Semi-trailers equipped with tanks are used to transport liquid cargoes like fuels and gas, foodstuff and dry bulk cargoes. Tank capacity depends on the accepted total weight of the vehicles and the relative density of the transported cargo. So for cement transportation, tanks of small capacity are used, and petroleum fuels require tanks of much large capacity.
The structure of tank semi-trailer can be very different: a single-body frame; a double layer with thermo-insulating coating; an ability to work under pressure; a multi-section construction. Thus, this type of trailers is highly specialized for specific use. Therefore, if you plan to buy a used tank semi-trailer, you should choose the model, which is the most suitable for the actual operating conditions.
For the details on the types of a tank semi-trailer, its manufacturers and the tips on how to pick a used tank semi-trailer for sale go on here.