Apparatus and method for transferring particulate material
An apparatus for transferring, at high speed and in a very effective and accurate manner, particulate material from a feeder into reservoirs of a moving endless surface, e.g. a drum, by use of a pressure means, e.g. a specific three-dimensional plate, for applying pressure onto said particulate material present between said plate and said moving endless surface, and then transferring the particulate material with said moving endless surface with reservoirs to a substrate; the apparatus and method being particularly useful for the production of absorbent structures for absorbent articles.
1. A method for making a structure that comprises particulate material supported or enclosed by a substrate material, including the steps of:
a) feeding a first particulate material with a feeder to a first moving endless surface with a plurality of reservoirs, adjacent said feeder;
b) allowing flow of said particulate material, or part thereof, into a volume space present between said first moving endless surface and a three-dimensional plate, adjacent said feeder and adjacent and opposing said first moving endless surface; and contacting a part of said particulate material with said three dimensional plate, said plate having a first plate face adjacent said first moving endless surface, and said plate face having:
i) a first surface area substantially parallel to said first moving endless surface; and
ii) a second surface area neighboring said first surface area, being downstream (in MD) from said first surface area, said second surface area being non-parallel to said first moving endless surface and leading from said first surface area towards said first moving endless surface, said first surface area and said second surface area are connected to one another under an angle, and said second surface area having an average angle with said first moving endless surface from about 10° to about 80°;
c) applying a pressure with said plate onto at least a portion of said particulate material present between said first plate face and said first moving endless surface, guiding said material into said reservoirs;
d) transferring said particulate material in said reservoirs of said first moving endless surface directly or indirectly to a second moving endless surface, being, or carrying, said substrate material; and
e) depositing said particulate material onto said substrate material.
2. A method according to claim 1 , wherein said pressure application step c) includes: firstly applying a pressure, with said first surface area of said plate, said pressure being substantially perpendicular to the direction of movement of the first moving endless surface (MD), thereby guiding at least a first portion of said particulate material into said reservoirs; and secondly, applying a pressure with said plate face's second surface area, said pressure being non-perpendicular to the direction of movement of the first moving endless surface (MD), thereby guiding at least a second portion of said particulate material into said reservoirs.
3. A method according to claim 1 , wherein said plate face has a third surface area substantially parallel to the first moving endless surface and in close proximity thereto than said first surface area, said third surface area guiding a third portion of said particulate material into said reservoirs and/or aiding retention of said particulate material in said reservoirs.
4. A method according to claim 1 , wherein the pressure is controlled by use of a pressure control means, including an actuator.
5. A method according to claim 1 , wherein said first moving endless surface has a surface speed of at least about 2 m/s.
6. A method according to claim 5 , wherein said first moving endless surface has a surface speed of at least about 3 m/s.
7. A method according to claim 6 , wherein said first moving endless surface has a surface speed of at least about 4.5 m/s.
8. A method according to claim 7 , wherein said first moving endless surface has a surface speed of at least about 6.0 m/s.
9. A method according to claim 8 , wherein said first moving endless surface has a surface speed of at least about 7.0 m/s.
10. A method according to claim 1 , wherein said first moving endless surface has a speed of at least about 1000 parts per minute.
11. A method according to claim 1 , wherein said particulate material has a mass median particle size from about 150 microns to about 1000 microns.
12. A method according to claim 11 , wherein said particulate material has a mass median particle size from about 200 microns to about 700 microns.