1 / 16

American Power Systems Dan Bina Hollaender Enterprises, Inc. Roger Adelman

Insta-Plug ™ New low-pressure Feedwater heater and condenser tube plug Not to leak or fall out for the life of the exchanger. American Power Systems Dan Bina Hollaender Enterprises, Inc. Roger Adelman. Plugging tubes: A problem with many solutions. Metallurgical Plugs

halee-rocha
Download Presentation

American Power Systems Dan Bina Hollaender Enterprises, Inc. Roger Adelman

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Insta-Plug™New low-pressure Feedwater heater and condenser tube plug Not to leak or fall out for the life of the exchanger American Power Systems Dan Bina Hollaender Enterprises, Inc. Roger Adelman

  2. Plugging tubes: A problem with many solutions • Metallurgical Plugs Metallurgical bonding mechanisms: • Welded, brazed, soldered • Explosive (kinetic) • Mechanical Plugs Friction/interference mechanisms: • Tapered cylinders • Tapered cylinder in mating sleeve • Taper around a cylinder (Screws/Compressors)

  3. Mechanical Plugs • Primary Advantages: • Quick to install • Simple to install • Relatively low cost • Effective for lower pressures • Primary Disadvantages: • Failure, particularly with cycling

  4. Why Plugs Fail (1)Forces on a stuck mechanical plug N1 Ff1 = μN1 Alternative Blowout Blowout 2θ N2 Ff = μN2

  5. Why Plugs Fail (2)Friction and normal force competition N1 Ff1 = μN1 Alternative Blowout Blowout 2θ N2 Ff = μN2

  6. Why Plugs Fail (3)Friction and normal force competition N1 N1 Ff1 = μN1 Ff1 = μN1 θ θ 1. As installed 2. Possible In use

  7. Why Plugs Fail (4)Friction loses the competition Ny N Ff = μN Ffy Nx Ffx θ Nx >Ffx , even the slightest amount and plug slips

  8. Why Plugs Fail (4)How can that happen? • Differential behavior of tube and plug • Changes in coefficient of friction • Mechanical dynamics • Infiltration of intermediate material • Other (micro cracking, etc.) IT IS A FAIL “UNSAFE” CONDITION: Once it begins it tends to continue to loosen

  9. A different mechanical approach:InstaPlug™

  10. InstaPlug™A non-wedge based plug unique one-piece shape + a material with very special properties

  11. NiTiNol or “Memory Metal” • Nickel/Titanium alloy • Exists in two allotropic forms (atomic structures) • Martensite (at lower temperatures) • Austenite (at higher temperatures) • Special processing gives two important properties • Ability to “remember” a first shape after being in second • Superelasticity – almost six times “normal” metals • Inert enough to be widely used in medical implants • Retains large elastic energy when press-fit

  12. Simple positive process (1) Create the plug and shrink it Heat treatment As machined d+~0.004” Reduced diameter for installation

  13. Simple positive process (2) Install into well prepared tube/tubesheet • Place in clean tube end • Heat to restore “memorized” interference fit

  14. Insta-Plug common sizes

  15. Engineering and Design • NOT the simple analysis used for exposition here • Sophisticated Finite Element Analysis for • Deflection • Force • Stress/strain distribution • Thermal analysis

  16. Conclusion • We believe that we now have cost effective, and reliable means in the Insta-Plug™ that will: • not fail in service regardless of the cycling conditions • provide for installation that is fast, safe and simple • be cost competitive with other mechanical plugs • account for real world service demands e.g. thermal cycling • We intend that Insta-Plug™, like our experience with explosive welded plugs for high pressure feedwater heaters, will “last the lifetime” of the heat exchanger.

More Related