Chemical Storage Tanks
Polyethylene resins used for rotational moulding of storage tanks show excellent resistance to a wide range of chemicals and are generally resistant to inorganic acids, alkalis and aqueous solutions. They contain ultra-violet stabilizers to reduce the effect of photo-oxidation and show excellent impact resistance, are very good electrical insulators and show low thermal conductivity relative to metal When contemplating the use of polyethylene in building storage tanks, designers should however avoid its use at temperatures below minus 20 or above 40 deg C and restrict use in contact with surface active substances such as alcohols, soaps and wetting agents.
Polyethylene is suitable for storing acids such as Sulphuric and Citric, alkalis’ such as Sodium Hydroxide and Ammonium Hydroxide, plus a wide range of other chemicals. Tank fittings in chemical applications are typical also made from polyethylene and are welded to the tank prior to delivery. Stainless steel fittings are used in some applications and if necessary can be fitted on site.
In specifying storage vessels customers are encouraged to clearly state the nature of the liquid being stored, the physical environment in which the tank is to be installed and what, if any, additional hazards may exist.
West Coast Poly manufacturing processes are designed to achieve the optimum properties from the moulded material and can offer impact testing in accordance with AS/NZ 4766. Welded fittings are installed by qualified personnel in accordance with DVS 2207 and non-destructive spark testing of welds or hydrostatic testing of vessels can be provided.
The provision of a Material Safety Data Sheet and maximum service temperature range is essential if the vessel is to carry a manufacturer warranty.