Pressure vessel liquid level measuring device based on vibration detection

Abstract

The invention discloses a pressure vessel liquid level measuring device based on vibration detection, which comprises two vibration sensors arranged on the outer wall of a vessel at intervals along the height direction of the vessel, the two vibration sensors are electrically connected with a liquid level transmitter through an electrical wiring port, and the liquid level transmitter is electrically connected with a control system / control center. According to the device, non-contact liquid level measurement is achieved according to the characteristic relation between the vibration frequency generated when a medium in the pressure container is knocked on the outer wall in the height direction of the container and the liquid level of the medium in the container, and the problem that the liquid level of the pressure container is difficult to measure under the severe working conditions of high temperature, high pressure, strong acid, strong alkali and the like is solved; the influence of the working environment on the liquid level measuring device is greatly reduced, the service life of the liquid level measuring device is prolonged, and the cost of the liquid level measuring device can be remarkably reduced; the device is easy to operate, convenient to use and free of physical harm in the operation process, and liquid level measurement of the pressure vessel is more efficient, reliable, safer and more accurate, and saves energy.

Description

Technical Field

[0001] The invention relates to a liquid level measuring device, in particular to a pressure vessel liquid level measuring device based on vibration detection. Background Art

[0002] Automated instruments are the premise of scientific progress and the basis of production activities. When the scope of human activities exceeds the limits of sensory organs, it is necessary to use instrumentation technology to measure and obtain information technology for data information. The automated instrumentation industry is the source of the information industry. In the production process, automated instruments detect, transmit, display, control and execute the information of the measured object, thereby realizing management and decision-making. With the rapid development of the national industry, the requirements for the level and accuracy of automated control in industrial production operations are also rapidly increasing. Liquid level control is an important link in the control of the field of industrial automation. It occupies a pivotal position in many industrial fields and plays an irreplaceable role in ensuring production safety, improving production efficiency, optimizing management decisions, and achieving energy conservation and emission reduction goals. It is mainly reflected in the following aspects: First of all, accurate measurement and control of liquid level is essential to ensure safe and stable operation of the production process. In many industrial processes, such as chemical, petroleum, and pharmaceutical, excessively high or low liquid levels may cause serious accidents, such as leakage and explosion. Through accurate liquid level measurement and control, process parameters can be adjusted in time to avoid dangerous situations.

[0003] Secondly, liquid level data is the key basis for optimizing production processes and improving production efficiency. By real-time monitoring of liquid level changes, the feeding and discharging speeds of materials can be accurately controlled, and the production process can be automated and precise, thereby reducing resource waste and improving production efficiency and product quality.

[0004] Furthermore, liquid level data is an important basis for realizing automated production and intelligent management. With the help of real-time data collected by liquid level sensors and related instruments, combined with advanced control systems, automated adjustment and remote monitoring of the production process can be achieved, improving the refinement and intelligence of production management.

[0005] In addition, liquid level information also plays an important role in energy conservation and emission reduction. Reasonable control of liquid level can avoid unnecessary energy consumption and material loss, reduce production costs, and meet the requirements of sustainable development.

[0006] In view of the importance of the above-mentioned liquid level measurement, combined with the difficulties and pain points of liquid level measurement in various sub-sectors of industrial production (such as pressure vessels in special equipment), a liquid level measurement device suitable for actual industrial production and capable of solving liquid level measurement problems encountered in practical applications is developed.

[0007] A pressure vessel refers to a closed device that contains gas or liquid and bears a certain pressure. Pressure vessels are widely used in industrial production, such as non-ferrous metallurgy, petrochemicals, energy, pharmaceuticals and other fields. The liquid level of a pressure vessel is also a very important process parameter during its use, and it plays a vital role in the operation status, equipment safety and production stability of the entire system. In view of the fact that there are harsh environments such as high temperature, high pressure, strong acid and strong alkali inside the pressure vessel, when the direct contact method is used to measure the liquid level, the requirements for the liquid contact material of the instrument are very high. It must not only be resistant to high temperature and high pressure, but also have specific anti-corrosion properties for the corrosive characteristics of the medium in the pressure vessel. Not to mention whether it can be achieved, even if a liquid level detection instrument that can be used in such an application scenario is manufactured, its cost is suddenly increased to a prohibitive level. Therefore, for the detection of pressure vessels, most non-contact measurement methods are used. At present, the commonly used non-contact liquid level measurement instruments for pressure vessels are ultrasonic level gauges, radar level gauges, and nuclear radiation level gauges. Ultrasonic level gauges and radar level gauges use ultrasonic propagation characteristics and microwave radar technology for measurement, while nuclear radiation level gauges use the principle that the intensity of nuclear radiation passing through materials varies with the thickness of the material layer. Ultrasonic level gauges and radar level gauges have certain limitations in applications such as foam, large level fluctuations, high temperature, and high pressure; and nuclear radiation level gauges are not only relatively expensive, but also involve the radioactivity of the source, which must be registered and approved according to laws and regulations. There are also various rules such as the need to wear special protective clothing during use, which makes the cost of use too high, causing many inconveniences.

[0008] The inventor team of this application has previously developed a pressure vessel liquid level measurement device based on acoustic wave detection and applied for relevant patents. The liquid level measurement device uses the characteristic relationship between the acoustic waves generated by the medium in the pressure vessel during the flow process and the liquid level of the medium in the container. By detecting the acoustic waves and comparing the acoustic wave frequency-liquid level height characteristic curve table that has been experimentally developed, it can realize non-contact real-time liquid level monitoring of the container medium during production and operation, and then indirectly measure the liquid level of the medium in the pressure vessel. However, when the device is used in a noisy environment or when the flow speed of the medium in the container is slow, the measurement results are not accurate enough and may be biased. Summary of the invention

[0009] The purpose of the present invention is to provide a pressure vessel liquid level measuring device based on vibration detection, which can effectively and real-timely reflect the pressure vessel liquid level height, and the present invention has a simple and reliable structure and is easy to maintain.

[0010] The technical solution of the present invention is a pressure vessel liquid level measuring device based on vibration detection, comprising two vibration sensors arranged on the outer wall of the container at intervals along the height direction of the container, the two vibration sensors are electrically connected to the liquid level transmitter through an electrical wiring port, and the liquid level transmitter is electrically connected to the control system / control center.

[0011] In the aforementioned pressure vessel liquid level measuring device based on vibration detection, a protective cover is provided on the outside of each vibration sensor.

[0012] In the aforementioned pressure vessel liquid level measuring device based on vibration detection, the vibration sensor includes a mounting bracket fixed on the outer wall of the container, and a retractable knocker, a vibration sensitive element and a vibration signal processor are arranged on the mounting bracket. The vibration sensitive element is fixed on the outer wall of the container, and the vibration sensitive element and the vibration signal processor are connected via internal components. The vibration signal processor is electrically connected to the liquid level transmitter through an electrical wiring port.

[0013] In the aforementioned pressure vessel liquid level measuring device based on vibration detection, two vibration sensors are respectively arranged near the top and bottom positions, one is arranged below the medium low alarm liquid level, and the other is arranged above the medium high alarm liquid level.

[0014] Beneficial effects of the invention: Compared with the prior art, the device of the invention has the following advantages: ① Non-contact measurement of liquid level has a wider range of applications, has no special requirements for the medium itself, and is not affected by high temperature, high pressure and corrosiveness of the medium in the container. It is especially suitable for the situation where the medium in the container coexists with gas / liquid, high temperature, high pressure and corrosiveness; ② The principle and structure should be simple, the components used should be common and universal, and the cost should be low; ③ There are no physical hazards such as electromagnetic and nuclear radiation that are harmful to the human body during the liquid level measurement process, with low cost and high safety performance; ④ Utilize the characteristic relationship between the vibration frequency generated by the pressure vessel medium during the active knocking process and the liquid level of the medium in the container, and obtain the special vibration frequency of the pressure vessel and the liquid level of the medium therein by adjusting the knocking intensity of the knocker, which can not only realize real-time monitoring, but also make the measurement accurate.

[0015] In summary, the device of the present invention realizes non-contact liquid level measurement based on the characteristic relationship between the vibration frequency generated when the medium in the pressure vessel is knocked on the outer wall along the height direction of the container and the liquid level of the medium in the container. It not only solves the problem that the liquid level of the pressure vessel is difficult to measure under adverse working conditions such as high temperature, high pressure, strong acid, strong alkali, etc., but also greatly reduces the impact of the working environment on the liquid level measuring device, extends the service life of the liquid level measuring device, and can significantly reduce the cost of the liquid level measuring device. The device of the present invention is simple to operate, easy to use, and has no physical hazards during operation, making the liquid level measurement of the pressure vessel more efficient, reliable, energy-saving, safe, and accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the present invention; Figure 2 This is a schematic diagram of the structure of the vibration sensor.

[0017] Figure numerals: 1-vibration sensor, 2-protective cover, 3-liquid level transmitter, 4-control system / control center, 5-mounting bracket, 6-retractable knocker, 7-vibration sensitive element, 8-vibration signal processor, 9-electrical wiring port. DETAILED DESCRIPTION

[0018] The present invention is further described below in conjunction with the accompanying drawings and embodiments, but they are not intended to limit the present invention.

[0019] An embodiment of the present invention: A pressure vessel liquid level measuring device based on vibration detection includes two vibration sensors 1 arranged on the outer wall of the container at intervals along the height direction of the container. The two vibration sensors 1 are electrically connected to the liquid level transmitter 3 through an electrical wiring port 9, and the liquid level transmitter 3 is further electrically connected to the control system / control center 4.

[0020] The device of the present invention is designed based on the following principle: utilizing the characteristic relationship between the vibration frequency generated by the pressure vessel medium in the process of actively knocking on the outer wall of the container and the liquid level of the medium in the container, by detecting the vibration and comparing it with the vibration frequency-liquid level height characteristic curve table that has been experimentally developed, during production operation, non-contact real-time monitoring of the liquid level of the medium in the container is achieved, and then the medium liquid level in the pressure vessel is indirectly measured.

[0021] By arranging two vibration sensors 1 on the side of the pressure vessel (one is arranged below the medium liquid level, and the other is arranged above the medium liquid level, and the specific installation position can be determined according to the heights of the normal liquid level, the low alarm liquid level, and the high alarm liquid level of the pressure vessel), the vibration sensor 1 measures the vibration generated by the pressure vessel medium in the process of actively knocking on the outer wall of the container, and transmits the vibration data to the liquid level transmitter 3. The vibration data is automatically matched with the vibration frequency-liquid level standard characteristic curve table that has been experimentally developed in the liquid level transmitter 3, and the two liquid level signals are processed to obtain their weighted average, so as to measure the pressure vessel liquid level, realize non-contact real-time monitoring of the internal medium liquid level of the pressure vessel when the pressure vessel is running, and the liquid level signal can be remotely transmitted to the control system / control center 4.

[0022] The reason why two vibration frequency sensors 1 are needed is that the pressure vessel tank is high, the distance is too long, and the height of the medium liquid level in the pressure vessel has an impact on vibration transmission. If you want to ensure high detection accuracy, only one vibration sensor 1 is set, it is necessary to improve the sensitivity and accuracy of the vibration sensor 1, which is costly, and the sensor also has a certain distance requirement for obtaining vibration. If the number of vibration sensors 1 is increased, the requirements for vibration sensors 1 will not be harsh, and the vibration frequency below and above the medium liquid level in the pressure vessel can be measured, so that the applicability and measurement accuracy of the detection device will be better.

[0023] A protective cover 2 is provided on the outside of each vibration sensor 1 to prevent excessive influence of the external environment when collecting the vibration generated by the internal medium of the pressure vessel actively knocking on the outer wall of the container.

[0024] The vibration sensor 1 includes a mounting bracket 5 fixed on the outer wall of the container, and a retractable knocker 6, a vibration sensitive element 7 and a vibration signal processor 8 are arranged on the mounting bracket 5. The vibration sensitive element 7 is fixed on the outer wall of the container, and the vibration sensitive element 7 and the vibration signal processor 8 are connected through internal components. The vibration signal processor 8 is electrically connected to the liquid level transmitter 3 through an electrical connection port 9. The retractable knocker 6 is retracted to realize the knocking of the outer wall of the container, and the vibration generated by the internal medium of the pressure vessel in the process of actively knocking the outer wall of the container is collected through the vibration sensitive element 7. The collected vibration signal is processed by the vibration signal processor 8 and then transmitted to the liquid level transmitter 3.

[0025] Two vibration sensors 1 are respectively arranged near the top and bottom positions, one is arranged below the medium low alarm liquid level, and the other is arranged above the medium high alarm liquid level. By installing two vibration sensors 1 below and above the medium level in the pressure vessel, high measurement accuracy and precision are guaranteed.

[0026] The specific implementation features of the present invention are as follows: ① The bottom of the vibration sensor 1 needs to be customized according to the external shape characteristics of the installed pressure vessel to ensure that the bottom is closely fitted to the outside of the equipment; ② The specific installation positions of the two vibration sensors 1 must be determined according to the heights of the normal liquid level, low alarm liquid level, and high alarm liquid level of the pressure vessel (such as Figure 1 As shown); ③ The liquid level transmitter 3 has the comprehensive function of filtering out external noise and invalid vibration, reading the vibration frequency corresponding to the liquid level within a specific range, and transmitting the output liquid level; ④ It has standard electronic components: the power supply adopts the civilian 220V standard AC power supply, and outputs 4~20mA standard signal to the outside.

[0027] Taking the flash tank in the dissolution workshop of the Bayer alumina plant as an example, the flash tank is a double elliptical head tank with a diameter of about 5m, a straight section height of about 7m, a working pressure of about 3.4Mpa, and a working temperature of about 270℃. The medium in the tank is red mud slurry, the liquid part is sodium aluminate solution (caustic soda concentration Nk=200~240g / L), and the solid part is red mud, and the two are mixed evenly. The sodium aluminate solution in the flash tank flashes out alkaline vapor, so the container is in a state where gas, liquid and solid coexist. Usually, nuclear radiation level gauges are used for measurement, which is not only expensive, but also requires the installation of nuclear sources due to the presence of nuclear radiation. In order to ensure safety, the operation is complicated and the approval procedures are cumbersome. After the liquid level measurement device is set up, the real-time liquid level measurement function can be realized, the measurement accuracy reaches ±2%, and it is low in price, easy to operate and safe.

Claims

1. A pressure vessel liquid level measuring device based on vibration detection, characterized in that: The invention comprises two vibration sensors (1) arranged on the outer wall of the container at intervals along the height direction thereof. The two vibration sensors (1) are electrically connected to a liquid level transmitter (3) via an electrical wiring port (9), and the liquid level transmitter (3) is further electrically connected to a control system / control center (4).

2. A pressure vessel liquid level measuring device based on vibration detection according to claim 1, characterized in that: A protective cover (2) is arranged on the outside of each vibration sensor (1).

3. The pressure vessel liquid level measuring device based on vibration detection according to claim 1 is characterized in that: The vibration sensor (1) comprises a mounting bracket (5) fixed on the outer wall of a container, a retractable knocker (6), a vibration sensitive element (7) and a vibration signal processor (8) are arranged on the mounting bracket (5), the vibration sensitive element (7) is fixed on the outer wall of the container, the vibration sensitive element (7) and the vibration signal processor (8) are connected via an internal component, and the vibration signal processor (8) is electrically connected to the liquid level transmitter (3) via an electrical wiring port (9).

4. The pressure vessel liquid level measuring device based on vibration detection according to claim 1 is characterized in that: Two vibration sensors (1) are respectively arranged near the top and bottom positions, one is arranged below the medium low alarm liquid level, and the other is arranged above the medium high alarm liquid level.

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