System and method for recycling planar objects

A system for recycling planar objects having a first major surface and an opposing, second major surface, the planar objects comprising compressed mineral fiber material, the system comprising:

• a conveyor arranged to sequentially covey the planar objects one by one through a number of stations along a conveyor direction, the number of stations at least comprising:
• a thickness measurement station arranged to determine a property related to thickness and associated to each of the planar objects being conveyed through the thickness measurement station, and
• a sound measurement station arranged to determine a property related to sound absorption and associated to each of the planar objects being conveyed through the sound measurement station, the sound measurement station comprising,
• a sound reflecting surface arranged to back the first major surface of each planar object being conveyed through the sound measurement station,
• a sound emitter arranged to emit sound towards the sound reflecting surface,
• a sound receiver arranged to receive sound reflected from the sound reflecting surface, and
• a converter arranged to determine the property related to sound absorption based on the emitted sound and the reflected sound, and
• a sorting station arranged to sort the planar objects based on their respective determined properties in to a plurality of fractions.

A method for recycling planar objects having a first major surface and an opposing, second major surface, the planar objects comprising compressed mineral fiber material, the method comprising:

• sequentially conveying the planar objects one by one through a number of stations along a conveyor direction to determine a number of properties,
• determining a property related to thickness and associated to each of the planar objects using a thickness measurement station while conveying each of the planar objects through the thickness measurement station,
• determining a property related to sound absorption and associated to each of the planar objects using a sound measurement station while conveying each of the planar objects through the sound measurement station, wherein determining the property related to sound absorption comprises;
• backing the first major surface of a planar object being conveyed through the sound measurement station on a sound reflecting surface,
• emitting sound towards the sound reflective surface, such that the emitted sound enters the planar object at the second major surface and propagates through the planar object to the sound reflective surface,
• receiving sound exiting the second major surface of the planar object and being reflected by the sound reflecting surface, and
• determining the property related to sound absorption based on the emitted sound and the received sound, and
• sorting the planar objects based on their respective determined properties in to a plurality of fractions using a sorting station, wherein at least one of the plurality of fractions is used for assembling planar objects comprising compressed mineral fiber material.