Gear pump vibration elimination method

In rotating equipment and flowing media, low-intensity mechanical vibrations are unavoidable. Therefore, in the process of manufacture and installation of the unit, the interference caused by vibration should be avoided as far as possible in the design, operation and management of the unit, and the vibration hazard should be minimized. When the gear pump room or unit vibrates, it is necessary to analyze the causes of the vibrations one by one according to the specific situation. After finding the crux of the problem, take effective technical measures to eliminate it. Some measures are relatively simple and some are quite complicated. If a large amount of capital is needed, a technical and economic comparison of the several options that can be used should be made, combined with the technological transformation of the unit. The following are common causes and elimination measures for motor, pump and pump room vibration.

Common causes of motor vibration and elimination measures:

1. Partial wear of bearings: Units do not wear out with different hearts or bearings. Elimination measures: Re-align the unit concentricity and adjust or replace the bearings.

2. Stator rotor friction: uneven air gap or bearing wear. Elimination measures: Re-adjust air gap, adjust or replace bearings.

3. The rotor cannot stop at any position or the power is unbalanced. Elimination measures: Recalibrate rotor static balance and dynamic balance.

4. Axial looseness: Loose or poorly mounted screws. Elimination measures: Tighten the screws and check the installation quality.

5. The foundation is in vibration: The basic rigidity is poor or the bottom corner screw is loose. Elimination measures: Reinforce the foundation or tighten the corner screws.

6. Three-phase current instability: Torque decreases, rotor cage bars or end rings fail. Elimination measures: Check and repair rotor bar or end ring.

Common causes of gear pump vibration and elimination measures:

1. Difficulties in manual cranking: Bending of the pump shaft, wear of the bearing, misalignment of the unit, and collision of the impeller with the pump casing. Elimination measures: Straighten the pump shaft, adjust or replace the bearing, recalibrate the unit concentricity, and adjust the clearance.

2. The gear pump shaft is excessively pendulum: The bearing and journal are worn or the clearance is too large. Elimination measures: Repair the journal, adjust or replace the bearing.

3. Hydraulic imbalance: Imbalance of the impeller, clogging or damage of the individual blade slots of the centrifugal pump. Elimination measures: Recalibrate impeller static balance and dynamic balance, eliminate plugging, repair or replace impeller.

4. Axial pump shaft power is too large: the water level in the inlet tank is too low, the depth of the impeller is not enough, the debris is wound around the impeller, the pump cavitation damage is different, and the impeller is defective. Eliminating measures: Raise the water level in the water tank, reduce the installation height of the water pump to eliminate impurities, set the fences, and repair or replace the impeller.

5. The foundation is in vibration: the basic stiffness is poor or the bottom corner screw is loose or resonant. Elimination measures: Reinforce the foundation and tighten the anchor bolts.

6. The efficiency of the centrifugal pump unit drastically decreased or the efficiency of the axial flow pump unit decreased slightly, accompanied by cavitation noise. Elimination measures: Change the pump speed, avoid the resonance area, find out the cause of cavitation, and take measures to eliminate cavitation.

Vibration caused by other reasons and elimination measures:

1. The trash racks are blocked and the water level in the pool is reduced. Elimination measures: Clean the fences and install a new sewage cleaning device.

2. The design of the front pool and the intake pool is irrational, and the inlet flow path and the pump are not matched so that the water inlet condition deteriorates. Eliminating measures: The cleanliness of the fences shall be cleaned, and the design of the sewage cleaning device shall be rationally designed and the design of the front pool, the inlet pool and the inlet flow path shall be added.

3. The siphoning time is too long to allow the unit to operate in non-design conditions for a long time. Eliminating measures: Add vacuum device and rationally design and improve the siphon discharge channel.

4. The inlet pipe is not fixed or causes resonance. Eliminating measures: Adding pipe piers and support piers to reinforce pipeline support, change operating parameters, and change operating parameters to avoid resonance.

5. Tap the door repeatedly hit the door or close the impact force is too large. Elimination measures: A vent hole is provided in front of the outlet of the flow channel (or pipeline), and a reasonable design is adopted to take control measures to reduce the impact force when the flap is closed.

6. Rapid pressure changes in the outlet pipe and water hammer. Elimination measures: slow-closing valves, pressure regulating wells and other water hammer prevention measures.

7. The order of startup and shutdown of the unit is unreasonable, resulting in deterioration of the water inlet condition of the pump. Elimination measures: Optimize the start and stop sequence.