Talking about Pump Failure and Maintenance

   Pumps as a source of transport and booster devices play an important role in the water system. Water supply in the Liaohe Oilfield Water Supply Company, a wide range of drainage links. In view of the status quo of water supply and drainage system, this paper analyzes the common operation faults of centrifugal pumps and their causes, and puts forward the general methods of fault handling. It will improve the safety, reliability and installation efficiency of pump equipment, The efficient use of water supply equipment has some guidance and reference.

In order to ensure the unit is in good technical condition and better serve the domestic water supply, all the mechanical and electrical equipment in the pumping station must be inspected, maintained and repaired normally, the refractory parts that are difficult to repair must be renewed, the ones that can be repaired Repaired parts. Through maintenance and repair, problems can be found in time, hidden dangers can be eliminated, accidents can be prevented, the reliability and stability of unit operation can be ensured, and the intact rate and utilization rate of equipment can be increased and the service life can be prolonged.

Through the maintenance and overhaul of the unit, the existing problems in design and manufacture can also be found out, and experience accumulated so as to provide basis for design of pumping station, improvement of management level of pumping station and renovation and reconstruction of pumping station.

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

(1) establish and improve the maintenance organization, to ensure the smooth progress of maintenance work. All mechanical and electrical equipment must be assessed technicians and skilled workers for repair, illegal operations are strictly prohibited.

(2) Carry out overhaul according to the deadline stipulated in the equipment maintenance and maintenance system or the rules and regulations, and strictly implement the standards so that the main engine and auxiliary equipment are in a good technical condition.

(3) Prepare a detailed maintenance plan, make preparations for maintenance, consummate overhaul records, comprehensively collect materials, spare parts, funds and other materials consumed for maintenance projects and accumulate information for the gradual implementation of quota management.

(4) Adhere to the high standards to complete maintenance tasks, and actively carry out technical and economic contract responsibility system, strengthen the technical inspection of inspection and economic accounting.

Pumps common faults are divided into mechanical failure and hydraulic fault two categories. The major faults that occur during use and their possible causes are as follows:

(1) the pump does not water. The main reasons leading to such a failure are: the pump is not filled with liquid; the suction height is too large; the suction pipe has air or air leakage; the liquid being transported is too hot; the suction valve is blocked; the steering error.

(2) pump vibration. The main reasons leading to this failure are: the center of the pump and the prime mover is not within the standard range; the pump body angle screw loosening, or the foundation is not solid; bearing cap is not enough, so that the bearing in the body beating; rotor quality Imbalance; rotor natural frequency and excitation frequency proportional relationship; small flow and flow instability, or the middle of the recycling door damage.

(3) lack of traffic. The main reasons leading to this failure are: suction valve or impeller is clogged; inhalation height is too large; into the pipe elbow too much resistance; pump or suction pipe leaks; packing leaks; seal wear too much Impeller corrosion, wear.

(4) The output pressure is insufficient: The main reason leading to this kind of breakdown is: There is gas in the medium; The impeller is corroded or severely damaged.

(5) power consumption is too large: The main reasons leading to such failures are: packing gland is too tight, stuffing box fever; coupling aprons too tight; rotating part of the axis of the curtain is too large; centerline offset; parts stuck .

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

(7) seal leakage is too large. The main reasons leading to this failure are: filler or seal material selection wrong; shaft or sleeve wear; axis bending; centerline offset; rotor imbalance, vibration is too large; dynamic and static ring corrosion deformation; sealing surface is zoned Injury; lack of spring failure or pressure; lack of cooling water or blockage.

2 with the fault should be promptly excluded, can not make the machine "sick" work. Troubleshooting should follow the following principles

Clarify performance - analyze why - eliminate it. Before the pump overhaul, the pump must be thoroughly and carefully examined to determine the maintenance project, the bolt overhaul plan, the main inspection reads as follows:

(1) Measure the ministries vibration, bearing temperature. Check whether the bearing noise, and determine the cause.

(2) whether the leakage of the pump casing and the Gland. Check the logbook for current, pressure, operating conditions and defects at full load and make a note of it.

(3) Check the ball bearings and the inner and outer rings, if cracks, plaques, peeling, pitting and other defects should be replaced.

(4) Check the outer surface of the sleeve to the original thickness of 1/3 or obvious groove should be replaced.

(5) sleeve and shaft with the gap 0.018-0.08mm.

(6) Check the bending of the measuring shaft should not exceed 0.1mm, the ellipticality and conicity of each journal should be not more than 0.03mm, and the surface without burrs, pits, groove marks, the thread on the shaft should be perfect, no Slip phenomenon.

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

(8) Check the coupling, shaft and key with the coupling and the key should be no gap on both sides, the top should be left 0.35mm-0.6mm gap, coupling and shaft with the K8 / h7 level with.

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

(10) Check the inner surface of the packing box with or without wear, grooves (especially the axial groove), packing the interface position should be staggered 90-180 °, appropriate elastic, and then tight tight balance.

(11) Check the outer diameter of the impeller shaking no more than 0.3mm.

3 maintenance safety construction technical measures

(1) before the main pump switch maintenance must power out, hang "someone working, forbid power" warning signs.

(2) before the start of inspection tools are complete and good.

(3) contact the pump to confirm the pump has been powered off, pressure relief. Hang "no start" warning sign.

(4) Close the inlet and outlet valves, isolated from the liquid source, to ensure that no leakage valve.

(5) Open the tapping valve to eliminate the residual pressure in the pump housing, put the net liquid in the pump casing.

(6) Remove the screws on the water side bearing gland and the connecting nut between the three parts of the packing, packing and bearing body, and remove the bearing body.

(7) Remove the nut on the shaft and remove the packing after removing the bearing inner race, bearing gland and baffle in sequence.

4 pump overhaul needs special attention matters

(1) rotor axial play clearance;

(2) rotor sway value;

(3) sleeve leak-proof rubber ring;

(4) tight through the bolt;

(5) Rotor do not panic;

(6) adjust the rotor and stator concentricity;

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

Pump in use process failure with the use of different environments, the maintenance and repair methods are also different, should be based on actual production requirements and specific conditions to implement, but also pay attention to the routine use of the process of data collection and accumulation in order to appear Problems promptly take measures to ensure the normal operation of the pump.

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