Water purifier having a multi-level boiler tray

Abstract

A distiller for producing potable water employs a metal boiler tray having a cover member in which there is an inlet for raw water and which together form a steam chamber having an outlet for steam. The boiler tray bottom has a plurality of steps including a highest, an intermediate and a lowest level step which are all covered with water at the beginning of a distillation cycle. The temperature of the highest level step is monitored with a sensor. A rise in the temperature of the highest level step by a predetermined amount above the boiling temperature of water indicates that the highest and intermediate level steps have become dry. This results in a signal to a controller to open a valve and admit replenishment raw water whose amount is dependent on valve open time. Steam evolved from the boiler tray is conducted through a first check valve in the cover member to demister chamber when the mist or carryover water in the steam impinges on a baffle and is separated from the steam as condensate. A feedback tube having a check valve interconnects the demister chamber with the steam chamber so that negative pressure in the steam chamber that accompanies infeed of cool raw water causes the condensate to be withdrawn from the demister chamber and returned to the boiler chamber.