(Flex25) Composition and Specification
Structure of Flex25 products:
All Flex25 duct/flue liner tubes consist of three layers:
Internal Layer: thermoplastic hose (Removed after installation is complete)
Composite Layer: glass fibre impregnated with heat-resistant resin
External Layer: thin textile cover woven from synthetic fibre
Installation Equipment: Specialised Flex25 Steamer
The internal layer facilitates installation, it is a thin-walled (100 - 150 microns) plastic hose made of a mixture of thermoplastic components. Its size suits the desired diameter. Removed when the installation is complete.
The intermediate composite layer is the heat, flame and corrosion resistant structural material of the Flex25 liner tube. Composite means resin of high solidity reinforced with thin glass fibres. The resin surrounds and embeds in the glass fibres, cementing them to each other. The resin transfers forces from one glass fibre to another and protects the glass fibres from corrosion. The solidity of composite materials is determined by the amount, type and direction of the fibres which are thinner than a hair.
One square metre of the 2-mm thick wall structure of the Flex25 liner tube contains 3,000,000 metres of glass fibre. The diameter of the reinforcing glass fibres in Flex25 is 13 microns, which are used in the form of fabric.
The rigidity of glass fibres is the same as that of steel, but they are three times lighter. The resin developed for the Flex25 liner tube is a liquid material consisting of a mixture of several components.
This resin is a material isn't naturally found and has taken years of R&D development. The difficulty is how to harness this liquid resins properties and bring it to projects and different applications.
External layer: The external layer is a thin fabric woven from synthetic fibre. Its function is to protect the composite layer and to ensure the exact perimeter of the chimney tube. Its other function is to form a homogenous external surface.
How the resin is harnessed:
Its viscosity is similar to that of honey. When it is cold it becomes more viscous, when it is warm it is more fluid.
Soft not Liquid "B" State:
A catalyst agent is added to the Pressed layers of the resin, it changes from the liquid state into a state that is no longer liquid. It can be held in the hand and bent. It can be stored in this state for a certain amount of time, this is the state the liner will arrive on site as.
When exposed to heat the pressed and catalyzed resin will now harden. Once it has hardened, it cannot be softened again. It has now changed from a flexible and bendable material to a solid structural material with excellent heat and corrosion resistance properties.
Installation Equipment used:
To complete the final catalyzation step the liner needs to be introduced to heat when it is in the flue/ duct, so that it expands to its desired shape and size. This liner is capable of having varying diameter in one liner with bends also possible. So steam is the best way to deliver the heat throughout the liner to complete the process. So installers have a hi-tech steam generator purposely built for installations of Flex25 liners. The size/diameter/product type will effect the time for the installation process to be finished.
This is how the liner leaves the factory, you can see how flexible the liner is at this stage because 11.5M liner fits in such a small box. It is able to be folded in this state.
The cured version can come in diameters 80 - 1000mm lengths up to 100M, one continuos piece with varying diameters throughout one lining possible (the image is an example of the varying diameters possible).
This is how the liner leaves the factory, you can see how flexible the liner is at this stage because 11.5M liner fits in such a small box