Lacquer coating of large surface heat exchangers

摘要

The heat exchanger consists e.g. of plates (28) which are mounted a short distance apart on tubes (29). The aluminium surfaces of the heat exchanger have first been chemically etched and the whole unit is submerged in a vat of lacquer after which it is placed on a centrifuge to remove excess lacquer. After drying the process is repeated with a more viscous lacquer and again centrifuged. The thickness of the coating is controlled by varying the viscosity of the lacquer used and by controlling the speed and duration of the centrifuge stages.