Patent ID: 6807845
Filing Date: 2004-10-26
Classification: G01B

Abstract:
A measurement apparatus for determining the position of an object relative to a reference surface, said measurement apparatus comprising:at least one measurement nozzle, said at least one measurement nozzle having an outlet opening located in a reference surface; at least two reference nozzles; at least one measurement device, said at least measurement device being adapted to acquire one state variable of flow rate, pressure and speed of the air upstream of said at least one measurement nozzle; a compressed air source for providing air at a certain feed pressure, wherein an effective outlet surface of at least one of said at least two reference nozzles is adjustable incrementally and the effective outlet surface of at least another one of the at least two reference nozzles is adjustable continuously; and wherein at least one of at least one reference nozzle that is adjustable incrementally comprises a plurality of individually actuated nozzles, said plurality of individually actuated nozzles having different effective outlet surfaces.