How should the maintenance and inspection of original imported Fujioka piston pumps be carried out?

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Among the complete sets of equipment introduced into the metallurgy industry, the hydraulic stations are mostly equipped with high-pressure, high-flow hydraulic piston pump units manufactured by European and American companies such as Japanese Fubuki and American Parker, as well as Japanese manufacturers. After the equipment was put into use, due to the lack of corresponding technical manuals for hydraulic piston pumps at the time of introduction, there was no understanding of the methods for monitoring the pump’s operational status, its maintenance procedures, or its service life (service life refers to the operational period specified during the equipment’s design). Therefore, some equipment managers in domestic companies believe that foreign hydraulic piston pumps have superior performance and a longer service life; as long as the hydraulic pump is operating and the system pressure is maintained, there is no need for maintenance. Moreover, appropriate rules and regulations for on-site inspection of hydraulic pumps have not been established, which leads to misunderstandings in the management of imported hydraulic piston pumps. Like mechanical equipment, imported hydraulic piston pumps also have a service life. The length of the service life depends on the cleanliness of the hydraulic fluid, as well as proper monitoring, maintenance, and care during equipment operation. Online monitoring, diagnosis, and predictive maintenance of hydraulic piston pumps: At the beginning of this century, relying on advanced condition monitoring and diagnostic instruments such as modern electronic testing techniques and computer analysis, as well as technologies like ultrasonic leakage detection, infrared temperature measurement, and wavelet analysis for pump bearings, regular inspections and diagnoses were carried out on pumps in operation. Based on the fault signals collected, curves showing the pumps’ performance while in use were generated, and evaluation reports were prepared. Decide whether to repair the pump based on the monitoring results. This enables the determination of the optimal maintenance interval for the pump, avoiding excessive maintenance in preventive maintenance and thereby reducing costs. It extends the service life of the pump and reduces losses due to failures and downtime. Replace the previous regular maintenance system with a condition-based monitoring and maintenance system. It also replaces the old manual inspection methods, such as feeling the temperature and vibration of the pump’s casing with the hand, and listening to whether the noise generated by the pump during operation is louder than before. In particular, it refers to skill-based maintenance based on individual experience with equipment inspections, rather than maintenance that relies on advanced testing and scientific standards for diagnosis. 2. Monitoring and diagnostic devices are the means for fault diagnosis. Fault diagnosis methods can be divided into two main categories: portable and simple diagnosis, and online and precise diagnosis. The main indicators of hydraulic pump failure include reduced pressure, decreased flow rate, rising temperature, variable speed timeout, increased noise and vibration, and excessive leakage within the pump. When testing different parameters, different measurement methods, tools, and instruments should be selected based on the actual conditions reflected by the hydraulic pump, the on-site conditions, and the required accuracy levels. The principle of the hydraulic pump fault diagnostic device developed in Japan is to conduct inspections using vibration diagnosis methods, with the microcomputer analyzing the data and providing forecasts of potential faults. It is possible to directly detect internal wear of the pump from the outside of the pump at a relatively fast pace, thereby effectively preventing pump failures and improving the reliability of the main unit. Pump testing can also involve using a hydraulic tester to measure the overall efficiency of the pump. A hydraulic tester consists of a flow meter, pressure gauge, and thermometer; it can be connected to the pump’s discharge outlet, and by adjusting the various functions of the instrument, the flow rate at different pressure levels at the pump’s discharge outlet can be measured, thereby allowing for the creation of a curve showing the pump’s overall efficiency. The pump must be taken offline for repair when its overall efficiency drops to 72%. The tester is connected to the pump’s oil drain port to measure the internal leakage of the pump. The leakage rate of a pump varies over time as it is used. By measuring the changes in leakage rate over a fixed period, it is possible to determine how the pump’s performance affects the proper operation of the system. The curve that shows the variation in leakage rate over time is known as a status curve; this curve can be used as an indicator of the pump’s operating condition, and it helps in predicting failures and determining the appropriate time for maintenance. Drawing and analysis of the internal leakage curve of the pump. Plot the pump leakage curve with the pump operating time on the horizontal axis and the leakage rate and volumetric efficiency on the vertical axis; if the leakage rate exceeds 50% of the normal value, the pump must be taken out of service for repair. 3. Check the current value. Large hydraulic stations in the metallurgical industry are hydraulic systems composed of multiple piston pumps, along with large accumulator sets. If one of the pumps has high internal leakage or is unable to reach the required operating pressure, the impact on the pressure and flow rate of the entire hydraulic system may not be apparent immediately. Therefore, maintenance personnel must check the current value on the ammeter of the operating pumps on a daily basis and keep records. If the operating pressure of one pump in a pump group is lower than that of the other pumps, the pump with the lower pressure will show a lower current value on the ammeter compared to the pump that is operating normally; in other words, the pump that does less work requires less current than the pump that performs normal work. 4. Measure the pump casing temperature. Hydraulic piston pumps suffer from high internal leakage; an increased clearance between the friction pairs inside the pump leads to the leakage of pressure oil. The leaked pressure oil is converted into heat energy, which inevitably results in a temperature difference between the pump casing and that of a normal pump. If the bearings inside the pump suffer from fatigue wear, the bearings heat up and produce noise; heat will then be detected on the outer surface of the pump casing. These two types of heating can be detected using an infrared thermometer for comparison – the surface temperature of a pump casing with problems will be higher than that of a hydraulic pump casing operating normally. The inspection personnel should use an \"electronic thermometer\" to measure the temperature at three locations – the outside of the pump shaft, the middle part of the pump casing, and the back cover of the pump – every 4 hours. They should record these temperatures on a temperature rise curve chart. This chart can be provided to the technicians along with the pump monitoring data, thereby aiding them in making accurate judgments about the pump. Learn more: Nippon Sharyo piston pumps