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GRP PIPES: THE HELICAL FILAMENT WINDING PROCESS
Manufacturing Process:
The Helcal Filament Winding Process (Double Helix Filament Winding Process) uses CONTINUOUS GLASSFIBRE FILAMENTS impregnated in resin. The GRP pipes are manufactured in discrete lengths ( usually 12m ) on a rotating mandrel fitted on a Helical Filament Winder
The Helical Filament winder allows the Helical Filament Winding process to take place by impregnation of a number of glass reinforcing strands with a matrix resin, then applying the wetted fibers to the impervious liner formed initially on the mandrel, under controlled tension in a predetermined pattern.
The resin bath as illustrated below moves back and forth past a rotating mandrel. The angle of fiber placement, relative to the mandrel axis, is controlled by the relative translational speed of the bath and the rotational speed of mandrel fixed to the Helical Filament Winder. The speed translation is controlled by a computer controlled microprocessor.
Repeated passes establish a layered construction to achieve the desired wall thickness. Silica Sand if used is added during the winding process in the structural wall of the pipe to give necessary compressive strength., if required..
The resulting GRP pipe manufactured by the Helical Filament Winding process consists of multiple layers of unidirectional lamina. The angle at which the glass fibres are oriented in reference to the axis of the mandrel vary from 50 to 90 Degrees.
The Salient features of the Helical Filament Winding process are :
A Three Layered smooth, highly corrosion and chemical resistant impervious resin rich inner liner consisting of chemical resistant resin reinforced with C glass Surfacing veil, E glass mat and lastly chemical resistant mesh, wound under tension making the liner structure extremely compact and completely homogeneous.
Helically wound outer structural wall, with the resin impregnated CONTINUOUS Glassfibre Rovings filament wound in a criss cross manner at a pre-determined angle.
Bell and Spigot Joint (with optional locking mechanism requiring NO THRUST BLOCKS IN THE PIPELINE SYSTEM)
Bell and Spigot ends are integral and monolithic with pipe wall
By changing the winding angle different axial and hoop characteristics can be obtained.
Axial strength obtained is higher than pipes manufactured with other processes
Diameter Range : 25 mm to 4000 mm
Pressure Class Range : 3 bar to 35 bar>
Stiffness Class Range : 650 N/m2 to 10000 N/m2
Length : Maximum 15 meter lengths
Back to Process| Helical Filament Winding| Continuous Filament Winding
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