Coating humidification system
Described herein is a coating system comprising an applicator head that is configured to apply a coating to a surface of a workpiece, a shroud comprising a housing and an internal cavity located inside of the housing, and a humidifying apparatus comprising an output that is fluidly coupled to the shroud, wherein the humidifying apparatus configured to introduce a quantity of humid air to the internal cavity of the shroud.
1 . A method for coating a workpiece, the method comprising:
a) supplying humid air to a coating assembly, the coating assembly comprising:
an applicator head; and
a shroud comprising a housing defining an internal cavity, the housing comprising:
a top plate;
a first side plate extending downward from the top plate;
a second side plate extending downward from the top plate; and
the first side plate being opposite the second side plate;
a first axis A-A intersecting the first side plate and the second side plate;
whereby the applicator head is at least partially disposed inside of the internal cavity and the humid air is supplied to the internal cavity of the coating assembly;
b) conveying the workpiece on a conveyor configured to support the workpiece along a machine direction MD such that the conveyor and the applicator head move relative to each other, the machine direction MD being parallel to the first axis A-A of the shroud, while the workpiece is positioned between the first side plate and the second side plate; and
c) directing a coating composition onto a surface of the workpiece using the applicator head and exposing the surface of the workpiece to the humid air;
wherein during step a) the shroud is in a first state and wherein prior to step a) the shroud is in a second state, wherein in the second state the applicator head is located outside of the internal cavity.
2 . The method according to claim 1 , wherein steps a), b), and c) are performed concurrently.
3 . The method according to claim 1 , wherein the humid air is gravity fed to the internal cavity of the coating assembly.
4 . The method according to claim 1 , wherein the internal cavity is under a vacuum during step c).
5 . The method according to claim 1 , wherein the coating composition has a solids content ranging from about 60 wt. % to about 90 wt. % based on the total weight of the coating composition.
6 . The method according to claim 1 , wherein the humid air has a relative humidity ranging from about 60% to about 90%.
7 . The method according to claim 1 , wherein the humid air is supplied to the internal cavity at a rate of about 75 CFM to about 150 CFM.
8 . The method according to claim 1 , wherein the humid air is fed to the internal cavity at a rate ranging from about 8 lb./hr. to about 10 lb./hr.
9 . The method according to claim 1 , wherein the humid air in step a) is formed from a humidifying apparatus that comprises a steam generator and a mixing apparatus.
10 . The method according to claim 9 , wherein the mixing apparatus comprises a mixing chamber and an air-moving device.
11 . The method according to claim 10 , wherein the air is fed to the mixing chamber from the air-moving device and water vapor is fed to the mixing chamber from the steam generator, whereby the air and water vapor are blended to form the humid air.
12 . The method according to claim 10 , wherein the air is fed to the mixing chamber at a rate ranging from about 550 CFM to about 650 CFM.
13 . The method according to claim 10 , wherein the water vapor is fed to the mixing chamber at a rate ranging from about 9 lb./hr. to about 13 lb./hr.
14 . The method according to claim 1 , wherein the shroud comprises a baffle located in the internal cavity, and wherein during step c) the baffle redirects condensation from the humid air away from the surface of the workpiece.
15 . The method according to claim 1 , wherein the shroud moves relative to the applicator head to transition between the first state and the second state.
16 . The method according to claim 1 , further comprising a support apparatus configured to support the workpiece, wherein the applicator head and support apparatus move relative to each other.
17 . The method of claim 1 , wherein the top plate comprises a port that fluidly couples the internal cavity to an output of a humidifying apparatus, the humid air being supplied by gravity feed through the port, and wherein a baffle within the internal cavity at least partially overlaps the port and includes a cutout formed into a distal edge and a wall extending upward from the baffle that extends through the port and above the top plate, the baffle and the wall being configured to divert condensation away from an applicator nozzle of the applicator head.
18 . The method of claim 1 , wherein bottom edges of the first side plate and the second side plate are located beneath the conveyor during coating, and wherein at least one of the first side plate and the second side plate includes a stepped edge profile configured to receive at least a portion of an edge of the workpiece.
19 . The method of claim 1 , wherein the shroud transitions between-a first state and a second state the first state and the second state by vertically moving relative to the applicator head, and wherein a first securing element on the shroud interlocks with a second securing element on a support frame in the first state and is not interlocked in the second state.