Process and apparatus for boiler tube panel welding and straightening

An apparatus for depositing an overlay weld on a boiler tube panel comprising a plurality of tubes with adjacent tubes joined together with membranes therebetween, the apparatus comprising:

• means for supporting the boiler tube panel during overlay welding thereof, the supporting means comprising:
• an elongate frame sized to accommodate the boiler tube panel and horizontally support the boiler tube panel by contacting a first surface of the boiler tube panel while an oppositely-disposed second surface thereof faces upward;
• means for securing oppositely-disposed longitudinal ends and oppositely-disposed transverse edges of the boiler tube panel to the frame;
• at least one welding assembly mounted adjacent the frame and adapted for travel along the frame in a longitudinal direction of the boiler tube panel, the welding assembly comprising an arm adapted for movement in a transverse direction of the boiler tube panel;
• and
• an overlay welding head mounted to the arm of the welding assembly and adapted for depositing an overlay weld on the second surface of the boiler tube panel;
• and
• means for straightening the boiler tube panel following deposition of the overlay weld on the second surface of the boiler tube panel, the straightening means comprising:
• a stationary member having a contact surface with a profile that is complementary to the second surface of the boiler tube panel, the stationary member being sized to engage substantially all of the transverse width of the boiler tube panel;
• a ram member having a contact surface with a profile that is complementary to the first surface of the boiler tube panel, the ram member being sized to engage less than the transverse width of the boiler tube panel;
• means for actuating the ram member toward and away from the stationary member in directions normal to the stationary member, the actuating means operating to cause the ram member to move toward the stationary member to press a portion of the boiler tube panel therebetween, and the actuating means operating to cause the ram member to move away from the stationary member to release the boiler tube panel;
• means for moving the ram member in a direction parallel to the stationary member and in the transverse direction of the boiler tube panel;
• and
• means for positioning the boiler tube panel between the ram and stationary members.

A process for depositing an overlay weld on a boiler tube panel comprising a plurality of tubes with adjacent tubes joined together with membranes therebetween, the process comprising the steps of:

• supporting the boiler tube panel and then overlay welding the boiler tube panel, the boiler tube panel being supported on a frame that contacts a first surface of the boiler tube panel, the overlay welding being carried out with at least one overlay welding head supported by a welding carriage traveling along the frame, the overlay welding head depositing an overlay weld on a second surface of the boiler tube panel oppositely disposed from the first surface of the boiler tube panel;
• positioning the boiler tube panel between first and second members, the first member having a contact surface with a profile that is complementary to the first surface of the boiler tube panel, the second member having a contact surface with a profile that is complementary to the second surface of the boiler tube panel;
• straightening the boiler tube panel by moving the first and second members toward each other so that the first surface of the boiler tube panel is contacted with the contact surface of the first member, the second surface of the boiler tube panel is contacted with the second member, and a portion of the boiler tube panel is pressed therebetween;
• and then
• moving the first and second members away from each other to release the boiler tube panel.

A process for depositing an overlay weld on a boiler tube panel comprising a plurality of tubes with adjacent tubes joined together with membranes therebetween, the process comprising the steps of:

• horizontally supporting the boiler tube panel on an elongate frame that contacts a first surface of the boiler tube panel so that an oppositely-disposed second surface of the boiler tube panel faces upward;
• overlay welding the second surface of the boiler tube panel with at least one overlay welding head supported by an arm of a welding carriage, the welding carriage moving the overlay welding head in a longitudinal direction of the boiler tube panel and the arm moving the overlay welding head in a transverse direction of the boiler tube panel;
• positioning the boiler tube panel between ram and stationary members, the ram member having a contact surface with a profile that is complementary to the first surface of the boiler tube panel, the stationary member having a contact surface with a profile that is complementary to the second surface of the boiler tube panel, the ram member being sized to engage less than the transverse width of the boiler tube panel, the stationary member being sized to engage substantially all of the transverse width of the boiler tube panel;
• straightening a first portion of the boiler tube panel by moving the ram member toward the stationary member so that the first surface of the boiler tube panel is contacted with the contact surface of the ram member, the second surface of the boiler tube panel is contacted with the stationary member, and the first portion is pressed therebetween;
• releasing the boiler tube panel by moving the ram member away from the stationary member;
• moving the ram member in a direction parallel to the stationary member and transverse to the boiler tube panel;
• moving the ram member toward the stationary member to press a second portion of the boiler tube panel therebetween;
• and then
• moving the ram member away from the stationary member to release the boiler tube panel.