The recirculation valve is used to prime the adjustable bottle top dispenser without wasting any of the chemicals. The bottle-top dispenser needs to be primed to get rid of air bubbles before the first usage or after sitting for a while.
A dispenser’s standard configuration includes a calibration scale (used to measure the quantity of fluid to be dispensed), a piston cylinder (used to accommodate the transfer of the reagent in and out of the bottle knob), an outer dispensing tube (linked to the spout to dispense the liquid out of the bottle), and an inner recirculation tube (used to recirculate the liquid back into the bottle). When the dispenser is in recirculating mode, the recirculating tube connects to an interconnecting region via a pair of notches to recirculate the liquid into the bottle.