Screen-type screw centrifuge, comprising: a screw drive shaft extending along an axial axis, a screw hub fixed to an axial end of the screw drive shaft, a hollow screw main body which has a first screw main body axial end portion and a second screw main body axial end portion and which extends axially along the axial axis from its first to its second screw main body axial end portion in a direction opposite to a second axial end of the screw drive shaft and which comprises a screw main body circumferential wall extending around the axial axis, wherein the hollow screw main body is detachably fixed at its first screw main body axial end portion to the screw hub by means of at least one tightening means by which the screw main body and the screw hub are tightened against each other, a ring-shaped annular-gap cover which has a central opening for receiving a feed line for feeding material to be centrifuged into the interior of the screw main body and which extends from the screw main body circumferential wall to the central opening to cover an annular gap between the received feed line and the screw main body circumferential wall when the feed line is inserted into the opening, wherein the at least one tightening means has a tool engagement portion facing the second screw main body axial end portion, and wherein at least one axial access channel is formed radially between the screw main body circumferential wall and the annular-gap cover, through which the tool engagement portion of the respective tightening means is axially accessible from the second screw main body axial end portion, wherein the hollow screw main body is in the form of a hollow screw cone, wherein the first screw main body axial end portion is a small-diameter axial end portion of the screw cone, and the second screw main body axial end portion is a large-diameter end portion of the screw cone, the screen-type screw centrifuge further having a rotatably supported screen drum comprising a screen drum circumferential wall, by which the screw main body is surrounded around the axial axis and which is equipped with a screen means, characterized by an adjusting ring disk which extends around the axial axis and which is axially placed between the screw main body and the screw hub, and by means of which a radial gap between the screw main body and the screen drum circumferential wall is adjustable, wherein the adjusting ring disk is axially tightened by means of the respective axial tightening means together with the screw main body and the screw hub. a screw drive shaft extending along an axial axis, a screw hub fixed to an axial end of the screw drive shaft, a hollow screw main body which has a first screw main body axial end portion and a second screw main body axial end portion and which extends axially along the axial axis from its first to its second screw main body axial end portion in a direction opposite to a second axial end of the screw drive shaft and which comprises a screw main body circumferential wall extending around the axial axis, wherein the hollow screw main body is detachably fixed at its first screw main body axial end portion to the screw hub by means of at least one tightening means by which the screw main body and the screw hub are tightened against each other, a ring-shaped annular-gap cover which has a central opening for receiving a feed line for feeding material to be centrifuged into the interior of the screw main body and which extends from the screw main body circumferential wall to the central opening to cover an annular gap between the received feed line and the screw main body circumferential wall when the feed line is inserted into the opening, wherein the at least one tightening means has a tool engagement portion facing the second screw main body axial end portion, and wherein at least one axial access channel is formed radially between the screw main body circumferential wall and the annular-gap cover, through which the tool engagement portion of the respective tightening means is axially accessible from the second screw main body axial end portion, wherein the hollow screw main body is in the form of a hollow screw cone, wherein the first screw main body axial end portion is a small-diameter axial end portion of the screw cone, and the second screw main body axial end portion is a large-diameter end portion of the screw cone, the screen-type screw centrifuge further having a rotatably supported screen drum comprising a screen drum circumferential wall, by which the screw main body is surrounded around the axial axis and which is equipped with a screen means, characterized by an adjusting ring disk which extends around the axial axis and which is axially placed between the screw main body and the screw hub, and by means of which a radial gap between the screw main body and the screen drum circumferential wall is adjustable, wherein the adjusting ring disk is axially tightened by means of the respective axial tightening means together with the screw main body and the screw hub.