Performance Evaluation of Vacuum Pumps - Problems and Trouble Shooting

Various factors influence the performance of vacuum pumps. Proper inspection must be done on arrival followed by installation by a qualified technician. It is important to check and ensure that valves are in the correct direction according to the installation manual. Free rotation of impellers and motor must also be checked.

General Operation Problems in Liquid Ring Vacuum Pumps

Liquid ring vacuum pumps can generally develop problems such as stalling while in operation, starting failure and low or poor pumping .These are just a few of the common problems and can be solved through proper maintenance procedures.


In the course of operation, critical problems can arise such as cavitation. This is the development of small crater like holes on the impellers leading to poor performance and reduced life of the machine.

To prevent cavitation from occurring it is important to ensure that the service liquid can maintain the vacuum level without boiling or vaporization of water occurring.

Trouble Shooting Process in Vacuum Pumps

Pharmaceuticals industries usually requires high efficiency, reliability, hygiene, long operation life, less wear and tear, easy operation, lower power consumption and exceptional performances and it is the best to be used in enhancing profit maximization and increasing production.

Importance of Using Vacuum Pump in the Pharmaceutical Industries

System malfunction could be due to operation conditions, equipment failure or both. For operational conditions;

1) Analyze original design parameters and compare with current operating conditions. More emphasis must be on the gaseous composition and temperature of the cooling water. Any deviations may result to performance problems.

2) Check for excessive air leakage. This can be done via the drop test.

3) Confirm back pressure is as per the design conditions.

For equipment failure:

1) Always check the change in temperature of the seal liquid across the system.

2) Confirm equipment speed to be as per design specification.

3) Compare system performance with manufacturer’s performance curve.

Dealing with Problems of High Horse Power

Excessive power can be due to belt misalignment or poor tensioning, water overload, inlet restriction, motor problem or pump over speeding. These are very specific problems and can be managed as they arise. Ensure correct tension of the V belt, unclogging inlets and check for motor problems.

Development of Leakages Leading To Poor Pump Performance

Water leakages occur primarily due to damaged seals. The most common areas where leakage occurs include;

1) Gland packing: tighten or replace the packing

2) Body gasket: tighten the bolts evenly or replace gasket

3) Body plugs: tighten the plugs or check for oxidization and replace.

Vacuuming and Vibration Problems

Vacuum problems could arise due to the in the inlet, seal water flow, changes in water temperature and even fluctuations in the RPM of the motor. Thorough preventive maintenance must be done regularly to avoid these problems. Excessive vibration could be due to flooding of it, misalignment of the belts or couplings, pump mounting, faulty bearings and even excessive wear. These problems must be corrected immediately they arise and ensure proper preventive maintenance.

Persistent Overheating

Persistent overheating could be brought about by high inlet temperatures, high compression quotient, faulty cooling system and clogging of the discharge port which leads to increased back pressure. These can be prevented by regular maintenance and proper monitoring of the operating conditions such as temperatures and the suction. If you want to get more details, fill inquiry form at


Liquid ring equipment have gained popularity over rotary piston and the dry screw pumps. One of the major problems it is cavitation which can lead to serious damage to the pump. While Trouble shooting, it is important to consider operational conditions as well as the equipment internal conditions. Regular preventive maintenance must always be done to the machine to avoid breakdown.

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