Responsive control of pipework pressurisation, pressure fluctuation and uneven delivery in viscous material dispensing systems

摘要

This method extracts and delivers viscous material e.g. a plastic, using an air-driven piston pump. This pumps the material from a vessel via a line to a dispensing unit. In the new arrangement, the pressure of the material at the dispensing unit is regulated to a desired value. For this purpose its pressure is measured. On deviation from the desired value, the air pressure driving the piston pump is controlled accordingly. Also claimed is the corresponding equipment in which a servo controller (34) varies air pressure supplied to the motor (26) driving the pump (24). The actual value of material pressure is measured by a sensor (36) for this purpose, at the delivery unit (30). Preferably the piston pump is a double acting unit, and is especially a drum or barrel extraction pump.