A typical system for this type of machine starts with a two or three channel MSC controller to allow maximum flexibility.
Glue is stored in a stainless steel pressure feed tank and volume is controlled automatically via an electronic pressure regulator.  If required we can supply a diaphragm pump and connect to your external poly-container or drum.
We use Kaymich SV6 series spray valves fitted with high speed MAC series solenoids for accuracy and reliability.  These are non-contact and self cleaning minimising waste and down time. 
We have been asked on a number of occasions to add hot melt glue to make these machines even more versatile.