INSTALLATION GUIDELINES

Single bellows assembly axial unrestrained expansion joints will not be provided with attachments such as tie rods or hinges to retain pressure thrust. Therefore they can be used only in a ducting system that incorporates correctly designed anchors duct alignment guides. These components prevent the bellows from over extension and damage due to distortion under operating conditions.

    TYPES OF ANCHORS
  • MA Main Anchors
  • IA Intermediate Anchors
  • DA Directional Anchors

EXPANSION JOINT COMPONENTS AND RELATED EQUIPMENT

  1. ANCHORS
    1. MAIN ANCHOR

      A main anchor is one which must withstand the full bellows thrust due to pressure, flow, spring forces etc. A main anchor base for connection to the anchor structure can be furnished as an integral part of a Single or Double Expansion Joint, if desired. However, we must be advised of the magnitude and direction of all forces and moments which will be imposed upon the anchor base so that it can be adequately designed to suit the specific application.

    2. INTERMEDIATE ANCHOR

      An intermediate anchor is one which must withstand the bellows thrust due to flow, spring forces etc., but not the thrust due to pressure. An intermediate anchor base for connection to the anchor structure can be furnished as an integral part of a Single of Double Expansion Joint, if desired. However, we must be advised of the magnitude and direction of all forces and moments which will be imposed upon the anchor base, so that it can be adequately designed to suit the specific application.

    3. LIMIT RODS

      Devices, usually in the form of rods or bars, attached to the Expansion Joint assembly whose primary function is to restrict the bellows movement range (axial, lateral and angular) during normal operation. In the event of a main anchor failure, they are designed to prevent bellows over-extension or over-compression while restraining the full pressure loading and dynamic forces generated by the anchor failure.

    4. PANTOGRAPH LINKAGES

      A scissor-like device. A special form of control rod attached to the expansion joint assembly whose primary function is to positively distribute the movement equally between the two bellows of the Universal Joint throughout its full range of movement. Pantograph linkages, like control rods, are NOT designed to restrain pressure thrust.

    5. PIPE ALIGNMENT GUIDE

      A pipe alignment guide is a form of framework fastened to some rigid part of the installation which permits the pipe line to move freely in only one direction, along the axis of the pipe. Pipe alignment guides are designed primarily for use in applications involving lateral deflection and angular rotation.

    6. PIPE SECTION

      A pipe section is that portion of a pipe line between anchors. All dimensional changes in a pipe section must be absorbed between these two anchors.

    7. PLANAR PIPE GUIDE

      A planar pipe guide is one which permits transverse movement and/or bending of the pipeline in one plane. It is commonly used in applications involving lateral deflection or angular rotation resulting from "L or "Z shaped piping configurations.

    8. PURGE CONNECTIONS

      Purge connections, where required, are usually installed at the sealed end of each internal sleeve of an Expansion Joint for the purpose of injecting a liquid or gap between the bellows and the internal sleeve to keep the area clean of erosive and corrosive media and/or solids that could pack the convolutions. Purging may be continuous, intermittent or just on start-up or shut down, as required. These are sometimes called aeration connections.

    9. DIRECTIONAL ANCHOR

      A directional or sliding anchor is one which is designed to absorb loading in one direction while permitting motion in another. It may be either a main or intermediate anchor, depending upon the application involved. When designed for the purpose, a directional anchor may also function as a pipe alignment guide. In the design of a directional anchor, an effort should be made to minimize the friction between its moving or sliding parts, since this will reduce the loading on the piping and equipment and ensure proper functioning of the anchor.

    10. BELLOWS

      The flexible element of an Expansion Joint, consisting of one or more convolutions and the end tangents, if any.

    11. CONTROL RODS

      Devices, usually in the form of rods or bars, attached to the Expansion Joint assembly whose primary function is to distribute the movement between the two bellows of a Universal Expansion Joint. Control rods are NOT designed to restrain bellows pressure thrust.

    12. COVER

      A device usee to provide limited protection of the exterior surface of the bellows of an expansion joint from foreign objects or mechanical damage. A cover is sometimes referred to as a shroud.

    13. CONVOLUTION

      The smallest flexible unit of a bellows. The total movement capacity of a bellows is proportional to the number of convolutions.

    14. EQUALIZING AND REINFORCING RINGS

      Devices used on some Expansion Joints fittings snugly in the roots of the convolutions. The primary purpose of these devices is to reinforce the bellows against internal pressure. Equalizing rings are made of cast iron, steel, stainless steel or other suitable alloys and are approximately "T shaped in cross section. Reinforcing or root rings are fabricated from tubing or solid round bars of carbon steel, stainless steel or other suitable alloys.

    15. FLANGED ENDS

      The ends of an Expansion Joint equipped with flanges for the purpose of bolting the expansion joint to the mating flanges of adjacent equipment or piping.

    16. INTERNAL SLEEVE

      A device which minimizes contact between the inner surface of the bellows of an Expansion Joint and the fluid flowing through it. These devices have also been referred to as liners, telescopic sleeves etc.

    17. SHIPPING DEVICES

      Rigid support devices installed on an Expansion Joint to maintain the overall length of the assembly for shipment. These devices may also be used to pre-compress, pre-extend or laterally offset the bellows.

    18. TANGENTS

      The straight unconvoluted portion at the end of the bellows.

    19. TIE RODS

      Devices usually in the form of rods or bars, attached to the expansion joint assembly whose primary function is to continuously restrain the full bellows pressure thrust during normal operation while permitting only lateral deflection. Angular rotation can be accomodated only if two tie rods are used and located 90 degrees opposite to the direction of rotation.

    20. WELD ENDS

      The ends of an Expansion Joint equipped with pipe suitably bevelled for welding to adjacent equipment or piping.