Flotation nozzle for web handling equipment

摘要

A nozzle box assembly for use in apparatus for supporting and guiding a horizontally moving web of sheet material comprises an elongated housing defining an elongated, first chamber which extends centrally and axially of the housing. Second and third chambers are located on opposite sides of the first chamber and extend parallel thereto. The second and third chambers each include an elongated discharge nozzle slot extending parallel to the first chamber and discharging on opposite sides of a Coanda surface. Pressurized gas is supplied to the first chamber and a first and a second plurality of flow openings in the housing respectively act to conduct gas from the first chamber to the second and third chambers in a particularly uniform manner. First and second independently operable valves are mounted in the housing for controlling gas flow through the first and said second plurality of flow openings to thereby control flow to the second and third chambers and from the discharge nozzle slots. An alternate embodiment also shows a discharge slot centrally of the Coanda surface and parallel to the discharge slots from the second and third chambers. This Coanda surface slot is also controlled by an independently operable valve.