Condenser for water purification apparatus

摘要

A distillation type of water purification system has a raw water inlet valve for admitting raw water continuously to a boiling tank at a rate greater than the rate at which raw water is converted to treated water. A drain valve located at the bottom of the boiling tank is energized by a raw water level sensing means whenever the raw water level reaches a predetermined level, to discharge water from the boiling tank. Treated water is stored in a storage tank having a pump for discharging treated water to the user upon demand. A single conductivity sensor in the storage tank controls the pump to allow it to operate only if the sensed conductivity is above a first predetermined value but not at or above a second predetermined value greater than the first value. An improved condenser has two sets of tubes, each set is arranged in a pair of planes oriented transverse the flow of cooling air with the tubes parallel. The internal cross-sectional area of one set is about twice that of the other. Steam and condensate flows serially through the larger diameter tubes and then through the smaller diameter tubes in a flow countercurrent to the cooling air stream.