CN210533934U - Drop surface tension testing device - Google Patents
Drop surface tension testing device Download PDFInfo
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- CN210533934U CN210533934U CN201921133399.5U CN201921133399U CN210533934U CN 210533934 U CN210533934 U CN 210533934U CN 201921133399 U CN201921133399 U CN 201921133399U CN 210533934 U CN210533934 U CN 210533934U
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- 238000012360 testing method Methods 0.000 title claims abstract description 10
- 239000007788 liquid Substances 0.000 claims abstract description 101
- 239000002184 metal Substances 0.000 claims abstract description 48
- 238000000034 method Methods 0.000 claims description 12
- 238000003384 imaging method Methods 0.000 claims description 6
- 238000004804 winding Methods 0.000 claims description 4
- 239000000463 material Substances 0.000 abstract description 2
- 238000012827 research and development Methods 0.000 abstract description 2
- 238000005259 measurement Methods 0.000 description 7
- 230000005484 gravity Effects 0.000 description 3
- 229920000642 polymer Polymers 0.000 description 3
- 238000004616 Pyrometry Methods 0.000 description 2
- 230000001133 acceleration Effects 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 238000005070 sampling Methods 0.000 description 2
- 238000012935 Averaging Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010191 image analysis Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 239000006060 molten glass Substances 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000004611 spectroscopical analysis Methods 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- 230000004584 weight gain Effects 0.000 description 1
- 235000019786 weight gain Nutrition 0.000 description 1
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Abstract
The utility model relates to the new material research and development field, a liquid drop surface tension testing device, which comprises a rotary motor, a rotary disk, a support table, two fixed rods, a camera, a light source, a computer, a metal ring, a liquid drop to be tested, a current source, a cable and an electric brush, wherein the rotary motor can be adjusted in speed, the rotary disk comprises a front surface, a back surface and a side surface, a circle on the side surface is provided with two annular electrodes which are respectively connected with the positive electrode and the negative electrode of the current source through the cable and the electric brush, the rotary motor is coaxially connected with the back surface of the rotary disk, the support table is fixed at the edge of the front surface of the rotary disk, the rotary motor drives the rotary disk to rotate in an xy plane, the two fixed rods are parallelly arranged on the support table and are parallel to the rotary disk, the metal ring absorbs the liquid drop to be detected, and the current source can supply current to the metal ring, so that the metal ring generates heat and the liquid drop to be detected is heated.
Description
Technical Field
The utility model belongs to the technical field of new material research and development and specifically relates to a can accurate definite liquid droplet surface tension's a liquid droplet surface tension testing arrangement.
Background
The surface tension of liquid can reflect certain characteristics of the liquid and has important significance in scientific research and engineering application, and the most common method for measuring the surface tension of the liquid is a Wilhelmy method which determines the surface tension of the liquid by measuring the weight gain of a sheet in contact with the surface of the liquid and has the defect that the measurement of the liquid with high surface tension is time-consuming; the surface tension of liquids is usually measured by a spectroscopic method and a laser interference manipulation method, for example, a suspended droplet method is used to measure the surface tension of a relatively small amount of liquid, and the surface tension of the liquid surface is determined by the distortion of the shape of the droplet, but the surface tension of some liquids can only be measured at a relatively low level, and particularly, the surface tension of liquids with high surface tension, high viscosity and high temperature, such as molten metal, molten glass, high molecular polymer, and the like, cannot be measured with high precision.
SUMMERY OF THE UTILITY MODEL
In order to solve the above problem, the utility model relates to a device for measuring liquid surface tension is based on rotatory measuring method, is applicable to high surface tension and high liquid of viscosity.
The utility model adopts the technical proposal that:
the liquid drop surface tension testing device comprises a rotary motor, a rotary disk, a supporting platform, two fixing rods, a camera, a light source, a computer, a metal ring, a liquid drop to be tested, a current source, a cable and an electric brush, wherein xyz is a three-dimensional coordinate system, the rotary motor can be adjusted in speed, the rotary disk is a disk and comprises a front surface, a rear surface and a side surface, two annular electrodes are arranged on the periphery of the side surface, the two annular electrodes are respectively connected with the anode and the cathode of the current source through the cable and the electric brush, the rear surface of the rotary disk is coaxially connected with the rotary motor, the supporting platform is fixed at the edge of the front surface of the rotary disk, the rotary motor can drive the rotary disk to rotate in an xy plane, the two fixing rods are mutually and parallelly arranged on the supporting platform, the two fixing rods are parallel to the rotary disk, the two fixing rods are, the metal ring is formed by winding a metal bifilar wire with the diameter of 0.2 mm, liquid drops to be detected are adsorbed in the metal ring, and a current source can supply current to the metal ring, so that the metal ring generates heat and the liquid drops to be detected are heated; the camera, the light source and the computer are all positioned on one side of the front surface of the rotating disc, and the camera and the light source are all connected with the computer through cables, so that the camera can image the metal ring and the liquid drop to be detected on the supporting table and input imaging information into the computer; the radius of the rotating disc is 30 mm; the diameter of the metal ring is 1.3 mm.
The method for measuring the surface tension of the liquid drop by adopting the liquid drop surface tension testing device comprises the following steps:
step one, transferring 5 microliters of liquid to be detected into a metal ring by using a laboratory pipettor to form liquid drops to be detected, wherein the density rho of the liquid to be detected is known;
adjusting the position of a camera to enable the camera to image the metal ring and the liquid drop to be detected;
step three, starting the rotary motor to enable the rotary disc to rotate around the central axis of the rotary disc in the xy plane, so that the liquid drop to be detected rotates around the central axis of the rotary disc in the xy plane, and the rotating speed of the rotary motor is omega0；
Step four, the camera collects imaging information of the liquid drop to be detected and inputs the imaging information into the computer, the imaging information of the liquid drop to be detected when the liquid drop to be detected is positioned at the lowest side of the rotating disc in each rotating period is selected and analyzed, and the average curvature and the change of the surface of the liquid drop to be detected are obtained by analyzing the imaging information;
step five, adjusting the rotating speed of the rotating motor, wherein the rotating speed of the rotating motor is omega0、1.2ω0、1.5ω0、1.8ω0And 2.0. omega0Repeating the third step and the fourth step under the condition of (1);
step six, obtaining the change rate delta H/H of the average curvature of the surface of the liquid drop to be detected under different rotating speed values of the rotary motor according to the step five, wherein the delta H represents the difference value of the average curvatures of any two points with height difference H on the liquid drop to be detected;
step seven, drawing the data in the step six into a graph, wherein the ordinate is the change rate delta H/H of the average curvature of the surface of the liquid drop to be detected, and the abscissa is the acceleration g of the liquid drop to be detected respectively measured under the conditions of different rotating speeds of the rotating disk/Product g of h/And h, performing linear fitting, wherein the fitting value of the slope is rho/2 sigma, and finally calculating to obtain the surface tension sigma of the liquid drop to be measured.
The utility model has the advantages that:
the utility model discloses the device can carry out surface tension to high surface tension or high viscosity liquid and measure, and measurement accuracy is higher, and is with low costs, and it is little to measure required sample dosage to can be used for measuring the heating liquid drop.
Drawings
The following is further illustrated in connection with the figures of the present invention:
FIG. 1 is a schematic view of the present invention;
FIG. 2 is a schematic front view of the rotating disk;
fig. 3 is an enlarged schematic top view of the metal ring.
In the figure, 1 is a rotary motor, 2 is a rotary disk, 3 is a support table, 4 is two fixed rods, 5 is a camera, 6 is a light source, 7 is a computer, 8 is a metal ring, and 9 is a liquid drop to be detected.
Detailed Description
FIG. 1 is a schematic view of the present invention, which comprises a rotary motor (1), a rotary disk (2), a support table (3), two fixing rods (4), a camera (5), a light source (6), a computer (7), a metal ring (8), a liquid drop (9) to be measured, a current source, a cable and a brush, where xyz is a three-dimensional coordinate system, the rotary motor (1) can adjust speed, the rotary disk (2) is a disk and comprises a front surface, a rear surface and a side surface, a circle of the side surface has two ring electrodes, the two ring electrodes are respectively connected with the positive electrode and the negative electrode of the current source through the cable and the brush, the rear surface of the rotary disk (2) is coaxially connected to the rotary motor (1), the support table (3) is fixed at the edge of the front surface of the rotary disk (2), the rotary motor (1) can drive the rotary disk (2) to rotate in an xy plane, and the camera (5), the camera (5) and the light source (6) are both connected with the computer (7) through cables, so that the camera (5) can image the metal ring (8) on the support table (3) and the liquid drop (9) to be detected, and the imaged information is input into the computer (7).
As shown in fig. 2, which is a schematic front view of a rotating disk, in the figure, at the moment when a droplet (9) to be measured is located at the lowest side of the rotating disk (2) in one rotation period, the radius of the rotating disk (2) is 30 mm, two fixing rods (4) are installed on a supporting platform (3) in parallel, the two fixing rods (4) are parallel to the rotating disk (2), the two fixing rods (4) are respectively conducted with two annular electrodes on the side surface of the rotating disk (2) through the supporting platform (3), two ends of a metal ring (8) are respectively connected and conducted with the upper ends of the two fixing rods (4), the droplet (9) to be measured is adsorbed in the metal ring (8), the typical size of the diameter of the droplet (9) to be measured is 1 mm, and a current source can supply current to the metal ring (8), so that the metal ring (8) generates heat and heats.
As shown in fig. 3, which is an enlarged schematic top view of the metal ring, the metal ring (8) is formed by winding a metal bifilar with a diameter of 0.2 mm, and the diameter of the metal ring (8) is 1.3 mm.
Principle of rotating droplets to measure surface tension: when the surface tension of the liquid drop is measured by adopting a traditional liquid drop hanging method, 2 sigma delta H-rho gh is provided according to a Populus-Laplace equation, wherein sigma represents the surface tension of the liquid drop to be measured, delta H represents the difference value of the average curvatures of any two points with height difference H on the liquid drop to be measured, rho represents the liquid density of the liquid drop to be measured, a real-time image of the liquid drop to be measured is analyzed, 10 points on the surface of the liquid drop to be measured are selected as sampling points, the curvatures of the sampling points are obtained through image analysis, and finally the surface tension of the liquid drop to be measured is obtained. The equation shows that the increase of Δ H or ρ gh can improve the accuracy of the surface tension measurement of the liquid drop, and when the size of the liquid drop to be measured is large enough and the surface tension is low, the liquid drop is gradually deformed and finally drops under the action of its gravity, in this case, the surface tension can be measured more accurately, but for the liquid with high surface tension, the measurement accuracy of the existing method is low, and in the device of the present application, the liquid drop to be measured is rotated in the vertical plane, the distortion deformation of the liquid drop to be measured is enhanced under the combined action of the centrifugal force and the gravity, and when the viscosity of the liquid is low enough and the liquid drop is deformed within one rotation, the above equation of young-laplace can be expressed as 2 σ Δ H ρ (ω ═ ρ (ω ═ ω (ω H) ("g — H2L +/-g) h, wherein omega and L are respectively the rotating speed and the rotating radius of the liquid drop to be measured rotating around the central shaft of the rotating disc (2), and when the liquid drop to be measured is positioned at the bottom and the top of the rotating disc (2), a positive sign and a negative sign are respectively applied, wherein h is less than one thousandth of L.
If the viscosity of the liquid drop to be measured is high enough and the characteristic time constant of the deformation of the liquid drop is more than one thousand times larger than the rotation period of the rotating disc (2), the action of gravity can be ignored, and the Yang-Laplace equation can be expressed as 2 sigma delta H ═ rho omega2Lh, for the liquid drop to be measured with smaller size, the viscous force can overcome the inertia, the characteristic time constant of the movement is similar to R η/sigma, wherein R is the radius of the liquid drop to be measured, η is the viscosity of the liquid drop to be measured, and when omega > sigma/R η, 2 sigma delta H ═ rho omega can be obtained2Lh is approximately true, for example, for a droplet to be measured with a surface tension σ of 0.1 n/m, if the radius R of the droplet to be measured is 1 mm and the viscosity η is 1000 pascal · s, the rotation speed ω of the droplet to be measured rotating around the central axis of the rotating disk (2) needs to be greater than 100 times/s, and the rotating motor (1) is a dc motor or a variable frequency adjustable speed motor.
Explanation of the specific measurement method: the shape of the liquid drop (9) to be detected is detected by the camera (5) at a certain moment in the rotation cycle of the liquid drop (9), for example, when the liquid drop (9) to be detected rotates to the lowest side of the rotating disk (2), whether the liquid drop (9) to be detected is in an equilibrium state is judged through the change of the shape of the liquid drop (9) to be detected. The key point of measurement is that the average curvature of the liquid drop (9) to be measured is determined by observing the shape of the liquid drop, because the liquid drop (9) to be measured rotates and can only be observed from one direction, therefore, the average curvature can only be obtained by averaging two main curvatures, the utility model discloses a structure of a fixed rod (4) and a metal ring (8), the shape of the liquid drop (9) to be measured is symmetrical by the limitation of the geometric boundary of the metal ring (8), and the plane of the metal ring (8) is vertical to the direction of the centrifugal force received when the liquid drop (9) to be measured rotates around the central shaft of the rotating disk (2); moreover, can be to becket (8) circular telegram for its heat production is and is heaied up to adsorbing the liquid drop (9) that awaits measuring in becket (8), and especially better to the temperature control ability of small-size liquid drop, consequently, the utility model discloses can be used for carrying out the pyrometry to glass and high-molecular polymer etc. like melting.
The diameter of the typical size of the liquid drop (9) to be measured is 1 mm, and the liquid drop shape is stable in the rotation process of only tens of seconds, which is much shorter than the measurement time of the traditional suspension method.The same liquid drop (9) to be detected is measured by changing the rotating speed of the liquid drop (9) to be detected to obtain different degrees of distortion deformation, namely more accurate surface tension can be obtained through multiple measurements, a graph is drawn by fitting measured data, the ordinate is the change rate delta H/H of the average curvature of the surface of the liquid drop (9) to be detected, and the abscissa is the acceleration g of the liquid drop (9) to be detected respectively measured under different rotating speed conditions of the rotating disk (2)/Product g of h/H, according to equation 2 σ Δ H ═ ρ (ω) of2L + -g) h, the fitted value for the slope is expressed as ρ/2 σ.
The liquid drop surface tension testing device comprises a rotary motor (1), a rotary disk (2), a support table (3), two fixing rods (4), a camera (5), a light source (6), a computer (7), a metal ring (8), liquid drops (9) to be tested, a current source, a cable and an electric brush, wherein xyz is a three-dimensional coordinate system, the rotary motor (1) can regulate speed, the rotary disk (2) is a disk and comprises a front surface, a rear surface and a side surface, two annular electrodes are arranged on the periphery of the side surface, the two annular electrodes are respectively connected with the positive electrode and the negative electrode of the current source through the cable and the electric brush, the rear surface of the rotary disk (2) is coaxially connected with the rotary motor (1), the support table (3) is fixed on the edge of the front surface of the rotary disk (2), the rotary motor (1) can drive the rotary disk (2) to rotate in an xy plane, the two fixing rods (4) are parallel to the rotating disc (2), the two fixing rods (4) are respectively communicated with two annular electrodes on the side face of the rotating disc (2) through the supporting table (3), two ends of the metal ring (8) are respectively connected with and communicated with the upper ends of the two fixing rods (4), the metal ring (8) is formed by winding metal twin wires with the diameter of 0.2 mm, liquid drops (9) to be detected are adsorbed in the metal ring (8), and the current source can supply current to the metal ring (8), so that the metal ring (8) generates heat and the liquid drops (9) to be detected are heated; the camera (5), the light source (6) and the computer (7) are all located on one side of the front face of the rotating disc (2), and the camera (5) and the light source (6) are all connected with the computer (7) through cables, so that the camera (5) can image a metal ring (8) and a liquid drop (9) to be detected on the supporting table (3), and image information is input into the computer (7); the radius of the rotating disc (2) is 30 mm; the diameter of the metal ring (8) is 1.3 mm.
The utility model discloses the device adopts the method of rotatory liquid drop to measure liquid surface tension, is applicable to high surface tension and high-viscosity liquid, measures required liquid sample dosage at microlitre magnitude, and has the heating function, can carry out pyrometry to glass and high polymer etc. that melt.
Claims (3)
1. A liquid drop surface tension testing device comprises a rotary motor (1), a rotary disk (2), a supporting table (3), two fixing rods (4), a camera (5), a light source (6), a computer (7), a metal ring (8), liquid drops to be tested (9), a current source, a cable and an electric brush, wherein xyz is a three-dimensional coordinate system, the rotary motor (1) can adjust the speed, the rotary disk (2) is a disk and comprises a front surface, a rear surface and a side surface, two annular electrodes are arranged on the periphery of the side surface, the two annular electrodes are respectively connected with the positive electrode and the negative electrode of the current source through the cable and the electric brush,
the method is characterized in that: the rear surface of the rotating disk (2) is coaxially connected with a rotating motor (1), a supporting table (3) is fixed at the edge of the front surface of the rotating disk (2), the rotating motor (1) can drive the rotating disk (2) to rotate in an xy plane, two fixing rods (4) are arranged on the supporting table (3) in parallel, the two fixing rods (4) are parallel to the rotating disc (2), the two fixing rods (4) are respectively communicated with two annular electrodes on the side face of the rotating disc (2) through the supporting table (3), two ends of the metal ring (8) are respectively connected with and communicated with the upper ends of the two fixing rods (4), the metal ring (8) is formed by winding metal twin wires with the diameter of 0.2 mm, liquid drops (9) to be detected are adsorbed in the metal ring (8), and the current source can supply current to the metal ring (8), so that the metal ring (8) generates heat and the liquid drops (9) to be detected are heated; the camera (5), the light source (6) and the computer (7) are all located on one side of the front face of the rotating disc (2), the camera (5) and the light source (6) are all connected with the computer (7) through cables, so that the camera (5) can image the metal ring (8) and the liquid drop (9) to be detected on the supporting table (3), and imaging information is input into the computer (7).
2. A droplet surface tension testing apparatus as claimed in claim 1, wherein: the radius of the rotating disc (2) is 30 mm.
3. A droplet surface tension testing apparatus as claimed in claim 1, wherein: the diameter of the metal ring (8) is 1.3 mm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921133399.5U CN210533934U (en) | 2019-07-10 | 2019-07-10 | Drop surface tension testing device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921133399.5U CN210533934U (en) | 2019-07-10 | 2019-07-10 | Drop surface tension testing device |
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| Publication Number | Publication Date |
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| CN210533934U true CN210533934U (en) | 2020-05-15 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201921133399.5U Withdrawn - After Issue CN210533934U (en) | 2019-07-10 | 2019-07-10 | Drop surface tension testing device |
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| CN (1) | CN210533934U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110376103A (en) * | 2019-07-10 | 2019-10-25 | 金华职业技术学院 | A kind of Surface Tension of Liquid Drops test device |
-
2019
- 2019-07-10 CN CN201921133399.5U patent/CN210533934U/en not_active Withdrawn - After Issue
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110376103A (en) * | 2019-07-10 | 2019-10-25 | 金华职业技术学院 | A kind of Surface Tension of Liquid Drops test device |
| CN110376103B (en) * | 2019-07-10 | 2024-04-09 | 金华职业技术学院 | Liquid drop surface tension testing device |
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Granted publication date: 20200515 Effective date of abandoning: 20240409 |
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| AV01 | Patent right actively abandoned |
Granted publication date: 20200515 Effective date of abandoning: 20240409 |