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Expansion Joints

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The presentation will include technical terminologies along with sizing of metallic and non-metallic expansion joints which are used in Steel/Cement/Minerals/Power industries.

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Expansion Joints

  1. 1. Expansion Joint by Nivedit Mathur & Manik Deshpande NISH-IN MLD-IN
  2. 2. This presentation consists of:- <ul><li>Introduction. </li></ul><ul><li>Definition and Application. </li></ul><ul><li>Working Principle. </li></ul><ul><li>Metallic versus Non-Metallic types. </li></ul><ul><li>General considerations for calculating expansion values. </li></ul><ul><li>Case wise methodology:- </li></ul><ul><li>I – For Straight Duct. </li></ul><ul><li>II – For Inclined Duct. </li></ul><ul><li>III – For Pre-heater downcomer duct. </li></ul><ul><li>IV – For Duct with connecting equipments. </li></ul><ul><li>V – For Duct subjected to different temperatures. </li></ul><ul><li>VI – For Expansion Joint located nearer to process damper. </li></ul><ul><li>VII – For Duct subjected to transverse/angular expansion. </li></ul><ul><li>Exercises. </li></ul>
  3. 3. Introduction:- The reasons for organizing this presentation are:- <ul><li>To minimize expansion joint problem/failure at project sites. </li></ul><ul><li>To minimize PL5 dependencies on Plant Utilities. </li></ul><ul><li>To establish a common platform interms of understanding expansion joint terminology, calculation, behavior and documentation. </li></ul>
  4. 4. Definition and Application:- Expansion Joint is an flexible connector designed to perform the following four major task:- <ul><li>To allow expansion and contraction of the duct due to temperature changes. </li></ul><ul><li>To provide isolation of a component to minimize the effects of vibration and noise. </li></ul><ul><li>To allow movement of component during process operation. </li></ul><ul><li>To aid in installation or removal of large components and erection tolerances. </li></ul>
  5. 5. Definition and Application: <ul><li>Axial Elongation – Dimensional lengthening of </li></ul><ul><li>the expansion joint along its longitudinal axis. </li></ul><ul><li>Axial Compression – Dimensional shortening of </li></ul><ul><li>the expansion joint along its longitudinal axis. </li></ul><ul><li>Lateral Movement – Relative displacement of the two ends </li></ul><ul><li>of the expansion joint perpendicular to </li></ul><ul><li>its longitudinal axis. </li></ul><ul><li>Angular Movement – Displacement of the longitudinal axis of </li></ul><ul><li>the expansion joint from its initial straight </li></ul><ul><li>line position into a circular arc. </li></ul>
  6. 6. Working Principle:- <ul><li>Non Metallic Type – Works on the basis of fabric as flexible element formed into </li></ul><ul><li>one or maximum two convolution. </li></ul><ul><li>Metallic Type – Works on the basis of thin metallic sheets as flexible element </li></ul><ul><li>formed into multiple convolutions. </li></ul>
  7. 7. Metallic versus Non-Metallic Type: <ul><li>Temperature </li></ul><ul><li>Standard rubber joints have an upper range to 230-deg F. </li></ul><ul><li>Standard metal joints are designed up to 420-deg F to 1800-deg F. </li></ul><ul><li>Movements </li></ul><ul><li>Rubber joints absorbs far greater lateral movements when compared to metal joints </li></ul><ul><li>Similar face to face dimensions. </li></ul><ul><li>Spring Rates – Defined as the total force required to move an expansion joint by one inch in any direction. </li></ul><ul><li>Rubber Joints – Low spring rate. </li></ul><ul><li>Metal Joints – High spring rate. </li></ul><ul><li>Gas Tightness at all temperature </li></ul><ul><li>Rubber Joints – Lower </li></ul><ul><li>Metal Joints - Higher </li></ul>
  8. 8. Basic Consideration:- <ul><li>Temperature for calculation (T) = design - minimum ambient temperature(If not insulated) and Temperature =design (IF insulated). </li></ul><ul><li>Thermal coefficient (a) = 12x10^-6. </li></ul><ul><li>Length(L): </li></ul><ul><li>Length can be calculated from the 1 st fixed support to expansion </li></ul><ul><li>joint center and Expansion joint center to 2 nd Fixed Support. </li></ul><ul><li>No need to consider any margin for values of expansion joint as it is calculated for design temperature. </li></ul>
  9. 9. Basic Consideration:- <ul><li>If movements acts in same direction then the movements value should be subtracted and vice versa... </li></ul><ul><li>For those expansion joints which comes with connecting equipment the movements due to corresponding Connecting equipment also has to be considered. </li></ul><ul><li>1. For Cyclone, Temperature should be skin temperature </li></ul><ul><li>2. For ESP and other Connecting equipment, movements will be specified in the OL drawings. </li></ul><ul><li>3. For mill and cooler as per respective department there will be no movements. </li></ul><ul><li>For tall elevators and chain conveyors expansion values given in the respective OL/ Supplier drgs to be considered </li></ul>Formula:- Increase in length = aTL
  10. 10. Case wise Methodology: <ul><li>I – For Straight Duct. </li></ul>
  11. 11. <ul><li>II – For Inclined Duct. </li></ul>
  12. 12. <ul><li>III – For Pre-heater downcomer duct. </li></ul>Two different values of temperature must be considered for calculation For Cyclone Temperature should be skin temperature III – For Pre-heater downcomer duct. Total axial movement is 35.145+12.48=47.625~50mm
  13. 13. <ul><li>IV – For Duct with connecting equipments. </li></ul>Movement due to connecting equipment must be taken in to consideration. Resultant movement
  14. 14. <ul><li>V – For Duct subjected to different temperatures. </li></ul>Two different temperature condition on the same duct. Two different temperature condition on the same duct.
  15. 15. <ul><li>VI – For Expansion Joint located nearer to process damper. </li></ul>During shut off condition the movements due to duct 85-10 will alone exist and movements due to duct 85-3 will not act So maximum lateral movements is considered and axial movements due to both duct considering working condition. .
  16. 16. <ul><li>VII – For Duct subjected to transverse expansion. </li></ul>As Axial movement for this expansion joint act in the same direction the relative value Should be considered . . As both the lateral values act in two different axis the resultant is taken (√13.152+21.482) Two different temperature condition on the same duct. Two different temperature condition on the same duct.
  17. 17. <ul><li>VIII – Special Case. </li></ul>In cases like this where the slide support is placed you have to check the moment acting on the fixed support. Resultant movement
  18. 18. <ul><li>Exercise </li></ul>
  19. 19. <ul><li>Thank you. </li></ul>

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