The process for manufacturing GRP pipe is the
continuously-advancing mandrel process on continuous filament winding machine.
The basic winder is composed of a continuous steel band supported by beams
which form a cylindrically shaped mandrel. The beams rotate; friction pulls the
band around and roller bearings allowing the band to move longitudinally so
that the entire mandrel continuously moves in a spiral path toward the end of
the machine.
As the mandrel moves, glass fibers, resin,fine graded filler, and surface materials are metered on, in precise amounts controlled by programmable logic controller and computer. The system provides integrated process control based on preprogrammed recipes. Another device measures the thickness of the laminate with rotation of the pipe at the cut. Minimum, maximum and average thickness are recorded and displayed on the operator's PC monitor. Raw materials are fed to the mandrel from overhead. A metering pump system, two glass fiber choppers, one sand unit feed and two polyester resin mixers with dispenser are included. A release film and surface mat and other surface liner materials are applied from rolls adjacent to the mandrel. Curing of the laminate is accomplished with a combination of induction heating through the steel band and infrared elements directly heating the laminate.
The pipe structure is composed of the
following material:
a- Internal
liner, made of ‘C’ type glass fiber impregnated with the resin
b- Structural
layer made of ‘E’ glass, resin and Silica Sand
c- Outer
Liner, made of ‘C’ type glass fiber impregnated with the resin
The saw and calibration unit is
synchronized with the continuous longitudinal movement of the laminate, which
ensures a clean perpendicular cut of the pipe. Pipes can be cut to any length
as preset. After passing the cutting station, the cured pipe is supported on
lifting tables that are specially designed for receiving the pipes. The pipe is
then moved by conveyor to the hydrostatic pipe tester.
