300M head of 11 stage centrifugal pump with 22KW motor, empty (not water) current of 13A, the water into the pump, current up to 44A, open the outlet valve of the current rising to 100A, immediately shut the gate current is up to 170A, the motor stop. Without any problems, not on the impeller pump shaft is not clean the shell the balance sheet, no wear, bearing normal.
The description of the problem is very clear. Most of this kind of circumstance is overload, is also the outlet pressure is very low, the flow is greater than the rated value caused by the resistance can be adjusted by increasing exports or close the outlet valve, reducing the flow resistance increased by less than or equal to the rated flow. Lift is not an influencing factor.
(1) the influence of the basic installation on the equipment.The quality of equipment foundation installation has great influence on the quality of equipment operation. Iron pad placed properly, causing around the foot bolt hanging device, in alignment and fastening process for iron pad hanging, tighten anchor bolts will cause deformation of crosshead slide in the crankcase, the cross head is blocked in the operation of reciprocating load increases when the chute.W5 type reciprocating vacuum pump in the structural design of the cylinder body is cylinder, and the piston, intake and exhaust valve after the heavy weight in the foundation design without considering the cylinder support or hanger, the cylinder will be in a suspended state, because the weight of the crankcase cylinder will cause deformation of the cylinder and slide and slide the concentric degree of difference, so that the cross head is blocked in the slideway and the piston reciprocating operation is blocked during the reciprocating motion in the cylinder caused by the increase of the load.According to the above analysis, inspection found that the vacuum pump end of the cylinder body is slightly lower than the end of the crankcase, cylinder pad iron is low, deformation of crosshead guide foot bolts, the cross head caused by load increases in the slideway and the piston in the cylinder reciprocating operation is blocked, this is one of the reasons causing motor overheating.(2) cylinder and valve coking;The influence of process, cylinder and valve of reciprocating pump is easy to coke, Coke will cause the piston cylinder and piston in reciprocating cylinder operation when the load increases the valve is blocked; coking will cause poor exhaust, the valve closed lax, increasing load, low vacuum degree; clearance at the cylinder piston striking the cylinder will cause coke it will increase the load of cylinder, valve has found the phenomenon of coking, which is mainly caused by the low degree of vacuum.
Main reasons: 1. bearing lubrication is not good or bearing quality problems appear peeling phenomenon, resulting in increased resistance to pump operation.2., the pump cover and impeller clearance is too small, the impeller mouth and pump cover friction.3 belt tight, resulting in heavier load.4. centrifugal pump power is proportional to the flow, the greater the flow, the greater the power needs, large, low head flow, resulting in heavy load.Water pump maintenance: 1., water pump to do routine maintenance, check the water seal every day, to prevent water damage, water directly into the bearings, accelerated wear and tear.2. belt adjustment should be appropriate, not too loose, too tight.3. strictly according to the standard operation, for the low lift pumping load, it is necessary to control the flow by throttling, thereby reducing the load.
