Apparatus for metering and dispensing viscous substance

A method of metering and dispensing a volume of a viscous substance, comprising:

• filling, via a supply valve disposed in a supply flow path:
• a part of the supply flow path downstream of the supply valve,
• a part of a dispensing flow path fluidly connected to the supply flow path downstream of the supply valve, and
• a part of a metering flow path fluidly connected to the supply flow path downstream of the supply valve, the part of the metering flow path being defined by a metering piston disposed in the metering flow path in an unloaded position;
• closing a dispensing valve disposed in the dispensing flow path to define the part of the dispensing flow path;
• pressurizing the viscous substance to a pressure sufficient for the viscous substance to move the metering piston from the unloaded position to a predetermined loaded position and thereby predetermining the volume of the viscous substance to be dispensed;
• after the metering piston reaches the loaded position, closing the supply valve to enclose the volume within the parts of the supply flow path, the dispensing flow path and the metering flow path, and opening the dispensing valve;
• after the opening the dispensing valve, moving the metering piston to the unloaded position to move the volume of the viscous substance into the dispensing valve;
• after the moving the metering piston to the unloaded position, moving the dispensing valve to a position in which the bore of the dispensing valve aligns with both a dispensing piston and an outlet;
• and
• moving the dispensing piston through the bore of the dispensing valve to dispense the volume of the viscous substance via the outlet.