23 in the form of spirals the upper termination of the support body 2 is its upper end 24 below that is the upper ring area 26 of the support body 2 which serves as the sealing rest of the ring filter insert 3 fig6 shows the support body 2 in a view onto its underside in the center of fig6 the view extends through the central second flow channel 22 up to the vent throttle 25 at the upper end of the support body 2 the first flow channel 21 lies on the left of flow channel 23 the third flow channel 23 lies on the right of the central flow channel 22 the sealing groove 27 1 u2032 runs around the flow channel 21 the sealing groove 27 2 u2032 runs around the flow channel 23 as illustrated in a joint view of fig2 and 6 the central area of the base 11 and the lower front end of the support body 2 are geometrically coordinated such and adjusted to each other that u2014 with the support body 2 firmly screwed together with the housing base 11 u2014 the flow channels 21 and 23 are lined up with the pure fuel outlet 14 and the raw fuel inlet 13 to this end the aforementioned threads 18 and 28 are arranged such that upon screwing the support body 2 to the housing base 11 an.