Method and apparatus for dispensing small amounts of liquid material

摘要

Apparatus and methods for dispensing droplets of liquid or viscous material are disclosed. A valve is opened to dispense a stream of the heated liquid or viscous material through an elongated orifice of a nozzle. The stream of material being dispensed from the elongated orifice is broken into droplets by rapidly closing the valve. Furthermore, a method for varying the height of a droplet of liquid or viscous material is disclosed by which two or more droplets combine to form a droplet of a desired height. A method for applying a plurality of droplets of material onto a substrate so that the droplets flow together to form a uniform film of desired thickness and shape is also disclosed. A second embodiment of the invention relates to dispensing apparatus with a heater assembly removably attached to the dispenser housing. Another modification of the invention relates to a modified seat assembly wherein the valve has three positions with respect to the valve seat and a modified nozzle assembly wherein the nozzle is constructed of a thin walled tube.