The sand-filled, glass-fibre reinforced polyester pipes belong to the group of so-called composite plastics, they will be produced of the combination of different raw materials (e.g. polyester resin, glass-fibre materials, silica sand), by filament winding technology. The applied materials will be chosen with the aim to achieve the required characteristics and quality of the product.
The binding material of the product guarantees structural integrity, watertightness and chemical resistance of the components.
Materials containing glass
Characteristics of strength and mechanical properties will be determined mainly by continuously winded glass-fibres, chopped glass-fibres and glass veil.
- ECR glass-fibre materials,
- C glass-fibre materials.
Mixed with polyester resin it is the filling material of the pipe, it has got important role in the wall structure and the increase of the pipe stiffness.
Further to these materials, some auxiliary materials are also needed for the production of sand-filled pipes. While processing, these (accelerator, initiator, inhibitor) are contained by the polyesther resin. Polyesther resins used by the production result in thermoreactive products, i.e. no softening or deformation are caused by heat.
Budaplast pipes will be produced by filament winding procedure on production moulds of profiles and sizes according to the requirements of reconstruction projects. The typical sizes of moulds have been developed on the basis of client orders during many decades, but the manufacturer is ready to widen the range of profiles according to any new and individual requirements. The wall structure will be built up beginning from the core of the rotating mould to the outside continuously by laying on the row materials one by one. Typical lengths of shape are 1.0 m; 2.3 m; 3.0 and 6.0 meters, which means also the maximals lengths of pipe pieces.
Typical structure of layers
L4 - outer reinforcing layer: a layer consisting of filament winded glass-fibres, with a sand coating outside
L3 - stiffening layer: a stiffening core consisting of resin and silica sand
L2 - inner reinforcing layer: a layer consisting of continuous filament winded glass-fibres
L1 - inner layer resistant to abrasion: a layer rich in resin with a reinforcement of glass veil and chopped glass-fibres
Structure of layers in the case of wall thickness less than 9 mm
L3 - outer reinforcing layer: a layer consisting of filament winded glass-fibres, with a sand coating outside
L2 - inner reinforcing layer: a layer consisting of continuous filament winded glass-fibres and sand
L1 - inner layer resistant to abrasion: a layer rich of resin with a reinforcement of glass veil and chopped glass-fibres
Gravity GRP pipes will be connected usually by a socket and a rubber ring. The socket will be created on the mould parallelly with the pipe production. A slot will be cut on the spigot end of the pipe at the time when the pipe is being cut to size and a rubber ring will be put on in order to guarantee watertightness.
The outer side of the pipewall will be made rough by sand, so the structural integrity of the cement mortar grouted into the annular space between the GRP pipe and the old pipe will be guaranteed.