LIQUID MATERIAL DISPENSER

PROBLEM TO BE SOLVED: To provide a liquid material dispenser which can dispense a liquid material over a wide range of viscosity, especially the liquid material of high viscosity, since known systems have significant variations in the volume of material dispensed with each dispensing operation. SOLUTION: Methods and apparatus for dispensing the liquid material provide an option to dispense precise and repeatable quantities or volume of the material over a wide range of viscosity. In one embodiment, a metering chamber is provided that can be filled and emptied at the same time so as to eliminate time delay between dispensing operations. The material may be under pressure and that pressure is used to fill and empty the metering chamber. In another embodiment, a control device is provided with the metering chamber wherein the control device operates to switch pressurized fluid between two passages to the metering chamber. In a more specific embodiment, the control device may be, for example, a valve and more specifically in one embodiment, the control device may be a pneumatically actuated spool valve. COPYRIGHT: (C)2010,JPO&INPIT