Liquid viscosity measuring system and auxiliary device

Abstract

The invention discloses a liquid viscosity measuring system and an auxiliary device. The device comprises a measuring tube, a liquid level sensor and an auxiliary device, the sensor assembly is arranged at one end of the measuring tube and comprises a PCB (Printed Circuit Board) and an ultrasonic transducer on the PCB, and the PCB is configured to excite the ultrasonic transducer to transmit an ultrasonic signal and collect the ultrasonic signal received by the ultrasonic transducer; the reflecting end is arranged at the other end of the measuring tube and faces the ultrasonic transducer, a closed measuring space is formed between the reflecting end and the sensor assembly, so that liquid cannot leak after being injected into the measuring space, and an ultrasonic signal transmitted by the ultrasonic transducer can be reflected back by the reflecting end after penetrating through the liquid and is received by the ultrasonic transducer; and the propagation speed and signal attenuation of the ultrasonic waves related to the liquid viscosity in the liquid are obtained based on the ultrasonic signals received by the ultrasonic transducer. According to the invention, the propagation velocity and signal attenuation of ultrasonic waves in different liquid media are accurately measured by flexibly changing measurement conditions, so that accurate evaluation of the liquid viscosity is realized.

Description

Technical Field

[0001] The present invention relates to measuring the viscosity of liquid by utilizing ultrasonic wave. Background Art

[0002] In many fields such as chemistry, biology, medicine and industrial production, the viscosity of liquid is a crucial physical parameter, which directly affects the flow properties, transmission efficiency and process control of liquids. Although traditional liquid viscosity measuring instruments, such as rotational viscometers and pipettes, can meet the measurement needs to a certain extent, they often have disadvantages such as limited measurement accuracy, complex operation and contamination of samples. Especially when it is necessary to monitor or process high-viscosity, volatile or toxic liquids online, the limitations of traditional instruments are particularly obvious.

[0003] In recent years, with the rapid development of ultrasonic technology, its application in liquid viscosity measurement has gradually attracted attention. Ultrasonic measurement technology has the advantages of non-contact, high precision, fast response and no need for sample processing, which can effectively overcome the shortcomings of traditional measurement methods. When ultrasonic waves propagate in liquids, their speed and attenuation are closely related to the viscosity of the liquid. By accurately measuring the propagation speed and signal attenuation of ultrasonic waves under different conditions, the viscosity parameters of the liquid can be indirectly calculated. However, most of the existing ultrasonic viscosity measurement devices have problems such as single measurement conditions and poor adaptability, and cannot fully reflect the changing laws of liquid viscosity under different external conditions (such as temperature, concentration, etc.). In addition, in-depth research on the propagation characteristics of ultrasonic waves in liquids is relatively insufficient, resulting in the need to improve the accuracy and reliability of the measurement results.

[0004] Therefore, developing an ultrasonic viscosity measuring device that can flexibly change the measurement environment and accurately measure the speed and attenuation of ultrasonic waves in different media is of great significance for improving the accuracy and efficiency of liquid viscosity measurement. The device for measuring liquid viscosity based on ultrasonic waves of the present invention is an innovative solution to the above problems. Summary of the invention

[0005] The present invention provides a liquid viscosity measurement system and an auxiliary device, which can accurately measure the propagation speed and signal attenuation of ultrasonic waves in different liquid media by flexibly changing the measurement conditions, thereby achieving accurate evaluation of the liquid viscosity.

[0006] In a first aspect, a liquid viscosity measurement auxiliary device is proposed, which is used to measure the propagation speed and signal attenuation of ultrasonic waves in liquid when measuring the viscosity of the liquid. The device comprises: a measuring tube; a sensor assembly, which is arranged at one end of the measuring tube, and comprises a PCB and an ultrasonic transducer thereon, and the PCB is configured to excite the ultrasonic transducer to emit ultrasonic signals and collect ultrasonic signals received by the ultrasonic transducer; and a reflection end, which is arranged at the other end of the measuring tube, facing the ultrasonic transducer, and forming a closed measuring space with the sensor assembly, so that the liquid will not leak after being injected into the measuring space, and the ultrasonic signal emitted by the ultrasonic transducer can be reflected back by the reflection end after penetrating the liquid, and received by the ultrasonic transducer; based on the ultrasonic signal received by the ultrasonic transducer, the propagation speed and signal attenuation of ultrasonic waves in the liquid related to the viscosity of the liquid are obtained.

[0007] In some examples, the sensor assembly is disposed in a packaging shell, a radial dimension of the packaging shell is consistent with an inner diameter of the measuring tube, and at least a portion of the packaging shell facing the reflection end is treated with an anti-penetration material that matches the acoustic impedance of the liquid.

[0008] In some examples, the material is PDMS or polyurethane.

[0009] In some examples, the packaging shell has at least one rubber ring on a circumferential surface thereof to enhance sealing performance with the measuring tube.

[0010] In some examples, the reflection end is fixed to one end of a sliding component, and the other end of the sliding component is connected to a push-pull rod for pushing it to move in the measuring tube to approach or move away from the ultrasonic transducer, and the push-pull rod has a handle.

[0011] In some examples, a plug is installed at one end of the measuring tube to provide support for the push-pull rod, guide its movement, and prevent leakage of liquid. The push-pull rod passes through the plug and is connected to the handle.

[0012] In some examples, the sliding component has at least one rubber on its circumferential surface to enhance sealing performance with the measuring tube.

[0013] In some examples, the measuring tube is made of a transparent material and has a scale thereon reflecting the distance between the ultrasonic transducer and the reflecting end.

[0014] In some examples, the PCB has a first interface for acquiring an excitation signal for stimulating the ultrasonic transducer from a signal generator, and a second interface for sending the collected ultrasonic signal to an oscilloscope and / or a computer; or

[0015] The PCB is configured to generate an excitation signal for exciting the ultrasonic transducer, and convert the measured ultrasonic propagation velocity and signal attenuation into the viscosity of the liquid based on a mathematical model between the ultrasonic propagation velocity, signal attenuation and liquid viscosity.

[0016] In a second aspect, a liquid viscosity measurement system is provided, characterized in that it comprises: the liquid viscosity measurement auxiliary device described above; a signal generator that provides an excitation signal to the ultrasonic transducer of the device; and an oscilloscope that displays the ultrasonic signal received by the ultrasonic transducer; and the liquid viscosity is calculated based on a mathematical model between ultrasonic wave propagation velocity, signal attenuation and liquid viscosity, as well as the ultrasonic wave propagation velocity and signal attenuation obtained by the device in the liquid.

[0017] First, the invention adopts a non-contact measurement method to avoid the contamination and damage to the sample in the traditional method; second, by flexibly changing the measurement environment (liquid concentration, temperature, distance), it can comprehensively reflect the change law of liquid viscosity under different external conditions; thirdly, the device / system has a simple structure and convenient operation, and is suitable for rapid measurement of various liquid viscosities; finally, the present invention can provide high-precision and high-reliability measurement results. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of a liquid viscosity measurement auxiliary device according to an embodiment of the present invention.

[0019] Figure 2 is a schematic diagram of a measuring tube according to an embodiment of the present invention.

[0020] Figure 3 is a schematic diagram of an ultrasonic transducer according to an embodiment of the present invention.

[0021] Figure 4 is a schematic diagram of a sensor assembly according to an embodiment of the present invention.

[0022] Figure 5 is a cross-sectional view of a sensor assembly according to an embodiment of the present invention.

[0023] Figure 6 Schematic diagram of a liquid viscosity measurement system according to an embodiment of the present invention.

[0024] Figure 7 2 is a schematic diagram of a transmitting end and a position adjustment structure thereof according to an embodiment of the present invention.

[0025] Figure 8 Schematic diagram of a measuring tube support base according to an embodiment of the present invention. DETAILED DESCRIPTION

[0026] The liquid viscosity measurement auxiliary device and system of the present invention can measure liquids including but not limited to biological liquids such as polymer solutions, blood, and lymph, as well as industrial liquids such as chemical raw materials and petroleum products.

[0027] The mathematical model for liquid viscosity testing is:

[0028]

[0029] η is the viscosity coefficient, ρ is the liquid density, U is the speed of ultrasonic wave propagation in the liquid, α is the attenuation coefficient (also called absorption coefficient), and f is the natural frequency of the ultrasonic transducer.

[0030]

[0031] The attenuation coefficient α is also called the absorption coefficient, which is a property of the medium affected by environmental factors. The nth amplitude in the frequency domain of the ultrasonic signal is defined as An, where n = 0 represents the amplitude of the initial pulse, n = 1 represents the first echo, n = 2 represents the second echo, and so on. Due to the dissipation of acoustic energy, the echo amplitude decays with time and flight distance.

[0032] By measuring the propagation time of ultrasound in liquid and the amplitude attenuation of echo, combined with the known formula of the propagation speed of sound waves in liquid (such as distance = (sound speed × echo time) / 2), the actual propagation speed of ultrasound in different media conditions can be calculated. At the same time, the amplitude attenuation of echo also reflects the degree of absorption of ultrasonic energy by liquid, which is closely related to the viscosity of the liquid.

[0033] Based on the mathematical model between ultrasonic propagation velocity, signal attenuation and liquid viscosity, the measured ultrasonic propagation velocity and signal attenuation can be converted into liquid viscosity parameters. In addition, the influence of external environment such as temperature and concentration on the measurement results is taken into account to improve the accuracy and reliability of the measurement results.

[0034] Figure 1 A liquid viscosity measurement auxiliary device is shown. The device can at least measure the propagation speed and signal attenuation of ultrasonic waves in liquids. Figure 1 As shown, the device comprises a measuring tube 10, a sensor assembly 20 and a reflecting end 30. The measuring tube 10 is used to contain the liquid to be measured. Figure 2 Schematic diagram of measuring tube 10. The measuring tube 10 has a nozzle 11 on its circumferential surface, through which liquid is injected and discharged, and a syringe 40 can be used to inject or discharge liquid. The sensor assembly 20 and the reflection end 30 are located at both ends of the measuring tube 10, and a closed measuring space is formed between them, and the measured liquid is located in the closed space. The sensor assembly 20 includes a printed circuit board (PCB) 21 and an ultrasonic transducer 25 thereon.

[0035] In one embodiment, the measuring tube 10 can be made of a transparent material, such as acrylic. The light transmittance of acrylic is 92%, which can better show the changes in the liquid and the distance between the sensor assembly 20 and the reflective end 30. Acrylic also has the characteristics of good chemical stability, high hardness, excellent electrical insulation performance, light weight, high strength, good impact resistance, and not easy to break.

[0036] Figure 3 Schematic diagram of ultrasonic transducer 25. Ultrasonic transducer 25 is a transceiver integrated device for transmitting and receiving ultrasonic signals. It can be a capacitive micro-machined ultrasonic transducer or a piezoelectric micro-machined ultrasonic transducer.

[0037] like Figure 4 , Figure 5 As shown, the ultrasonic transducer 25 is arranged on a printed circuit board (PCB) 21, specifically, the PAD point on the ultrasonic transducer chip is bonded to the PCB lead. The PCB 21 is not only a carrier of the ultrasonic transducer, but also used to excite the ultrasonic transducer to transmit an ultrasonic signal and collect the echo signal received by the ultrasonic transducer. The excitation signal can be provided by a signal generator, and the echo signal collected by the PCB can be transmitted to an oscilloscope or a computer for display, storage, and viscosity analysis and calculation. Two wires for transmitting the excitation signal and the ultrasonic echo signal are led out from the PCB, and a BNC interface is left on the wire.

[0038] Continue to refer Figure 4 , Figure 5 , PCB 21 is arranged in the packaging shell 22. The radial dimension of the packaging shell 22 is consistent with the inner diameter of the measuring tube 10, ensuring that there is no gap between it and the tube wall after it is assembled into the measuring tube 10. The ultrasonic transducer 20 on the PCB 21 faces the reflection end 30. It is best for the ultrasonic transducer 20 to remain parallel to the reflection end 30. The packaging shell 22 (at least the part facing the reflection end 30) is made of a material 23 with low acoustic impedance and matching the acoustic impedance of the measured liquid to perform anti-penetration treatment to prevent liquid from entering and affecting the PCB 21 and the ultrasonic transducer 20. This sealing material 23 can be PDMS or polyurethane sealing. In order to enhance the sealing between the packaging shell 22 and the measuring tube 10 and prevent liquid leakage, the circumferential surface of the packaging shell 22 is provided with at least one rubber ring 24.

[0039] The wires for transmitting the excitation signal and the ultrasonic echo signal pass through the packaging shell 22, extend outside the measuring tube 10, and are connected to external instruments. The wires can be packaged in the wire slot 24. Figure 6As shown, the measuring instrument includes a signal generator, a preamplifier, a power amplifier, and an oscilloscope. These measuring instruments and the liquid viscosity measurement auxiliary device constitute a liquid viscosity measurement system. The preamplifier amplifies the ultrasonic signal received by the ultrasonic transducer and converts it into an electrical signal. The power amplifier amplifies the excitation signal generated by the signal generator.

[0040] In another embodiment, PCB 21 generates an excitation signal and processes the collected ultrasonic echo signal to calculate the liquid viscosity. In this case, the device also includes a display screen and an information input component. The liquid viscosity and other parameters required in the calculation process, such as density, can be displayed on the display screen. The information input component is used to input the parameters required for calculating the viscosity, such as the liquid density.

[0041] The reflective end 30 is made of a hard and smooth structure, and can perfectly reflect the ultrasonic signal emitted by the ultrasonic transducer. In one embodiment, the reflective end 30 can be made of a metal sheet, such as an iron sheet, an aluminum sheet, or a copper sheet.

[0042] In a preferred embodiment, the distance between the sensor assembly 20 and the reflective end 30 can be adjusted, so that the flying distance of the ultrasonic wave in the liquid can be changed, and the viscosity test distance condition can be controlled. The following is an example in which the position of the sensor assembly 20 is fixed and the position of the reflective end 30 can be adjusted. The present invention does not exclude a solution in which the positions of the sensor assembly 20 and the reflective end 30 can be adjusted, or a solution in which the position of the sensor assembly 20 can be adjusted and the position of the reflective end 30 is fixed.

[0043] like Figure 7 As shown, the reflection end 30 is fixed to one end of the sliding component 31, and the other end of the sliding component 31 is connected to the push-pull rod 32, and the push-pull rod 32 has a handle 33. Holding the handle 33, the sliding component 31 is pushed or pulled through the push-pull rod 32 to slide in the measuring tube 10, so that the reflection end 30 is close to or away from the ultrasonic transducer 20. The sliding component 31 and the push-pull rod 32 can be connected by threads. In one embodiment, the sliding component 31 can be rubber. In another embodiment, the sliding component 31 can be made of other materials other than rubber, for example, it is integrated with the reflection end 30, but has at least one rubber ring 34 on its circumferential surface, and the rubber ring 34 is in close contact with the measuring tube 10, so that the sliding component 31 can slide and ensure that the liquid will not leak.

[0044] In order to provide support for the push-pull rod 32, guide its movement, and prevent leakage of liquid, a plug 35 is installed at one end of the measuring tube 10. The plug 35 is connected to the measuring tube 10 by a thread or a mortise and tenon joint. The push-pull rod 32 passes through the plug 35 and is connected to the handle 33. The push-pull rod 32 maintains sliding contact with the plug 35.

[0045] Two supports 12 are used to support the two ends of the measuring tube 10 respectively. Figure 8 Schematic diagram of the support 12. The distance between the ultrasonic transducer 20 and the reflection end 30 (ultrasonic signal propagation distance) is measured by a scale 13. The scale 13 is of course parallel to the measuring tube 10. In one embodiment, the two ends of the scale 13 are respectively fixed on two supports 12. In addition, the scale 13 may not be configured separately, but a scale may be set on the surface of the measuring tube 10. The ultrasonic signal propagation distance can be directly read through the scale 13 or the scale on the surface of the measuring tube 10.

[0046] The measuring tube 10 provides a closed and flexible measuring environment, which not only avoids the contamination and damage of the sample in the traditional method, but also can accurately change the environment such as the concentration, temperature and the test distance (the distance between the ultrasonic transducer and the reflection end) of the liquid. After measuring a liquid of a concentration / temperature, it is poured out, and then another liquid of a concentration / temperature is added to the measuring tube through a sterile syringe.

[0047] The present invention obtains the viscosity parameters of the liquid by precisely changing the measurement environment. The user is allowed to set the same temperature to change the concentration of the liquid, or set the same concentration to change the temperature of the liquid, so as to observe the propagation speed and signal attenuation of the ultrasonic wave under different conditions. In addition, by adjusting the position of the reflection end 30, the propagation distance of the ultrasonic wave in the liquid can also be changed to further enrich the measurement data. The flexible changes of these measurement environments enable the present invention to fully reflect the changing laws of liquid viscosity under different external environments. During the measurement process, the transceiver-transmitter ultrasonic transducer 20 transmits an ultrasonic signal, which penetrates the liquid and is reflected back by the reflection end 30 on the sliding component 31, and the transducer receives the echo and analyzes it.

Claims

1. A liquid viscosity measurement auxiliary device, characterized in that: The device is used to measure the propagation speed and signal attenuation of ultrasonic waves in liquid when measuring the viscosity of liquid. The device comprises: Measuring tube; A sensor assembly, which is arranged at one end of the measuring tube, comprises a PCB and an ultrasonic transducer thereon, wherein the PCB is configured to excite the ultrasonic transducer to transmit an ultrasonic signal and collect the ultrasonic signal received by the ultrasonic transducer; A reflection end, which is arranged at the other end of the measuring tube, faces the ultrasonic transducer, and forms a closed measuring space with the sensor assembly, so that the liquid will not leak after being injected into the measuring space, and the ultrasonic signal emitted by the ultrasonic transducer can be reflected back by the reflection end after penetrating the liquid and received by the ultrasonic transducer; The propagation speed of the ultrasonic wave in the liquid and the signal attenuation related to the viscosity of the liquid are obtained based on the ultrasonic signal received by the ultrasonic transducer.

2. The liquid viscosity measurement auxiliary device according to claim 1, characterized in that: The sensor assembly is arranged in a packaging shell, the radial dimension of the packaging shell is consistent with the inner diameter of the measuring tube, and at least the portion of the packaging shell facing the reflection end is treated with an anti-penetration material that matches the acoustic impedance of the liquid.

3. The liquid viscosity measurement auxiliary device according to claim 2, characterized in that: The material is PDMS or polyurethane.

4. The liquid viscosity measurement auxiliary device according to claim 2, characterized in that: The packaging shell has at least one rubber ring on its circumferential surface to enhance the sealing performance with the measuring tube.

5. The liquid viscosity measurement auxiliary device according to claim 1, characterized in that: The reflecting end is fixed to one end of the sliding component, and the other end of the sliding component is connected to a push-pull rod for pushing it to move in the measuring tube to approach or move away from the ultrasonic transducer, and the push-pull rod is provided with a handle.

6. The liquid viscosity measurement auxiliary device according to claim 5, characterized in that: A plug is installed at one end of the measuring tube to provide support for the push-pull rod, guide its movement, and prevent liquid leakage. The push-pull rod passes through the plug and is connected to the handle.

7. The liquid viscosity measurement auxiliary device according to claim 5, characterized in that: The sliding component has at least one rubber on its circumferential surface to enhance the sealing performance with the measuring tube.

8. The liquid viscosity measurement auxiliary device according to claim 6, characterized in that: The measuring tube is made of a transparent material and has a scale thereon reflecting the distance between the ultrasonic transducer and the reflecting end.

9. The liquid viscosity measurement auxiliary device according to claim 6, characterized in that: The PCB has a first interface for acquiring an excitation signal for stimulating the ultrasonic transducer from a signal generator, and a second interface for sending the collected ultrasonic signal to an oscilloscope and / or a computer; or The PCB is configured to generate an excitation signal for exciting the ultrasonic transducer, and convert the measured ultrasonic propagation velocity and signal attenuation into the viscosity of the liquid based on a mathematical model between the ultrasonic propagation velocity, signal attenuation and liquid viscosity.

10. A liquid viscosity measurement system, characterized in that: The device comprises: a liquid viscosity measurement auxiliary device as claimed in any one of claims 1 to 9; a signal generator for providing an excitation signal to the ultrasonic transducer of the device; and an oscilloscope for displaying the ultrasonic signal received by the ultrasonic transducer; Based on the mathematical model between ultrasonic wave propagation velocity, signal attenuation and liquid viscosity, and the ultrasonic wave propagation velocity and signal attenuation obtained by the device in the liquid, the liquid viscosity can be calculated.

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