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Water-sealed Liquid Ring Systems

Principle of Operation

As the name implies, water-sealed liquid ring vacuum pumps require water to create a seal inside the pump. The impeller is the only moving part. It rotates without contact within the pump casing. A rotating liquid ring seals the impeller on the front and seals its blades against one another. In order to keep the liquid ring stable, water is also permanently sucked into the pump chamber and is discharged together with air.

The excentrical arrangement of the impeller in the casing creates variable compression chambers between the impeller blades during rotation, which causes the conveyed air to be compressed within a full revolution.

A water ring is required to create a tight seal between the tip of the impeller blades and the pump housing. There are (3) different ways a liquid ring pump utilizes the sealing water.

  • “Once thru re-circulating” system: sealing water is introduced into the pump, discharged, and sent directly down the drain. This type of system is very simple in design but  does require large amounts of water to operate.
  • “Partial re-circulating” system: sealing water is introduced into the pump and discharged. Some of the discharged water is re-circulated and used again to seal the pump. This type of system is relatively simple in design and, since some of the water is re-used, it does not require as much water as the “once thru” to operate.
  • “Total re-circulating” system: The discharged water is cooled in a water-to-water heat exchanger utilizing chilled water as a cooling media. The cooled water is then used again to seal the pump. Only a small amount of fresh purge water is needed to prevent bacterial growth.

"Economizer V" water-sealed liquid ring systems with field adjustable water recirculation.

Water-sealed liquid ring vacuum pump systems have always enjoyed a good reputation based on exceptional reliability, low maintenance and a very long field-proven record. However, they normally require a continuous supply of water when they run which can be costly when water and sewage costs are added.

EMSE Corporation has developed “Economizer V” – a line of water-sealed liquid ring vacuum systems that offer a unique feature: field selectable and adjustable amount of partial water recirculation up to 95% without the use of heat exchangers and chilled water. This feature will dramatically minimize operating expenses without the added cost to the initial price, installation and maintenance.

Advantages: Disadvantages:
  • Very good choice for a dedicated anesthesia evacuation system
  • Simple, time-proven design
  • Capable of taking slugs of water
  • Low maintenance
  • Low operating costs
  • Dependence on a reliable supply of water
  • Good water quality is critical to avoid premature failures due to scale build-up

System Selections

Duplex Systems


System Model Number Pump HP System Tank Size Pump SCFM at 19″Hg System SCFM at 19″Hg Catalog Cuts Suggested Specs
1DWSH1.5T120V 1.5 Duplex
120 6.2 6.2* Catalog Cuts Specs
1DWSH3T120V 3 120 13.5 13.5* Catalog Cuts Specs
1DWSC4T120V 4 120 21.5 21.5* Catalog Cuts Specs
1DWSH5T120V 5 120 27.7 27.7* Catalog Cuts Specs
1DWSH7.5T200V 7.5 120 42.7 42.7* Catalog Cuts Specs
1DWSH10T120V 10 200 56.2 56.2* Catalog Cuts Specs
1DWSC15T200V 15 200 80.3 80.3* Catalog Cuts Specs
1DWSH15B200T 15 Duplex Base Mounted 200 90.5 90.5* Catalog Cuts Specs
1DWSH20B200T 20 200 123.0 123.0* Catalog Cuts Specs
1DWSH30B200T 30 200 175.0 175.0* Catalog Cuts Specs
*System capacities are shown without the reserve pump per NFPA 99