Apparatus for water purifying system and heater of increased efficiency

Claim 1

In a system for withdrawing water from a reservoir, heating it, and returning it to the reservoir: a suction line for withdrawing water from the reservoir and a return line for returning the water to the reservoir; a pump disposed between said suction line and said return line, for inducing a recirculating flow of water in said lines; a combustion heater having a flue for discharge of combustion gases; a venturi in said return line, having a throat through which all of said flow continuously passes so as to generate suction therein; an injection line communicating at one end with said heater flue and at its other end with the throat of said venturi, whereby suction applied to said other end by said venturi is applied at said one end to said flue, thereby to operate said heater with an excess of oxygen for improved combustion efficiency and to withdraw therefrom combustion gases and said excess of oxygen which are drawn into said venturi by said suction and mixed with said return flow; and a rate of flow regulating valve located in said injection line, operable to provide a continuous flow of said combustion gases at a constant rate such as to maintain a pH level in said reservoir such as to inhibit algae growth without external addition of acid into said reservoir.