Definition of an Expansion Board

Principal function: Contain fluid with a pressure other than atmospheric.
Main advantage
: The flexibility in the axial direction

FUELLE

Geometry of an Expansion Board

EXTREME (CONNECTIONS)
BRIDAS

Geometry of an Expansion Board

Flanges

Standardized accessories and are classified by means of “pressure features” The standards of flanges most used are those that govern the ANSI code (American National Standard Institute), with ranges of 150, 300, 400, 600, 900, 1500 and 2500 psi. In addition to these standards there are others such as API (American Petroleum Institute), AWWA (American Water Works Asso- ciation), MSS (Manufacturing Standarization Society), DIN (Deutsche Industrie Normen), etc. All Americans except the last, German. Expensive pieces, due to the amount of material they have, but they have a great advantage that they are assembled and disassembled with great ease, which helps in their maintenance or replacement.

Geometry of an Expansion Board

 EXTREME (CONNECTIONS)

WELDED EXTREMES

Geometry of an Expansion Board

EXTREMOS (CONNECTIONS) FITTINGS

Mechanical elements, usually carbon steel that serves mainly to guide and direct the movements that a J.E. it must absorb, also to resist the pressures that arise from pressure. Common elements: braces, ears, brackets and hinges.

Considerations for the application of an Expansion Board

FLUID PRESSURE AND SPEED
It is necessary to know the effect of pressure and fluid velocity in a pipe, to determine:

The magnitude of the force that anchors must resist. Know the number of guides to use in a pipe system provided with one or several expansion joints.

PRESSURE PUSHES (STATIC EFFECT)

FORCES BY CHANGE OF FLUID DIRECTION (DYNAMIC EFFECT)

In the case of a closed pipe or duct, the force due to the change of direction, as well as the pressure thrusts, is resisted by the walls of the pipe in the axial direction. But in the case of a system containing an expansion joint, the force must be resisted by the anchors or tension rods, whichever is the case.

FORCES BY FRICTION

Friction forces occur with or without pipe movement (when trying to move). The type of support used within a certain structure determines the coefficient of friction and based on this there are two types of supports:

SLIDES: This type of supports is the most used for the simplicity of construction and despite producing large coefficients of friction, the problems due to high friction forces are not serious.

BEARINGS OR ROLLERS: In these there is no friction between the support and the structure, but a bearing without sliding so it eliminates or greatly reduces the value of the forces by friction.

ANCHORS AND GUIDES

MAIN AND SECONDARY

The difference between the main and secondary anchors, is that the first resist the pressure thrusts and the forces for change of direction and the secondary ones, both must withstand the forces that are required, to deform the bellows of the joint and forces by friction.

ANCHORS AND GUIDES

Alignment and flat guides

There are guides for general use to control the pipe system, which, while restricting movement in the two transverse axes, do not have the required adjustment for the use of simple expansion joints without straps to absorb axial movement, so they should not be used Examples are structural elements such as “T” or “I” joined to the pipe and restricted by angles or clamps. The types of guides suitable for the application of J.E. They may be: 3 or 4 rollers attached to a structure. 4 brackets attached to the pipe and restricted by a jacket or outer tube. 4 structural elements joined to the pipeline and restricted by a suitable cover.

ANCHORS AND GUIDES

Alignment and flat guides

The functions of the alignment guides when restricting lateral movements are: Orient the axial movement of the pipe towards the bellows, so that it absorbs the thermal expansion.

Prevent the bellows from loading the weight of the pipe. Fix the ends of the expansion joint and provide stability. Prevent buckling of the joint and pipe, or of the pipe.

Types of Expansion Joints

SIMPLE
It only consists of a bellows and its ends. The movements that this joint can absorb are mainly axial and small lateral. As they do not have tension rods (tie rods) that resist pressure thrusts, they require main anchors and alignment guides. The main application is that in which the board absorbs axial movement in a straight pipe, where the absorbed axial movement is large.

Types of Expansion Joints

Types of Expansion Joints

Types of Expansion Joints

SIMPLE WITH STRAPS

They resist the thrusts by pressure and therefore do not absorb axial movement. The movements that absorb these are lateral and the axial thermal expansion between the tension rods (tie rods).

The guides that are required are only to orient dilatations and control the pipe arrangement.

Types of Expansion Joints

SIMPLE WITH STRAPS

 In the arrangement that connects the equipment in the figure, the thermal expansion of the pipe and the movement of the equipment in the vertical direction is absorbed by the expansion joint.

Types of Expansion Joints

SIMPLE WITH STRAPS

Typical applications:

Types of Expansion Joints

UNIVERSAL

Types of Expansion Joints Absorbs large lateral movements and expansion Axial of the section between the tension rods (tie rods). It is not advisable to use excessively long central tubes to absorb very large lateral movements, as there is a danger of leaving an unstable system.

Types of Expansion Joints

HINGE

They absorb only angular movements in a plane and the articulated plates or hinges orient the movements and resist the thrusts by pressure.

They are always used in sets of two or three joints, in order to absorb large lateral movements, because in the same way as in universal joints, the greater the distance in which they are placed, the greater the lateral movement that they absorb.

Types of Expansion Joints

UNIVERSAL

Typical applications: