Dispenser and method for dispensing viscous fluids

A dispenser for dispensing discrete predetermined micro quantities of viscous fluid, the dispenser comprising:

• a viscous fluid supply for supplying pressurized viscous fluid to the dispenser;
• a viscous fluid outlet for dispensing viscous fluid from the dispenser;
• a viscous fluid passageway fluidly connecting said viscous fluid supply and said viscous fluid outer;
• said viscous fluid passageway connecting an outer feed cavity and an inner dispense cavity, and an inter-cavity dam between said inner and outer cavities, such that during the dispensing process the viscous fluid travels from said outer cavity to the inner cavity, via said viscous fluid passageway;
• a diaphragm having a first position and a portion thereof mounted for reciprocatory movement, said diaphragm having a first surface and a second surface opposed from said first surface, said first surface defining one boundary of said viscous fluid passageway such that movement of the movable portion of the diaphragm to a second position closes said passageway at said dam, and movement of said diaphragm to a third position dispenses viscous fluid from said outlet;
• a diaphragm actuator imparting reciprocatory movement to the movable portion of said diaphragm, said diaphragm actuator including a controllable pressurized actuator fluid source in fluid communication with the second surface of the diaphragm to cause the reciprocatory movement of the movable portion of said diaphragm;
• and
• a diaphragm position sensor for determining the relative position of the movable portion of the diaphragm, said diaphragm position sensor being functionally coupled to the diaphragm actuator such that the diaphragm actuator is controllable in accordance with the relative position of the movable portion of the diaphragm permitting the accurate control of predetermined micro quantities of viscous fluid dispensed from the dispenser.