a continuously operating press for the production of particle boards , fiber boards and similar wood boards and plastic boards , wherein a spherical geometrical deformation of the press / heating platen in the longitudinal and transverse directions with the hydraulic actuators in positive or non - positive engagement with the press / heating platen is set during start - up or production by means of different actuating forces in the longitudinal and transverse directions , the setting process being independent of the reaction forces of pressing stock , wherein , to allow a convex bending deformation to be set at the maximum pressing force , the central actuators in each row of actuators are dimensioned to give 105 % to about 150 % of the maximum pressing force in relation to the outer actuators , and wherein each row of actuators has a position sensor system comprising a feeler rod , a reference gauge bar , a lever mechanism and a measured - value transmitter with a position sensor for the press - nip actual value in the center of the press / heating platen arranged between the web plates , underneath the actuators and outside the area in which the heat might exert a critical influence .