion, but the lower groove and the upper portion similar to the first holding portion are provided in the second holding portion. A groove may be provided. In addition, for example, the holder is not limited to two members such as the first and second holding units, the upper holding unit, and the lower holding unit, and may be formed of one member. For example, it is good also as a structure which inserts a capillary in the holding part which consists of one member by which the holding hole was formed previously.

  Further, the liquid level detecting means 14 is not limited to the above-described one, and may be an optical type using light, and a sensor of a type different from the above type may be used. For example, the first and second light emitting units for detecting the liquid levels LA and LB may be one light emitting unit, and the first and second light receiving units may be one light receiving unit. Moreover, you may use the sensor of systems other than an optical type. Further, when it is not necessary to measure the solubility, the pressure detection means may be omitted. Furthermore, as long as the temperature inside the container 11 (that is, the temperature of the liquid L and the atmospheric gas G) can be made constant, the thermostatic chamber 40 may be omitted.

  In the above description, the member constituting the flow path is a capillary. However, the member may be constituted by a member other than the capillary. Specifically, you may comprise by the slit member which has one or more slits which make a flow path. In addition, a slit means the flow path formed between a pair of surfaces arrange | positioned mutually close so that a liquid can raise the inside by surface tension. The pair of surfaces that form the slits are provided along the vertical direction and are arranged in parallel to each other. As in the case of a capillary tube, one end of the flow path formed by the slit may be positioned inside the liquid inside the container, and the other end may be positioned above the liquid level inside the container.

  Specific examples of the slit member are shown in FIGS. A slit member 70 shown in FIGS. 12 and 13 has two slit forming portions 71 and 71 arranged to face each other, and a slit 73 is formed between the slit forming portions 71 and 71. The slit forming portions 71 and 71 are both long in the vertical direction, and form one end 73 </ b> X and the other end 73 </ b> Y of the flow path constituted by the slit 73 between the upper end and the lower end, respectively. The slit forming portions 71 and 71 may be plate-like members as shown in FIG. 12, semi-cylindrical members as shown in FIG. 13, or other shapes. Good.

  Furthermore, as shown in FIGS. 14 and 15, a slit member 80 formed by bonding a plurality of plate-like members 81 may be used. In this case, at least one plate-like member 81 has a recessed portion 82 at the side edge portion of the bonding surface 81A with the other plate-shaped member 81, and a slit 83 is formed by the recessed portion 82. In FIG. 14, the recessed portion 82 is provided on one side edge portion, but may be provided on both side edge portions as shown in FIG. A plurality of slits 83 are formed in one slit member 80 by providing the recessed portions 82 on both side edges. In addition, as shown in FIG. 15, a plurality of slits 83 can be formed in one slit member 80 by bonding three or more plate-like members 81 together. One end 83X and the other end 83Y of the flow path constituted by the slits 83 are configured by the lower end and the upper end of the plate member 81.

  Further, as shown in FIG. 16, the slit may be constituted by a groove 92 provided in the slit member 90. As shown in FIG. 16, two or more grooves 92 may be provided, but may be one. The groove 92 is engraved from the side surface of the slit member 90, and both ends 92X and 92Y open at the lower end surface and the upper end surface of the slit member 90, respectively, and constitute one end and the other end of the flow path, respectively.

  Even when the flow path is constituted by a slit, the shape of the slit is preferably such that the liquid level difference between the liquid level inside the container and the liquid level inside the slit is 2 mm or more, more preferably 3 to 150 mm. And the size may be selected. For example, the interval W between the slits is preferably 0.05 to 0.5 mm, and more preferably 0.08 to 0.3 mm mm. In addition, when a some slit is provided in a container, the space | interval W of a slit becomes the mutually same so that the height of the liquid level in a slit may become the same. In addition, the height of each slit (that is, the length of the flow path) is preferably 5 to 50 cm, and more preferably 8 to 20 cm.

Similarly to the first and second embodiments, the slit member may be arranged in the container while being held by the holder, or may be arranged inside the container without being held by the holder. For example, when the slit member shown in FIG. 11 is used, the holder has, for example, a fitting groove provided on the bottom surface and the inner peripheral surface of the container, and a side end portion of the slit forming portion 71, The lower end portion may be fitted into the fitting groove.
When the slit member is used as the member forming the flow path, the other aspects are the same as in the case of the capillary tube, and the surface tension is measured by measuring the liquid level difference between the liquid level inside the container and the liquid level inside the slit. The solubility can also be measured.

DESCRIPTION OF SYMBOLS 10, 45 Surface tension measuring device 11 Container 12 Flow path 13, 63 Capillary tube 13X, 73X, 83X One end 13Y, 73Y, 83Y The other end 13Z Middle part 14 Liquid level detection means 15 1st liquid level detection sensor 16 2nd liquid Surface detection sensor 20, 50 Holder 21 First holding part 22 Second holding part 23, 24 Observation window 25 Lower groove 26 Upper groove 40 Thermostatic chamber 51 Lower holding part 52 Upper holding part 70, 80, 90 Slit member 73, 83 Slit 82 Recessed part 92 Groove G Atmospheric gas L Liquid LA, LB Liquid surface W Slit spacing

Claims (12)

A container for storing a liquid to be measured in a sealed state;
The liquid that has been placed inside the container so that one end is inside the liquid inside the container and the other end is located above the liquid level inside the container, and the liquid that has flowed into the inside from the one end by surface tension. A channel to be raised,
A surface tension measuring device comprising: a liquid level inside the container; and a liquid level detecting means for detecting a liquid level inside the flow path.   The surface tension measuring device according to claim 1, wherein the flow path is configured by a capillary tube or a slit member.   The surface tension measuring device according to claim 1 or 2, wherein a plurality of capillaries are arranged inside the container.   The surface tension measuring device according to claim 2 or 3, wherein a holder holding the capillary or the slit member is disposed inside the container. The flow path is constituted by a capillary tube,
The surface tension measuring device according to claim 4, wherein the holder includes first and second holding portions, and the capillary is sandwiched and held by the first and second holding portions from the front and rear.   The surface tension measuring device according to claim 5, wherein each of the first and second holding portions includes an observation window at a position corresponding to a liquid level inside the flow path.   7. The surface according to claim 6, wherein the first holding part includes a lower groove and an upper groove that are respectively connected to an upper end and a lower end of the observation window and in which one end and the other end of the capillary tube are respectively disposed. Tension measuring device. The flow path is constituted by a capillary tube,
The holder is fixed to the inner peripheral surface of the container, and includes a lower holding part and an upper holding part arranged on the lower end side and the upper end side of the container,
The surface tension measuring device according to claim 4, wherein each of the lower holding part and the upper holding part holds one end side and the other end side of the capillary tube.   The surface tension measuring device according to any one of claims 1 to 8, further comprising pressure detecting means for detecting a pressure inside the container.   The surface tension measuring device according to any one of claims 1 to 9, further comprising temperature detecting means for detecting a temperature inside the container.   The surface tension measuring device according to any one of claims 1 to 10, further comprising a thermostatic chamber that houses the container therein. The liquid to be measured is filled inside the container in a sealed state, and flows into the container so that one end is located inside the liquid inside the container and the other end is located above the liquid level inside the container. Arranging a path, raising the liquid flowing into the inside from the one end by surface tension,
A surface tension measurement method for measuring a surface tension of the liquid by detecting at least a liquid level inside the container and a liquid level inside the flow path.

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