The RD-3 Glue dispensing valve is designed for non-contact dispensing of adhesives, silicones, lacquers, oils. This glue dispensing valve working on pneumatic principle.
You can open and close the RD-3 Cold glue applicator nozzle with a pressured air in the blue tubes in this picture.
The could glue is undere pressure and connected to the RD-3 Cold glue applicator nozzle with the white tube.
You can drive the glue from a glue tank which is under pressure, or you can pump the glue into the RD-3 Cold glue applicator nozzle.