Method for operating a delivery apparatus, and delivery apparatus

A method for operating a delivery apparatus for delivering a flowable construction material, wherein the delivery apparatus comprises a control device, an eccentric screw pump having a rotor-stator unit with an outlet, and a drive unit, comprising the steps:

• a target pressure at the outlet of the eccentric screw pump or at a delivery section arranged downstream of the outlet is preset at a target-pressure setting device,
• a characteristic variable, including at least one of a mechanical power, electrical power, a rotational speed, a torque, and a current of the drive unit of the eccentric screw pump is measured,
• an actual pressure in a region of the outlet of the rotor-stator unit and/or in the delivery section arranged downstream of the outlet is measured by at least one pressure sensor,
• a change in the actual pressure measured by the at least one pressure sensor is related to at least one of the characteristic variables,
• wherein, in the event of a rise in the actual pressure above the target pressure, a reduction at least of one of the characteristic variables is adjusted by the control device so that the target pressure is achieved again,
• wherein, in the event of a pressure drop in the actual pressure below the target pressure, an increase at least of one of the characteristic variables is adjusted by the control device so that the target pressure is achieved again, and
• wherein, in switching positions, in which an operating-mode setting device is adjusted to “filling and cleaning the eccentric screw pump”, pressure changes detected by the at least one pressure sensor are ignored by the control device and, in said switching positions of the operating-mode setting device, the drive unit is operated at a constant rotational speed or at a constant torque or at a constant power which is greater than 0% and at most 50% of a rotational speed or a torque or a power with which the drive unit is operated in a “normal mode”.