Liquid ring vacuum pumps are suction pumps. While the moving part, (the shaft and the impellers) which are mounted eccentric from the center axis of the pump casing. As the rotor, the shaft and the impellers turns the liquid in the pump casing forced outwards by centrifugal force. A liquid ring forms along the body wall. Because of the eccentricity of the rotor the cells between pump casing and the rotor blades are filled with liquid at different amounts. The cells which are in the top position are completely filled with liquid and as the impeller rotates through half a revolution the liquid is replaced by gas. As rotation continues the liquid forces the gas through the discharge port. This cycle is repeated for each cell of the impeller and results in a steady flowing source of vacuum.
SERVICE LIQUID SYSTEMS
During working, to eliminate the heat which is produced because of the compression of the sucked gases, must be supplied service liquid continuously. Generally water is used as service liquid. During working of the pump the temperature inside the pump increases, that’s why service liquid must be as cool as possible (below 15 ºC is suitable).
A) ONCE THROUGH-NO RECOVERY SEALANT SYSTEM
This connection is used where adequate sealant flow is available from outside source, or where contamination of sealant may be a problem.
B) PARTIAL RECIRCULATION
This connection is used to conserve sealant. Make up sealant is supplied from an outside source or water main. Remainder of sealant is supplied from recirculation tank.
C) TOTAL RECIRCULATION
This connection is used to conserve sealant, or where compatible sealant is not available from an outside source. Cooling is provided by running sealant through a heat exchanger. Separate cooling liquid or gas is required.
