Introduce the advantages and disadvantages of the ways in which the pump affects the water pump introduced below. The disadvantage is that changing the pump speed requires variable frequency technology to change the speed of the prime mover (usually an electric motor), which is complex in principle, requires a large investment, and has a small flow adjustment range.

operational principle

By relying on the rotation of the impeller to obtain centrifugal force, the material is extracted when the gas density reaches the working range of the mechanical vacuum pump, gradually obtaining a high vacuum.

Fill the pump body with an appropriate amount of water as the working fluid. When the impeller rotates in a clockwise direction, water is thrown around by the impeller. Due to the centrifugal force, the water forms a closed ring of approximately equal thickness, which is determined by the shape of the pump chamber. The inner surface of the lower part of the water ring is exactly tangent to the impeller hub, and the upper inner surface of the water ring is in contact with the top of the blade (in fact, the blade has a certain insertion depth inside the water ring). At this point, a crescent shaped space is formed between the impeller hub and the water ring, and this space is divided into several small cavities equal to the number of blades by the impeller.

If the lower part of the impeller is taken as the starting point at 0 °, the volume of the small chamber of the impeller increases from small to large before 180 ° rotation, and it is connected to the suction port on the end face. At this time, gas is sucked in, and when the suction is completed, the small chamber is isolated from the suction port; When the impeller continues to rotate, the small cavity changes from large to small, causing the gas to be compressed; When the small chamber is connected to the exhaust port, gas is expelled from the pump.