Twin Sphere Joint (FTC)

Twin Sphere Joint (FTC)

Category: Expansion Joint

Specifications
Details

A Twin Sphere Joint, sometimes referred to as a Twin Sphere Rubber Expansion Joint, is a flexible connector designed with two spherical bellows to absorb movement, vibration, and noise in piping systems.
The FTC type generally indicates a Flanged Type Connector, where the rubber body is fitted with integral or floating flanges for secure installation.


Construction

  1. Body

    • Material: Reinforced synthetic rubber such as EPDM, NBR, or Neoprene (depending on media).

    • Design: Two spherical bellows increase flexibility and movement absorption.

  2. Reinforcement

    • Multiple plies of high-strength synthetic fabric, sometimes combined with steel wire reinforcement for higher pressure.

  3. End Fittings

    • FTC Type: Flanged connections, either fixed or floating, in carbon steel, stainless steel, or ductile iron.

    • Flanges drilled to standards such as ANSI, JIS, DIN, or BS.

  4. Inner Liner

    • Rubber grade selected to resist specific media (water, oil, chemicals, etc.).


Typical Specifications

  • Size Range: DN25 (1") to DN1200 (48") or larger.

  • Working Pressure: 10 bar (PN10) standard, higher ratings available on request.

  • Vacuum Resistance: Up to –650 mmHg with internal vacuum support.

  • Temperature Range: –20 °C to +100 °C (depending on rubber compound).

  • Movement Capability:

    • Axial Compression: ~20–30 mm

    • Axial Elongation: ~10–15 mm

    • Lateral Deflection: ~15–20 mm

    • Angular Deflection: up to 15°


Applications

  • HVAC Systems – vibration isolation for pumps, chillers, and cooling towers.

  • Water & Wastewater – flexible connections for pipelines in treatment plants.

  • Industrial Piping – chemical plants, oil refineries, and power stations.

  • Marine & Offshore – seawater and ballast water systems.

  • Pumps & Compressors – absorb pulsations and reduce stress on equipment.


Advantages

  • Twin sphere design provides greater movement absorption than single sphere joints.

  • Noise & vibration reduction improves system performance.

  • Corrosion-resistant construction with suitable flange and rubber material selection.

  • Long service life under dynamic conditions.

  • Easy installation with standard flanged ends.


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