Greentech International (Zhangqiu) Co., Ltd.
Greentech Industry (Jinan) Co., Ltd.
If you choose a 2BV2 liquid ring vacuum pump because the specification says it can reach 33 mbar, it is natural to expect the same result after installation. But in real operation, you may find that the pump stops at 50, 70, or even 100 mbar. So, is there a problem with the pump? Not necessarily.
The key point is that rated ultimate vacuum is not the same as actual operating vacuum. The 33 mbar value is normally measured under specific test conditions, such as an inlet gas temperature of about 20°C, working liquid temperature of about 15°C, and discharge pressure of around 1013 mbar. In a real system, water temperature, gas load, pipe layout, leakage, exhaust pressure, pump speed, and even the vacuum gauge can affect 2BV2 vacuum performance.
Ultimate vacuum means the lowest absolute pressure a vacuum pump can reach when the system is properly sealed and the operating conditions are suitable. For a 2BV2 liquid ring vacuum pump, 33 mbar is an important performance reference. However, it should not be understood as a pressure that every application can continuously achieve.
In a real factory, the pump is connected to process equipment, valves, pipelines, seals, filters, and other components. If one part of the system has a problem, the final vacuum level may be much higher than the pump's rated value.
Think of it this way: the pump itself may be able to reach 33 mbar, but the complete vacuum system may not. This is why checking only the pump is not enough. You need to check the entire system.
Working liquid temperature is one of the first things to check when a 2BV2 cannot reach a deep vacuum. The working liquid forms a liquid ring inside the pump to seal and compress the gas. When the liquid becomes hotter, its vapor pressure increases. This makes it harder for the pump to reach a low absolute pressure.
This problem can become more obvious in summer. A pump may perform well with cool working liquid during testing, but the water in a factory can become much hotter after several hours of operation. If the vacuum becomes worse as the pump continues to run, rising working liquid temperature is worth checking first.
Measure the actual working liquid temperature at the pump inlet. If it is too high, improve cooling, increase fresh working liquid supply when suitable, or add an appropriate cooling system.
Working liquid flow is also important. If the flow is too low, the liquid ring may not form correctly. The pump may continue running, but its vacuum performance can become poor.
However, more water is not always better. Excessive working liquid can increase power consumption and may affect stable operation. Always check the recommended flow for your specific 2BV2 model instead of using a random water supply setting.
A small air leak can have a big effect when the system is trying to reach a deep vacuum. Check the suction flange, pipe connections, valves, gaskets, mechanical seals, inspection ports, and flexible connections.
Air leakage can be difficult to hear because the system is under vacuum. Outside air may simply be pulled into the system through a small gap. If the pump runs normally but the vacuum never gets close to the expected level, system leakage should be one of the first things to check.
The pump does not work alone. Long suction pipes, small pipe diameters, too many elbows, dirty filters, and partially closed valves can increase resistance and reduce effective pumping performance.
Gas load also matters. If the process contains a large amount of air, vapor, or other gases, the required pumping capacity may be much higher than the conditions used during a simple vacuum test.
High exhaust pressure can also affect pump operation. Check whether the outlet line is blocked, undersized, or connected to equipment that creates excessive back pressure. A restricted discharge path can make it harder for the pump to work properly.
The 2BV2 needs to operate at the correct speed for its model and motor configuration. If the actual speed is lower than expected, pumping performance may also decrease.
At the same time, do not forget the vacuum gauge. A gauge that is inaccurate or poorly calibrated can make a properly working pump look like it has a problem. Before replacing pump parts, compare the reading with another reliable pressure instrument.
When your 2BV2 cannot reach the expected vacuum, start by checking the working liquid temperature and confirming the working liquid flow. Then inspect the suction system for air leaks and check the valves, filters, elbows, and pipe size. After that, look at the process gas temperature and gas load, followed by the discharge pressure, pump speed, motor rotation, and vacuum gauge accuracy.
Checking these points step by step can help you find the real cause much faster instead of replacing parts without knowing what went wrong.
When a 2BV2 does not reach 33 mbar, replacing the pump should not be the first step. Start with the working liquid, then check system leakage, piping, gas load, discharge pressure, pump speed, and measurement accuracy.
In many cases, the pump itself is not the real problem. The key idea is simple: 2BV2 ultimate vacuum is a rated performance point, not a guarantee that every complete vacuum system will reach 33 mbar.
Once you understand this difference, troubleshooting becomes much easier. Instead of immediately blaming the pump, you can check the operating conditions and the complete vacuum system first. This can save maintenance time, avoid unnecessary replacement, and help your 2BV2 liquid ring vacuum pump deliver better vacuum performance.
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