Dispenser and fluid-driven proportioning pump

Abstract: A fluid dispenser includes a diluent fluid inlet; a fluid-driven proportioning air pump in fluid communication with a diluent fluid inlet, the air pump being driven by fluid from the diluent fluid inlet and having an air outlet isolated from the diluent fluid inlet; a fluid container having first and second openings, the first opening in fluid communication with the pump air outlet; and wherein the pump creates air pressure and flow to evacuate the container of fluid through the second opening. An associated method of evacuating fluid from a container includes supplying a diluent fluid to the proportioning air pump through the pump fluid inlet; delivering a volume of air from the pump air outlet to the container in order to displace a similar volume of fluid and evacuate that volume of fluid from the container; and diluting the evacuated fluid with diluent fluid from the pump fluid outlet.