Liquid dispensing module and methods for dispensing a heated liquid onto a
substrate. The dispensing module includes a dispenser body receiving
liquid from a heated liquid distribution manifold and an actuator having
a housing with an air piston movable in an air cavity and a solenoid
valve for pressurizing the air cavity. Movement of the air piston
controls a flow-regulating mechanism for selectively dispensing liquid
from the dispenser body. A thermally insulating shield may be provided
for reducing heat transfer from the manifold and/or dispenser body to the
actuator so that the solenoid valve can be mounted directly to the
housing and the effective volume of the air cavity can be reduced. The
cycle time of the liquid dispensing module may be specified by selecting
an initial volume of the air cavity and an effective valve flow
coefficient for the actuator that characterizes the air flow to the air
cavity.