Technologies
A core business activity of the Group is the ownership and sale of technologies for pipe manufacturing. Amiantit wholly or jointly owns a couple of leading technology companies and has a close relationship with several others, making it a worldwide leader in pipe technology. Key technologies cover development and Research on glass reinforced polyester (GRP), glass reinforced epoxy (GRE), ductile iron, and polymer concrete pipes. Licensees all over the world work with Technologies developed by the Amiantit Group.
GRP- Continuous Winded
The technology for development and manufacture of GRP pipes named “Flowtite” has started in the late 1960s. It is a continuous filament winding process which represents the state of the art in GRP pipe production. This process allows the use of continuous glass fiber reinforcements in the circumferential direction. For a pressure pipe or buried conduit the principle stress is in the circumferential direction, thus incorporating continuous reinforcements in this direction yields a higher performing product at lower cost. Using technology developed by material specialists, a very compressed laminate is created that maximizes the contribution from three basic raw materials. Both continuous glass fiber rovings and choppable roving are incorporated for high hoop strength and axial reinforcement. A sand fortifier is used to provide increased stiffness by adding extra thickness with placement near the neutral axis in the core. With the Flowtite dual resin delivery system, the equipment has the capability of applying a special inner resin liner for severe corrosive applications while utilizing a standard type resin for the structural and outer portion of the laminate. Taking advantage of the winding process, other materials like glass veil or polyester veil can be used to enhance the abrasion and the chemical resistance and the finishing of the pipe. The Flowtite filament winding technology represents the most advanced state-of -the-art technology in use, and is the foremost method of manufacturing a glass fiber pipe.
GRP – Centrifugally Cast
Amiantit also develops GRP solutions using the centrifugal casting process for manufacturing. The raw materials (Resin, chopped glass, sand and fibers) are fed in a high speed rotating mould so that the pipe wall is completely de-aired and void free.
The technology is using rotating moulds where a feeder arm distributes the raw materials evenly over the whole length of the pipe. Layer by layer, resin, chopped fiber glass and silica sand is released in the invert of the rotating pipe moulds. By varying the amount of raw materials in each layer the project specific pipe properties are being adjusted.
GRE – Cross Helical Winded
The Amipox Technology works with high strength fiberglass (E-glass) and amine cured epoxy resin. These materials provide the optimal strength in this specially designed composite pipe systems. Numerically controlled machines manufacture the product on a mandrel in a cross section filament winding process. The continuous glass fibers are wound with a precisely defined helical angle and connected with the epoxy resin. This process, combined with the most modern equipment, ensures a consistent production of the highest quality. For certain applications, the pipe wall contains an extra liner of 0.5 mm. This optional resin rich liner consists of C-glass (C-veil) and the same resin as used in the pipe wall.
Ductile Iron
Ductile iron is distinguished from ordinary grey iron by its remarkable mechanical properties (elasticity, impact strength, elongation...). These are due to the spheroidal nature of the graphite particles. Molten metal is provided by a blast furnace. After desulphurization, tailor-made chemical compositions can be made by adding scrap metal or specific ferro-alloys. Magnesium is introduced into the molten metal, to render it ductile. The manufacturing technology consists of a spinning process where molten iron is brought inside a rapidly rotating cylindrical mold and the solidification of the metal happens by continuous mould cooling. The following graphitizing, then ferritizing heat treatment obtains the pipes with the required structure and mechanical properties.
On leaving the heat treatment furnace, the pipes receive an external coat of pure metallic zinc, applied by electric arc melting of zinc wire and spraying with compressed air.
Polymer-Concrete
The polymer concrete technology is a vertical casting process, very similar to concrete pipe technology. Exact amounts of polyester resin, quartz sand, silicate aggregate and quartz filler are pre-mixed, with the raw material quantities, mixing sequence and material feeds controlled by a computer. Then, the mixed material is loaded into vertical moulds where vibratory compaction is used to ensure a dense, void-free composite structure. The polymer concrete pipe is initially cured in the moulds. Once a rigid structure has set, the moulds are stripped and the pipe is post-cured in a tunnel kiln. Manufacturing in dimensionally accurate steel casting moulds produces pipe systems with very tight dimensional tolerances, circular over the entire length. This process is used for producing round pipes, non-circular pipes and special structures (e.g. manholes and wet-wells) as well as elliptical, semi-elliptical and egg-shaped pipes. Pipes with circular outside diameters to aid tunneling, but with non-circular interiors, can also be produced using this Technology.
