Fabric Expansion Joint
RADCOFLEX: Fabric Expansion Joint
Radcoflex products are used extensively throughout many industries for a wide variety of applications including the conveying of materials and gases, mechanical protection, pipeline movement control and vibration absorption.
Fabric Expansion Joint
Fabric expansion joints compliment the Radcoflex range of metal expansion joints, and provide a viable alternative in applications requiring a light weight joint, relatively low temperatures and zero spring rate. Typical applications include ventilation ducts, flue gas ducts, de dusting ducts, turbine exhausts, breach seals, energy refuse and wet scrubber service, where vibration needs to be absorbed. When selecting a fabric expansion joint it is most important to select a fabric suitable for the application. Radcoflex supply four basic fabric styles all offering high chemical resistance, suitable for dry, moist and wet applications.
Typical applications
Fabric expansion joints compliment the Radcoflex range of metal expansion joints, and provide a viable alternative in applications requiring a light weight joint, relatively low temperatures and zero spring rate.
Radcoflex fabric expansion joints are suitable for a wide range of applications including:
- Fans – Baghouses
- Coal Feeding – Flue Gas Ducting
- Absorbers – Stack and Breaching Seals
- Recovery Boilers – Wet and Dry Scrubbers
- Precipitators – Power Boilers
- Turbine Exhaust – Grate Seals
Typical applications include ventilation ducts, flue gas ducts, de dusting ducts, turbine exhausts, breach seals, energy refuse and wet scrubber service, where vibration needs to be absorbed.
Fatigue life
The fatigue life of an expansion joint can be defined as the total number of complete cycles which can be expected from the expansion joint based on data tabulated from tests performed at room temperature. A cycle can be defined as one complete movement of the joint from its initial position to its moved position and back again.
The fatigue life of an expansion joint is affected by a number of factors including:
- the operating pressure – the operating temperature
- the bellows material used – the thickness of the bellows material
- the movement required per convolution
- the height, shape and pitch of the convolutions
- bellows heat treatment requirements
A change in any of these factors will change the life of the expansion joint.
The standard Radcoflex catalogue listed expansion joints (with the exception of the externally pressurized AXI – line joints) have an expected life of 5000 full cycles.
Specifications
Component Fabric Expansion Joint
Radcoflex is continually developing materials which maximise corrosion resistance, flexibility and strength. As with our metallic expansion joints, fabric membranes must be strong enough to resist system pressure yet still be flexible. Please find below an outline of the components of our fabric expansion joints using the latest heat sealable fluoropolymer materials.
Pressure Balanced Joints
A. Gas seal membrane
The gas seal membrane is selected to withstand the pressure of the system and be resistant to chemical attack from the interior and the exterior. All our gas seal membranes are flexible so as to absorb thermal movements. As the temperature increases insulating layers are added to protect this membrane from damage.
B. Insulating layers
The insulating layers for CHEMSEAL (C1 to C4) provide thermal protection to the inside layer of the gas seal membrane. This layer also helps to reduce condensation caused by the gas stream contacting the cooler surface of an uninsulated gas seal membrane.
C. Retaining mesh
The retaining mesh is provided to protect the insulating layers from erosion and maintain thermal integrity. This mesh is usually of stainless steel material.
D. Back up bars
Back up bars are positioned above the gas seal membrane so as to apply clamping pressure to the fabric and duct flange whilst also restraining the fabric from moving under the system pressure. Back up bars have radiused edges so as to protect the gas seal membrane from wear damage near the back up bar.
E.Metal flow liner
Liners protect the fabric expansion joint from abrasive particles, and to reduce flutter of the fabric membrane caused by turbulence. A flow liner helps to reduce the temperature impact on the fabric element.
F. Fly ash seals
Our braided stainless steel fly ash seal are intended to deter fly ash building up in the expansion joint cavity. All our fly ash seals are capable of retaining their strength and flexibility while being exposed to maximum system temperatures and pressures.
G. Flange gasket seal
Flange gasket tape is used to seal the gas seal membrane to the mating duct flanges, as well as protecting the gas seal membrane from abrasion.
