The filter is composed of a filter chamber (1) in which is arranged a filter unit (6). A gas inlet (4) and a gas outlet (5) are connected to the filter chamber (1). The gas inlet (4) is composed of a short diffusor (12), the outlet cross-section (14) of which lies opposite a prepurifier (7) which covers the filter unit (6) and separates a prechamber (11) from the filter chamber (1). The prepurifier (7) is composed of a curtain (9) which is formed by lamellas (8), by which coarse dust is separated off from the gas to be purified and passes out of the prechamber (11) into a central dust collection space (10) which is arranged beneath the filter unit (6). In this filter it is thus unnecessary to provide, in addition to the prepurifier (7) means for separating off coarse dust from the gas to be purified, separate discharge of the coarse dust and the remaining dust retained by the filter unit (6) also being unnecessary. <IMAGE>
