Bellows type expansion joint Bellows type expansion joints manufactured by OSK shall be introduced in following pages.

Bellows type expansion joint

  • Free Type(SS Type)

    This expansion joint has a basic and simple structure with pipes and flanges attached to both ends of the bellows and is used for low pressure piping lines. If the lateral deflection is large, two bellows parts are used as a double type to accommodate it. NO flange type expansion joint is available.

    Free Type(SS Type) Free Type(SS Type)
  • Tie Rod Type(SF Type)

    In the case of the higher internal pressure, guide flanges and tie-rods to both end portions of the bellows are installed to prevent deformation of the bellows.

    Tie Rod Type(SF Type) Tie Rod Type(SF Type)
  • Ring Type(SC Type)

    In the case of furthermore higher internal pressure, by attaching equalizing and reinforcing rings to each corrugation of the bellows, the convolutions are prevented from deformation.

    Ring Type(SC Type) Ring Type(SC Type)
  • Universal Type

    It is capable of absorbing displacement in the axial movement and in the lateral deflection at the same time. Internal pressure thrust is restricted by the tie-rod, which does not act on the anchor.

    Universal Type Universal Type
  • Hinge Type

    It is effective for piping where anchors can not be accommodated completely such on the top of a tower or those around an apparatus. With hinge pins and arms, the both end are held to bind internal thrust load and only force required for bending the bellows acts on the anchor. Combining 2 or 3 pieces of Hinge Type of Expansion Joint on a single plane, integrated axial movement can be absorbed.

    Hinge Type Hinge Type
  • Gimbal Type

    Gimbal Type of Expansion Joint consists of two set of hinge pins and arms on the Gimbal ring at 90°degrees, which is capable of absorbing displacement combined in two direction at the same time.

    Gimbal Type Gimbal Type
  • In-line Type Pressure Balanced

    In-line pressure balanced expansion joint is designed to absorb axial movement and/or lateral deflection while restraining the pressure thrust by means of tie devices interconnecting the line bellows with outboard compensating bellows also subjected to line pressure, Each bellows set is designed to absorb the axial movement and usually the line bellows will absorb the lateral deflection. This type of expansion joint is used in a straight run of piping.

    In-line Type Pressure Balanced In-line Type Pressure Balanced
  • L Type Pressure balanced

    L type pressure balanced expansion joint can absorb expansion and contraction without generating thrust load in the straight of the piping. The outboard compensating bellows can be arranged in other direction, compared to in-line type pressure balanced expansion joint, The interference with adjacent piping can be mitigated when arranged in parallel.

    L Type Pressure balanced L Type Pressure balanced
  • Bent Type Pressure balanced

    In angle type of pressure balanced expansion joint, the bellows is placed in the straight run of the curved pipe and the compensating bellows are connected behind the elbow and the internal pressure thrust is canceled out in the expansion joint. If the bellows are double, the further more larger lateral deflection can be absorbed.

    Bent Type Pressure balanced形 Bent Type Pressure balanced
  • Jacket Type

    In the case of fluid becoming solid or high viscosity in ambient temperature, in order to assure the liquidity by heating up, the bellows has a double pipe structure where the product flows in its inner side and the heating medium flows in its outer side.

    Jacket Type Jacket Type
  • Rectangular Type

    This expansion joint is suitable for a rectangular duct in a low pressure. In the case of large lateral defection, the double bellows type are applied. There are two types of the corner shape for “single miter corner” and “rounded corner” which relatively absorb larger displacement than miter. The OSK make round type has no longitudinal weld on the corner and higher reliability.

    Rectangular Type Rectangular Type

Classification of expansion joint type


  • 1.Type
    3H: 3 sets of Hinge 2H: 2 sets of Hinge 1H: 1 set of Hinge 2G: 2 sets of Gimbal 1G: 1 set of Gimbal
  • 2.Operative direction
    X: Axial Movement Y: Lateral Deflection Z: Other lateral deflection θ: Angular Rotation
  • 3.Load acted on anchor
    FB: Spring load FP: Pressure thrust 〇:Loaded ×:NO Non-loaded △:Loaded, depending on the usage
Type Operative direction Load acted on anchor
Free Type SS
Tie-Rod Type SF
Ring Type SC
Universal Type
Hinge Type 3H ×
2H ×
1H ×
Gimbal Type 2G+1H ×
2G ×
1G ×
In-line type
Pressure balanced
Single ×
Double ×
L type
pressure balanced
Single ×
Double ×
Angle type
pressure balanced
Single ×
Double ×
Rectangular type
Thick bellows type

※Can be scrolled horizontally