Zone-forming apparatus

An apparatus for conditioning a first zone of fluid and substantially isolating the first zone from a surrounding second zone, the apparatus comprising:

• fluid regulating means positioned at a first end of the first zone and for conditioning fluid contained in the first zone, said fluid regulating means circulating the first zone fluid through said fluid regulating means and substantially throughout the first zone;
• a jet-stream generating means for generating a stream of fluid at a second end of the first zone;
• a guide member positioned at the second end of the first zone and downstream of said jet-stream generating means, said guide members having a guide surface means for substantially guiding said stream of fluid into a canopy-like film layer, said canopy-like film layer initially guided in a radially outward direction and radially beyond said guide surface means, said guide surface means also for guiding said canopy-like film layer in an axial direction, said canopy-like film layer and said guide member defining and isolating the first zone of conditioned fluid from the surround second zone of fluid, the zone being defined by said stream of fluid being guided into said canopy-like film layer, said zone having a diameter larger than said guide member.