Multistage submerged tube evaporator - in common tank using heat of condensation of successive stages for heating after first

摘要

Multi-stage submerged tube evaporator for desalination of seawater heats the seawater in the first stage by an external heat source and uses for the other stages the heat of condensation of the preceding stage. The stages are arranged directly above each other, with the steam pipe of each lower stage joined to the condensation tube of each higher stage submerged in the seawater. Each condensation tube has at its outlet a throttle valve which is set to maintain a higher pressure in each lower stage compared with the next higher stage and to keep the pressure in every stage above ambient pressure. Such an evaporator is compact and light in wt. It requires little space and is functionally reliable. It requires no special or expensive forms of energy.