Patent ID: 6241463
Filing Date: 2001-06-05
Classification: F04D,F05D

Abstract:
A method of determining an operating level of a fan having an inlet nozzle, comprising the steps of:a) measuring an effective pressure difference .DELTA.p.sup.M.sub.w between two planes in the inlet nozzle or between a plane in the inlet nozzle and a location in the surroundings, a total pressure difference .DELTA.p.sup.M.sub.t between an intake side and a pressure side of the fan, and a shaft power P.sup.M.sub.w of a shaft driving the fan;b) determining from the effective pressure difference .DELTA.p.sup.M.sub.w the flow rate V by the relationshipV=.alpha.A((2+L /.rho.).DELTA.p.sup.M.sub.w +L ) (1)where .alpha. is a nozzle coefficient, A is a cross sectional area of the nozzle and .rho. is the density of gas displaced by the fan;c) comparing a target value of the total pressure difference .DELTA.p.sup.s.sub.t found from the flow rate V via an operational characteristic curve .DELTA.p.sub.t (V) with the measured total pressure difference .DELTA.p.sup.M.sub.t ;d) comparing a target value P.sup.s.sub.w for the shaft power found from the flow rate V via an operational characteristic curve P.sub.w (V with the measured power P.sup.M.sub.w ; ande) from the comparisons c) and d) establishing an operating level of the fan and a degree of accuracy of the operating level.