Patent ID: 7861367

Claim:
Vacuum cleaner with a dirt collection tank having a suction inlet and being in flow connection with at least one suction unit via at least one filter and at least one extraction line, and with at least one external air inlet opening into the extraction line downstream of the at least one filter, said external air inlet being closable by means of at least one closing valve, wherein the at least one closing valve has a valve member movable back and forth between a closing position, said valve member abutting on a valve seat in said closing position, and an open position, said valve member being spaced from the valve seat in said open position, wherein said valve member is acted upon by a spring-elastic restoring device with a closing force and in the closing position, in addition, by a magnetic holding device with a magnetic holding force, wherein the magnetic holding device has an electromagnet adapted to be acted upon with an exciting current for the purpose of closing the closing valve, wherein the electromagnet is connected to an electrical switching unit for the purpose of switching the exciting current on and off, and wherein the valve member is movable continuously back into the closing position via the open position, proceeding from the closing position, when the exciting current is interrupted, wherein the switch-off time of the exciting current is adapted to the movement time of the valve member.