expansion joint new

Expansion Joint

Created By: Helmi

What are Expansion Joints

An expansion joint or movement joint is an assembly designed to safely absorb the heat-induced expansion and contraction of construction materials, to absorb vibration, to hold parts together, or to allow movement due to ground settlement or earthquakes.Regarding EJMA: Expansion joints are Any

device containing one or more bellows used to absorb dimensional changes, such as those caused by thermal expansion or contraction of a pipeline, duct or vessel.

Expansion Joint Function

• Maintaining the system stress within acceptable limits when using expansion loop is unacceptable due to space limitation and create unacceptable process condition.

• Maintaining the equipment nozzle load within acceptable limits when using conventional method is still unacceptable.

• When the equipment such as Compressors, Turbines, Pumps etc. necessitate isolating the mechanical vibrations from being transmitted to the connected piping.

Expansion Joint Type Based on Material

Metallic Expansion Joints• Metallic Expansion Joints are installed in pipe work and duct systems to

prevent damage caused by thermal growth, vibration, pressure thrust and other mechanical forces.

• Materials : all types of stainless steels and high grade nickel alloy steels.• Any pipe connecting two points is subjected to numerous types of action

which result in stresses on the pipe. Some of the causes of these stresses are:

– internal or external pressure at working temperature– weight of the pipe it self and the parts supported on it– movement imposed on pipe sections by external restraints– thermal expansion

• Application: 1) Heating and air conditioning installation 2) Hot water and fire protection system 3) Compressors inlet and outlet 4) Pipe with axial displacement by temperature or pressure changes 5) Thermal motors refrigeration circuit .

Rubber Expansion Joints• Rubber Expansion Joints are a flexible connector fabricated from natural

or synthetic elastomers and fabrics with metallic reinforcements designed to provide stress relief in piping systems due to thermal changes.When flexibility for this movement cannot be designed into the piping system itself, an expansion joint is the ideal solution.

• Movement compensation for lateral, torsional and angular movements.

• Problems solved like:– Vibration, Noise, Shock, – Corrosion, Abrasion– Stresses, Load Stress, – Equipment Movement– Vibration, Pressure Pulsation and – Movement in a Piping System

• Usage: It's widely used in water supply and drainage, Recycled water .Air conditioning , compressor .etc

Teflon® Expansion Joints

• Teflon® Expansion Joints corrosion proof, non-aging with extraordinary flex life and unmatched reliability.

• Usage:– widespread acceptance in the chemical processing industry, – piping applications where acids and highly corrosive chemicals

are being handled and – commercial heating and air conditioning systems as pump

connectors and a strategic point throughout a system.• They can be used to compensate for:

– Movement, Misalignment, Axial Travel– Angular Deflection, and or Vibration in Piping Systems

Expansion Joint Movement Types

• Axial Compression

Reduction of face-to-face dimension measured along the axis

• Axial Elongation

Increase of face-to-face dimension measured along the axis


• Transverse or Lateral MovementThe movement of the joint

perpendicular to the axis

• Vibration AbsorptionThe movement of the expansion

joint due to vibrations which

are effectively intercepted

and insulated against transmission

to remainder of systems.


• Angular Movement

The displacement of the

longitudinal axis of the

joint from its initial straight

line position (a combination

of axial compression)

Expansion Joint Type Based on

Usage/Function

Expansion Joint Type Based on Usage/Function

1) Simple Expansion Joint

2) Universal Expansion Joint

3) Hinged Expansion Joint

4) Pressure Balanced Expansion Joint

5) Gimbal Expansion Joint

1) SIMPLE EXPANSION JOINT

• The main use of single expansion joint in a piping system is to absorb axial & small amount of lateral & angular movements in which it is installed.

Expansion Joint for absorbing axial displacement:

• Single Element Bellow installed in a straight line

• Single Element Bellow installed in a straight line with an offset

• Double Element Bellow employing an intermediate anchor in the middle when installed in a straight line.

• Double Element Bellow employing a main anchor in the middle, installed in a straight line at the interface of changed line size (i.e. reducer).

• Three Element Bellow employing a main anchor in the middle, installed at the junction of the branch connection

Expansion Joint for absorbing lateral movement, angular rotation and combined

movement

• Single Element Bellow employing a directional anchor, installed in the longer leg of L shaped piping profile.

• Single Element Bellow

employing a directional

anchor, installed

in the shorter leg of

L shaped piping profile

Expansion Joint for absorbing lateral movement, angular rotation and combined

movement• Single Element Bellow employing a tie rod in place of a

directional anchor, installed on the shorter leg of L shaped profile

2) Universal expansion joint

• Universal expansion joints contain two bellows with multiple convolutions joined by a center pipe or spool, also known as double or tandem bellows expansion joints

• Usage: – absorbing any combination

of axial, lateral, or angular movements in a piping system.

– Accommodate : excessive lateral movements or limitation on the amount of lateral forces allowed on the connecting piping or equipment.


• Bellow with tie rod installed in a Z shaped piping profile in a single plane

• Bellow with tie rod installed in a Z shaped piping profile in two planes


• Bellow with pantographic linkage

3) HINGED EXPANSION JOINT

• Hinged expansion joints are usually used in sets of 2 or 3 elements to absorb lateral deflection in one or more directions in a single plane. The hinges are designed strong enough to take the axial pressure thrust and also to transmit the piping deflections in a plane perpendicular to the plane of hinge rotation.

• The magnitude of the lateral deflection that could be absorbed by a hinged bellow is directly proportional to the length of spool piece connecting the bellow elements.

3) HINGED EXPANSION JOINT• Two Element Bellow

• Three Element Bellow

4) Pressure Balance Expansion Joint

• The pressure balance expansion joint or bellow design, which basically is a combination of a Flow Bellow and a Balancing Bellow.

• The axial thrust imposed by the imbalance area of the Bellow under internal pressure is a main concern in designing the Piping System employing such Bellows. The conventional method of designing such systems is by employing Main Anchors to absorb the above axial force. It is however not always practical (due to space/ access constraints) to achieve these conventional solutions. The excessive magnitude of the axial force could also become prohibitive in some instances.


• The working principle of the above Bellow relies on the fact that since both Flow and Balancing Bellow have identical cross sectional area, they will produce equal, but opposite in direction, forces under the same internal pressure. If the ends of these Bellows are locked to each other by a suitably designed tie-rod, the above equal and opposite forces will cancel out to transmit no axial force on the end terminals of the connected piping. At the same time the above tie rod will not interfere with the Flow Bellow in absorbing axial/ lateral deflections.


• Single Element Bellow installed at the 90 O turning of a piping profile


• In-line Pressure Balanced Bellow

• Double Element Bellow installed at the 90 O turning of a piping profile for absorbing large lateral movements


The gimbal pipe expansion joint is basically same as the hinge type, except that instead of being limited to deflection in only one plane gimbal Expansion Joints are used to absorb angular rotation in any plane, using two pairs of hinges attached to a common floating gimbal ring.

.


• Main features of Gimbal Expansion Joint:• Permits angular movement in any plane• Eliminates pressure thrust forces• Transmits shear and wind loads, so low forces on

the pipe anchors• No main anchors required• Prevents torsion or twisting of the expansion joint• Internal flow liners for eliminating velocity problem• Anchors only required to absorb spring forces• Low forces on piping system


• Advantages of Gimbal Expansion Joint:• Absorbs angular movements in all planes and

angular rotations, or any combinations of these• Eliminates pressure thrust loads• Positive control over the movements• Supports dead weight of the intermediate piping• Transmits external loads like wind loading and

shear loading• Prevents torsion on the bellows elements• Guiding requirement is minimized• Eliminates main actors


• Limitations of Gimbal Expansion Joint:

• More space is required for gimbal bellows joints as compared to axial expansion joints

• Change of pipe direction is required

• Two or more gimbal expansion joints required to work as a system


• Applications of Gimbal Expansion Joint:• Engines• Steel mills• Petro Chemical• Power Generation• Shipbuilding industry• Water treatment• Cement plants• Paper industry

Consideration To Select Expansion Joints

• Choose tentative location for the pipe anchors which their amount and locations will depend on:– the piping configuration– The amount of expansion which can be

accommodated by one expansion joint– the availability of the structural members used for

anchors

– Location of various pipe fittings

– Location of connected equipment

– Location of branch connections and etc.


• The major pieces of connected equipment such as turbines, pumps, compressors, heat exchangers, reactors, and similar device can be considered as anchor.

• It is necessary to use additional anchors at valve, at changes in the direction of pipe, at the blind ends of pipe and at major branch connection.

• Use the simplest and the most economical layout


• Unless any advantage can be obtained from another approach

• Conform the movement based on pipe layout

• Cost, the ability to comply with cyclic life and force requirements, space restriction, etc should be considered.


• Calculate actual change in length of each leg of each individual pipe section due to expansion with min/installation temperature basis is 70o F or 21o C otherwise specified.


• Allowance must be taken due to possibility as follow:– Error in assumption basis of min/installation

temperatures of metal/piping material.– Caused by problem encountered at the job

site during erection of piping, the anchor point is relocated

– During operation the system may be subjected to a different temperature range than designer anticipated, particularly during start up.

expansion joint new

Documents