Instead of oil, water is used for vacuum sealing, lubrication of rotating parts, and cooling of sliding parts.
The water-sealed pump consists of a circular casing and an impeller, with the impeller mounted in an eccentric position relative to the casing. When an appropriate amount of sealing water is added to the casing and the impeller is rotated, as shown in the diagram, the mass of the sealing water forms a concentric ring along the inner wall of the casing due to centrifugal force. By utilizing the change in volume of the space enclosed by the inner wall of this sealing water ring and the blades of the impeller as the impeller rotates, the actions of suction, compression, and exhaust are continuously performed through the suction and exhaust ports provided on the side wall or the inner wall of the impeller. Furthermore, efficient exhaust is achieved through high-speed rotation. Additionally, the sealing water serves as a seal to ensure that the gas being drawn in is always exhausted.