Concerns: the use of water ring vacuum pump and precautions

Water ring vacuum pump, in general, the working fluid used is water. The energy acting on the rotor impeller is received by the liquid and transferred to the compressed gas, thus causing the temperature of the water ring to rise. A portion of the water in the ring is compressed with the gas to exclude the pump. Most of the heat generated during the compression is taken away. Therefore, it is necessary to constantly replenish the fresh water so that the working temperature of the water ring pump can be kept constant. In most water ring vacuum pumps, the operating temperature is about 15-20 ° C, depending on the temperature of the water being replenished. Humidity sensor probe, stainless steel heating tube PT100 sensor, cast aluminum heater, heating coil fluid solenoid valve In fact, the ultimate pressure of water ring pump is not very important because of different liquids at pressures below 50-60hPa, Cavitation occurs and pump parts can be damaged. When the pump approaches the limit pressure, the pumping speed is very low and the water at the pump inlet starts to boil. As you go to the outlet of the pump, the bubbles that form begin to crack. This will produce a lot of noise, while the pump drive wheel and pump chamber and other components are gradually destroyed. This phenomenon is commonly referred to as cavitation. Once cavitation occurs, introduce a small amount of fresh air through the valve. In this case, a hole was made in the entrance gate to allow for some fresh addition to the volume, and cavitation did not occur if a gas jet was used. Single-stage water ring pump is only suitable for the inlet pressure of 130-1013kPa pressure range, the compression ratio of 1: 7. If the inlet pressure is lower than 130kPa, it is recommended to use two-stage water ring pump. In the two-stage pump, the two pump chambers are connected in series and the working chamber volume ratio is about 2.5: 1. The ultimate pressure of a two-stage water ring pump depends on the water's vapor pressure. Assuming that the water vapor pressure at the pump operating temperature is pH2O, the inlet pressure is pA, and the geometric pumping speed is Sth, it is empirically known that at pump pressures below 130 hPa, the effective pumping speed of the pump is SA = Sth (1-pH2O / pA ) Taking into account the lower vapor pressure of the oil, a two-stage liquid ring pump can also be used as a working fluid for the pump, thus achieving a lower ultimate pressure. However, where it is necessary to remove a large amount of water vapor, especially in the case of roughing and oil, the liquid ring pump rarely uses oil as a pump fluid because the oil tends to absorb water to form an emulsion. If oil is used as pump fluid, an oil cooling device is also provided on the pump to dissipate the heat of compression. Rarely use three or more levels of liquid ring pump. However, liquid ring pumps are often used in series with gas injectors, water injectors and Roots pumps.