Piezoelectric torsional vibration type industrial online viscosity measuring probe

Abstract

The invention discloses a piezoelectric torsional vibration type industrial online viscosity measuring probe which comprises a piezoelectric vibrator mounting shaft, a piezoelectric circular tube, a connecting part, a resonator consisting of a shaft and a sensing element, a flange in the middle and an adjusting circular ring at the rear end, eight pairs of spiral electrodes are wound on the outer surface of the piezoelectric circular tube, the rear end of the flange is provided with an axial circular ring hole and is combined with the piezoelectric circular tube, the rear end of the stainless steel shaft is provided with internal threads, an adjusting circular ring is fastened at the rear end of the stainless steel shaft through a screw, and a node of first-order torsional vibration is accurately adjusted to be located in the middle of the flange by changing the proportion of materials and adjusting the number of the circular ring. The invention designs the piezoelectric torsional vibration type online viscometer and provides a flexible node adjustment method, so that the problem of unstable nodes caused by material characteristic preparation difference and structural size machining tolerance is solved, and the actual working effect of the piezoelectric torsional vibration type online viscometer is ensured.

Description

Technical Field

[0001] The present invention relates to the field of measuring probes, in particular to a piezoelectric torsional vibration type industrial online viscosity measuring probe. Background Art

[0002] Viscosity, a key physical parameter of fluids, reflects the internal friction between molecules during relative motion. In industrial production and scientific research, such as energy and chemical engineering, biomedicine, and pharmaceuticals, rapid and accurate viscosity measurement is crucial for monitoring production processes, improving product quality, and advancing scientific development. In the transportation sector, the viscosity of engine fuel directly impacts its injection behavior and combustion quality. This influences the energy efficiency and environmental friendliness of vehicles like automobiles, airplanes, and ships, and also impacts the launch accuracy and stability of liquid-propellant rockets and missiles. Viscosity is a key criterion for evaluating the quality of mechanical lubricants. Online viscosity testing is crucial for predicting failures in moving mechanical components and ensuring their proper operation.

[0003] However, fluid viscosity cannot often be measured directly. It requires measuring related physical quantities and then calculating it using the corresponding equations. Currently, the most commonly used methods for measuring liquid viscosity include the capillary method, the falling ball method, the mechanical rotation method, and the mechanical vibration method. The most commonly used methods for measuring liquid viscosity include the capillary method, the falling ball method, the mechanical rotation method, and the mechanical vibration method. The capillary method measures the flow rate of the liquid in a capillary tube under a certain pressure difference and then converts it into a viscosity value; the falling ball method measures the speed of a metal ball in a liquid and then converts it into a viscosity value. The rotation method measures the resistance encountered by a probe driven by an electromagnetic motor when it rotates in a liquid, and then converts it to obtain the viscosity value. The mechanical vibration method measures the attenuation of the rotational vibration of an electromagnetically excited probe in a liquid and then converts it to obtain the viscosity value. While these traditional viscosity measurement devices can generally measure liquid viscosity with relative accuracy and reliability, most are only suitable for offline sample analysis. These devices are bulky and slow, making them incapable of rapid online continuous monitoring. Some methods that can be used for online measurement often suffer from limitations, such as complex measurement structures, high costs, and high sample requirements. This makes traditional viscosity measurement devices mostly suitable for offline measurements in laboratory settings, significantly limiting their application. In recent years, viscosity measurement devices based on the structural resonance of piezoelectric materials have been developed, enabling rapid online measurement of fluid viscosity. These devices possess considerable research value and broad development prospects. Piezoelectric viscosity measurement probes utilize the piezoelectric effect of piezoelectric materials to generate mechanical resonance. These probes then measure the changes in mechanical and electrical properties induced by the resonant structure in the fluid, converting them into corresponding viscosity values. Patent application CN105403485A, titled "A portable high-precision liquid viscosity measurement probe," consists of a piezoelectric fiber, a quartz rod, a metal tube, a metal sleeve, and a sealing ring. The measuring probe has a first-order torsional vibration mode. By rationally designing the dimensions of the piezoelectric fiber and the quartz rod, the first-order torsional vibration node of the resonator is located exactly at the circular base of the quartz rod.

[0004] These measuring probes require specific structural design and parameter adjustments to achieve node matching. However, the material properties and structural dimensions of the actual manufactured measuring probes differ from the designed parameters, resulting in actual nodes not being in the ideal position, significantly reducing the actual working performance of the measuring probes. Furthermore, the amplitude ratio between the probe end and the other end of these measuring probes is close to 1:1, which greatly inconveniences the installation of the measuring probes. Therefore, reliable structural design and flexible adjustment solutions remain challenges in the development of measuring probes. Summary of the Invention

[0005] To overcome the deficiencies in the aforementioned key technologies, the present invention provides a piezoelectric torsional vibration industrial online viscosity measurement probe. Through structural design, the node is maintained in an ideal position over a wide range. An adjustment structure is provided to precisely adjust the node position, thereby resolving the node instability problem caused by differences in material properties and structural dimensional processing tolerances.

[0006] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions:

[0007] A piezoelectric torsional vibration type industrial online viscosity measuring probe comprises a piezoelectric vibrator mounting shaft, a piezoelectric circular tube, and a shaft;

[0008] The front end of the piezoelectric vibrator mounting shaft is provided with a flange, and the rear end is provided with an internal thread, and the adjustment ring is fastened to the rear end of the piezoelectric vibrator mounting shaft by screws;

[0009] Eight pairs of spiral electrodes are spirally wound on the piezoelectric tube, an axial circular hole is provided at the rear end of the flange, and the front end of the piezoelectric tube is installed in the circular hole at the rear end of the flange;

[0010] The front end of the flange is provided with a connecting component, the rear end of the shaft is connected to the flange through the connecting component, and the front end of the shaft is provided with a sensing element;

[0011] The piezoelectric vibrator mounting shaft, the piezoelectric circular tube, the connecting component, the shaft, the inductive element and the adjusting ring constitute a resonator.

[0012] Further technology of the present invention:

[0013] Preferably, the connecting component, the shaft and the sensing element all have circular cross-sections.

[0014] Preferably, the flange is provided with four mounting holes.

[0015] Preferably, the piezoelectric circular tube is made of piezoelectric ceramic material, and the spiral electrode is made of conductive silver paste that is dried and solidified. The two constitute a piezoelectric vibrator as a vibration source.

[0016] Preferably, the number of the adjustment rings is set to N, where N≥1.

[0017] The beneficial effects of the present invention are:

[0018] The present invention applies piezoelectric torsional vibration to the detection of liquid viscosity, sets an adjustment ring, and provides a flexible node adjustment method to solve the node instability problem caused by differences in material properties and structural size processing tolerances. Based on the impedance method, an equivalent circuit is constructed to establish the relationship between electrical parameters and viscosity. It has a wide measurement range, high accuracy, simple structure, and easy installation and disassembly, and can be widely used in online measurement of equipment pipelines in industrial production processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0020] Figure 1 This is a schematic diagram of the structure of the measuring probe of the present invention;

[0021] Figure 2 This is a main sectional view of the measuring probe of the present invention;

[0022] Figure 3 Schematic diagram of the first-order torsional vibration mode of the measuring probe of the present invention;

[0023] Figure 4 This is a curve showing the relationship between the position of the first-order torsional vibration node and the number of adjustment rings in the present invention. DETAILED DESCRIPTION

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0025] like Figures 1 to 4 The piezoelectric torsional vibration type industrial online viscosity measurement probe shown includes a piezoelectric vibrator mounting shaft 1, a piezoelectric circular tube 2, a connecting component 3, a shaft 4, a sensing element 5, an adjustment ring 6, a flange 7, screws 8, and a mounting hole 9;

[0026] The front end of the piezoelectric vibrator mounting shaft is provided with a flange and the rear end is provided with an internal thread. The adjustment ring is fastened to the rear end of the piezoelectric vibrator mounting shaft by screws, which can increase the overall length and thus affect the node position;

[0027] Eight pairs of spiral electrodes are spirally wound on the piezoelectric tube, an axial circular hole is provided at the rear end of the flange, and the front end of the piezoelectric tube is installed in the circular hole at the rear end of the flange;

[0028] The front end of the flange is provided with a connecting component, the rear end of the shaft is connected to the flange through the connecting component, and the front end of the shaft is provided with a sensing element;

[0029] The piezoelectric vibrator mounting shaft, the piezoelectric circular tube, the connecting component, the shaft, the inductive element and the adjusting ring constitute a resonator.

[0030] The connecting parts, shaft and sensing element all have circular cross-sections, which are suitable for industrial pipeline scenarios. The flange is provided with four mounting holes 9 and can be installed in various industrial pipeline systems.

[0031] The piezoelectric tube is made of piezoelectric ceramic material, and the spiral electrode is made of conductive silver paste that is dried and solidified. The two constitute a piezoelectric vibrator as a vibration source, driving the entire structure to perform first-order torsional vibration.

[0032] like Figure 3 As shown in the figure, the resonator works in the first-order torsional vibration mode, and the node is at the middle position with zero amplitude. In this vibration mode, the amplitude ratio of the probe end to the piezoelectric end reaches 125:1.

[0033] like Figure 4 As shown in Figure 1, it is a curve showing the relationship between the first-order torsional vibration node position and the number of adjustment rings. The node position can be precisely controlled by adding the number of adjustment rings.

[0034] In the present invention, after the piezoelectric tube is polarized, the resonator composed of the piezoelectric tube and the stainless steel shaft generates first-order torsional vibration under the excitation of the AC voltage of the spiral electrode. Through reasonable design, its first-order vibration node is exactly located in the middle of the flange. When the probe is immersed in the liquid to be tested and contacts the liquid to be tested, the vibration characteristics will change. The electrical admittance frequency response curve of the resonator is measured by the spiral electrode of the piezoelectric tube, and the viscosity of the liquid to be tested can be calculated.

[0035] The above content is merely an example and explanation of the structure of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in a similar manner. As long as they do not deviate from the structure of the invention or exceed the scope defined by the claims, they should all fall within the scope of protection of the present invention.

Claims

1. A piezoelectric torsional vibration industrial online viscosity measurement probe, characterized by: It includes a piezoelectric vibrator mounting shaft, a piezoelectric round tube, and a shaft; The front end of the piezoelectric vibrator mounting shaft is provided with a flange, and the rear end is provided with an internal thread, and the adjustment ring is fastened to the rear end of the piezoelectric vibrator mounting shaft by screws; Eight pairs of spiral electrodes are spirally wound on the piezoelectric tube, an axial circular hole is provided at the rear end of the flange, and the front end of the piezoelectric tube is installed in the circular hole at the rear end of the flange; The front end of the flange is provided with a connecting component, the rear end of the shaft is connected to the flange through the connecting component, and the front end of the shaft is provided with a sensing element; The piezoelectric vibrator mounting shaft, the piezoelectric circular tube, the connecting component, the shaft, the inductive element and the adjusting ring constitute a resonator.

2. The piezoelectric torsional vibration industrial online viscosity measurement probe according to claim 1, characterized in that: The connecting part, the shaft and the sensing element all have circular cross sections.

3. The piezoelectric torsional vibration industrial online viscosity measurement probe according to claim 1, characterized in that: The flange is provided with four mounting holes.

4. The piezoelectric torsional vibration industrial online viscosity measurement probe according to claim 1, characterized in that: The piezoelectric circular tube is made of piezoelectric ceramic material, and the spiral electrode is made of conductive silver paste that is dried and solidified. The two constitute a piezoelectric vibrator as a vibration source.

5. The piezoelectric torsional vibration industrial online viscosity measurement probe according to claim 1, characterized in that: The number of the adjustment rings is set to N, where N≥1.

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