Axial Expansion Joint

ASHOK ENGINEERING WORKS’ custom design metal bellows are in accordance with the Expansion Joint Manufacturer’s Association (EJMA) guidelines. We supply pre-engineered metal bellows, to meet the customer’s individual requirements.

Our strict manufacturing processes and quality control procedures insure a precise metal bellows every time. Single ply and multiply metal bellows are available in sizes up to 1000 NB diameter. Metal bellows can be made in most alloys.

It is used for axial movement only in pipe configurations. However, it can also absorb small amounts of other two types of basic movements viz. lateral and angular.

  • Unrestrained Axial expansion joint
  • Restrained Axial Expansion joint

Unrestrained Axial expansion joint

This type of bellows, dose not have any restraints or guides, so it can resist deflections due to spring rate of the bellow elements. The bellow should be adequately guided and anchored to avoid unexpected movements and proper functioning of the expansion joint.

Advantages

  • Inexpensive
  • Low maintenance
  • Absorbs all three types of movement
  • Easy to install
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Restrained Axial Expansion joint

It has all the characteristics of the unrestrained expansion joint with addition of tie-rods to restrain the pressure thrust and to restrict the movement of expansion joint. The tie-rods are arranged in opposite to each other or at an interval of 90 degrees

Advantages

  • Inexpensive
  • Absorbs all three types of movement
  • Absorbs system pressure thrust
  • Easy to install
  • Low maintenance
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Universal Expansion Joint

This bellows are designed and manufactured as per EJMA. In this type of expansion joint Two bellows connected by a common connector or centre piece, is called Universal expansion joint. These are used to absorb large amount of lateral deflections. Universal expansion joints can also absorb other two types of movements like axial and angular. Double expansion joint is different from Universal expansion joint.

Single ply and multiply universal expansion joint are available in sizes up to 1000 NB diameter. Metal bellows can be made in most alloys.

Advantages

  • Simple and robust construction.
  • Absorbs large amount of lateral, angular and axial movements.
  • Low maintenance
  • Inexpensive
  • Easy to install
  • Un-Restrained Universal expansion joint

    This type can absorb large amount of lateral deflections and it can absorb axial and angular movements too. To absorb large amount of lateral deflection, the length of the centre piece can be increased to accommodate it. Usually Universal expansion joints are provided with control rods to distribute the movement equally between the two bellows. Control rods can not withstand pressure thrust.

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  • Restrained Type Universal expansion joint

    It is same as unrestrained type expansion joint, but it has tie-rods. These tie rods are designed to withstand the pressure thrust and so the external movement of the expansion joint is constrained even if the pressure thrust is increased. If we need to accommodate angular movement in one plane only, than two tie rods are provided 180 degree apart. To restrict this angular movement, four tie rods are provided at in interval of 90 degrees, around the circumference of the expansion joint.

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Gimbal Expansion Joint

A gimbal expansion joint can absorb angular deflection in any plane. It consists of two pairs of hinges connected to a common floating ring. Gimbal Expansion joint can consist of a single bellow, where there is no lateral deflection, if there is any Lateral deflection, than two bellows connected by a common connector. The pairs of hinges, gimbal pin and the gimbal floating rings are designed to restrain the pressure thrust.

Single ply and multiply metal expansion bellows with gimble are available in sizes up to 1000 NB diameter. Metal bellows can be made in most alloys.

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Advantages

  • Permits angular movement in any plane.
  • Gimbal pins are designed to withstand the pressure thrust, so the load on the anchors is reduced.
  • Reduced forces on the piping system and main anchors.
  • Resists extraneous forces created form wind loads, piping loads, dead weight of the machinery, etc.
  • Prevent torsional movement of expansion joint as the two pairs of the hinge pins are connected to the gimbal ring.

Pressure Balanced Joint

Inline pressure balance expansion joint is designed to absorb axial, lateral and angular deflection, while restraining the pressure thrust exerted by the internal pressure and without a change in direction of the piping. This pressure thrust is restrained by the tie rods , which connects the line bellows and the balancing bellows. It is a constant volume system, so the Main Anchors can be designed as intermediate anchors, and function only to direct the thermal expansion of the pipe towards the expansion joint.

An Inline Pressure Balance expansion joint consist of two line bellows and a balancing bellow, Balancing below has effective area twice than that of line bellows. The line bellows absorb the axial and/or lateral movement while restraining the pressure thrust by the means of the tie devices interconnecting the balancing bellow. Each bellows are designed to absorb the axial movement while the line bellows are designed to absorb the lateral deflections also.

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Rectangular Joints

These type of expansion joints are made as per EJMA. Ashok Engineering Works can manufacture rectangular expansion joint having no size limitation. These type of expansion joint are provided with various configuration of corners Like round, single miter, double miter and camera corners.

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