Method for operating a suction device and suction device

A suction device, comprising

• a suction unit;
• a controller;
• a removable filtering device,
• wherein the suction unit generates a suction flow that flows through the filtering device when the filtering device is arranged on the suction device;
• a pressure sensor device that is arranged between the filtering device and the suction unit and provides pressure measured values of the suction flow downstream of the filtering device and upstream of the suction unit;
• and
• an evaluation unit implemented by the controller that, after the suction unit is started up, the evaluation unit is configured to perform a check whether the filtering device is present, the check comprising:
• accessing, by the evaluation unit, check data stored in a table of a storage device of the evaluation unit, or using, by the evaluation unit, an algorithm to compute the check data, the check data containing at least one threshold value or the algorithm defining the at least one threshold value, wherein the at least one threshold value includes a threshold value for switching off the suction unit, and wherein the at least one threshold value is a pressure value;
• comparing, by the evaluation unit, an absolute pressure value to the pressure value:
• generating and transmitting a switch-off signal from the evaluation unit to a switch of the controller if the absolute pressure value exceeds the pressure value thereby indicating that the filter device is not present,
• wherein the pressure value is determined from measurements in which suction hoses of different diameters are attached to the suction device and the pressure value measurements are measured with the filtering device used and without using the filtering device.