Podcast
Questions and Answers
EASY What is a common occurrence in boiler tubes due to various operating conditions?
EASY What is a common occurrence in boiler tubes due to various operating conditions?
- Tube maintenance
- Tube failure (correct)
- Tube repair
- Tube success
What can cause overheating in boiler tubes?
What can cause overheating in boiler tubes?
- Low water fuel cut-off
- Proper water treatment
- Over firing (correct)
- Good water circulation
What is a sign of slight overheating in boiler tubes?
What is a sign of slight overheating in boiler tubes?
- Tube rupture
- Tube collapse
- Tube corrosion
- Tube drooping (correct)
What can cause tube walls to weaken?
What can cause tube walls to weaken?
What can cause tube ends to crack?
What can cause tube ends to crack?
What is a repair in the context of boilers?
What is a repair in the context of boilers?
What must be done when a tube wall is perforated or ruptured?
What must be done when a tube wall is perforated or ruptured?
What is required for both repairs and alterations of boilers?
What is required for both repairs and alterations of boilers?
What is the purpose of plugging a firetube?
What is the purpose of plugging a firetube?
What is the length of the steel plugs needed to plug a firetube?
What is the length of the steel plugs needed to plug a firetube?
What is the purpose of the 16 mm diameter steel rod?
What is the purpose of the 16 mm diameter steel rod?
What is the term used to describe a firetube with minor leakage at its seat?
What is the term used to describe a firetube with minor leakage at its seat?
What tool is used to re-expand a weeping firetube?
What tool is used to re-expand a weeping firetube?
What is the purpose of applying a special paste-style lubricant to the tube expander?
What is the purpose of applying a special paste-style lubricant to the tube expander?
What should be done to the tube end after re-expanding it?
What should be done to the tube end after re-expanding it?
Why should the tube end not be over-expanded?
Why should the tube end not be over-expanded?
What is the final step in the procedure for re-expanding tubes?
What is the final step in the procedure for re-expanding tubes?
What is the purpose of seal welding the tube end?
What is the purpose of seal welding the tube end?
Who should replace the boiler tubes?
Who should replace the boiler tubes?
What should be done before replacing a defective tube?
What should be done before replacing a defective tube?
What is required for boiler pressure vessel repairs in all Canadian jurisdictions?
What is required for boiler pressure vessel repairs in all Canadian jurisdictions?
What is the purpose of annealing the tube ends?
What is the purpose of annealing the tube ends?
What is used to check the tightness of the tube ends?
What is used to check the tightness of the tube ends?
Who can perform welding on a pressure part of a boiler?
Who can perform welding on a pressure part of a boiler?
What should be done to the tube sheets after removing the tube?
What should be done to the tube sheets after removing the tube?
Why should the tube ends be expanded lightly again after beading?
Why should the tube ends be expanded lightly again after beading?
What tool is used to bead the tube ends?
What tool is used to bead the tube ends?
What is the first step in removing a defective tube?
What is the first step in removing a defective tube?
MEDIUM What is the purpose of plugging a firetube?
MEDIUM What is the purpose of plugging a firetube?
What is the purpose of a three-roller expander?
What is the purpose of a three-roller expander?
What should be done to the tube end after re-expanding it?
What should be done to the tube end after re-expanding it?
Why should the tube end not be over-expanded?
Why should the tube end not be over-expanded?
What is the final step in the procedure for re-expanding tubes?
What is the final step in the procedure for re-expanding tubes?
What is the term used to describe a firetube with minor leakage at its seat?
What is the term used to describe a firetube with minor leakage at its seat?
What is the purpose of applying a special paste-style lubricant to the tube expander?
What is the purpose of applying a special paste-style lubricant to the tube expander?
What tool is used to bead the tube ends?
What tool is used to bead the tube ends?
Why should the tube ends be expanded lightly again after beading?
Why should the tube ends be expanded lightly again after beading?
What is the purpose of seal welding the tube end?
What is the purpose of seal welding the tube end?
What is the primary reason for corrosion on the waterside of boiler tubes?
What is the primary reason for corrosion on the waterside of boiler tubes?
What is the consequence of severe overheating in boiler tubes?
What is the consequence of severe overheating in boiler tubes?
What is the definition of a repair in the context of boilers?
What is the definition of a repair in the context of boilers?
What is the consequence of uneven expansion in boiler tubes?
What is the consequence of uneven expansion in boiler tubes?
What is the consequence of heavy scale formation on boiler tubes?
What is the consequence of heavy scale formation on boiler tubes?
What must be done when a tube wall is perforated or ruptured?
What must be done when a tube wall is perforated or ruptured?
What is required for all boiler repairs and alterations?
What is required for all boiler repairs and alterations?
What can cause a tube to collapse completely?
What can cause a tube to collapse completely?
Who should be consulted and approved before making repairs affecting the pressure part of a boiler?
Who should be consulted and approved before making repairs affecting the pressure part of a boiler?
What is the purpose of annealing the tube ends?
What is the purpose of annealing the tube ends?
What is required for boiler pressure vessel repairs in all Canadian jurisdictions?
What is required for boiler pressure vessel repairs in all Canadian jurisdictions?
What tool is used to bead the tube ends?
What tool is used to bead the tube ends?
Why should the tube ends be expanded lightly again after beading?
Why should the tube ends be expanded lightly again after beading?
Who can perform welding on a pressure part of a boiler?
Who can perform welding on a pressure part of a boiler?
What is the purpose of seal welding the tube end?
What is the purpose of seal welding the tube end?
What should be done to the tube sheets after removing the tube?
What should be done to the tube sheets after removing the tube?
What is the first step in removing a defective tube?
What is the first step in removing a defective tube?
What is used to check the tightness of the tube ends?
What is used to check the tightness of the tube ends?
HARD What is the primary purpose of submitting a jurisdictional “Repair and Alteration” approval form for boiler pressure vessel repairs?
HARD What is the primary purpose of submitting a jurisdictional “Repair and Alteration” approval form for boiler pressure vessel repairs?
What is the primary reason for consulting an authorized inspector before making repairs affecting the pressure part of a boiler?
What is the primary reason for consulting an authorized inspector before making repairs affecting the pressure part of a boiler?
What is the consequence of not annealing the tube ends before replacing a defective tube?
What is the consequence of not annealing the tube ends before replacing a defective tube?
What is the purpose of lightly expanding the tube ends again after beading?
What is the purpose of lightly expanding the tube ends again after beading?
What is the minimum requirement for a repair shop to replace boiler tubes in some jurisdictions?
What is the minimum requirement for a repair shop to replace boiler tubes in some jurisdictions?
What is the purpose of using emery cloth to clean the tube sheets after removing a defective tube?
What is the purpose of using emery cloth to clean the tube sheets after removing a defective tube?
What is the primary purpose of using a power impact hammer to drive the beading tool?
What is the primary purpose of using a power impact hammer to drive the beading tool?
What is the consequence of not consulting an authorized inspector before making repairs affecting the pressure part of a boiler?
What is the consequence of not consulting an authorized inspector before making repairs affecting the pressure part of a boiler?
What is the primary purpose of using a round nosed chisel to cut grooves in the tube ends?
What is the primary purpose of using a round nosed chisel to cut grooves in the tube ends?
What is the primary reason for using a specific procedure to replace a defective tube?
What is the primary reason for using a specific procedure to replace a defective tube?
What is the primary mechanism by which corrosive and scale-forming waterborne constituents contribute to tube failure?
What is the primary mechanism by which corrosive and scale-forming waterborne constituents contribute to tube failure?
What is the consequence of a tube failure due to severe overheating?
What is the consequence of a tube failure due to severe overheating?
What is the key distinction between a repair and an alteration in the context of boiler maintenance?
What is the key distinction between a repair and an alteration in the context of boiler maintenance?
What is the primary cause of thermal shock in boiler tubes?
What is the primary cause of thermal shock in boiler tubes?
What is the consequence of caustic embrittlement in boiler tubes?
What is the consequence of caustic embrittlement in boiler tubes?
What is the purpose of approving repairs and alterations by the authority with jurisdiction?
What is the purpose of approving repairs and alterations by the authority with jurisdiction?
What is the consequence of buckling stress on boiler tubes?
What is the consequence of buckling stress on boiler tubes?
What is the primary reason for plugging a defective firetube?
What is the primary reason for plugging a defective firetube?
What is the primary purpose of using a tapered tube expander mandrel in a three-roller expander?
What is the primary purpose of using a tapered tube expander mandrel in a three-roller expander?
What is the consequence of not applying a special paste-style lubricant to the tube expander?
What is the consequence of not applying a special paste-style lubricant to the tube expander?
What is the purpose of beading the tube end after re-expanding it?
What is the purpose of beading the tube end after re-expanding it?
What is the advantage of using a three-roller expander to repair a weeping firetube?
What is the advantage of using a three-roller expander to repair a weeping firetube?
What is the purpose of performing a hydrostatic test after re-expanding a tube?
What is the purpose of performing a hydrostatic test after re-expanding a tube?
What is the consequence of over-expanding a tube end?
What is the consequence of over-expanding a tube end?
What is the purpose of using a 16 mm diameter steel rod when plugging a firetube?
What is the purpose of using a 16 mm diameter steel rod when plugging a firetube?
What is the primary purpose of seal welding the tube end?
What is the primary purpose of seal welding the tube end?
What is the consequence of not re-beading the tube end after re-expanding it?
What is the consequence of not re-beading the tube end after re-expanding it?
What is the purpose of using a grommet of high-temperature rope when plugging a firetube?
What is the purpose of using a grommet of high-temperature rope when plugging a firetube?
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Study Notes
Boiler Tube Failures
- Boiler tubes operate under harsh conditions, experiencing external pressure, buckling stress, tensile stress, corrosive and scale-forming waterborne constituents, and high temperatures.
- Tube failures can occur due to:
- Overheating caused by overfiring, poor water circulation, heavy scale formation, or failure of the low water fuel cut-off.
- Corrosion weakening tube walls, leading to leakage or total collapse.
- Tube ends cracking due to uneven expansion, thermal shock, or caustic embrittlement.
Repairing Defective Firetubes
- A repair is defined as the work necessary to restore a boiler or pressure vessel to a safe and satisfactory operating condition, without deviating from the original design.
- Repairs and alterations are subject to approval by the authority with jurisdiction.
- Plugging a defective firetube can be done temporarily to allow boiler operation to resume until a proper repair can be done.
- To plug a firetube, two steel plugs with a specific taper are needed, along with a steel rod and a high-temperature rope grommet.
Repairing a Weeping Firetube
- A weeping firetube can be repaired by re-expanding the tube end using a three-roller expander.
- The expander is used to attach tubes to tube sheets in firetube boilers and to drums of watertube boilers.
- The procedure involves cleaning the tube ends, coating the expander with lubricant, and inserting the expander to apply outward force against the tube wall.
Removal and Replacement of Defective Firetubes
- If re-expanding the tube does not stop the leak, it will need to be replaced.
- An experienced boilermaker should replace the tube, following approved procedures and obtaining necessary jurisdictional approval.
- The boiler should be taken out of service, cooled, drained, and opened up before replacement.
- Replacement involves cutting off the bead, cutting grooves, breaking away the tube ends, and removing the tube from the boiler.
- The new tube should be annealed, cleaned, and polished before installation, and the tube ends should be expanded and beaded.
Boiler Tube Failures
- Boiler tubes operate under harsh conditions, experiencing external pressure, buckling stress, tensile stress, corrosive and scale-forming waterborne constituents, and high temperatures.
- Tube failures can occur due to:
- Overheating caused by overfiring, poor water circulation, heavy scale formation, or failure of the low water fuel cut-off.
- Corrosion weakening tube walls, leading to leakage or total collapse.
- Tube ends cracking due to uneven expansion, thermal shock, or caustic embrittlement.
Repairing Defective Firetubes
- A repair is defined as the work necessary to restore a boiler or pressure vessel to a safe and satisfactory operating condition, without deviating from the original design.
- Repairs and alterations are subject to approval by the authority with jurisdiction.
- Plugging a defective firetube can be done temporarily to allow boiler operation to resume until a proper repair can be done.
- To plug a firetube, two steel plugs with a specific taper are needed, along with a steel rod and a high-temperature rope grommet.
Repairing a Weeping Firetube
- A weeping firetube can be repaired by re-expanding the tube end using a three-roller expander.
- The expander is used to attach tubes to tube sheets in firetube boilers and to drums of watertube boilers.
- The procedure involves cleaning the tube ends, coating the expander with lubricant, and inserting the expander to apply outward force against the tube wall.
Removal and Replacement of Defective Firetubes
- If re-expanding the tube does not stop the leak, it will need to be replaced.
- An experienced boilermaker should replace the tube, following approved procedures and obtaining necessary jurisdictional approval.
- The boiler should be taken out of service, cooled, drained, and opened up before replacement.
- Replacement involves cutting off the bead, cutting grooves, breaking away the tube ends, and removing the tube from the boiler.
- The new tube should be annealed, cleaned, and polished before installation, and the tube ends should be expanded and beaded.
Boiler Tube Failures
- Boiler tubes operate under harsh conditions, experiencing external pressure, buckling stress, tensile stress, corrosive and scale-forming waterborne constituents, and high temperatures.
- Tube failures can occur due to:
- Overheating caused by overfiring, poor water circulation, heavy scale formation, or failure of the low water fuel cut-off.
- Corrosion weakening tube walls, leading to leakage or total collapse.
- Tube ends cracking due to uneven expansion, thermal shock, or caustic embrittlement.
Repairing Defective Firetubes
- A repair is defined as the work necessary to restore a boiler or pressure vessel to a safe and satisfactory operating condition, without deviating from the original design.
- Repairs and alterations are subject to approval by the authority with jurisdiction.
- Plugging a defective firetube can be done temporarily to allow boiler operation to resume until a proper repair can be done.
- To plug a firetube, two steel plugs with a specific taper are needed, along with a steel rod and a high-temperature rope grommet.
Repairing a Weeping Firetube
- A weeping firetube can be repaired by re-expanding the tube end using a three-roller expander.
- The expander is used to attach tubes to tube sheets in firetube boilers and to drums of watertube boilers.
- The procedure involves cleaning the tube ends, coating the expander with lubricant, and inserting the expander to apply outward force against the tube wall.
Removal and Replacement of Defective Firetubes
- If re-expanding the tube does not stop the leak, it will need to be replaced.
- An experienced boilermaker should replace the tube, following approved procedures and obtaining necessary jurisdictional approval.
- The boiler should be taken out of service, cooled, drained, and opened up before replacement.
- Replacement involves cutting off the bead, cutting grooves, breaking away the tube ends, and removing the tube from the boiler.
- The new tube should be annealed, cleaned, and polished before installation, and the tube ends should be expanded and beaded.
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