Service Model: Maintenance and repair for oil leakage on the German Becker U4.250 vacuum pump.
Repair Process: After troubleshooting and resolving the oil leak, as well as cleaning, reassembling, and testing the Becker Roots vacuum pump (model U4.250), we conduct a 2–8 hour trial run. Once we confirm there are no issues, we notify the customer to arrange payment. Upon receipt of payment, we arrange for the pump to be returned to the customer either via our own staff or through a courier/logistics service. To prevent damage during transit, we pack the repaired pump in a specially constructed wooden crate.
Troubleshooting Common Faults of the Becker U4.250 Vacuum Pump
1. Fault Symptom: Insufficient pumping capacity of the Becker U4.250 vacuum pump
Causes:
(1) The rotational speed of the Becker U4.250 vacuum pump is insufficient;
(2) Poor sealing, resulting in air leakage at the intake pipeline connections or the shaft seal;
(3) Excessive clearances—specifically between rotors, between the rotor outer surface and the pump housing, or between the rotor end face and the end cover—leading to increased gas backflow;
(4) Excessive ambient temperature or cooling water temperature.
2. Fault Symptom: Insufficient vacuum level in the U4.250 pump
Causes:
(1) Poor sealing in the intake system, resulting in air leakage;
(2) Poor sealing of the U4.250 pump itself, with air leakage at the shaft seal;
(3) Excessive clearance between rotors or between the rotor and the housing, or excessively high air temperature;
(4) Excessive pressure difference between the inlet and outlet gas media of the U4.250 pump.
3. Fault Symptom: Difficulty restarting the U4.250 pump after shutdown
Causes:
Sometimes, the U4.250 pump operates continuously without any apparent abnormalities; however, if it is stopped for even a short period, restarting becomes difficult or even impossible. This phenomenon may be caused by the following:
(1) Excessive scale buildup on the inner wall of the pump casing and the outer surface of the rotor has blocked the clearance gap;
(2) Failure to thoroughly clean the intake piping during installation or replacement, allowing welding slag or other hard debris to enter the pump;
(3) Rotor axial displacement (shifting), causing friction between the rotor end and the end cover, thereby increasing resistance;
(4) Rotor shaft bending, or seizure of the rotor or synchronous gears.
4. Fault Symptom: Increased noise during operation of the U4.250 pump
Causes:
(1) Friction occurs due to uneven or improper clearances between the rotors, or between the rotors and the casing; in such cases, noise levels can increase sharply;
(2) Poor meshing of the timing gears, excessive backlash (clearance between teeth), or a lack of lubricating oil in the gearbox—resulting in dry friction between the gear teeth—will cause a significant increase in noise within the gearbox;
(3) Excessive rotational speed of the U4.250 pump causes violent collisions of the working media (air and water) within the pump chamber and the stabilizing tank, and may even induce pump vibration, inevitably leading to increased noise.
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