Composite coaxial tubes for refrigeration of corrosive liquids - involving copper, lead and polyethylene components

摘要

Heat exchanger tubes for cooling corrosive liquids (pref. acids) using liquid refrigerant (pref. freons) are made with a core tube of lead lined with copper for passing coolant while the corrosive liquid passes through an external coaxial tube of polyethylene. Suitable for cooling acidic bath liquors for treating metal, or sulphuric acid as used for anodic oxidation of aluminium. Polyethylene tube may have an external metallic sheath for increased mechanical strength.