Method for tube end preparation and milling head therefore

• US 20050053440A1
• Filed: 09/09/2003
• Published: 03/10/2005
• Est. Priority Date: 09/09/2003
• Status: Active Grant

• Current Assignee: Climax Portable Machine Tools, Inc. (CPMT Holdings Corp.)
• Original Assignee: H&S Tool Incorporated (CPMT Holdings Corp.)
• Inventors: Hall, J. Randall
• Granted Patent: US 7,143,673 B2
• Time in Patent Office: Days
• US Class Current: 409/132
• CPC Class Codes: B23B 2210/02 Tool holders having multiple cutting inserts
• CPC Class Codes: B23B 2226/18 Ceramic
• CPC Class Codes: B23B 2260/124 Screws
• CPC Class Codes: B23B 5/162 with an internal clamping device
• CPC Class Codes: B23B 5/168 with guiding devices
• CPC Class Codes: B23C 3/007 Milling end surfaces of nuts or tubes
• CPC Class Codes: Y10T 407/1906 including holder [i.e., head] having seat for inserted tool
• CPC Class Codes: Y10T 407/1936 Apertured tool
• CPC Class Codes: Y10T 407/1946 Face or end mill
• CPC Class Codes: Y10T 407/22 including holder having seat for inserted tool
• CPC Class Codes: Y10T 408/8923 Removable central lead
• CPC Class Codes: Y10T 408/893 Hollow milling Tool
• CPC Class Codes: Y10T 409/303808 including infeeding
• CPC Class Codes: Y10T 409/304144 Means to trim edge
• CPC Class Codes: Y10T 82/16 Severing or cut-off
• CPC Class Codes: Y10T 82/16606 Fluid motor
• CPC Class Codes: Y10T 82/22 Portable lathe for pipe turning

Abstract

Tube ends such as those of boiler tube banks, are prepared utilizing any of various combinations of processes which include a step of micro-diameter tube film removal from a portion of a tube end, including an area below a beveled segment, or segment to be beveled. The micro-diameter film removal step provides the tube with an exposed, clean metal surface which is conducive to a subsequent welding or bonding operation performed on the tube. Preferably, the process is performed with a tube milling tool having interchangeable milling or cutting heads. A specialized milling head is also disclosed and, in one embodiment, is at least used to perform the micro-diameter tube film removal step. Advantageously, the tube film removal milling head also removes a weld overlay on one or both sides of a tube in one embodiment. The tube film removal milling head includes an attached blade having a planar face configuration which enables tube film removal.

Claims

1. A method for preparing a tube end for a welding operation, comprising the steps of:

utilizing a rotary milling tool having a first milling head to remove a predetermined amount of radial thickness from the outer diameter of said tube to a predetermined depth; and

beveling the end of said tube utilizing said rotary milling tool.

2. A method according to claim 1, further including the step of removing a membrane adjacent said tube end, or a weld overlay adjacent said tube end, or a combination thereof to a predetermined depth.

3. A method according to claim 1, further including the step of removing a weld overlay from a front portion or a back portion of said tube, or a combination thereof, with said first milling head to a predetermined depth either simultaneously with or after said tube radial thickness removal step.

4. A method according to claim 1, wherein from about 2% up to about 25% of said tube radial thickness is removed during said tube diameter removal step, and wherein said tube diameter removal step is performed to a depth of from about 0.25 to about 1.5 inches when measured from said tube end.

5. A method according to claim 3, wherein from about 2% up to about 25% of said tube radial thickness is removed during said tube diameter removal step, and wherein said tube diameter removal step is performed to a depth of from about 0.25 to about 1.5 inches when measured from said tube end.

6. A method according to claim 4, wherein up to about 10% of said tube radial thickness is removed, and wherein said depth is from about 0.25 to about 1 inch.

7. A method according to claim 5, wherein up to about 10% of said tube radial thickness is removed, and wherein said depth is from about 0.25 to about 1 inch.

8. A method according to claim 2, wherein said beveling step is performed with a second milling head and said membrane removal is performed with a third milling head.

9. A method according to claim 8, wherein up to about 25% of said tube radial thickness is removed during said tube diameter removal step, and wherein said tube diameter removal step is performed to a depth of from about 0.25 to about 1.5 inches when measured from said tube end.

20. A method according to claim 1, wherein said first milling head has a blade secured to said milling head with a securing element, and wherein said securing element has an end portion which extends a first distance which is less than or equal to a second distance measured from a bottom edge of the securing element to a bottom edge of the blade.

10. A rotary milling head for a rotary milling tool, comprising:

a cylindrical body having an annular recess, said body adapted to be connected to a rotary milling tool;

one or more cutting blades connected to said body by a securing element, each said blade disposed circumferentially around the rotational axis of the milling head, each said blade having a cutting edge defining an annular cutting sweep having an inner radius which is adapted to remove an outer radial thickness from an annular tube in an amount of from about 2% up to about 25% of said annular tube thickness, and an outer radius at least equal to said tube outer diameter.

11. A milling head according to claim 10, wherein said blade has a face surface with a bore extending therethrough through which said securing element connects said blade to said body, said blade having a countersink around said bore capable of receiving at least a portion of a head of said securing element.

12. A milling head according to claim 11, wherein said securing element connects said blade to said body whereby the securing element head portion has an end which is flush mounted or recess mounted in relation to said blade face.

13. A milling head according to claim 11, wherein said securing element connects said blade to said body whereby the securing element has a head portion which extends out from said blade face surface a first distance which is less than or equal to a second distance measured from a lower edge of the securing element head to a lower cutting edge of the blade.

14. A milling head according to claim 12, wherein said blade cutting sweep inner radius is from about 2% to about 15% of said annular tube thickness.

15. A milling head according to claim 13, wherein said blade cutting sweep inner radius is from about 2% to about 15% of said annular tube thickness.

16. A milling head according to claim 12, wherein said blade cutting sweep inner radius is from about 2% to about 10% of said annular tube thickness.

17. A milling head according to claim 13, wherein said blade cutting sweep inner radius is from about 2% to about 10% of said annular tube thickness.

18. A milling head according to claim 14, wherein said first distance is less than about 95% of said second distance.

19. A milling head according to claim 15, wherein said first distance is less than about 90% of said second distance.