工作轮旋转且达到一定转速时，由于离心力的作用，将液体甩向四周，形成一个贴在缸体内表面的液环。上部液环的内表面与工作轮的轮轂相切，工作轮与液环之间形成一个月牙形空间,此空间被工作轮叶片分成若干容积不等的小室(基元容积)。工作轮旋转时，右半圈的基元容积逐渐扩大，左半圈的基元容积逐渐缩小。相应地在年体两侧端盖上开设镰刀形的吸气口、排气口，右边的大镰刀孔为吸入口，左边的小镰刀孔为排出口。这样，工作轮旋转一周，每个基元容积扩大、缩小一次,并与吸入口、排出口各连通一次 ，实现吸气 、压缩、排气及可能有的膨胀过程。因此，液环泵实际是一种容积式压缩机。
Difference between 4 suction heads and 3 suction heads of multi suction sewage pump
Liquid ring pump is mainly used for vacuumizing and conveying gas medium, and its working principle is shown in Figure 2-11. The impeller with straight blades is eccentrically arranged in the cylinder body, and a certain amount of liquid is introduced into the cylinder body, usually water.
When the working wheel rotates and reaches a certain speed, due to the centrifugal force, the liquid is thrown around to form a liquid ring on the surface of the cylinder body. The inner surface of the upper liquid ring is tangent to the wheel hub of the working wheel, and a crescent shaped space is formed between the working wheel and the liquid ring, which is divided into several chambers (elementary volume) with different volumes by the blades of the working wheel. When the working wheel rotates, the volume of the right half circle increases gradually, while the volume of the left half circle decreases gradually. Correspondingly, a sickle shaped air inlet and an air outlet are arranged on the end covers on both sides of the new year body, the big sickle hole on the right is the air inlet, and the small sickle hole on the left is the air outlet. In this way, when the working wheel rotates for one circle, the volume of each element expands and shrinks once, and is connected with the suction and discharge ports once, so as to realize the process of suction, compression, exhaust and possible expansion. Therefore, the liquid ring pump is actually a positive displacement compressor.
With the discharge of gas, but also entrained part of the liquid discharge, so it is necessary to add a certain amount of liquid in the suction, so that the liquid environment to maintain a constant volume, and to take away heat, play a cooling role.
When the liquid ring pump works, the blade stirs the liquid and produces a great energy loss, which is called hydraulic loss. The energy loss is almost equal to the work consumed by the compressed gas. Therefore, the efficiency of liquid ring vacuum pump is very low, the isothermal efficiency is only 0.30 ~ 0.45, and the large machine can reach 0.48 ~ 0.52.
Liquid ring pump usually uses water as sealing fluid, mostly used as vacuum pump, so it is traditionally called water ring vacuum pump. Due to the full cooling effect of the liquid, the compression process is close to isothermal compression, the final compression temperature of the gas is very low, there is no mutual friction between metal surfaces in the pump, and the medium does not directly contact with the cylinder, so it is suitable for transporting flammable, explosive, high-temperature, easily decomposed and strongly corrosive gases. The machine has simple structure, no need of suction valve and exhaust valve, stable and reliable operation, and even air volume. The disadvantage is that the efficiency is too low.