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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?

  • Low water fuel cut-off
  • Proper water treatment
  • Over firing (correct)
  • Good water circulation

    • 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?

    <p>Corrosion</p> Signup and view all the answers

    What can cause tube ends to crack?

    <p>Uneven expansion</p> Signup and view all the answers

    What is a repair in the context of boilers?

    <p>Work necessary to restore a boiler to its original design</p> Signup and view all the answers

    What must be done when a tube wall is perforated or ruptured?

    <p>The tube must be replaced</p> Signup and view all the answers

    What is required for both repairs and alterations of boilers?

    <p>Approval of the authority with jurisdiction</p> Signup and view all the answers

    What is the purpose of plugging a firetube?

    <p>To allow the boiler to operate temporarily until a proper repair can be done</p> Signup and view all the answers

    What is the length of the steel plugs needed to plug a firetube?

    <p>75 mm</p> Signup and view all the answers

    What is the purpose of the 16 mm diameter steel rod?

    <p>To hold the plugs in place</p> Signup and view all the answers

    What is the term used to describe a firetube with minor leakage at its seat?

    <p>Weeping firetube</p> Signup and view all the answers

    What tool is used to re-expand a weeping firetube?

    <p>Three-roller expander</p> Signup and view all the answers

    What is the purpose of applying a special paste-style lubricant to the tube expander?

    <p>To reduce friction between the tube and the expander</p> Signup and view all the answers

    What should be done to the tube end after re-expanding it?

    <p>Re-bead the tube end</p> Signup and view all the answers

    Why should the tube end not be over-expanded?

    <p>It will weaken the tube end</p> Signup and view all the answers

    What is the final step in the procedure for re-expanding tubes?

    <p>Apply a hydrostatic test</p> Signup and view all the answers

    What is the purpose of seal welding the tube end?

    <p>To strengthen the tube end</p> Signup and view all the answers

    Who should replace the boiler tubes?

    <p>An experienced boilermaker</p> Signup and view all the answers

    What should be done before replacing a defective tube?

    <p>Cool, drain, and open up the boiler</p> Signup and view all the answers

    What is required for boiler pressure vessel repairs in all Canadian jurisdictions?

    <p>Prior approval and a Repair and Alteration form</p> Signup and view all the answers

    What is the purpose of annealing the tube ends?

    <p>To soften the tube ends</p> Signup and view all the answers

    What is used to check the tightness of the tube ends?

    <p>A hydrostatic test</p> Signup and view all the answers

    Who can perform welding on a pressure part of a boiler?

    <p>A holder of a Pressure Welder's Certificate and a valid Performance Qualification Card</p> Signup and view all the answers

    What should be done to the tube sheets after removing the tube?

    <p>Clean them with emery cloth</p> Signup and view all the answers

    Why should the tube ends be expanded lightly again after beading?

    <p>Because the beading process may have loosened them</p> Signup and view all the answers

    What tool is used to bead the tube ends?

    <p>A beading tool</p> Signup and view all the answers

    What is the first step in removing a defective tube?

    <p>Cut off the bead at each end of the tube</p> Signup and view all the answers

    MEDIUM What is the purpose of plugging a firetube?

    <p>To temporarily resume boiler operation until a boiler maker is available</p> Signup and view all the answers

    What is the purpose of a three-roller expander?

    <p>To expand and flare tube ends in firetube boilers</p> Signup and view all the answers

    What should be done to the tube end after re-expanding it?

    <p>Re-bead the tube end</p> Signup and view all the answers

    Why should the tube end not be over-expanded?

    <p>It may weaken the tube end</p> Signup and view all the answers

    What is the final step in the procedure for re-expanding tubes?

    <p>Apply a hydrostatic test</p> Signup and view all the answers

    What is the term used to describe a firetube with minor leakage at its seat?

    <p>Weeping firetube</p> Signup and view all the answers

    What is the purpose of applying a special paste-style lubricant to the tube expander?

    <p>To facilitate expansion</p> Signup and view all the answers

    What tool is used to bead the tube ends?

    <p>Beading tool</p> Signup and view all the answers

    Why should the tube ends be expanded lightly again after beading?

    <p>To ensure a tight seal</p> Signup and view all the answers

    What is the purpose of seal welding the tube end?

    <p>To add additional strength</p> Signup and view all the answers

    What is the primary reason for corrosion on the waterside of boiler tubes?

    <p>Poor water treatment</p> Signup and view all the answers

    What is the consequence of severe overheating in boiler tubes?

    <p>The tubes may collapse completely, leading to a serious pressure vessel explosion</p> Signup and view all the answers

    What is the definition of a repair in the context of boilers?

    <p>The work necessary to restore a boiler or pressure vessel to a safe and satisfactory operating condition, without deviating from the original design</p> Signup and view all the answers

    What is the consequence of uneven expansion in boiler tubes?

    <p>The tube ends may crack</p> Signup and view all the answers

    What is the consequence of heavy scale formation on boiler tubes?

    <p>The tube may become more prone to overheating</p> Signup and view all the answers

    What must be done when a tube wall is perforated or ruptured?

    <p>The tube must be replaced</p> Signup and view all the answers

    What is required for all boiler repairs and alterations?

    <p>The approval of the authority with jurisdiction</p> Signup and view all the answers

    What can cause a tube to collapse completely?

    <p>All of the above</p> Signup and view all the answers

    Who should be consulted and approved before making repairs affecting the pressure part of a boiler?

    <p>An authorized inspector</p> Signup and view all the answers

    What is the purpose of annealing the tube ends?

    <p>To soften the tube ends to prevent cracking during expansion</p> Signup and view all the answers

    What is required for boiler pressure vessel repairs in all Canadian jurisdictions?

    <p>Submission and approval of a jurisdictional 'Repair and Alteration' approval form</p> Signup and view all the answers

    What tool is used to bead the tube ends?

    <p>Beading tool</p> Signup and view all the answers

    Why should the tube ends be expanded lightly again after beading?

    <p>To ensure the tube ends are securely fastened</p> Signup and view all the answers

    Who can perform welding on a pressure part of a boiler?

    <p>A holder of a Pressure Welder's Certificate and a valid Performance Qualification Card</p> Signup and view all the answers

    What is the purpose of seal welding the tube end?

    <p>To ensure the tube end is securely fastened</p> Signup and view all the answers

    What should be done to the tube sheets after removing the tube?

    <p>Clean off any roughness with emery cloth</p> Signup and view all the answers

    What is the first step in removing a defective tube?

    <p>Cut off the bead at each end of the tube</p> Signup and view all the answers

    What is used to check the tightness of the tube ends?

    <p>Hydrostatic test</p> Signup and view all the answers

    HARD What is the primary purpose of submitting a jurisdictional “Repair and Alteration” approval form for boiler pressure vessel repairs?

    <p>To ensure compliance with local regulations and obtain approval for the repair procedure</p> Signup and view all the answers

    What is the primary reason for consulting an authorized inspector before making repairs affecting the pressure part of a boiler?

    <p>To ensure compliance with local regulations and obtain approval for the repair procedure</p> Signup and view all the answers

    What is the consequence of not annealing the tube ends before replacing a defective tube?

    <p>The tube may crack during expansion</p> Signup and view all the answers

    What is the purpose of lightly expanding the tube ends again after beading?

    <p>To prevent the tube from becoming loose over time</p> Signup and view all the answers

    What is the minimum requirement for a repair shop to replace boiler tubes in some jurisdictions?

    <p>Approved Quality Assurance program</p> Signup and view all the answers

    What is the purpose of using emery cloth to clean the tube sheets after removing a defective tube?

    <p>To smooth out any rough surfaces on the tube sheet</p> Signup and view all the answers

    What is the primary purpose of using a power impact hammer to drive the beading tool?

    <p>To apply additional force to the beading tool</p> Signup and view all the answers

    What is the consequence of not consulting an authorized inspector before making repairs affecting the pressure part of a boiler?

    <p>It may be unlawful to perform the repair</p> Signup and view all the answers

    What is the primary purpose of using a round nosed chisel to cut grooves in the tube ends?

    <p>To create a surface for the beading tool</p> Signup and view all the answers

    What is the primary reason for using a specific procedure to replace a defective tube?

    <p>To ensure the repair is done correctly and safely</p> Signup and view all the answers

    What is the primary mechanism by which corrosive and scale-forming waterborne constituents contribute to tube failure?

    <p>By weakening tube walls, leading to leakage or collapse</p> Signup and view all the answers

    What is the consequence of a tube failure due to severe overheating?

    <p>The tube will collapse, causing a serious pressure vessel explosion</p> Signup and view all the answers

    What is the key distinction between a repair and an alteration in the context of boiler maintenance?

    <p>A repair involves restoring the original design, while an alteration involves deviating from the original design</p> Signup and view all the answers

    What is the primary cause of thermal shock in boiler tubes?

    <p>Uneven expansion due to poor water circulation</p> Signup and view all the answers

    What is the consequence of caustic embrittlement in boiler tubes?

    <p>Tube ends may crack due to uneven expansion</p> Signup and view all the answers

    What is the purpose of approving repairs and alterations by the authority with jurisdiction?

    <p>To guarantee that the boiler is safe and efficient after the repair or alteration</p> Signup and view all the answers

    What is the consequence of buckling stress on boiler tubes?

    <p>Tubes may collapse, causing a serious pressure vessel explosion</p> Signup and view all the answers

    What is the primary reason for plugging a defective firetube?

    <p>To prevent further damage to the boiler and ensure safe operation</p> Signup and view all the answers

    What is the primary purpose of using a tapered tube expander mandrel in a three-roller expander?

    <p>To apply outward force against the tube wall</p> Signup and view all the answers

    What is the consequence of not applying a special paste-style lubricant to the tube expander?

    <p>The tube expander will not rotate properly</p> Signup and view all the answers

    What is the purpose of beading the tube end after re-expanding it?

    <p>To provide a secure seal against the tube sheet</p> Signup and view all the answers

    What is the advantage of using a three-roller expander to repair a weeping firetube?

    <p>It re-expands the tube end to its original diameter</p> Signup and view all the answers

    What is the purpose of performing a hydrostatic test after re-expanding a tube?

    <p>To check the effectiveness of the repair</p> Signup and view all the answers

    What is the consequence of over-expanding a tube end?

    <p>The tube end will be weakened</p> Signup and view all the answers

    What is the purpose of using a 16 mm diameter steel rod when plugging a firetube?

    <p>To connect the two steel plugs together</p> Signup and view all the answers

    What is the primary purpose of seal welding the tube end?

    <p>To prevent bending loads or sudden temperature changes</p> Signup and view all the answers

    What is the consequence of not re-beading the tube end after re-expanding it?

    <p>The tube end will not be securely sealed</p> Signup and view all the answers

    What is the purpose of using a grommet of high-temperature rope when plugging a firetube?

    <p>To seal the tube ends watertight</p> Signup and view all the answers

    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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    Description

    This quiz covers the reasons behind boiler tube failures, including overheating, poor water circulation, and more. Learn about the common causes of tube failure and how to prevent them.

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