Automatic chlorinator

An automatic chlorinator for a swimming pool having a water circulating system including a pump comprising, in combination, a reservoir for storing a chlorine saturated water solution, a dual chambered sample vial having a light source therein, conduit means operably connecting the high pressure side of the pump with the sample vial for introducing pool water into both chambers thereof, means for introducing a metered amount of reagent into one only of the chambers for mixing with the pool water therein, said means for introducing a metered amount of reagent including a reservoir for the reagent, conduit means connecting said reservoir with said one sample vial chamber, and a solenoid valve is said conduit means, a spectral filter for the other of said chambers, a photocell for each chamber, the light source operating to direct light rays onto the photocell for each chamber after passing through its contents and said filter, a clock assembly, normally closed valve means in the conduit means connecting the pump with the sample vial, the clock assembly being operable at regular intervals to open the valve means whereby pool water is introduced into the sample vial chambers, means controlled by the valve means for actuating the reagent introducing means, said means for actuating the reagent introducing means including a delay circuit forming a part of the control circuit, said delay circuit operating to energize the solenoid valve that forms a part of the reagent introducing means when the valve means tha permits pool water to be introduced into the sample vial chambers de-energizes, the delay circuit including a series connected capacitor and resistor for controlling the time interval that the reagent solenoid valve remains energized, a control circuit for comparing the output signals of the photocells to determine whether the residual chlorine in the pool water is or is not below a predetermined desired level, the control circuit including means for providing an output signal if the residual chlorine is below the predetermined desired level, conduit means operably connecting the reservoir to the low pressure side of the pump, and normally closed valve means in the last-named conduit means openable by said last-named output signal to permit chlorine saturated solution to flow from the reservoir to the pool.