February 7, 2003
Is it possible to circumvent Coanda effect?
Coanda effect is rigorous. For those who forgot what it is about we may remind that Coanda effect states: every moving liquid tends to be retained against a surface that limits its motion. Because of intermolecular adhesion and atmospheric pressure any liquid that is being poured out of some vessel is reluctant to leave its walls. As a result, it drops on a table-cloth. It is especially irritating when drops of red wine or coffee fall on a table-cloth.
Designers of the Danish company Eva Solo do not agree with the laws of nature. Or it is better to say that they find ingenious methods to circumvent them. A drop from a coffee-pot will never spoil a snow-white table-cloth, because there is a special trap for it. The thing is that an additional nozzle is fixed within the coffee-pot spout. When the coffee-pot is inclined, the major portion of liquid flows through the internal nozzle.
When the coffee-pot is standing upright, the drop formed in accordance with Coanda effect will flow on the external surface of the INTERNAL nozzle. It will not fall on the table-cloth but will return into the pot through a small hole between the nozzle and the spout.
Thereby Coanda, that causes a harmful effect, is circumvented by passing to a bi-system and by using inventive power.
One can see the flash presentation of the last drop catching on the Eva Solo site. http://www.evadenmark.com/evasoloweb/products-vacuumflash.html