Intermittent failures of water ring vacuum pumps in winter
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In the atmospheric and vacuum distillation unit, a three-stage vacuum extraction system is used – with stage 1 not being active and stage 2 utilizing steam ejectors. Since August, a set of water ring vacuum pumps has been in use, operating steadily; in fact, there is no need to replace the working fluid over long periods of time； Since the end of December and into January, there have been frequent instances of increased pump noise, which has led to a decrease in the vacuum level at the top of the tower. At the same time, the secondary extractor also produces a \"surging\" sound; adjusting the reflux control valve does not have much effect. The temperature of the working fluid desalinated water is 20°C (cooled by heat exchange with circulating water), and the liquid level is 50% ± 5. The temperature at the top of the vacuum tower is 15–18°C, the vacuum level is maintained at -97–98 KPa, and the inlet pressure of the liquid ring pump is generally kept at -88–90 KPa. It’s mainly the effect of low temperatures. Work fluid contamination has been ruled out, and the liquid level in the double-flange separator tank is normal. Each time we handle this issue, we stop the pump; after a few seconds, by turning the shaft manually the pump starts up again and functions normally. It can operate for 2 days before problems arise again, at which point we restart it.
From a narrative perspective, it’s a strange question. A water ring pump is actually quite simple: as long as the liquid level is maintained, the rotation speed remains constant, and the blades are not damaged, the vacuum-pumping capacity will be ensured. Regarding this, \"every time we deal with this issue, we stop the pump; after a few seconds, we restart it by turning the shaft, and it works fine for 2 days before the problem occurs again, at which point we restart it once more.\" ”During this pump shutdown of a few seconds, what happened? It is recommended to first check the inlet and outlet pipelines of the pump to ensure they are unobstructed
Compared to summer, the pressure in the liquid separation tank (i.e., the gas external network) drops from about 6 KPa to 0.5 KPa; will this affect water supply?
It is recommended to check the rotor and the crescent plate check valve.
1. Check whether there is liquid accumulation in the return pipeline and suction pipeline； 2. Check whether the working fluid is too large or too small, and whether it is within the appropriate range. 3. Check if the rotor blades are excessively worn
Check whether the circulating water used for heat exchange of the working fluid is functioning properly. The next time the pump is stopped, the temperature of the working fluid can be measured; it’s possible that the working fluid has vaporized, resulting in cavitation. At this vacuum level, the operating temperature of the working fluid should be below 40 degrees Celsius, which should be sufficient. Also: Has there been any change in the inlet pressure of the pump?
It is recommended to check whether there are any issues with the valve plates inside the pump.