【Haichuan Illustrated Chemical Equipment】Series Posts -- Water ring vacuum pump: How to create a vacuum using water

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This post was last edited by HaiChuanLaoYu on 2026-5-7 21:29. Getting to know equipment, understanding it, and making good use of it – the [HaiChuan’s Guide to Chemical Equipment] series of posts: https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=5719196. Everyone is welcome to participate in the discussions. ----------------------------------------------------------- Water ring vacuum pump: How to create a vacuum using water. A pump that doesn’t require pistons or screws; it relies solely on an eccentrically positioned impeller and a ring of water to create a vacuum inside a container. Metal-to-metal friction without precise clearance, no lubricant contamination; water serves both as a sealing medium and as a cooling fluid. The entire pump has no valves, yet it achieves a complete suction-compression-exhaust cycle. A liquid ring vacuum pump is a positive displacement vacuum pump that uses a liquid (usually water) as the working medium. Compared to vane pumps and screw pumps, its greatest advantage is that it can directly draw in gases containing water vapor, condensable gases, and even gases with a small amount of dust, and its exhaust temperature is extremely low (close to the water temperature), making it particularly suitable for pumping flammable and explosive gases. Using 5 sectional views of engineering blueprints, this article takes you through every detail of the Qingshui ring vacuum pump, from a macro perspective to a micro one. The core structure of a water ring vacuum pump is extremely simple: a cylindrical pump casing, within which an multi-blade impeller is mounted eccentrically. The axis of the impeller does not coincide with the center of the pump casing – the eccentricity is usually 5% to 15% of the pump casing radius. The pump casing is pre-filled with about 30% of its volume with working fluid (water). As the impeller rotates, the water is flung toward the casing walls by centrifugal force, forming a water ring of approximately uniform thickness. Due to the eccentricity of the impeller, the space between the impeller blades and the water ring (the air chamber) changes periodically during rotation: one side of the air chamber expands (intake), while the other side compresses (exhaust). The end caps at both ends of the pump casing are equipped with crescent-shaped intake and exhaust ports, which are precisely aligned with the corresponding expansion and compression zones. Typical specifications: impeller diameter 250~1200 mm, speed 730~1450 rpm, ultimate vacuum level -0.097 MPa (approximately 33 mbar gauge pressure).