Pump Fault Diagnosis and Elimination Measures
Abstract
Pumps, as a kind of important equipment, have been widely used in various industries and have been playing a vital role in the operation of industrial production. However, due to the extremely complex structure and working environment of the pump, the pump does not work normally, and sometimes even halts its operation. This paper introduces the common faults and prevention measures of pumps in detail, including the causes of pump failure, the diagnostic methods of pump failure, and the elimination measures of the detected faults. Not only help the user to understand the safety operation, maintenance and repair of the pump, it can also provide certain reference for the correct selection, application and operation of the pump for the user.
Keywords: pump; fault; diagnose; elimination; measure
1 Introduction
With the development of science and technology, pumps have become an indispensable equipment in all kinds of industrial production. It has the functions of conveying, pressing, draining and so on. Due to the long-term operation, harsh working environment and unreasonable maintenance, the pump often fails to work, resulting in the normal production of the enterprise, pollution and other environmental losses. Therefore, it is very important to diagnose the fault and timely eliminate the fault.
2 Common pump faults and prevention measures
2.1 Main rotor leakage
The main rotor leakage of pump refers to the leakage of the packing or mechanical seal at the joint of the stationary and rotating parts of the pump. There are many reasons for its leakage, including overheating, misalignment, mechanical damage, system blocking, poor lubrication, poor manufacturing quality, overpressure, shaft wear and so on.
The preventive measures for rotor leakage in advance mainly include: first, to adjust the sealing device of the pump in time and do a good job of inspection and maintenance when starting the pump; second, to keep the inlet pressure, temperature and rotational speed constant, so as to reduce the interference of external factors; third, to maintain proper lubrication condition of the bearing during operation of pump, also, to ensure normal rotational speed, water temperature, etc., to make sure its reliability.
2.2 Cavitation
Cavitation occurs when the pump vacuums or absorbs the liquid substance abnormally, causing the pressure at the inlet of the pump to reduce, forming bubbles, and the bubbles burst violently in the pump when they are forced to the outlet of the pump, resulting in a great noise. The main causes of cavitation are excessive negative pressure, excessive suction, sudden change of flow rate, or too low suction.
The preventive measures mainly include: first, to raise the inlet pressure of the pump; second, to increase the capacity of the pump; third, to reduce the suction height; fourth, to strengthen the regular inspection, timely replacement of the filter core, and to prevent cavitation.
2.3 Axial vibration
The causes of axial vibration of pump are mainly caused by the frame, rotor, misalignment of parts and soft foundation. The preventive measures mainly include: first, to adjust and adjust the motor, bearing and other equipment of the pump and to correctly install the pump; second, to determine the axial thrust between the end face of the impeller and the volute, and to adjust it in time to ensure that the axial force is moderate; third, to ensure the tightness of the bolts and the removable parts.
2.4 Radial vibration
Radial vibration is often caused by unbalance caused by the distorted blade or fretting of the impeller blades and so on. The preventive measures mainly include: first, to monitor the axial thrust of the impeller, and to replace the distorted or abraded blades in time; second, to maintain the balance weight correctly and make sure the pump runs in balance; third, to keep the pump cavity and the outlet end face clean, so as to reduce the turbulence and vibration caused by contact friction.
3 Diagnosis and elimination measures of pump faults
3.1 Fault diagnosis
The failure of the pump will affect the safe operation of the unit and the production efficiency of the plant. Before the repair and maintenance of the pump, the fault must be accurately diagnosed and targeted measures taken for the corresponding fault. Specific matters are as follows:
1) Listen to the noise of pumps. After the start of operation, make a comprehensive judgment with the sound of pumps. If there is a loud noise, it may be caused by unbalance of the rotor, looseness of the bolt, rotor hitting the casing and so on.
2) Observe the vibration. Generally speaking, the vibration of the pump should be very light, and the balance should reach G2.5 (the vibration standard). If the vibration is large, it is necessary to check the cause.
3) Check regularly. It is necessary to check the noise, vibration and surface temperature of the pump regularly, and record After the start of operation, the sound and vibration of the pump will change from large to small. If this change is not obvious, it may indicate a fault of the pump.
3.2 Fault Elimination
According to the fault points and causes, targeted treatment should be carried out, and the following measures should be taken:
1) The symmetrical distance between the pump suction and delivery sides hits the center line of the rotating parts and the coupling of the main engine. If there is misalignment, reset it or adjust it in time.
2) Balance check. Test the unbalance of the rotor, replace the blade or balance weight in time if the unbalance exceeds the standard.
3) Lubrication check. Check the wear condition of the bearing and the oil level and quality of the lubricant in time, and determine the lubrication pressure and speed of the bearing according to the pump model.
4) Check the pipeline and pipeline components for blockage. If the pipe parts are too thick or too long, the calorific value will decrease, causing the pump to cavitate or form negative pressure and other conditions.
5) The impeller and inlet area must be kept clean.
4 Conclusions
The pump is an important equipment for industrial production. Due to its complex structure, various faults are easily occur during its operation, which affects the normal production of the enterprise. Therefore, understanding the common faults of pumps, diagnosing their faults in time, and timely eliminating their faults are very important in order to ensure the normal production and the safety of the personnel and equipment.
