1. Manufacture of tanks PLAVISA

The process starts in the Commercial Department which places an order and gives all the information to the Technical Department (plans, sketches, and customer data). The Technical Department draws the manufacture plans, which are sent to the customer in order to be accepted or checked by him. In this stage characteristics of designs made before are taken into account, but each tank is unique.

Once the plans are accepted, the technical documentation (calculations, manufacture data, accessories and so on) is done and given to the Production Department which shares out to sections. Methodology, stages, parameters and patterns of manufacture process are established in the Specific Methods of Quality System done for each section and which constitute part of Know-How of PLAVISA.

In order to manufacture a tank, firstly, the shells (cylindrical part) are made by the system of Filament Winding in the section of Mandrels, and the fonds (caps) are made by the system of simultaneous projection After that, the different parts are sent to the section of Assembly, and then the shells and fonds are joined by the system of rolled.

At the same time, the section of Accessories manufactures the rest of parts which compose the tank, Such as manholes, flanges, exits of air, and so on. In this section, different systems of manufacture are used, depending on the part to manufacture (moulding by cool press, moulding by vacuum, and so on)

Next, the complete tank is taken to the Clinic section, where all the accessories and flanges are placed. In order to do that, the location of the different parts is drawn up on the tank and the areas to join are sanded. Accessories and flanges are placed and are rolled to the tank.

After that, the tank is subjected to a process of curing in a furnace at 80ºC for three or four hours, in order to strengthen the cured polyester. By this process, PLAVISA achieves that its tanks reach a bigger high degree of chemistry and mechanical resistance, due to a higher degree of evaporation of residual styrene. In tanks used in alimentary industry, a treatment with steam of water is given later in order to clean perfectly and makes the tank aseptic.

Different tests (dimensional control, visual inspection, hardness control, hydraulic test and so on) are made during the whole manufacture process in order to check that the tank has been done according to plans and does not show any defect.

The tank is sent to the customer with all its accessories, such as metallic structures which are set up at the Mechanical Garage section or thermometers, elements, valves, and so on, just as a detailed Manual of Assembly and Maintenance.

If it was necessary, the installation of tanks could be done where the customer needs. PLAVISA is able to do any job of repairs, alteration or maintenance at the customer’s facilities, as well as specialized jobs, such as covering and so on.

2. Manufacture systems

Any process of GRP manufacture consists of impregnating glass fibres with resins. Like this, the processes used by PLAVISA are:

Hand contact moulding or laminated:

Procedure of moulding resins by hand layout and impregnation of the stratification of glass fibres. It is generally based on the combination of polyester resin and the glass fibre which is handled to adopt the shape of the mould of the components to join. The process is done at room temperature and it can be accelerated chemically or increasing the temperature.

Filament Winding:

The filament winding is an automatic process of high volume which is ideal to manufacture pipes, tanks, pressure glasses and other cylindrical shapes. This procedure allows obtaining empty pieces by winding of different reinforcements of glass impregnated by a resin which hardens by temperature, on a retractable mandrel, with numerical control. Its optimum qualities are obtained when the strain of fibre is the same in all the fibres. The mandrel rotates at the same time the roving is winding up through its whole length. Due to the winding up action, the filament compacts to the laminate, that’s why other compaction methods are not necessary.

Procedure of moulding by Cold Moulding:

It consists of pouring the liquid resin inside a closed compartment which is composed of mould and against-mould. The glass fibre reinforcement has previously located inside this closed compartment. Unlike other systems of moulding by press, low pressures and not much high temperatures are reached by this procedure which is a decisive factor for the compound to reach its highest levels of chemical and mechanical resistance.

Procedure of moulding by Simultaneous Projection:

It is a procedure of moulding of thermo stable moulds where glass fibre and resin are simultaneously applied on the mould by an equipment of projection.

Procedure of moulding by vacuum: