Coating system

In a system for continuous application of a liquid coating material onto the surfaces of successive units of material having varying cross-sectional dimensions, a coating chamber substantially closed to the atmosphere for containing a substantial head of liquid coating material, said coating chamber defining rectangular inlet and outlet apertures therein generally conforming to the dimensions of the largest cross-section of material to be coated in said chamber, said apertures being located on opposite sides of said chamber in substantial horizontal alignment with each other and at a level in said chamber where substantial hydrostatic pressure of said liquid coating material will be maintained;

• guide means mounted in said coating chamber between said inlet and outlet apertures and adapted to contact the bottom of each unit of material passing through said chamber to guide said material between said apertures and to position the bottom surface of exiting portions of said material a small distance above the bottom edge of said outlet aperture;
• port defining means mounted over each of said inlet and outlet apertures for providing entrance and exit ports of adjustable dimensions, each of said port defining means comprising a pair of vertical gates and a pair of horizontal gates, mounting means for mounting the bottom one of said vertical gates in a fixed position with a top edge aligned with the bottom edge of an associated aperture and for mounting each of said other gates in sliding relation with a different one of the other edges of said associated aperture, positioning means for setting an initial position of each of said other gates to establish initial minimum dimensions of the exit port slightly larger than cross-sectional dimensions of units of material to be coated and initial minimum dimensions of the entrance port equal to the cross-sectional dimensions of said material, and spring means for biasing said gates toward said initial positions;
• means acting continuously above the level of liquid coating material in said chamber to produce a pressure differential between the interior and exterior of said chamber sufficient to induce a continuous flow of air into said chamber about the periphery of portions of material positioned within said entrance and exit ports and upwardly through said liquid coating material in said chamber, said flow of air serving to seal said ports, to remove excess amounts of said coating material on surface portions of said units exiting said chamber, and at least partly to dry said coating on said exiting surface portions of said units;
• and a dimension sensing element, second mounting means for mounting said dimension sensing element inside said chamber in position-communicating-relation with said slidably mounted vertical gate at said outlet aperture, and including element positioning means for setting an initial position of said dimension sensing element a short distance above the top surface of a unit of material of normal dimension extending through said chamber, said dimension sensing element being adapted to contact the leading end of a unit of material having a thickness greater than said normal dimension and thereupon automatically to adjust the position of said slidably mounted vertical gate at said outlet aperture to maintain a small air gap between the bottom edge of said gate and the top surface of said unit of material passing through said exit port, whereby the integrity of the coating material on said associated surface is maintained.

In a system for continuous application of a liquid coating material onto the surfaces of successive units of material having varying cross-sectional dimensions, a coating chamber substantially closed to the atmosphere for containing a substantial head of liquid coating material, said coating chamber defining rectangular inlet and outlet apertures therein generally conforming to the dimensions of the largest cross-section of material to be coated in said chamber, said apertures being located on opposite sides of said chamber in substantial horizontal alignment with each other and at a level in said chamber where substantial hydrostatic pressure of said liquid coating material will be maintained;

• guide means mounted in said coating chamber between said inlet and outlet apertures and adapted to contact the bottom of each unit of material passing through said chamber bottom surface of exiting portions of said material a small distance above the bottom edge of said outlet aperture;
• port defining means mounted over each of said inlet and outlet apertures for providing entrance and exit ports of adjustable dimensions, each of said port defining means comprising a pair of vertical gates and a pair of horizontal gates, mounting means for mounting the bottom one of said vertical gates in a fixed position with a top edge aligned with the bottom edge of an associated aperture and for mounting each of said other gates in sliding relation with a different one of the other edges of said associated aperture, positioning means for setting an initial position of each of said other gates to establish initial minimum dimensions of the exit port slightly larger than cross-sectional dimensions of units of material to be coated and initial minimum dimensions of the entrance port equal to the cross-sectional dimensions of said material, and spring means for biasing said gates toward said initial positions;
• means acting continuously above the level of liquid coating material in said chamber to produce a pressure differential between the interior and exterior of said chamber sufficient to induce a continuous flow of air into said chamber about the periphery of portions of material positioned within said entrance and exit ports and upwardly through said liquid coating material in said chamber, said flow of air serving to seal said ports, to remove excess amounts of said coating material on surface portions of said units exiting said chamber, and at least partly to dry said coating on said exiting surface portions of said units;
• each of said slidably mounted vertical gates being generally rectangular with a width generally corresponding to the width of said apertures and a height at least greater than the height of said apertures;
• each of said horizontal gates being generally rectangular with a height generally corresponding to the height of said apertures and a width at least greater than one-half the width of said apertures;
• and said mounting means comprising a mounting frame having a top spacer bar mounted to said chamber above said associated aperture, a bottom spacer bar mounted along with said fixed bottom gate to said chamber below said associated aperture, and a pair of vertical gate retaining bars mounted to said spacer bars at the sides of said associated aperture and having an inwardly extending front lip, said spacer bars and said retaining bars forming a channel at each side of said aperture for receiving and retaining said horizontal gates in sliding relation with the side edges of said aperture, and said front lips of said retaining bars and said top spacer bar forming a channel for receiving and retaining said top vertical gate in sliding relation with the top edge of said aperture.

In a system for continuous application of a liquid coating material onto surfaces of successive units of material, a coating chamber substantially closed to the atmosphere for containing a substantial head of liquid coating material, port defining means for providing entrance and exit ports in said coating chamber having configurations generally corresponding to the cross-sectional configuration of units of material to be coated in said chamber and located at a level in said chamber where substantial hydrostatic pressure of said liquid coating material will be maintained;

• and a masking element mounted within said chamber and extending between said entrance and exit ports, said masking element being configured to form a pocket adjacent a preselected portion of at least one surface of units of material passing through said chamber;
• and means acting continuously above the level of liquid coating material in said chamber to produce a pressure differential between the interior and exterior of said chamber sufficient to induce a continuous flow of air into said chamber about the periphery of portions of material positioned within said entrance and exit ports and across said preselected surface portion of said units and thence upwardly through said liquid coating material in said chamber, said flow of air serving to seal said ports, to remove excess amounts of said coating material on surface portions of said units exiting said chamber, at least partly to dry said coating on said exiting surface portions of said units, and to preclude application of said coating material on said preselected surface portion of said units.

In a system for continuous application of a liquid coating material onto the surfaces of successive units of material having varying cross-sectional dimensions, a coating chamber substantially closed to the atmosphere for containing a substantial head of liquid coating material, said coating chamber defining an inlet aperture and an outlet aperture therein generally conforming to the dimensions of the largest cross section of material to be coated in said chamber, said apertures being located on opposite sides of said chamber in substantial alignment with each other and at a level in said chamber where substantial hydrostatic pressure of said liquid coating material will be maintained;

• port defining means mounted over each of said inlet and outlet apertures for providing entrance and exit ports of adjustable dimensions, each of said port defining means comprising at least one gate, gate mounting means for mounting said gate in sliding relation with one of the edges of an associated aperture, positioning means for setting an initial position of said gate, and spring means for biasing said gate toward said initial position;
• means acting continuously above the level of liquid coating material in said chamber to produce a pressure differential between the interior and exterior of said chamber sufficient to induce a continuous flow of air into said chamber about the periphery of portions of material positioned within said entrance and exit ports and upwardly through said liquid coating material in said chamber;
• and a masking element mounted within said chamber and extending between said entrance and exit ports, said masking element being configured to form a pocket adjacent a preselected portion of at least one surface of units of material passing through said chamber, said pocket communicating with said entrance and exit ports such that a continuous flow of air passes through said pocket and across said preselected surface portion of units of material to preclude application of said liquid coating material on said preselected surface portions.