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Brief Discussion On Pump Fault And Overhaul
- Feb 07, 2018 -

Water pump as a source of water transmission and booster device in the water supply system plays an important role. It is widely used in water supply and drainage of Liaohe oilfield water supply company. In view of the present situation of water supply and sewerage system, this paper mainly analyzes the common running faults and the causes of the centrifugal pump in the course of its use, and puts forward the general method of fault treatment, which will be helpful to improve the safety, reliability and efficiency of the pump equipment and ensure the efficient use of the water supply equipment.

In order to ensure that the unit is in good technical condition, better for the people's Living water to provide services, all the mechanical and electrical equipment in the pumping station, must carry out normal inspection, maintenance and repair, update those difficult to repair vulnerable parts, repair those can repair parts. Through maintenance and repair can detect problems in time, eliminate hidden dangers, prevent accidents, ensure the reliability and stability of unit operation, improve the equipment's intact rate and utilization, prolong its service life.

Through the maintenance and overhaul of the unit, we can find the problems of design and manufacture, accumulate experience, and provide the basis for the design of pumping station, the improvement of management level of pumping station and the renovation of pumping station.

The maintenance of Unit 1 is not only the key of management, but also the basis of safe operation. Therefore, the following requirements for maintenance work

(1) Establish a sound overhaul organization to ensure the smooth maintenance work. All mechanical and electrical equipment must undergo the examination of technical personnel and technical workers for maintenance, strictly prohibited operation.

(2) According to the equipment maintenance, maintenance system or regulations stipulated in the period of maintenance, strict implementation of standards, so that the host and auxiliary equipment in a good technical state.

(3) The preparation of detailed overhaul plan, the preparation before overhaul, earnestly fill in the overhaul records, comprehensive collection of maintenance items consumed materials, spare parts, funds and so on, in order to gradually implement the accumulation of quota management data.

(4) Adhere to the high standards of completion of maintenance tasks, and actively carry out technical, economic contracting responsibility system, strengthening the maintenance of technical inspection and accounting.

The common fault of the pump is divided into two kinds: mechanical fault and hydraulic fault. The major failures that occur during use and their possible causes are as follows:

(1) pump does not water. The main causes of this failure are: The pump is not filled with liquid, the suction water height is too large, suction pipe has air or gas leakage, the liquid temperature is too high;

(2) Water pump vibration. The main causes of this failure are: the center of the pump and the original motive is not within the standard; the ground angle screws of the pump body are loose, or the foundation is not firm; the bearing cover is not tight enough to cause the bush to beat in the body; the rotor is unbalanced, the natural frequency of the rotor is proportional to the excitation frequency, and the small flow rate and the flow rate are unstable. Or the middle recirculation door is damaged.

(3) Insufficient flow. The main causes of this failure are: suction valve or impeller is blocked, the suction height is too large, into the pipe elbow too much resistance, pump body or suction tube leakage, filling place leakage, seal ring wear too much, impeller corrosion, wear and tear.

(4) Insufficient output pressure: The main cause of this failure is: the medium has gas, impeller corrosion or serious damage.

(5) Excessive power consumption: the main causes of this failure are: the packing gland is too tight, filling letter fever, the coupling leather ring too tight, rotating part of the axle curtain too large, center line offset;

(6) The bearing is overheating. The main causes of this failure are: Center line offset, oil or oil is not clean, oil ring rotation is not flexible, bearing damage.

(7) Leakage of seal is too large. The main causes of this failure are: filler or sealing element material selection is not correct, shaft or sleeve wear, shaft bending, centerline offset, rotor imbalance, vibration too large, dynamic and static ring corrosion deformation, seal surface is scratched, spring failure or pressure is insufficient, cooling water is insufficient or blocked.

2 failure should be eliminated in time, can not make the machine "sick" work. Troubleshooting should follow the following guidelines

Clarify performance-analyze causes-to be eliminated. Before the pump overhaul, the pump must be thoroughly and carefully inspected in order to determine the maintenance project, the bolt overhaul plan, the main inspection contents are as follows:

(1) measuring the vibration of each part, bearing temperature. Check the bearing for no noise and judge the cause.

(2) The pump shell of the combination of surface and Glen is leaking. Check the running log to find out the current, pressure, operation and defects under full load and record.

(3) Check the bearing ball and inner and outer ring, if found to have cracks, pitting, skin, hemp points and other defects should be replaced.

(4) Check the outer surface of the sleeve grinding to the original thickness of 1/3 or have a clear trench mark should be replaced.

(5) The tie gap between the sleeve and the shaft is 0.018-0.08mm.

(6) Check the bending of the measuring axis, should not exceed 0.1mm, the ellipse and taper of the axes should be not less than 0.03mm, and surface without burr, hemp point, Groove Marks, the thread on the shaft should be perfect, no slip-buckle phenomenon.

(7) Check, measuring shaft and bearing with the interference amount, should be less than 0.01mm.

(8) Check the coupling, shaft and key coordination, coupling and key on both sides should be no clearance, the top should be left with 0.35mm-0.6mm clearance, coupling and shaft with the coordination of K8/H7 level.

(9) Bearing outer ring and shell for K8/h7 level.

(10) Check the packing box inside the surface has no wear, groove (especially axial groove), packing the interface position should be staggered 90-180°, tightness appropriate, and have a tight margin.

(11) Check the impeller outside diameter to shake not more than 0.3mm.

3 Maintenance Safety Construction technical measures

(1) Before overhaul the main pump switch must power off, hanging "someone work, no electricity" warning signs.

(2) Before the commencement of inspection tools are complete, good.

(3) Contact pump workers to confirm that the pump has been powered off, pressure relief. Hang the stop start warning sign.

(4) Closing the inlet and outlet valves, isolating the source of the liquid and ensuring the valve is free of leakage.

(5) Open the discharge valve, eliminate the residual pressure in the pump shell, and put the residual liquid in the pump shell.

(6) Remove the screw and the outlet section of the water side bearing gland, the connection nut between the three parts of the packing and the bearing body, remove the bearing body.

(7) Remove the nut on the shaft, then remove the bearing inner ring, bearing gland and baffle, then remove the packing.

4 Water pump overhaul must pay special attention to matters

(1) The axial channeling clearance of the rotor;

(2) The shaking value of the rotor;

(3) sleeve leakproof rubber ring;

(4) tight-through-bar bolts;

(5) The rotor do not casually disk movement;

(6) Adjust the concentricity of the rotor and stator;

(7) The center of the school to consider the amount of thermal expansion.

The fault of the pump in the course of using is different with the use environment, its maintenance and overhaul methods are also different, should be based on actual production requirements and specific conditions to implement, but also pay attention to the daily use of data collection and accumulation in order to take timely measures to ensure the normal operation of the pump.