The work proves the effectiveness of the parameter space investigation method for solving inverse tasks of multi-criteria identification by the example
of an external gear pump with a transparent casing developed at the Wroclaw Polytechnica. The mathematical model of the object of investigation was
improved by introducing the equations of radial clearance and normal backlash, which increased its adequacy and allowed to determine three input
data that are absent in the technical documentation. The found values of the dedendum coefficient, backlash and radial clearance together with other
known input data allow to build the 3D computer model for further investigation of pump working processes in the CFD program.
