Book back gluing nozzle system - has self adjusting pressure relief discharge at higher than application pressure

摘要

The nozzle system applies heat-melted, and particularly polyurethane, glue to the backs of book blocks passed over at intervals. A pump delivers the glue by pipe from a storage tank to a wide slot-shaped nozzle. There is a pressure-measuring unit in the pipe. The pump speed is regulated to give the pref rate of delivery,. A second pipe diverts the incoming glue when a valve in the first one shuts, and in the second pipe is a regulator valve adjusting the back-pressure dependent on the amt. of glue to be applied. The regular valve forms a pressure-relief valve, being self-adusting, and discharges the incoming glue during the intervals between applications. Its opposing force is adjusted so that its discharge pressure is above the necessary application pressure. The latter is measured beforehand, and fed to the controller for storage. ADVANTAGE - Even and precise application of glue is obtd..