The plants at Aquatech follow the procedure explained below to mould Extra tough water tanks, Cold Boxes, Loft tanks, customized moulds and public utility articles.

  • Extrusion
    Linear Low Density Polyethylene is mixed with Master Batch in the specified proportion
    Master Batch - Black                                                                            Master Batch – White  
    The extruder is set at temperature of 2000C. Plastic material and master batch are mixed in the specified proportion. Extruded with added carbon black ensures proper dispersion of carbon black throughout the material. As per IS 12701 the carbon content must be 2 to 3 % which is ideal to stop penetration of UV rays in the sunlight through the tank. The Master batch is made into continuous ribbons which are cooled in running water and made into pellets which then go on to be pulverized or powdered.

  • Pulverisation
    The 0.5 cm long pellets are put into the pulverisor and powdered to the requisite micron specifications. The mill is set at controlled speed and temperature of 700C and monitored every 30 mins. A process sieve helps collect the powder. The black powder is used to make the outer layer and the white is used to make the inner layer.

  • Feed to Mould
    The stainless steel mould is fed with the pulverized powder according to the size of the mould and covered with lid.

    Moulds of various capacity tanks are made providing enough flat space on the top side of the tank in order to allow a person to stand on it, for cleaning & other maintenance work, which is mentioned in IS 12701 for cylindrical vertical water tanks. Moulds are made cylindrical shaped with flat Bottom and a man hole is provided on the top side to allow a person to enter in to it if necessary; maintaining height and diameter measurements within the permissible limit of the standard.

    The weight of various capacity tanks are also maintained as per Clause 5.1 of the standard IS 12701.

  • Heat Chamber
    When the mould is completely in the heating chamber, the heating chamber door is closed. Then the gas oven and circulation blower are switched on. The chamber is set to predetermined temperature, speed (RPM) of arm and carrier and time for heating the mould. In case of white inside layer, white mix is fed through the top of the heating chamber through the funnel after the black powder has melted. An alarm sets off after the process is done.

    In order to maintain the specification, which insists the outer layer should be thicker than inner layer; Black/White powder ratio is maintained for different capacity of tanks.


  • Cooling
    The turret is transferred from the heating chamber to cooling chamber where it is cooled by exhaust and cooling fan for the required time. Then it is water sprayed to further cool.


  • Unloading & Finishing
    After it is cooled, the mould is ready for unloading. The tank is unloaded scraping off extra edges and visual tested for quality. It is checked for

    • Any black spot on the inner white surface. 
    •  Any slight black shade in the inner surface.
    • Any rough finish
    • Any lack uniformity of white layer and black layer.
    • Any pinhole at flash line.
    • Any foreign particle.                    

   If all is clear, the product is given a Batch No. which is punched on the flat surface at the