Building material manufacturing apparatus and building material manufacturing method

A raw material mat forming method, useful for manufacturing a building material, wherein

• using a sieve portion including a receiving and sending sheet with no sieve openings, onto which a building raw material is to be dropped, and at least one sieve sheet with sieve openings that is located below the receiving and sending sheet, the receiving and sending sheet and the sieve sheet being able to perform undulating motion and the receiving and sending sheet and the sieve sheet being inclined and arranged side by side in the direction of the inclination, and
• a receiving tool for receiving the building raw material that has passed through the sieve openings of the sieve portion,
• in a state in which the receiving and sending sheet and the at least one sieve sheet are performing undulating motion,
• the building raw material is dropped onto the receiving and sending sheet,
• the building raw material is moved from the receiving and sending sheet onto the at least one sieve sheet,
• sieving of the building raw material is performed by the at least one sieve sheet, and
• the building raw material that has passed through the sieve openings of the at least one sieve sheet is accumulated on the receiving tool, and a mat with at least one layer is formed,
• wherein
• the sieve portion includes, as the sieve sheet, a fine sieve sheet with small sieve openings, and a coarse sieve sheet that is located below the fine sieve sheet and has large sieve openings, and
• a mat including a layer formed by the building raw material that has passed through the sieve openings of the fine sieve sheet and a layer formed by the building raw material that has passed through the sieve openings of the coarse sieve sheet is formed on the receiving tool,
• wherein the sieve portion further includes a relay sheet with no sieve openings that is located between the fine sieve sheet and the coarse sieve sheet and can perform undulating motion, and
• in a state in which the relay sheet is performing undulating motion in addition to the receiving and sending sheet and the sieve sheet,
• the building raw material that does not pass through the sieve openings of the fine sieve sheet is moved onto the coarse sieve sheet via the relay sheet.