Method for controlling the delivery pressure of a supply pump

A method for controlling delivery pressure of a supply pump in a system for delivering and metering a viscous material, wherein the system has a supply pump, a metering pump, and a delivery line which extends between the supply pump and the metering pump, and wherein the supply pump delivers the viscous material from a material store to an inlet of the metering pump through the delivery line using a delivery pressure D, wherein, furthermore, a pressure buffer which is pretensioned to a pretensioning pressure P and has a variable buffer volume is connected upstream of the inlet of the metering pump, wherein the buffer volume can receive viscous material from the delivery line when the delivery pressure in the delivery line in the region of the pressure buffer is higher than the pretensioning pressure P of the pressure buffer, and viscous material can be dispensed into the delivery line from the buffer volume when the delivery pressure in the delivery line in the region of the pressure buffer is lower than the pretensioning pressure P of the pressure buffer, wherein the system additionally has a pressure sensor, connected upstream of the inlet of the metering pump for detecting an actual pressure value in the delivery line, and a control unit, wherein the control unit is connected to the pressure sensor, the supply pump, and the metering pump and receives a signal from one or more of them, wherein the control unit transmits a specification value to the supply pump based on a deviation between a specified target pressure value and the actual pressure value in the delivery line as well as operating state of the metering pump;

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• wherein, in addition to the signal from the pressure sensor and the signal from the metering pump regarding its operating state, information regarding the fill level in the buffer volume is also included in the control.