Method of making a composite cast iron dryer or the like

Claim 1

The method of using a gas torch in the spray-coating of a convex cylindrical metal workpiece surface, which comprises rotating the workpiece on a horizontal axis, orienting the torch for discharge generally horizontally and radially toward the cylindrical surface at a given longitudinal location and at a first general peripheral location, adding a flow of metal powder to the torch flow, whereby a coating of metal is locally deposited on the workpiece surface in the course of workpiece rotation, concurrently abrasively scouring the cylindrical surface at said longitudinal location and at a second general peripheral location angularly offset from the region of instantaneous torch discharge, the direction of workpiece rotation being such that the cylindrical surface moves downward past the region of torch discharge thereon, and horizontally traversing along the workpiece the longitudinal region of torch discharge and abrasive scouring, the effective longitudinal extent of the region of torch discharge and abrasive scouring being relatively great compared to the traverse advance per workpiece revolution, whereby multiple coats of sprayed metal are applied to the workpiece for a given traverse, and whereby in the course of said given traverse the abrasive scouring step is performed after application of each coat and before application of the next coat, to thereby remove metal powder which is not densely compacted and fused between coat applications so that more densely compacted sprayed metal will characterize the coat produced in the course of continuous rotation of the workpiece.

Claim 2

The method of using a gas torch in the spray-coating of a convex cylindrical metal workpiece surface, which comprises rotating the workpiece on a horizontal axis, orienting the torch for discharge generally horizontally and radially toward the cylindrical surface at a given longitudinal location and at a first general peripheral location, adding a flow of metal powder to the torch flow, whereby a coating of metal is locally deposited on the workpiece surface in the course of workpiece rotation, concurrently abrasively scouring the cylindrical surface at said longitudinal location and at a second general peripheral location angularly offset from the region of instantaneous torch discharge, the direction of workpiece rotation being such that the cylindrical surface moves downward past the region of torch discharge thereon, and horizontally traversing along the workpiece the longitudinal region of torch discharge and abrasive scouring, the effective longitudinal extent of the region of torch discharge and abrasive scouring being relatively great compared to the traverse advance per workpiece revolution, whereby multiple coats of sprayed metal are applied to the workpiece for a given traverse, and whereby in the course of said given traverse the abrasive scouring step is performed after application of each coat and before application of the next coat, to thereby remove metal powder which is not densely compacted and fused between coat applications so that more densely compacted sprayed metal will characterize the coat produced in the course of continuous rotation of the workpiece.

Claim 5

The method of conditioning the external convex cylindrical surface of a Yankee-dryer or the like roll, which comprises passing a flow of steam through the roll until achievement of a roll-surface temperature of at least substantially 200° F., rotating the roll on a horizontal axis, directing a flaming gas-torch flow generally horizontally and radially toward the cylindrical surface at a given longitudinal location at a first general peripheral location on the side for which said cylindrical surface is moving downwardly, supplying a flow of metal powder to the torch flow, whereby a coating of metal is locally deposited on the cylindrical surface in the course of roll rotation, concurrently abrasively scouring the cylindrical surface at said longitudinal location and at a second general peripheral location angularly offset from the region of instantaneous torch flow, and horizontally traversing along the cylindrical surface the longitudinal region of torch discharge and abrasive scouring, the effective longitudinal extent of the region of torch discharge and abrasive scouring being relatively great compared to the traverse advance per roll revolution, whereby multiple coats of sprayed metal are applied to the roll for a given traverse, and whereby in the course of said given traverse, the abrasive scouring step is performed after application of each coat and before application of the next coat, to thereby remove metal powder which is not densely compacted and fused between coat applications so that more densely compacted sprayed metal will characterize the coat produced in the course of continuous rotation of the roll.

Claim 6

The method of conditioning the external convex cylindrical surface of a Yankee-dryer or the like roll, which comprises passing a flow of steam through the roll until achievement of a roll-surface temperature of at least substantially 200° F., rotating the roll on a horizontal axis, directing a flaming gas-torch flow generally horizontally and radially toward the cylindrical surface at a given longitudinal location at a first general peripheral location on the side for which said cylindrical surface is moving downwardly, supplying a flow of metal powder to the torch flow, whereby a coating of metal is locally deposited on the cylindrical surface in the course of roll rotation, concurrently abrasively scouring the cylindrical surface at said longitudinal location and at a second general peripheral location angularly offset from the region of instantaneous torch flow, and horizontally traversing along the cylindrical surface the longitudinal region of torch discharge and abrasive scouring, the effective longitudinal extent of the region of torch discharge and abrasive scouring being relatively great compared to the traverse advance per roll revolution, whereby multiple coats of sprayed metal are applied to the roll for a given traverse, and whereby in the course of said given traverse, the abrasive scouring step is performed after application of each coat and before application of the next coat, to thereby remove metal powder which is not densely compacted and fused between coat applications so that more densely compacted sprayed metal will characterize the coat produced in the course of continuous rotation of the roll.

Claim 14

The method of using a gas torch in the spray-coating of a convex cylindrical metal workpiece surface, which comprises rotating the workpiece on a horizontal axis, orienting the torch for discharge generally radially toward the cylindrical surface at a given longitudinal location and at a first general peripheral location, adding a flow of metal powder to the torch flow, whereby a coating of metal is locally deposited on the workpiece surface in the course of workpiece rotation, concurrently abrasively scouring the cylindrical surface at said longitudinal location and at a second general peripheral location angularly offset from the region of instantaneous torch discharge, and horizontally traversing along the workpiece the longitudinal region of torch discharge and abrasive scouring, the effective longitudinal extent of the region of torch discharge and abrasive scouring being relatively great compared to the traverse advance per workpiece revolution, whereby multiple coats of sprayed metal are applied to the workpiece for a given traverse, and whereby in the course of said given traverse the abrasive scouring step is performed after application of each coat and before application of the next coat, to thereby remove metal powder which is not densely compacted and fused between coat applications so that more densely compacted sprayed metal will characterize the coat produced in the course of continuous rotation of the workpiece.

Claim 15

The method of using a gas torch in the spray-coating of a convex cylindrical metal workpiece surface, which comprises rotating the workpiece on a horizontal axis, orienting the torch for discharge generally radially toward the cylindrical surface at a given longitudinal location and at a first general peripheral location, adding a flow of metal powder to the torch flow, whereby a coating of metal is locally deposited on the workpiece surface in the course of workpiece rotation, concurrently abrasively scouring the cylindrical surface at said longitudinal location and at a second general peripheral location angularly offset from the region of instantaneous torch discharge, and horizontally traversing along the workpiece the longitudinal region of torch discharge and abrasive scouring, the effective longitudinal extent of the region of torch discharge and abrasive scouring being relatively great compared to the traverse advance per workpiece revolution, whereby multiple coats of sprayed metal are applied to the workpiece for a given traverse, and whereby in the course of said given traverse the abrasive scouring step is performed after application of each coat and before application of the next coat, to thereby remove metal powder which is not densely compacted and fused between coat applications so that more densely compacted sprayed metal will characterize the coat produced in the course of continuous rotation of the workpiece.

Claim 16

The method of conditioning the external convex cylindrical surface of a Yankee-dryer or the like roll, which comprises passing a flow of steam through the roll until achievement of a roll-surface temperature of at least substantially 200° F., rotating the roll on a horizontal axis, directing a flaming gas-torch flow from one side of and generally radially toward the cylindrical surface at a given longitudinal location and at a first general peripheral location, supplying a flow of metal powder to the torch flow, whereby a coating of metal is locally deposited on the cylindrical surface in the course of roll rotation, concurrently abrasively scouring the cylindrical surface at said longitudinal location and at a second general peripheral location angularly offset from the region of instantaneous torch flow, and horizontally traversing along the cylindrical surface the longitudinal region of torch discharge and abrasive scouring; the effective longitudinal extent of the region of torch discharge and abrasive scouring being relatively great compared to the traverse advance per roll revolution, whereby multiple coats of sprayed metal are applied to the roll for a given traverse, and whereby in the course of said given traverse the abrasive scouring step is performed after application of each coat and before application of the next coat, to thereby remove metal powder which is not densely compacted and fused between coat applications so that more densely compacted sprayed metal will characterize the coat produced in the course of continuous rotation of the roll.

Claim 17

The method of conditioning the external convex cylindrical surface of a Yankee-dryer or the like roll, which comprises passing a flow of steam through the roll until achievement of a roll-surface temperature of at least substantially 200° F., rotating the roll on a horizontal axis, directing a flaming gas-torch flow from one side of and generally radially toward the cylindrical surface at a given longitudinal location and at a first general peripheral location, supplying a flow of metal powder to the torch flow, whereby a coating of metal is locally deposited on the cylindrical surface in the course of roll rotation, concurrently abrasively scouring the cylindrical surface at said longitudinal location and at a second general peripheral location angularly offset from the region of instantaneous torch flow, and horizontally traversing along the cylindrical surface the longitudinal region of torch discharge and abrasive scouring; the effective longitudinal extent of the region of torch discharge and abrasive scouring being relatively great compared to the traverse advance per roll revolution, whereby multiple coats of sprayed metal are applied to the roll for a given traverse, and whereby in the course of said given traverse the abrasive scouring step is performed after application of each coat and before application of the next coat, to thereby remove metal powder which is not densely compacted and fused between coat applications so that more densely compacted sprayed metal will characterize the coat produced in the course of continuous rotation of the roll.