Patent ID: 7543720

Claim:
A method of dispensing small amounts of fluid comprising the steps of first assembling a system comprising a nozzle having a source end and a dispensing end, a pump device having an inlet port, an outlet port, and a chamber of variable volume therebetween with means for controllably varying the volume of said chamber, a pneumatic control valve connected to the inlet port of said pump device and a flow control valve connected between the outlet port of the pump device and the source end of the nozzle; and inserting the dispensing end of the nozzle into a source of fluid to be dispensed; and causing a negative pressure within the pump device and exposing the source end of the nozzle to the negative pressure within the pump device, thereby causing aspiration of the fluid to be dispensed into the nozzle; and then creating a positive pressure within the pump device; and then exposing the source end of the nozzle to the positive pressure within the pump device for a predetermined time by opening the flow control valve for the predetermined time, thereby dispensing a controlled amount of the fluid to be dispensed from the nozzle.