In the early stages of industrial development, the usual after-repair method of dismantling or replacing parts after the equipment was damaged is actually a completely unplanned emergency with a forced shutdown. Many accidents, at the same time need to pay a lot of maintenance costs and suffered huge losses caused by the production standstill, and was later replaced by preventive maintenance methods before damage.Preventive maintenance is essentially a time-based maintenance system , Which is characterized by the annual, quarter, month, week cycle, the implementation of large, medium and minor repair and inspection system.Because to avoid the maintenance interval is set too long, so that the equipment is not scheduled to repair the damaged time , So the specified time interval, the general than all parts of the machine rated life short, no doubt this will increase the number of routine maintenance.Preventive maintenance methods to a certain extent, to ensure the normal operation of the machine.But it regardless of the maintenance of the machine Parts of the actual degree of wear and tear, as long as the reservation period of use, must be forced to replace or repair, which not only artificially increased machine down times Number and time, resulting in reduced production and less machine maintenance costs, but also due to frequent disassembly and reduce the actual working life of the machine.Active maintenance by the United States Oklahoma State University FitCh Dr. created, is the newly developed one A state-based machine maintenance strategy, which is a maintenance activity taken before a machine starts to fail, by keeping track of the root causes of the system that can cause the failure and correcting the root cause of abnormal conditions in time to keep the machine healthy Work status: Both predictive and proactive maintenance are based on system condition monitoring, but the objects they test are different, and predictive maintenance is the detection of early failure symptoms that reflect material wear and performance degradation, such as wear in the fluid Characteristics and content Vibration and noise, temperature, etc. According to the failure symptoms detected can determine the failure level and fault location, although the predictive maintenance can not accurately predict the exact time of the failure, but maintenance personnel may be warned in advance to take maintenance measures to avoid In the event of a serious shutdown, it is clear that there is only wear and tear on the material due to failure symptoms Performance degradation can be detected, so predictive maintenance can not extend the life of the extension pieces and reduce the frequency of failure, but only to reduce the severity of the failure.Active maintenance focused on monitoring system may lead to material damage to the root causes of the parameters, such as oil Fluid pollution, physical and chemical properties and temperature of the object.Active maintenance is a fundamental change to the maintenance mode, it is not for the failure of the system material and performance maintenance activities, but to prevent such failures from taking place Preventive measures. Its purpose is to maximize the life of equipment and components. The purpose of active maintenance is to maintain the curve before the failure of the horizontal section, and extend as far as possible to extend the service life of equipment. Technology published: Centrifugal pumps, chemical pumps.