Created on:2021-12-21 13:40

Overview of fault finding of hydraulic equipment

Overview of fault finding of hydraulic equipment

Hydraulic transmission system is more and more widely used in various fields because of its unique advantages, such as wide process adaptability, excellent control performance and low cost. However, due to the unstable quality of components and accessories objectively and improper subjective use and maintenance, and all components and working fluids in the system work in a closed oil circuit, it is not as intuitive as mechanical equipment or electrical equipment, and various parameters can be easily measured by various detection instruments. In hydraulic equipment, only a limited number of pressure gauges and flow meters are used to indicate the working parameters of some parts of the system, while other parameters are difficult to measure, and there are many possible causes of general faults, which brings some difficulties to the fault diagnosis of hydraulic system.

At the production site, due to the constraints of production plan and technical conditions, fault diagnosis personnel are required to diagnose the faults of hydraulic equipment accurately, simply and efficiently; The maintenance personnel are required to make use of the existing information and on-site technical conditions to reduce the disassembly workload as much as possible, save maintenance man hours and expenses, and use the simplest technical means to accurately find out the fault location and the cause of the fault in the shortest possible time and repair it, so as to restore the normal operation of the system, and strive not to have the same fault in the future.

At present, the traditional method to find the fault of hydraulic system is logical analysis and gradual approximation diagnosis. The basic idea of this method is comprehensive analysis and conditional judgment. That is, the maintenance personnel judge the cause of the fault by experience through observation, listening, touch, simple test and understanding of the hydraulic system. When the hydraulic system fails, there are many possible causes of the failure. The logical algebra method is used to list the possible fault causes, and then make logical judgment one by one according to the principle of easy before difficult, and approach one by one, so as to finally find out the fault causes and specific conditions causing the fault.

This method requires maintenance personnel to have basic knowledge of hydraulic system and strong analysis ability in the process of fault diagnosis, so as to ensure the efficiency and accuracy of diagnosis. However, the diagnosis process is cumbersome, requires a lot of inspection and verification, and can only be analyzed qualitatively, and the fault cause of diagnosis is not accurate enough. In order to reduce the blindness and experience of system fault detection and the workload of disassembly and assembly, the traditional fault diagnosis method is far from meeting the requirements of modern hydraulic system.

In recent years, with the development of hydraulic system towards large-scale, continuous production and automatic control, a variety of modern fault diagnosis methods have appeared. For example, ferrography technology can diagnose the quantity, shape, size, composition and distribution law of various wear particles separated from the oil, and timely and accurately judge the wear position, form and degree of components in the system; Moreover, it can carry out quantitative pollution analysis and evaluation of hydraulic oil, so as to achieve on-line detection and fault prevention. Another example is the expert diagnosis system based on artificial intelligence, which inputs the fault phenomenon into the computer through the man-machine interface by imitating the problem-solving method of experienced experts in a certain field. The computer can calculate the cause of the fault according to the input phenomenon and the knowledge in the knowledge base, and then output the cause through the man-machine interface, And propose maintenance scheme or preventive measures. These methods bring broad prospects for hydraulic system fault diagnosis and lay a foundation for hydraulic system fault diagnosis automation. However, most of these methods need expensive detection equipment and complex sensing control system and computer processing system, and some methods are difficult to study. At present, it is not suitable for on-site promotion.

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