Closed Coupled Liquid Ring Vacuum Pump Liquid Ring Vacuum Pump is a vaccum producing pump. Water is used by the pump to create vaccum and strong suction capability. Liquid Ring Vacuum Pump is widely used in the food and beverage industries such as beer industries. The liquid ring vacuum pump is used to suct gas and bubbles out of the bottle during packaging. Liquid Ring Vacuum Pump is also widely used in Pharmaceutical and food processing and plastic extruder industries.