Thermal softening and distillation by regenerative method

A method of softening hard water having dissolved salts therein with at least certain of the salts having solubilities which vary inversely with temperature comprising:

• providing a series of first interconnected chambers defining a first fluid flow path;
• providing a number of second interconnected chambers defining a second fluid flow path;
• placing each second chamber in fluid communication with a respective first chamber;
• directing a flow of hard water successively through said first chambers;
• urging said flow of hard water through a softening region at which said hard water is heated to a temperature sufficient to cause at least some of said certain dissolved salts therein to be precipitated;
• separating the precipitated salts from said water to purify the latter;
• directing said purified water successively through said second chambers;
• progressively reducing the pressure of said purified water as it flows through said second chambers to cause said purified water to flash into a vapor in each second chamber, respectively, and directing said vapor of each second chamber the corresponding first chamber and into direct, admixing contact with said hard water flowing therethrough to preheat said hard water before it reaches said region.

A method of forming a distillate comprising:

• directing a stream of incoming feedwater to be treated through a series of preheating regions;
• directing the feedwater through a treating area after the feedwater has passed through the regions;
• softening the feedwater at said treating area and separating precipitated impurities from the softened feedwater;
• forming water vapor adjacent to each region, respectively, in response to the flow of softened feedwater from said treating area;
• directing a portion of the water vapor of each region into direct contact with the incoming feedwater flowing therethrough to preheat the incoming feedwater;
• directing the remainder of the water vapor of each region to a location spaced from the path of incoming feedwater therethrough;
• and condensing the remainder of the water vapor at said location to form a distillate.

Apparatus for treating water having dissolved impurities therein with at least certain of the impurities having solubilities which vary inversely with temperature comprising:

• means defining a series of first interconnected chambers for successively receiving a flow of water having said dissolved impurities therein;
• means coupled with the downstream end of said series of first chambers for heating the waterflow therefrom to a temperature sufficient to cause at least some of said certain impurities therein to be precipitated;
• means coupled with said heating means for separating the precipitated impurities from said water therefrom to thereby purify said water;
• means defining a series of second interconnected chambers for successively receiving a flow of said purified water from said separating means, there being a second chamber for each first chamber, respectively;
• and a fluid flow path interconnecting each second chamber with a respective first chamber to permit flashed water vapor generated in said second chamber to flow into direct, admixing contact with said impure water flowing through said first chamber to thereby cause said impure water to be preheated by said water vapor before it reaches said heating means.

A distillation system comprising:

• a plurality of effects in series relationship with each other, each effect having a fluid inlet and a fluid outlet;
• means coupled with the inlet of a first of the effects for directing a feedwater stream thereinto;
• means coupled with the outlet of a second effect for receiving the feedwater stream thereof and for softening the same, and removing precipitated impurities therefrom to form purified water, the inlet and outlet of each remaining effect being coupled to adjacent effects in said series relationship;
• vapor formation means for each effect, respectively, for generating water vapor from said purified water;
• each effect having first means for permitting a first portion of said generated water vapor to combine with the feedwater stream directed thereinto to preheat the feedwater stream before the latter leaves the effect through said fluid outlet thereof, each effect having second means for directing a second portion of the water vapor to a location spaced from the region between the inlet and outlet thereof;
• and means at said location for condensing the second portion of water vapor to form a distillate.