Seeking help with vibration issues in the boiler feed water pump
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Urgent help needed: The boiler feed pump in my company is manufactured by Chongqing Pump Factory, with the model number ZDG250-135*12； The rated flow rate is 250 cubic meters ； The rated pressure is 16.5 MPa, with a speed of 3000 revolutions per minute. Recently, during operation of this pump, the vibrations at the drive end were measured at 2.7 mm/s vertically and 10.3 mm/s horizontally; the vibration amplitudes were 0.008 vertically and 0.095 horizontally ； The vibration speed at the non-driven end is 0.9 mm/s vertically and 10.1 mm/s horizontally; the vertical amplitude is 0.009 mm, while the horizontal amplitude is 0.094 mm ； The alignment data for the coupling show a radial error of around 0.06 mm upward and downward, with an error of 0.03 mm; the axial error is also around 0.06 mm upward and downward in the radial direction, with an error of 0.02 mm. Please, experts, help analyze this.
How is the leakage check for the equipment?
After installing the bearing end cover, the rotor stack height is 0.25 mm, which is within the allowable range.
It's possible to find the alignment data; it is recommended to perform dynamic balancing on the shaft.
What should the standard for each value be?
This feed water pump has been in operation for over 8,500 hours; the standard total runout of the rotor is 6–8 mm, and the clearance at the tail cover is 0.25–0.35 mm
The horizontal vibration is higher than the vertical one; rigidness issues are ruled out, the coupling alignment is fine – could it be a problem with the impeller? Dynamic balancing issue? Bearing problem? It is necessary to examine the frequency components and conduct on-site inspections for a detailed analysis.
Could it be that prolonged operation has caused an increase in the gap around the mouth ring, leading to higher inter-stage losses; or perhaps the excessive temperature in the outlet section is responsible for vaporization? Please disassemble and inspect the balance disc and sealing shaft sleeves in the non-driving section to check for any signs of erosion. .
The bearing wear, as checked, is also within acceptable limits; it can still operate normally at the moment, but it’s not clear whether continuing to operate in this condition is feasible