Device and method for detection of foreign objects in a mat spread on a conveyor

A method for detecting at least one foreign object in a mat, the method comprising the steps of:

• providing that the mat is spread on a conveyor device in a process for producing a plurality of manufactured boards, the mat including (i) a plurality of fibers or a plurality of chips and (ii) at least one binding agent which are pressed under an increased temperature in a continuous press;
• using at least one first sensor device, which operates with a plurality of electromagnetic waves, a plurality of ultrasonic waves, a plurality of magnetic fields, or radiometry and which is directed at at least one spatial measuring area of the mat in order to detect the at least one foreign object, the at least one first sensor device recognizing a material of the at least one foreign object;
• aligning—if necessary, temporally offset—at least one second sensor device with the at least one spatial measuring area;
• and
• determining, by the at least one second sensor device, at least one foreign object dimension of the at least one foreign object.

A manufacturing process for producing a plurality of manufactured boards, the manufacturing process comprising the steps of:

• spreading, in a spreading station, a mat on a conveyor device, the mat including (i) a plurality of fibers or a plurality of chips and (ii) at least one binding agent;
• compacting the mat in a continuous press under an increased temperature;
• applying, between the spreading station and the continuous press, a method for detecting at least one foreign object in the mat, the method including the steps of:
• using at least one first sensor device, which operates with a plurality of electromagnetic waves, a plurality of ultrasonic waves, a plurality of magnetic fields, or radiometry and which is directed at at least one spatial measuring area of the mat in order to detect the at least one foreign object, the at least one first sensor device recognizing a material of the at least one foreign object;
• aligning—if necessary, temporally offset—at least one second sensor device with the at least one spatial measuring area;
• and
• determining, by the at least one second sensor device, at least one foreign object dimension of the at least one foreign object.