Venturis - Tech Talk 63
A well-designed venturi working in shallow water to aspirate air may cause as little as 15 percent additional head pressure and as little as 10 percent reduction in volume pumped. Therefore, a venturi can be a very economical device to operate, especially when it completely eliminates another piece of equipment, such as a chemical metering pump, an air pump or an ozone unit's air pump. They are particularly useful when injecting chemicals and gases that are aggressive in nature and would require special materials for the pumping device.
As a venturi draws air into a depth of about 2 feet, there will be increased water pressure resistance and a reduction in volume pumped. When used with low-pressure pumps, the increase in head causes such a large reduction in volume that the venturi application becomes impractical. When sucking air, the deeper the depth, the greater the pressure needed.
When installed properly, venturi injectors can transfer ozone into water with efficiencies as high as 99 percent. Venturis have no moving parts and provide trouble-free operation.