Design-Engg-mfg-testing of Bellows Expansion Joints_442013144211

IGP GroupDesign, Engineering, Manufacturing & Testing of

Bellows type Expansion Joints

LONESTAR INDUSTRIESChennai, India

By R.V. RAMACHANDRAN


Metal Bellows Expansion Joints are used in several applications / end uses. They can be designed for various combinations of operating conditions,

Pressure as high as 200 kg/cm2 (g)

Temperature as high as 1450o C

Metal Bellows can be manufactured from any formable material, the most popular material in modern day uses are,

Austenitic Stainless Steels (304, 304L, 304H, 316, 316L, 316H, 316Ti, 321), Duplex & Super Duplex Stainless Steels, Super Austenitic Stainless Steels (AL 6XN, 254 SMO, 904L), High Nickel Alloys (230, C276, 400, 600, 601, 625, 800, 800H, 825), Titanium & Titanium alloys,

The End connection Pipes shall be in the above grades in addition to Carbon Steel , Low Alloy Steel and combination of any of these,,

Bellows type Metal Expansion Joints







INPUT FOR DESIGN

By Customer:

Type of Expansion JointSize, Nominal Pipe Size / OD of Connecting Pipe x ThicknessType of End Connection – Flanged / Welded End (Flange Dimensions in case of Flanged End)Temperature – Maximum Operating / DesignPressure – Maximum Operating / DesignMovements – Axial, Lateral & Angular (individually or combination of any of these)Material of Construction – Bellows / Connecting Pipe, compatible for process mediumFlow Medium – Liquid / Gas / Solid / Semisolid / CompositionFlow VelocityOverall Length / Maximum Space AvailableExternal Loads – Wind / Seismic / Dead Weight Installation Position – Horizontal / Vertical / InclinedInsulation DetailsCode Compliance

By Manufacturer:

Bellows Design:

Bellows IDConvolution Depth (Height)Convolution PitchThickness of Bellows ConvolutionsNumber of Plies of Bellows ConvolutionsType of Bellows – Unreinforced (Single / Universal) & Reinforced (Single / Universal)Centre Distance between the Bellows (in case of Universal)



Pitch

Depth



Codes & Standards, Pre-dominantly Followed,

EJMA (Expansion Joint Manufacturers Association)

ASME Sec VIII Div. 1 Appendix 26 (for Bellows Expansion Joints for Shell & Tube Heat Exchangers)

ASME B31.3 (Process Piping Code)

ASME B31.1 (Power Piping Code)



Acceptable Design:

Pressure Stresses within the specified limit, Reference: Codes / Standards

Bellows Tangent Circumferential Membrane Stress ‘’ S1’’ due to pressure ≤ Cwb * Allowable Stress of Bellows Material at specified temperature

Cwb, Bellows longitudinal weld joint efficiency, 1 if 100% radio graphed, 0.8 if not,

Collar Circumferential Membrane Stress ‘’’S’1’’ due to pressure ≤ Cwc * Allowable Stress of Bellows Material at specified temperature

Cwc, Collar longitudinal weld joint efficiency, 1 if 100% radio graphed, 0.8 if not,

Bellows Circumferential Membrane Stress ‘’S2’’ due to pressure ≤ Cwb * Allowable Stress of Bellows Material at specified temperature

Cwb, Bellows longitudinal weld joint efficiency, 1 if 100% radio graphed, 0.8 if not,

Bellows Meridional Membrane Stress ‘’S3’’ due to pressure / Bellows Meridional Bending Stress ‘’S4’’ due to pressure, S3 + S4 ≤ Cm* Allowable Stress of Bellows Material at specified temperature

Cm – 3, for Bellows in as formed conditionCm – 1.5, for Bellows subjected to annealing, after forming

Limiting Design Pressure:

Bellows LIMITING DESIGN PRESSURE (LDP) based on Column Instability and / or Inplane Instability,

should be equal or higher than the specified Pressure, if the Operating / Design Temperature is above 200o C

should be 1.5 times higher than the specified Pressure, if the Operating / Design Temperature is less than 200o C



Spring Rate: The spring rate (Stiffness) of the Bellows shall be within the specified limit by the Customer

Permissible Life: The permissible Life of Bellows shall be equal or above the specified Design Life by the Customer

Expansion Joint under External Pressure / Vacuum:

Cylindrical End Connection & Centre Spool (Universal Bellows) - Evaluated as per ASME Sec VIII Div. 1

Bellows - If the moment of inertia of Bellows is higher than the moment of inertia of the pipe (that theBellows replaces), then the Bellows is considered to be equivalent to the pipe for the elastic buckling analysis

I 1-1 I 1-1

I 2-2



Design of other Hardware:

Limit Rods / Tie Rods:- Evaluated for Tensile Load and for Compressive Load

Hinge Pins:- Evaluated for Shear / Bending Load

Hinge Plates:- Evaluated for longitudinally applied Tensile & Compressive loads- Shear & Bearing forces at hinge pin hole- Bending load resulting from Wind & Torsion

Support Brackets / Support Rings:- Evaluated for Bending Load under both Positive Pressure and Vacuum

Lugs / Lug Pads / Stiffeners:- Evaluated for Shear Load

Load for Design of Hardware:Bellows full Pressure ThrustSpring ForcesAdditional Load – Unsupported weight of connecting pipe, Weight of contained fluid under operating / testing conditions (specified by the customer)Other Loads – Wind & Seismic (specified by the customer)Torsion about the longitudinal axis of the Expansion Joint



Heat treatment of Bellows:

Pre-dominantly, the Bellows after forming is not subjected to any form heat treatment, since

the post forming heat treatment of Bellows is in no way beneficial in enhancing the life of Bellows,

the enhanced strength property of the material due to cold working has been included in evaluating stress due to pressure,

Bellows Meridional Membrane Stress ‘’S3’’ due to pressure / Bellows Meridional Bending Stress ‘’S4’’ due to pressure, S3 + S4 ≤ Cm* Allowable Stress of Bellows Material at specifiedtemperature

Cm – 3, for Bellows in as formed conditionCm – 1.5, for Bellows subjected to annealing, after forming

Heat treatment of Bellows after forming can be considered in case if the Expansion Joint is meant for sour service, where the evaluation of Bellows Pressure Stresses is different

UNLESS SPECIFIED, THE HEAT TREATMENT OF BELLOWS AFTER FORMING SHALL BE AS PER EITHER ASME CODE OR MATERIAL MANUFACTURER’S RECOMMENDATIONS



Internal Sleeve:

Internal Sleeves are required in cases,

the higher flow velocities could induce resonant vibration,

internal sleeves must be provided, in case if the flow velocity exceeds 8 m/sec in case of liquid flowmedium and 20 m/sec in case of gaseous flow medium

it is necessary to minimize the friction losses and to ensure smooth flow,

the flow medium is abrasive in nature leading to erosion of thin gauged Bellows,

the flow medium of higher temperature, to facilitate an annular gap, this annular gap is insulatedadequately to reduce the temperature at outer Bellows skin,

To minimize the flow induced vibration, the thickness of sleeve should be adequate, the thickness of sleeve corresponds to Sleeve Length, Flow Velocity and Flow Medium Temperature. The thickness increase factors shall be used on minimum sleeve thickness when,

the length of sleeve exceeds 18’’ (457 mm)

the flow velocity exceeds 31 m/sec

the flow medium temperature exceeds 149o C

S No Size (NB) Minimum Sleeve Thickness (mm)

1 2’’ – 3’’ 0.6

2 4’’ – 10’’ 0.9

3 12’’ – 24’’ 1.22

4 26’’ – 48’’ 1.5

5 50’’ – 72’’ 1.9

6 Above 72’’ 2.3



Vibration:

Bellows type Expansion Joints can be used for applications involving vibration provided if the vibration of

HIGH FREQUENCY & LOW AMPLITUDE

They are not suitable if the vibration of LOW FREQUENCY & HIGH AMPLITUDE, e.g., Reciprocating

Machines,

Bellows type Expansion Joints are not meant to remove vibrations especially resulting from Pressure

Pulses,

The system designer should consider, Pulsation Dampeners so that the vibration loads are not detrimental

to the function of the Bellows,

When the vibration is present and frequency is known, the metal Bellows can be designed in such a way

that its NATURAL FREQUENCY shall be LESS THAN 2/3 of system frequency or GREATER THAN 2 TIMES

the system frequency,



COLD SPRINGING

Defined as the Lateral or Angular Offset of the ends of the Expansion Joint, when installed,

Cold Springing is considered to reduce the force required to deflect the Expansion Joint, the preferredamount of cold springing is 50%,

In applications, where the Expansion Joint has to compensate huge lateral deflection, the angular rotationinduced on the individual Bellows in the assembly is also huge leading to instability,

By cold springing the Expansion Joint by 50%, at installation, the displacement of the convolution is reducedby 50%, thus the Expansion Joint will be more stable and with enhanced fatigue life.



EXPANSION JOINTS FOR FCCU

COLD SHELL CONSTRUCTION

Bellows Construction – 2 Ply testable

Annular Area Packed with Ceramic Pillow

Metal Seal to prevent the entry of catalyst in the annular area

External Insulation to prevent the temperature drop below dew point

Control Rods to limit individual Bellows Movements

Slotted Hinges to support dead weight of center section

Pantograph linkages to uniformly distribute the movements among the Bellows

Centre Gimbal to allow two plane lateral deflection

Heat Resistant & Abrasion Resistant Lining







EXPANSION JOINTS FOR FCCU

HOT SHELL CONSTRUCTION

Bellows Construction – 2 Ply testable

Annular Area Packed with Ceramic Pillow

Metal Seal to prevent the entry of catalyst in the annular area

Control Rods to limit individual Bellows Movements

Slotted Hinges to support dead weight of center section

Pantograph linkages to uniformly distribute the movements among the Bellows

Centre Gimbal to allow two plane lateral deflection

Abrasion Resistant Lining






Expansion Joints for CCR Platforming Reactors & Pacol Reactors

Incorporated in the internal piping of the Reactor,Compliance to ASME B31.3, Piping CodeTypical Design Temperature of 549o CTypical Design Pressure of 1.05 kg/cm2 (g), Differential,Bellows shall be of Single Ply, made out of Alloy 800 (ASTM B409 / ASME SA 409 UNS N08800)End Connection Flanges in SS 321 / SS 347 / A 182 Gr. F 11Removable type Internal Sleeve, with internal polished surface






Expansion Joints for Shell & Tube Heat Exchanger

Incorporated both on shell side & tube side,

When installed on shell side, should withstand the shell side pressure (internal) & full vacuum

When installed on tube side, should withstand both shell side pressure (external) & tube side pressure (internal)

Compliance to ASME Sec VIII Div. 1 Appendix 26,

The Expansion Joint should be designed individually for different operating conditions with cumulative fatigue verification,

Weld Ends shall be fully machined to meet the close tolerance on the clearance between shell inside dia and Baffle

Full bore Sleeve, to ensure smooth flow is considered,









Expansion Joints for High Temperature Process Piping

Preferably Single Ply Bellows,

Stainless Steel Material with ‘’H’’ grade, i.e., minimum carbon content of 0.04%,

Floating Ring type Tie Bar Supports with Shear Pads / Split Shear Rings to allow the radial growth of the pipe,




MANUFACTURING FLOW CHART – BELLOWS TYPE EXPANSION JOINTS


COMPONENT - BELLOWS COMPONENT-CONNECTING PIPES COMPONENT-FLANGES

COMPONENT-HARDWARE

Preparation of Sheet Layout & CuttingRolling of Sheet into cylinderLongseam Welding of Cylinder

NDE (as required)Forming of Bellows convolutions

NDE (as required)Trimming of Edges

Preparation of Layout & CuttingRolling into shell and longseam

weldingNDE (as required)

Machining (wherever required)Edge Preparation (wherever

required)

Flanges – Bought Out

Supports, Brackets, Lugs etc.,

Fabricated as per drawings

RAW MATERIALOrdering, Receipt at Stores, Inward Inspection, Identification & Correlation, Check Testing (wherever required)

ASSEMBLYFitment of Bellows element with Connecting Pipes & Welding

Fitment & Welding of Other ComponentsNDT (as required)

CLEANINGBellows element / SS Parts – With

Solvent / Pickling& PassivationExposed CS Parts – Blast / Power

tool cleaning

PAINTINGBellows element / SS Parts – Nil

Exposed CS Parts – Shop Primer / As required by Customer

MARKINGAffixing of Name Plate,

Marking of Flow Direction

Preparation for ShipmentFixing of Shipping

Brackets, Packing, Marking on Packing





Convolution Forming:

Mandrel Forming

Roll Forming / Roll Sizing

Hydro Forming

Elastomer Forming

Welding Process:

Bellows long seam Welding – GTAW in Semi Automatic Fixture

Bellows Edge Fusing – Resistance Seam Welding / GTAW

Bellows to Pipe attachment Welding – Similar & Dissimilar Welding – GTAW

Other Carbon Steel to Carbon Steel Welding – MIG / MMAW / SAW



Non Destructive Examination:

Bellows Long Seam

Prior to forming: 100% X – Ray / 100% LPEAfter forming: 100% LPE

Pipe Long Seam: 100% RT / 100% LPE / 100% MPI

Bellows to Pipe attachment weld: 100% LPE

Any other Butt Welds: 100% RT / 100% LPE

Any other Fillet / Load bearing Welds: 100% LPE

Leak Test: Pneumatic / Helium Leak Test (Optional) / Vacuum

Pressure Test: Hydrostatic @ ambient temperature @ specified pressure

Others: 100% Positive Material Identification (on Alloy Steel, Stainless Steel & High Nickel Alloy Parts)

Raw Material (Check Testing, if required)

Chemical CompositionMechanical: Tensile, Yield & % ElongationIntergranular Corrosion Check



Destructive Examination:

Squirm, Meridional Yield, Rupture & Fatigue Life Cycle

Squirm: The deformation of the convolution(s), beyond 15% UNDER PRESSURE. The Pressure at which the Bellows deforms beyond 15% is termed as Squirm Pressure;

Meridional Yield: The permanent deformation of the convolution(s), beyond 15% EVEN AFTER RELIEVING THE PRESSURE. The Pressure at which the permanent deformation occurs is termed as Yield Pressure;

Rupture: Gross deformation, Ballooning followed by rupture, the pressure at which the Bellows ruptures is termed as Rupture Pressure;

Fatigue Life Cycle: The number of cycles corresponding the movement that a Bellows undergo;


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Design-Engg-mfg-testing of Bellows Expansion Joints_442013144211