Dosing device for dosing a granular material, spraying device and method for applying a granular material to a substrate

A method for applying a granular material (16) to a surface of a substrate (112), the method comprising supplying the granular material (16) and the substrate (112) to a spraying device (100), and applying the granular material (16) to the surface of the substrate (112) by the spraying device (100),

• wherein the substrate (112) is a substrate of a switchable window,
• wherein the spraying device (100) comprises a dosing device (10), the dosing device (10) supplying a gas stream comprising the granular material (16), at least one nozzle (108), at least one supply line (104) connecting the dosing device (10) to the at least one nozzle (108) and means for moving a substrate (112) relative to the at least one nozzle (108),
• and wherein the dosing device (10) comprises
• a reservoir (12) for storing the granular material (16),
• a dosing disc (20), and
• a suction device (24), wherein
• the dosing disc (20) is rotatable around a rotational axis (22),
• the reservoir (12) has a dosing opening (14) facing the dosing disc (20),
• the dosing opening (14) being arranged above the dosing disc (20) such that a dosing gap is formed between a surface of the dosing disc (20) and a surface (26) surrounding the dosing opening (14), the dosing opening (14) being arranged eccentric with respect to the rotational axis (22),
• the suction device (24) having an opening (25) facing the dosing disc (20), the opening (25) being arranged above the dosing disc (20) and being arranged eccentric with respect to the rotational axis (22),
• the size of the dosing gap being such that a monolayer (18) of the particles (17) of the granular material (16) is dosed from the reservoir (12) through the dosing opening (14) onto the surface of the dosing disc (20),
• the suction device (24) being constructed and arranged such that the monolayer (18) of particles (17) is being sucked into the suction device (24) and mixed with a gas stream when the particles (17) are being transported to the suction device (24) by rotation of the dosing disc (20).

A spraying device (100) for applying a granular material (16) to a surface of a substrate (112), the spraying device (100) comprising a dosing device (10), the dosing device (10) supplying a gas stream comprising the granular material (16), at least one nozzle (108), at least one supply line (104) connecting the dosing device (10) to the at least one nozzle (108) and a conveyor or substrate carrier for moving a substrate (112) relative to the at least one nozzle (108),

• wherein the spraying device (100) comprises at least one supply line which is at least partially constructed from an electrically conductive material such that the particles are charged by collisions with the conductive material of the supply line thereby electrostatically charging the particles (17) of the granular material (16),
• and wherein the dosing device (10) comprises
• a reservoir (12) for storing the granular material (16),
• a dosing disc (20), and
• a suction device (24), wherein
• the dosing disc (20) is rotatable around a rotational axis (22),
• the reservoir (12) has a dosing opening (14) facing the dosing disc (20),
• the dosing opening (14) being arranged above the dosing disc (20) such that a dosing gap is formed between a surface of the dosing disc (20) and a surface (26) surrounding the dosing opening (14), the dosing opening (14) being arranged eccentric with respect to the rotational axis (22),
• the suction device (24) having an opening (25) facing the dosing disc (20), the opening (25) being arranged above the dosing disc (20) and being arranged eccentric with respect to the rotational axis (22),
• the size of the dosing gap being such that a monolayer (18) of the particles (17) of the granular material (16) is dosed from the reservoir (12) through the dosing opening (14) onto the surface of the dosing disc (20),
• the suction device (24) being constructed and arranged such that the monolayer (18) of particles (17) is being sucked into the suction device (24) and mixed with a gas stream when the particles (17) are being transported to the suction device (24) by rotation of the dosing disc (20).