Filter device and method for switching on and/or switching off such filter device

A filter device for separating impurities from a gas to be purified,

• whereby the filter device (1) includes a filter housing (2) consisting of a lid (3) and a pot (4);
• whereby the lid (3) is provided with an inlet (6) for gas to be purified and an outlet (7) for purified gas;
• whereby in the pot (4) a filter element (9) is installed, which filter element (9) consists of a top cap (10) and a bottom cap (11) with a filter cartridge (12) in between;
• whereby the top cap (10) is provided with an inlet duct (17) with an entrance (18), which entrance (18) can connect to the inlet (6) of the lid (3) in such a way that the gas to be purified is passed through the inlet duct (17) to the filter cartridge (12);
• and
• where there is a space (21) between the lid (3) and the top cap (10) which can be connected to the outlet (7) of the lid (3),
• characterized in that the filter device (1) is further provided with a switching element (22) with an inlet port (23) and an outlet port (24), the switching element (22) being configured in such a way that
• it can be installed rotatably in the lid (3);
• and
• it can be rotated between on the one hand an off-position, in which the inlet port (23) or the outlet port (24) connects to respectively the inlet (6) or outlet (7) of the lid (3), and on the other hand a twisted position, in which this is not the case and in which the entrance (18) of the inlet duct (17) of the top cap (10) can connect to the inlet (6) of the lid (3).