CN117054295A - Device and method for testing dynamic surface tension by bubble pressure method - Google Patents
Device and method for testing dynamic surface tension by bubble pressure method Download PDFInfo
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- 229920002379 silicone rubber Polymers 0.000 claims abstract description 16
- 238000003860 storage Methods 0.000 claims abstract description 16
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- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 3
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- G—PHYSICS
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- G01N13/02—Investigating surface tension of liquids
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N13/00—Investigating surface or boundary effects, e.g. wetting power; Investigating diffusion effects; Analysing materials by determining surface, boundary, or diffusion effects
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Abstract
The invention discloses a device and a method for testing dynamic surface tension by a bubble pressure method, and belongs to the technical field of interfacial chemical measurement. The device comprises a pressure sensor, an air pump, a control unit, a flow sensor, a needle head, a gas processing unit and a tee joint, wherein one interface of the tee joint is connected with an exhaust throttle valve, and the other interface is communicated with the air pump. According to the invention, the three-way valve, the exhaust throttle valve, the air storage cavity pressing plate and the silicon rubber decompression film are added at the air input end, and the problems that the surface tension of the existing bubble pressure method is easily influenced by bubble operation pulses, is influenced by the extra pressure of an air pump, the calculation of the dynamic surface tension time is inaccurate, the balance surface tension of the surfactant in the bubble pressure method cannot be obtained through testing and the like are effectively solved, so that a more reliable and accurate dynamic surface tension change curve and balance value are obtained.
Description
Technical Field
The invention relates to a device and a method for testing dynamic surface tension by a bubble pressure method, and belongs to the technical field of interfacial chemical measurement.
Background
Surface tension is an inherent physicochemical property of a substance. Methods for measuring the surface tension include a platinum Plate method (Wilhelmy Plate) and a platinum Ring method (DuNouy Ring), an image analysis method (drop off method, hanging drop method and rotating drop method) of the ADSA algorithm (ADSA), a capillary height method, a pressure method and a volume method, and the like. Different test methods can achieve different test purposes. One particular test requirement in surface tension, particularly liquid surface tension applications, is the measurement of surfactants. The surface tension of surfactants is usually expressed as dynamic due to the adsorption time effect specific to surfactants (Dynamic surface tension). In the existing method, if a new liquid-gas or liquid-liquid interface cannot be formed on the surface of the surfactant, the method cannot realize dynamic surface tension measurement of the already formulated surfactant solution (Dynamic Surface tension). Such as weighing principle or spin drop method, capillary rise method, etc. While the drop-off method or the hanging drop method can control the drop speed to form one drop (expanding or contracting drop), the volumetric method can also control the drop speed of dripping, and thus the dynamic surface tension can be tested. However, these methods are susceptible to additional forces in droplet or bubble formation when testing dynamic surface tension, resulting in a significant reduction in test time accuracy.
The bubble pressure method is a classical test method for dynamic surface tension. Currently there are many commercially available bubble pressure surface tensioners, including german multi-family company (Lauda, sita, sinterface, kruss), shanghai mid-morning company, and the like. These commercial bubble pressure surface tensioners all feature a controllable flow air pump, throttle valve, pressure sensor, capillary tube and control unit. Among them, lauda provides a flow rate reading unit made of a micro pressure sensor, which controls flow rate through PID program. The drawbacks of these methods are: 1. the equilibrium surface tension of the surfactant cannot be tested and obtained, and only the dynamic surface tension change trend curve can be tested; 2. the additional pressure value of the air pump can only be corrected by software, and the influence of the additional pressure on the surface tension result can not be fundamentally solved from hardware, so that the dynamic surface tension measurement result and the time effect analysis are also influenced; 3. the time of the dynamic surface tension is calculated according to the pressure and the flowmeter and is not consistent with the time of the actual dynamic surface tension; 4. the effect of the pulses during operation of the diaphragm pump or peristaltic pump on the dynamic surface tension time and the surface tension value cannot be eliminated.
In the prior International patent, 1 and Kruss company patent Blastdruckteniometer (patent number: EP 1 464 948 A1) propose an improved throttle valve and an improved method for producing a usable throttle valve, and the influence of different immersion depths on hydrostatic pressure is eliminated by means of the throttle valve. In the throttle, this patent provides a thin film damping for eliminating gas pressure fluctuations; meanwhile, a throttling circuit board and a manufacturing mode of the circuit board are provided so as to achieve the purpose of throttling. The patent simply lists the air path structure and innovates the damping film described above, while other parts such as a throttle valve and the like are prior art. The patent provides narrow 26 air channels and 32 air channels in the air channel design, and a capillary tube with a very small inner diameter, so that the problem to be solved by the patent is not solved in the core design technology, and the problem comprises: (1) The excessive capillary is too thin to effectively test the hydrostatic pressure by the pressure sensor, rather than solving the problem that the immersion depth affects the hydrostatic pressure as described in the patent; (2) The influence of the additional pressure on the surface tension and the dynamic surface tension cannot be solved, and can only be realized by software correction. In the design, from a wide or thick gas path to a narrow or thin gas path, when the pressure sensor is positioned in the wide gas path, the problems of high gas flow speed and high pressure and low gas flow speed and low pressure occur. Such pressure variation with the magnitude of the air flow is the basic principle of testing dynamic surface tension. The gas path design as described above may result in failure to confirm whether the pressure change caused by dynamic changes in the surfactant or the pressure change caused by changes in the gas flow. (3) Only when the apparent reduction flow rate is slow, the effect does not appear to be influenced, and the time effect of the pulse in the operation of the diaphragm pump on the surface tension and the dynamic surface tension cannot be practically solved. 2. The Sita company patent DEVICE FOR DYNAMIC MEASUREMENT OF THE SURFACE TENSION OF A LIQUID (patent number: U.S. Pat. No. 6,185,989 Bl) proposes a portable bubble pressure surface tensiometer, which is characterized in that besides a conventional pressure sensor and a temperature sensor, the core technology of the Sita company patent is a specially designed nozzle, and the Sita company patent is characterized in that the nozzle 6 has a very long length relative to a nozzle opening, the nozzle is positioned on the lower bottom surface of a tested liquid, and the direction of bubbles and buoyancy are blown from bottom to top in the same direction rather than more common from top to bottom, and then the bubbles float. This design method of calculating surface tension is not consistent with the conventional method of maximum bubble pressure, the former is hanging drop and the latter is stopping drop. 3. The Sita company patent HANDHELD TENSIOMETER FEATURING AUTOMATIC REGULATION OF THE BUBBLE LIFE BY MEASURING AND REGULATING THE GAS VOLUME FLOW (patent number: U.S. Pat. No. 8,161,802 B2) proposes a special gas-liquid regulating valve (14) and a differential pressure gauge (13) parallel to the throttle valve for calculating and controlling the gas flow rate, and thus for more rapid and accurate control of the gas flow rate. This technique has been widely adopted in Lauda bubble pressure method instruments, belongs to the prior art, and since the flow rate sensing device has a difference between the flow rate at the input front end and the flow rate at the rear end, there is a significant in-out in the time of calculating the dynamic surface tension. 4. Patent METH OD AND DEVICE FOR MEASURING TH E SURFACE TENSION OF LIQUID (US 2007/0277597 Al) proposes to test pressure and convert it to surface tension using inexpensive acoustic pressure transducers. At the same time, the patent similarly proposes common system components comprising a gas source, a pressure sensor or a sound pressure transducer, a throttle valve and a capillary tube.
In chinese patent, a dynamic surface tension measuring device (CN 01216543), a method and device for measuring surface tension of liquid (CN 200680005570), a device for measuring surface tension of liquid by maximum bubble method (CN 201320755842), a liquid surface tension measuring device (CN 201420119091), a device for measuring surface tension of high-temperature melt by maximum bubble method (CN 201610655866), a device for measuring surface tension by maximum bubble pressure method (CN 201920614800) are all simple descriptions of a common pressure sensor and a device for measuring surface tension by bubble pressure method such as an air pump and an air pipe, and the like, and the problems mentioned above cannot be solved in practical application.
Miller & L.LIggieri, bubble and drop Interfaces (published by VPS Press 2011), describes the dynamic surface tension of the bubble pressure process in Chapter 5, maximum bubble pressure tensiometry:thory, analysis of Experimental Constrains and Applications (pages 75-118), and reviews the overall development of the bubble pressure process. However, since no special hardware modification is performed on the pump operation pulse and the additional pressure in the design principle of the apparatus, there are many defects in practical application. Such as: 1. the pressure values of the bubble pressure method designed by the method are obviously excessively far from the standard value. According to the bubble pressure method surface tension calculation formula (page 80), and using an author capillary radius of 0.085mm, calculated as a surface tension of 72mN/m, the pressure value is 1694Pa, and the actual pressure value is 1820Pa at maximum (page 79). 2. The dynamic surface tension time is calculated according to the pressure value and the flow value, and is not directly tested according to the pressure curve. The authors give the dead time (td) at page 85 as: td=32×η/[ r0×ps-PH) ] [1/3×rb/r0 ] 3+γ/(r0×ps-PH) (rb/r 0)/(2) ] while td=tb×l/(kp×p) (1+3/2×r0/rb.
How to effectively provide a dynamic surface tension meter with higher precision and fewer affected factors based on a bubble pressure method, and an instrument and a method for providing more effective dynamic surface tension of a surfactant for industries such as chemical industry, materials, electronics, semiconductors, cosmetics, pesticides, coatings and the like are the problems to be solved in the field of interfacial chemical measurement.
Disclosure of Invention
The technical problems to be solved by the invention are as follows: the device and the method for testing the dynamic surface tension of the bubble pressure method solve the problems that the surface tension of the existing bubble pressure method is easily influenced by bubble operation pulses, is influenced by additional pressure of an air pump, the dynamic surface tension time is inaccurate in calculation, the balance surface tension of a surfactant in the bubble pressure method cannot be tested, and the like, so that a more reliable and accurate dynamic surface tension change curve and a balance value are obtained.
The technical problems to be solved by the invention are realized by adopting the following technical scheme:
the device for testing the dynamic surface tension of the bubble pressure method comprises a pressure sensor, an air pump, a control unit, a flow sensor, a needle head, a gas processing unit and a gas processing unit, wherein the gas processing unit is connected with a tee joint, one interface of the tee joint is connected with an exhaust throttle valve, and the other interface of the tee joint is communicated with the air pump;
the gas treatment unit comprises a main body, a silicon rubber decompression film, a pressure regulating line board and a flow regulating shaft, wherein the silicon rubber decompression film and the pressure regulating line board are respectively fixed on two sides of the main body, and the flow regulating shaft is arranged on the gas outlet side of the main body and used for controlling the gas flow speed and the gas flow pressure.
As a preferred example, the pressure sensor is in communication with the gas treatment unit via a pressure sensor end quick connector located in the gas treatment unit's outlet end line to the needle.
As a preferred example, the flow sensor is connected to the gas treatment unit by a connection unit, which mounts a needle by a needle mount.
As a preferred example, the needle mount is provided with a temperature sensor.
As a preferred example, the temperature sensor is a non-contact infrared temperature sensor.
As a preferable example, the pressure regulating circuit board comprises a pressure regulating circuit board air inlet, a pressure regulating circuit board high-flow air outlet, a pressure regulating circuit board air buffer opening and a pressure regulating circuit board low-flow air outlet, wherein the inlet and the outlet are mutually communicated.
As a preferred example, the flow regulating shaft includes a main shaft on which a right seal ring, a middle seal ring, and a left seal ring are provided.
As a preferable example, the main body is provided with a main body air outlet, a main body air storage cavity, a main body air inlet, a main body and a large-flow air inlet of a flow regulating shaft, an air outlet of the main body towards the needle head side and a small-flow air inlet of the main body and the flow regulating shaft;
the main body air outlet is communicated with the air inlet of the voltage regulating line board;
the main body is communicated with a large-flow air inlet of the flow regulating shaft and a large-flow air outlet of the pressure regulating line board;
the main body is communicated with the small-flow air inlet of the flow regulating shaft and the small-flow air outlet of the pressure regulating line board;
the main body gas storage cavity and the pressure regulating line board are respectively arranged on two sides of the main body, and the main body gas storage cavity is arranged close to the silicon rubber pressure reducing film.
As a preferred example, the main body is further provided with a main body air outlet pipeline towards the needle head side, a main body air outlet pipeline connector towards the needle head side, a main body air outlet pipeline towards the pressure sensor side, a main body pressure sensor side connector and a through hole for installing a flow regulating shaft, wherein the cross section area calculated by the line width and the line depth of the pressure regulating circuit board is smaller than the cross section area of the main body air outlet pipeline towards the needle head side.
A method for testing dynamic surface tension by a bubble pressure method comprises the following steps:
s1, initializing the flow speed range of a gas input system and the exhaust volume of an exhaust throttle valve:
in the air, the running speed of the air pump is controlled by adopting a PWM mode through the control unit, the pressure value on the control unit is read, and the exhaust quantity of the exhaust throttle valve is opened from small to large according to the change condition of the pressure value until the pressure value does not change;
s2, dynamic surface tension test:
after the needle is immersed into the tested sample for setting depth, the running speed of the air pump is controlled by adopting a PWM mode through the control unit, the running speed is from high to low, the pressure value and the change curve of the pressure sensor are read, and the flow value and the change curve of the flow sensor are read;
according to the read maximum pressure value, calculating to obtain a surface tension value by adopting a bubble pressure method Younglaplace equation:
γ=f*r 0 * P/2, wherein gamma is the surface tension value, f is the correction factor, r 0 The radius of the inner diameter of the needle, P is a pressure value, and the F correction factor adopts a BendURE correction formula;
s3, testing dynamic surface tension value, dynamic surface tension dead time, bubble life and bubble time:
testing the change time of the rising section from the lowest value to the maximum value as the bubble life and the change time of the falling section from the maximum value to the minimum value as the dead time through the pressure value change curve read in S2, wherein the bubble time = the bubble life + the dead time;
the change time of the descending section from the highest value to the lowest value is the bubble life, the change time of the descending section from the lowest value to the maximum value is the dead time, and meanwhile, the bubble time = the bubble life + the dead time;
testing a plurality of rising and falling periods, and averaging the time as above and then calculating the average as a final result;
s, measuring the equilibrium surface tension:
the operation speed of the air pump is controlled from high to low in a PWM mode through the control unit, when the pressure value does not change in height, namely, the operation speed is further reduced until the pressure value becomes smaller and exceeds a set threshold value, the air pump is controlled to increase in speed until the pressure value is larger than the pressure change threshold value again, the maximum pressure value which is smaller than the pressure change threshold value and is generated in the process is regarded as the pressure value for calculating the balance surface tension, and the balance surface tension is calculated by adopting a formula in S2.
The beneficial effects of the invention are as follows: according to the invention, the three-way valve, the exhaust throttle valve, the air storage cavity pressing plate and the silicon rubber decompression film are added on the air treatment unit, and meanwhile, the problems that the surface tension of the existing bubble pressure method is easily influenced by bubble operation pulses, is influenced by the extra pressure of the air pump, the calculation of the dynamic surface tension time is inaccurate, the balance surface tension of the surfactant in the bubble pressure method cannot be obtained through testing and the like are effectively solved in a mode that the air inlet pipeline cross section of the air treatment unit is smaller than the air outlet pipeline cross section of the needle. The surface tension test device can greatly improve the surface tension value test precision of the dynamic surface tension of the surfactant and the test precision of the adsorption time, can be widely applied to industries such as chemical industry, materials, electrons, semiconductors, cosmetics, pesticides, coatings and the like, and has great application and popularization values.
Drawings
FIG. 1 is a schematic diagram of the structure of the present invention;
FIG. 2 is a schematic side view of the structure of the present invention;
FIG. 3 is a schematic side view of the structure of the present invention;
FIG. 4 is a schematic view of the mounting structure of the flow adjustment shaft of the gas treatment unit of the present invention;
FIG. 5 is a schematic view of a flow control shaft according to the present invention;
FIG. 6 is a schematic diagram of the front structure of a voltage regulating line board according to the present invention;
FIG. 7 is a schematic view showing the front structure of a main body of a gas processing unit according to the present invention;
fig. 8 is a schematic side view of a gas processing unit body according to the present invention.
In the figure: the pressure sensor 1, the connecting air pipe 2, the pressure sensor end quick connector 3, the gas processing unit 4, the gas inlet end quick connector 5, the connecting air pipe 6, the tee joint 7, the connecting air pipe 8, the exhaust throttle valve 9, the connecting air pipe 10, the air pump 11, the control unit 12, the connecting unit 13, the flow sensor connecting pipe 14, the flow sensor 15, the flow sensor connecting pipe 16, the needle seat 17, the needle 18, the temperature sensor 19, the gas storage cavity pressure plate 4-1, the silicone rubber pressure reducing film 4-2, the main body 4-3, the pressure regulating circuit board 4-4, the silicone rubber cushion block 4-5, the pressure reducing cavity pressure plate 4-6, the flow regulating shaft 4-7, the sealing ring 13-1, the connecting block 13-2, the jackscrew 13-3, the an end face sealing ring 13-4, a right side handle 4-7-1, a main shaft 4-7-2, a right sealing ring 4-7-3, a middle sealing ring 4-7-4, a left sealing ring 4-7-5, a left side handle 4-7-6, a pressure regulating circuit board air inlet 4-4-1, a pressure regulating circuit board high-flow air outlet 4-4-2, a pressure regulating circuit board air buffer port 4-4-3, a pressure regulating circuit board low-flow air outlet 4-4-4, a main body air outlet 4-3-1, a main body air storage cavity 4-3-2, a main body air inlet 4-3-3, a main body and flow regulating shaft high-flow air inlet 4-3-4, a main body air outlet 4-3-5 towards a needle head side, a main body and a flow regulating shaft low-flow air inlet 4-3-6, the main body is to the air outlet pipeline 4-3-7 of syringe needle side, the main body is to the air outlet pipeline connector 4-3-8 of syringe needle side, the main body is to the pressure sensor side air pipeline 4-3-9, the pressure sensor side connector 4-3-10 of main body, the through-hole 4-3-11 of main body installation flow control axle.
Description of the embodiments
The invention will be further described with reference to the following detailed drawings, in order to make the technical means, the creation characteristics, the achievement of the purpose and the effect of the invention easy to understand.
As shown in fig. 1 and 2, a bubble pressure method surface tension testing device includes: the pressure sensor 1, the connecting air pipe 2, the pressure sensor end quick connector 3, the gas processing unit 4, the gas inlet end quick connector 5, the connecting air pipe 6, the tee joint 7, the connecting air pipe 8, the exhaust throttle valve 9, the connecting air pipe 10, the air pump 11, the control unit 12, the connecting unit 13, the flow sensor connecting pipe 14, the flow sensor 15, the flow sensor connecting pipe 16, the needle seat 17, the needle 18 and the temperature sensor 19.
The gas treatment unit 4 is fixedly connected with the gas inlet end quick connector 5 and then is connected with the tee joint 7 through the connecting gas pipe 6; one interface of the tee joint 7 is connected with an exhaust throttle valve 9 through a connecting air pipe 8, and the other interface is connected with an air pump through a connecting air pipe 10; through the design of the pipeline, the air pump 11 inputs air into the air treatment unit 4, and the extra air is discharged through the exhaust throttle valve 9, so that the influence of the pressure of the air pump 11 on the dynamic surface tension value and the influence of the running pulse of the diaphragm pump or the peristaltic pump on the dynamic surface tension value and the time are solved.
Further, the gas processing unit 4 is provided with a pressure sensor end quick connector 3, and the quick connector is positioned in a pipeline of the gas processing unit 4 towards the gas outlet end of the needle 14, so that the influence of excessive pressure on dynamic surface tension measurement and time calculation is solved; the pressure sensor end quick connector 3 is connected with the pressure sensor 1 through a connecting air pipe 2. The gas processing unit 4 is connected with a flow sensor 15 through a connecting unit 13 and a flow sensor connecting pipe 14, and specifically, the connecting unit 13 comprises a sealing ring 13-1, a connecting block 13-2, a jackscrew 13-3 and an end face sealing ring 13-4. After the end face sealing ring 13-4 is mounted on the connecting block 13-2, the connecting block 13-2 is connected with an air outlet pipeline connecting port 4-3-8 of the body processing unit main body to the needle head side through a threaded structure; after the sealing ring 13-1 is sleeved on the connecting block 13-2, the sealing ring is inserted into an inner hole of the connecting unit 13 and is fixedly connected through the jackscrew 13-3 positioned on the connecting unit 13, and the flow sensor connecting pipe 14 is communicated with a pipeline on the connecting unit 13; the flow sensor 15 is connected with the needle seat 17 through the flow sensor connecting pipe 16; the needle 18 is fixedly connected with the needle seat 17 through a thread structure, and preferably, the needle 18 adopts a wucang needle structure. .
The needle seat is fixedly provided with a temperature sensor 19, the temperature sensor 19 can be a non-contact infrared temperature sensor or a PT100 temperature sensor, and as a preferable scheme, the temperature sensor 19 is a non-contact infrared temperature sensor so as to solve the problem that the contact sensor probe is easy to influence the surface tension of a test sample.
The pressure sensor 1, the air pump 11, the flow sensor 15, and the temperature sensor 19 are all connected to the control unit 12, and the control unit 12 controls the flow of the air pump 11, reads the pressure value and the pressure value change curve, reads the flow value and the flow value change curve, and reads the temperature value and the temperature value change curve.
In one embodiment, as shown in FIG. 3, the gas treatment unit 4 includes a gas storage cavity pressure plate 4-1, a silicone rubber pressure reducing film 4-2, a gas treatment unit body 4-3, a pressure regulating circuit board 4-4, a silicone rubber cushion block 4-5, a pressure reducing cavity pressure plate 4-6, and a flow regulating shaft 4-7. The air storage cavity pressure plate 4-1 fixedly mounts the silicon rubber pressure reducing film 4-2 on one side of the gas treatment unit main body 4-3 through screws; the pressure reducing cavity pressing plate 4-6 is fixedly arranged on the other side of the gas treatment unit main body 4-3 through screws after the silicon rubber cushion block 4-5 is firstly placed and then the pressure regulating circuit board 4-4 is stacked. The gas outlet side of the gas treatment unit body 4-3 is provided with a through hole 4-3-11 for mounting a flow rate adjustment shaft, and is provided with a flow rate adjustment shaft 4-7.
Referring to fig. 4 and 5, the flow rate adjusting shaft 4-7 includes a flow rate adjusting shaft right side handle 4-7-1, a flow rate adjusting shaft main shaft 4-7-2, a right seal ring 4-7-3, a middle seal ring 4-7-4, a left seal ring 4-7-5, and a flow rate adjusting shaft left side handle 4-7-6. The flow regulating shaft main shaft 4-7-2 is provided with a flow regulating shaft left side handle 4-7-6 and a flow regulating shaft right side handle 4-7-1 respectively on the left side and the right side through a thread structure; meanwhile, a right sealing ring 4-7-3, a middle sealing ring 4-7-4 and a left sealing ring 4-7-5 are arranged on the main shaft 4-7-2 of the flow regulating shaft.
As shown in FIG. 6, the pressure regulating circuit board 4-4 comprises a pressure regulating circuit board air inlet 4-4-1, a pressure regulating circuit board high-flow air outlet 4-4-2, a pressure regulating circuit board air buffer opening 4-4-3 and a pressure regulating circuit board low-flow air outlet 4-4-4. The pressure regulating circuit board 4-4 adopts a printed circuit board processing technology or a laser engraving technology, preferably a printed circuit board processing technology, and the cross section area calculated by the line width and the line depth of the pressure regulating circuit board 4-4 is smaller than the cross section area of the gas treatment unit main body at the needle head position to the gas outlet pipeline 4-3-7 at the needle head side.
Referring to fig. 6, 7 and 8, the gas treatment unit body 4-3 includes a gas treatment unit body gas outlet 4-3-1, a gas treatment unit body gas storage chamber 4-3-1, a gas treatment unit body gas inlet 4-3-3, a gas treatment unit body and a large flow gas inlet 4-3-4 of a flow rate adjustment shaft, a gas treatment unit body gas outlet 4-3-5 to a needle side, a gas treatment unit body and a small flow gas inlet 4-3-6 of a flow rate adjustment shaft, a gas treatment unit body gas outlet pipe 4-3-7 to a needle side, a gas treatment unit body gas outlet pipe connection port 4-3-8 to a needle side, a gas treatment unit body gas pipe 4-3-9 to a pressure sensor side, a gas treatment unit body pressure sensor side connection port 4-3-10, and a gas treatment unit body mounting flow rate adjustment shaft through hole 4-3-11. The gas outlet 4-3-1 of the gas treatment unit main body is communicated with the gas inlet 4-4-1 of a pressure regulating circuit board 4-4 of the pressure regulating circuit board 4-4 arranged on the other side of the gas treatment unit main body 4-3; the high-flow air inlet 4-3-4 of the flow regulating shaft on the air treatment unit main body 4-3 is communicated with the high-flow air outlet 4-4-2 of the pressure regulating line board; the main body of the gas treatment unit is communicated with a small-flow gas inlet 4-3-6 of the flow regulating shaft and a small-flow gas outlet 4-4-4 of the pressure regulating line board; the gas storage cavity 4-3-1 of the gas treatment unit body and the pressure regulating circuit board 4-4 are respectively arranged at two sides of the gas treatment unit body 4-3.
Through the connection relation, the design and the realization mode of the whole gas pipeline are as follows:
(1) Inputting gas and controlling gas flow speed: the control unit 12 controls the flow rate of the air pump 11 to input air into the air storage cavity 4-3-1 of the main body of the air treatment unit;
(2) Treatment of pressure increase due to excessive gas flow rate: through innovatively adding the tee joint 7 and the exhaust throttle valve 8 at the input air end, and adding the gas storage cavity pressure plate 4-1 and the silicone rubber pressure reducing film 4-2 on the gas processing unit 4, the gas is input at the highest speed and the lowest speed, the switch of the exhaust throttle valve 8 is adjusted from small to large according to whether the pressure of the pressure sensor is changed at different speeds, the silicone rubber pressure reducing film 4-2 rebounds the gas with overlarge flow, and the exhaust throttle valve 8 discharges the excessive gas, so that the influence of the operation pulse of the gas pump and the additional gas on the pressure is realized, and the dynamic surface tension value and the dynamic surface tension adsorption time are accurately tested.
(3) Measurement of equilibrium surface tension is achieved: pushing the handle 4-7-6 at the left side of the flow regulating shaft to the right, wherein the large-flow air inlet 4-3-4 of the flow regulating shaft on the main body 4-3 of the gas treatment unit is communicated with the large-flow air outlet 4-4-2 of the pressure regulating line plate and positioned between the left sealing ring 4-7-5 and the middle sealing ring 4-7-4, so that the large-flow air inlet is sealed and disconnected with the air outlet pipeline connecting port 4-3-8 of the main body of the gas treatment unit towards the needle head side, and at the moment, only the small-flow air inlet 4-3-6 of the main body of the gas treatment unit and the flow regulating shaft are communicated with the air outlet pipeline connecting port 4-3-8 of the pressure regulating line plate, which is communicated with the small-flow air outlet 4-4-4 of the pressure regulating line plate, and the gas flow is smaller. Pushing the handle 4-7-1 on the right side of the flow regulating shaft to the left, and arranging two air outlet holes between the right sealing ring 4-7-3 and the middle sealing ring 4-7-4, thereby improving the flow and being used for surface tension test with shorter dynamic surface tension adsorption time. The large flow and position change of the sealing ring on the flow adjusting shaft and the gas processing unit main body are combined with the opening and closing size of the exhaust throttle valve, so that the flow adjustment in a larger range is realized, and the measurement of the balance surface tension is supported on hardware.
The connecting unit 13 comprises a sealing ring 13-1, a connecting block 13-2, a jackscrew 13-3 and an end face sealing ring 13-4. After the end face sealing ring 13-4 is mounted on the connecting block 13-2, the connecting block 13-2 is connected with an air outlet pipeline connecting port 4-3-8 of the body processing unit main body to the needle head side through a threaded structure; after the sealing ring 13-1 is sleeved on the connecting block 13-2, the sealing ring is inserted into an inner hole of the connecting unit 13 and is fixedly connected through the jackscrew 13-3 positioned on the connecting unit 13.
According to the above testing device, a method for testing dynamic surface tension by using a bubble pressure method is provided, which comprises the following steps:
s1, initializing the flow speed range of a gas input system and the exhaust volume of an exhaust throttle valve:
in the air, the running speed of the air pump 11 is controlled by a control unit 12 in a PWM mode, the pressure value on the control unit 12 is read, and the exhaust amount of the exhaust throttle valve 9 is opened from small to large according to the change condition of the pressure value until the pressure value does not change;
s2, dynamic surface tension test:
after the needle 14 is immersed into the tested sample for setting depth, the running speed of the air pump 11 is controlled by adopting a PWM mode through the control unit 12, the running speed is from high to low, the pressure value and the change curve of the pressure sensor 1 are read, and the flow value and the change curve of the flow sensor 16 are read;
according to the read maximum pressure value, calculating to obtain a surface tension value by adopting a Young-displacement equation of a bubble pressure method;
γ=f*r 0 * P/2, wherein gamma is the surface tension value, f is the correction factor, r 0 Is the radius of the inner diameter of the needle, and P is the pressure value. The F correction factor uses a bond correction formula.
S3, testing dynamic surface tension value, dynamic surface tension dead time (dead time), bubble life (bubble time) and bubble time (bubble life):
the change time of the rising section from the lowest value to the maximum value is tested as bubble life (bubble time) and the change time of the falling section from the maximum value to the minimum value is tested as dead time (dead time) through the pressure value change curve read in S2, and meanwhile, the bubble time (bubble life) =the bubble life (bubble time) +the dead time (dead time);
the change time of the descending section from the highest value to the lowest value is bubble life (bubble time), the change time of the descending section from the lowest value to the maximum value is dead time (dead time), and the bubble time (bubble life) =bubble life (bubble time) +dead time (dead time);
multiple ramp-up and ramp-down periods are tested and averaged over time as above to yield the final result.
S4, measuring the equilibrium surface tension:
the control unit 12 controls the running speed of the air pump 11 from fast to slow in a PWM mode, when the pressure value does not change in height, namely, the running speed is further reduced until the pressure value becomes smaller and exceeds a set threshold value, then the air pump 11 is controlled to increase in speed until the pressure value appears again and is larger than the pressure change threshold value, the maximum pressure value which appears in the process and is smaller than the pressure change threshold value is regarded as the pressure value for calculating the balance surface tension, and the balance surface tension is calculated by adopting a formula in S2.
The foregoing has shown and described the basic principles and main features of the present invention and the advantages of the present invention. It will be appreciated by persons skilled in the art that the present invention is not limited to the embodiments described above, but is capable of numerous variations and modifications without departing from the spirit and scope of the invention as hereinafter claimed. The scope of the invention is defined by the appended claims and equivalents thereof.
Claims (10)
1. The utility model provides a bubble pressure method dynamic surface tension's testing arrangement, includes pressure sensor (1), air pump (11), control unit (12), flow sensor (15) and syringe needle (18), its characterized in that: the air treatment device comprises an air pump (11), and further comprises an air treatment unit (4), wherein the air treatment unit (4) is connected with a tee joint (7), one interface of the tee joint (7) is connected with an exhaust throttle valve (9), and the other interface is communicated with the air pump (11);
the gas treatment unit (4) comprises a main body (4-3), a silicone rubber decompression film (4-2), a pressure regulating circuit board (4-4) and a flow regulating shaft (4-7), wherein the silicone rubber decompression film (4-2) and the pressure regulating circuit board (4-4) are respectively fixed on two sides of the main body (4-3), and the flow regulating shaft (4-7) is arranged on the gas outlet side of the main body (4-3) and used for controlling the gas flow speed and the gas flow pressure.
2. The bubble pressure method dynamic surface tension testing device according to claim 1, wherein: the pressure sensor (1) is communicated with the gas treatment unit (4) through a pressure sensor end quick connector (3), and the pressure sensor end quick connector (3) is positioned in a gas outlet end pipeline from the gas treatment unit (4) to the needle head (18).
3. The bubble pressure method dynamic surface tension testing device according to claim 1, wherein: the flow sensor (15) is connected with the gas treatment unit (4) through a connecting unit (13), and the connecting unit (13) is provided with a needle (18) through a needle seat (17).
4. A device for testing dynamic surface tension according to claim 3, wherein: the needle seat (17) is provided with a temperature sensor (19).
5. The bubble pressure method dynamic surface tension testing device according to claim 4, wherein: the temperature sensor (19) is a non-contact infrared temperature sensor.
6. The bubble pressure method dynamic surface tension testing device according to claim 1, wherein: the pressure regulating circuit board (4-4) comprises a pressure regulating circuit board air inlet (4-4-1), a pressure regulating circuit board high-flow air outlet (4-4-2), a pressure regulating circuit board air buffer opening (4-4-3) and a pressure regulating circuit board low-flow air outlet (4-4-4), wherein the inlet and the outlet are mutually communicated.
7. The bubble pressure method dynamic surface tension testing device according to claim 6, wherein: the flow regulating shaft (4-7) comprises a main shaft (4-7-2), and a right sealing ring (4-7-3), a middle sealing ring (4-7-4) and a left sealing ring (4-7-5) are arranged on the main shaft (4-7-2).
8. The bubble pressure method dynamic surface tension testing device according to claim 7, wherein: the main body (4-3) is provided with a main body air outlet (4-3-1), a main body air storage cavity (4-3-2), a main body air inlet (4-3-3), a main body and large-flow air inlet (4-3-4) of a flow regulating shaft, an air outlet (4-3-5) of the main body towards the needle head side and a small-flow air inlet (4-3-6) of the main body and the flow regulating shaft;
the main body air outlet (4-3-1) is communicated with the pressure regulating circuit board air inlet (4-4-1);
the main body is communicated with a large-flow air inlet (4-3-4) of the flow regulating shaft and a large-flow air outlet (4-4-2) of the pressure regulating line board;
the main body is communicated with a small-flow air inlet (4-3-6) of the flow regulating shaft and a small-flow air outlet (4-4-4) of the pressure regulating line board;
the main body air storage cavity (4-3-2) and the pressure regulating line board (4-4) are respectively arranged on two sides of the main body (4-3), and the main body air storage cavity (4-3-2) is close to the silicon rubber pressure reducing film (4-2).
9. The bubble pressure method dynamic surface tension testing device according to claim 8, wherein: the pressure regulating circuit is characterized in that an air outlet pipeline (4-3-7) from the main body to the needle side, an air outlet pipeline connecting port (4-3-8) from the main body to the needle side, an air pipeline (4-3-9) from the main body to the pressure sensor side, a pressure sensor side connecting port (4-3-10) from the main body and a through hole (4-3-11) for installing a flow regulating shaft on the main body are further arranged on the main body (4-3), wherein the cross section area calculated by the line width and the line depth of the pressure regulating circuit board (4-4) is smaller than the cross section area of the air outlet pipeline (4-3-7) from the main body to the needle side.
10. The method for testing dynamic surface tension by using bubble pressure method according to claim 1, wherein the method comprises the following steps: the method comprises the following steps:
s1, initializing the flow speed range of a gas input system and the exhaust volume of an exhaust throttle valve:
in the air, the running speed of the air pump (11) is controlled by a control unit (12) in a PWM mode, the pressure value on the control unit (12) is read, and the exhaust quantity of the exhaust throttle valve (9) is opened from small to large according to the change condition of the pressure value until no change occurs in the pressure value;
s2, dynamic surface tension test:
after immersing the needle (18) into a tested sample for setting depth, controlling the running speed of the air pump (11) by adopting a PWM mode through the control unit (12), reading the pressure value and the change curve of the pressure sensor (1) and the flow value and the change curve of the flow sensor (15) from high to low;
according to the read maximum pressure value, calculating to obtain a surface tension value by adopting a Young-displacement equation of a bubble pressure method:
γ=f*r 0 * P/2, wherein gamma is the surface tension value, f is the correction factor, r 0 The radius of the inner diameter of the needle, P is a pressure value, and the F correction factor adopts a BendURE correction formula;
s3, testing dynamic surface tension value, dynamic surface tension dead time, bubble life and bubble time:
testing the change time of the rising section from the lowest value to the maximum value as the bubble life and the change time of the falling section from the maximum value to the minimum value as the dead time through the pressure value change curve read in S2, wherein the bubble time = the bubble life + the dead time;
the change time of the descending section from the highest value to the lowest value is the bubble life, the change time of the descending section from the lowest value to the maximum value is the dead time, and meanwhile, the bubble time = the bubble life + the dead time;
testing a plurality of rising and falling periods, and averaging the time as above and then calculating the average as a final result;
s4, measuring the equilibrium surface tension:
the control unit (12) controls the running speed of the air pump (11) from high to low in a PWM mode, when the pressure value does not change in height, namely, is smaller than a set pressure change threshold value, the speed is further reduced until the pressure value becomes smaller and exceeds the set threshold value, the air pump (11) is controlled to increase in speed until the pressure value appears again and is larger than the pressure change threshold value, the maximum pressure value which appears in the process and is smaller than the pressure change threshold value is regarded as the pressure value for calculating the balance surface tension, and the balance surface tension is calculated by adopting a formula in S2.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202311052513.2A CN117054295A (en) | 2023-08-21 | 2023-08-21 | Device and method for testing dynamic surface tension by bubble pressure method |
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| CN202311052513.2A CN117054295A (en) | 2023-08-21 | 2023-08-21 | Device and method for testing dynamic surface tension by bubble pressure method |
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| CN117054295A true CN117054295A (en) | 2023-11-14 |
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| CN202311052513.2A Pending CN117054295A (en) | 2023-08-21 | 2023-08-21 | Device and method for testing dynamic surface tension by bubble pressure method |
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