Patent ID: 7753232

Claim:
A fluid dispensing apparatus to dispense a predetermined volume of fluid comprising: a fluid reservoir connected to a fluid supply; a dispense tube connected to the fluid reservoir and having a dispense outlet, said dispense tube comprising a measurement portion to measure a predetermined volume of fluid to be dispensed, and a dispense portion to dispense the predetermined volume of fluid; a dispense tube vent valve connected to the dispense tube; an elevator mechanism to selectively raise and lower the dispense portion of the dispense tube; a first measurement sensor disposed proximate the measurement portion of the dispense tube to generate a first signal responsive to detecting when a rising volume of fluid in the measurement portion has reached a desired fill level; a second measurement sensor disposed proximate the measurement portion and below the first sensor generate a second signal responsive to detecting when a falling volume of fluid in the measurement portion has reached a desired dispense level; and a dispensing sensor disposed proximate the dispense portion to generate a third signal responsive to detecting when the dispense tube is filled to a predetermined level; a processor programmed to: control the elevator mechanism to raise the dispense tube to a raised filling position to prevent fluid flow from the dispense outlet; open the dispense tube vent valve when the dispense tube is in the raised filling position; fill the dispense tube with fluid from the fluid reservoir to the level of the dispensing sensor; close the dispense vent valve responsive to the first signal when the fluid level in the measurement portion rises to the level of the first sensor; control the elevator mechanism to lower the dispense tube to a lowered dispensing position responsive to the third signal from the dispensing sensor; open the dispense tube vent valve when the dispense tube is in the lowered dispensing position to dispense the predetermined volume of fluid from the dispense tube; and close the dispense tube vent valve responsive to the second signal indicating that the predetermined volume of fluid has been dispensed.