Hydraulic system oil leakage monitoring method

Abstract

The invention provides an oil leakage monitoring method for a hydraulic system, and belongs to the technical field of hydraulic control. The method comprises the steps of collecting oil tank liquid level data of the hydraulic system at a preset frequency; calculating the oil tank liquid level fluctuation and the oil tank liquid level change rate of the hydraulic system in the preset period; when the oil tank liquid level fluctuation exceeds a preset oil tank liquid level normal fluctuation range, whether the oil tank liquid level drops to the lowest oil tank liquid level or not is judged; and if the liquid level of the oil tank drops to the lowest liquid level of the oil tank and does not rise to the preset normal fluctuation range of the liquid level of the oil tank within the preset time, a sudden oil leakage instruction of the hydraulic system is sent out. If the oil tank liquid level does not drop to the lowest oil tank liquid level, whether the oil tank liquid level change rate exceeds a preset oil tank liquid level change rate threshold value or not is judged, and if yes, a hydraulic system oil leakage early warning instruction is sent out. According to the method, sudden oil leakage of the hydraulic system can be found in time, false alarms caused by normal fluctuation of the hydraulic system are avoided, meanwhile, small-flow leakage of the hydraulic system can be found, and the false alarm rate is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydraulic control, in particular to a hydraulic system oil leakage monitoring method. BACKGROUND

[0002] Hydraulic equipment has the characteristics of strong carrying capacity, stable operation, high response speed, etc., and is widely used in the field of steel rolling. However, in the actual production process, due to the wide distribution of hydraulic pipelines and the harsh working conditions, the hydraulic systems of various equipment all have more or less oil leakage. Therefore, it is of great economic, safety and environmental significance to establish a high-precision oil tank level measurement and alarm system to timely detect the oil leakage of hydraulic equipment and take appropriate maintenance measures.

[0003] The existing oil leakage alarm generally uses monitoring the oil tank level fluctuation of the hydraulic system to alarm. Specifically, an oil tank level switch is set on the main oil tank level gauge, and an oil leakage alarm is sent when the main oil tank level drops to the low oil tank level of the oil tank level switch. Although this method can detect and alarm, in actual work, due to the normal fluctuation in the normal operation of the hydraulic system, in order to avoid false alarms caused by normal fluctuations of the oil tank level, the oil tank level switch is generally installed below the minimum value of the normal fluctuation of the oil tank level, and a certain safety margin is reserved, which leads to delayed detection and alarm of oil leakage. When oil leakage is detected, the hydraulic oil in the oil tank may have been completely leaked, and the leakage amount is often as high as 60%-70% of the oil tank volume, and the leaked hydraulic oil also pollutes the environment. In addition, since the alarm signal of the oil tank level switch is a Boolean quantity, it cannot accurately monitor the oil tank level and cannot timely detect the decrease of the oil tank level caused by small leaks, resulting in serious delay of the alarm and the inability of the hydraulic equipment to operate normally.

[0004] Therefore, there is a need for a hydraulic system oil leakage monitoring method that can detect small amounts of oil leakage without increasing the probability of false alarms. SUMMARY

[0005] Therefore, the present application provides a hydraulic system oil leakage monitoring method, which accurately judges whether the hydraulic system has oil leakage by accurately monitoring the oil tank level, analyzing the oil tank level data and data model.

[0006] Therefore, the present application provides the following technical solutions: A hydraulic system oil leakage monitoring method, comprising: collecting oil tank level data of the hydraulic system at a preset frequency; calculating the oil tank level fluctuation and the oil tank level change rate of the hydraulic system within a preset period; when the oil tank level fluctuation exceeds the preset normal oil tank level fluctuation range, judging whether the oil tank level has dropped to the minimum oil tank level; If the oil tank level drops to the minimum oil tank level, and does not rise to the preset oil tank level normal fluctuation range within the preset time, an oil leakage of the hydraulic system emergency instruction is issued.

[0007] Further, if the oil tank level does not drop to the minimum oil tank level, it is judged whether the oil tank level change rate exceeds the preset oil tank level change rate threshold, and if so, an oil leakage of the hydraulic system early warning instruction is issued.

[0008] Further, the preset oil tank level normal fluctuation range is output by inputting the historical data of the hydraulic system into the K nearest neighbor model.

[0009] Further, the historical data includes all the oil tank level data of the hydraulic system in the past three years.

[0010] Further, the historical data is updated every three months based on newly collected data; and the updated preset oil tank level normal fluctuation range is output by the K nearest neighbor model according to the updated historical data.

[0011] Further, the oil tank level change rate includes:

[0012] wherein, represents a preset period determined based on a preset sampling frequency, represents the oil tank level fluctuation in the preset period.

[0013] Advantages and positive effects of the present application: The method can accurately monitor the oil tank level in real time, timely find the sudden oil leakage of the hydraulic system, avoid false alarms caused by normal fluctuations of the hydraulic system, and minimize economic losses and environmental pollution caused by oil leakage.

[0014] The method compares the change rate of the continuous decrease of the oil tank level in a period of time with the change rate of the decrease of the oil tank level caused by normal loss of the hydraulic system, finds the small flow leakage of the hydraulic system, and reduces the false alarm rate. BRIEF DESCRIPTION OF DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0016] Figure 1 The flow chart of the hydraulic system oil leakage monitoring method in Embodiment 1 of the present application; Figure 2 Figure 1 is a schematic diagram of data flow of the hydraulic system oil leakage monitoring method in the embodiment 2 of the present application; Figure 3 Figure 2 is a tank liquid level curve diagram of the hydraulic system oil leakage in the embodiment 2 of the present application. DETAILED DESCRIPTION

[0017] In order to make the person skilled in the art better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by the person skilled in the art without creative labor should belong to the scope of protection of the present application.

[0018] It should be noted that the terms "first", "second" and the like in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or a chronological sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0019] The present application provides a hydraulic system oil leakage monitoring method, which collects tank liquid level data of the hydraulic system at a preset frequency; calculates the tank liquid level fluctuation and the tank liquid level change rate of the hydraulic system within a preset period; when the tank liquid level fluctuation exceeds the preset tank liquid level normal fluctuation range, judges whether the tank liquid level has dropped to the minimum tank liquid level; if the tank liquid level has dropped to the minimum tank liquid level and has not risen to the preset tank liquid level normal fluctuation range within a preset time, issues a hydraulic system sudden oil leakage instruction. If the tank liquid level has not dropped to the minimum tank liquid level, judges whether the tank liquid level change rate exceeds the preset tank liquid level change rate threshold, and if it exceeds, issues a hydraulic system oil leakage warning instruction.

[0020] Embodiment 1 In conjunction with Figure 1 As shown in the figure, a hydraulic system oil leakage intelligent alarm method comprises: S1, installing a digital tank liquid level sensor in the hydraulic system tank, converting the tank liquid level signal into a 4-20 mA signal, connecting the signal cable to the PLC system to read the tank liquid level data; S2, acquiring the hydraulic system oil tank liquid level data from the PLC system through the data acquisition machine, and reading the oil tank liquid level data by the leakage alarm system through the Kafka consumption event, which is used for the hydraulic dynamic monitoring and subsequent alarm analysis of the system; S3, monitoring the oil tank liquid level data in real time, and when the oil tank liquid level fluctuation is greater than the preset oil tank liquid level normal fluctuation range output by the K nearest neighbor model inputting the historical data of the hydraulic system: 1) if the oil tank liquid level reaches the lowest point and the oil tank liquid level does not rise to the normal fluctuation value within the preset time, the hydraulic system has a sudden and large leakage.

[0021] 2) if the oil tank liquid level does not reach the lowest point, a dynamic curve of the oil tank liquid level-time is established, and the height change of the oil tank liquid level within a preset period Δt is calculated according to the preset period Δt , and the oil tank liquid level change rate within the preset period is calculated as follows:

[0022] wherein, represents the preset period determined based on the preset sampling frequency, represents the oil tank liquid level fluctuation within the preset period.

[0023] The real-time calculated oil tank liquid level change rate is compared with the preset change rate threshold , and if , the oil tank hydraulic pressure drops at a speed greater than that caused by normal loss, and the system has a leakage.

[0024] In this embodiment, the historical data includes all the oil tank liquid level data of the hydraulic system in the past three years.

[0025] In this embodiment, the historical data is updated based on newly collected data every three months, and the updated preset oil tank liquid level normal fluctuation range is output according to the updated historical data through the K nearest neighbor model.

[0026] Embodiment 2 The embodiment provides a hydraulic system leakage intelligent alarm system, which comprises: S01, installing a digital oil tank liquid level sensor on the hydraulic system oil tank, converting the oil tank liquid level signal into a 4-20 mA signal, and connecting the signal cable to the PLC system to read the oil tank liquid level data; S02, acquiring the hydraulic system oil tank liquid level data from the PLC system through the data acquisition machine, and reading the oil tank liquid level data by the leakage alarm system through the Kafka consumption event, which is used for the hydraulic dynamic monitoring and subsequent alarm analysis of the system; S03, the system monitors the oil tank level data in real time, when the oil tank level fluctuation is greater than the preset oil tank level normal fluctuation range determined by big data analysis, and the oil tank level does not rise within the preset time after reaching the lowest point, it is judged that the hydraulic system has a sudden, large leakage; S04, a dynamic curve related to the oil tank level and time is established, and the oil tank level change rate in the preset time period is calculated according to the height change of the oil tank level in the preset period, which is expressed by the formula:

[0027] Among them, represents the oil tank level change rate, represents the preset period, represents the height change of the oil tank level in the preset period, that is, the oil tank level fluctuation.

[0028] S05, preset change rate threshold, when the real-time oil tank level change rate is greater than the preset change rate threshold , the oil tank hydraulic pressure drops faster than the oil tank level drop caused by normal loss, and the system has a leakage.

[0029] As Figure 3 shown, the oil tank level sensor converts the oil tank level into a 4-20 mA signal, which is connected to the PLC system through a signal cable. After the IBA system obtains the oil tank level data from the PLC system, it stores the filtered oil tank level data into the Influxdb time series database through Kafka consumption events. The system tool calls the oil leakage judgment rule of the rule engine to monitor the oil tank level data in real time. When the system determines that the hydraulic system has a leakage, the alarm information is sent to the system terminal for display, and the alarm information is sent to the relational database for storage for subsequent query. The rule model is optimized through self-learning of oil leakage cases, which improves the accuracy of the model. At the same time, the oil tank level data is directly sent to the front end for display by the Influxdb time series database.

[0030] The oil tank level curve of the AGC hydraulic system of a certain rolling mill is shown in Figure 3 , the preset oil tank level normal fluctuation range H, at a certain time, the oil tank level fluctuation reaches h, which exceeds H, and the oil tank level does not recover to the normal fluctuation range within the preset time, then the system has a sudden, large leakage.

[0031] This method can not only determine the sudden, large leakage of the system through real-time monitoring of the oil tank level and big data analysis, but also can determine the slight abnormal leakage of the system through mathematical model research and judgment.

[0032] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit the present application; although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions recorded in the above embodiments can be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for detecting oil leakage in a hydraulic system, characterized in that, include: The hydraulic system's oil tank level data is collected at a preset frequency; Calculate the fluctuation and rate of change of oil level in the hydraulic system's tank within a preset period; When the fluctuation of the oil tank level exceeds the preset normal fluctuation range of the oil tank level, it is determined whether the oil tank level has dropped to the minimum oil tank level. If the oil tank level drops to the minimum oil tank level and fails to rise back to the preset normal fluctuation range of the oil tank level within a preset time, a hydraulic system emergency oil leakage command will be issued.

2. The method according to claim 1, characterized in that, Also includes: If the oil tank level does not drop to the minimum oil tank level, it is determined whether the oil tank level change rate exceeds the preset oil tank level change rate threshold. If it does, a hydraulic system oil leakage warning command is issued.

3. The method according to claim 1, characterized in that, The preset normal fluctuation range of the oil tank level is output by inputting historical data of the hydraulic system through the K-nearest neighbor model.

4. The method according to claim 3, characterized in that, The historical data includes all tank level data for the hydraulic system over the past three years.

5. The method according to claim 3, characterized in that, Historical data is updated every three months based on newly collected data; Based on the updated historical data, the updated preset normal fluctuation range of the oil tank level is output through the K nearest neighbor model.

6. The method according to claim 1, characterized in that, The rate of change of oil tank level includes: in, This indicates a preset period determined based on a preset sampling frequency. This indicates the fluctuation of the oil tank level within a preset period.

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